GB571080A - Improvements in and relating to mixed fertilisers - Google Patents

Abstract

571,080. Manures. ETTLE, G. W., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. July 21, 1943, No. 11842. [Class 111] A mixed fertilizer, which remains substantially dry in storage and is capable of being easily spread, comprises two or more ingredients and powdered calcined gypsum (i.e. calcium sulphate hemihydrate, soluble anhydrite, and any intermediate hydrated calcium sulphate) or accelerated anhydrous calcium sulphate plaster, in which sulphates or acid sulphates of alkali metals or ammonium, cupric, zinc, ferrous, ferric or aluminium sulphates or their double sulphates are used as accelerators of hydration, as described in Specifications 236,695, 317,672, [both in Class 22,], 459,134 and 554,952, [both in Group V], 2-10 per cent. of the calcined gypsum (e.g. plaster of Paris) or the accelerated plaster may be used, preferably 5-10 per cent. with finely divided fertilizers and 3-6 per cent. with granular fertilizers. The anti-caking agent may be incorporated with one or each of the dry ingredients before mixing, or with the final mixture, and is preferably mixed in well so that it coats the particles of the fertilizer. The fertilizers to which the invention is applied may comprise ammoniuim sulphate, ammonium phosphate, potassium sulphate, and the mixed fertilizer known by the Registered Trade Mark '` Nitro-Chalk " (ammonium nitrate and calcium carbonate). The Provisional Specification refers to providing water in the mixture to form a solid cake which is then crushed to granules and dried, and also to the use of silica gel and alumina gel to prevent caking.