Abstract: Improved solvent systems for the formulation of N-alkyl thiophosphoric triamide urease inhibitors. These formulations enable the preparation of stable concentrated solutions of N-alkyl thiophosphoric triamides for storage, transportation, and eventual impregnation onto solid urea containing fertilizers and incorporation into liquid urea containing fertilizer compositions. These formulations are comprised primarily of a solvent selected from the group consisting of glycols and glycol derivatives. Optionally, in addition to the glycol base solvent, the formulations can contain a co-solvent selected from the group consisting of liquid amides, 2-pyrrolidone and N-alkyl 2-pyrrolidones, and/or a nonionic surfactant selected from the group consisting of alkylaryl polyether alcohols. The presence of the co-solvent and/or surfactant has been found to impart desirable properties to the formulations under certain conditions.

Abstract: An improved fluid urea-containing fertilizer composition is disclosed; the composition is essentially comprised of an aqueous solution of urea, ammonium nitrate, N-(n-butyl)thiophosphoric triamide (NBPT), dicyandiamide (DCD), and may optionally also contain a clay as a suspending agent. The fluid fertilizer composition can be applied to a field crop in a single application and will nevertheless supply sufficient nitrogen to the plants throughout their growth and maturing cycles. As a result, the improved composition increases the nitrogen uptake efficiency of plants, enhances crop yields, and minimizes the loss of nitrogen from the soil.

Abstract: An improved homogenous granular fertilizer composition is disclosed; the composition is comprised primarily of urea, N-(n-butyl)thiophosphoric triamide (NBPT), and dicyandiamide (DCD). The composition of this invention can be applied to a field crop in a single surface application and will nevertheless supply sufficient nitrogen to the plants throughout their growth and maturing cycles. The new improved composition increases the nitrogen uptake by plants, enhances crop yields, and minimizes the loss of both ammonium nitrogen and nitrate nitrogen from the soil.The NBPT is incorporated into the homogenous granular fertilizer composition of this invention by blending a concentrated solution of NBPT in a solvent selected from the group consisting of liquid amides, 2-pyrrolidone, and N-alkyl 2-pyrrolidones directly into molten urea prior to its granulation; the DCD may be added to the urea melt as a solid or in dissolved form along with the NBPT.

Abstract: Stabilized phosphogypsum-containing compositions with low expansion and high compressive strength characteristics are prepared by admixing phosphogypsum with a cementitious binder having a calculated zero percent tricalcium aluminate content The compositions may contain phosphogypsum and cementitious binder only or they may also include sand or other filler material. The phosphogypsum composition is wetted with water, compacted and allowed to cure. The amount of water added preferably produces a maximum density of the compacted composition.

Abstract: A process for producing high grade silica and fluorine-containing coproducts from fluosilicic acid is described. To produce silica, the fluosilicic acid is reacted with aqueous ammonia to produce a solid silica product and a solution of ammonium fluoride. The solid silica is washed under controlled conditions and further processed to produce a high grade product. The ammonium fluoride solution is concentrated and sold as a concentrated ammonium fluoride solution product or reacted with metal hydoxides or oxides to produce metal fluorides.

Abstract: Process for the recovery of uranium from wet process phosphoric acid solution in which an organic extractant, containing uranium values and dissolved iron impurities and comprising a dialkylphosphoric acid and a trialkylphosphine oxide dissolved in a water immiscible organic solvent, is contacted with a substantially iron-free dilute aqueous phosphoric acid to remove said iron impurities. The removed impurities are bled from the system by feeding the resulting iron-loaded phosphoric acid to a secondary countercurrent uranium extraction operation from which they leave as part of the uranium-depleted acid raffinate. Also, process for recovering uranium in which the extractant, after it has been stripped of uranium values by aqueous ammonium carbonate, is contacted with a dilute aqueous acid selected from the group consisting of H.sub.2 SO.sub.4, HCl, HNO.sub.3 and iron-free H.sub.3 PO.sub.4 to improve the extraction efficiency of the organic extractant.