高校化学实验废液中银的提取

Extraction of Silver from Chemical Experiment Waste Liquid in the University

在含银废液中加入氯化钠生成氯化银沉淀,然后用氢氧化铵溶解沉淀,再用水合肼还原,制得单质银。提取的银粉的纯度是用佛尔哈德法测定的。实验结果表明:银的回收率为91.11%,纯度为96.11%,结果满意。并探讨了氢氧化铵溶解氯化银的最佳配比。

Adding sodium chloride to generate silver chloride in silver-containing waste liquid, dissolving silver chloride with ammonia water, then reducing silver ammonia solution by hydrazine hydrate,we could obtain elemental silver. The purity of the extracted silver powder was determined by Volhard method. The result showed that the recovery of silver was 91.11 %, the purity of that was 96.11 %. The optimum proportion of silver chloride dissolved in ammonia water was also discussed in this paper.