The hydro-metallurgical treatment of recycling material usually begins with leach processes using aqua regia or hydrochloric acid, in which a precious metal salt solution is produced.
As the first step of crude purification, the separation of precious metals from non-ferrous metals as well as the separation of the individual precious metals takes place by precipitation, extraction or distillation. In the following steps of the fine purification, individual precious metal salts are further purified in the corresponding purification lines using selective and continuous steps of dissolving and re-precipitation.
The pure precious metals in accordance with ASTM standard are then achieved by chemical or electro-chemical reduction. Acidic reaction gases or nitrogen oxides developed during these hydro-metallurgical processes are removed by suitable scrubber systems from the exhaust air.
