COMPLEX SULFUR-CONTAINING FERTILIZER MANUFACTURING PROCESS Russian patent published in 2008 - IPC C05B11/04 C05G1/06 

FIELD: mineral fertilizers.

SUBSTANCE: invention relates to technology of manufacturing ammonium nitrate-based complex fertilizers, in particular to sulfur-containing fertilizer based on ammonium nitrate and products of acid decomposition of apatite concentrate with weight ratio N/P₂O₅ more than 2:1. Apatite concentrate is decomposed under conditions of calcium-based stoichiometric excess of hydrogen ions in apatite concentrate using nitric acid and sulfate-containing reagent, after which products of acid decomposition of apatite concentrate are neutralized by mixing them with ammonium nitrate and supplemented, if necessary, by potassium salt. Products are then granulated and dried. Above-mentioned sulfate-containing reagent is, in particular, sulfuric acid and ammonium sulfate at summary consumption of sulfate ion within a range of 75 to 115% related to calcium-based stoichiometry and molar ratio of (NH₄)₂SO₄/H₂SO₄ at least 0.3:1 and molar ratio HNO₃/H₂SO₄ at least 2.7:1.

EFFECT: reduced abrasion of granules.

4 cl, 1 tbl, 6 ex