PROCESS OF MANUFACTURING NITROGEN-PHOSPHORUS-SULFATE FERTILIZERS Russian patent published in 2008 - IPC C05B11/04 C05G1/06 C05C1/00 

FIELD: mineral fertilizers.

SUBSTANCE: invention relates to manufacturing ammonium nitrate-based complex fertilizers. Process of invention concerning, in particular, manufacture of nitrogen-phosphorus-sulfate fertilizer based on ammonium nitrate and product of acid decomposition of apatite concentrate containing up to 8% P₂O₅ is characterized by decomposing above concentrate with nitric and sulfuric acids followed by neutralization, mixing of liquid and solid decomposition products with ammonium nitrate, and granulation of target product, wherein acid decomposition products, before neutralization and mixing with ammonium nitrate, are separated, after which liquid decomposition products are mixed with ammonium nitrate and evaporated to anhydrous melt state. The latter is then mixed with thermally treated solid decomposition products, wherein calcium sulfate is present in the form of semihydrate. Target product is granulated using prilling technique. Invention is further characterized by that acid decomposition products, prior to be separated, are additionally treated with ammonium sulfate while maintaining summary sulfate ion uptake (in the form of sulfuric acid and ammonium sulfate) equal to 110-120% based on stoichiometric amount of calcium in apatite concentrate. Uptake of ammonium nitrate upon mixing is maintained between 3 and 9 t per 1 t apatite concentrate to be decomposed with nitric and sulfuric acids.

EFFECT: achieved presence of phosphorus in fertilizer only in water-soluble form, increased strength of granules, and enabled implementation of the process under large-scale conditions on modern technological equipment.

3 cl, 2 ex