METHOD OF PROCESSING NITRATION HYDROXIDES IN REFINERY OF PLATINUM METALS Russian patent published in 2011 - IPC C22B11/00 C22B3/04 C22B3/20 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy of noble metals, in particular, to method of processing nitration hydroxides in refinery of platinum metals containing chalcogenides, tin, arsenium and platinum group metals, gold and silver. Proposed method comprises leaching of hydroxides and extracting basic metal compounds from the solution. Hydroxide leaching is carried out for 1-2 h by alkali solution with concentration of 140-180 g/l with l:S ratio varying from 3:1 to 4:1, temperature 80-90°C, and introducing hydrazine hydrate into pulp to reach OVP of minus 400-600 mV relative to reference silver-chloride electrode. Then, alkaline solution is separated from insoluble residue that concentrates platinum metals. Now, extraction of basic metals is carried out in processing alkaline solution by sulfuric acid to pH=4-5 to produce hydroxide precipitate of tin, arsenium, selenium and tellurium, and by filtration, or processing of alkaline solution by sulfuric acid to pH 0.5-1.0 along with adding iron powder to OVP varying from 0 to minus 100 mV, and filtration of obtained cementates obtained on the basis of selenium and tellurium, and processing the solution by alkali to pH = 4-5 with deposition of tin and arsenium hydroxides. Invention allows extracting up to 85% of Se and Te into target products, 90% of Sn and As into secondary hydroxides at minimum transition (less than 1%) into PMH.

EFFECT: over 99% of platinum metals left in refinery cycle, reduced processing cycle.

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