Study On The Effect Of Slow Cooling Time On Copper Flotation And Its Mechanism For Copper Flash Smelting Furnace Slag Of Zijin Copper

With the continuous exploitation of mineral resources,mineral reserves are declining,but China's demand for metal mineral resources is still strong.In copper smelting process,the production of It copper leaves with about 2-3t copper slag which contains large amounts of copper.Beneficiation recoveryof copper in such slag is technologically and economically feasible,due to the lower energy consumption when comparing with pyrometallurgical method.Zijin Copper.with an annual copper selmting capacity of 20 million tons produces 2000 tons of slag of copper content atabout 2%?6%,on this basis,study of the recycling of copper in the slag,has important economic and social significance in terms of the comprehensive utilization of mineral resources.The process applried by the smelter to the recovery of copper is a combination of slag ladle slow cooling and flotation process.For slag slow cooling technolagy,the total time for slow cooling and water coolingis called cooling cycle which plays a decisive role on the number of packages.Since slag packages are expensive and requires high maintenance costs,so it has important practical significance to determine the idealest slag cooling time.This paper takes Zijin Copper copper smelting slag as the research object,properties of furnace slag under different slow cooling time(6h,8h,10h,12h),their properties after comminution and their flotation characteristics are comparatively analyzed;floatability of different sections of slag(internal,center and external)is tested,and mechanism of cooling time's influence on their performance is detected through methods like electron microscopy scanning analysis,hydraulic analysis and so on.Specific results are as follows:Minerals in slag are complex,which are mainly composed of copper sulphide accounting for 83.33%of total copper,followed by native copper of 13.94%and copper oxide of 0.70%.The flotation results of flash furnace slag under different cooling time showed that with the increase of slow cooling time,copper recovery and grade tended to increase.When the cooling time was over 10h,the recovery rate tended to increase slowly,only 0.13%.Thus,the idealest slow cooling timefor Zijin Copper Flash Smelting Furnace Slag package should be10h.The flotation test results of furnace slag from different regions showed highest recovery rate of copper in the interior section followed bythe middle section and external section is relatively low,which supported the point that the longer slow cooling time is the better the flotation indexes can be obtained.The discrepancy in flotation index of flash furnace slag under different cooling time,lies in copper disseminating in the flash smelting furnace in various phases,so with the increase of slow cooling time,it increases the existence of coarser copper grain while that of fine disseminated copper particle is reduced.Under the same grinding fineness,the fine copper particles embedded in the slag can not be effectively liberated,thus affecting the flotation index.At the same time,due to the content high of fine particles,the flotation is easier to be coated which hampers selectivity of minerals,so that the useful minerals and gangue can not be effectively separated.