Study On The Electrochemistry Mechanism Of Flotation Separating Copper-lead Sulphide Minerals

For their similar flotability, copper-lead minerals are generally collected as mixed-concentrate, then the extra collector on the mixed-concentrate will be removed, after that the separation experiment will be carried out. The separation process is the difficulty, poisonous reagents usually is used in the separation experiment. To solve such a problem, this study employed a nontoxic-combination reagent as depressor, O-isobutyl-N-(ethoxycarbonyl) thionocarbamate (IPETC) as collector for the separation experiment, the extra collctor butyl xanthate was removed by sodium sulfide first. In this paper Eh-PH diagram and cyclic voltammetry were adopted to study the mechanism of chalcopytite and galena reacting with different resgents.The flotation test showed that butyl xanthate had good catching ability for both chalcopyrite and galena, IPETC could be the collector for separation test as its good selectivity for chalcopyrite. The recovery of chalcopyrite and galena were both low after collector-removal test. The separation test which employed sodium sulfite, sodium silicate, CMC and YZJ(combianate depressor contains sodium sulfite, sodium silicate and CMC) independently as depressor were carried out, the result showed that the single depressor all had good selectivity inhibition to chalcopytite and galena, and the combined-depressor was more effective than single depressor.The adsorption test showed that the adsorption of butyl xanthate on chalcopyrite and galena was gradually decreased with the increasing of sodium sulfide used. IPETC adsorbed amount on the surface of chalcopyrite and galena decreased when adding depressor like sodium sulfite, sodium silicate, CMC and YZJ.The flotation experiments of manually mixed ore of chalcopyrite and galena showed that when use YZJ as depressor, the best separating target would be obtained.The result of cyclic voltammetry test showed, butyl xanthate adsorbed on chalcopyrite was in the form of xanthate copper, on galena was xanthate lead. Anodic peak generated by minerals and xanthate was disappeared in the sodium sulfide and butyl xanthate mixed solution,this was agree with the result of adsorption test.The result of Eh-pH diagram and cyclic voltammetry test showed that the sodium sulfite would react with galena and produce lead sulfate which is the reason of sodium sulfite could be a depressor for galena, in the case of sodium silicate the reaction product was lead orthosilicate. The reason for CMC to depress the galena flotation could be the promotion of the oxidation of galena.As the characteristic of pingjiang copper-lead-zinc ores, the flotation process of mixed flotation of lead and copper minerals as lead-copper concentrate first, then separation test of copper and lead would be carried out after removing the residual collector adsorbed on the concentrate. And the separation index was good.