Comprehensive Recovery Of Valuable Metals From Nickel Smelting Slag By Mineral Processing And Metallurgy Technology

Nickel smelting slag is a solid waste produced during the production of nickel by pyrometallurgy.The slag contains valuable metals including nickel and copper.Failure to recycle these metals wastes resources,and disposal of nickel slag in stockpiles results in environmental pollution.Therefore,it’s of great significance to recover valuable metals from nickel slag.In this paper,nickel top blowing slag and nickel settling slag from a smelter in China are studied.Based on the analysis of process mineralogy characteristics of smelting slag,the experimental research on recovery of copper and nickel from nickel smelting slag by mineral processing and metallurgy method is carried out.In order to provide reference for the practical production of nickel smelting enterprises and the resource utilization of this kind of metallurgical waste residue.The main conclusions are as follows:(1)The process mineralogy of nickel smelting slag shows that there are many kinds of minerals in the slag,the distribution relationship is complex,and the copper-nickel mineral particle size is small.The contents of nickel in top blowing slag and settling slag are 1.81% and0.88% respectively,the contents of copper are 0.69% and 0.31%respectively.Theoretically,the proportion of nickel easy flotation(metal phase and sulfide phase)in top blowing slag and settling slag is 66.01%and 70.23% respectively,the proportion of copper easy flotation is 79.10%and 79.66% respectively.(2)Experimental study on direct flotation recovery of copper and nickel from nickel smelting slag shows that a copper-nickel mixed concentrate with nickel grade of 11.32% and nickel recovery of 64.02%and copper grade of 5.65% and copper recovery of 79.30% can be recovered from the top blowing slag by using the closed flotation process of one roughing,one cleaning and three scavenging.For settling slag,copper-nickel mixed concentrate with nickel grade of 5.21% and nickel recovery of 24.61% and copper grade of 2.85% and copper recovery of38.77% can be recovered.(3)Thermodynamic analysis shows that the chemical phases of copper and nickel in nickel smelting slag are transformed into metal phase and sulfide phase which are easy to flotation after reduction and sulfurization modification.Under the optimal modification conditions,the proportion of nickel easy flotation(metal phase and sulfide phase)in modified top blowing slag and modified settling slag is 98.76% and 96.97%respectively,the proportion of copper easy flotation is 97.23% and 91.36%respectively.Compared with the chemical phases of raw slag,the proportion of easy flotation in the modified slag has obviously improved.(4)The results of flotation recovery of copper and nickel from nickel modified slag show that a copper-nickel mixed concentrate with nickel grade of 8.86% and nickel recovery of 84.41%,copper grade of 3.58%and copper recovery of 89.51% can be recovered from the modified top blowing slag by flotation closed-circuit test.A copper-nickel mixed concentrate with nickel grade of 5.55% and nickel recovery of 66.16%,copper grade of 2.18% and copper recovery of 80.00% can be recovered from the modified settling slag by flotation closed-circuit test.Compared with the direct flotation recovery of raw slag,the recovery effect has obviously improved.Figures 27,tables 40,and references 114...