RU2013151413A - CALCINATE METHOD FOR PRODUCING LITHIUM CARBONATE FROM LITHIUM-BASED RAW MATERIALS - Google Patents

Abstract

1. Calcine method for producing lithium carbonate from lithium-containing raw materials, including obtaining a productive lithium-containing solution, its purification from impurities, reagent deposition of lithium carbonate with a carbon ammonium precipitator, separating precipitated lithium carbonate from the mother liquor, washing and drying the precipitate, characterized in that the deposition of lithium carbonate from a purified productive lithium-containing chloride or sulfate or nitric acid or mixed solution is carried out by treating it with a gas mixture of ammonia and carbon dioxide o gas taken in the ratio 2: 1, when cooled in a stepwise-countercurrent mode of contact of the liquid and gas phases; from the mother liquor after separation of lithium carbonate, the ammonium salt of chloride or nitrate is salted out by adding the corresponding lithium salt or a solution saturated with it; precipitated ammonium salt crystals — NHCl or NHNO — are separated from the mother liquor, washed with water, and a saturated solution of ammonium salt is prepared from the washed crystals, which is heated in a heat recovery unit and calcined by contact with quicklime or slaked lime; the ammonia released in this case in a mixture with carbon dioxide, obtained simultaneously with lime by thermal decomposition of limestone, is sent to the deposition of lithium carbonate; the hot mother liquor of the calcination operation is aerated with air, removing residual ammonia, which is absorbed from the air stream by the diluted and acidified solution of the ammonium salt salting operation; an ammonia-absorbing productive lithium-containing solution - absorbent, is sent to the LiCO deposition operation; cleared

Claims (6)

1. Calcine method for producing lithium carbonate from lithium-containing raw materials, including obtaining a productive lithium-containing solution, its purification from impurities, reagent precipitation of lithium carbonate with a carbon ammonium precipitator, separating precipitated lithium carbonate from the mother liquor, washing and drying the precipitate, characterized in that the deposition of lithium carbonate from a purified productive lithium-containing chloride or sulfate or nitric acid or mixed solution is carried out by treating it with a gas mixture of ammonia and carbon dioxide o gas taken in the ratio 2: 1, when cooled in a stepwise-countercurrent mode of contact of the liquid and gas phases; from the mother liquor after separation of lithium carbonate, the ammonium salt of chloride or nitrate is salted out by adding the corresponding lithium salt or a solution saturated with it; precipitated ammonium salt crystals - NH ₄ Cl or NH ₄ NO ₃ , are separated from the mother liquor, washed with water and from the washed crystals a saturated solution of ammonium salt is prepared, which is heated in a heat recovery unit and calcined by contact with quicklime or slaked lime; the ammonia released in this case in a mixture with carbon dioxide, obtained simultaneously with lime by thermal decomposition of limestone, is sent to the deposition of lithium carbonate; the hot mother liquor of the calcination operation is aerated with air, removing residual ammonia, which is absorbed from the air stream by the diluted and acidified solution of the ammonium salt salting operation; an ammonia-absorbing productive lithium-containing solution - an absorbent, is sent to the precipitation operation Li ₂ CO ₃ ; purified from ammonia, the air is returned to the aeration of the solutions after calcination. 2. The method according to claim 1, characterized in that after washing the crystals of ammonium salt (NH ₄ Cl or NH ₄ NO ₃ ), the washing solutions are mixed with the mother liquor of the ammonium salt precipitation operation, and the washing solution resulting from washing the crystals of Li ₂ CO ₃ , is used to dilute the mother liquor of the ammonium salt salting out operation. 3. The method according to claim 1, characterized in that the calcium chloride solution formed during calcination of the ammonium chloride solution is used as a by-product, for example, to obtain anti-icing material. 4. The method according to claim 1, characterized in that when calcining a solution of ammonium sulfate, a precipitate of CaSO ₄ is formed as solid waste, which eliminates the need for salting out (NH ₄ ) SO ₄ and aeration of the mother liquor; the cooled mother liquor is mixed with the washing solutions of the washing operation of CaSO ₄ and Li ₂ CO ₃ and, after purification from impurities, is used to dissolve lithium sulfate to obtain a productive lithium-containing solution or dilute the initial concentrated lithium sulfate solution; the resulting gypsum (CaSO ₄ ) is used in the construction industry. 5. The method according to claim 1, characterized in that during the calcination of the chloride-sulfate solution, part of the resulting calcium chloride solution after air distillation, ammonia is used to desulfate the initial chloride-sulfate mixture or the initial chloride-sulfate lithium salt. 6. The method according to claim 1, characterized in that when calcining a solution of ammonium nitrate after air distillation of ammonia, the resulting solution of calcium nitrate, which is a by-product, is used to obtain a solution of nitric acid by treatment with sulfuric acid and separation of the precipitate formed CaSO ₄ .