METHOD OF RECYCLING SPENT CHROME PLATING ELECTROLYTES Russian patent published in 2015 - IPC C02F1/62 C02F1/70 C02F9/10 C02F101/22 C02F103/16 

FIELD: chemistry.

SUBSTANCE: method includes treating electrolytes with 10-30% aqueous sodium sulphate solution Na₂SO₃ in amount of 3.63-3.64 mg per 1 mg Cr⁶⁺ at pH 2.5-3.0 and alkanisation with sodium hydroxide NaOH solution to pH 8.0-9.5. The obtained precipitate is washed, dried at 200-220°C for 1-2 hours, then annealed at 900-1100°C for at least 1 hour and subjected to metallothermic reduction to chromium metal.

EFFECT: reduced reactant consumption with simultaneous increase in efficiency of treatment and the quality of the obtained product by reducing the mass of the formed sludge and the amount of impurities which hinder metallothermic reduction.

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