METHOD OF PREPARING CRYSTALLINE PALLADIUM DICHLORIDE Russian patent published in 2008 - IPC C01G55/00 

FIELD: inorganic synthesis.

SUBSTANCE: invention relates to chemistry and technology of platinum metals and provides a method for preparing crystalline palladium dichloride comprising dissolution of palladium in concentrated aqueous hydrochloric acid in presence of oxidant, evaporation of resulting solution, crystallization of palladium dichloride, and drying of precipitated crystals. Evaporation of solution is performed in rotary evaporator in two step: first at temperature to 110°C until palladium dichloride crystals begin precipitate on the walls of evaporation flask and then when adding high-boiling acid solution to evaporation flask. High-boiling acid is selected from sulfuric, phosphoric, and methanesulfonic acids, which form with palladium compounds less stable than chloride complexes of palladium, and it is used in amount corresponding to 1 L acid per 3-5 kg palladium present in salt form in solution being evaporated. Further, mother liquor is separated and palladium dichloride crystals are washed on filter with distilled water at solid-to-liquid phase ratio (3-4):1.

EFFECT: reduced process time, diminished hydrochloric acid emission, increased direct palladium recovery, lowered equipment corrosion, and improved operation condition.

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