| 摘要 |
In one aspect, the invention includes a method of purifying phosphoric acid comprising filtering a feed solution of phosphoric acid through a membrane, wherein the feed solution is maintained at a temperature of from about 30 DEG F. to about 90 DEG F. during the filtering. In another aspect, the invention includes a method of purifying phosphoric acid comprising: a) providing a feed solution of phosphoric acid, said feed solution comprising greater than 17,000 ppm on a 100% P2O5 basis of each of Al, Fe and Mg; and b) filtering the feed solution through a polyamide filter configured for nanofiltration, the filtering comprising a temperature of from about 30 DEG F. to 90 DEG F., and a pressure of from about 600 psig to about 1000 psig to form a purified phosphoric acid solution, the purified phosphoric acid solution comprising less than 1700 ppm on a 100% P2O5 basis of each of Al, Fe and Mg.
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