Apparatus for coating particulate material with finely divided solids

An apparatus for uniformly coating a granular fertilizer with a small amount of a finely divided nutrient material having an average bulk density above about 1.2 g./ml. selected from the group consisting of micronutrients, secondary nutrients and mixtures thereof comprising, in combination:

• a. a hopper for storing granular fertilizer;
• b. a control gate adapted to produce a metered flow of fertilizer from said hopper in the form of a falling curtain;
• c. a storage vessel adapted to contain a binder solution;
• d. nozzles disposed so as to provide spray of said binder solution below said gate, at opposite sides of said curtain so as to produce uniformly sprayed granular fertilizer;
• e. conduits adapted with valve means so as to convey the binder solution at a desired pressure from said storage vessel to said nozzles;
• f. a mixing chamber comprising a tumbling drum adapted to blend said sprayed fertilizer with said nutrient material;
• g. a conveyor adapted so as to receive said sprayed granular fertilizer below said nozzles and to convey the fertilizer received into and from said tumbling drum;
• h. a blow case equipped with a pressurizing means adapted to receive said nutrient material;
• and
• i. a conduit adapted to inject said nutrient material into said tumbling drum under superatmospheric pressure from said blow case to form a cloud of nutrient material after said chamber is sealed with the sprayed granular fertilizer.