New Technology On Atmospheric Leaching Of Valuable Elements In Polymetallic Sulifid Residue

Abstract:The research in the paper mainly related to the development of a novel high-efficiency method which reclaiming valuable metals from the metal sulfide residues. Specifically, the treatment processes, current research situation and valuable metals applications of the two typical metal sulfide residues (low grade lead concentrate and slag produced by cyanidation slag flotation and neutralizing wastewater respectively) have been summarized. Besides, the oxidation leaching with X system and washing by alkaline-leaching by mixed acids-alkali copper methods are developed to process the residues above, and good results are achieved.1) Preparing standard lead and zinc concentrate from low grade lead concentrate:when using the traditional zinc leaching-lead into slag method,87.56%is the highest leaching rate of zinc, but the leaching rate of iron can also reach as high as90.89%, which inhibits the separation and recycling of zinc. New method with X system at room pressure is formed to improve the process after we studying the relationship between leaching potential, oxidants, total acid content, reagent B, leaching time, leaching temperature and zinc reclaiming rate, grade of zinc concentrate, leaching rate of lead. As a result, lead concentrate and zinc concentrate with the grade of75.49%and45%respectively are obtained after3hours’leaching at70℃twice by controlling the amount of reagent A at15.6g/L, B at90g/L, Liquid/Solid=10/1, O2at1.5L/min in the efficient reaction tank. Besides, the grade of sulfur obtained reaches99%. So the reclaiming rates of lead, zinc and the elemental sulfur are90.68%,99%and99.1%respectively, and the impurity contents of lead and zinc concentrate meet the related quality standards of China.2) Separating and reclaiming copper, gold and silver from the slag produced by neutralizing wastewater:the process is as follows: dechlorination by alkaline-leaching copper by mixed acid-precipitating silver-purification-precipitating copper by sodium carbonate, the research concentrates on the relationship between oxidants, reagent C, reagent D, leaching time, leaching temperature, liquid-solid ratio, washing dechlorination by alkaline and the leaching efficiencies of copper and gold. As a result, copper and gold-silver can be separated by leaching the slag processed by dechlorination in mixed acids (composed of reagent C and D) at85℃for1.5h and controlling the amount of reagent C at2.24mol/L, D at0.3mol/L and liquid-solid ratio at6:1. The leaching efficiency of copper is91.54%, and after purification and precipitating copper, the basic cupric carbonate with50.4%grade can be obtained. Finally, the reclaiming ratios of copper, gold and silver are90%,99.8%and99.8%respectively. The copper reclaiming ration is the highest compared with that of processing copper sulphide by other ways, also, the method mentioned in the part is easy, environmental-friendly and economic.