METHOD OF PROCESSING EUDIALYTE CONCENTRATE Russian patent published in 2002 - IPC

FIELD: nonferrous hydrometallurgy. SUBSTANCE: objective of invention is integrated technology of eudialyte concentrate to produce zirconium, rare-earth elements, aluminum, and manganese compounds. Eudialyte concentrate is treated with concentrated sulfuric acid and resulting pulp is diluted with sodium sulfate solution to transfer into solution zirconium, aluminum, iron, manganese, and sodium. Undissolved residue containing rare-earth elements is separated and washed with water. After that, aluminum is recovered from solution in the form of ammonium or potassium alums by adding excess of ammonium or potassium sulfates, carbonates, or hydroxides at 10-20 C. After separation of alums, solution is neutralized with sodium carbonate or hydroxide, which provokes separation of zirconium. Zirconium-free solution is neutralized with sodium hydroxide to pH 8.5-9.0, iron and manganese hydroxides are separated, solution is evaporated to 20-30% sodium sulfate concentration, cooled to 10-20 C, and sodium sulfate precipitate is separated. From undissolved residue, rare-earth elements are recovered by converting their sulfates into nitrates or chlorides. After separation of sodium sulfate, exhausted solution is used to dilute pulp. EFFECT: increased fullness of eudialyte concentrate processing. 9 cl, 4 ex