从化学实验室回收的、含有银的废液,都倒在一个容器中。不从容器中除去沉淀。加入过量的盐酸。仔细搅动容器中的内容物。此时,溶液中的银已转变成沉淀。如铬酸银,这样的银盐沉淀也要转变成难溶性的氯化银。加盐酸的同时,还能从溶于盐酸的,其他各种金属化合物中释出银沉淀来。这些化合物,在合并废液时,包藏了银的沉淀。然后,过滤沉淀。用稀盐酸洗涤,后用水洗涤。将沉淀移至大锥形瓶中,加入过量的,新制的硫化铵或硫 Recycled from the chemical laboratory, containing silver waste, are poured in a container. No sediment is removed from the container. Add excess hydrochloric acid. Carefully agitate the contents of the container. At this point, the solution of silver has been transformed into a precipitate. Such as silver chromate, this silver salt precipitation also transformed into insoluble silver chloride. Add hydrochloric acid at the same time, but also soluble in hydrochloric acid, and other various metal compounds released silver precipitation. These compounds, when combined with waste, contain silver deposits. Then, the precipitate is filtered. Wash with dilute hydrochloric acid and then with water. The precipitate was transferred to a large Erlenmeyer flask and an excess of freshly prepared ammonium sulphide or sulfur was added