| Fluorite minerals are abundant in China. The ranking of production and export levels is the first in the world. Compared with other minerals, fluorite ores are very fragile in grinding process because of its role of selective grinding and crushing phenomenon. As a result,it is not good for the subsequent processing. Therefore, it is good for improving the technical and economic indicators of fluorite ore plant to improve grinding effect of fluorite ore.In this thesis, the fluorite mineral in Chongqing is made to be as a research object. The ore is typical of moderate weathering. The ore mineral mainly consist of fluorite and barite whose grade are 45.71% and 32.83% respectively. The main compoents in the gangue mineral is quartz whose content is 18.37%. Screen analysis results of the ore shows that the mine disintegrate degrees can reach 84.34% in-0.15+0.074mm. From the destruction-resistant mechanics properties tested, we can find that the hardness of the fluorite is low, the brittleness is large. The ore is easily fragile in grinding. In the existing section of the plant, there is a great influence of grinding products about the indictors of follow-up to flotation operation.In this paper, we carried out the rod mill and ball mill test, accurate ball-load scheme test, section medium test and grinding condition test based on the grinding of the plant existing processes. The product particle size of the rod mill is symmetrical because of its shape. It can satisfy the follow-up of flotation operation requirement. The ball mill test, accurate ball-load scheme test and section medium test results show that the quality of grinding product is poor with conventional grinding conditions. The yield of rough grade and fine grade is too large and the yield of qualified grade is too low. It is fail to follow-up to flotation operation granularity requirements.The grinding condition test was based on the existing ball mill equipment difficult to transform as the prerequisite in plant. The trial that carried out ball size, the ball ratio and the best ball ratio test is crushing statistic mechanics principle as the guiding ideology and broken events quantity as judge. Finally, the weight of ore and ball test was grinding efficiency as judge which is effective broken. The two groups of best grinding conditions scheme are as follows:The first scheme of grinding condition is that ore weight is 32kg, ball weight is 90kg, the ratio of ore weight and ball weight is 3:1, grinding time is 6min,filling percentage is 40% and ball ratio is(?)70:(?)60:050:045:030=20:25:20:20:15.The second scheme of grinding condition is that ore weight is 24kg, ball weight is 80kg, the ratio of ore weight and ball weight is 3:1, grinding time is 6min,filling percentage is 35% and ball ratio is(?)70:060:(?)50:(?)40:030=20:15:25:15:25.The flotation indexes were better than the actual index of the plant by flotation flow test in laboratory.Experimental studies have shown that:for easy fragile ores, the broken way of spherical media is point-contact, breaking force in contact point is too large, the role of crushing force less accuracy and therefore it had crushed the phenomenon of seriously. the broken way of rod and forging shape break is line-shaped contact, so the product particle size is symmetrical.However, by ball mill, this research ascertained the proper of grinding condition,and reached a good grinding effect in this experiment. It provided a good idea of grind for easy fragile and non-metallic minerals. |
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