| 摘要 |
Process of sodium oxalate purification of sodium aluminate solutions resulting from alkaline attack of bauxites according to the Bayer process, comprising: precipitation of said sodium oxalate in at least a fraction of the pre-decomposed sodium aluminate solution, by means of an agent that destabilizes the supersaturation state of the sodium oxalate, or deoxalation initiator, separation of the oxalate, precipitated with the destabilizing agent in the form of an insoluble residue, and the purified sodium aluminate solution which is then recycled as the leaching liquor, characterized in that the destabilizing agent or deoxalation initiator, placed in contact with the sodium aluminate solution, is a salt other than an oxalate, a metal oxide, a metal hydroxide, or a mixture thereof, said destabilizing agent remaining insoluble and chemically inert with respect to the reaction medium, and in that, after regeneration if any, it is recycled to the top of the process as the deoxalation initiator. |
