In the production process of cement, the grinding process of raw materials in the raw material mill is a complicated process which is influenced by many factors, such as the structure of the grinding mill, technical process, the grading of the vertical roller mill and the features of the materials. The main material for producing raw materials is limestone which is often stored in the open air, for this reason, the production of raw materials is easily influenced by the weather.
The temperature in winter is low, so is the temperature of the feeding raw materials, which will produce big temperature difference with the temperature inside the grinding mill. When the water content of the raw materials is high and the temperature inside the grinding mill is also high, the water inside the raw materials will be heated and become vapor, so that the fine powders will stick onto the grinding media and the lining board to form the crash pad layer or block the grating hole of the partition board, which will hinder the circulation of the materials and reduce the powder grinding efficiency. The common solution to this problem is stopping the feeding and smashing the cabin, which will reduce the yield of each mill per hour and at the same time, increase the consumption of balls and electricity.
As the raw materials has high humidity and high water content, the moving speed inside the spiral conveyor will be slow, which will decrease the conveyance ability of spiral conveyor. In addition, due to the high water content and low temperature of the raw materials, the humidity of the waste gas is also high, and the waste gas will easily condense inside the pipes, which will cause blockage of the pipe, so that the grinding mill should regularly stopped to handle the blockage, thus reducing the running rate of the grinding mill.
After the profound research and discussion of the engineers and technicians of Henan Mining Machinery Co., Ltd., we finally figure out the best way to solve this problem: add a hot blast heater in front of the raw material mill, and in the actual operation, the temperature of the in-fed hot air may reach 389鈩? so that the full grinding problem caused by the high humidity of the raw materials can be solved. The machine-hour yield can be improved by 3 tons than the same period of last year. The temperature of the discharging waste air can reach 90鈩?and temperature of the waste air that is emitted to the air is higher than 54鈩? thus eliminating the condensation. Due to the addition of the hot blast heater, the grinding mill can not only grind the materials, but dry them and the running rate of the spiral conveyor is also improved.