REFINING AND TREATMENT OF PALLADIUM FROM SECONDARY RESOURCES
Abstract
Palladium extraction and refining is a complicated chemical process consisting of the repeated chemical dissolution and selective precipitation of Pd salt. There is necessary to suggest a specific process variation of every type of Pd input. Chemical technology of the treatment of palladium slime obtained from the silver electrolysis at Ag-Pd electronic scrap treatment were tested and verified in the laboratory scale by authors of this paper.
Chemical reactions of the palladium dissolution, selective precipitation and reduction processes are described and their thermochemical data are discussed. The individual steps of the technological flow sheet of palladium extraction and refining is described in the second part of this work. Palladium slime is leached by aqua regia, and then palladium - chloride salt is precipitated by ammonium chloride. After annealing and reduction in hydrogen atmosphere is Pd - sponge obtained with purity of 95 wt. % Pd. After refining of this Pd sponge by repeating of the same processes were Pd sponge with purity of 99 wt. % Pd and 95 % efficiency obtained.
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