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The technics of Cement production process

Author:news center Post Date:2009-8-14

In the technics of Cement production process, People usually choose limestones and clays as the main raw materials, crushing, concocting, grinding them into cement raw meal, feeding them into cement kiln. After being calcined maturity, adding appropriate amount of gypsum (sometimes mixing the mixed material or admixture) then being grinded, and the cements form.

1, crushing and pre-homogenization
In the first phase of cement production, most of the materials should be crushed, such as limestones, clays, iron ores, coals etc. Especially the limestones are the largest demand materials. Its raw size from mining is very large and is with high hardness. Therefore the limestone crushing is very important in the cement production.
In the phase, the needed equipments are primary crusher and secondary crusher. Here the recommended machines are jaw crusher, impact crusher, cone crusher. Sometimes the construction wastes are used as the raw materials, and then a mobile crusher is also a wise choice.
The pre-homogenization process makes the materials storage and homogenization.

2, The prepare and homogenization of cement raw meals
In the cement production process, every production of 1 ton of Portland cement grinding at least needs 3 tons of materials (including raw materials, fuel, clinker, mixed materials, gypsum). According to statistics, the grinding process in thedry-process cement production lines operating cost 60% power, in which grinding raw materials accounted for more than 30%, grinding coal accounted for about 3%, and about 40% of cement grinding. Therefore, a reasonable choice of grinding equipment and processes and to optimize the process parameters, the correct operation, the control of operating system, is of is of great significance to ensure product quality and reduce energy consumption.

The available grinding mills include Raymond mill and other roller mill. But usually the processing capacity of the Raymond mill can't meet the big demand of the clients. We know the amount of the rollers determines the processing capacity of grinding mills, and at present the most rollers of a Raymond mill are 4 so its capacity can be at most 4 ton per hour. So a new roller mill with 6 rollers has been the popular one and achieves high repute from the users, which is named Super Pressure Trapezium Mill. It is the real king of roller mills and its capacity can be up to 20 tons per hour base on limestones materials. Also, another new one is called High Pressure Suspension mill, whose capacity can be about 10 tons per hour.

3, pre-decomposition and the burning of cement clinker
Preheating the raw material and some decomposition are completed by the preheater, instead of some functions of rotary kiln to shorten the length back to the kiln.
Raw material completes the preheating and pre-decomposition in the cyclone preheater. The next process is carried out the rotary kiln and calcined to cement clinkers.

4, cement grinding
Cement grinding is the final process in cement manufacturing, which cost the most electric power. Its main function is to grind cement clinkers into condign sizes (in fineness, specific surface area etc.) and make them form a certain particle size levels to meet the coagulation, hardening requirements.

Vertical mill is the main equipment in cement grinding. LM series vertical mill are with high grinding efficiency and with good operation stability.To some extent, they reduce the power consumption or increase the system output. Also in the process technics, compared with the closed-circuit grinding, opened-circuit grinding process is only more saving invest, and more facilitated in the maintenance and management. However, the adjustment of closed-circuit grinding is much more convenient and more adaptable to the quality changes and moisture of raw materials. Because the grindability of the clinkers from different clinkers suppliers are very different. To this point the capacity and final fineness of the closed-circuit grinding mill production are not changed much even if raw materials are from different places. Therefore, it has more advantages than opened-circuit grinding. Some experts on recommending opened-circuit grinding believe that the particle size distributions in the open-circuit cement grinding process are wider, thus the consistency standards demand less water. So the opened-circuit grinding is welcomed in concrete mixing station. To choose which one, the cement factory should be based on the actual situation of their choice. But LM series vertical mill apply to both.

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