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采用银含量在250~400g·t~(-1)、含铜和含锌量均在1.0%(质量分数)以下的钢铁冶金烧结除尘灰为原料,以氨水为络合剂,研究了氨络合浸取回收烧结灰中贵金属银和有色金属铜、锌等元素的方法。利用银与甲醛的银镜反应原理、活泼金属的梯级还原置换原理、碳酸钠与含锌液反应生成碳酸锌沉淀及其煅烧分解反应原理,研究了从银、铜和锌的混合氨络合物中分步分离回收各金属元素并制备其相应单质或化合物产品的工艺路线及工艺条件。结果表明,在浸取过程中较适宜的工艺条件为:氨水浸取时间20min,氨水用量4.12mol·kg~(-1)烧结灰。在此条件下,各烧结灰样中银的浸出率均可达到70%以上。经分步分离回收实验所得的银产物中Ag元素的含量为91.20%,铜产物中Cu元素的含量为86.40%,氧化锌产物中ZnO的含量为98.70%。烧结除尘灰中银、铜和锌元素的总回收率分别为71.20%,60.40%和56.71%。该工艺具有操作简便、回收效率较高、生产成本低等优点,是一条适合于规模化生产的钢铁冶金烧结除尘灰中银及其他有色金属元素回收与综合利用新工艺。
Ammonia metallurgical sintering dust was used as the raw material, with the silver content of 250 ~ 400g · t ~ (-1), copper and zinc content below 1.0% (mass fraction) Combined leaching and recovery of sintered ash in precious metals and nonferrous metals copper, zinc and other elements of the method. The principle of silver mirror reaction between silver and formaldehyde, the principle of step reduction and displacement of active metal, the reaction of sodium carbonate with zinc solution to form zinc carbonate precipitation and calcination decomposition reaction were studied. The effects of silver, copper and zinc mixed ammonia complex Step by step in the separation and recovery of the metal elements and preparation of the corresponding elemental or compound products process route and process conditions. The results showed that the suitable technological conditions during the leaching process were: ammonia leaching time 20min, ammonia dosage 4.12mol · kg -1 sintering ash. Under these conditions, the leaching rate of silver in each sintered ash sample can reach more than 70%. The content of Ag element in the silver product obtained through the step separation and recovery experiment was 91.20%, the content of Cu element in the copper product was 86.40%, and the ZnO content in the zinc oxide product was 98.70%. The total recoveries of silver, copper and zinc in sintering dust were 71.20%, 60.40% and 56.71% respectively. The process has the advantages of simple operation, high recovery efficiency, low production cost and the like, and is a new process for recycling and comprehensive utilization of silver and other non-ferrous metal elements in a metallurgical sintering dust dust for large-scale production.