Research And Application Of The Win-win Point Of Grinding Efficiency And Classification Efficiency

The invention patent "a method to improve the efficiency of grinding and classification"(Patent No.ZL201210504854.4)was authorized in October 2015.And it was applied in October 2012 by Yunnan Phosphate Group Co.,Ltd.It Include a method to improve the grinding-classification efficiency by rough grinding and rough classification and the invention of win-win theory of 50 increasing fineness in overflow(fineness difference between overflow and grinding product).The method has applied in the 2million tons / year plants named Haikou and Anning which belong to Yunnan Phosphate Group Co.,Ltd.and got remarkable technical and economic effects."A method to improve the efficiency of grinding and classification" put forward a new theory of rough grinding and rough classification firstly.It studied the relationship between the grinding system and hydrocyclone classification system and get the result that win-win relationship rather than the relationship between subject and object.The fine grinding and fine classification process is adjusted to rough grinding and rough classification process based on the 50 increasing fineness difference in overflow by study the relationship between grinding and classification processing.The adjustment resulted higher grinding efficiency and higher classification efficiency,and also the system could provide high quality pulp which has more reasonable particle size distribution for the subsequent flotation operation.Through the adjustment,the plants improved the flotation concentrate yield,recovery rate and reduced the tailing grade.For more than 60 years,the grinding and classification theory is based on the fine grinding mineral processing that the mill is as the main body,the classifier as object machine in the system.In this system the grinding processing capacity is difficult to improve,grinding energy consumption is high and easy to overground.Taking Haikou Flotation Plant as an example,in the old system cyclone the grinding capacity is 131.97t/h,grinding fineness is-200 mesh 64.79%,overflow fineness-200 mesh 88.25%,increasing fineness in overflow is 23.45%,the energy consumption is 17.25 kW · h/t ore,the classification efficiency is 33.71%.In the new system,the technical indicators of rough grinding and rough classification are as follows,the capacity is 159.18 t/h,grinding fineness is-200 mesh 29.38%,overflow fineness is-200 mesh 81.28%,increasing fineness is 51.90%,fine particles in underflow is-200 mesh 12.89%,grinding energy consumption is 12.64 kW · h/t ore,classification efficiency is 60.33%.The processing capacity and technical index of coarse grading and non-equal descending cyclone grading method are significantly higher than the fine grinding system,the capacity increased20.6%,the energy consumption reduced 26.7%,the sand in overflow and over ground reduced.Fine grinding sub-annual output value of 567.4 million yuan,coarse roughing the annual output value of 736.6 million yuan,significantly improved economic efficiency.