What exactly is cement manufacturing process? Cement manufacturing process, also known as manufacturing of cement, which means the production process of cement manufacturing. In general, cement manufacturing is the premise of cement plants.
Before starting an excellent cement plant, it is necessary for a new beginner to learn cement manufacturing process first. So AGICO CEMENT who has plenty of experience in supplying cement plant and cement equipment will give you a full guide on cement manufacturing process.
6 steps of the cement manufacturing process
When we talked about the manufacturing of cement, anyone who knows the cement manufacturing process slightly will mention “two grinding and one calcination”, they are namely: cement raw material preparation, clinker production, and cement grinding.
In the real cement production line, we detail the cement manufacturing process in six steps, including crushing, raw meal grinding, homogenization, preheating and clinker production, cement grinding, packing and shipping.
Crushed limestone and other materials are usually stored overlaid to protect them from the environment and to minimize dust. In most cases, quarries and cement plants require separated or single power supplies.
Crushing of cement raw materials is a process to cut large particles into a smaller sizes. The raw material of cement usually include limestone, clay, shale, tripoli, and others, limestone is always the main composition, for reducing g the transportation cost, most cement plant would be located near the limestone quarry. After the raw material extraction by mining or getter loader, they are sent to the cement crusher that crushes all materials into smaller particles. According to the characters of raw materials, the jaw crusher and impact crusher or mobile crusher will be the best choice.
Raw meal grinding
After crushing, the qualified raw materials will be sent to pre-homogenization, and the humid materials will be dried firstly, and then sent to the pre-homogenization. You may ask what is pre-homogenization? Pre-homogenization refers that prepare crushed materials and corrective materials in a certain proportion.
In the raw meal grinding production, the cement raw materials will be ground into finer size to make sure good mixing. In this stage, there are two types of the raw mill to choose, the vertical cement mill uses the pressure leaked by cylinder to crush the passing materials. The cement ball mill use balls to grind the materials. From now on, the most energy consumed by the raw mill is converted into heat loss, not used to crush raw materials.
Next, the raw mix will be sent to the raw meal homogenizing silo for storing and further mixing. The stacker and reclaimer help to complete homogenization. Why homogenization is important? By combining the proportion of raw materials or mixing raw ingredients, the fluctuation range of raw materials is reduced, the qualified rate of raw materials into the cement kiln is improved, which is conducive to stabilizing the thermal system of the cement kiln and improving the production quality of the cement clinker.
Preheating and clinker production
The diameter of the clinker ball should between 0.32 and 5.0cm. The high-temperature treatment system includes preheating, calcination, and sintering, and calcination is the core of clinker production.
- The raw mix is continuously weighed and fed into the top of cyclone preheater, the material in the preheater is heated by rising hot air, and the material is converted into clinker in the cement rotary kiln at 1,450 degrees.
- The clinker enters the grate cooler from the kiln head for thermal regeneration and cooling. The cooled clinker is then transferred to the clinker silo by conveyor for storage.
- The clinker can be transferred on the conveyor belt after cooling and can regenerate up to 30% of the heat. Cooling air sent through the clinker is fed into the rotary kiln, which facilitates fuel combustion. The very coarse dust collected by the grate cooler consists of cement minerals, which are recycled and reprocessed.
According to the cooling efficiency and desired cooling temperature, the amount of air used in the cooling process is approximately 1-2 kg per kilogram of clinker. After the cooling process, some of the gas is used in other processes, such as coal drying, the amount of gas that needs to be cleaned can be reduced.
Clinker storage capacity can be considered based on market demand. A cement plant can usually store 5-25% of the annual clinker production. Cement equipment such as conveyor belts and bucket elevators can be used to transfer clinkers from grate coolers to storage areas and between clinker mills.
The main requirement for low dissipation and the low energy consumption is to achieve the balanced and consistent operation of rotary kiln. Therefore, the combustion process must be continuously monitored.
The clinker is removed from the clinker silo and sent to the feeding silo, where it is mixed with gypsum and additives before entering the cement mill.
During the cement grinding process, when the clinker is ground to a fine powder with other raw materials, up to 5% gypsum or additional anhydrite is added to control the solidification time of the cement. Many factories use a cement crusher to obtain the scheduled size of clinker and gypsum, which is then fed into a cement ball mill for the rest of the grinding.
The grinding process is carried out in a closed system, which is equipped with an air separator to separate cement particles according to size, and materials that are not completely finely ground are relayed through the system.
This energy-intensive process requires automation and optimized control to ensure current quality requirements.
Packing and shipping
The finished cement is stored in huge cement silos. Cement can be shipped to customers in bulk by trucks or cargoes, or bagged and sent in standard trucks.
When operating a cement plant, the delivery process is one of the most important tasks. Since shipping equipment is also commonly used for weighing and loading and unloading materials from external suppliers, these systems must support process control for feed transfer.