Abstract A pretreatment to remove and recover base metals present in complex sulfide refractory ores is proposed as a method to improve the extraction of precious metals with thiourea. Sodium citrate solutions at pH 8 and 5 were employed to extract lead and iron, respectively, from two concentrates: one having silver in a primarily galena matrix and the other, with gold associated with pyrite. The pretreatment solutions, containing the base metals, were subjected to electrolysis and pH adjustment, before being recycled back to the pretreatment stage. The results showed that citrate pretreatment successfully extracted lead and some iron, liberating the precious metals for thiourea leaching. The citrate pretreatment solution could be reutilized, after base metal removal, decreasing the reagent and water requirements. In all cases, the citrate pretreatment improved precious metal extraction.

中文翻译：

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贱金属柠檬酸盐预处理复合矿石改善硫脲浸出金银

摘要 提出了一种去除和回收复杂硫化物难处理矿石中存在的贱金属的预处理方法，作为一种改进硫脲提取贵金属的方法。使用 pH 值为 8 和 5 的柠檬酸钠溶液分别从两种浓缩物中提取铅和铁：一种在主要方铅矿基质中含有银，另一种含有与黄铁矿相关的金。包含贱金属的预处理溶液经过电解和 pH 调节，然后再循环回预处理阶段。结果表明，柠檬酸盐预处理成功地提取了铅和部分铁，释放了硫脲浸出的贵金属。柠檬酸盐预处理溶液在去除贱金属后可以重复利用，从而减少了试剂和水的需求。在所有情况下，