METHOD OF PRODUCING CARBONATES OF RARE-EARTH ELEMENTS Russian patent published in 2020 - IPC C22B59/00 C01F17/247 C01B32/60 

FIELD: metallurgy.

SUBSTANCE: invention relates to hydrometallurgy of rare-earth elements (REE), in particular to a method of producing neodymium carbonate, used in production of neodymium metal and neodymium oxide for various regions: production of catalysts, electronic ceramics, pigment in glass production, etc. Method involves deposition of neodymium carbonate from an initial solution of neodymium nitrate, filtration of the residue and its drying. Initial solution containing 40 to 263 g/l of Nd₂O₃ and 4 to 30 g/l of HNO₃ is fed into 20 % solution of a salt of carbonic acid – ammonium carbonate (NH₄)₂CO₃ or ammonium bicarbonate NH₄HCO₃ under isothermal conditions 39–44 °C at pulp mixing speed of 200–1,100 rpm. Excess carbonic acid salt is not less than 35 % of the stoichiometrically required amount. When using ammonium carbonate, the initial solution is fed at a rate of not more than 1.3 kg of Nd₂O₃/(kg (NH₄)₂CO₃ h), and when using ammonium bicarbonate, the initial solution is fed at a rate of not more than 0.8 kg of Nd₂O₃/(kg NH₄HCO₃·h).

EFFECT: method achieves acceptable for the production of specific velocity filtering carbonate neodymium slurry – at least 1 m³/(m² h) without pre-adjustment of acidity and concentration of Nd₂O₃ starting nitrate solution of neodymium, and also decrease the volume of waste water in 1½–2 times.

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