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Sun H.Y.,Honghe University | Kong X.,Honghe University | Sen W.,Yunnan Tin Group Holding Company Ltd | Liu G.Y.,Honghe University
Asian Journal of Chemistry | Year: 2015

The mechanical activation of zinc dusts to enhance leaching of zinc and lead going into leaching residue with direct sulphuric acid leaching have been performed in the paper. Some technical parameters were mainly investigated and optimized, including concentration of initial acid, liquid-solid ratio, leaching time and leaching temperature. The SEM measurement and DTA-TG analysis were conducted to check the change of microstructure and thermodynamics stability of zinc dusts before and after mechanical activation for 0.5 h. It was found that before mechanical activation the optimum technical conditions were concentration of H2SO4 175 g/L, liquid-solid ratio 7:1, leaching temperature 80 °C, leaching time 60 min and leaching rate of zinc was 92.47 % and rate of lead going into leaching residue was 90.83 %. After 0.5 h milling, the optimum technical parameters were concentration of H2SO4 150 g/L, liquid-solid ratio 5:1, leaching temperature 50 °C, the leaching time 40 min and leaching rate of zinc was 91.52 % and rate of lead going into leaching residue was 95.36 %. Source


Wei W.,Yunnan Tin Group Holding Company Ltd | Chai X.-B.,Yunnan Tin Group Holding Company Ltd
Yejin Fenxi/Metallurgical Analysis | Year: 2015

Platinum and palladium in copper leaching residue were captured into gold-silver composite granule by lead fire assaying method. Then, the gold-silver composite granule was dissolved with nitric acid (1+7). After the solution was pouring out, the residues were dissolved with aqua regia(1+1). Merging the solutions above, the hydrochloric acid (1+1) was added to precipitate the silver. After filtration, the content of platinum and palladium in filtrate was determined. Thus, a method was established for determination of platinum and palladium in copper leaching residue by inductively coupled plasma atomic emission spectrometry (ICP-AES). The interference tests of gold and silver in gold-silver composite granule indicated that the absorption of platinum and palladium by silver chloride precipitate could be eliminated through continuous stirring in precipitation process. Meanwhile, gold in solution had no interference with the determination. The proposed method was applied to the determination of copper leaching residue actual samples. The relative standard deviations of the results (RSD, n=11) were 5.6%-9.7%, and the recoveries were between 94% and 104%. The content of platinum and palladium in control samples of copper leaching residue was determined by proposed method. The results were consistent with the reference values. ©, 2015, Central Iron and Steel Research Institute. All right reserved. Source

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