Cement production process
Those who know a little about the cement production process, mentioning the production of cement, will say "two mills and one burn", they are: raw material preparation, clinker calcination, cement grinding. For some of these process requirements, this website is collected and organized for your reference.
Any fine grinding material, adding appropriate amount of water, into a plastic slurry, that is, a hydraulic cementing material that can harden in the air and harden in water, and can firmly bond together materials such as sand and stone. . In general, the cement industry produces Portland cement, a fine, usually gray powder of calcium (from limestone), silicates, aluminates (clay) and iron. Acid salt composition. In a Portland cement plant, cement production has the following main stages:
Limestone is the main raw material for cement production. Most of the factories are located near limestone quarries to minimize transportation costs. 1. Extraction of raw materials (limestone, shale, silica and pyrite) by blasting or using a cutting machine. 2. The raw material is sent to the crusher where it is broken or hammered into pieces. 3, crushed limestone and other raw materials are usually covered to protect from the external environment, while minimizing dust. 4. In most cases, quarries and cement plants will require separate or separate power supplies.
Raw material mill:
1. In the raw material grinding workshop, the raw materials are ground finer to ensure high quality mixing. 2. Vertical mills and ball mills are used at this stage. The former uses the pressure of the drum to smash the passing material, while the latter relies on the steel ball to grind the material. 3. To date, most of the electrical energy consumed by the raw mill has not been used to break up the material, but has been converted into heat loss. Therefore, there is an economical demand here, and it is hoped that the raw mill workshop can be adjusted to keep the energy loss as low as possible. 4. It is necessary to use an electrical automation system that optimizes the grinding process. 5. The raw meal is finally transported to the homogenization yard for storage and further material mixing.
1. The diameter of the clinker spherical agglomerates must be in the range of 0.32-5.0 cm, which are generated in the chemical reaction between the raw materials. 2. The high temperature processing system consists of three steps: drying or preheating, calcining (primary heat treatment, calcium oxide formation in the process) and calcination (sintering). 3. Calcination is the core part of this process. The raw meal is continuously weighed and fed to the cyclone at the top of the preheater. The material in the preheater is heated by the rising hot air. In the large rotary kiln, the raw material is converted into clinker at 1450 degrees Celsius. 4. The clinker enters the grate cooler from the kiln head for thermal regeneration and cooling. The cooled clinker is then transferred to the clinker bin for storage using a tray conveyor. 5. After clinker is cooled, it can be transported on the conveyor belt and can regenerate up to 30% of heat. The cooling air sent through the clinker is introduced into the rotary kiln, which facilitates fuel combustion. The general type of grate coolers are reciprocating grate, planetary and rotary. The very rough dust collected by the grate cooler consists of cement minerals, which are recycled for reprocessing. 6. Depending on the cooling efficiency and the desired cooling temperature, the amount of air used during the cooling process is approximately 1-2 kg/kg clinker. If a portion of the gas is used in other processes, such as coal drying, after the cooling process, the amount of gas that needs to be purified can be reduced. 7. Clinker storage capacity can be based on market considerations. A factory can usually store 5-25% of the annual output of clinker. Equipment such as conveyor belts and bucket elevators can be used to transfer clinker from the grate cooler to the storage area and between the clinker mills. Gravity drops and transfer points are usually provided with ventilation to the dust collector. 8. The main requirement for low loss and low energy consumption is to achieve a balanced operation of the rotary kiln. Therefore, modern process control techniques must be used to continuously monitor the combustion process.
Storage and clinker grinding:
1. Clinker is taken out from the clinker silo and sent to the silo, and mixed with gypsum and additives before entering the clinker mill. 2. During the clinker grinding process, the clinker and other raw materials are ground together into fine powder, and up to 5% of gypsum or additional anhydrite is added to control the solidification time of the cement, and other additions are added. A compound, for example, a compound used to adjust fluidity or gas content. Many plants use a roller crusher to obtain clinker and gypsum that can be reduced to a predetermined size. These materials are then fed into a ball mill (rotary, vertical steel cylinder containing steel alloy balls) for the remaining grinding process. 3, the grinding process is sealed.