Amalgam (chemistry) copper trough, which formed a thin coating of mercury on the exterior. The waste ore was then transferred down the trough, and gold in the waste amalgamated with the mercury. This coating would then be scraped off and refined by evaporation to get rid of the mercury, leaving behind somewhat high-purity gold. Mercury amalgamation was first used on silver ores with the development of the patio process in Mexico in 1557. There were also additional amalgamation processes that were created for processing silver ores, including pan amalgamation and the Washoe process. Gold amalgam has proved effective where gold fines ("flour
Dental amalgam controversy the use of dental amalgam, but allows phasing down amalgam use over a time period appropriate to domestic needs, an approach advocated by the World Health Organization (WHO). FDI World Dental Federation recognizes the safety and effectiveness of amalgam restorations. FDI is a federation of approximately 200 national dental associations and dental specialist groups representing over 1.5 million dentists. In collaboration with the WHO, they have produced an FDI position statement and WHO consensus statement on dental amalgam. Their position regarding the safety of dental amalgam is that, aside from rare allergic reactions and local side effects, "the small amount