METHOD FOR PRODUCTION OF COMPLEX NITROGEN-PHOSPHOROUS FERTILIZER Russian patent published in 2005 - IPC

FIELD: chemical industry, agriculture.

SUBSTANCE: invention relates to method for production of double NP-fertilizer containing 3-7 mass % of P₂O₅ from concentrated ammonium nitrate solution and extractive phosphoric acid solution. Starting phosphoric acid (52-54 %) is diluted with weak ammonium nitrate solution, diluted solution is additionally treated with ammonium nitrate to produce NH₄NO₃:P₂O₅ ratio in ammoniated solution not less than 3:1, wherein ammoniating is carried out simultaneously with auxiliary treatment or thereafter. Ammoniated solution is boiled down to produce residual water content of 5-20 mass % and mixed with concentrated ammonium nitrate solution. Then obtained solution is finally neutralized with ammonia, boiled down and grained. Phosphorous content in ammoniated solution is maintained preferably from 4 to 10 mass % calculated as P₂O₅, and as ammonium nitrate in auxiliary treatment of diluted solution preferably concentrated ammonium nitrate solution obtained by nitric acid neutralization with ammonia or 40-50 % solution obtained by conversion of calcium nitrate with ammonium carbonate is used.

EFFECT: simplified method for production of complex nitrogen-phosphorous fertilizer.

5 cl, 3 ex