The raw cement ingredients needed for cement production are limestone (calcium), sand and clay (silicon, aluminum, iron), shale, fly ash, mill scale and bauxite. The ore rocks are quarried and crushed to smaller pieces of about 6 inches. Secondary crushers or hammer mills then reduce them to even smaller size of 3 inches. After that, the ingredients are prepared for pyroprocessing.
The crushed raw ingredients are made ready for the cement making process in the kiln by combining them with additives and grinding them to ensure a fine homogenous mixture. The composition of cement is proportioned here depending on the desired properties of the cement. Generally, limestone is 80% and remaining 20% is the clay. In the cement plant, the raw mix is dried (moisture content reduced to less than 1%); heavy wheel type rollers and rotating tables blend the raw mix and then the roller crushes it to a fine powder to be stored in silos and fed to the kiln.
A pre-heating chamber consists of a series of cyclones that utilizes the hot gases produced from the kiln in order to reduce energy consumption and make the cement making process more environment-friendly. The raw materials are passed through here and turned into oxides to be burned in the kiln.
The kiln phase is the principal stage of the cement production process. Here, clinker is produced from the raw mix through a series of chemical reactions between calcium and silicon dioxide compounds. Though the process is complex, the events of the clinker production can be written in the following sequence:
The kiln is angled by 3 degrees to the horizontal to allow the material to pass through it, over a period of 20 to 30 minutes. By the time the raw-mix reaches the lower part of the kiln, clinker forms and comes out of the kiln in marble-sized nodules.
After exiting the kiln, the clinker is rapidly cooled down from 2000C to 100C-200C by passing air over it. At this stage, different additives are combined with the clinker to be ground in order to produce the final product, cement. Gypsum, added to and ground with clinker, regulates the setting time and gives the most important property of cement, compressive strength. It also prevents agglomeration and coating of the powder at the surface of balls and mill wall. Some organic substances, such as Triethanolamine (used at 0.1 wt.%), are added as grinding aids to avoid powder agglomeration. Other additives sometimes used are ethylene glycol, oleic acid and dodecyl-benzene sulphonate.
The heat produced by the clinker is circulated back to the kiln to save energy. The last stage of making cement is the final grinding process. In the cement plant, there are rotating drums fitted with steel balls. Clinker, after being cooled, is transferred to these rotating drums and ground into such a fine powder that each pound of it contains 150 billion grains. This powder is the final product, cement.
Cement is conveyed from grinding mills to silos (large storage tanks) where it is packed in 20-40 kg bags. Most of the product is shipped in bulk quantities by trucks, trains or ships, and only a small amount is packed for customers who need small quantities.
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With the emphasis on environmental protection increasingly , the use of fly ash in industrial production is increasingly mentioned , vertical milling machine that used for the processing of fly ash has been widely used .
Vertical milling machine Main features include: investment costs low ; low operating costs ; strong drying capacity ; simple, reliable operation ; stable product quality ; easy maintenance ; safety, environmental protection , to meet national environmental requirements. Currently, it has demonstrated the ability of vertical milling machine in Fly ash processing industry to use actual, It has been the milling experts in Fly ash processing industry !
LM vertical grinding mill used in the processing of fly ash powder vertical milling machine is mainly used for fly ash ultrafine powder processing, powder processed through the ash can be secondary combustion , some containing metal elements the ash can be spun off , greatly contributed to the re-use of fly ash .
Fly ash is the fine ash collected from flue gas after combustion of power plant boilers. The main components are silica, aluminum oxide and a small amount of ferric oxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide and sulfur oxide. Large amount of coal consumption produces large amount of fly ash. In terms of mineralogy, fly ash is mainly composed of vitreous and crystalline phases, and also contains a certain amount of unburned carbon. The vitreous component is mostly aluminosilicate vitreous, usually accounting for more than 60% of the mass fraction of fly ash. The crystalline components of fly ash are mainly mullite, quartzite and iron ore, in which the proportion of mullite is the largest, accounting for about 6%-15% of the total. Unburned carbon is generally not more than 5% in fly ash. In general, the smaller the fineness of fly ash, the smaller the burning loss, the larger the specific surface area, the more active sites and the higher the activity. The fly ash with high activity is easy to react with other substances to generate new substances, which is suitable for resource utilization.
Used to make cement, concrete, brick and block. As a building material, fly ash has several characteristics: easy to analyze, spherical particles exist, can be matched with concrete, large amount of use, wide range of use and high degree of use. The use of fly ash in construction accounts for about 45% of the total utilization, the main products are: fly ash cement (mixing more than 30%), concrete, ordinary cement, wall materials, roadbed filler, silicate load-bearing block and small hollow block, sintered ceramic, sintering brick and so on.
Based on the absorption of advanced technologies of famous international corporations and 30 years' experience in grinding mill production, SBM has launched the LM Vertical Grinding Mill which integrates five functions of crushing, grinding, powder selection, drying and material conveying. It is characterized by centralized technological process, small occupational area, low investment, high efficiency, energy conservation and environment protection. Of course ,ball mill is also suitable for quartz grinding with high-quality final powder and big capacity.
Fly ash is the fine ash collected from the flue gas after coal combustion. It is the main solid waste discharged from coal-fired power plants. Its annual output is large, which has great harm to the environment and human health. And its particle distribution is very uneven, so it usually needs to be ground to improve its performance to be put into secondary use. As a kind of industrial waste, fly ash is rich in resources, low in price, and contains a lot of active ingredients. After classifying and grinding, it can replace clay to become the raw material for producing cement clinker, and can also be used as an admixture of concrete to save a lot of cement and fine aggregate. The fly ash processing plant constructed by AGICO Cement is highly automated and mechanized, with low investment, high profit, simple structure and easy operation, which helps each region realize reasonable waste recycling and utilization to green up users supply chains.
The first step of the fly ash processing system is taking ash from the silo and sending it into the elevator in front of the grinding mill after feeding by the feeder and electronic weighing. Then the fly ash will be fed into powder concentrator for the first classifying. During the classifying, qualified fine ash enters the fine ash silo through conveying chute, while the coarse ash is sent to the cementball mill for fine grinding. After grinding, the pulverized fly ash needs to be classified again in the powder concentrator. The fine ash that meets the requirements is sent to the fine ash silo through the conveying equipment, and the coarse ash is sent back to the ball mill for secondary grinding. The whole system is equipped with a dust collector. There is no need to worry about dust pollution.
This fly ash classifying system is developed by our researchers according to years of practical operation experience. It is a closed-circuit circulation classifying system with high efficiency and adjustable turbo-type powder concentrator as the main equipment. This system has the advantages of clear design principle, simple structure, small workload of operation and maintenance, being widely used in fly ash processing plants.
The fly ash ball mill is the special equipment for fly ash grinding, which is designed and developed by our company after years of research and practice. It is the most ideal equipment for further processing of fly ash.
AGICO Cement has large manufacture workshops and professional processing equipment to ensure the fast and high-quality production of related equipment in this fly ash processing plant. In addition, we have more than 20 years of production and sales experience, the products are exported to all over the world, therefore, we can ensure the timely and safe delivery, reducing the time cost of customers.
AGICO provides EPC turnkey projects. It not only includes the manufacture of various specialized equipment in the fly ash processing plant but also includes the fly ash processing plant design, onsite installation, real-time commissioning, equipment operation training and usual spare parts service.
Customization is the most basic service our company provides for each customer. We will design the fly ash processing plant according to customers specific needs, such as capacity, fly ash standard, construction environment, etc. Every customer will get their own satisfied plant here.
This fly ash processing plant is equipped with advanced dust collector to strictly control dust emission and noise pollution, realizing the reuse of resources, so you dont need to worry about the environmental issue.
After grinding, the fly ash can be used as a partial substitute for concrete raw materials. Different incorporation of fly ash will affect the hardening level, strength, dry shrinkage and other characteristics of concrete, with an ideal content of 40%. Using fly ash as raw material to make cement has been quite common in cement plants, and the technology is relatively mature. The ideal content can reach 75%.
Fly ash, aggregate, cement and other raw materials can be made into different types of concrete blocks through batching, mixing, molding, curing and other processes, such as fly ash concrete hollow block, fly ash brick and so on.
High purity alum can be extracted from fly ash to synthesize bauxite. Making fly ash as raw material, SiC powder, a non-oxide ceramic material, which is widely used in the market, can be synthesized by carbothermal reduction synthesis method. The fly ash can be made into polymer filling material after some refinement processing.
Fly ash is rich in microelements, such as silicon, boron, sulfur, zinc, copper, calcium, magnesium, iron, etc. It has loose texture and can improve the soil structure. If we mix some additives with fly ash according to a scientific formula, we can make compound fertilizer.
AGICO Group is an integrative enterprise group. It is a Chinese company that specialized in manufacturing and exporting cement plants and cement equipment, providing the turnkey project from project design, equipment installation and equipment commissioning to equipment maintenance.
What is the processing method of fly ash? What finished products can fly ash be made after processing? HCM provides professional fly ash grinding mill machine equipment to provide customers with the best quality products and services.
Fly ash is the fine ash collected from the flue gas after coal combustion. It contains silica, alumina, iron oxide, ferric oxide, calcium oxide, titanium dioxide and so on, which is the main solid waste discharged from the power plant.
According to the proceedings of the National Academy of Sciences, fly ash enters the natural carbon cycle, is not easy to be oxidized, hinders rivers, pollutes the atmosphere with dust, and seriously affects the health of people and animals.
Fly ash processing for recycling has been studied by many scholars. In the early years, fly ash was widely used in masonry mortar and plastering mortar, but now it has a place in concrete, agriculture, ceramics and other fields.
In order to improve the utilization value of fly ash, the processing methods of fly ash are screening, grinding, screening + grinding combination. In the grinding equipment must find professional grinding equipment. HLMXseries superfine mill produced by HCMilling(Guilin Hongcheng)is a professional equipment for processing fly ash. It can catch up with foreign technology and replace imported superfine vertical mill. It is one of the ideal equipment for large-scale production of environmental protection and energy saving superfine powder.
Product characteristicIt integrates crushing, drying, grinding and conveying, breaking through the bottleneck of superfine powder processing capacity, can replace imported equipment, scientific and reasonable design and innovative structure, and is a large-scale production equipment of superfine powder.
Focusing areaIt focuses on large-scale grinding and processing of non-metallic minerals such as coal mine, cement, slag, gypsum, calcite, barite, fluorite, marble with Mohr hardness below 7 and humidity within 6%. The product has a number of patent technology, advanced performance.
If you are in need of any non-metallic grinding mill, contact [email protected] call at , HCM will tailor for you the most suitable grinding mill program based on your needs, more details please check www.hcmilling.com.
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Fly ash is a fine, powder-like material generated from coal-burning power plants. And despite an increase toward more sustainable energy production, coal-burning power plants are still prevalent, producing fly ash that could serve as a valuable commodity. Thus now is an important time as any to evaluate the way in which we look at this material, and consider it not a waste, but an opportunity for use in a multitude of industrial applications. Through conditioning and agglomeration technologies, fly ash can be transformed from a waste, to a more marketable product, forever giving meaning to the term waste-to-value.
While many sources of fly ash can lend themselves to more marketable products, not all is usable, and some samples should be landfilled. In these situations, conditioning or agglomerating fly ash prior to landfill is particularly advantageous in its own regard. Because fly ash is a fine powder, it can be very dusty and easily wind-blown, making it difficult to transport, as well as tough to manage at a landfill. Pre-conditioning or de-dusting the material makes it easier to transport and handle, and more stable for landfilling, so it does not end up blowing away into undesired areas. This stabilization may also help prevent toxic metals from leaching out of the fly ash.
The primary equipment used for processing, whether that be for landfill, or for a marketable product, includes pin mixers, paddle mixers, and disc pelletizers, with the equipment selection being dependent upon the desired end-product. If one is seeking fine agglomerates, less than 1 mm or 18 mesh, a pin mixer is the equipment of choice. For larger agglomerates, the paddle mixer, or pin mixer and disc pelletizer combination is the best option.
As mentioned, the end products intended use will often dictate which equipment is most suitable for the operation. Paddle mixers, for example, create a wide range of agglomerates, though not as uniform in shape as those produced by other agglomeration equipment. Fly ash processed for landfill would likely not require a uniform end product, and thus the paddle mixer would suffice as the equipment of choice. As a cement additive however, uniform particle size distribution may be very important, and a pin mixer/disc pelletizer combination would be better suited to achieve the desired end product characteristics.
Paddle mixers are composed of two shafts spanning the length of the mixer, each affixed with pitched paddles. The shafts rotate at a constant speed, in opposition to each other. The action of the paddles moves the fly ash from the top of the trough, down each side, and then back up the middle. This creates a kneading and folding over motion, ideal for thorough mixing. Additionally, in a fly ash application, the paddle mixer is fitted with a binder spray system that feeds in binder at a constant, specified rate. This, in combination with the motion inside the paddle mixer, thoroughly mixes and de-dusts the feed with the binder, creating a homogeneous mix.
Pin mixers can be used as a stand-alone device, or in combination with a disc pelletizer. Unlike a paddle mixer, pin mixers are comprised of a single shaft, fitted with rods, or pins. The shaft rotates at a constant, high speed, causing an intense spinning action inside the mixer. This spinning motion not only eliminates air and reduces water volume between the fly ash particles, but it also begins to form micro-pellets. These micro-pellets can be considered a finished product, or move on to further processing on the disc pelletizer. Again, a binder spray system is added to help de-dust the fly ash and promote the formation of micro-pellets. When used in combination with a disc pelletizer, these micro-pellets serve as an ideal starting point for creating premium fly ash pellets on the disc pelletizer.
Disc pelletizers, also known as pan granulators, use tumble growth agglomeration, a process where the material gradually rolls and builds against itself in the presence of a surface moisture and possibly a binder, in order to form round pellets. In this application, fly ash would exit the pin mixer and be fed onto the disc pelletizer at a constant rate, along with additional binder to increase tackiness of the material. As the disc rotates, the tacky micro-pellets roll against themselves, picking up additional fines, and essentially growing into larger pellets. Once pellets reach the desired size, they exit the disc pelletizer. Disc pelletizers are the equipment of choice when uniform pellets are of utmost importance.
The fly ash processing systems noted above are commonly performed in FEECOs lab. Because the materialcomposition varies from deposit to deposit and desired end-product use differs as well, our lab technicians may test single pieces of equipment or various combinations of equipment which may be required for processing. Testing in the FEECO Feasibility Lab is always recommended when processing fly ash, to become familiar with the nuances of each specific deposit.
FEECO has worked with fly ash since our founding in 1951. From that day forward, weve done everything from feasibility testing in the lab, to manufacturing custom processing systems and equipment. For more information on our experience with the material, or for help with your fly ash by-product, contact us today!Get in Touch with Mechanic