METHOD OF PRODUCING GRANULAR FERTILIZER BASED ON LIMESTONE Russian patent published in 2025 - IPC C05D3/02 C05G5/12 

FIELD: agriculture.

SUBSTANCE: invention relates to agriculture, namely to technology of producing mineral granular fertilizer based on limestone. Method of producing granulated fertilizer involves preparation of a dry mixture of limestone flour with fraction of 300-800 mcm in amount of 85-87% of the weight of the prepared fertilizer and tripoli with fraction of 80-100 mcm in amount of 13-15% of the weight of the prepared fertilizer, moistening the dry mixture with an aqueous solution of superphosphate to moisture content of 10-15%, granulating the moistened mixture in successively installed screw and dish-shaped apparatus, dusting the raw granules, their drying in a counterflow drying drum at temperature of 135-150 °C, separation by granulometric composition in vibrating screen. After separation, standard granules with fraction of 2-5 mm and substandard granules with fraction of less than 2 mm and more than 5 mm are distributed in three weighing bins and the mass of accumulated standard and substandard granules is controlled in time. If the mass of the accumulated substandard granules is less than 2 mm is more than 10% of the mass of the standard granules, the content of tripoli in the dry mixture is increased to 16-18%, and the content of limestone flour is reduced to 82-84%. If the mass of the accumulated substandard granules more than 5 mm is more than 10% of the mass of the standard granules, then the content of tripoli in the dry mixture is reduced to 10-12%, while the content of limestone flour is increased to 88-90%. After accumulation of the required amount, the off-grade granules are ground in a vertical ring mill to fraction of 80-100 mcm and, together with the recovered dust from the flue gas cleaning system, are used in amount of 15-18% of the weight of the prepared fertilizer for powdering the raw granules. At the initial stage of preparing the fertilizer, a dry mixture of limestone flour and tripoli is used for granulation in amount of 19-21% of the total weight of the prepared fertilizer.

EFFECT: increase of strength, water resistance and agrochemical efficiency of granulated fertilizers, with prolonged effect of moisture retention inside granules and gradual release of useful elements included into composition of fertilizer.

1 cl, 2 dwg