Comprehensive recovery method for platinum and palladium in silver anode slime

Abstract

The invention discloses a comprehensive recovery method for platinum and palladium in silver anode slime. The method comprises the steps that the silver anode slime generated through silver electrolysis is subjected to nitric acid leaching in a reaction still for silver separating; the leaching conditions comprise that the mass concentration of a nitric acid solution is 30-40%, the liquid-solid ratio is 3-8:1, the temperature is 40-80 DEG C, and the time is 2-6 h; filtration is conducted after leaching, and silver separating solution and leaching residues are obtained; hydrochloric acid or sodium chloride is added into the silver separating solution for silver sedimentation, the reaction endpoint is reached when no white sediment exists, and silver chloride sediments and a silver sedimentation solution are obtained after filtration; a sedimentation agent is added into the silver sedimentation solution, platinum and palladium in the solution and a small amount of silver, lead, bismuth and copper are precipitated and recycled, and platinum and palladium concentrates and a platinum and palladium sedimentation solution are obtained after filtration. The leaching residues are chloridized for gold separating, a gold separating solution and gold separating slags are obtained, the gold separating solution is subjected to bismuth removal, a gold stock solution and bismuth sedimentation slags are obtained, and gold powder, a gold sedimentation solution and valuable metal such as associated silver, associated lead, associated bismuth and associated copper are further obtained. According to the method, the platinum and palladium in the silver anode slime can be recycled effectively through the sedimentation agent under the ambient temperature condition, and the platinum and palladium concentrates are obtained; meanwhile, the valuable metal such as associated gold, associated silver, associated lead, associated bismuth and associated copper are enriched and recycled, the comprehensive recycling of resources is achieved, the recycling level of the resources is improved, and the economic benefits are remarkable.

Description

technical field [0001] The invention relates to a comprehensive recovery method for platinum and palladium in silver anode slime, and belongs to the technical field of comprehensive recovery and production of valuable metals in silver electrolysis anode slime. Background technique [0002] During the silver electrolysis process, there are 50-70% palladium in the silver anode plate, and 90-95% platinum distributed in the silver anode slime. Therefore, it is necessary to enrich and recover platinum and palladium from silver anode slime to create economic benefits. [0003] At present, the production methods for recovering platinum and palladium from silver anode slime mainly include: adding zinc powder replacement method and butyl xanthate precipitation method from platinum and palladium enrichment solution. The zinc powder replacement method has disadvantages such as high zinc content in the replacement slag, low platinum and palladium grade, difficult leaching in subsequent...

AI Technical Summary

Problems solved by technology

The zinc powder replacement method has disadvantages such as high zinc content in the replacement slag, low platinum and palladium grade, difficult leaching in subsequent refining and purification, and generation of toxic and harmful gases; the existing technology of the butyl xanthate precipitation method requires high temperature conditions (60~80°C) Precipitation of platinum and palladium, heating consumes energy and butyl xanthate is easy to decompose under high temperature conditions to produce carbon disulfide, nitrogen oxides, hydrogen chloride and other toxic and harmful gases, polluting the environment and endangering the health of front-line workers

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