| 简介 |
FIELD : chemistry.
SUBSTANCE : invention can be used in the chemical industry to produce phosphoric acid, a rare earth element concentrate (REE), alkaline earth metal carbonates and fluorine compounds. Fluorine-containing apatite concentrate is processed with a phosphoric acid solution in the presence of a sulfoxide cation exchanger with transfer of fluorine to the solution. Cation exchanger is used in the sodium or potassium form at a rate of 115–120 % of the metal cations stoichiometrically necessary for the sorption. Then the phosphoric acid is separated from the cation exchanger containing calcium, strontium and REE. After separation of phosphoric acid, the precipitate of sodium or potassium fluorosilicate is isolated from it by filtration or centrifugation. Further from phosphoric acid, the residual amount of sodium or potassium in the form of a solution of hydroxide is removed by electrodialysis. Desorption of calcium, strontium and REE from the cation exchanger with a solution of chloride or sodium or potassium nitrate and stepwise neutralization of the desorbate with a solution of sodium or potassium carbonate. Neutralization of the desorbate is carried out with precipitation of a concentrate of REE carbonates, then calcium carbonate and strontium carbonate concentrate.
EFFECT : invention makes it possible to increase the purity of phosphoric asid by reducing the fluorine impurity content thereof while providing a high degree of phosphorus extraction to phosphoric acid, and also to obtain commodity products in the form of a concentrate of strontium carbonate and sodium or potassium fluorosilicate.
6 cl, 4 ex |
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