FIELD: agriculture.
SUBSTANCE: invention relates to agriculture. The method for producing dihydrophosphate, hydrophosphate and calcium phosphate as fertilizers is characterized in that a solution containing calcium nitrate or chloride, phosphoric acid, nitric or hydrochloric acid is subjected to heating and boiling at t=50-150°C, adding a volume of distilled water with stirring , equal to the volume of the evaporated solution, or first evaporate a solution containing calcium nitrate or chloride, phosphoric acid, nitric or hydrochloric acid until a mixture of wet salts is formed, and then the resulting mixture of wet salts is heated at t=100-200°C, or a solution containing calcium nitrate or chloride, phosphoric acid, nitric or hydrochloric acid is evaporated by heating until a mixture of wet salts is formed, and then this mixture is heated until dry salts are formed, which are then heated-calcined at t=150-600°C, at the same time, vapors of nitric or hydrochloric acid, together with water vapor, are distilled off and condensed to obtain a solution of nitric or hydrochloric acid, which is reused, and the residue remaining after distillation is mixed with water, and a precipitate of sparingly soluble calcium dihydrogen phosphate, poorly soluble calcium hydrogen phosphate and insoluble calcium phosphate, which is separated by filtration.
EFFECT: invention makes it possible to obtain acidic and medium calcium phosphates as fertilizers, as well as to significantly reduce the consumption of hydrochloric or nitric acid.
2 cl, 4 ex
