Cement production line is composed of a series of equipment for producing cement. It mainly consists of crushing and pre-homogenization, raw material grinding and homogenization, preheating and decomposition, cement clinker burning, cement grinding and packaging.
What are the equipment involved in a typical cement production line?
The configuration of cement production line usually includes jaw crusher, ball mill, rotary kiln, cement mill, raw material mill, coolant, dryer, air-swept coal mill, suspension preheater, decomposition furnace, dust removal device, belt conveyor, chain bucket conveyor and other equipment.
What are the features of cement production plant?
| Feature | Description |
| High Production Efficiency | The entire production process is highly automated, reducing manual intervention and increasing efficiency. |
| Low Energy Consumption | Utilizes advanced heat recovery and energy-saving technologies to effectively reduce energy consumption. |
| Stable Quality | Ensures consistent and stable product quality through precise control of process parameters. |
| Strong Equipment Reliability | Made with high-quality materials and advanced manufacturing processes, resulting in low maintenance needs and reliable operation. |
| Excellent Environmental Performance | Reduces emissions through an efficient flue gas treatment system, complying with environmental regulations. |
| Automated Control | Implements PLC and DCS systems for centralized monitoring and automated operation of the production process. |
| Flexible Adaptability | Capable of adjusting to different raw materials and product requirements, offering good production regulation capabilities. |
| Low Pollution Emissions | High-efficiency dust removal systems ensure low dust concentration in emissions, meeting environmental standards. |
What is the process flow of a 5000 tpd cement production line?
- Raw material preparation system: Tongli has mature and advanced limestone crushing technology. After limestone is mined, it needs to be coarsely and finely crushed. Tongli uses roller presses, jaw crushers, hammer crushers, impact crushers, etc. to crush limestone into particles less than 60mm.
- Raw material homogenization and storage system: In order to make the crushed materials uniform, the raw materials need to be homogenized. Tongli has two raw material homogenization systems. One is homogenization in the yard and the other is homogenization in the material warehouse. There are also two yards for customers to choose from, round or rectangular.
- Batching system: After crushing, the limestone raw materials need to be mixed with other raw materials. Tongli uses high-precision electronic belt weighing scales to proportion the raw materials according to the composition requirements of different grades of cement. The whole system is also equipped with a good dust removal system to ensure the cleanliness of the unloading area.
- Material grinding system: Tongli's unique grinding system is the key to ensuring the quality of cement. Tongli provides a variety of raw material limestone grinding solutions. The vertical mill occupies a small area, can be placed in the open air, and has low power consumption per ton. In recent years, it has become the first choice for many cement plants. Ball mills have large processing capacity and uniform particle size, and are also a good choice. The application cases of roller presses have been increasing in recent years, but there are certain requirements for humidity. The vertical mill has its own drying system to handle materials with high moisture content, and the ball mill can add a drying system to handle materials with high moisture content. Ball mills and cement vertical mills are the best choices for raw material grinding, which combine drying and crushing in one.
- Homogenization system: After grinding, the raw materials need to be homogenized again to ensure that the chemical composition is stable and meets the quality requirements.
- Preheating system: The raw materials need to be preheated before entering the rotary kiln. The coal injection pipe in the decomposition furnace heats the raw materials and decomposes 65% of the materials before formal calcination. The bucket elevator lifts the material to the top of the preheater, and the 5-level cyclone preheats the raw materials through the flue gas at the end of the kiln to save energy.
- Rotary kiln clinker calcining system: Raw material powder is fed into the kiln cylinder from the feed pipe at the high end of the kiln tail cylinder. Due to the inclination and slow rotation of the kiln cylinder, the material undergoes a compound motion of rolling along the circumferential direction and moving from high temperature to low end along the axial direction. Raw materials are decomposed and burned at a temperature of more than 1000℃ in the kiln, and then burned into cement clinker and discharged from the bottom of the kiln cylinder.
- Coal powder preparation system: Cement rotary kiln can choose a variety of heat sources. The common heat source is coal powder burner. Coal powder needs a preparation system to reach a certain fineness to meet the combustion conditions. Tongli provides coal powder preparation equipment for cement production line, vertical mill and air-swept coal mill ball mill. The coal vertical mill we produce has low power consumption and high quality. Its dust emission concentration is far lower than the environmental protection standard. Due to the flammable and explosive characteristics of coal powder, all our machines are equipped with CO, CO2 automatic monitoring, alarm and nitrogen fire extinguishing systems.
- Cement batching grinding system: According to the different requirements of cement performance, clinker needs to be measured with high precision, mixed with appropriate amount of gypsum and other materials, and then sent to cement mill for grinding. Tongli provides a variety of combined grinding systems, ball mill + roller press, clinker vertical mill, roller press grinding system, and fully considers the customer's on-site conditions for selection and design.
- Cement storage and distribution system: After cement is ground, it is stored in cement silos. After a series of strict chemical and physical tests, qualified cement can be sold as finished products. According to customer needs, there are two packaging methods, one is bagging, using cement 8-mouth packaging machine for 25kg or 50kg bags, or tons of bags. The other is bulk, the finished cement is loaded into tank trucks through pipelines.
What are the Necessary system for Dry-process Cement Production Line?
Cement production lines are divided into two processes: dry process and wet process. The earliest wet process of cement production was replaced by dry process in the 1990s due to high water evaporation and high heat consumption. Dry process of cement production is to grind the raw materials into powder and directly send them to the rotary kiln for calcination. The whole process does not involve the use of water. In the process of dry process of cement production, less water evaporates and lower heat consumption. The production line of dry process of cement consists of the following systems:
1. Raw material grinding system:
Raw material grinding station is responsible for grinding raw materials such as limestone, clay (or sandstone, siltstone), iron powder and other mixed materials, which play a key role in cement production. The process of raw material grinding is to overcome the stress of deformation and the cohesive force between particles through external forces such as impact, extrusion, grinding, etc., so that the block material is turned into fine powder. This process is crucial to the production of cement because it directly affects the quality and performance of the final product. The equipment used in the raw material grinding station includes horizontal mills and vertical mills (also called roller mills)
2. Coal powder grinding/pulverizing system:
Coal powder preparation is an important part of the active lime rotary kiln system, which usually includes two systems: one is a coal powder preparation system consisting of an air-swept tube coal mill and a bag dust collector, which has the advantages of simple operation and environmental protection. Its production process is as follows: coal blocks with a size of ≤25mm are fed into the belt through the process bucket elevator, and then enter the raw coal bin through the belt, and then fed into the coal mill through the disc feeder or electromagnetic vibrating feeder at the bottom. The equipment integrates grinding and drying. During the grinding process, hot air from the rotary kiln or hot flue gas from the auxiliary combustion chamber is introduced for drying. The ground coal powder enters the separation device under the action of the exhaust fan, and the coarse coal powder returns to the mill through the automatic ash discharge valve for re-grinding, while the fine powder enters the bag dust collector with the air flow to separate the dust. The gas after dust removal is discharged by the exhaust fan, part of the exhaust gas is recycled back to the coal mill for use, and the other part is discharged into the atmosphere through the chimney. The collected coal powder is sent to the coal powder storage bin in front of the kiln. According to needs, the coal powder is transported to the burner in front of the kiln through a Roots blower, and the burner combustion-supporting blower provides combustion air for calcining limestone.
3. Cement grinding station system:
The cement grinding station is the final stage of cement production, responsible for pulverizing cement clinker and appropriate mixed materials into finished cement. The entire cement production process can be divided into three main links: raw material preparation, clinker calcination and cement grinding. In the production of Portland cement, limestone and clay are the main raw materials. After the raw materials are lifted to the silo by the bucket elevator, they are sent to the hot air furnace through the dryer, and then lifted to the homogenization silo, and then enter the ball mill for grinding. Finally, the fine material is sent to the screw conveyor through the bucket elevator and transported to each cement silo. Each silo is equipped with a screw conveyor to facilitate the transportation of finished products
4. Limestone rotary kiln calcining system
The limestone calcining system consists of a vertical preheater, a rotary kiln, a cooler and other auxiliary equipment. The vertical preheater consists of a preheater body, a storage bin, a feed pipe and a hydraulic push rod device. It adopts a compartment partition design to gradually heat the limestone and reduce the risk of explosion and dust generation caused by a sudden temperature rise. The decomposition rate of the limestone entering the kiln can reach 30%-40%, and the average temperature of the exhaust gas is between 230℃ and 260℃, which effectively reduces the heat consumption. The structure of the rotary kiln includes a cylinder, a support device, a variable speed transmission device, a wheel block device, a kiln tail and a kiln head sealing device, etc. The kiln body is tilted 3.5 degrees and is equipped with two sets of support systems. The support wheel bearings are lubricated with water-cooled grease and have an automatic self-aligning function. A hydraulic wheel block is provided near the large gear ring, and the kiln body is driven by a variable frequency speed regulating motor and is equipped with an auxiliary transmission device to improve reliability. The kiln head and kiln tail are sealed with spring sheets. Combined with the decomposition rate of the preheater, the calcination time and temperature can be effectively controlled to meet the requirements of raw burning and over-burning. The burner adopts a four-channel gas mixed combustion design and has a flexible adjustment function. It can adjust the air injection speed according to different kiln conditions and facilitate the control of the calcination temperature in the kiln.
5. Raw material conveying system:
The raw material conveying system is mainly responsible for transporting the crushed limestone and dolomite to the cement plant. The raw materials are first transported to the storage warehouse by forklifts, and then transferred to the raw material warehouse by lifting devices. After metering, qualified limestone powder with a particle size range of 10-50mm is transported to the top warehouse of the preheater by bucket elevators to ensure that the finished product particle size is between 5-40mm and the qualified rate exceeds 90%. The conveying system also includes scraper conveyors, screw conveyors, etc.
6. Clinker cooling system
- The vertical cooler consists of a cooler body, a fixed screen, a cold air device and an electric vibrating discharger. It is equipped with multiple cooling and discharge zones, and the discharge speed of each zone can be adjusted independently according to the material temperature. The cooling air is in direct contact with the hot lime inside the cooler, ensuring a good cooling effect and a low ash discharge temperature. After the cooling air is cooled by lime at a temperature about 40°C higher than the ambient temperature, the temperature can be raised to more than 600°C. One part is used for secondary combustion of the rotary kiln, and the other part is used for drying coal powder. Since the cooler has no moving parts, the structure is simple and the maintenance requirements are low.
- The grate cooler is a quenching cooler. After the clinker enters the cooler from the kiln, a certain thickness of material layer is laid on the grate plate. The cold air blown in passes through the moving material layer on the grate bed in a perpendicular direction to quench the clinker, which can quench the clinker from 1300-1400°C to below 100°C in a few minutes. Traditional grate coolers are divided into three types: rotary, vibrating and push-type. However, since the first two have been eliminated, push-type grate coolers have become the main type of cement clinker cooler used in off-kiln decomposition kilns. The grate bed is the main component of the cooler, and the push-type grate plate is composed of fixed grate plates and movable grate plates arranged in rows.
7. Finished product conveying system:
The finished cement clinker passes through the grate cooler and is conveyed to the elevator by the chain bucket conveyor, and then to the top of the silo by the bucket elevator. After screening, qualified products with a particle size greater than 5mm are sent to the finished product silo by the belt conveyor, while powder materials less than 5mm are sent to the powder silo. There is an electric discharge valve under each silo. The finished product silo mainly plays the role of buffering and metering to ensure that the finished products can be delivered to the steel plant and calcium carbide plant in time to reduce the phenomenon of powderization.
8. Dust removal system：
The high-temperature flue gas generated by the combustion of the rotary kiln first exchanges heat with the limestone in the preheater, and the temperature is reduced to below 260℃. Subsequently, the flue gas is cooled by a multi-tube cooler and then enters a high-temperature bag filter for filtration. The treated flue gas is discharged into the atmosphere through a high-temperature fan, and the dust concentration is less than 30mg/Nm³, which meets the requirements of modern active lime production lines. This system ensures the reliable operation of the equipment, stabilizes the process parameters, guarantees product quality, saves energy, and improves production efficiency. The entire line adopts advanced technology, combined with PLC and DCS control, to achieve centralized monitoring and operation, improve the reliability and maintainability of electronic control equipment, and promote the modernization of control and monitoring.
What is Cement manufacturing process?
Phase 1: Raw material aquisition
Step 1: The main raw materials required for cement production include limestone, clay, corrective raw materials and auxiliary raw materials. Among them, limestone is the most important raw material, mainly providing calcium oxide (CaO), which usually accounts for 80% of cement raw materials. Clay provides silicon dioxide (SiO2), bauxite (Al2O3) and a small amount of ferric oxide (Fe2O3), while corrective raw materials are used to supplement the deficiencies of other ingredients. Auxiliary raw materials such as mineralizers, solvents and grinding aids also play an important role in production. In addition to limestone, cement production also uses other raw materials such as clay, fly ash, iron ore and coal. The quantities of these materials required in the entire production process are relatively small and can usually be purchased directly from suppliers.
Cement plants are usually built near limestone quarries so that the mined limestone can be transported directly to the plant through belt conveyors or other conveying systems. If the quarry is far away from the cement plant and conveyors cannot be used, trucks are needed for transportation, which not only increases costs but also causes inconvenience. Therefore, cement plants close to quarries can effectively save transportation and fuel costs, making the production process more economical. Before the raw materials are transported to the cement plant, they are first broken into smaller pieces using crushers at the quarry. Small pieces are easier to load, transport and process than larger pieces.
Phase 2: Batching/mixing/grinding
Limestone samples from the quarry are first sent to the cement plant's laboratory for testing and analysis to formulate a batching plan. A reasonable ratio of limestone to other raw materials is an indispensable step before grinding. The ratio of cement raw materials is not fixed, but should be adjusted according to specific conditions. The ratio of raw materials required for different types of cement is also different. Generally speaking, the composition of cement raw materials is about 67-75% limestone, 10-15% clay, 0.5-1.5% iron ore and 8.5-11% coal. The raw materials are mixed and further ground into finer raw material blocks in the cement plant with the help of vertical roller mills or other types of mills. In roller mills, rotating rollers continuously run on the grinding table to crush the material into fine powder, thus completing the grinding process. The ground raw material will be stored in a pre-homogenization pile for subsequent use.
Phase 3: raw meal preheating
The preheater of a cement plant is one of the key equipment in the cement production line, used for preheating and pre-decomposing the raw materials. It is located between the cement kiln and the burner, and plays a role in improving thermal efficiency and reducing energy consumption. During the operation of the preheater, due to the volatile substances in the raw materials being decomposed under high temperature conditions and the accumulation of particulate matter on the inner wall of the preheater, a thicker solid substance is attached to the inner wall surface of the preheater, forming a hard outer layer.
Phase 4: Calcination process
Limestone is mainly composed of calcium carbonate, which decomposes into calcium oxide and carbon dioxide at high temperatures. This process is called calcination and is a key step in cement production. Next, we need to mix clay and iron powder with limestone powder. The mixing ratio of these raw materials will directly affect the characteristics and quality of the final cement produced. After that, the mixture will be calcined by dry or wet methods to make clinker. Dry calcination means heating the mixture directly to high temperature in the kiln, while wet calcination means stirring the mixture into mud in water before heating and calcining it in the kiln. No matter which method is used, the purpose is to fully sinter the mixture at high temperature to form the clinker we need.
Phase 5: Clinker cooling
The main function of the grate cooler is to cool the high-temperature clinker fired from the cement kiln during transportation, so that it can be cooled to a suitable temperature range for subsequent maturation and processing. More importantly, the grate cooler can also use the waste heat generated during the cooling process to complete the heating of processes such as hot blast furnaces, raw material mills and conveying systems to achieve the purpose of energy recovery and conservation. The main working principle of the grate cooler is to achieve self-cooling of the entire machine by relying on a large amount of production line materials. Specifically, the hot and cold gases are heat exchanged and cooled under the joint action of important devices such as preheating furnaces and baking furnaces, and finally the clinker is quickly cooled. At the same time, the cooling gas driven by the main engine can also be recycled through heat exchangers and coolers to achieve the purpose of energy reuse and energy saving.
Phase 5: Final Grinding
Cement grinding is the last process of cement manufacturing and also the process that consumes the most electricity. Its main function is to grind cement clinker (and retarder, performance adjustment material, etc.) to a suitable particle size (expressed by fineness, specific surface area, etc.), form a certain particle gradation, increase its hydration area, accelerate the hydration rate, and meet the requirements of cement paste coagulation and hardening. Cement grinding can be divided into the following according to the process flow: 1. Open circuit grinding system, 2. Closed circuit grinding system, 3. Combined grinding system. According to the use of equipment, it can be divided into: 1. Ball mill grinding system, 2. Vertical mill final powder system, 3. Vertical mill-ball mill combined powder system, 4. Roller press final powder system, 5. Roller press-ball mill combined grinding system, 6. Horizontal roller mill (Horomill) grinding system.
How much is the cost of producing one ton of cement?
| Item | Unit Price ($/ton) | Usage (kg/ton) | Cost (USD) | Remarks |
| Limestone | 6.85 | 1400 | 9.59 | Main raw material for cement, ~70% of total |
| Clay | 5.48 | 200 | 1.10 | Auxiliary material, ~15% of total |
| Iron Ore | 95.89 | 30 | 2.88 | Adjusts iron content |
| Gypsum | 41.10 | 50 | 2.06 | Regulates cement setting time |
| Slag Powder | 27.40 | 100 | 2.74 | Increases strength, reduces clinker ratio |
| Energy Consumption | ||||
| Electricity Consumption | 0.09 USD/kWh | 100 kWh | 8.90 | Around 100 kWh per ton of cement |
| Fuel (Coal/Natural Gas) | 136.99 USD/ton | 120 kg | 16.44 | Around 120 kg of fuel per ton of cement |
| Others | ||||
| Labor Costs | Fixed | - | 6.85 | Assumed annual salary and operational costs |
| Equipment Depreciation | Fixed | - | 4.11 | Depreciation amortized per ton |
| Environmental Fees | Fixed | - | 1.37 | Costs for environmental management |
| Total | - | - | 55.04 | Total production cost per ton of cement |
