Method for manufacturing an ammonium phosphate fertilizer having low cadmium content

A method for manufacturing an ammonium phosphate fertilizer from a phosphoric acid aqueous solution that has from 25 to 45% P2O5 concentration and is obtained by wet phosphate ore treatment by sulfuric acid, said phosphoric acid containing traces of cadmium, comprising the following steps:

• (a) neutralizing said phosphoric acid solution with gaseous ammonia up to a molar ratio N/P of between 0.1 and 0.8,
• (b) reacting said partially neutralized solution with a sulfide source so as to form a cadmium sulfide precipitate,
• (c) separating said precipitate so as to obtain a refined ammoniated phosphoric acid solution,
• (d) concentrating the refined ammoniated phosphoric acid solution,
• (e) ammoniating and granulating said concentrated refined ammoniated phosphoric acid solution so as to form said fertilizer,
• all steps (a) to (e) being carried out in an ammonium phosphate fertilizer manufacturing line.