| 摘要 |
<p>A continuous process for removing nitrates from nitrate containing aqueous solutions having a pH of about 0-7, which comprises: (1) extracting the nitrate containing aqueous solution with an organic amine salt dissolved in an organic solvent phase whereby the nitrate ion goes into the organic solvent, (2) separating the organic phase, (3) stripping the organic extraction solvent phase from the extraction with a stripping salt solution of pH at least 0.5, said salt being capable of ion exchange with the nitrate ion and containing the anion of the amine salt in step (1) to strip and convert the amine for the next extraction cycle into the same amine salt as used for the extraction; and the stripping solution contains the nitrate ion and the cation of the stripping solution; (4) maintaining the concentration of the salt formed by the cation of the stripping salt and the nitrate anion in the stripping solution so high that this salt is crystallized from the stripping solution substantially continuously, but still so low that the nitrate anion extracted into the organic extraction solvent phase passes during the stripping continuously into the stripping solution while the anion of the stripping salt passes from the stripping solution into the organic extraction solvent phase; and recovering crystallized nitrate salt from the stripping solution.</p> |
