Abstract Cyanide leaching, as a typical traditional method, hardly achieves the cleaner production of gold due to high consumption of auxiliary materials, inefficient production and heavy environmental pollution. In this work, stepwise thiourea leaching was used to extract gold and silver from refractory gold concentrate calcine. In the first stage, gold and silver extractions of 84.42% and 44.15% are obtained by thiourea leaching without any additive, respectively, which are further enhanced to 88.71% and 52.65% by adding the additives of lignin sulfonate sodium, urea and iron ion. The spent thiourea can be recycled to leach next batch of calcine after the treatment of replacing gold by iron powder. In the second stage with mechanical activation, higher gold and silver extractions are achieved 96.51% and 70.43%, respectively. Furthermore, a pilot-scale test is carried out to prove the reliability of this technology, which is hopefully adopted in industry to extract gold and silver efficiently and cleanly

中文翻译：

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硫脲从难熔金精矿煅烧中逐步提取金银

摘要 氰化浸出作为一种典型的传统方法，由于辅料消耗大、生产效率低、环境污染严重，难以实现黄金的清洁生产。在这项工作中，逐步硫脲浸出用于从难熔金精矿煅烧中提取金和银。第一阶段采用硫脲浸出，不加任何添加剂，分别得到84.42%和44.15%的金和银提取物，通过加入木质素磺酸钠、尿素和铁离子等添加剂进一步提高到88.71%和52.65%。废硫脲经铁粉代金处理后，可循环用于浸出下一批煅烧。在机械活化的第二阶段，金和银的提取率分别达到 96.51% 和 70.43%。此外，