| 摘要 |
The disclosure relates to a process for purifying crude, concentrated wet-processed phosphoric acid. To this end, the disclosure provides: (a) for the organic solvent to be mixed with the starting product in a ratio by volume of more than 4:1 to effect the extraction in a single process step-from the crude wet-processed phosphoric acid-of a quantity of phosphoric acid necessary for 40 to 70 weight % of the P2O5 used to go into the organic phase, and for the resulting aqueous phosphoric acid raffinate to contain at most 28-32 weight % P2O5, and for the organic phosphoric acid solution to be separated from the phosphoric acid raffinate; (b) for the separated organic phosphoric acid solution to be scrubbed with a quantity of scrubbing solution corresponding at most to 5% of the volume of the phosphoric acid solution; for the scrubbing solution to be recycled into stage (a), and for purified phosphoric acid and phosphate salt solution, respectively, to be recovered in known manner from the scrubbed phosphoric acid solution; and (c) for the aqueous phosphoric acid raffinate produced in stage (a), if desired after prior removal of residual solvent therefrom, to be directly utilized or subjected to known purifying treatment. |
