采用H_2SO_4-H_2O_2溶液从含贵金属的富碲渣中选择性提取碲

Selective Extracting Te from Tellurium Richen Residue Containing Precious Metals by H_2SO_4-H_2O_2 Solutions

采用H2SO4-H2O2溶液体系浸出富碲渣中的碲,再用SO2还原含碲浸出液回收碲,使Te得到有效分离,同时富集富碲渣中的贵金属。采用X射线衍射仪(XRD)和扫描电镜(SEM)对粗碲的物相、微观形貌进行表征,结果表明:H2O2(30%)用量和反应温度对Te浸出率影响不大,Te浸出率随反应时间的延长和硫酸浓度的增加而增加;当反应温度为25℃,反应时间为150 min,H2O2(30%)用量为2倍理论用量,H2SO4浓度为4 mol·L-1,硫酸与富碲渣的液固比为6∶1时,Te浸出率达到98.53%;所得铂钯富集物中金、铂和钯的质量分数分别为24.07%,2.47%和5.69%;SO2还原含碲浸出液时,Te回收率随Cl-浓度增加而增加,当Cl-浓度为0.72 mol·L-1时,Te回收率为99.40%,所得粗碲纯度达到95.38%,其物相成分主要为单质态Te,其形貌为柱状体。

Tellurium was effectively separated from tellurium riehen residue, which was leached in H2SO4-H2O2 solutions and fol- lowed by SO2 reduction. In the process mentioned above, the precious metals were also enriched. The crystalline phase and morphology of crude tellurium were investigated by X-ray diffraction （XRD） and scanning electron microscope （SEM）, respectively. The experi- mental results showed that H2O2 （30%） amount and reaction temperature had little effect on tellurium leaching rate, tellurium leaching rate increased with reaction time prolonging and H2 SO4 concentration increasing. The optimum reaction parameters were proposed as follows： reaction temperature of 25℃ , reaction time of 150 rain, two times of theoretical value for amount of H2O2 （30%） , H2 SO4 concentration of 4 mol .L^- 1, liquid/solid ratio of 6：1 between sulfuric acid and tellurium rich residue. In the optimum parameters men- tioned above, tellurium leaching rate reached 98.53% , the mass fractions of gold, platinum and palladium in platinum-palladium rich- en materials were 24.07% , 2.41% and 5.69% , respectively. Tellurium recovering rate increased with C1- concentration increasing during the process that the leachate containing tellurium was reduced by SO2. When C1- concentration was 0.72 mol.L^-1 , the tellurium recovering rate and the purity of the crude tellurium reached 99.40% and 95.38% , respectively. The phase component of crude tellurium mainly was elemental Te, and its morphology was columnar body.