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Zhang F.,Central South University | Zhang F.,Henan Zhongyuan Gold Smelter Co. | Xiong L.,Henan Zhongyuan Gold Smelter Co. | Zheng Y.,Central South University | Ma Y.,Central South University
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2016

The oxidation roasting method with adding NaCl was proposed to recover selenium from the gold concentrate roasting acid mud. The grain size and chemical composition analysis were done on acid mud. The results showed that more than 70% selenium of acid mud existed in the form of simple substance. The particle size of less than 150 μm and less than 75 μm accounted for 62.39% and 47.04%, respectively. The particle size was small and its distribution was uniform. Oxidation roasting and efficient reduction method were processed by orthogonal experiment and single factor experiment analysis method. The optimum reaction parameters were as following: oxidant sulfuric acid added coefficient of 1.4, NaCl added coefficient of 12, roasting for 4 h at 510℃, under which selenium gasification rate could reach 99.03%.The roasted flue gas were absorbed by alkaline solution and treated by efficient reduction method. The grade of crude selenium reached 96.30% after reduction,and the recovery rate reached 98.09%. The crystalline phase and micro morphology of acid mud, roasted product and crude selenium were investigated by X-ray diffractometry (XRD) and scanning electron microscopy (SEM), respectively. The results showed that acid mud granules were complex structure with size inequality, the roasted product particles were relatively uniform, and the micro morphology of crude selenium presented uneven granular spherical particles with 1~5 μm in diameter size. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.

Zhang F.-Y.,Central South University | Zhang F.-Y.,Henan Zhongyuan Gold Smelter Co. | Zheng Y.-J.,Central South University | Sun Z.-M.,Central South University | And 2 more authors.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2015

By using sodium sulfite as reductant and Cl- and composited halogen ions as catalysts, selenium and tellurium were recovered and gold, platinum and palladium were captured from precipitated gold solution that was leached by chlorination and reduction from copper anode slime. The crystalline phase and the morphology of reduction product were investigated by XRD and SEM, respectively. The results show that the reduction rates of selenium, gold, platinum and palladium are 100.0% and the reduction rate of tellurium is 97.7% when Cl- concentration is 1.1 mol/L,reaction temperature is 85 ℃,reaction time is 1 h, H2SO4 concentration is 368 g/L and Na2SO3 concentration is 100 g/L. The reaction speed is faster than that of NaCl catalyst when the molar ratio of NaCl to NaBr in the complex catalysts is 1:2. The mass fractions of tellurium, copper, selenium, gold, palladium, platinum in reduction product are 73.95%, 12.35%, 7.65%, 3.31%, 0.95%, 0.24%, respectively. Tellurium exists in the form of simple substance in the reduction product, the morphology of the product is columnar body. ©, 2015, Central South University of Technology. All right reserved.

Peng G.,Henan Zhongyuan Gold Smelter Co. | Peng G.,Henan Province Key Laboratory of Gold Resource Utilization | Zhang Y.,Henan Zhongyuan Gold Smelter Co. | Zhang Y.,Henan Province Key Laboratory of Gold Resource Utilization | And 4 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2015

According to the X-ray fluorescence (XRF), multi-element analysis and selenium phase analysis results, a hydrometallurgical treatment process was studied. The treatment process was determined by the effects of different treatment enhanced leaching agents. The influence of different factors on enhanced leaching was studied, and the effect of different reduction factors on the reducing rate was studied. The results showed that the optimal conditions were as follows: sulfuric acid of the enhanced leaching agent, liquid to solid weight ratio of 1.5:1.0, leaching time of 2.5 h and leaching temperature of 90℃. Under the optimal conditions, the selenium grade of leached residue was less than 0.5%, and leaching rate was 99.99%. The optimal reducing conditions were as follows: the temperature of 70℃, the chloride ion concentration of 0.06 mol·L-1, sodium sulfite amount of 1.2 times the theoretical amount. The selenium content in the solution was less than 0.03 mg·L-1, the selenium reduction rate was 99.99%, the selenium content in crude selenium was 93%, and the total recovery of selenium reached 96.7% under the optimum conditions. The recovery of Se from high-lead selenium materials was realized. And the selenium could be simply and efficiently treated by this process. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.

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