| 摘要 |
<p>PURPOSE:In refluxing a supernatant liquid of an extracted solution and/or a filtrate of an insoluble residue to an extraction tank having a small ratio of extracted solution/slag, to improve the yield of recovery of Na2O and to prevent the bad influence on the operations of process, by controlling the specific gravity of the extracted solution. CONSTITUTION:A ratio of water in the extraction tank 1, namely, a ratio of circulate solution/slag is made small to about 1.5-4, and a supernatant liquid of an extracted solution in the thickener 4 and/or a filtrate of an insoluble residue separation of the separator 5 are partially refluxed to the tank 1. An apparent ratio of a refluxed solution + the circulated solution to slag is made >=4 so that the extracted solution is stirred smoothly. The relationship between the density, pH, and temperature of the extracted solution, the circulated solution, is obtained, and the density is controlled in a fixed range, so that the concentration of Na2O of the extracted solution is maintained at a constant value. When the set value of the concentration is too much close to the density of a saturated solution, the extraction ratio of Na is lowered and when it is too small, the crystallization ratio of Na is reduced.</p> |
