| CPC C05B 19/00 (2013.01) [C05B 17/00 (2013.01); C05G 5/12 (2020.02)] | 7 Claims |
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1. A method for obtaining a granulated phosphate fertiliser which comprises the steps of:
i) granulating ground phosphate rock in a granulator, the ground phosphate rock having a particle size between 100 and 500 μm and a humidity between 1 and 2%, a natural carbon source in a ground state with a particle size between 0.1 and 1 mm and a humidity of 25 to 35%, a metabolic inducer of phosphorus-solubilising microorganisms and water to obtain a granulate;
ii) drying the granulate obtained in step i) by means of a stream of hot air progressively heated from 50° C. to 290° C., avoiding rapid evaporation of the water, with a granule outlet temperature of 50° C. to obtain a dry granulate;
iii) cooling the dry granulate by means of a stream of dry air at room temperature in the range of 20° C. to 25° C. to obtain cooled granules;
iv) sieving the cooled granules for removing non-granulated raw material and deteriorated granules to obtain granules with a particle size having an average diameter between 1.5 mm and 3.5 mm;
v) drying the granules obtained by step iv) by direct heating at a temperature of 300° C. for reducing humidity of the granulate to a maximum of 2%, with a granule outlet temperature of 40° C. to obtain a granulate;
vi) cooling the granulate obtained by step v) by means of a stream of dry air at room temperature in the range of 20° C. to 25° C.;
vii) optionally, adding 105 ucf/g of additional phosphorus-solubilising microorganisms of the genus bacillus or pseudomonas after step i); and
viii) sieving the granulate obtained by step vii) to obtain granules with an average particle size between 2 mm and 4 mm wherein the metabolic inducer of phosphorus-solubilising microorganisms is used in a proportion between 5% and 7%.
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6. A granulated phosphate fertiliser obtained according to the method according to claim 1, containing 25%-40% of total P2O5 with humic acids.
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