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Cement Production Line

Cement Production Process

Cement production process:
  1. Broken and pre-homogenization
  (1) Broken --- In cement production process, most of the raw materials demand to be broken, such as limestone, clay, iron ore and coal. Limestone is the largest amount raw materials for cement production. After mining, its particle size is larger and its hardness is stronger,so crushing limestone plays a important role in the materials' crushing of cement plant.
  (2) Raw materials' pre-homogenization --- pre-equalization technology is the stacker-reclaimer technology by using technology in the process of depositing and withdrawing raw materials to achieve raw materials' initial homogenization,which can make materials stockyard have two functions: storage and homogenization.
  2. Raw material preparation
  In cement production process, producing tons of portland cement should grind at least three tons of material (including a variety of raw materials, fuel, clinker, mixed materials, gypsum).According to statistics,theconsumption of  power for grinding operations of the dry cement production line is above 60% of the whole plant and raw materials grinding occupy above 30%, coal grinding occupy 3% and cement grinding occupy 40%. Therefore, it is a great significance for ensuring product quality and redusing energy consumption by the means of reasonable choice for grinding equipment and process, optimization of process parameters,correct operation and controling operation system.
  3. Raw meal homogenizing
In dry cement production process, stabilizing raw materials into the kiln is the premise for stabling clinker burning thermal system, Raw meal homogenizing system plays the final control role for stabling raw material into the kiln.
  4. Pre-heat and decomposition
  Preheaters complete the raw materials' preheating and partial decomposition,instead of some features of rotary kiln,which can shorten the length of kilns,transfer heart between gas materials in the accumulation state in the kiln,proceeding in the Suspended state by moving to preheater,which can make raw materials mixing with hot gas(which is exhausted by kiln), increasing the contact area of gas,transfering heat quickly,increasing heat exchange efficiency to achieve greater production efficiency of the kiln system and reduce the clinker heat consumption.
  (1) Material dispersed
  80% of heat exchange happen in the inlet pipe. The raw materials will be fed into the preheater moving up with gas and is dispersed at the same time in the impact of high-speed updraft gas.
  (2) Gas-solid separation
  When gas with material powder enters into the cyclone,it will be forced to rotation flow in the annular space between the body of the cyclone and the inner of the cylinder(exhaust pipe),spin at same time move downward,which can move from the cylinder to cone,and extend to the end of the cone,and then rotate up to discharge from the exhausting pipe.
  (3) Pre-decomposition
  The emergence of the pre-decomposition technique is a technological leap to cement calcining process. To add decomposing furnace between preheater and rotary kiln,use the rise fule in the end of the kiln and set fuel injection device can make the exothermic process of fuel burning and endothermic process of carbonate decomposition of raw material proceed quickly in the suspended state or fluidized state in the decomposingfurnace,which can increase resolution ratio of raw matarial to above 90%. The decomposition of carbonate happened in the rotary kiln moving to the calciner;Fuel is added from the decomposingfurnace and a small amount is joined from the head of the kiln.That can reduce the heat load of the calcination zone in the kiln and extend the life of ining.It is benefic to large-scale production;Due to materials and raw materials mix uniformity, the heat of fuel combustion can transfer heat to materials timely, which make burning, heat transfer,and decomposable process of carbonate optimize. Therefore, it has a series of good performance and features such as excellent quality, high efficiency, low power consumption,etc.
  4. Sintering of cement clinker
Raw materials complete pre-heating and precalciner in the cyclone preheater.The next process is that entering into rotary kiln to the sintering of clinker.In the rotary kiln, carbonate decompose rapidly and take place a series of solid-phase reaction to produce the mineral in the cement clinker.With materials' temperature rising,mineral could become liqiud, dissolved in the liquid phase and neutralization reaction take place to produce a lot of clinker.After clinker burning,the temperature begins to reduce. The high heat materials dischaged by the rotary kiln is cooled to the temperature that downstream conveying,stores and cement mill can be beared by the use of the cement clinker cooling machine,at the same time recover waste heat of the high heat material,which can increase the thermal efficiency and clinker quality of the system.
  5. Cement grinding
Cement grinding is not only the last process in the cement manufacturing process but also the most power consumption process.Its main function is to grind cement clinker(gelling agent, performance tuning materials) to appropriate particle size(fineness, superficial area),form a certain particle size distribution,increase the hydration area and accelerate the hydration rate to meet the requirements of cement slurry condensation and sclerosis.
  6. Cement packing