Redn. of trivalent iron in wet-process phosphoric acid - by adding phosphorus sub-oxide as reducing agent

摘要

A process for the redn. of Fe ions from the 3+ to the 2+ oxidn. states in wet process phosphoric acid and with the aid of a reducing agent comprises using as reducing agent a suboxide of P of formula POx (I), where x is 1.0-1.5. A high Fe2+ content is necessary in the work up and purification of wet process phosphoric acid. Fe2+ ions are used in the removal of V from the phosphoric acid, and in the redn. of U (VI) to U (IV). PO x possesses a high reducing power and does not add any substances which would contaminate the phosphoric acid, or reduce yields. POx is also stable in the atmosphere and is a solid which is easily added and is safe and easy to handle.