GB405504A - Process of manufacturing fertilizers from raw phosphate - Google Patents

Abstract

For the production of a fertilizer consisting principally of monocalcium phosphate, and ammonium or potassium and calcium nitrates, ground raw phosphate is mixed with solid ammonium or potassium trinitrate. The trinitrate may be added all at once or in successive portions. At most half of the trinitrate may be replaced by nitric or phosphoric acid or both, a suitable form of nitric acid being that present in the mother liquor obtained in producing the trinitrate, suitably according to the method disclosed in Specification 403,289. So much water may be added before, during or after mixing that the monocalcium phosphate formed will contain one molecule of water. Other substances such as those containing phosphorus, potassium or nitrogen, or two or more of them, may be added to the reactants before or after mixing. Monoammonium phosphate is specified. The reaction mixture may be heated, and the viscous mixture dried with stirring. Drying may be effected in an ammonia atmosphere, or the mixture may be dried whilst sprinkled with an alkaline liquid. The product may be extracted, for example in the presence of ammonium sulphate. The solution of ammonium phosphate and nitrate obtained, for example, is separated from the gypsum and worked up by evaporation.