A process for the extraction of phosphoric acid by amyl alcohol

Abstract

A process describes an efficient and economical route for the preparation of phosphoric acid by treating rock phosphate with commercial hydrochloric acid which is a cheap by-product of the soda ash industries followed by its separation from the crude mixture by solvent extraction using amyl alcohol as solvent to remove impurities up to a great extent and yields phosphoric acid of good quality which easily concentrates. The recovery of the amyl alcohol from different stages of the process is found to be convenient due to its low water miscibility, and its re-extraction efficiency is comparable to that of fresh solvent, the alcohol easily recover from the raffinate phase by vacuum distillation at 110 °C. Maximum phosphorous pentaoxide (P2O5) is recovered when an acid-rock ratio is 1 :1.2 w / v and acid / alcohol ratio is kept at 1:2 and extraction efficiency reaches a maximum of 65%. The addition of small amounts of acetaldehyde increases the extraction efficiency from 41 to 65%. The acid, obtained by this metho is of high quality and could be upgraded up to density of 1.5 g / mL at 25 °C, it is an efficient and economical method.