To reduce the noise intensity of the ball mill, protect the health of workers and surrounding people, improve work efficiency and reduce production costs, Shandong Zhaojin Concentrator has transformed two ball mills. After repeated tests, the rubber mill lining replaced by manganese steel lining has obtained the grinding related technical parameters, which meets the requirements and has been officially put into production. Based on the conventional monitoring data, the mill noise and economic benefits before and after KOSGA transformation are analyzed
Materials and Method
Noise measurement instruments and methods: ND2 precision sound level meter and octave filter made in China are used for testing, and the noise is tested according to the “ Noise Detection Standard on Industrial Enterprises”. For the ball mill workshop without sound insulation room, according to the location of the ball mill, the flow of workers and mechanical operation observation, respectively set up a monitoring point on the left and right of the workshop and in the middle of the two ball mills about two meters away from the noise source. A sound level is used to evaluate continuous steady-state noise.
Noise control method: rubber mill liner is produced according to ball mill shell structure and original manganese steel lining specification (1.4mx0.74m x 0.07m). After taking out the manganese steel lining in the main body of the ball mill, the rubber lining is installed in the shell body of the ball mill successively (front and back). Each ball mill is equipped with 48 pieces. First, press it with shell lifting rod, and then fix rubber lining on shell body of ball mill with screws to prevent rubber lining from falling during rotation.
Results
Noise monitoring: the noise intensity of ball milling workshop with manganese steel lining is 94 ~ 103dB (a), while that of ball milling workshop with rubber mill lining is 87 ~ 92 dB (a), and the noise reduction difference is 7 ~ 11 dB (a). Rubber mill lining performs better.
Liner loss: 2 ball mills use 28.12 tons of manganese steel lining every year and the service life is 12 months. According to the current price, the price of two sets of manganese steel lining plate is 164 thousand CNY. The price of rubber lining board with a weight of 2 tons is 198,000 CNY, and the service life is 24 months. Although the price of rubber lining plate is 34000 yuan higher than that of manganese steel lining plate, its service life is 24 months. In contrast, the use of rubber lining plate can save material cost of 130,000 CNY per year.
Energy saving: with rubber lining plate, 2 kwh of industrial power can be saved per ton of ore, and 180000 kwh of electricity can be saved in the whole year. According to the production power consumption of 0.5 yuan CNY, 90,000 CNY can be saved every year.
Ball wear: manganese steel liner wear 8.0 tons of steel ball every year, the price is 28,000 CNY. Rubber Village Board wear 2 tons of steel ball every year at the price of 7,000 CNY.
The monitoring results show that the rubber lining with better noise reduction improves the working conditions of workers and the environment of nearby residents and protects their health.With advantages of strong wear resistance, saving electric energy and reducing labor intensity, 241,000 CNY of production cost is saved for enterprises every year. It not only supports the economic effect, but also is a good measure for comprehensive noise prevention of ball mill.