iron ore smelting process - bright hub engineering

iron ore smelting process - bright hub engineering

Here the ore is put into a blast furnace along with limestone and coke and subjected to hot air blasting and heat which converts the ore to molten iron. This is tapped from the bottom of the furnace into molds known as pigs and allowed to solidify into pig iron.This pig iron is converted to wrought iron or processed into steel by several methods.This is the first article in a series on metallurgy, where we will examine the processing of iron ore into different grades of steel. We start with the mining and preparation of the iron ore and shipping it to the smelter.The Mining of Iron OreIron ore mining was a thriving industry in many parts of the world, with the smelters being located as close to the mines as possible. However as larger mines where more efficient mining of higher iron content ore became effective, the smaller mines fell by the wayside.The top four mines with the highest output of iron ore are in China, Australia, the US, and South Africa.There are two distinct categories of iron ore mining, surface mining such as open cast or strip mining and underground mining.At the surface iron ore processing plants, the iron ore is put through crushers and ball mills to break it into a uniform and more workable size and then washed with the residue going to tailings.The ore is the transported to the various smelters located locally or on the other side of the world with large bulk carriers being used to ship the ore by sea.Iron Ore Smelting Process Using Modern Blast Furnaces.Although the basic ingredients of an iron ore blast furnace has changed little over the last hundred years or so, the furnaces themselves have been modernized to improve efficiency and the purity of the iron and steel.The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

This is the first article in a series on metallurgy, where we will examine the processing of iron ore into different grades of steel. We start with the mining and preparation of the iron ore and shipping it to the smelter.The Mining of Iron OreIron ore mining was a thriving industry in many parts of the world, with the smelters being located as close to the mines as possible. However as larger mines where more efficient mining of higher iron content ore became effective, the smaller mines fell by the wayside.The top four mines with the highest output of iron ore are in China, Australia, the US, and South Africa.There are two distinct categories of iron ore mining, surface mining such as open cast or strip mining and underground mining.At the surface iron ore processing plants, the iron ore is put through crushers and ball mills to break it into a uniform and more workable size and then washed with the residue going to tailings.The ore is the transported to the various smelters located locally or on the other side of the world with large bulk carriers being used to ship the ore by sea.Iron Ore Smelting Process Using Modern Blast Furnaces.Although the basic ingredients of an iron ore blast furnace has changed little over the last hundred years or so, the furnaces themselves have been modernized to improve efficiency and the purity of the iron and steel.The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Iron ore mining was a thriving industry in many parts of the world, with the smelters being located as close to the mines as possible. However as larger mines where more efficient mining of higher iron content ore became effective, the smaller mines fell by the wayside.The top four mines with the highest output of iron ore are in China, Australia, the US, and South Africa.There are two distinct categories of iron ore mining, surface mining such as open cast or strip mining and underground mining.At the surface iron ore processing plants, the iron ore is put through crushers and ball mills to break it into a uniform and more workable size and then washed with the residue going to tailings.The ore is the transported to the various smelters located locally or on the other side of the world with large bulk carriers being used to ship the ore by sea.Iron Ore Smelting Process Using Modern Blast Furnaces.Although the basic ingredients of an iron ore blast furnace has changed little over the last hundred years or so, the furnaces themselves have been modernized to improve efficiency and the purity of the iron and steel.The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

There are two distinct categories of iron ore mining, surface mining such as open cast or strip mining and underground mining.At the surface iron ore processing plants, the iron ore is put through crushers and ball mills to break it into a uniform and more workable size and then washed with the residue going to tailings.The ore is the transported to the various smelters located locally or on the other side of the world with large bulk carriers being used to ship the ore by sea.Iron Ore Smelting Process Using Modern Blast Furnaces.Although the basic ingredients of an iron ore blast furnace has changed little over the last hundred years or so, the furnaces themselves have been modernized to improve efficiency and the purity of the iron and steel.The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

The ore is the transported to the various smelters located locally or on the other side of the world with large bulk carriers being used to ship the ore by sea.Iron Ore Smelting Process Using Modern Blast Furnaces.Although the basic ingredients of an iron ore blast furnace has changed little over the last hundred years or so, the furnaces themselves have been modernized to improve efficiency and the purity of the iron and steel.The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Although the basic ingredients of an iron ore blast furnace has changed little over the last hundred years or so, the furnaces themselves have been modernized to improve efficiency and the purity of the iron and steel.The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

The furnace has a more efficient shape to suit automation, with the contents of iron ore, limestone and coke being carefully measured, conveyed and loaded into the furnace from the top through specially designed gas-tight valves. High temperature air at over 1000C (which is can be heated using the exhaust gasses from the furnace much like a boiler economiser) is blasted into the bottom of the furnace through several tuyeres.

The coke is used as a fuel to produce the high temperatures required by the process of smelting the ore in a blast furnace. It produces CO which adds heat, as well as acting as a reducer removing the oxygen content from the ore.Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.Converting Pig Iron to Wrought Iron and Steel.The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Limestone is used as a flux to separate the gangue from the molten iron ore, the accumulated slag and the molten iron being tapped from two tap-holes at the bottom of the furnace. The slag goes to a disposal area and the molten iron is directed into molds known as pigs where it solidifies to pig iron and is transferred to the next stage of processing.

The pig iron can be further refined to produce steel or wrought iron. Both these methods reduce the carbon content of the pig iron, which in turn reduces the brittleness property of the metals.Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Wrought Iron ProcessWrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Wrought iron is produced by pummeling the pig iron using mechanically driven hammers in a wrought iron works. This process prepares it for the next stage which is the heating and forging to the desired wrought iron designs and shapes.

This used to be an art of the blacksmith, but is now normally carried out by machines.Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Steel ProcessThis process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

This process is used to remove impurities from the pig iron produced in a blast furnace. It has developed from the early methods used such as an open hearth, or a Bessemer furnace. Today we normally use an Electric Arc Furnace (EAF) or a Basic Oxygen Furnace. (EAF)

Both methods remove a high percentage of the carbon content from the pig iron, along with the impurities of aluminum, calcium (produced during tapping), sulphur, silicon, manganese, and phosphorus.Electric Arc Furnace (EAF)The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

The vertical circular steel furnace is brick-lined and has a roof which contains graphite electrodes. The electrodes are withdrawn and the roof is lifted to facilitate the loading of the pig iron to the bottom of the furnace. This is followed by a known quantity by scrap steel, which is dependent on the final grade of steel required.Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Once the roof is replaced, the electrodes are lowered and an initial voltage is applied to them, and when the scrap steel has started to melt, the main voltage is applied.When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

When the metal is molten, oxygen is injected into it, with the impurities being converted to oxides and forming a slag. The oxygen also reacts with the carbon forming CO which is combusted adding heat to the process. Oxygen injection also reduces the carbon, nitrogen and hydrogen content on completion of the process, samples are taken and analyzed, and if acceptable, steel with content of up to 1% of carbon is poured into ingots.Basic Oxygen Furnace (BOF)If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

If the furnace has been designed to be linked to the blast furnace process, molten iron is carried in crucibles and poured into the BOF. This is a much more efficient method of removing the bulk of carbon and impurities rather than using solid pig ironThe crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

The crucible of molten iron can undergo pretreatment by the injection of magnesium, iron oxide to remove the sulphur, phosphorus, and silicon, or these impurities can be removed during the BOF process.The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

The BOF furnace is filled up to 20% scrap steel, and then the molten iron is poured into the furnace from the crucible.Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Oxygen is injected through a water cooled steel lance into the molten metal promoting the same effects as in the EAF steel processing system.Iron and Steel Smelting Process Sketches.Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

Internet Sites Visitedhttps://www.chemguide.co.uk/inorganic/extraction/iron.htmlhttps://www.thepotteries.org/shelton/blast_furnace.htmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=21171&TEMPLATE=/CM/ContentDisplay.cfmhttps://www.steel.org/AM/Template.cfm?Section=Articles3&CONTENTID=12306&TEMPLATE=/CM/ContentDisplay.cfm

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iron & steel | yokogawa philippines

iron & steel | yokogawa philippines

In the iron and steel industry, it is crucial to improve the quality of not only products but also manufacturing and operation technologies, as well as to address environmental and energy-efficiency issues. Yokogawa helps customers to create the ideal plant and evolves with them for mutual growth.

Yokogawa helps leading-edge Iron and Steel plants through automation solutions that enable plant-wide integration and lifecycle optimization. Here is a quick list of Iron Making units and applications for which Yokogawa has a global network of experts at your service, providing comprehensive automation solutions.

Yokogawa helps leading-edge Iron and Steel plants through automation solutions that enable plant-wide integration and lifecycle optimization. Here is a quick list of Steel Making units and applications for which Yokogawa has a global network of experts at your service, providing comprehensive automation solutions.

Yokogawa helps leading-edge Iron and Steel plants through automation solutions that enable plant-wide integration and lifecycle optimization. Here is a quick list of Rolling Mill units and applications for which Yokogawa has a global network of experts at your service, providing comprehensive automation solutions.

Yokogawa helps leading-edge Iron and Steel plants through automation solutions that enable plant-wide integration and lifecycle optimization. Here is a quick list of Surface Finishing units and applications for which Yokogawa has a global network of experts at your service, providing comprehensive automation solutions.

Yokogawa helps leading-edge Iron and Steel plants through automation solutions that enable plant-wide integration and lifecycle optimization. Here is a quick list of Utility units and applications for which Yokogawa has a global network of experts at your service, providing comprehensive automation solutions.

First generation CENTUM had contributed to the production of high-quality steel product at the NSSMC's Yawata Works for 33 years. Yokogawa had pursued innovation of process control technology with the customer during the decades.

The Japan Steel Works, LTD., Muroran Plant uses the Control and Measurement Station CX2000, UP series program controllers, and UT series digital indicating controllers for operation of its heat treating furnaces.The Japan Steel Works (JSW), LTD., Muroran Plant is located in an industrial area looking over Muroran port in Muroran City, Hokkaido.

In a hot blast stove, the by-product gas produced in a coke oven is burned to preheat the air blast for the blast furnace. To improve the combustion efficiency and conserve energy in a hot blast stove, it is essential to be able to control combustion by measuring and adjusting the oxygen concentration in the exhaust gases.

A furnace for heating slabs needs to be operated under low oxygen conditions at high temperatures of 1000C and above to prevent oxidation of the steel. The measurement of oxygen concentrations in the furnace is essential in this process. (AN 10M01F01-03E)

To technology in iron & steel industry is continuously improved to obtain the best possible performance. The improved plant performance gives rise to the higher quality improvement and lower cost, and simultaneously environmental friendly plant operation.

The world of process automation is governed by procedures. While we like to refer to the process industries as being largely "continuous", this could not be further from the truth. Process manufacturing is constantly in flux.

The automation suppliers that will be successful in the long term will be those that effectively address application or industry specific problems for end users with a value proposition that cannot be ignored. These problems exist throughout the process industries today, and they won't be solved by simply offering a product, but through a combination of hardware, software, services, application expertise, and knowledge.

Yokogawa has come a long way in making its message clear to the world of process automation. Last year, the company embarked on a full-scale global marketing campaign to make customers aware of the company's focus on system reliability, security, dependability, and robustness. Dubbed "Vigilance", the campaign created a unified message for the company and greatly helped expand awareness of the Yokogawa brand and corporate philosophy.

Process automation end users are under more pressure than ever to do more with less. The current economic climate means that many automation capital projects are on hold. With capital budgets tighter than ever, users instead focus on operational budgets (where cost cutting is also a key concern), or on automation investments with a very rapid return on investment.

In today's dynamic industrial marketplace, the only constant is change. Raw material costs, energy costs, market demands, environmental and safety regulations, technology, and even the nature of the labor force itself are constantly changing, and not always in predictable directions.

Honeywell and Yokogawa have both been producing Distributed Control System (DCS) platforms for decades, and both are very active in this area. In 1975, Honeywell introduced its TDC2000 platform and Yokogawa brought out CENTUM. These two competing systems emerged from a similar place, oil refining and petrochemical industries, so they started out with similar basic concepts and use cases in mind.

The YSS1000 setting software (hereinafter referred to as the YSS1000) is package software to configure the functions of the YS1000 series (hereinafter referred to as the YS1000) devices. Writing and reading of parameters and user programs of the YS1000, and PID tuning and monitoring of user programs can be performed through the use of communication.

iron ore grinding process,process design for grinding stage,closed circuit grinding technology | prominer (shanghai) mining technology co.,ltd

iron ore grinding process,process design for grinding stage,closed circuit grinding technology | prominer (shanghai) mining technology co.,ltd

Generally, the conventional process can be applied except for ore with a lot of mud and high humidity. The self-grinding and semi-self-grinding processes have high power consumption and should be selected carefully.

There is no strict restriction on the upper limit and particle size distribution of the products in the open-circuit grinding process. Because the ore to be ground passes through the grinding machine only once, the product size is relatively coarse. This type of process is commonly used in the first stage of the single-stage rod milling process or the first stage of the two-stage grinding process with rod mills. The ore can be ground from 20-25 mm to about 3 mm at a time. The open-circuit grinding process is simple, the production capacity is large, no grading and return ore facilities are required, the construction speed is fast, the production operation and maintenance are easy, and it is generally used for rough grinding.

In closed-circuit grinding, the returned sand from the classifier is mostly finer than the original ore. The returned sand is mixed with the ore newly fed into the mill, so that the average particle size of the ore particles in the mill is reduced, and the content of ore particles close to the particle size of the grinding product increases. The gap around the coarse-grained ore is filled with fine-grained sand. It is beneficial to form a more favorable meshing between the crushing medium and the ore particles. Along the entire length of the grinding machine, the ratio of the size of the ball to the average diameter of the ore particles is relatively stable. The material flows faster in the grinding machine. Therefore, the productivity of the closed-circuit grinding machine is generally higher than that of the open-circuit grinding machine, and the product size is smaller. Fine, uniform particle size, less over-crushing. Closed-circuit grinding can also improve the selective grinding of heavy minerals.

The beneficiation practice shows that in each grinding section, the grinding ratio has a suitable value, and the grinding ratio of the conventional ball milling section is generally about 80-100. An excessively large primary grinding ratio is uneconomical. The grinding efficiency is low, the energy consumption is high, and the product is easily crushed, which affects the sorting effect and economic benefits. Practice has shown that the more difficult to grind the ore, the less economically reasonable it is to use one-stage grinding process for fine grinding. The two-stage grinding process can overcome the shortcomings of the one-stage grinding process. It can reasonably distribute the load according to the difference in the particle size of the materials in the grinding mills and the properties of the wear-resistant materials, and it is easy to select the appropriate medium size and ratio according to the different feed and product particle sizes of the two-stage mills.

When the grindability of the ore is very poor and the grinding particle size is required to be extremely fine, or the concentrate grade is required to be high and the ore is fine-grained or unevenly embedded, or the old concentrator wants to improve the original grinding When operating the production capacity, three-stage or multi-stage grinding process can be used. For ore that is extremely easy to slush, in order to improve the efficiency of grinding and beneficiation, prevent excessive crushing, and recover the dissociated useful minerals as soon as possible, the stage grinding and stage separation process can be used. In this way, the use of selective grinding can effectively recover useful minerals. Large-scale iron ore concentrators that adopt a staged grinding process can sort and discard coarse-grained tails after one stage of grinding if the iron ore properties are suitable.

Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.

sinter plant - an overview | sciencedirect topics

sinter plant - an overview | sciencedirect topics

Sinter plants are the major contributor to dust emissions from integrated ironworks and steelworks. The dust emissions from sinter plants are generated from raw material handling, wind box exhausts, the discharge end of the sinter strand associated with sinter crushers and hot screens, the cooler, and cold screens. The wind box emissions represent about 60% of the total particulate emissions from the sinter plant, followed by discharge end emissions. As legislated limits become more and more stringent, sinter plants are under increasing pressure to further decrease emissions. One of the best available techniques for dedusting is the use of electrostatic precipitation plus fabric filter to remove particulate matter, which is associated with particulate matter emission concentrations of 1020mg/m3 (UK Environment Agency, 2004). Other dedusting options that are commonly used for sinter plant off-gases include ESPs and wet scrubbers, but particulate removal efficiency is not as high as for fabric filters. ESPs and high-efficiency wet-gas scrubbers perform well with particulate matter concentrations of 3050mg/m3 (William Lemmon and Associates Ltd., 2003). In addition to the control of dust emissions from the wind boxes, adequately sized capture and dedusting controls for both the feed and discharge ends of the sinter strand should be put in place. Crusher and hot screen emissions are usually controlled by hooding with a baghouse or scrubber, while emissions generated from other material handling operations are captured and vented to a baghouse.

Attention will be focussed on the sinter plant, Figure 1, only since energy usage in the materials storage, conveying and proportioning plant is small relative to the energy effects of the sintering process.

It is evident from table 4 that the thermodynamic efficiency of the sinter plant calculated according to equation 7 is 45.1%. The product gases represent the principal exergy flow from the plant, 20 MJs1; of this 92% is due to the SO2 content. These gases pass to the Acid Plant. The output sinter passes to the Blast Furnace.

The absence of coke ovens and sinter plants in the FINEX process allow the capital investment of the FINEX to be reduced 20% compared to a conventional BF. Without cokemaking and sintering, the FINEX is more compact and takes less space. Continued cost advantages during operation can be realized as low cost and low quality raw materials (high alumina ore, high zinc ore, noncoking coals) use outweigh its counterpart routes. Unlike the BF, there are no burden control issues and shut-down and start-up is comparatively simpler than the conventional route. The relative capital costs associated with the FINEX compared to the conventional BF is provided in Figure 4.5.75.

Typical operating costs of the FINEX is estimated to be approximately 15% lower than the conventional BF route although higher costs are apparent from using un-preheated pure oxygen and higher input coal rates.

Environmentally, the FINEX operation has shown SOx, NOx, dust, and CO2 emissions to be significantly reduced compared to the BF. The sulfur contained in the gas from coal combines with some of the hydrocarbons in the coal forming H2S and S2 gases, which can effectively react with the CaO in the limestone forming CaS in the meltergasifier. Due to the higher exit-gas temperature of the FINEX process and the higher CO gas concentrations in the fluidized beds, the formation of SOx gases is likely limited. NOx emissions are almost eliminated because the coal reaction takes place with pure oxygen in the reducing atmosphere of the meltergasifier, unlike the hot air used in the BF. Dust emissions are also reduced due to the elimination of the sintering process and the efficiency of the cyclone (Figure 4.5.76).

Similar to sintering, pelletizing is another widely used process to agglomerate the iron ore. Sinter plants are usually located near the blast furnace plant, but pelletizing plants are often located near the mining site. Some works have both pelletizing and sintering plants at the smelter sites.

The ore is crushed, ground, and concentrated in several steps to very small grain sizee.g., over 75% less than 45m. Binder (bentonite or organic) and possible additives are fed in the slurry and mixed before filtering. The filter cake is transported to large balling drums or balling discs to be rolled to green pellets. The green pellets are screened to 911mm diameter. The oversize is crushed and fed together with the undersize back to balling.

The process to harden pellets by heating them up to the sintering temperature is called induration. There are three induration processes: Grate-Kiln, Straight Grate, and Vertical Shaft furnace, of which the first two are dominating whereas the shaft furnace is retreating. Figure 1.1.11 illustrates a typical pellet firing process [22].

In Grate-Kiln process, green pellets are fed on oil or gas-fired endless Straight Grate machine where they are dried and preheated. The preheated pellets are then fed to a rotary kiln where their temperature is raised in oxidizing atmosphere to 12901400C. In induration, ore grains are sintered together with oxidation and slag-forming bonds. Pellets are cooled in a separate cooler. In Straight Grate process drying, preheating, induration, and cooling take place on the same endless grate machine. In both processes, heat from later process steps is circulated back to preceding steps by hot air with a duct and fan system.

Similar to sinter, the following properties are important for pellets: cold strength, reductiondisintegration, the swelling properties, melting, and softening. The reductiondisintegration property of pellets are of less concern compared to sinter. However, pellets have more tendency of swelling than sinter and lumpy ore. Swelling occurs during the transformation of wstite to metallic iron. Figure 1.1.12 illustrates typical iron ore pellets [22].

The total energy use distribution [24] by various units of the steel plant (coke ovens, sinter plant, blast furnaces, steel shop, rolling mills, and power plant) is shown in Figure 4.2.8. It can be noted that the major share (72%) of energy is required during iron making which includes coke making (12%), iron ore sintering (6%), and blast furnaces (54%). The steel making needs very little share (4%) as the process is exothermic in nature. The thermal energy used in power generation and hot rolling account for 8% and 11%, respectively. The cold rolling needs 5% energy mainly as electricity.

The total energy input is partly (52%) used to meet chemical, thermal, and process needs of the plant and the rest (48%) is wasted. This energy used and wasted is illustrated [24] in Figure 4.2.9. The efforts are made to recover the waste heat to improve the efficiency of the process. The amount of sensible heat available [25] in various units is indicated in Figure 4.2.10.

After acceptance of the revised Detailed Project Report, in February 1981, a contract was signed with USSR for preparation of working drawings for coke ovens, blast furnace and sinter plant. The blast furnace foundation was laid with 1st mass concreting in the project in January 1982. The construction of township also started. But SAIL, the original holding company of VSP was finding it very difficult to manage the construction of VSP along with its regular operation of its five other integrated steel plants (ailing Indian Iron and Steel Co. was taken over by SAIL in 1972). Under these circumstances, Government of India, on February 18, 1982 formed a new Company called Rashtriya Ispat Nigam Limited (RINL) and transferred the responsibility of constructing, commissioning and operating the plant at Visakhapatnam from SAIL to RINL.

Similar to ISO 3271, the Japanese Standards Association has developed a standard called the shatter test, JIS M8711:2011, to access the degradation of iron ore sinter due to drop during transportation from the sinter plant to the BF. In accordance with JIS M8711, the shatter index (SI) is determined as the weight percentage of +10mm material remaining after four drops of a 20kg sized sinter sample (50+10mm) from a height of 2m. Unlike ISO 3271, the shatter test only simulates the degradation of sinter due to drops during transportation from the sinter plant to the BF.

Iron ore is used directly in the steelmaking process in the blast furnace in the form of lump, pellet, and fines (see Fig. 5). (Fines are converted to sinter feed in a sinter plant.) Iron ore pellets are also used in the production of DRI and HBI.

Iron ore consumption will grow globally, though most rapidly in developing countries and particularly in the form of pellets. The incremental growth will most likely be greatest in regions other than Western Europe and communist countries other than China and FSU. A significant portion of the newly developed iron ore will be consumed in the form of pellets for blast furnace or DRI feed. DRI production will consume more than 70% of the incremental pellets consumed over the next 25 years, while blast furnaces will consume the remainder. Other Asia, other Western World, and Central and Latin America will see the largest growth in iron ore pellet use for DRI or HBI.

The global best available technology (BAT) has a benchmark of primary SEC of 16.4GJ/tcs through BFBOF route, 19.3GJ/tcs by the smelt reduction (COREX)BOF route, 19.1GJ/tcs through coal-based DRI-EAF route, and 15.9GJ/tcs from gas-based DRI-EAF route in 2009. In India, the average primary SEC from selected major steel plants was 27.3GJ/ton of crude steel. There is potential for improvement in SEC after adjusting for limitations in the availability and quality of iron ore and coking coal [2].

Energy cost is a major component of the manufacturing cost and ranges between 40% and 60% in a typical iron and steel plant. The iron and steel sector comprises different subsectors such as the large ISPs, mini-blast furnace plants, coal- or gas-based DRI SI plants, and steel production through electric furnaces. There is vast variation in the sector with regard to scale, technology, vintage, quality of raw materials and products, and in other operating conditions. The large ISP sector has been consistently working toward reducing the energy and emissions intensity subject to financial constraints; however, much remains to be done to assist the smaller plants toward such a roadmap.

There are several energy efficiency measures that have either already been adopted or could be adopted by the industry. However, the actual set of measures that is suited for a particular Designated Consumer would be based on the specific operating conditions.

Energy efficiency technologies1.Sintering1.Heat recovery from sinter cooler2.Reduction of air leakage3.Increasing bed depth4.Use of waste fuel in sinter plant5.Improved charging method2.Coke making1.Coal moisture control2.Programmed heating in coke oven3.Variable speed drive on coke oven gas compressors4.Coke dry quenching3.Iron makingblast furnace1.Injection of pulverized coal in BF2.Injection of natural gas in BF3.Injection of oil in BF4.Injection of plastic waste in BF5.Injection of coke oven gas in BF6.Top-pressure recovery turbines7.Recovery of blast furnace gas8.Improved blast furnace control9.Improved hot blast stove control4.Steelmakingbasic oxygen furnace (BOF)1.Recovery of BOF gas and sensible heat2.Variable speed drive on ventilation fans3.Efficient ladle preheating5.SteelmakingEAF1.Converting the furnace operation to ultra-high power (increasing the size of transformers)2.Adjustable speed drives on flue gas fans3.Oxy-fuel burners/lancing4.Improving process control in EAF5.Direct current (DC) arc furnace6.Scrap preheating7.Bottom stirring/gas injection6.Casting1.Integrated casting and rolling (strip casting)7.Hot rolling1.Recuperative or regenerative burner2.Flameless oxy-fuel burners3.Controlling oxygen levels and variable speed drives on combustion air fans4.Insulation of reheat furnaces5.Hot charging6.Process control in hot rolling7.Waste heat recovery from cooling water8.Cold rolling1.Continuous annealing2.Heat recovery on the annealing line3.Reduced steam use in the acid pickling line4.Automated monitoring and targeting systems9.General measures1.Preventative maintenance in integrated steel mills2.Preventative maintenance in EAF plants3.Energy monitoring and management systems in integrated steel mills4.Energy monitoring and management systems in EAF plants5.Variable speed drives for flue gas control, pumps, fans in integrated steel mills6.Cogeneration for the use of untapped coke oven gas, blast furnace gas, and BOF gas in integrated steel mills

Iron makingblast furnace1.Injection of pulverized coal in BF2.Injection of natural gas in BF3.Injection of oil in BF4.Injection of plastic waste in BF5.Injection of coke oven gas in BF6.Top-pressure recovery turbines7.Recovery of blast furnace gas8.Improved blast furnace control9.Improved hot blast stove control

SteelmakingEAF1.Converting the furnace operation to ultra-high power (increasing the size of transformers)2.Adjustable speed drives on flue gas fans3.Oxy-fuel burners/lancing4.Improving process control in EAF5.Direct current (DC) arc furnace6.Scrap preheating7.Bottom stirring/gas injection

Hot rolling1.Recuperative or regenerative burner2.Flameless oxy-fuel burners3.Controlling oxygen levels and variable speed drives on combustion air fans4.Insulation of reheat furnaces5.Hot charging6.Process control in hot rolling7.Waste heat recovery from cooling water

General measures1.Preventative maintenance in integrated steel mills2.Preventative maintenance in EAF plants3.Energy monitoring and management systems in integrated steel mills4.Energy monitoring and management systems in EAF plants5.Variable speed drives for flue gas control, pumps, fans in integrated steel mills6.Cogeneration for the use of untapped coke oven gas, blast furnace gas, and BOF gas in integrated steel mills

The total sensible heat recovery possible from ISP is 5.53GJ/trs out of which 4.88GJ/trs is commercially practiced globally. DRI rotary kilns also have a large waste heat recovery potential from the heat radiated by the kiln and sensible heat carried out by cooler and exhaust gases.

The use of alternate materials such as waste plastics and natural gas as reducing agents can significantly reduce the emissions intensity of the iron and steel sector while contributing to reductions in SEC as in the case of natural gas.

The presence of CDD/CDFs has been documented in practically all media including air, soil, meat, milk, fish, vegetation, and human biological samples (Travis and Hattemer-Frey, 1991). The widespread occurrence of these persistent compounds is likely the result of atmospheric dispersion and deposition of particles resulting from combustion processes, from forest fires to waste incineration to auto exhaust. CDD/CDFs are also unwanted by-products in the manufacture of chlorinated organic compounds such as herbicides and wood preservatives.

The environmental forensic scientist investigating the potential sources of CDD/CDFs must understand the wide variety of sources as well as the range of normal background concentrations that would be expected in environments similar to those being evaluated. The purpose of this section is to provide a summary of sources and to present a range of background concentrations reported in environmental media.

There have been many excellent literature reviews and compilations of CDD/CDF sources (e.g., Fiedler et al., 1996; Rappe, 1994; US EPA, 1997, 2000, 2003). US EPA (2005) at the time of writing had updated their Inventory of sources and environmental releases of dioxin-like compounds in the United States with data through the year 2000. This is the most comprehensive resource of CDD/CDF sources currently available, with more than 800 references cited, although at the time of this writing the document was available only as an external review draft and the final report may include additional data provided during the peer review and public comment process. The final report and future updates will be posted on EPA's National Center for Environmental Assessment (NCEA) Web site (http://cfpub.epa.gov/ncea/).

The ranking of sources from the 1987, 1995, and 2000 inventories is shown in Figure 14.3.1. The number one category in 2000 was emissions from backyard burn barrels (US EPA, 2005), accounting for approximately 32% of estimated emissions, followed by medical waste incinerators (24%) and municipal waste combustors (5%).

The EPA also maintains a downloadable database of CDD/CDF sources (Table 14.3.1) on the NCEA website. The availability of this electronic database is a valuable resource for source identification studies, but the primary articles should be obtained and reviewed so that the original data can be evaluated for variability of profiles, handling of detection limits, and potential problems (e.g., coelution of isomers in older data sets). Several of the key source categories are discussed later with an emphasis on combustion.

CDD/CDFs can be formed during various types of ferrous and non-ferrous smelting (both primary and secondary). US EPA (2005) provides congener profiles for emissions from secondary aluminum, copper, and lead smelters, iron ore sinter plants, a scrap wire incinerator, and a drum incinerator.

Trace amounts of CDD/CDFs can form as by-products from the manufacture of chlorine-bleached wood pulp, chlorinated phenols (e.g., pentachlorophenol [PCP]), PCBs, phenoxy herbicides (e.g., 2,4-dichlorophenoxyacetic acid [2,4-D] and 2,4,5-trichlorophenoxyacetic acid [2,4,5-T]), and chlorinated aliphatic compounds (e.g., ethylene dichloride). Congener profiles are provided in US EPA (2005) for pulp, sludge, and effluent from mills using chlorine bleach process, for technical grade PCP, for 2,4-D salts and esters, and for sewage sludge.

Combustion is the primary source of CDD/CDFs to the global environment. CDD/CDFs are generated in waste incineration (e.g., municipal solid waste, sewage sludge, medical waste, and hazardous wastes), fuel combustion (e.g., oil, gasoline, diesel, coal, and wood), other high-temperature sources (such as cement kilns), and poorly controlled or uncontrolled combustion sources (e.g., forest fires, building fires, and open burning of wastes).

Cleverly et al. (1997) reported that combustion sources typically emit all 2,3,7,8-substituted CDD/CDFs, although the relative congener concentrations vary. These authors found that 2,3,7,8-TCDD is usually 0.1 to 1% of total CDD/CDFs in combustion source emissions, with the exception of stack emissions from industrial oil-fired boilers, where the available data indicate that 2,3,7,8-TCDD constitutes an average of 7% of total CDD/CDF emissions.

In evaluating congener profiles for the EPA inventory of sources, Cleverly et al. (1997) noted that OCDD is the dominant congener in some, but not all, combustion emissions. OCDD dominates emissions from mass-burn municipal waste combustors (MWCs) that have dioxin emission controls. It also dominates emissions from industrial oil-fired boilers, industrial wood-fired boilers, unleaded gasoline combustion, diesel fuel combustion in trucks, and sewage sludge incinerators. These authors reported that the dominant congeners for other combustion sources are 1,2,3,4,6,7,8-HpCDF in emissions from mass-bum MWCs equipped with hot-sided electrostatic precipitators, hazardous waste incineration, and secondary aluminum smelters; OCDF in emissions from medical waste incineration and industrial/utility coal-fired boilers; 2,3,4,7,8-PeCDF in cement kilns burning hazardous waste; and 2,3,7,8-TCDF in cement kilns not burning hazardous waste.

Congener profiles for the following combustion sources are provided in US EPA (2005): MWC, medical waste incinerators, furnaces burning hazardous waste, crematoria, sewage sludge incinerators, a tire combustor, vehicle exhaust, wood combustion, power boilers (coal, wood, and oil), cement kilns (burning hazardous and non-hazardous waste), petroleum catalytic reformer units, black liquor recovery boilers, cigarette smoke, landfill flares, and forest fires.

Open burning of yard waste and household trash is not only the number one source of CDD/CDFs in the national inventory (US EPA, 2005), but can also be a source of locally elevated CDD/CDFs immediately downwind from the burn barrel (MOEP 1997; Wevers et al., 2003). CDD/CDF source identification studies in rural communities should include emissions from backyard burning as a potentially significant cause of elevated CDD/CDF concentrations in soils and house dust.

Unlike combustion of diesel or municipal solid waste in a controlled incinerator, the types of waste and combustion conditions in a backyard burn barrel are extremely variable. Therefore, it is difficult to predict what the CDD/CDF concentrations and profile would be in the surface soils or indoor dust of a house next to a burn barrel or a burn pit.

Available studies of CDD/CDF congeners in emissions from backyard burning (Ikeguchi and Tanaka, 2000; Gullet et al., 2001; Lemieux et al., 2003; Wevers et al., 2003; Gnczi et al., 2005; US EPA 2005) indicate a wide range of congener patterns and more than four orders of magnitude range of TEQ concentrations. For example, in Wevers et al. (2003), the congener patterns for burning garden waste and household waste were both dominated by OCDD and HpCDD, but the household waste emissions were also characterized by high relative concentrations of the low to mid-weight CDFs and one HpCDF. In contrast, the profiles from Lemieux et al., (2003) were very low in OCDD and HpCDD.

According to Lemieux et al. (2003), [m]any possible parameters could have a significant influence on CDD/CDF emissions from burn barrels. Many of these parameters could be caused by variations in practice-related variables that would vary from homeowner to homeowner. Some of these parameters include physical condition of waste in the barrel (e.g., fullness of the barrel, degree of compression of the waste, distribution of waste components within the barrel), chemical composition of the waste (e.g., wetness, trace metal content, Cl content, organic vs. inorganic Cl), and combustion conditions resulting from variations in the previously mentioned physical and chemical characteristics.

In the US EPA (2005) review of burn barrel data, the authors state that the wide variability in test results (from less than 10 to more than 6000 ng I-TEQDF/kg) also indicates that a high degree of CDD/CDF emission variation can be expected due to factors that are not wholly related to waste composition or burning practice, such as waste orientation.

One of the first steps in CDD/CDFs source evaluation studies is to determine if the concentrations in the media of concern are actually above background levels. Site-specific background samples are always preferred, but often unavailable. If site-specific background data are not available, the concentrations need to be compared to published values. US EPA (2003) provides a comprehensive review of background data for soil, sediment, ambient air, water, fish tissue, and a variety of food items as summarized in Table 14.3.2. In addition, background data for indoor house dust from urban neighborhoods (Berry et al., 1993; Wittsiepe et al., 1996; Saito et al., 2003) indicate a WHO-TEQ range of 2.1270 ng/kg for 27 samples, with an arithmetic mean of 45 ng/kg (undetected results set to one half the detection limit). It is important to note that domestic laundry activities (e.g., dryerlist) can be an important source of CDD/Fs in indoor house dust.

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