Method for recovering silver and palladium from waste

• Main Author: HUANG JUNHAO
• Format: Patent
• Language: English
• Published: 27.05.2015
• Subjects: CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; FERROUS OR NON-FERROUS ALLOYS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The invention relates to a method for recovering silver and palladium from waste, which comprises the following steps: dissolving the waste into nitric acid, filtering out insoluble substances, adding hydrochloride into the obtained solution to obtain a white precipitate and a silver separation solution, adding hydrazine into the white precipitate for reduction to obtain high-purity silver, adsorbing the silver separation solution by an anion exchange resin, eluting with ammonia water, adding hydrochloric acid into the obtained eluate to obtain a yellow precipitate, and adding hydrazine into the yellow precipitate for reduction to obtain high-purity palladium. The nitric acid with low corrosiveness is utilized to dissolve the waste, so the air pollution by denitrification is small. The resin adsorption is adopted to elute the tetrachloropalladate anions, so the palladium recovery rate is high. The method has the advantages of fewer reagent varieties, high atom utilization ratio and high automation degree, and can save the labor cost.