News Date:2015-11-09
Grinding system power consumption is an important criterion to judge the level of the merits of the grinding system. Currently, the grinding technology is to completely free ball (vertical mill or roller press finish grinding), large-scale development of the orientation of the device, along with advances in cement technology, changes in the trend in cement production integrated power consumption as follows: cement mill era> 100 kWh / t; part of the bed of grinding age 90 kWh / t or so, no ball age <80 kWh / t.
So how to reduce power consumption cement mill system do?
1. Reduce the cement mill system power consumption from the material particle size, moisture content, grindability, etc.
(1) the material is likely to affect the grindability of the grinding system power consumption.
Production of cement grinding system level, by the impact of clinker grindability, grinding power consumption quite different. Clinker and clinker grindability content of each mineral composition of clinker cooling rate, and when the mineral composition of clinker C3S content, less C4AF content, clinker cooling speed, fine crystal clinker vitreous, brittle texture, the grindability is good; if C2S clinker mineral composition and C4AF content, large clinker toughness, wear resistance coefficient, the clinker grinding hard, power consumption is relatively high. In addition, the clinker grindability also with the firing atmosphere, firing temperature, heating rate and other related materials such as burnt or yellow heart grindability material is relatively poor.
(2) the impact of material particle size.
Due to cement grinding mill when the material power utilization generally only 3% to 5%, thereby reducing the size of materials into the mill, grinding power consumption can be reduced. Practice shows that the average particle size of the material into the mill from 30 mm down to 2 mm ~ 3 mm, the mill output can be increased by more than 50%. As we all know, when the mill output increased dramatically, which corresponds to the power consumption will be significantly reduced. Domestic and foreign technical staff after years of intensive research and production practice, the proposed "more broken and less grinding to break instead of grinding" pre-crushing process, making the substantial increase in production mill, grinding lower power consumption, increase energy-saving effect . In addition, to reduce the over-grinding phenomenon, when added to the powdered material inside the mill, such as the use of fly ash as a cement grinding admixture should be advanced powder selected by the separator after sorting into powder as a finished product library, grits into the grinding mill, cement ball mill grinding efficiency can be increased 18 rate and reduce power consumption.
(3) material temperature and moisture on grinding system power consumption.
When the grinding material temperature exceeds 80 ℃, due to the impact of the role of the ball, most of the mechanical energy is converted into heat, the mill temperature can exceed 120 ℃, the high temperature is likely to cause material within the grinding particles generated electrostatic adsorption, the formation of fine particles The backing layer, the impact of grinding and polishing from the buffer, the grinding efficiency is lowered, power consumption increased cement ball mill output will be reduced by 10% to 15%. When the internal temperature of cement mill grinding up to 120 ℃, it can cause dehydration of gypsum to produce semi-hydrated gypsum, anhydrite or become completely dehydrated, quick-setting cement or false cause coagulation, affecting the quality of cement. In addition, the mill temperature is high, it will result in the mill cylinder bearings and other components and temperature, lubrication reduce the long-term impact the safe operation of the equipment, and even some companies appear to stop grinding cooling phenomenon, not only affect production, and Stop frequently to reduce wear and power consumption caused by rising production to Taiwan's. Therefore, under normal production conditions to minimize the grinding clinker temperature.
At the same time into the grinding material moisture must be strictly controlled, when the material moisture fluctuations (1% to 5%), the mill output fluctuations, will seriously affect the normal production run of the mill. Therefore, the average moisture material into the mill should be controlled at 1.0% to 1.5% is appropriate.
2. By adjusting the ball mill ventilation to achieve lower electrical energy consumption
Strengthen the mill ventilation, can reduce the mill buffer phenomenon, will help speed up the mill material flow, reduce the temperature inside the mill, can play a role to improve the mill output, cement mill wind speed should be controlled at 0.9 to 1.1 the range of m / s, the wind speed is too low if the mill, powder can not be the ground, resulting in over-grinding phenomenon, it will greatly reduce the grinding efficiency. Therefore, the need to strengthen the precipitator maintenance and management, improve ventilation area, reducing ventilation resistance, one can make a reasonable ventilation inside the mill, lower grinding power consumption, on the other hand can reduce the electrical energy consumption for ventilation. But also should pay attention to all parts of the grinding system sealed management, strengthen the routine maintenance and inspection, reducing system leakage. Mill system ventilation and air leakage will directly affect the mill grinding efficiency, but also result in increased power auxiliary equipment, allowing the mill to reduce production and increase power consumption.
3.through the cement mill regular maintenance and repair to reduce energy consumption
To ensure that the mill is running in good condition, you must carry out regular inspections and maintenance mill, periodic determination of terms for ball mill grading, fill rate, loading, the powder efficiency, cyclic loading rate, sieving curves, etc. refinement management, to maintain stable high-yield low-power operation of the mill system. Health mill is reasonable or not directly affect the mill's production, quality and grinding media consumption. A reasonable grinding grading is relative, temporary, optimum grading scheme, according to the specific circumstances, through long-term production practice, ongoing statistical analysis to measure and summarize, so as to achieve optimal fit native state .
4. by controlling the optimum particle size distribution and cement quality is the goal to achieve lower power consumption
(1) Effect of cement particle gradation performance at home and abroad have long-term analysis and research, and made basic conclusion, it is for high-grade Portland cement: Cement particle size distribution for optimal performance of 3μm ~ 32μm the total amount required for this grading particles> 65%,
(2) separate grinding advantage. When using poor grindability of raw materials such as slag cement grinding admixtures, although after slag cement grinding improve particle size distribution, bulk density increase of the original cement particles to increase the strength of cement mortar and concrete, compactness and durability, speed up the process of cement hydration early, cement mortar has good mobility. However, if the slag cement production and clinker grinding mix, clinker and slag due grindability of differences, slag particle mixing after grinding will be thicker than the clinker particle size, specific surface area when cement reaches 350 m2 / kg, the specific surface area of the slag is only 230 ~ 280 m2 / kg. If the slag activity into full play, to achieve the desired fineness (specific surface area should reach 400 ~ 450 m2 / kg), would cause too clinker grinding phenomenon, a lot of clinker fine particles within a very short period of time the water , resulting in an increase early heat of hydration and water demand increases, superplasticizer compatibility reduces the generation of a series of drawbacks, the use of performance deteriorated cement mill output reduced, power consumption increases.
Therefore, use separate grinding slag way, the production of high fineness, high specific surface area of the ore, then clinker and gypsum powder has been incorporated by formulated into a cement mixer to form a "separate grinding" process, and cement compared with ball mill grinding mill can significantly improve the station when production is conducive to the mill efficiency and increase the amount of admixture admixture, give full play to cement activity, avoiding over-grinding phenomenon, reduced grinding power consumption and production costs.
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