Novel Approach For Recovery Of Scattered And Precious Metals From Copper-rich Solution Of Copper Anode Slime

Copper anode slime is an important resource for extracting the scattered and precious metals with high value.In the process of copper removal by pretreatment of copper anode slime,the scattered and precious metals of Au,Ag,Pt,Pd and Te are dispersed into copper-rich solution to varying degrees.However,there is no yet recovery process targeted at the scattered and precious metals in copper-rich solution with high acidity and copper content,leading to the loss of a large number of the scattered and precious metals in copper smelting industry.For the industry's problem,it is urgent to develop a novel technology for high efficiency recovery of the scattered and precious metals from copper-rich solution.The?-p H diagram of Te-H₂O system and distribution graphs of Te(IV),As(V)and As(III)were drawn by thermodynamic calculation.Combination with the actual potentials of coexisting ions,its reduction regular pattern was revealed,and the thermodynamic feasibility of in-situ reduction was demonstrated.A novel process for in-situ precipitation of the scattered and precious metals by activated sponge copper prepared by iron powder reduction was established.Under the optimal conditions,85.02%Te was precipitated.The total contents of precious metals in concentrate are211.0 g/t.According to the?-p H diagram of As-Fe-H₂O system,based on Fe As O₄precipitation to regulate and control[Fe³⁺]/[Fe²⁺]in solution,a novel process of in-situ adjusting the potential of copper-rich solution by Fe²⁺was developed combined with tellurium trapping principle.Efficient separation of Te and the synergistic capture of precious metals were realized.Under the optimal conditions,the precipitate efficiency of precious metals and Te were about 100%and 36.1%,respectively.The grades of Te,Au,Ag,Pt and Pd in concentrate are 18.24%,124 g/t,10.54%,1010 g/t and 320 g/t.The process mineralogy of platinum and palladium concentrate was analyzed.The leaching behavior of impurities was discussed by drawing the speciation diagrams of Bi(III)and Fe(III)chlorocomplexes.A novel process for impurities removal and enriching precious metals by acidic chlorination leaching was established.Under the optimal conditions obtained by orthogonal experiment,the leaching efficiency of Te,Bi,Fe and As were respectively 94.34%,99.25%,91.16%and70.75%.The grade of precious metals is 5.54 enricher than that before leaching.For the recovery of Te and Ag from chloridized acid leaching solution of concentrate,the species distribution of Te(IV)and Ag(I)chlorocomplexes in acid leaching solution were analyzed,and the actual potentials of coexisting ions were calculated theoretically,which proved that the process of efficiently recovering Te and Ag by Na₂S₂O₅reduction was feasible in thermodynamics.The electrochemical behavior of Te(IV)on platinum electrode in HCl-H₂O system was studied by cyclic voltammetry.The results shows that the reduction process of Te(IV)is a quasi-reversible process controlled by the diffusion step.Under the optimal conditions,97.51%Te and 80.32%Ag were recycled.The content of crude tellurium is 94.19%with 0.578%Ag.In this paper,an effective method for comprehensive recovery the scattered and precious metals from copper-rich solution and simultaneously purifying and As removal is developed,which is beneficial to perfect the separation and enrichment process of the scattered and precious metals from sulfuric acid system.Precious metals in concentrate were enriched by hydrometallurgy.The proposed process has certain theoretical guidance and reference significance for the treatment of similar precious metal raw materials.