Complex Copper, Lead, Zinc, Silver And Metal Sulfide Concentrates Recycling

Great progress had been achieved in copper,lead,zinc metallurgical industries in China.Along with national economy developing,the consumption of nonferrous products is more and more.Chinese is primary country of product and consumption of copper,zinc and lead.So the following problems are arised,the consumption of the excellent resource is increasing,the resource gradually dries up,the development of nonferrous metals is controlled by resource,and the providing of nonferrous metals can't satisfy the development of national economy.All kinds of resources of nonferrous metals must be exploitate and utilize in order to keep continuable development of nonferrous metals.The three rivers ore area is the important resource area of nonferrous minerals in China.The characteristics of these minerals are that all kinds of nonferrous metals reciprocally accrete,floatation is ease but separation is difficult,the reciprocal holding of the metals in the obtained concentrate from dressing leads to the concentrates' quality is bad,and the recovery rate is low.The new metallurgical technique which is used to treat complex polymetallic concentrates must be exploitate in order to actualize high-performance and compositive exploitating and utilizing.The raw material is complex polymetallic sulfide concentrate containing copper, lead,zinc and silver.Compared with the traditional metallurgical processing,the new hydrometallurgical technology of treating this kind of concentrate was determined.The conditions experiments of every chief segment in the whole flowsheet have been systematically investigated in the laboratory,then the whole hydrometallurgical processing flowsheet which treated complex polymetallic sulfide concentrate containing copper,lead,zinc and silver was determined.And the theoretical analysis has also been carried out.The main contents are followed as:1.Pressure leaching.Based on the existing thermodynamic research,the pressure leaching thermodynamics of treating complex polymetallic sulfide concentrate was studied,and the potential—pH diagrams for the system of CuFeS₂-H₂O,ZnS-H₂O,PbS-H₂O,FeS₂-H₂O at 298K and 423K were drawn. Complex polymetallic sulfide concentrate was treated using pressure leaching in autoclave,the optimal leaching conditions are determined after reviewed the conditions of leaching temperature,time,the dosage of sulfuric acid,oxygen pressure,granularity of concentrate.Complex polymetallic concentrate 1: granularity of concentrate was -0.038mm(-400 screen mesh)≥96%,ratio between liquid and solid was 4:1,temperature was about 150℃,the oxygen pressure was 1.2～1.4MPa,leaching time was 180min,the beginning acid concentration was 145～155g/L,sodium lignosulfonates was proper amount,stirring speed was 850r/min.Under these conditions,the leaching rates of every metal were Zn-94% and Cu-97%.Complex polymetallic concentrate 2:granularity of concentrate was -0.033mm(-425 screen mesh)≥99%,ratio between liquid and solid was 4:1, temperature was about 150℃,the oxygen pressure was 1.2～1.4MPa,leaching time was 180min,the beginning acid concentration was 140～150g/L,sodium lignosulfonates was proper amount,stirring speed was 850r/min.Under these conditions,the leaching rates of every metal were Zn-95%and Cu-96%.2.Extracting copper from the liquid of pressure leaching.For the first time,the copper has been extracted from the leaching liquid which contains high concentration of copper,zinc and sulphric acid.Through the test of following conditions:loading copper ability of organic phase,extraction temperature,mixing time,phase ratio of extraction,phase ratio of stripping,acid concentration of stripping liquid,the suitable extraction processing was obtained that suitable conditions of extraction were phase ratio(O/A)4:1,the content of extractant in organic phase(V/V)25%,mixing time 3min,extraction series over11,extraction temperature 30-40℃;Under these conditions,the extraction rate of copper＞95%. The suitable conditions of stripping:phase ratio(O/A)1:1,the acid concentration of stripping＞250g/L,mixing time 2min,stripping series over 5,stripping temperature 30～40℃;under these conditions,the stripping rate of copper＞95%.3.Deprive the element sulphur in the slag of adding pressure leaching.The sulphur concentration was enriched through floatation from the leaching slag which contained high concentration of element sulphur,lead and silver.The suitable conditions of floatation were ore pulp concentration 10～20%,granularity of raw ore, 2# oil 10g/t,use the process of first stage rough dressing—two stage fine dressing—three stage scavenger.The sulphur content of floating sulphur concentration was＞60%,recovery rates of floating were sulphur＞70%,copper＞65%,zinc＞65%,lead～15%.Element sulphur was deprived from the enriched sulphur concentration using distillation,the conditions were temperature 460～480℃, volatilization rate of element sulphur＞98%,other metal element's loss＜0.5%.4,Carbonate conversion -silicofluoric acid leaching on flotating gangue.It was the first that treated the material which containing lead sulfate using carbonate conversion-silicofluoric acid leaching.Lead sulfate was converted using carbonate treating floatation gangue.After testing these conditions:the conversion time,the dosage of conversion agent,conversion temperature,the suitable conversion conditions were determined:temperature20-25℃,time 30 min(first time), 30min(second time),the dosage of ammonium acid carbonate is 0.9times of theoretical value,the mol ratio of ammonium acid carbonate and ammonia liquor is 1:1.conversion slag was leached using silicofluoric acid,after testing the elements of the beginning acid concentration,leaching time,leaching temperature,suitable leaching conditions were determined:leaching temperature～60℃,time 30 min, extricated silicofluoric acid concentration 125～150g/L.through the study of carbonate conversion-the experiment of silicofluoric acid leaching conditions,the last process of leaching lead was determined: conversion-leaching-conversion-leaching,the leaching rate of lead under these conditions is＞94%.5,Leaching silver using thiourea.Based on the existing study,thiourea leaching silver from floating tailing and the thermodynamics ware studied,then theφ—pH diagram of Ag₂S(Ag)-SCN₂H₄-H₂O at 298Kwas drawn.The mechanics and kinetics of Leaching silver using thiourea were studied,and the kinetics equations were set up.After testing the elements of thiourea concentration,Fe³⁺concentration,leaching time,temperature,the processing of leaching silver was determined:two-stage leaching,leaching temperature 60-70℃,thiourea concentration:first stage 55g/L, second stage 20g/L,the ratio of liquid and solid is(7.5-10):1,time 180min, Fe³⁺concentration～10g/L;the silver leaching rate under these conditions is＞93%.The following contributions have been made:(1)The whole hydrometallurgical flowsheet of synthetic recovery copper,lead, zinc,silver from complex polymetallic sulfide concentrate has been developed;.(2)Using pressure leaching to treat complex polymetallic sulfide concentrate containing copper,lead and zinc was studied,and the good leaching rates of copper and zinc was obtained.(3)Separation copper and zinc from the solution of high concentration of copper,zinc,sulfuric acid using extraction was studied,in which the concentration are Cu～40g/L,H₂SO₄～70g/L,Zn100g/L,according to the result of experiment study,many stage countercurrent extraction processing was determined.(4)The process of using carbonate conversion -silicofluoric acid leaching to treat the floating gangue which contain high concentration lead sulfate was studied, and suitable processing was determined:Two times conversion -leaching.(5)Kinetics process of leaching silver using thiourea was studied,kinetics equations on the elements of leaching temperature,thiourea concentration, Fe³⁺concentration were set.