Expand the application of ultrafine grinding in the mineral industry

[xuanxuan geng]

The biggest challenge of fine grinding and Ultrafine mill of minerals is to obtain the desired size of the grinding product at lower energy costs and high grinding throughput. In this paper, the fine-ground and ultra-fine ground grinding products P80 have a particle size of 20 μm and 7 μm, respectively. During the grinding process, the electrical energy required for the dissociation of the ore particles is about 70% of the total cost of the beneficiation plant. When the conventional ball mill is used to grind the ore to below 20 μm, the grinding cost increases exponentially as the fineness of the grinding becomes thinner. Fine grinding and ultra-fine grinding (grinding size 200-400 mesh) and ultra-fine grinding (grinding size below 400 mesh) appeared after the 1970s, and the industry needs to solve the calculation of power consumption under fine grinding and ultra-fine grinding. problem. Under fine grinding and ultra-fine grinding, due to the increased mechanical strength of the fine-grained ore, the ore becomes difficult to grind, and the process control of fine grinding and ultra-fine grinding is poor, and the energy conversion efficiency is low, so fine grinding and ultra-fine grinding The power consumption increases dramatically. According to the current research depth of power consumption theory, there are three main applications: (1) Calculate the power consumption of the mill. Among several power consumption studies, only Bond's power consumption can be used to directly calculate the grinding power consumption. Because Bond's power consumption is the original, the feed size and product size can be determined by screening. Bond performance index can be measured according to the method specified by Bond, so the power consumption required for grinding can be directly calculated. (2) The work index of the known ore is known, and the work index of the ore to be tested can be determined by a grinding test. Under the same conditions, the same weight of the standard ore and the ore to be tested were separately ground by the same mill, and found from the sieve analysis curves of their ore and product. The work of grinding the same ore of the same quality under the same conditions using the same mill should be equal. (3) Use the area theory to estimate the power consumption at different crush ratios. In the same mill type, as the grinding time is extended, the crushing ratio is increased and the power consumption is increased. The new three-ring micro-powder grinding machine developed by our company mainly consists of hammer crusher, bucket elevator, storage bin, frequency conversion feeder, main machine, classifier, cyclone powder collector and pulse bag dust collector. , high pressure fan, air compressor, muffler, soundproof room, pipeline, power control cabinet and so on. The most important is the innovative flow field structure of the new three-ring Ultrafine mill, which improves the classification accuracy and produces the ultra-fine powder with D97 less than 2500 mesh. Wide range of fineness adjustment: It can produce various fineness products from 325 mesh to 2500 mesh, not only for the production of ultrafine powder, but also for the production of coarse powder size products instead of Raymond mill. In order to expand the application range of ultrafine grinding in the mineral industry, further research is very important. One of the gimmicks is to obtain a grinding product with a particle size of less than 5 μm at a higher processing rate, and to dissociate very finely-packed minerals. Pretreatment before hydrometallurgy requires the grinding of the ore to a fine grinding, which can be done using ultrafine grinding.