High-analysis acid-type fertilizer solutions

Abstract

Unusually high-analysis low-temperature-stable solution-type fertilizers are produced by mixing urea and phosphoric acid with urea-ammonium nitrate solution (UAN). The ratio of P.sub.2 O.sub.5 to total nitrogen and the ratio of CO(NH.sub.2).sub.2 --N(nitrogen) to NH.sub.4 NO.sub.3 --N(nitrogen) must be maintained within broad specified parameters in order to ensure the production of the instant high-analysis clear-liquid fertilizers which are stable at temperatures as low as 0.degree. C. For example, to produce a 35 percent total plant nutrient (TPN) product, the weight ratio for P.sub.2 O.sub.5 :N (total) must be within the range of about 0.316 to about 0.538, the weight ratio of urea-N to NH.sub.4 NO.sub.3 --N+P.sub.2 O.sub.5 must be in the rang of 1.41 to 1.59, and the weight ratio of CO(NH.sub.2).sub.2 :NH.sub.4 NO.sub.3 must be in the range of 15.25 to 3.75. Similar solutions may be produced by dissolving solid urea and ammonium nitrate in pure or impure phosphoric acid or by utilizing urea.H.sub.3 PO.sub.4 obtained from impure wet-process type phosphoric acid or by mixing the urea phosphate with UAN. The pH of the resulting product solutions ranges from 2.0 at P.sub.2 O.sub.5 :N (total) of 0.33 to a pH of 1.6 when the P.sub.2 O.sub.5 :N (total) is 0.5.