含铜金精矿焙烧——酸浸对金、银浸出率的影响

某黄金冶炼厂采用焙烧—酸浸—氰化浸出工艺处理含铜金精矿。针对金、银浸出率偏低的情况,进行了工艺条件优化。通过单因素对比试验,考察焙烧温度、焙烧时间、酸浸酸度、酸浸时间和矿物粒度对金、银浸出率的影响。结果表明:在焙烧温度为650℃,焙烧时间为1 h,酸浸酸度为25 g/L,酸浸时间为1 h,-0.074 mm含量占90%的条件下,进行氰化浸出,金、银浸出率分别达到97.13%和67.56%,分别提高了6.87%和14.80%,取得了良好的工艺指标。

含氰贫液酸化产物中铜元素回收工艺研究

金精矿焙烧—氰化系统含氰贫液闭路循环需要定期开路部分贫液,贫液中的Cu元素具有一定的回收价值,本文在含氰贫液酸化法处理工艺基础上探索含氰贫液中Cu元素回收工艺的可行性。酸化处理后CN-挥发率为95.42%,铜沉淀率为97.82%。酸化后贫液固液分离所得酸化沉淀含铜22.77%～35.01%,采用焙烧—酸浸—萃取工艺回收铜,最佳实验条件如下：焙烧温度为640℃,液固比为5∶1,H2SO4质量浓度为5%,酸浸时间为3 h,此时可获得铜浸出率为92.27%～95.00%。以20%Lix984作为萃取剂,调节浸出液p H=2.3,有机相和水相相比为1∶1,萃取时间为3～5 min时,单级铜萃取率为98.96%;酸化后贫液固液分离所得液体平均铜浓度为72.89 mg/L,以硫化法深度沉淀铜,当Na2S用量为0.4～0.6 g/L,沉淀时间为1 h时,铜沉淀率为92.21%～99.09%。

Separation of halogens and recovery of heavy metals from secondary copper smelting dust

The separation of halogens and recovery of heavy metals from secondary copper smelting(SCS)dust using a sulfating roasting−water leaching process were investigated.The thermodynamic analysis results confirm the feasibility of the phase transformation to metal sulfates and to gaseous HF and HCl.Under the sulfating roasting conditions of the roasting temperature of 250°C and the sulfuric acid excess coefficient of 1.8,over 74 wt.%of F and 98 wt.%of Cl were volatilized into flue gas.Approximately 98.6 wt.%of Zn and 96.5 wt.%of Cu in the roasting product were dissolved into the leaching solution after the water leaching process,while the leaching efficiencies of Pb and Sn were only 0.12%and 0.22%,respectively.The mechanism studies indicate the pivotal effect of roasting temperature on the sulphation reactions from various metal species to metal sulfates and the salting out reactions from various metal halides to gaseous hydrogen halides.