GB282330A - Method of producing mixed manures - Google Patents

Abstract

282,330. Liljenroth, F. G. Dec. 14, 1926, [Convention date]. Manures.-Crude calcium phosphate is leached with nitric acid, which may be in excess, and calcium sulphate is precipitated by the simultaneous or subsequent addition of ammonium sulphate to the acid solution, which is then filtered, neutralized with ammonia, and evaporated, to form a manure. By reacting on the calcium sulphate with ammonia and carbon dioxide, ammonium sulphate and calcium carbonate are formed. The carbon dioxide is regenerated from the latter by heating it or by treatment with an acid. A little sulphuric acid may be used in the leaching acid. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the use of other acids having soluble calcium salts, e.g. hydrochloric acid as leaching acid, and the addition of one or more alkali metal sulphates, e.g. sodium or potassium sulphate or bisulphate to the solution. Other bases than ammonia vielding soluble phosphates may be used for neutralization. The calcium sulphate may be heated to give sulphur dioxide which is converted into sulphuric acid and used to prepare the required alkali sulphate. By adding potassium compounds, preferably the chloride, or by adding an excess of soluble sulphate, these compounds and ammonium nitrate remain in the manure. This subject-matter does not appear in the Specification as accepted.