Process flow

1. Crushing and prehomogenization
(1) In the process of cement production, most raw materials should be broken, such as limestone, clay, iron ore and coal. Limestone is the production of the largest amount of cement raw materials, mining after the granularity is larger, higher hardness, so limestone crushing in cement factory material crushing occupies an important position.
(2) Prehomogenization of raw materials Prehomogenization technology is to realize the preliminary homogenization of raw materials in the process of storage and taking of raw materials by using scientific stoking and taking technology, so that the storage yard of raw materials has both storage and homogenization functions.

2. Preparation of raw materials
In the cement production process, at least 3 tons of materials (including a variety of raw materials, fuel, clinker, mix, gypsum) should be pulverized for every 1 ton of Portland cement. According to statistics, the power consumption of grinding operation of dry cement production line accounts for more than 60% of the power of the whole plant, including more than 30% of raw material grinding, about 3% of coal grinding, and about 40% of cement grinding. Therefore, reasonable selection of grinding equipment and process, optimization of process parameters, correct operation, control of operation system, to ensure product quality, reduce energy consumption has great significance.

3. Homogenization of raw materials
In the process of new dry cement production, the stable raw material composition into the cellar is the premise of stable clinker firing thermal system, and the raw material homogenization system plays the last role of the stable raw material composition into the cellar.

4, preheat decomposition
The preheating and partial decomposition of raw materials are completed by the preheater, replacing part of the function of the rotary kiln, so as to shorten the length of the return kiln. At the same time, the gas and material heat transfer process is carried out in the stacked state in the kiln and moved to the internal suspension state of the preheater, so that the raw materials can be fully mixed with the hot gas discharged in the kiln, increasing the gas-material contact area, fast heat transfer speed and high heat exchange efficiency. To improve the production efficiency of kiln system and reduce the heat consumption of clinker firing.
(1) Material dispersion
80% of the heat transfer is carried out in the inlet pipe. Raw material fed into the preheater pipeline, under the impact of high speed updraft, the material turns upward with the airflow, and is dispersed at the same time.
(2) gas-solid separation
When the air flow carries the powder into the cyclone, it is forced to rotate and flow in the annular space between the cyclone cylinder and the inner cylinder (exhaust pipe), and it moves downward while rotating. From the cylinder to the cone, it can be extended to the end of the cone, and then it turns to rotate up and discharge from the exhaust pipe.
(3) predecomposition
The emergence of predecomposition technology is a technological leap of cement calcination. It is to add a calciner between the preheater and the rotary kiln, use the kiln tail rising flue, and set a fuel injection device, so that the heat release process of fuel combustion and the heat absorption process of carbonate decomposition of raw material can be carried out rapidly in the calciner in the suspension state or fluidized state, so that the decomposition rate of raw material into the kiln can be increased to more than 90%. The carbonate decomposition task originally carried out in rotary kiln is moved to the decomposition furnace. Most of the fuel is added from the calcination furnace, and a small part is added from the kiln head, which reduces the heat load of the calcination belt in the kiln, prolongs the life of the lining material, and is conducive to large-scale production. Since fuel and raw material are mixed evenly, fuel combustion heat is transferred to the material in time, which optimizes the combustion, heat transfer and carbonate decomposition processes. Therefore, it has a series of excellent performance and characteristics such as high quality, high efficiency and low consumption.

4. Burning of cement clinker
After the raw material is preheated and predecomposed in the cyclone preheater, the next step is to enter the rotary kiln for clinker firing.
In the rotary kiln, carbonate is further decomposed rapidly and a series of solid reaction occurs to produce minerals such as,, and in cement clinker. As the material temperature rises nearly,,, and other minerals will become liquid phase, dissolved in the liquid phase and react to produce a large number of (clinker). After the clinker is fired, the temperature begins to drop. Finally, the high temperature clinker discharged from the rotary kiln is cooled by the cement clinker cooler to the temperature that can be borne by the downstream conveying, storage and cement mill. At the same time, the sensible heat of the high temperature clinker is recovered to improve the thermal efficiency and clinker quality of the system.

5, cement grinding
Cement grinding is the last process of cement manufacturing, but also the most electricity consumption process. Its main function is to grind cement clinker (and gelling agent, performance regulating materials, etc.) to the appropriate particle size (expressed by fineness, specific surface area, etc.), form a certain particle distribution, increase the hydration area, accelerate hydration speed, to meet the requirements of cement slurry condensation and hardening.

6. Cement packaging
Cement factory has bag and bulk delivery two ways.
The decomposing furnace outside the kiln is set up to make full use of the waste heat discharged in the kiln, so as to preheat raw materials and achieve the decomposition of most calcium carbonate in advance, so as to achieve the purpose of energy saving, consumption reduction and improvement of calcining efficiency.