Comprehensive Recovery Of Cu And Associated Au And Ag In Sulfur-oxygen Mixed Copper Ore

With the copper sulfide diminishing,depleting and being oxidized,mixed sulphide-oxide copper ore has became an imperative component of copper resources.Au and Ag are copper family elements,which are associated to copper ore for the most part in crust.So many large copper mines around the world are also very often large gold and silver mines.Now,with the development of science and technology economy,the demand for Cu,Au,and Ag keeps growing and growing,therefore,both the development and utilization of mixed sulphide-oxide copper ore and the reinforce of comprehensive recovery of Cu and associated elenments,Au and Ag,are particularly imperative.In view of this,based on the pure mineral test,the comprehensive recovery of Cu and associated elements,Au and Ag,in mixed sulphide-oxide copper ore was investigated.According to the pure mineral test results and the characteristics of the ore,.a targeted innovative solution,namely "using Na2SO3 + Na2S to conceal and eliminate secondary Cu2+,rationally controlling grinding fineness,combined dispersion and synergistic activation,low alkalinity flotation without lime,and mixed use of ester-collector" was proposed,and the further study of which was carried out,aiming at the realization of comprehensive recovery of Cu and associated elements,Au and Ag,and providing reference for the exploitation and utilization of similar mineral resources simultaneously.In addition,the inner causes for the effect of pH value,Cu2+ and Na2SO3 on mineral floatability was analyzed by measuring the adsorption capacity of pure mineral surface collector,which aims to reveal the activation and inhibition mechanism of Cu2+,Na2SO3 to pyrite from the perspective of the change of collector adsorption capacity.Firstly,two kinds of pure mineral tests were carried out:Single pure mineral test and Mixed pure mineral test.The flotation behavior of chalcopyrite and pyrite under using conventional collector(Ester-205,butyl xanthate Z-200 ammonium butyl aerofloat)and different pH conditions was studied in single mineral test.The effects of chalcopyrite(The dissociation of Cu2+),different inhibitors(Humic acid sodium,Na2SO3,Ca(ClO)2,KMnO4)on floatability of pyrite were investigated in a mixed experiment of pure minerals.The results show that the presence of Ester-205 + Z-200 in combination has a stimulative effect on the recovery of chalcopyrite in low alkalinity pulp environment.The floatability of pyrite can be enhanced with chalcopyrite(Cu2+),and the presence of Na2SO3 can weaken or even eliminate the activation of Cu2+ in a certain extent,and generates a strong inhibition to pyrite.In this paper,the characteristics of the actual ore was tested,and the influence of the characteristics of ore on the comprehensive recovery was also analysed.The results presente that this ore,with the Cu content of 1.78%,the occupancy of secondary copper sulphide of 18.54%and the Cu oxidation rate of 28.09%,belonges to a type of mixed sulphide-oxide copper ore,and it is necessary to preclude the disadvantage brought by secondary copper sulphide and lay great stress on activation and strengthening collection researches in integrated recycling process;The iron sulfide minerals are dominated by pyrite,how to prevent the pyrite from being collected simultaneously and realize the copper-sulfur separation would be an important difficulty for comprehensive recovery.Great amount of easily-mudding gangue minerals is embodied in ore,thus it is of great importance to control the grinding process rationally and enhance the dispersion of slime;The content of associated gold-silver is high,which mostly exists in electrum,and largely occurres in intergranular form and inclusion form,closely related with copper mineral.The occurrence of associated gold-silver makes it possible to be enriched and recovered in copper concentrate.Its particularity should be considered during the process of comprehensive recovery,and the collection research shoule be laid great stress on.Then,according to properties of the ore,on the basis of pure mineral tests,an innovative solution was proposed as "using Na2SO3 + Na2S to conceal and eliminate secondary Cu2+,rationally controlling grinding fineness,combined dispersion and synergistic activation,low alkalinity flotation without lime,and mixed use of Ester-collector",and effects of various factors of the solution were investigated.The results indicate that it is reasonable to adjust the grinding fineness to-74?m accounting for 80%;The optimal effect can be obtained when the Na2S dosage is of 1500g/t and the dosage ratio of(NH4)2SO4 to Na2S is of 1:1;It is advisable to choose the Ester-205 dosage as 100g/t and optimal dosage ration of Ester-205 to Z-200 as 1.25:1 under mixed using.Finally,under the optimum conditions,the comprehensive recovery of copper and associated gold-silver from the ore can be successful realized by adopting a process of sulphide and oxide bulk flotation consisting of two roughing,two cleanings and one scavenging.Under the optimum conditions,the copper recovery of concentrate can reach 91.19%,in which,the grade of Au and Ag can reach 20.02g/t and 1260.48g/t,with 90.74%and 83.71%recovery respectively.The change of adsorption capacity of chalcopyrite and pyrite surface collector(Ester-205+Z-200)was determined by UV-visible spectrophotometer,by which the effects of pH,Cu2+ and Na2SO3 on the flotation behavior of chalcopyrite and pyrite was investigated.It is shown that the adsorption capacity of chalcopyrite surface collector is much higher than that of pyrite in low alkalinity condition.The presence of CuSO4 increases the adsorption capacity of pyrite surface to Ester-205 and Z-200;The use of Na2SO3 can reduce or even eliminate the activation of Cu2+,and plays a role in inhibiting pyrite.