Albright & Wilson Limited

Robert Harry Edwards

Thomas A Williams

Kenneth Hall

When crude wet process phosphoric acid is solvent extracted, an aqueous raffinate containing phosphoric acid and a small amount of solvent is produced as a by-product. Certain materials are added to the raffinate, in order to produce two phases, one aqueous and the other of solvent. The phases are separated, the solvent recycled for reuse in a solvent extraction process and the aqueous phase treated with ammonia or alkali or alkaline earth metal compounds to form a fertilizer or other phosphate salt.

Process for removing solvent from the raffinate of extracted phosphoric

A solid anhydrous crystalline compound of the formula H.sub.3 PO.sub.4 [(CH.sub.3).sub.2 CH].sub.2 O. The invention also provides a method of preparing phosphoric acid by evaporating diisopropyl ether off said anhydrous crystalline compound under reduced pressure.

Ether phosphoric acid compound

A solid anhydrous 1:1 molar compound of phosphoric acid and diisopropyl ether is prepared from a mixture of the ether and phosphoric acid in a molar ratio (R:1) of 0.6:1 to 1.4:1 at a temperature at least as low as the crystallization temperature (T.degree.C) governed by the relationship T = 25(1.2-R). Treatment of the compound with water or a base produces purified acid or a phosphate respectively.

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Whitehaven, United Kingdom

Robert Harry Edwards