What is a clinker? Cement clinker is made of limestone, clay, and iron, these main raw materials are mixed in proper proportions, burned to partial or total melting, and finished cement is obtained by cooling. Portland cement clinker is mainly containing CaO, SiO2, Al2O3, Fe2O3, in accordance with the appropriate proportion of grinding into fine powder burning to partial melting, calcium silicate as the main mineral composition of the hydraulic cementation material. Among them, calcium silicate mineral is not less than 66%, and the mass ratio of calcium oxide to silicon oxide is not less than 2.0. What is the clinker used for? Cement grinding plant process clinker into the required size, and finished cement is obtained.
What is clinker plant? As we all know, cement production line can be generally divided into three main parts, raw material production, clinker production and finished cement production. Clinker plant is applied to clinker production, we can classify the clinker plant into two parts, preheat and precalcining, burning in the rotary kiln.
1.Preheater and pre-calcining
The preheating of raw material and part of precalcining are completed by preheater in cement plant, it plays partial roles of cement rotary kiln, shorten the length of rotary kiln, and remove the heat exchange from rotary kiln to preheater, which fully mix raw meal and hot air from rotary kiln, increase contact area between air and materials, improve the heat exchange efficiency, realize the goals of higher working efficiency and energy-saving.
In a word, the preheater in the cement plant makes full use of waste gas discharged from rotary kiln and precalciner to heat the raw meal and decompose partial carbonate. To maximize the heat exchange efficiency between gas and solid, and realize the high quality, high yield and low consumption of the whole calcination system, it is necessary for cyclone preheater to have three functions: uniform gas-solid dispersion, rapid heat exchange, and efficient separation.
Note: pre-calcining means that set precalciner between preheater and rotary kiln, transfer the decomposition inside rotary kiln into the precalciner, prolong the useful life of rotary kiln and it is good for the large-scale cement production. It is known with the advantages of high quality, high efficiency, low consumption and a series of excellent performance.
Cyclone preheater: preheater in cement plant use suspension preheat to complete the raw meal preheating and partial precalcining. The cyclone preheater reduces the energy consumption of the clinker plant, also reduces the occupied area.
2. Rotary kiln burning
After the raw materials are preheated and pre-calcining in the cyclone preheater, the next, the raw meal will be sent into the rotary kiln for the burning of the clinker. In the rotary kiln, the carbonate is further rapidly decomposed and a series of solid reactions occur to produce minerals in cement clinker. As the temperature of the material rises, the mineral will turn into a liquid phase, dissolve in the liquid phase and react to produce a large amount clinker. After the clinker burning, the temperature begins to drop. And then, the high-temperature clinker discharged from the rotary kiln is cooled by the clinker cooler to the temperature that can be accepted by the downstream transportation, cement storage silo, and cement mill, and the sensible heat of the high-temperature clinker is recovered to improve the thermal efficiency and clinker quality.
Cement rotary kiln: rotary kiln is the core equipment of the clinker plant that is used for clinker burning. According to the cement manufacturing process, rotary kiln can be divided into two types, dry-process cement rotary kiln, and wet-process cement rotary kiln.