GB424260A - Improvements in the manufacture and production of fertilisers - Google Patents

Abstract

A carbonaceous fertilizer is prepared by treating a mixture of crude phosphate and solid carbonaceous substances of vegetable origin, in the presence of small quantities of water, with gases comprising oxides or hydrated oxides of nitrogen of at least the tetroxide stage, and then neutralizing the resulting mass with p basic substances. The carbonaceous substances referred to are coal, lignites, peat, lignin and wood in the form of saw-dust. The gaseous oxides of nitrogen &c., referred to are nitrogen tetroxide which may be employed in the nascent state by using a mixture of nitric oxide and oxygen, e.g. ammonia combustion gases, nitric acid, and gases obtained by decomposing nitrosyl chloride with oxygen. The neutralization may be effected with gaseous, liquid or aqueous ammonia, ammonium salts such as the carbonate or bicarbonate, potassium, sodium or calcium carbonate, and lime. Further fertilizing substances such as potassium compounds with or without inorganic adsorbents, e.g. silica gel, alumina gel, zeolites, blast furnace slags or slags from the electrothermic manufacture of phosphorus may be added before, during or after the treatment with oxides of nitrogen or the like. If necessary, the phosphate may be pretreated with a little mineral acid in order to decompose fluorine compounds. The Provisional Specification is not restricted to the employment of the nitrogen oxides &c., in the gaseous form.