METHOD FOR PROCESSING TUNGSTEN CONCENTRATES Russian patent published in 2016 - IPC C01G41/00 

FIELD: chemistry.

SUBSTANCE: invention relates to pyrohydrometallurgy of tungsten, in particular to extraction of tungsten from scheelite CaWO₄ and wolframite (Fe, Mn) WO₄ concentrates in form of compounds, representing trade products. Method includes processing of tungsten concentrate with ammonium bifluoride with heating with addition of ammonium bifluoride in portions in 2 stages. Processing of tungsten concentrate at each stage is carried out at 170-180°C and total weight ratio of ammonium bifluoride to tungsten concentrate, equal (1.5-2):1, with further leaching of fluorinated product with water, hydrolysis of solution, obtained after leaching, with ammonia solution with separation of residue and evaporation of filtrate to dry salts, containing mixture of ammonium dioxopentafluorotungstate (NH₄)₃WO₂F₅ and ammonium bifluoride NH₄HF₂, heating this mixture at 240°C for sublimation of ammonium bifluoride and obtaining final trade product ammonium dioxotetrafluorotungstate (NH₄)₂WO₂F₄. Processing of tungsten concentrate with ammonium bifluoride at first stage is carried out for 3 h, and at second stage - for 2 h. After each stage of processing of tungsten concentrate with ammonium bifluoride obtained product is cooled to room temperature. In order to perform more complete transfer of tungsten into solution, leaching of fluorinated product is carried out by its triple dissolution in water with S:L equal 1:5, and respectively triple filtration of obtained solution with sediment. Hydrolysis of solution, obtained after leaching, is carried out with concentrated ammonia solution to pH 12.

EFFECT: optimisation of method for processing tungsten concentrates by reduction of process temperature.

5 cl, 1 dwg, 6 ex