| Parameters |
| During the process of cement production,it needs grinding three tons materials for product one tone portland cement (including all kinds of raw materials、fuels、clinkers、compound material、gypsum).According to the statistics,the cement dry process production line grinding operation needs to consume 60% power of the the whole plant, among it the raw material grinding occupy above 30%,the coal grinding occupy about 3%,the cement grinding occupy about 40%.Therefore, we should reasonable select grinding equipment and technological process,optimize technological parameters,proper operation,control work system. And this will have great significance on ensuring production quality and reduce energy consumption. | |
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| Method |
The main materials of cement production are limestone and clay,they turn into raw materials through crush、burdening、grinding by vertical mill,then turn into clinker by feeding into the cement rotary kiln, and then put in appropriate gypsum 、 some mixed materials or admixture, then turn into cement through roller press and cement mill. At last transport out of the plant after packaging by package equipment or bulk cement loaded.For different raw material preparation method,the production line can be divided into dry process and wet process.
Cement dry process cement production technological process: is the approach to dry raw material and grinding or dry raw material powder feed into the dry process rotary kiln.There is also an approach named semi- dry method,which needs put in appropriate water into the raw material powder to make into the raw material ball,and then feed in into the Lepol kiln,it is also belongs to one of the dry process.
The main advantages of dry process is low heat consumption,the heat consumption of dry process kiln with preheater is 3140-3768J/KG. The weakness is raw material ingredient not well-distributed, the workshop huge dust and high powder consumption.
Cement wet process cement production technological process: is the way to grinding the raw material and water into raw material thick liquid and then feed into the wet process rotary kiln. There is also an approach to dry the raw material thick liquid into the raw material chunk,then feed into the kiln,which named semi-wet process,also belongs to wet process.
The advantage of wet process is easy operation,easy control of raw material ingredient,high quantity of production,convenient convey of thick liquid,little dust of workshop etc. The weakness is huge heat consumption,usually the clinker heat consumption is 5234-6490J/KG. | |
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| Equipment |
| The main equipment of cement production line including: rotary kiln、cyclone preheater、cooling machine、Crusher, vertical mill, roller press, cement mill, coal mill, dryer, dust collector, packaging machines, bulk machines, conveyors, electrical control etc. | |
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| Technological |
Pre-homogenization:Crushing: during the process of cement production,most of the raw materials need to be crushed,such as lime stone、clay、iron ore、coal etc. Limestone is the largest amount raw material for cement production,the particle size is bigger and the hardness is higher, so the limestone crushing have an important position at the material crushing of cement plant.
Raw material pre-homogenization: the pre-homogenization technology is achieving the raw material initial homogenize by scientific stacker and reclaimer technology during the storage and reclaimer process of raw materials, to ensure the raw material ground has the capability of storage and homogenize.
raw materials homogenize:At the process of dry process cement production,stabilize the raw material ingredient is the premise of clinker sintering, raw material homogenize system is used for stabilize the raw material ingredient inlet the kiln.
preheat and decomposition:We use the preheater to finish the preheat and decomposition of cement raw materials, replace part of the capabilities of rotary kiln and reduce the length of rotary kiln. The materials finished gas exchanging heat process inside the rotary kiln under the state of suspend and preheat. The raw materials and fervor gas exhausted from rotary kiln were intensive mixing, enlarge the contact area of gas, heat transfer speed higher,heat exchange rate higher,production rate of rotary kiln higher,heat consumption of clinker sintering lower.
the material dispersion:80% of the raw materials feed into the preheater pipe will exchange heat at the entrance of the pipe. At the impact of the high speed updraft, materials turn up with air flow, meanwhile dispersed.
the right of gas-solid separation:When the airflow with material powder get into cyclone, and were forced to do rotate flowing at the annulus space between cyclone barrel and inside barrel while doing downward movement
the precalcining:Appears of precalciner technology is a technological leap of cement calcination process. It is added between the preheater and calciner kiln using kiln tail rise flue, set the fuel injected device, so that the process of carbonate endothermic exothermic decomposition of the fuel combustion process and raw materials, in the decomposition furnace to the suspended or fluidized state quickly, so that the decomposition rate of kiln feed is increased to 90%. The original task decomposition of carbonate in the rotary kiln, and moved to the decomposition furnace; fuel from the calciner to join the majority, joined by a small part of the kiln, reducing the heat load of the kiln firing zone, extending the liner material life, in favor of large-scale production; due to the mixing of fuel and raw materials, timely delivery of fuel combustion heat to the material, combustion, heat transfer and carbonate decomposition process can be optimized. So it has a series of excellent performance and features of high-quality, high efficiency, low power consumption.
sintering:After completion of the raw material in the cyclone preheater preheater and precalciner, the next process is carried out into the clinker kiln firing. The carbonate rapidly resolved and occur a series of solid-phase reaction in rotary kiln to bring the mineral into being.As the material temperature close, the liquid will become minerals dissolved in the liquid phase reaction and generates a large number (clinker). After the clinker burning, the temperature began to decrease. Finally, the cement clinker cooler unloading the kiln clinker cooler temperatures to the downstream transport, storage libraries and cement mill can withstand temperatures of hot clinker while recovering sensible heat, improving system thermal efficiency and clinker quality. | | |
