| Jiama superlarge polymetallic deposit in Tibet is a representative deposit of copper polymetallic ore in China.The resources of Cu?Pb?Zn and Mo are abundant,but the metal minerals are always closely associated with each other,therefore it is difficult to get qualified single concentrate,and the exploitation and utilization of resources are severely restricted.It is extremely urgent to exploit and utilize this kind of mineral resources as the reduction of high grade manageable ore.On the other hand,flotation separation indexes depend largely on the grinding characteristics of ore, therefore the research on the grinding characteristics of ore has great significance for the comprehensive recycling and utilization of this kind of resources.In this paper grinding characteristics of Jiama polymetallic ore were researched mainly from the particle size composition and metals distribution,the selective grinding and the particle morphology of grinding products produced by ball mill and tower mill,and the influnce of grinding characteristics on flotation separation were explored.Through comparative analysis on particle size characteristics of ball mill products and tower mill products,it was found that tower mill products contained more intermediate fraction,the fine fraction and coarse fraction were less than those of ball mill products,overall the particle size distribution of tower mill products was relatively centralized.The analysis results of metals distribution of grinding products showed that the distribution ratio of Cu?Pb?Zn and Mo at appropriate size fraction in tower mill products was higher than that of ball mill products.Tower mill products had advantages over ball mill products for flotation separation of polymetallic ore.The relative change value of oversize cumulative yield before and after grinding?r and the relative change value of oversize cumulative metal quantity before and after grinding ?M were used to represent the selective grinding and analysis the laws of ore grinding.The results showed that Cu?Pb?Zn and Mo minerals all got selective grinding.Among of the metal minerals the grinding rate of Pb minerals was the highest,and the grinding laws of Cu minerals and Zn minerals were relatively consistent.By the comparison of grinding laws of ore under different grinding process,the grinding rate of coarse grained metal minerals in ball mill is lower than that of tower mill,the grinding rate of fine grained metal minerals in ball mill is higher than that of tower mill.The grinding differences of Mo minerals were most obvious.The results of study on effects of grinding characteristics on flotation separation showed that the best grinding fineness of both ball mill and tower mill for flotation separation was 70%-0.074mm.Under the best grinding fineness,the recovery of Cu and Mo of tower mill-flotation concentrate increased 1.70%and 6.22%respectively compared with that of ball mill-flotation concentrate,so tower mill was more beneficial to the flotation of Cu and Mo.The grinding technology efficiency of valuable minerals was used to analysis and assess grinding effects.The results showed that the grinding technology efficiency of Cu?Pb?Zn and Mo minerals when using tower mill was higher than that when using ball mill.Among them the difference of grinding technology efficiency of Mo minerals was most obvious.When the grinding fineness was 70%-0.074mm,the grinding technology efficiency of Mo minerals of tower mill product was 53.17%,which increased by 12.89%compared with 40.28%of ball mill product.It showed that tower mill had obvious advantages over ball mill when grinding Mo minerals. |
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