GB396092A - A process for the production of nitrogenous and/or phosphatic mixed fertilisers of desired composition by treatment of raw phosphates with nitric acid - Google Patents

Abstract

Fertilizers are prepared by decomposing raw phosphates with that quantity of nitric acid necessary to render the phosphoric acid present soluble, treating the mixture with ammonium salts of those acids which with calcium form difficulty soluble salts, preferably with ammonium sulphate, filtering off the precipitated calcium sulphate and undecomposed gangue, evaporating the solution almost to dryness to form a mixture of ammonium nitrate, ammonium phosphates and residual calcium sulphate, and treating the mass with liquid or gaseous ammonia in a practically pure state until the nitrate is dissolved out. The ammonium nitrate, after the removal of the ammonia, and the ammonium phosphate, preferably after the removal of residual ammonia, are then mixed with one another in the proportions desiredm or one or the other may be mixed with the dried reaction mass which has not been treated with ammonia. Any residual ammonium nitrate or ammonium phosphate may be mixed with other fertilizers. The ammonia used for dissolving out the ammonium nitrate, if necessary after separation from the ammonium nitrate, may be combined with acid to form fertilizers. Specifications 356,759, [Group II], and 389,082 are referred to.ALSO:Fertilizers are prepared by decomposing raw phosphates with that quantity of nitric acid necessary to render the phosphoric acid present soluble, treating the mixture with ammonium salts of those acids which with calcium form difficulty soluble salts, preferably with ammonium sulphate, filtering off the precipitated calcium sulphate and undecomposed gangue, evaporating the solution almost to dryness to form a mixture of ammonium nitrate, ammonium phosphates and residual calcium sulphate, and treating the mass with liquid or gaseous ammonia in a practically pure state until the nitrate is dissolved out. The ammonium nitrate, after the removal of the ammonia, and the ammonium phosphate, preferably after the removal of residual ammonia, are then mixed with one another in the proportions desired, or one or the other may be mixed with the dried reaction mass which has not been treated with ammonia. Any residual ammonium nitrate or ammonium phosphate may be mixed with other fertilizers. The ammonia used for dissolving out the ammonium nitrate, if necessary after separation from the ammonium nitrate, may be combined with acid to form fertilizers. Specifications 356,759, [Group II], and 389,082 are referred to.