Precious Metal Refining

11.1. Precious Metal Recycling and Environmental Protection

Precious metal containing products which after a certain time become obsolete or are generated as non-usable manufacturing scrap, are used widely in industry and the private household sector. Therefore it is very important to return these expensive residues to the use-cycle of precious metals by reclaiming the contained pure metals such as gold, silver, platinum, palladium, and rhodium (Fig. 11.1).

Fig. 11.1: Precious metals in various forms

Precious metal recycling is nowadays closely related to the protection of the environment. It is integrated into a complex network of processes that benefit the clean supply of water and protection of the air quality. The wastewater streams generated during refining processes are treated by special processes which remove hazardous components. High efficiency wet scrubbing and filtration of exhaust air is employed in all stages of the metal recycling processes.

11.2 Refining Methods

The precious metal containing products and materials submitted into the refining process are generally called precious metal scrap (Fig. 11.2). They are usually classified into three categories which differ by the refining processes employed and by the cost-to-value ratio.

Main Articel: Refining Methods