Tennessee Valley Authority

Jack M Sullivan

Robert J Radel

Ramiro Medina

Yong K Kim

Kjell Robt Waerstad

Ronald E Edwards

Raymond D Thrasher

John H Grinstead, Jr

A process for oxidizing aqueous elemental phosphorus containing residues (sludges) to produce orthophosphate containing slurries suitable for subsequent reaction with ammonia to produce nitrogen- and phosphorus-containing fertilizer products. It comprises reacting aqueous elemental phosphorus containing residues with certain special mixtures of concentrated nitric acid and sulfuric acid to effect the conversion of the elemental phosphorus content of the residues into mostly orthophosphoric acid and very little orthophosphorous acid with the relative ratios of orthophosphoric acid to orthophosphorous acid produced being dependent upon the weight ratio H.sub.2 SO.sub.4 :HNO.sub.3 employed in the processing. The reaction is conducted at the boiling point of the resulting aqueous reaction medium. Prior to the conversion to fertilizer products, the aqueous reaction product intermediate may be subjected to a solids separation step to remove insoluble salts of certain environmentally undesirable metals, such as, Pb, Cd, Ba, and Cr which are derived from phosphate rock via the dust component of phosphorus sludge.

Recovery of phosphates from elemental phosphorus bearing wastes

A process for producing high-analysis dicalcium phosphate containing phosphatic fertilizers and by-product calcium nitrate. It comprises reacting phosphate rock with nitric acid, followed by pyrolysis of the resulting acidulate to effect liberation of approximately one-half of the initially consumed nitric acid. Recycling of this liberated nitric acid allows production of available phosphate with approximately one-half the acid equivalents normally consumed during sulfuric acid processing. The calcium nitrate in the resulting pyrolyzate is separated from the phosphatic constituent by dissolution in water followed by filtration. Depending upon the initial HNO.sub.3 :CaO acidulation ratio, the available phosphate content of the resulting solid phosphatic fertilizers is high enough (48% P.sub.2 O.sub.5) to allow their use either for bulk blending with nitrogen and potash salts to produce complete grade fertilizers or for direct application as a phosphate nutrient. The resulting calcium nitrate stream may be processed to produce a variety of solid or fluid nitrogen fertilizer products. No 'throw away' by-products (other than possibly siliceous gangue) are produced.

Phosphatic and nitrogen fertilizers via HNO.sub.3 processing

Test show that 2,2,4,4,6,6-hexaaminocyclotriphosphazatriene, 2-phenoxy-2,4,4,6,6-pentaaminocyclotriphosphazatriene, 2,4-diphenoxy-2,4,6,6-tetraaminocyclotriphosphazatriene and 2,4,6-triphenoxy-2,4,6-triaminocyclotriphosphazatriene (also frequently called phosphonitrilic derivatives) of the formula ##STR1## are highly effective inhibitors of urease activity in agricultural soil systems wherein

Cyclotriphosphazatriene-derivatives as soil urease activity inhibitors

Tests show that 2,2,4,4,6,6-hexaaminocyclotriphosphazatriene, 2-phenoxy-2,4,4,6,6-pentaaminocyclotriphosphazatriene, 2,4-diphenoxy-2,4,6,6-tetraaminocyclotriphosphazatriene and 2,4,6-triphenoxy-2,4,6-triaminocyclotriphosphazatriene (also frequently called phosphonitrilic derivatives) of the formula ##STR1## are highly effective inhibitors of urease activity in agricultural soil systems wherein

Cyclotriphosphazatriene-derivatives

A process for the preparation of nitrogen fertilizers, especially oxamide, either indirectly or directly from oxalate esters, including the regeneration of the quinone oxidant utilized in the formation of the above esters. The process teaches preparation of oxamide, a potential slow-release nitrogen fertilizer via the oxidative carbonylation of alcohols with carbon monoxide in the presence of a catalytic amount of a platinum group metal salt and an optionally substituted quinone (substituted or unsubstituted 2,5-cyclohexadiene-1,4-dione) followed by ammoniation of the filtered reaction mixture at room temperature, or below. High yields of isolated oxamide were obtained by regulating the temperature and pressure during the oxidative carbonylation and maintaining essentially anhydrous conditions throughout the process. In addition, nearly quantitative yields of the hydroquinones (1,4-dihydroxybenzenes) are recovered for recycle along with the solvents, or for other commercial uses.

Preparation of nitrogen fertilizers from oxalate esters prepared by the

Process for the production of solid urea-nitric phosphate fertilizer

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.

Acid type solid urea-nitric fertilizer

A process for the preparation of nitrogen fertilizers, especially oxamide, either indirectly, or directly from oxalate esters, including the regeneration of the quinone oxidant utilized in the formation of the above esters. Preparation of oxalate esters as potential intermediates for nitrogen fertilizers by the oxidative carbonylation of alcohols with carbon monoxide in the presence of a catalytic amount of a platinum group metal salt with or without a corresponding metal oxidant salt and an optionally substituted quinone (substituted or unsubstituted 2,5-cyclohexadiene-1,4-dione). High yields of isolated dialkyl oxalates are obtained by regulating temperature and carbon monoxide pressure and by maintaining essentially anhydrous conditions. In addition, high yields of the hydroquinones (1,4-dihydroxybenzenes) are recovered.

Growing community of inventors

Florence, AL, United States of America

Jack M Sullivan