The invention provides a method for preparing industrial
lithium carbonate by using
salt lake brine with a
high magnesium-to-
lithium ratio. In the method, a TBP-CON-KS+FeCl3 is used as an extraction
system to extract and back-extract
impurity-free
salt lake brine with a
high magnesium-to-
lithium ratio, the residual liquid obtained after back-extraction is converted by alkaline liquor for
precipitation, the precipitate is washed to form an industrial
lithium carbonate product and the
lithium carbonate content is more than or equal to 99.0 percent and is in accordance with the requirements of GB / T 11 075-2003 standards. The method has the advantages that: liquid-liquid extraction with an
organic solvent is adopted to realize the separation of lithium from
magnesium, the
lithium carbonate is precipitated by inorganic slats, the lithium
carbonate is extracted from the
salt lake brine with a
high magnesium-to-lithium ratio, the process is simple, the control is easy, the
operational reliability is high and the application range is wide; a process of
calcination and diluted lithium solution
evaporation and concentration is saved, the
energy consumption is only 30 to 50 percent of that of the conventional process for producing lithium
carbonate by using lithium-containing brine; initial
raw material consumption comparison show that the production cost of the method is only about 8 percent of that of the prior art; and the
raw material brine can return to a
storage pool after the extraction of the lithium carbonate, so no by production disposal problem is involved, environmental
pollution is relatively low and lithium yield in the whole process is more than or equal to 70 percent.