| 摘要 |
<p>1. A process (10) for the production of lithium carbonate, the process characterised by the steps of: (i) Calcining (20) an alpha-spodumene ore or concentrate (12) to produce beta-spodumene; (ii) Sulphating (28) the beta-spodumene at elevated temperature; (iii) Passing the sulphated beta-spodumene to a leach step (30) in which lithium sulphate is leached in water; (iv) Passing the pregnant leach solution from the leach step to a series of impurity removal steps in which iron, alumina, silicates and magnesium are, in large part, precipitated and removed (34, 36 and 38); (v) Adding sodium carbonate (42) to the product of step (iv) by which calcium is precipitated (40); (vi) The product of step (v) is then passed to an ion exchange step (50) in which residual calcium, magnesium and other remaining multivalent cations are substantially removed; and (vii) Passing the purified product of step (vi) to a lithium carbonate precipitation step (56) in which sodium carbonate (54) is added to produce precipitated lithium carbonate and a sodium sulphate mother liquor.</p> |
