The invention discloses a
lithium carbonate preparation method, which comprises: enriching natural
spodumene into a concentrate, feeding into a
rotary kiln,
roasting to convert alpha-
spodumene in theore into beta-
spodumene, stopping the heating, and naturally cooling; crushing when the temperature of spodumene is reduced to 80-120 DEG C, screening, adding excess concentrated
sulfuric acid, feeding into a converter,
sintering, and leaching the
sulfuric acid sintering block by using water to prepare water-soluble
lithium sulfate; neutralizing the excess
sulfuric acid to achieve the pH value of5.5-6.5, filtering, removing
calcium,
magnesium, iron and aluminum from the filtrate, carrying out decolorization, and concentrating the material liquid to prepare a saturated
lithium sulfate solution; and adding a saturated
sodium carbonate solution to the saturated
lithium sulfate solution to generate
lithium carbonate precipitate, separating the precipitate to obtain
lithium carbonate with a product purity of more than 70%, repeatedly washing with hot water to obtain
lithium carbonate with a purity of 96-97%, and
drying to obtain the product. According to the present invention, the preparation method is simple, the
energy consumption is greatly reduced, and the
economic benefits of the enterprise are improved.