GB881552A - Improvements in methods of coating seeds - Google Patents

Abstract

881,552. Seed pellets. COMPAGNIE NORDAFRICAINE DE L'HYPERPHOSPHATE RENO. July 29, 1959 [Aug. 9, 1958], No. 26062/59. Class 58. To assist germination of seeds such as wheat, rice and maize, they are wetted with water or an aqueous wetting solution and coated with a powdered fertilizer, e.g. whose particles have passed through a screen having 80 to 100 meshes per square inch, to form pellets, which are then sprayed with concentrated sulphuric acid or ammonia to initiate drying by the heat developed. The fertilizer may contain natural or artificial phosphates or nitrogen and potash. Diatomaceous earth or kieselguhr may be mixed with the fertilizer. The amount of fertilizer coated on the seeds may be between three and seven times their weight. Between 3 and 5% of sulphuric acid, based on the weight of the pellets, may be used. The pellets may be given an additional coating of a finely powdered fertilizer, e.g. a superphosphate fertilizer, whose particles have passed through a screen having 300 meshes per square inch. A dye identifying the kind of seed may be incorporated in this coating. Alternatively, the pellets may be sprayed with an aqueous solution of sodium silicate. For example, seeds from a shoot 8, water from one or more sprinklers 10 and powdered fertilizer from a spout 13 are fed into the central compartment 1 of the rotating inclined tray of a granulator. The central compartment is surrounded by two annular concentric compartments 2 and 3. The powdered fertilizer sticks to the wetted seeds and forms a coating around each to produce pellets. These overflow into compartment 2 wherein they are sprinkled with concentrated sulphuric acid from one or more sprinklers 14. The pellets overflow into compartment 3, in which they are coated with finely powdered fertilizer supplied through a conduit 15, and then overflow into a shoot 16 or, alternatively, a conveyer belt.