Lithium carbonate production process and apparatus
AssigneeU.S. Borax Inc.
InventorsAmit Patwardhan, Sandip Shinde, Allen Wattenbarger
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Abstract
A method of forming lithium carbonate from a lithium-bearing solution including: evaporating the lithium-bearing solution to precipitate a first group of impurities; removing the first group of impurities to form a first purified solution; and performing a flash crystallisation step within a predetermined temperature range to crystallise a second group of impurities from the first purified solution; removing the second group of impurities from the first solution to form a second purified solution, wherein at least 90 wt % of lithium is recovered from the first purified solution; and reacting the second purified solution with a metal carbonate to form lithium carbonate of at least 90 wt % purity.
Claims19
A method of forming lithium carbonate from a lithium-bearing solution including:
- evaporating the lithium-bearing solution to precipitate a first group of impurities;
- removing the first group of impurities to form a first purified solution;
- and
- performing a flash crystallisation step within a predetermined temperature range to crystallise a second group of impurities from the first purified solution;
- removing the second group of impurities from the first solution to form a second purified solution, wherein at least 90 wt % of lithium is recovered from the first purified solution;
- and
- reacting the second purified solution with a metal carbonate to form lithium carbonate of at least 90 wt % purity.
The method of any one of the preceding claims, wherein the second group of impurities comprise sodium, potassium and boron-containing impurities.
The method of any one of the preceding claims, including a filtering step to remove the first group of impurities formed during the evaporating step.
The method of any one of the preceding claims, wherein the evaporating step forms a first purified solution having a lithium concentration of at least 3,000 ppm.
The method of any one of the preceding claims, wherein flash crystallisation step recovers at least 95 wt % of the lithium from the first purified solution.
The method of any one of the preceding claims, wherein the flash crystallizing step is performed at a temperature ranging from 10-20° C.
The method of any one of the preceding claims, including a filtering step to remove the second group of impurities formed during the crystallisation step.
The method of any one of the preceding claims, including a second crystallisation step to separate sodium and potassium-containing impurities from the first purified solution.
An apparatus comprises:
- an evaporator to evaporate a lithium-bearing solution to precipitate a first group of impurities and form a first purified solution;
- a crystalliser configured to perform a flash crystallisation step within a predetermined temperature range to crystallise a second group of impurities from the first purified solution and forms a second purified solution, wherein at least 90 wt % of lithium is recovered from the first purified solution;
- a reactor configured to react the second purified solution with a metal carbonate to form lithium carbonate of at least 90 wt % purity;
- and
- the crystalliser is configured to receive recycled lithium-bearing liquor recycled from the reactor.
Dependencies are inferred from the claim text.