Acid type solid urea-nitric fertilizer
AssigneeTennessee Valley Authority
InventorsJack M. Sullivan, Yong K. Kim, Kjell R. Waerstad
Life of this patent
Estimating the term…
Abstract
The present invention relates to the reaction of phosphate rock with nitric acid and urea to produce nitrogen-phosphorus containing slurries, which slurries, in turn, may be granulated and dried to produce solid N-P fertilizer products with agronomically advantageous low pHs (1.0-4.0). The products have excellent storage characteristics. The improved properties of these products result partially from the formation of a new compound, Ca(H.sub.2 PO.sub.4)(NO.sub.3).CO(NH.sub.2).sub.2, which was discovered during the course of the investigation that led to the instant invention.
Claims17
A new composition of matter having the molecular formula, Ca(H.sub.2 PO.sub.4)(NO.sub.3).CO(NH.sub.2).sub.2, and having the following x-ray powder diffraction pattern:
- ______________________________________ d, .ANG. I/Io d, .ANG. I/Io ______________________________________ 12.45 100 2.319 7 5.12 18 2.178 7 4.73 12 2.078 3 4.63 8 2.071 3 4.61 5 1.991 1 4.135 9 1.971 2 3.914 20 1.922 3 3.902 35 1.829 1 3.875 40 1.790 2 3.214 27 1.775 4 3.170 16 1.691 3 3.140 45 1.568 2 3.105 20 1.460 1 2.915 3 1.397 1 2.844 19 1.281 1 2.720 2 1.273 <1 2.644 14 1.242 <1 2.558 2 1.217 1 2.505 11 ______________________________________
A method for the preparation of solid urea nitric phosphate fertilizer products having agronomically advantageous low pHs ranging from about 1 to about 4 and having enhanced storage characteristics including high critical relative humidity, which process comprises the steps of:
- (1) introducing into a reactor nitric acid and finely divided particulate phosphate rock in proportions such that the mole ratio of HNO.sub.3 :CaO introduced and maintained in said reactor ranges from about 1.2 to about 2.1;
- (2) maintaining the materials introduced into said reactor for a period of time ranging from about 30 minutes to about 2 hours at temperatures ranging between about 60.degree. C. and about 100.degree. C.;
- (3) subsequently introducing into said reactor urea in proportions such that the mole ratio of urea:CaO in said reactor is adjusted to the range of between about 1.6 to about 4;
- (4) maintaining the resulting materials in said reactor for a period of time ranging between about 1 and about 2 hours and at a temperature ranging from about 30.degree. C. to about 70.degree. C.;
- and
- (5) removing from said reactor the resulting urea nitric phosphate slurry to granulating, drying and sizing steps, respectively, wherefrom said sizing step is recovered onsize particulate urea nitric phosphate;
- said product urea nitric phosphate characterized by the fact that the critical relative humidity thereof ranges upwards to about 60 percent, and the P.sub.2 O.sub.5 water solubility thereof ranges upwards from about 70 percent.
Dependencies are inferred from the claim text.