GB989761A - Granulators - Google Patents

Abstract

In a process for.making fertilizer granules of ammonium phosphate, ammonium nitrate and potassium chloride the granulator comprises drums 41, 42 and 43, rotatable about horizontal axes at the same horizontal level, through which the solid material circulates in a cyclic path. Solid material is raised by buckets 44 from the tumbling beds of each drum and delivered to the proximate end of the succeeding <PICT:0989761/C1/1> drum. Potassium chloride is added to shoot 46 between drums 41 and 42, ammonia is led below the surface of the tumbling bed in drum 42 through pipe 47 and pipe 48 leads phosphoric acid on to or below the bed. In drums 41 and 43 pipes 49 and 50 respectively lead ammonia and nitric acid below the surfaces of the tumbling beds. The shoot 46 between drums 43 and 41 is fitted with a product offtake 51 leading to conveyer 52. Material removed from the circulating stream is screened to obtain a product in the desired size range, the fines obtained together with the crushed oversize being returned to the stream together with the potassium chloride on shoot 54. The exit of each drum is provided with an exhaust duct 53. Means, not shown, are provided for the application of heat either direct to the outside of the drums, or indirectly by the passage of warm gases through the drums. The rate of delivery by the shoot 46 may be improved by pneumatic or vibrational assistance. The drums may be in the form of apparatus described in Specifications 963,160, 950,755 and 907,900.