No abstract

Wastes amalgams were collected from dental cabinets of the northwest region of the Parana State, Brazil. Amalgams collected were washed with 0.1M nitric acid and distilled water, dried at 80°C, and crushed to 1OO mesh. Digestion of the brown powder was performed using two types of reactors. The first was made of pyrex glass and the second reactor of stainless steel, both connected to a PVC tube with Mn02 and a vacuum pump. The efficiency observed was higher for the second reactor, with 96-98% of mercury recovered, and the minimum time necessary for digestion was 180 minutes. After the digestion, the mercury was transferred to a conventional apparatus for mercury distillation and purification. The distillation was performed two times and the final mercury recovered was 99% pure. Silver and tin were also recovered by chemical and electrochemical methods after the mercury separation.