GB1195332A - Fertilizers - Google Patents

Abstract

1,195,332. Fertilizers. FISONS FERTILIZERS Ltd. 26 Nov., 1968 [13 Jan., 1968], No. 2022/68. Heading C1B. A granular NPK fertilizer comprises ammonium phosphate nitrate and potassium metaphosphate of formula (KPO 3 ) n or (KPO 3 ) n .M where n is 10-200 and M is an inorganic compound present to control the value of n. M may be calcium chloride, ferric oxide, calcium oxide, magnesium oxide, silica, or phosphate rock. Other fertilizer constituents may be ammonium sulphate, potassium chloride, potassium sulphate, calcium phosphate, urea, magnesium sulphate, boron, zinc, copper, manganese, cobalt, iron, calcium carbonate, and sand. 10-90% of ammonium phosphate nitrate, 10-90% of potassium metaphosphate, and 0-15% of other constituents may be present. Granulation may be effected by (a) compressing or extruding a mixture of ammonium phosphate nitrate and potassium metaphosphate to form a sheet and breaking into granules, (b) spraying molten ammonium phosphate nitrate on to tumbled potassium metaphosphate at 90-125‹ C. in the presence of water, (c) forming a dispersion of potassium metaphosphate in molten ammonium phosphate nitrate, cooling on a cold surface and flaking, (d) forming a dispersion of potassium metaphosphate in molten ammonium metaphosphate and prilling, or (e) prilling molten ammonium phosphate nitrate in the presence of dust comprising potassium metaphosphate. Prilling may be effected in a cooling liquid, gas or dispersed or fluidized dust. The dust may comprise potassium metaphosphate, limestone, sand, sulphur, talc, clay, or a magnesium compound. The product may be coated with talc or kieselguhr to prevent caking.