| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for the purification or recovery of orthophosphoric acid rich streams by suspension-based melt crystallization. SOLUTION: The orthophosphoric acid is crystallized as the hemi-hydrate form and subsequent separation of such crystals in a wash-column produces a high purity acid/water solution that has been deleted of most of the metals and impurities other than water, thereby separating an orthophosphoric acid rich feed liquor into an ultra-pure orthophosphoric acid hemi-hydrate and a mother liquor containing almost all impurities originally present in the feed. The orthophosphoric acid rich feed liquor typically contains≤15 mass% water and≤1 mass% other impurities. Individual metal ion composition in the purified orthophosphoric acid product is in the range of 100-1,000 ppb of each metal ion. The metal ion composition of the resulting purified product is thus typically below the detection limit of typical analysis equipment. COPYRIGHT: (C)2009,JPO&INPIT
|
