GB358637A - Process for the manufacture of magnesium ammonium phosphates poor in water contents - Google Patents

Abstract

In a modification of the process of the parent Specification gaseous ammonia is added to a mixture of phosphoric acid or alkali phosphate such as potassium phosphate, and magnesium salts such as the nitrate, chloride or sulphate, or potassium waste liquor, or magnesium oxide or hydroxide, whereby crystalline magnesium-ammonium phosphate is obtained. The ammonia gas may react on the mixture either in solution or suspension, or in the solid state. In the former case, after separation of the double salt, the liquors may be treated with lime for the recovery of p ammonia, this step, however, being unnecessary where magnesium oxide is used. Alternatively the ammonium salts may be crystallized. When an alkali phosphate is employed, the corresponding alkali salts, say, potassium nitrate, may be crystallized, separately, or with the ammonium salts, for use as a fertilizer. If, however, magnesium ammonium phosphate is not separated, these salts may be crystallized thereon. In the case where the reactants in the solid state are treated with gaseous ammonia, a solid manure containing magnesium, nitrogen, phosphorus and sometimes potassium is obtained. Other manures may be added prior to or subsequent to the reaction.ALSO:In a modification of the process of the parent. Specification gaseous ammonia is added to a mixture of phosphoric acid or alkali phosphate such as potassium phosphate, and magnesium salts such as the nitrate, chloride or sulphate, or potassium waste liquor, or magnesium oxide or hydroxide, whereby magnesium ammonium phosphate is obtained. The ammonia gas may react on the mixture in solution or suspension, or in the solid state. In the former case, the double salt may be separated, and a mixture of alkali and ammonium salts crystallized. If, however, magnesium ammonium phosphate is not separated, these salts may be crystallized thereon. In the case when the reactants are treated in the solid state with gaseous ammonia, a solid manure containing magnesium, nitrogen, phosphorus and sometimes potassium is obtained. Other manures may be added prior to or subsequent to the reaction.