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The zinc-containing dust was oxidatively pretreated with calcium hypochlorite,subsequently leached with ammonia/ammonium bicarbonate solution to obtain the ammoniacal leaching solution,and zinc oxide was produced by ammonia distillation of the ammoniacal leaching solution and subsequent calcination. The elements of iron and manganese could not be detected in ammoniacal leaching solution,and the extraction rate of zinc was 98.2% in ammoniacal leaching process. The zinc oxide content in the product is 99.5%(ω),and the contents of iron and manganese in the product were 0.002 8‰ and 0.000 84‰(ω), respectively. The analyses of the valence states of iron and manganese in the zinc-containing dust with and without pretreatment were performed by chemical analysis and XPS,and the possible oxidation mechanism of the oxidative pretreatment of the dust was discussed. It is concluded that Fe 2+-oxide and Mn 2+-oxide in the dust were oxidized to Fe 3+-oxide and/or its hydrate and Mn 4+-oxide and/or its hydrate by calcium hypochlorite during the oxidative pretreatment process,respectively. 相似文献
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Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied.The effects of relative amount of metallic impurities,dosage of zinc dust,purification time,temperature,pH value and total ammonia concentration in the solution on the purification of the solution were investigated.The results indicate that total ammonia concentration in the solution had no effect on the purification,but relative amount of metallic impurities,dosage of zinc dust,purification time,temperature and pH value of the solution were the main factors influencing the purification.Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium.Nevertheless,the presence of cobalt went against the cementation of cadmium and cobalt.All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage,1 h of purification time,35℃,pH value 9.03 of zinc ammoniacal leaching solution.The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning. 相似文献
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采用铁粉还原法回收含金滤液中的金、银、铜等有价金属。考察了铁粉添加量、还原时间、还原温度对金属置换率的影响。结果表明,当铁粉添加量为5kg/m~3,在40℃反应30min,含金滤液中金、银、铜含量分别从2.4、53、950mg/L降至0.05、0.4、7mg/L。置换后所得滤饼中金、银、铜分别达到386.8g/t、5 521.7g/t和29.8%。 相似文献
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采用偏重亚硫酸钠—空气法处理氰化尾渣进行脱氰的研究,考察Na2S2O5浓度、Cu2+浓度、空气速率、初始pH和反应时间对脱氰效果的影响。结果表明,在Na2S2O5浓度0.2g/L、Cu2+浓度80mg/L、空气鼓入速率250mL/min、初始pH≈10的条件下反应2h,氰化尾渣矿浆中全氰浓度从91.5mg/L降到0.2mg/L左右,可以满足GB8978-1996污水综合排放标准。 相似文献
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铜铟镓硒太阳能电池(CIGS)芯片废料中硒元素具有很高回收价值。开展了从废旧CIGS电池材料硫酸浸出液中回收硒的研究。对比了铜粉、亚硫酸钠和二氧化硫3种还原剂的沉硒效果,结果表明,二氧化硫的沉硒效果好、同时酸浸液中杂质元素几乎不发生共沉淀,具有很好的选择性。考察了试验温度、二氧化硫流量和初始酸浓度对沉硒效果的影响,得出优化试验条件如下:CIGS硫酸浸出液初始酸浓度20 g/L,100 mL酸浸液中以1.8 L/h的流量通入SO2,在80 ℃下反应2 h。在优化条件下,硒的沉淀率可达94.51%左右,所得粗硒沉淀中硒含量约为95.67%。为废旧CIGS材料回收提供了一种有效的方法。 相似文献