Abstract: An improved batch process for the production, in equipment readily available at the fertilizer dealer level, of high-analysis stable ammonium orthophosphate suspension fertilizers effected by the ammoniation of solid intermediates derived from wet-process orthophosphoric acids or combinations of the solid intermediates with such wet-process type acid or other impure phosphoric acids. Fluorosilicic acid, a by-product of the phosphate industry which is readily available and relatively inexpensive, is utilized as a source of fluoride. The fluorosilicic acid is added to the batch formulation prior to the ammoniation step thereby allowing the fluorosilicic acid to be converted to ammonium fluoride. Subsequently, the metallic impurities are allowed to precipitate as fluoride compounds instead of the usual troublesome impurity-phosphate-water gels which have been identified as causing complete destruction of suspension fluidity during storage.

Abstract: A two-stage continuous crystallization process for production of urea phosphate by reaction of impure wet-process orthophosphoric acid (about 54 percent P.sub.2 O.sub.5) and urea with simultaneous addition of a selected acidifying agent (sulfuric acid, hydrochloric acid, or phosphoric acid) to clarified mother liquor used as recycle in the process. Addition of the acidifying agent decreases pH in the crystallization process whereby the solubility of a contaminating water-insoluble iron phosphate-urea salt [FeH.sub.3 (PO.sub.4).sub.2.2CO(NH.sub.2).sub.2 ] is increased, purity of the crystalline urea phosphate product is improved significantly, and the useful storage life of the recycle mother liquor is prolonged.

Abstract: The concentration of impurities in wet-process phosphoric acid limits the usefulness of the acid for the production of fertilizers, feedgrade phosphate and detergents. The aluminum, magnesium, and fluoride impurities are removed with the calcium sulfate hemihydrate filter cake by hydrolyzing and recycling the off-gas scrubber solutions in the presence of a ferric iron catalyst. The aluminum and magnesium are reduced to less than 0.1 percent in the acid product by the precipitation of (Ca,Mg)Al.sub.2 F.sub.8 .multidot.2H.sub.2 O, which is acid insoluble and suitable for storage with the byproduct calcium sulfate. Ferric iron also serves as a catalyst for the simultaneous precipitation of (Na,K).sub.2 SiF.sub.6. Subsequent additions of potassium as, for example, in the teachings of Gilbert (U.S. Pat. No. 3,338,675), can then be applied to obtain a purified phosphoric acid product suitable for most commercial applications.

Abstract: The concentration of impurities in wet-process phosphoric acid limits the usefulness of the acid for the production of fertilizers, feed-grade phosphate and detergents. The aluminum, magnesium, and fluoride impurities are removed with the calcium sulfate hemihydrate filter cake by hydrolyzing and recycling the off-gas scrubber solutions in the presence of a ferric iron catalyst. The aluminum and magnesium are reduced to less than 0.1 percent in the acid product by the precipitation of (Ca,Mg)Al.sub.2 F.sub.8.2H.sub.2 O, which is acid insoluble and suitable for storage with the byproduct calcium sulfate. Ferric iron also serves as a catalyst for the simultaneous precipitation of (Na,K).sub.2 SiF.sub.6. Subsequent additions of potassium as, for example, in the teachings of Gilbert (U.S. Pat. No. 3,338,675), can then be applied to obtain a purified phosphoric acid product suitable for most commercial applications. The added potassium serves two purposes in the 40 to 55 percent P.sub.2 O.sub.

Abstract: A two-stage continuous crystallization process for production of urea phosphate by reaction of impure wet-process orthophosphoric acid (about 54 percent P.sub.2 O.sub.5) and urea with simultaneous addition of a selected acidifying agent (sulfuric acid, hydrochloric acid, or phosphoric acid) to clarified mother liquor used as recycle in the process. Addition of the acidifying agent decreases pH in the crystallization process whereby the solubility of a contaminating water-insoluble iron phosphate-urea salt [FeH.sub.3 (PO.sub.4).sub.2.2CO(NH.sub.2).sub.2 ] is increased, purity of the crystalline urea phosphate product is improved significantly, and the useful storage life of the recycle mother liquor is prolonged.