Aggregate production line for railways and engineeringApplications of Aggregate production line for railways and engineering:1.Aggregates with grain size larger than 5mm are called coarse aggregates, and there are two kinds of gravel and pebble commonly used. Particle size grading: 5-10,10-20,20-31.5.2.The aggregate with the grain size below 5mm is called fine aggregate. According to theproduction of sand is divided into natural sand and machine-made sand.3.Aggregates as the main raw material in concrete because of its good hardness and stability of chemical properties ,It is play a role of the skeleton and support in the building. Widely used in housing, roads, roads, railways, engineering and other fields.4.Aggregate production lines can be used for hard limestone, granite, basalt, river gravel, smelting slag and other materials, aggregate and artificial sand making operations,for Hydropower Station, building materials, highways, urban construction and other industries.5.According to different process requirements, various types of equipment combined to meet customer's different process requirements.Brief introduction of Aggregate production line for railways and engineering:1.Aggregate production can be simply summarized as crushing and sorting, mainly from the conveyor, feeding, crushing, screening, sand and other aspects of aggregate production line introduced aggregate. 2.The choice of crushing equipment depends on the characteristics of ore raw materials, the local market demand for gravel products and production capacity of the production line.3.Aggregate production line production process is as follows:a.Large stone by the silo by the vibrating feeder evenly sent to the jaw crusher for coarse crushing, coarse crushed stone by the conveyor belt to the impact crusher for further crushing.b.Crushed stone by the belt conveyor Sent to the vibrating screen for screening, screening out several different specifications of the stone, meet the requirements of the size of the stone conveyor belt conveyor, the finished product sent to finished heap.c.Do not meet the requirements of stone by the conveyor belt back to the impact crusher to break again to form closed-loop multiple cycles. d.Finished particle size can be combined in accordance with the needs of users and grading, to protect the environment, can be equipped with auxiliary dust removal equipment.1.Vibrating feeding equipmentThis type of vibrating feeder can continuously feed the material to the crusher continuously and make rough screening of the materials. 2.Crusher1.According to the broken principle can be divided into two categories: extrusion crusher and impact crusher. Extrusion crusher (such as gyratory crusher, jaw crusher, cone crusher) is suitable for rock with high hardness and abrasive index (such as granite, quartz, diabase, basalt). 2.Impact crusher (such as the impact crusher, vertical shaft crusher, hammer impact crusher) to adapt to the hardness, abrasion index medium or low rock (such as limestone, dolomite, etc.).1) jaw crusherprimary crushing of hard rocks and block materials2) impact crusher3) PYFB-1324 Composite cone crusherPYFB-1324 compound cone crusher used in mining, cement, sand and gravel industry, for medium, fine broken, the pressure of 350 MPa in the following mine rocks, such as iron ore, non-ferrous metal ore, basalt, granite Limestone, sandstone, pebble stool. 3.Circular screen/vibrating screen---sieve the crushed stone into different sizes4.Sand making equipment---Mainly vertical shaft sand or rod mill.1) Vertical axis form of sand making machineSand making machine is widely used in a variety of fine ore broken. Sand making machine is widely used in medium and fine crushing fields of various hard and special hard materials such as ore, cement, refractory material, bauxite clinker, emery, glass raw material.2) Rod millRod mill is mainly used for preparation of sand. The material is raised to a certain height, falling state was dropped, the need for grinding of the material from the feeding Department of continuous into the cylinder, the grinding of the grinding medium is moving, and through the overflow and the power of continuous feeding the product out of the machine for the next processing step.3) Screw classifierScrew classifier used for the production of gravel in the process of particle size grading, and used in conjunction with mining machinery. Screw classifier Widely used in the ore dressing and ball mill with a closed loop, diversion of ore, or for gravimetric ore in the classification of ore and fine mud, and metal mineral processing process for particle size grading, and washing operations in the deslimation, dehydration and so on. The spiral classifier has the characteristics of simple structure, reliable operation and convenient operation. Also used for gravel operations in the deslimation or dehydration.Advantages of Aggregate production line for railways and engineering:a.The shape of the final product, with excellent quality.b.Mud and powder content can be controlled. c.This sand production line has the characteristics of high automation, low operating cost, high crushing rate, high productivity, and little pollution, etc. It is energy saving and is convenient to maintain.d.Sand made by our sand production line is of equal size, good shape and reasonable distribution, complying with national building sand standard.e.Due to reasonable matching of different levels of crushing machines and compact spatial arrangement, our crushing and screening plant has the features of small floor space, high economic efficiency. The crushed stones are of high quality, and the output rate of stone powder is low.f. Meanwhile, our sand production line is equipped with electronic control system which ensures smooth discharging, reliable performance, high efficiency and energy conservation.g.Our senior engineers design each production line according to different customers.WINNER GROUP Sand Making Production Line Main Equipment Model/Specification/Quantity:Maximum Feeding Size(mm)Capacity(t/h)Vibrating FeederJaw CrusherFine Crushing Equipment (Impact Crusher)Vibrating ScreenConveyor Equipment(m)Installed Power(KW)34030GZD2511(3kw)PE400600(30kw)PF1007(45kw)3YZ1236(15kw)60-90(20kw)12034050GZD3117(10kw)PE400600(30kw)PF1007(45kw)3YZ1545(22kw)100-130(30kw)14042080GZD3617(10kw)PE500750(55kw)PF1010(75kw)3YZ1548(22kw)130-160(30kw)200480100GZD4321(13kw)PE600900(75kw)PF1210(130kw)3YZ1548(22kw)140-180(40kw)280560150GZD4321(13kw)PE7501060(90kw)PF1210(130kw)3YZ1845(22kw)200-240(50kw)300630200GZD4321(13kw)PE9001060(110kw)PFB1212(140kw)3YZ2050(30kw)200(40kw)350630250GZD5027(17kw)PE9001060(110kw)PFB1214(180kw)3YZ2050(30kw)200(40kw)400630300GZD5027(17kw)PE9001200(110kw)PFB1214(180kw)3YZ2160(30kw)250(50kw)450700350GZD5027(17kw)PE10001200(132kw)PFB1315(250kw)3YZ2160(30kw)250(50kw)500700450GZD6223(28kw)PE10001200(132kw)PFB1214/2(300kw)3YZ2145/2(60kw)350(60kw)600If you want the stone production line, please tell me: 1) the raw stone material you want to crush2) the raw stone material size3) the final discharging size you request. 4) the capacity.
3.Aggregates as the main raw material in concrete because of its good hardness and stability of chemical properties ,It is play a role of the skeleton and support in the building. Widely used in housing, roads, roads, railways, engineering and other fields.
4.Aggregate production lines can be used for hard limestone, granite, basalt, river gravel, smelting slag and other materials, aggregate and artificial sand making operations,for Hydropower Station, building materials, highways, urban construction and other industries.
1.Aggregate production can be simply summarized as crushing and sorting, mainly from the conveyor, feeding, crushing, screening, sand and other aspects of aggregate production line introduced aggregate.
b.Crushed stone by the belt conveyor Sent to the vibrating screen for screening, screening out several different specifications of the stone, meet the requirements of the size of the stone conveyor belt conveyor, the finished product sent to finished heap.
1.According to the broken principle can be divided into two categories: extrusion crusher and impact crusher. Extrusion crusher (such as gyratory crusher, jaw crusher, cone crusher) is suitable for rock with high hardness and abrasive index (such as granite, quartz, diabase, basalt).
PYFB-1324 compound cone crusher used in mining, cement, sand and gravel industry, for medium, fine broken, the pressure of 350 MPa in the following mine rocks, such as iron ore, non-ferrous metal ore, basalt, granite Limestone, sandstone, pebble stool.
Sand making machine is widely used in a variety of fine ore broken. Sand making machine is widely used in medium and fine crushing fields of various hard and special hard materials such as ore, cement, refractory material, bauxite clinker, emery, glass raw material.
Rod mill is mainly used for preparation of sand. The material is raised to a certain height, falling state was dropped, the need for grinding of the material from the feeding Department of continuous into the cylinder, the grinding of the grinding medium is moving, and through the overflow and the power of continuous feeding the product out of the machine for the next processing step.
Screw classifier used for the production of gravel in the process of particle size grading, and used in conjunction with mining machinery. Screw classifier Widely used in the ore dressing and ball mill with a closed loop, diversion of ore, or for gravimetric ore in the classification of ore and fine mud, and metal mineral processing process for particle size grading, and washing operations in the deslimation, dehydration and so on. The spiral classifier has the characteristics of simple structure, reliable operation and convenient operation. Also used for gravel operations in the deslimation or dehydration.
c.This sand production line has the characteristics of high automation, low operating cost, high crushing rate, high productivity, and little pollution, etc. It is energy saving and is convenient to maintain.
e.Due to reasonable matching of different levels of crushing machines and compact spatial arrangement, our crushing and screening plant has the features of small floor space, high economic efficiency. The crushed stones are of high quality, and the output rate of stone powder is low.
Dewo machinery can provides complete set of crushing and screening line, including Hydraulic Cone Crusher, Jaw Crusher, Impact Crusher, Vertical Shaft Impact Crusher (Sand Making Machine), fixed and movable rock crushing line, but also provides turnkey project for cement production line, ore beneficiation production line and drying production line. Dewo Machinery can provide high quality products, as well as customized optimized technical proposal and one station after- sales service.
Scrap shredder parts | Sinco. Scrap shredder wearing parts. Sinco also manufacture wear-resistant castings parts for metal shredder and scrap metal recycling machine, these parts including grate bar, reject door, pin protect, shredder anvils and cap. These parts are complete product of custom designed. The material can be the manganese steel or ...
Metal recycling shredder wear parts Mayang Castings shredder wear parts run tough and wear long. Cast in our ISO 9001 foundry, all our wear parts, from hammers and grates to pin protectors and caps, are made from virgin materials with exacting attention to detail and our proprietary heat treat cycle.
Shredder Hammers | Wear Parts For Industry | Qiming Casting. We have engineered a metal alloy that is optimized for metal shredding. Combined with rigorous lean manufacturing processes at our foundries, Qiming Casting has brought to the market a shredder hammer line that provides the lowest cost-per-ton for our customers.
Scrap shredder wearing parts. Sinco also manufacture wear-resistant castings parts for metal shredder and scrap metal recycling machine, these parts including grate bar, reject door, pin protect, shredder anvils and cap. These parts are complete product ...
MRS-2 Metal Recycling Plant. This metal recycling plant is designed to recycle and shred scrap metal in around 10 Tons per hour, to process and separate the ferrous metal and non-ferrous metal from other waste for smelters. Adopt Metal shredder and Hammer shredder for metal scraps recycling processing.
Metal Shredder Hammer Crusher Wear Parts Used to Concrete Metal Recycling Equipment Jaw plate is the main wear part of jaw crusher, it has two types: swing and fixed types. Based on different demands, the material can be Mn13, Mn18, Mn13Cr2, Mn18Cr2, etc.
30CrNiMo Low Alloy Steel Shredder Hammer. 30CrNiMo Low Alloy Steel hammers provide longer life and often better value for operations that dont run a steady diet of autos and heavier scrap that work hardens manganese hammers.Our 30CrNiMo Low Alloy Steel hammers offer hardness at the working end and less hardness around the hammers pin hole.
Alibaba.com offers 1,763 alloy steel shredder hammer products. About 33% of these are Mining Machinery Parts, 0% are Wood Crusher, and 9% are Crusher. A wide variety of alloy steel shredder hammer options are available to you, such as condition, local service location, and material.
Nonferrous metals are particularly valuable as they can recover a substantial amount of the price paid by the recycler for the ship. While there are many kinds of nonferrous scrap, one of particular interest is copper-yielding scrap, i.e., cuprous scrap. Cuprous scrap can be classified into bronze, brass, and various other copper alloys. Copper is a high value commodity for which recycling markets exist for reclaiming scrap copper.
One of the major sources of copper in a ship is electrical cabling (Fig. 11). According to certain estimates (Mishra and Mukherjee, 2009), on an average sized ship there are about 50,000 m of cables containing about 40,000 kg of copper. Such cable is recycled by stripping off the insulated covering and other layers to recover the copper. The resulting copper can be sold as scrap and the insulation material would add to the relevant waste stream. Alternatively the cable can be sold to an intermediary for such separation.
Another main source of copper is transformers and electric motor windings. Copper may also arrive from the waste stream of electrical and electronic equipment. Copper pipework can be sold directly unless highly contaminated. Special bronze alloys used in the manufacturing of propellers are equally valuable and are sought after in the recycling market.
Other nonferrous metals recovered from scrapping a ship include aluminum and zinc. Anodes, mainly of aluminum and zinc, are fitted to both the vessels hull and inside tanks in order to protect against corrosion and fouling. Anodes are sacrificed over the lifetime of the ship and the amount of metals left when the ship arrives for scrapping are removed and sorted for reuse/resale (Andersen et al., 2001). The quantities remaining are likely to vary between 30 and 70% of the initial weight, depending on the time spent on the high seas (Mishra and Mukherjee, 2009). Heavily corroded anodes are disposed of as waste, if recycling is not a feasible option.
The main use of MA of nonferrous metals has been in the present-day development of commercial oxide dispersion-strengthened (ODS) nickel-, copper-, and aluminum-base alloys. The feature of these materials is elevated temperature strength, which is derived from several mechanisms. First, their structure is characterized by uniform dispersion with a spacing of about 100nm by very fine (from 5 to 50nm) oxide particles of stable oxides such as alumina (Al2O3), titania (TiO2), thoria (ThO2), yttria (Y2O3), lanthana (La2O3), and beryllia (BeO). This dispersion inhibits dislocation motion in the metal matrix and increases the resistance of the alloy to creep deformation. Another function of the dispersoid particles is to inhibit the recovery and recrystallization processes. Second, the homogeneous distribution of alloying elements due to MA gives both the solid-solution strengthened and precipitation-hardened alloys more stability at elevated temperatures and improvement in properties. Mechanically alloyed materials also have high oxidation and hot corrosion resistance.
The production of ODS alloys on a commercial scale uses as raw materials elemental powders, crushed master alloy (intermetallic) powders, and prealloyed powders. Yttria powder as well as other oxide powders with narrow ranges of crystallite size (preferably when the crystallite size is below 30nm) and metal powders are mixed together to form a bulk feedstock. These mixtures are charged into large tumbling ball mills or attritors with steel balls. During milling, an equilibrium powder particle size distribution is established until each individual particle achieves the alloying constituents in the given proportions. The mechanically alloyed powder from the mill is then filled into stainless steel containers. Then the powder is consolidated at elevated temperatures, usually by either extrusion or hot isostatic pressing (HIP). In most cases, extrusion is preferred because it is less expensive then HIP. The former is accomplished in the following way. The powder is loaded into mild steel extrusion cans with characteristic sizes up to 300mm in diameter and 900mm in length and containing up to 280kg. The batch is held for several hours in a furnace at the extrusion temperature, during which time homogenization of the powder and complete alloying occur if that has not already been accomplished during milling. Extrusion is done in commercial presses at temperatures, ratios, and speeds that are independent variables, depending on the properties of the material.
Markets served by specialty refractories include the production of ferrous and nonferrous metals and glasses as well as the processing of chemicals and ceramics. Products used in these markets range from kiln furniture, crucibles, and nozzles to pouring shrouds, tundishes, and wear-resistant parts. Refractory and ceramic components containing cordierite as a major constituent are generally used where low thermal expansion and good thermal shock resistance are required. Ceramic grade zirconia is used in a wide variety of applications. Refractoriness, thermal-shock resistance, and resistance to molten-metal erosion make zirconia ceramic a useful material for tundish nozzles and other specialty parts in the casting of molten steel and for foundry crucibles. Zirconia ceramics have found unique application in areas other than in high-temperature environments. The axial thermal expansion of eucryptite is highly anisostropic, with positive expansion in the a crystallographic direction and negative expansion in the c direction. Useful ceramic products can be developed from eucryptite and eucryptitesilica solid-solution compositions by controlling stresses and stress-relief mechanisms caused by the anisotropic thermal expansion.
An eddy current separator (ESC) is used to remove nonferrous metals such as aluminum, brass, and copper from the waste stream. The material is separated in an ECS on the basis of eddy currents being generated in nonferrous materials by rapidly rotating permanent magnets. These eddy currents in turn cause the material to be repulsed by the magnet field of the ECS, and the nonferrous material is diverted from the waste stream and is ejected into a separate hopper or conveyor. Trials have demonstrated that ECS is effective at separating a significant proportion of multilayer packaging from the waste stream, alongside other nonferrous materials such as aluminum used beverage cans (UBCs) and aluminum foil . ECS has been used in combination with other separating devices such as ballistic or angled disc screen separator and optical systems for the separation of plastic films and/or paper from other recyclables (2017, US9713812 B1; US2017253891 A1, ORGANIC ENERGY CORP). It has been proposed to use ECS as an additional separating device in the processing line of an MRF for the separation of pouches from the waste stream .
The Fe4.7Co65.6Ni3.4Cr1.1Nb2.2B13.8 Si9.1 metallic glass ribbons were prepared by planar flow casting at Non-Ferrous Metal Factory of Csepel Works using a 260 mm diameter (copper)roller with substrate velocity 16 m/s and ejection pressure 20 kPa. The samples were produced with varying sticking times (ts): 7, 13, 23, 39 ms. The magnetostriction coefficient of the amorphous alloy12 is = 1.7 107.
The Q1 and G/G25 measurements were made on 11.5 mm wide and 40 mm long specimens cut from the central part of the 12 mm wide and 40 m thick ribbons. A K pendulum with 5 MPa stress and = 104 relative deformation was used13 between 25 and 650C at heating rate 4 K/min. The measurements of HV were made with the same load (F = ln) and loading rate at RT. In all cases the depth of mark was less than 20% of the total thickness. Every time 10 measurements were carried out in each state and the scattering of data was within 2%.
An Eddy current separator (ECS) uses a powerful magnetic field to separate nonferrous metals from waste after all ferrous metals have been removed previously by some arrangement of magnets. The device makes use of eddy currents to effect separation. ECSs are not designed to sort ferrous materials, which become hot inside the eddy current field. This can lead to damage of ECS unit belt. ECS is applied to a conveyor belt carrying a thin layer of e-waste. Nonferrous metals are thrown forward from the belt into a product bin, while nonmetals simply fall off the belt due to gravity. ECSs use a rotating drum with permanent/electro magnet. Fig. 12 shows the separation principles of ECS and pilot-scale equipment. It is mainly used for recycling Cu, Al and other nonferrous metals from industrial waste and living garbage waste, can be widely used in garbage disposal, recycling of WEEE, other environmental industry and nonferrous metal materials processing industry. The main criterion to distinguish is the ratio of material conductivity and density values, the higher ratio value is more likely to separate. Typical particulate sizes processed tend to be in the 3150 mm size range. High frequency ECSs, where the magnetic field changes very rapidly, are needed for separation of smaller particles (Kellner, 2009).
ECSs produce high frequency alternating magnetic field on magnetic roller; if conductive nonferrous metal goes through the magnetic field, it will produce induced current and this induced current will produce magnetic field opposite with original magnetic field, then the nonferrous (i.e., Al, Cu etc.) metal will fly ahead according its transporting direction by repulsive force of the magnetic field; hence, nonferrous metal is separated from other non-metal material. ECSs are composed of a separator and an electric controlling cabinet. Main body includes separating assembly, motor, frame and cover etc. Separating assembly includes permanent magnet roller (FeBNd), transporting system (includes transporting belt, driving roller and reducer). ECSs have a good separating result for multiple nonferrous metals, strong adaptability, reliable structure, strong adjustable repulsion with high separating efficiency. Magnet roller diameter is generally 300 mm. Magnet roller revolution changes up to 3000 rpm. Belt width ranges from 450 to 1250 mm and speed up to 1.0 m s1. Handling capacity changes from 2 to 2.6 t (Web 6). Turn key 200300 kg h1, 300500 kg h1 and 10001500 kg h1 WPCB recycling lines with electrostatic separation are available on the market today. Power requirement changes from 43 kW to 172 kW and area requirement from 80 to 200 m2. Lowest capacity plants have one shredder, classifier, cyclone, dust catcher, vibrating screen and electrostatic separator along with two bucket elevators. Highest capacity plants have one double-shaft shredder, hammer mill, bucket elevator and storage bin; two belt conveyor, specialized crusher, classifier, cyclone, four level cyclone, three-in-one dust catcher, vibrating screen; four electrostatic separator and six bucket elevators. Fig. 13 shows industrial scale integrated physico-mechanical WPCB recycling plant flowsheet with air separator and ECSs along with feed-product photos obtained.
Fig. 13. Physico-mechanical e-waste recycling plant: (a) integrated desoldering disassembly, shredder, pulverizers, air separator and ECS plant layout, and (b) flowsheet for metal (Cu)-nonmetal (resin/glass fiber) products.
Non-ferrous slags are manufactured during mate and smelting process used for extraction of nonferrous metals from ores, including for example copper, nickel, phosphorus, lead, lead-zinc or zinc. The copper slag usually contains Fe2O3, SiO2, Al2O3 and CaO. On the average, one ton of the copper slag is produced from each three tons of the extracted copper. Yearly production of copper reaches 20 mln tones, which roughly corresponds to 6.5 mln tons of the copper slag. Typically, the copper slag is used as aggregates for road construction (Shi et al., 2008) and to a smaller extend in the production of a normal concrete. Recently, results showed that it could be also used in SCC concrete (Fig. 10.1).
TIG torch is most frequently used to weld thin sections of stainless steels and nonferrous metals for instances aluminium, magnesium, nickel and copper (Panigrahi and Sarangi, 2017). Recently, several research works have been conducted on TIG torch surface melting that produces positive results in terms of surface morphology, wear and hardness behavior. (Adeleke and Maleque, 2015; An et al., 2017; Ardeshiri et al., 2017; Ghaffari et al., 2016; Lailatul and Maleque, 2017; Mridha and Baker, 2015a; Muoz et al., 2017; Stadler et al., 2017).
Alloy steels are the most common reported materials used in TIG torch surface melting technology. Muoz et al. (2017) successfully developed metal matrix composite layer on a microalloyed steel surface by dissociating MAX211 Ti2AlC particles using a TIG torch technique. Other work using TIG torch surfacing was done by Mridha and Baker (2015a) on low alloy steel surface using titanium carbide (TiC) as reinforcement powder. Stadler et al. (2017) study the influence of welding parameters on the weld pool dimensions and shape in a TIG configuration using AISI 304L stainless steel. Bello et al. (2016) successfully developed TIG-alloyed hybrid composite coating on AISI 4340 low alloy steel substrate. Lailatul and Maleque (2017) have modified the surface of duplex stainless steel with SiC preplacement using TIG torch cladding.
Mridha and Baker (2015b) also utilized the TIG torch surfacing to examine the corrosion resistance of titanium aluminide coating on pure titanium substrate. The hardness of the surface alloyed layer was found at 400600 HV0.5kgf which is higher than the substrate hardness (180 HV0.5kgf). The surface alloyed layers also exhibited six times higher oxidation resistance compared to the titanium substrate. Adeleke and Maleque (2015) study the deposition of powder blends of Fe, Si and C on pure titanium Grade 2 by TIG torch surfacing technique to enhance its wear resistance properties. An et al. (2017) have performed the TIG torch surfacing on titanium alloy Grade 5 using TiB reinforcement to study the microstructure developed and mechanical performance of the new modified surface. The maximum hardness obtained for the new developed TiB2/Ti-6Al-4V composite was 800 HV0.2kgf which is 128% higher than the Ti-Al-4V alloy substrate. The coefficient of friction for the new surface of TiB2/Ti-6Al-4V composite is 0.36 which is also considerably lower than the substrate (0.48). It can be concluded that the TIG torch surface melting is a potential low cost method to improve the surface properties of Ti-6Al-4V alloy.
Surface alloying of A2618 aluminium alloy by Ardeshiri et al. (2017) was carried out by pre-placing powder blend of silicon and iron and subsequent TIG process. Surface alloying of AZ31 magnesium alloy was also performed using TIG torch surfacing by Ghaffari et al. (2016). The coating reinforcement materials used are the same as previous authors i.e., a mixture of silicon and iron.
Overall, TIG torch surfacing technique can be utilized on almost all metals except zinc and its alloys. This is due to very little difference between the melting and boiling point of zinc and thus could vaporized during TIG welding process. The fumes released are also toxic and hazardous to health (Weman, 2003). However, the surfacing technique is suitable to be used on a wide range of metallic materials including various grades of alloy steels, nonferrous materials such as titanium, aluminium and magnesium and their respective alloys or composite.
In the automotive production, rubbers, fibers, plastics, steel, ferrous and nonferrous metals are assembled to produce a vehicle (Nourreddine, 2007; Morselli et al., 2010). Each material in percentages constituting the end-of-life vehicles (ELV) is shown in Table 10.1 (Vermeulen et al., 2011; Cossu and Lai, 2015). Plastic amounts to 12% of auto vehicles that are currently produced. The utilization of plastics in the manufacturing of motor vehicles is expected to increase due to their availability at a lower cost and lightweight property (Evangelopoulos et al., 2018).
Source: Vermeulen, I., Van Caneghem, J., Block, C., Baeyens, J., Vandecasteele, C., 2011. Automotive shredder residue (ASR): reviewing its production from end-of-life vehicles (ELVs) and its recycling, energy or chemicals valorisation. J. Hazard. Mater. 190(13), 827.
Production of motor vehicles has increased in the past 20years to 58 million units with commercial vehicles excluded. Motor vehicles are predominantly produced in Japan, North America, and Western Europe. Zorpas and Inglezakis (2012) have mentioned that the largest producer is Europe which manufactures almost 30% of the global 50 million vehicles. The production decreased in the year 2008 by 3.7% and by 12.8% in 2009 due to an unstable economy, although, it is expected to increase by 32% in 2020. After cars have reached their ELV stage, they are shredded into waste, also called as car fluffs. Cars reach their ELV because they are damaged, deregistered, and abandoned. However, certification of destruction is required in the recycling plant so that ELVs are lawfully disposed of. Motor vehicles were firstly shredded in the year 1958 (Nourreddine, 2007; Mancini et al., 2010; Vermeulen et al., 2011). In European countries, motor vehicles that reached their end of life (EOL) in the year 1996 were 8 million and it was expected that it will be 11 million in 2015 (Nourreddine, 2007; Vermeulen et al., 2011). The increase in the number of vehicles reaching their EOL is influenced by scrappage schemes introduced by the states department (Cossu and Lai, 2015). Vigano and his coauthors reported that 12.8 million of passenger vehicles are deregistered annually. It is not clear whether the deregistered vehicles will be fixed to meet the requirements set by the department of transport or they reached their EOL (Vigano et al., 2010). Notwithstanding, almost 75% of these vehicles are either recycled or reused, with 25% of auto fluffs end up in landfill or incinerated due to their complexity and not easy to process (recycle), therefore, result in automotive waste. Statistics have shown that waste caused by vehicles is above 9 million t annually in Europe alone. Auto fluffs are also disposed of in landfills due to the existence of a hazardous substance in vehicle fluffs, shortage of ELV recyclers, and avoiding recycling cost. Vermeulen et al. (2011) have reported that auto fluffs are grouped under hazardous waste. Hazardous is influenced by the existence of perilous substances and leachate collected from the waste.
Perilous substances include polychlorinated biphenyl (PCB) and polyvinyl chloride/chlorine (PVC/Cl). Cl produces hydrochloric acid while decomposing and it can corrode and decrease the service life of equipment utilized in the recycling process. Chemical corrosion of equipment can be minimized by dechlorinating automobile shredder residue (ASR) using either calcium hydroxide or calcium carbonate before performing processes such as thermal treatment and incineration.
Vehicle fluffs end up in landfills besides containing copper wires, zinc, and plastics which can add value to the economy if utilized efficiently. Smaller fragments of copper wire are found either intertwined or connected to other materials and they account for 15kg of ELV in total. In addition, smaller pieces of textiles, rocks, dust, ceramic, and coating paint are found in vehicle fluffs (Berzi et al., 2013; Cossu et al., 2014; Cossu and Lai, 2015). Joung and his coauthors have highlighted that car fluff is composed of 25% of textiles, 17% of sponge, and 16% of sand (Joung et al., 2007). Processing plants around the world received almost 4000t each year of ASR to be incinerated.
Dumping waste into landfills results in environmental pollution and influences climate change. It is not only car fluffs impacting the environment, energy, and resource consumption, emissions gases such as carbon dioxide (CO2) and nitrogen oxide (NOx) are of concern in the vehicles life cycle. Therefore, the environmental impact needs to be addressed in all life cycle stages. The drawback of CO2 emissions is that it is nonrenewable (Robson and Goodhead, 2003; Vigano et al., 2010). Due to the increase in car fluffs discarded in the landfill, strict landfill waste laws have been introduced as well as surcharging anyone including companies disposing of ASR in landfills (Soo et al., 2017).
The region of Kosovo and Metohija is rich in mineral resources. Its energy resources and non-ferrous metal resources represent a considerable potential for the overall development. Not all parts of Kosovo and Metohija are equally rich in mineral raw materials. Mineral deposits represent a true natural basis for development of industry, i.e., economy as a whole. Some of the most important resources are lignite, minerals of lead, zinc, silver and gold, silicate minerals of nickel and cobalt, iron bauxite, manganese and magnesite. Moreover, there are also significant amounts of non-metallic, industrial minerals and geological construction materials. Specified mineral resources and their rational exploitation combined with good management approach represent a solid basis for quick and sustainable economic and social development.
All kinds of existing resources that a country has at its disposal make up a foundation for planning and implementation of development and energy strategy. Each of the specified resources has bigger or smaller resource potential, but planning and strategic exploitation are insufficient. That is why it is necessary to define accurate sector policies and strategies and to select proper mechanisms for their implementation. Regarding Serbia, this goal is extremely difficult to realize at this moment because the region of Autonomous Province of Kosovo and Metohija is a UN protectorate and subject to a Resolution 1244. In fact, at this moment Serbia as a country does not have any mechanisms that could be used to protect those natural mineral resources from exploitation. On the other hand interim institutions in Kosovo and Metohija are doing everything in their power to use those resources for their own development. Pursuant to any natural and international law, including resolution 1244, mineral resources of Kosovo and Metohija should stay in Serbia. Since Serbia has been exposed to double standards by the developed Western countries that recognized unilateral independence of AP of Kosovo and Metohija, the so called independent state of Kosovo was given the opportunity to exploit all of the mineral resources (Figs. 13).
Fig. 1. Mineral resources in Kosovo and Metohija. Reproduced from http://www.nspm.rs/kosovo-i-metohija/u-cijim-rukama-ce-se-naci-prirodna-bogatstva-kosova-i-metohije.html?alphabet=l (accessed 15.01.18).
Fig. 2. Mining fields of lignite Sibovac. Reproduced from Kosovo Power Project, Environmental and Social Impact Assessment (ESIA), Draft Environmental and Social Scoping Study (ESSS) Rev. 2. pp. 2125.
This crusher developed by Jaques (now Terex Mineral Processing Solutions) has several internal chamber configurations available depending on the abrasiveness of the ore. Examples include the Rock on Rock, Rock on Anvil and Shoe and Anvil configurations (Figure 6.26). These units typically operate with 5 to 6 steel impellers or hammers, with a ring of thin anvils. Rock is hit or accelerated to impact on the anvils, after which the broken fragments freefall into the discharge chute and onto a product conveyor belt. This impact size reduction process was modeled by Kojovic (1996) and Djordjevic et al. (2003) using rotor dimensions and speed, and rock breakage characteristics measured in the laboratory. The model was also extended to the Barmac crushers (Napier-Munn et al., 1996).
Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.
A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.
A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.
Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.
Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.
The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.
A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit . The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.
Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.
A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.
A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.
Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.
The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit . The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.
Secondary coal crusher: Used when the coal coming from the supplier is large enough to be handled by a single crusher. The primary crusher converts the feed size to one that is acceptable to the secondary crusher.
The main sources of RA are either from construction and ready mixed concrete sites, demolition sites or from roads. The demolition sites produce a heterogeneous material, whereas ready mixed concrete or prefabricated concrete plants produce a more homogeneous material. RAs are mainly produced in fixed crushing plant around big cities where CDWs are available. However, for roads and to reduce transportation cost, mobile crushing installations are used.
The materiel for RA manufacturing does not differ from that of producing NA in quarries. However, it should be more robust to resist wear, and it handles large blocks of up to 1m. The main difference is that RAs need the elimination of contaminants such as wood, joint sealants, plastics, and steel which should be removed with blast of air for light materials and electro-magnets for steel. The materials are first separated from other undesired materials then treated by washing and air to take out contamination. The quality and grading of aggregates depend on the choice of the crusher type.
Jaw crusher: The material is crushed between a fixed jaw and a mobile jaw. The feed is subjected to repeated pressure as it passes downwards and is progressively reduced in size until it is small enough to pass out of the crushing chamber. This crusher produces less fines but the aggregates have a more elongated form.
Hammer (impact) crusher: The feed is fragmented by kinetic energy introduced by a rotating mass (the rotor) which projects the material against a fixed surface causing it to shatter causing further particle size reduction. This crusher produces more rounded shape.
Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.
Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.
Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.
The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.
Roll crushers are arbitrarily divided into light and heavy duty crushers. The diameters of the light duty crushers vary between 228 and 760mm with face lengths between 250 and 460mm. The spring pressure for light duty rolls varies between 1.1 and 5.6kg/m. The heavy duty crusher diameters range between 900 and 1000mm with face length between 300 and 610mm. In general, the spring pressures of the heavy duty rolls range between 7 and 60kg/m. The light duty rolls are designed to operate at faster speeds compared to heavy duty rolls that are designed to operate at lower speeds.
It has been stressed that the coal supplier should initially crush the materials to a maximum size such as 300 mm, but they may be something else depending on the agreement or coal tie up. To circumvent the situation, the CHP keeps a crushing provision so that coal bunkers receive the materials at a maximum size of about 2025 mm.
The unloaded coal in the hoppers is transferred to the crusher house through belt conveyors with different stopovers in between such as the penthouse, transfer points, etc., depending on the CHP layout.
Suspended magnets for the removal of tramp iron pieces and metal detectors for identifying nonferrous materials are provided at strategic points to intercept unacceptable materials before they reach the crushers. There may be arrangements for manual stone picking from the conveyors, as suitable. Crushed coal is then sent directly to the stockyard.
A coal-sampling unit is provided for uncrushed coal. Online coal analyzers are also available, but they are a costly item. Screens (vibrating grizzly or rollers) are provided at the upstream of the crushers to sort out the smaller sizes as stipulated, and larger pieces are guided to the crushers.
Appropriate types of isolation gates, for example, rod or rack and pinion gates, are provided before screens to isolate one set of crushers/screens to carry on maintenance work without affecting the operation of other streams.
Vibrating grizzly or roller screens are provided upstream of the crushers for less than 25 (typical) mm coal particles bypass the crusher and coal size more than 25 mm then fed to the crushers. The crushed coal is either fed to the coal bunkers of the boilers or discharged to the coal stockyard through conveyors and transfer points, if any.
This is used for crushing and breaking large coal in the first step of coal crushing plant applied most widely in coal crushing industry. Jaw crushers are designed for primary crushing of hard rocks without rubbing and with minimum dust. Jaw crushers may be utilized for materials such as coal, granite, basalt, river gravel, bauxite, marble, slag, hard rock, limestone, iron ore, magazine ore, etc., within a pressure resistance strength of 200 MPa. Jaw crushers are characterized for different features such as a simple structure, easy maintenance, low cost, high crushing ratio, and high resistance to friction/abrasion/compression with a longer operating lifespan.
Fixed and movable jaw plates are the two main components. A motor-driven eccentric shaft through suitable hardware makes the movable jaw plate travel in a regulated track and hit the materials in the crushing chamber comprising a fixed-jaw plate to assert compression force for crushing.
A coal hammer crusher is developed for materials having pressure-resistance strength over 100 Mpa and humidity not more than 15%. A hammer crusher is suitable for mid-hard and light erosive materials such as coal, salt, chalk, gypsum, limestone, etc.
Hammer mills are primarily steel drums that contain a vertical or horizontal cross-shaped rotor mounted with pivoting hammers that can freely swing on either end of the cross. While the material is fed into the feed hopper, the rotor placed inside the drum is spun at a high speed. Thereafter, the hammers on the ends of the rotating cross thrust the material, thereby shredding and expelling it through the screens fitted in the drum.
Ring granulators are used for crushing coal to a size acceptable to the mills for conversion to powdered coal. A ring granulator prevents both the oversizing and undersizing of coal, helping the quality of the finished product and improving the workability. Due to its strong construction, a ring granulator is capable of crushing coal, limestone, lignite, or gypsum as well as other medium-to-hard friable items. Ring granulators are rugged, dependable, and specially designed for continuous high capacity crushing of materials. Ring granulators are available with operating capacities from 40 to 1800 tons/h or even more with a feed size up to 500 mm. Adjustment of clearance between the cage and the path of the rings takes care of the product gradation as well as compensates for wear and tear of the machine parts for maintaining product size. The unique combination of impact and rolling compression makes the crushing action yield a higher output with a lower noise level and power consumption. Here, the product is almost of uniform granular size with n adjustable range of less than 2025 mm. As the crushing action involves minimum attrition, thereby minimum fines are produced with improving efficiency.
A ring granulator works on n operating principle similar to a hammer mill, but the hammers are replaced with rolling rings. The ring granulator compresses material by impact in association with shear and compression force. It comprises a screen plate/cage bar steel box with an opening in the top cover for feeding. The power-driven horizontal main shaft passes from frame side to frame side, supporting a number of circular discs fixed at regular intervals across its length within the frame. There are quite a few bars running parallel to the main shaft and around the periphery that pass through these discs near their outer edges. The bars are uniformly located about the center of the main rotating shaft. There are a series of rings in between the two consecutive disc spaces, mounted on each bar. They are free to rotate on the bars irrespective of the main shaft rotation. The entire cage assembly, located below the rotor assembly, can be set at a desired close proximity to the rings by screw jack mechanism adjustable from outside the crusher frame. The rotor assembly consisting of the shaft, discs, rings, etc., is fixed as far as the main shaft center line is concerned. This main shaft carries in roller bearings from the box sides. The movable cage frame arrangement is provided so as to set its inner radius marginally larger than that of the ring running periphery. When coal is fed from the top, the rings also rotate along with the shaft and around their own center line along the bars, which drags coal lumps and crushes them to the desired size. After the coal has been crushed by the coal crusher, a vibrating screen grades the coal by size and the coal is then transported via belt conveyor. In this process, a dewatering screen is optional to remove water from the product.
Crusher machines are used for crushing of a wide variety of materials in the mining, iron and steel, and quarry industries. In quarry industry, they are used for crushing of rocks into granites for road-building and civil works. Crusher machines are equipped with a pair of crusher jaws namely; fixed jaws and swing jaws. Both jaws are fixed in a vertical position at the front end of a hollow rectangular frame of crushing machine as shown in Fig.10.1. The swing jaw is moved against the fixed jaws through knuckle action by the rising and falling of a second lever (pitman) carried by eccentric shaft. The vertical movement is then horizontally fixed to the jaw by double toggle plates. Because the jaw is pivoted at the top, the throw is greatest at the discharge, preventing chocking.
The crushing force is produced by an eccentric shaft. Then it is transferred to the crushing zone via a toggle plate system and supported by the back wall of the housing of the machine. Spring-pulling rods keep the whole system in a condition of no positive connection. Centrifugal masses on the eccentric shaft serve as compensation for heavy loads. A flywheel is provided in the form of a pulley. Due to the favorable angle of dip between the crushing jaws, the feeding material can be reduced directly after entering the machine. The final grain size distribution is influenced by both the adjustable crusher setting and the suitability of the tooth form selected for the crushing plates.
Thus, the crusher jaws must be hard and tough enough to crush rock and meet the impact action generated by the action of swing jaws respectively. If the jaws are hard, it will be efficient in crushing rock but it will be susceptible to fracture failure. On the other hand, if the jaws are tough, the teeth will worn out very fast, but it will be able to withstand fracture failure. Thus, crusher jaws are made of highly wear-resistant austenitic manganese steel casting, which combines both high toughness and good resistance to wear.
Austenitic manganese steel was invented by Sir Robert Hadfield in 1882 and was first granted patented in Britain in 1883 with patent number 200. The first United States patents, numbers 303150 and 303151, were granted in 1884. In accordance with ASTM A128 specification, the basic chemical composition of Hadfield steel is 1%1.4% carbon and 11%14% manganese. However, the manganese to carbon ratio is optimum at 10:1 to ensure an austenitic microstructure after quenching . Austenitic manganese steels possess unique resistance to impact and abrasion wears. They exhibit high levels of ductility and toughness, slow crack propagation rates, and a high rate of work-hardening resulting in superior wear resistance in comparison with other potentially competitive materials . These unique properties have made Hadfield's austenitic manganese steel an engineering material of choice for use in heavy industries, such as earth moving, mining, quarrying, oil and gas drilling, and in processing of various materials for components of crushers, mills, and construction machinery (lining plates, hammers, jaws, cones).
Austenitic manganese steel has a yield strength between 50,000psi (345MPa) and 60,000psi (414MPa) . Although stronger than low carbon steel, it is not as strong as medium carbon steel. It is, however, much tougher than medium carbon steel. Yielding in austenitic manganese steel signifies the onset of work-hardening and accompanying plastic deformation. The modulus of elasticity for austenitic manganese steel is 27106psi (186103MPa) and is somewhat below that of carbon steel, which is generally taken as 29106psi (200103MPa). The ultimate tensile strength of austenitic manganese steel varies but is generally taken as 140,000psi (965MPa). At this tensile strength, austenitic manganese steel displays elongation in the 35%40% range. The fatigue limit for manganese steel is about 39,000psi (269MPa). The ability of austenitic manganese to work-harden up to its ultimate tensile strength is its main feature. In this regard austenitic manganese has no equal. The range of work-hardening of austenitic manganese from yield to ultimate tensile is approximately 200%.
When subjected to impact loads Hadfield steel work-hardens considerably while exhibiting superior toughness. However, due to its low yield strength, large deformation may occur and lead to failure before the work-hardening sets in . This phenomenon is detrimental when it comes to some applications, such as rock crushing . Work-hardening behavior of Hadfield steel has been attributed to dynamic strain aging . The hardening or strengthening mechanism has its origin in the interactions between dislocations and the high concentration of interstitial atoms also known as the CottrellBilby interaction. Thus, the wear properties of Hadfield steel are related to its microstructure, which in turn is dependent on the heat-treatment process and chemical composition of the alloy. According to Haakonsen , work-hardening is influenced by such parameters as alloy chemistry, temperature, and strain rate.
Carbon content affects the yield strength of AMS. Carbon levels below 1% cause yield strengths to decrease. The optimum carbon content has been found to be between 1% and 1.2%. Above 1.2% carbides precipitate and segregate to grain boundaries, resulting in compromised strength and ductility particularly in heavy sections . Other alloying elements, such as chromium, will increase the yield strength, but decrease ductility. Silicon is generally added as a deoxidizer. Carbon contents above 1.4% are not generally used as the carbon segregates to the grain boundaries as carbides and is detrimental to both strength and ductility .
Manganese has very little effect on the yield strength of austenitic manganese steel, but does affect both the ultimate tensile strength and ductility. Maximum tensile strengths are attained with 12%13% manganese contents . Although acceptable mechanical properties can be achieved up to 20% manganese content, there is no economic advantage in using manganese contents greater than 13%. Manganese acts as an austenitic stabilizer and delays isothermal transformation. For example, carbon steel containing 1% manganese begins isothermal transformation about 15s after quenching to 371C, whereas steel containing 12% manganese begins isothermal transformation about 48h after quenching to 371C .
Austenitic manganese steel in as-cast condition is characterized by an austenitic microstructure with precipitates of alloyed cementite and the triple phosphorus eutectic of an Fe-(Fe,Mn)3C-(Fe,Mn)3P type , which appears when the phosphorus content exceeds 0.04% . It also contains nonmetallic inclusions, such as oxides, sulfides, and nitrides. This type of microstructure is unfavorable due to the presence of the (Fe, Mn)xCy carbides spread along the grain boundaries . However, in solution-treated conditions austenitic manganese steel structure is essentially austenitic because carbon is in austenite solution . The practical limit of carbon in solution is about 1.2%. Thereafter, excess carbon precipitation to the grain boundaries results, especially in heavier sections .
Austenitic manganese steel in the as-cast condition is too brittle for normal use. As section thickness increases, the cooling rate within the molds decreases. This decreased cooling rate results in increased embrittlement due to carbon precipitation. In as-cast castings, the tensile strength ranges from approximately 50,000psi. (345MPa) to 70,000psi (483MPa) and displays elongation values below 1%. Heat treatment is used to strengthen and increase the mechanical properties of austenitic manganese steel. The normal heat-treatment method consists of solution annealing and rapid quenching in a water bath.
Considering the mechanical properties, it is difficult to imagine that a casting made from Hadfield steel could suffer failure in service. However, cases like this do happen, especially in heavy-section elements and result in enormous losses of material and long downtimes. The reason for such failures is usually attributed to insufficient ductility, resulting from sensitivity of austenitic manganese steel to section size, heat treatment, and the rapidity and effectiveness of quenching . Poor quench compounded by large section size results in an unstable, in-homogenous structure, subject to transformation to martensite under increased loading and strain rate. This article investigates the cause of incessant failure of locally produced crusher jaws from Hadfield steel.
According to the recent marketing research data conducted by the foundry an estimate of 15,000metrictons of this component is being consumed annually in the local market. This is valued at about $30million. From this market demand, the foundry plant can only supply about 5% valued at $1.5million. This is because the crusher jaws produced locally failed prematurely. Hence, this study aimed at investigating the causes of failure.
Annual wine exports in the European Union is around 21.9 billion (Eurostat) with France being the main wine exporting country followed by Italy and Spain. The wine production process (Fig. 9.1) can be divided into the following stages (Sections 184.108.40.206.2.1.4).
Grape crushers or crusher destemmers are initially used via light processing to avoid seed fracture. Sulfur dioxide is added to the mass to prevent oxidation. At this stage, grape stems are produced as one of the waste streams of the winery process. The mash is pressed in continuous, pneumatic, or vertical basket presses leading to the separation of the pomace (marc) from the must. Microbial growth is suppressed via sulfur dioxide addition.
The solids present in the must are removed before or after fermentation for white wine production. Fining is achieved by combined processes including filtration, centrifugation, flocculation, physicochemical treatment (e.g., activated carbon, gelatin, etc.,), and stabilization to prevent turbidity formation (e.g., the use of bentonite, cold stabilization techniques, etc.). Clarification leads to the separation of sediments via racking.
Wine production is carried out at temperatures lower than 20C for 610 weeks in stainless steel bioreactors or vats with or without yeast inoculation (most frequently Saccharomyces cerevisiae). At the end of fermentation, the wine is cooled (4C5C) and subsequently aged in barrels or wooden vats. The sediment that is produced during fermentation and aging is called wine lees and constitutes one of the waste streams produced by wineries. Current uses of wine lees include tartrate production and ethanol distillation. Lees could also be processed via rotary vacuum filtration for recycling of the liquid fraction and composting of the solid fraction.
Wine is cooled rapidly to facilitate the precipitation of tartrate crystals. Fining is applied for the separation of suspended particles using bentonite and gelatin. Filtration is subsequently applied to remove any insoluble compounds. The wine is finally transferred into bottles.
The main differences in the red wine production process are skin maceration duration, fermentation temperature, and unit operation sequence. Whole crushed grapes are most frequently used in red wine fermentation, which is carried out at 22C28C to facilitate the extraction of color and flavors. The remaining skins, seeds, and grape solids after fermentation are pressed to recover wine with the correct proportions of tannins and other compounds necessary for the final wine product.
Casting offers exceptional freedom in forming intricate components. It is also conducive to high-volume production runs, where material quantities can be efficiently controlled to minimize waste and reduce cost. The casting process is also calledfounding.
Casting method in which a reusable mold is rotated at high speed to force molten metal against the inside walls. Centrifugal casting allows castings to be formed at almost any length or wall thickness without the use of a core. Finished products are free from parting lines, gates and risers. Centrifugal casting is often used to make stock pipes and tubes for further machining.
Casting method in which molten metal is injected into the mold (or die) under pressure. Two hardened dies are pressed together to form the mold cavity. Once the injected metal has cooled, dies are separated and the casting ejected. Die casting can achieve high dimensional accuracy, intricate detail and smooth cast surfaces that require minimal additional machining. Dies are expensive to produce, making them more suitable for high-volume runs. Ferrous metals are rarely used as an injection material.
Casting method typically used for intricate pieces that require a high degree of accuracy with minimal machining. It can be used to create products with smooth surfaces and no parting lines. Due to high setup costs, investment casting is most suitable for high-volume production.
Casting method characterized by the use of sand as the mold material. Molding sand is typically mixed with a bonding agent such as clay and moistened with water or other liquid to create suitable mold strength and plasticity (Seegreen sand). The mold cavity is formed by compacting sand into a mold box (orflask) around the pattern. The pattern is then removed from the newly formed mold cavity. Once molten metal has been poured and allowed to cool, sand is removed to reveal the final casting. Finished surfaces are not as smooth as with other methods, and additional machining, including the removal of gates and risers, is typically required. Sand casting is one of the most common methods used by foundries; it can be used for both short- and long-run productions.
Combination of metals which may contain other non-metal elements. Alloys are typically produced to achieve desirable material properties related to strength, hardness, corrosion resistance, conductivity, melting point and cost.
Non-ferrous metal that is notably lightweight and corrosion-resistant. Its low melting point makes aluminum highly castable. Aluminum is commonly alloyed with copper, zinc, magnesium, manganese and silicon.
Steel that contains 0.12-2.0 percent carbon and up to 10.5 percent alloy content. Carbon steels are often categorized as either high carbon or low carbon. High carbon content increases hardness at the expense of ductility, and vice versa. Carbon steels do not include stainless steels.
Group of iron alloys that contain approximately 2-4 percent carbon along with 1-3 percent silicon and other trace elements. Most cast irons, with the notable exception of malleable cast iron, are brittle. White cast iron and gray cast iron are widely used for their castability, machinability and resistance to wear.
A modern iteration of cast iron; ductile iron has superior ductility and impact resistance. Ductile iron is made using small amounts of magnesium or cerium to manipulate carbon into spherical formations that wont crack under stress. Also referred to asductile cast iron,nodular cast iron,spheroidal graphite ironandspheroidal graphite cast iron.
Steel that contains 10.5-30 percent chromium. The high chromium content provides stainless steel with natural corrosion resistance. Chromium oxidizes to form a non-reactive barrier that protects the internal structure. Numerous grades of stainless steel incorporate alloy ingredients such as nickel, molybdenum, titanium, aluminum, copper, nitrogen, sulfur, phosphorous and selenium.
Steel that has been alloyed with elements in addition to carbon to achieve desirable properties related to strength, hardness, and resistance to wear and corrosion. Common ingredients include manganese, nickel, chromium, molybdenum, vanadium, silicon and boron.
Engineering drawing that shows the final shape of a part to be cast. It includes all information related to dimensions, tolerances, machining and any other data necessary to determine foundry procedures.
Insert used to create mold cavities and openings that cannot be formed using a pattern on its own. Cores are often formed from molding sand to ensure adequate strength, hardenability and removability during shakeout. Cores will increase the cost of a casting and should be used only when necessary.
Process for removing unwanted gasses from casting materials, typically by pumping a neutral gas through molten metal. Unwanted gases form in metal castings through mechanical entrapment or by chemical reactions within liquid metal. If not removed, unwanted gases can create porosity in metals, which can compromise strength and integrity.
Taper applied to a patterns vertical surfaces. The taper facilitates clean and easy removal of a pattern from a mold. Minimum section thicknesses should be maintained when including drafts in pattern designs.
Container, comprised of two halves, a cope and drag, used to form sand molds. A pattern is placed inside the flask, typically fastened to a match plate, and packed with sand. The cope and drag are separated, the pattern is removed and the two parts are reassembled to form the mold cavity.
Channel that carries molten metal between mold cavities that would be otherwise separated. Gates are formed into a mold extraneous of the desired final product and must be removed by machining once a casting has cooled.
Type of sand casting characterized by the use of a wet sand mixture to create a mold. Dry sand molds are limited in the amount of weight they can support; green sand molds can support a much higher mass. In addition to water, bentonite, clay, and anthracite are normal components of green sand mixtures.
Pattern free from any mounting plate, which results in castings with minimal gates and risers. Loose, or unmounted, patterns are rarely used by foundries, except for prototypes and very large castings.
Pattern fastened to a board or match plate, which can then be fixed into a flask. Mounted patterns allow for quicker and better-quality mold making, while also allowing groups, or sets, of parts to be formed in a single mold.
Seam formed between cope and drag portions of a mold, where additional material may accumulate and show as a raised line, calledflashing, on a casting. Machining can be used to minimize or remove the appearance of a parting line.
Object made in the shape of the object to be cast. Patterns are used to form the mold cavities into which molten metal will be poured. They can be made into a single piece or split patterns comprising upper and lower sections.
Reservoir cavity included in the design of a mold to counteract the effects of material shrinkage during cooling. As casting materials shrink they draw additional material from risers to prevent cavity formation. Risers should cool and solidify with the slowest components of a castingusually the thickest and largest partand should contain enough material to compensate shrinkage.
Permissible range of variation, given in nominal dimensions, for a finished product. Accepted tolerances are typically agreed upon by both supplier and customer, and should be indicated in casting drawings.Get in Touch with Mechanic