Abstract: A method of recovering uranium from wet-process phosphoric acid wherein the acid is treated with a mixture of an ammonium salt or ammonia, a reducing agent, and then a miscible solvent. Solids are separated from the phosphoric acid liquid phase. The solid consists of a mixture of metal phosphates and uranium. It is washed free of adhering phosphoric acid with fresh miscible solvent. The solid is dried and dissolved in acid whereupon uranium is recovered from the solution. Miscible solvent and water are distilled away from the phosphoric acid. The distillate is rectified and water discarded. All miscible solvent is recovered for recycle.

Abstract: Impure wet-process phosphoric acid is treated with urea by known processes to produce relatively pure urea phosphate which is then treated with oxalic acid to give solid urea oxalate and purified phosphoric acid product. The urea oxalate is either treated with ammonia to give urea and ammonium oxalate or it is pyrolyzed to produce urea and oxamide.

Abstract: An improved process for the purification of wet-process phosphoric acid (WPPA) with acetone and ammonia. The main product is the purified acid and a byproduct is the impure acid fraction in a liquid form containing most of the impurities including the added ammonia. The WPPA is mixed with acetone and the specified amount of ammonia to form two liquid phases that separate rapidly. The top layer contains about 75 percent of the phosphoric acid, nearly all the acetone, and a small fraction of the impurities. The bottom liquid layer has a viscosity usually in the range of 40 to 2500 centipoises, depending on the acid concentration and the amount of ammonia used. The acetone is distilled from the two liquid phases for recycle to the process.

Abstract: A process for the removal and recovery of sulfur oxides from gas streams by contacting the gas stream with an aqueous suspension of melamine whereupon a mixture of solid, hydrated melamine sulfites, hydrated melamine sulfate is formed. The solids are separated from the reaction product and the clarified liquid recycled. The solids are then heated to temperatures up to 200.degree. C. to decompose the hydrated melamine sulfites into free melamine, gaseous water, and sulfur dioxide, and the gaseous water and sulfur dioxide withdrawn as product. The hot solids are cooled and split into two portions. One portion is recycled and the other portion is treated with a base stronger than melamine to decompose the contained melamine sulfate into free melamine and a basic sulfate salt solution. The basic sulfate salt solution is separated from the melamine and withdrawn as product and the melamine is recycled to the process.

Abstract: A process for the production of fertilizers from phosphoric and sulfuric acids, anhydrous ammonia, and urea, and more specifically, the production of high-analysis granular ammonium phosphates, ammonium phosphate sulfates, and urea-ammonium phosphate sulfates--some with polyphosphate contents of up to 68 percent of the total P.sub.2 O.sub.5. A specially designed pipe-cross reactor is used to produce a homogeneous melt or slurry of low moisture content from the reactants and thus eliminates the need for a preneutralizer as used in many prior-art granular fertilizer processes. In addition, because of the low melt or slurry moisture content, the dryer (also used in most of the previous processes) is eliminated. The elimination of these two items greatly simplifies pollution abatement, since both items are sources of fumes and dust.

Abstract: A method of preparing dicalcium phosphate from phosphate rock wherein the rock is treated with a mixture of water, carbonyl, and sulfur dioxide. Solids are separated from the liquid phase. The solid phase consists of a mixture of gangue, and calcium .alpha.-hydroxysulfonate. Carbonyl and part of the sulfur dioxide are recovered from the solid by low temperature thermal decomposition. Dicalcium phosphate is precipitated from the liquid phase by partial distilling of SO.sub.2. All carbonyl is recovered for recycle.

Abstract: process for production of fertilizers from phosphoric and sulfuric acids, anhydrous ammonia, and urea, and for the production of high-analysis granular ammonium phosphates, ammonium phosphate sulfates, and urea-ammonium phosphate sulfates--some with polyphosphate contents of up to 68 percent of the total P.sub.2 O.sub.5. A specially designed pipe-cross reactor is used to produce a homogeneous melt or slurry of low moisture content from the reactants and thus eliminates the need for a preneutralizer as used in many prior-art granular fertilizer processes. Because of the low melt or slurry moisture content, the dryer is eliminated. The elimination of these two items greatly simplifies pollution abatement, since both items are sources of fumes and dust. The equipment used to produce granular monoammonium phosphate, diammonium phosphate, urea-ammonium phosphate sulfate, and ammonium phosphate sulfate fertilizers is inexpensive and simple to operate.

Abstract: liquid fertilizers having controlled release properties are prepared from fertilizer solutions and oil-surfactant mixtures. An invert surfactant is dissolved in an oil such as kerosene. The amount of surfactant used can vary over a wide range. Use of between 0.6 and 1.0 percent surfactant in the fertilizer formulation yields fertilizers with acceptable release rates. Liquid fertilizer is slowly added to the oil-surfactant mixture with vigorous agitation causing a water-in-oil emulsion to form. Mixtures containing 80 to 90 percent liquid fertilizer and 10 to 20 percent oil made excellent products.The final fertilizer product is an invert emulsion containing 80 to 90 percent liquid fertilizer, 10 to 20 percent oil, and 0.6 to 1.0 percent surfactant. The product consists of small droplets of liquid fertilizer solution surrounded by a thin but essential impenetrable oil-surfactant layer.

Abstract: a method of recovering uranium from wet-process phosphoric acid wherein the acid is treated with a mixture of an ammonium salt or ammonia, a metallic reducing agent such as iron, aluminum or zinc, and then a miscible solvent such as methanol. The precipitated solids, which are separated from the purified phosphoric acid, consist of a mixture of metal phosphates and uranium. This solid is dissolved in acid and the uranium recovered from the solution by liquid-liquid solvent extraction. The miscible solvent and some water are distilled away from the purified phosphoric acid. The distillate is rectified, the water discarded, and the miscible solvent recovered for recycle.When the miscible solvent is methanol, the optimum ranges of ammonia and methanol are 0.05 to 0.20 gram atom nitrogen per gram atom phosphorus and 1.93 to 3.15 pounds methanol per pound of orthophosphoric acid. The amount of reducing agent added should be sufficient to reduce all uraniun to U(IV).

Abstract: a process for the removal and recovery of sulfur oxides from gas streams by contacting the gas stream with an aqueous suspension of melamine containing an oxidation inhibitor such as para-phenylenediamine whereupon a mixture of solid, hydrated melamine sulfites and solid, hydrated melamine sulfate is formed. The solids are then separated from the reaction product and the clarified liquid recycled. The solids are then heated to temperatures up to 200.degree. C to decompose the hydrated melamine sulfites into free melamine, gaseous water, and sulfur dioxide, and the gaseous water and sulfur dioxide withdrawn as product. The hot solids are cooled and split into two portions. One portion is recycled and the other portion is treated with an aqueous inorganic base stronger than melamine such as ammonia or potassium hydroxide to decompose the contained melamine sulfate into free melamine and a basic sulfate salt solution.

Abstract: an improved method of purifying wet-process phosphoric acid by sedimentation, in which the crude acid is intimately mixed with an appropriate amount of finely divided silica or silicate. The result is that the absolute magnitude of the zeta potential of the suspended solids, particularly humus and gypsum, decreases to a value that allows them to aggregate, settle rapidly, and be removed by conventional methods. The Si:F ratio is increased, effecting a reduction of fluorine contamination. The rate of growth of gypsum crystals is increased, reducing the amount of post-precipitation of gypsum and other particulates. Because the rate of settlement is increased, the holding time prior to further processing, such as concentrating to merchant-grade acid, is decreased, reducing storage and space requirements and associated capital investment as well as investment in product inventory.

Abstract: a process for the production of high-purity urea-ammonium polyphosphate fertilizers from crystalline urea orthophosphate derived from the reaction of wet-process acid and urea. Initially, urea phosphate was pyrolyzed in one stage to give molten urea-ammonium polyphosphates that contained up to 95 percent of the phosphate as polyphosphate, dependent upon the reaction conditions used. Heat to effect condensation of orthophosphate with urea to form polyphosphate was provided by steam. Reaction conditions ranging from a retention time of 1 minute at 350.degree. F to 30 minutes at 260.degree. F were satisfactory. The pyrolyzate contained mixtures of urea, ammonium orthophosphate, and ammonium polyphosphates and was dissolved in aqua ammonia to yield clear liquid fertilizers containing 12 to 15 percent nitrogen and 18 to 29 percent P.sub.2 O.sub.5. Addition of either urea to the process to maintain a urea:biuret ratio of at least 16, or about 2 pounds NH.sub.3 per unit P.sub.2 O.sub.

Abstract: mixtures of the isomers of C.sub.18 and C.sub.16 branched-chain saturated fatty acids have been demonstrated to be satisfactory substitutes as flotation reagents in Florida phosphate rock flotation in place of commercial crude, refined, or blended tall oils, or other straight-chain aliphatic fatty acids derived from vegetive sources in which the unsaturated aliphatic fatty acid components are the principal or most effective flotation reagents, as opposed to the corresponding saturated straight-chain fatty acids. The title reagents consisting of saturated branched-chain fatty acids of similar carbon content (C.sub.16 - C.sub.18) can be used alone as acids, or as soap derivatives, or in blended mixtures with fuel oil, which reduces reagent comsumption and also increases the grade and recovery of phosphate concentrate.

Abstract: an improved process for the granulation or coating of hygroscopic or nonhygroscopic materials where melt is sprayed onto cascading granules of common or uncommon substrate in an enclosed vessel such as a rotary drum preferably with lifting flights which provide maximum mixing of the granules and the atmosphere enclosed in the unit and where heat given off by solidification of the melt is absorbed by evaporation of water which is atomized as an extremely fine mist into areas of the vessel which are not subtended by falling granules. Evaporation is effected without impingement of the mist on the granules or vessel internals. Air for evaporation is pulled through the vessel concurrent with the flow of granules and its moisture content is regulated below the critical humidity of the granules throughout the vessel.

Abstract: a method for improving the storage properties of liquid fertilizers made from wet-process phosphoric acid. The wet-process acid is essentially defluorinated so that when it is processed by ammoniation to make high-analysis ammonium polyphosphate liquid fertilizers, the sometimes almost immediate precipitation of undesirable sludge compounds of magnesium does not occur in the liquid over long periods of storage. The liquids may be produced by dissolving hot ammonium polyphosphate melts directly as it is produced or by dissolving dry granular solid ammonium polyphosphate made from this type acid.Both ammonium polyphosphate and urea-ammonium polyphosphate base solutions made from defluorinated wet-process acid are highly stable and they exhibit increased tolerance for higher magnesium and lower polyphosphate levels.

Abstract: an improved process for production of concentrated high-analysis nitrogen-phosphate base suspension fertilizer by ammoniation of wet-process or other orthophosphoric acids in two stages. The process improvement involves the addition of a small amount (0.1-0.5 percent) of a crystal modifier, fluosilicic acid, for prevention of settling of crystals in the suspension during vibration such as that which occurs during shipment. With use of the crystal modifier, the monoammonium phosphate crystals formed are small and needlelike, and suspension fertilizers with excellent shipping, storage, and handling properties are produced with an N:P.sub.2 O.sub.5 weight ratio in the range of highest solubility, about 0.27 to 0.33.

Abstract: method for granulating crystalline fertilizer borate yielding improved product re bulk blending, handling, and storage by processing solid feedstock with small amounts of mineral acid solution. The process, which requires no drying step, comprises an improved method for converting a relatively easily prepared, nongranular, fine-crystal boron compound, sodium tetraborate pentahydrate, to granular form suitable in particle-size distribution, hardness, solubility, and other important characteristics for direct inclusion into bulk blended fertilizers to produce homogeneous, nonsegregating blends according to methods preferred by blend manufacturers. It has the particular advantage over the melt-flaking-sizing method, presently employed commercial practice of conversion of sodium tetraborate pentahydrate to suitable particle-size distribution for blending, in that it is a low-energy process and does not elevate the boron content of the product.

Abstract: particulate carbonaceous matter in ammonium polyphosphate liquid made from impure wet-process phosphoric acid is removed batchwise by intimately mixing the liquid with a combination of selected organic flocculating agents and then allowing the mixture to separate. The particulate carbonaceous matter floats rapidly to the surface and the clarified liquid that contains essentially no particulate carbonaceous matter is withdrawn from the bottom of the separation vessel. The particulate carbonaceous matter, a minor portion of the input ammonium polyphosphate liquid, and the flocculating agents are then intimately remixed with an additional fresh charge of black ammonium polyphosphate liquid to allow reuse of flocculant not combined with the particulate carbon material in the original charge. This reuse of flocculant may be repeated as many as five times.

Abstract: A method of selectively extracting calcite and dolomite away from apatite in phosphate rock or phosphatic limestone wherein the phosphate rock or phosphatic limestone is treated with a mixture of sulfur dioxide, water, and a carbonyl compound. Solids are separated from the liquid phase. The solids consist principally of apatite admixed with clay, quartz, and other accessory minerals originally in the rock. The solids are heated to drive off adhering sulfur dioxide, water, and carbonyl. The liquid phase consists of carbonyl, water, sulfur dioxide, and magnesium and calcium ions. Heating this liquid preferentially precipitates CaSO.sub.3.1/2H.sub.2 O. This solid is filtered off and the filtrate further heated to precipitate MgSO.sub.3.3H.sub.2 O largely free of CaSO.sub.3.1/2H.sub.2 O. All offgas and filtrate is returned to the process. Examination of extraction results shows that high temperature extraction favors dolomite extraction and low temperature extraction favors apatite extraction.

Abstract: Embodiment No. 1. Urea phosphate prepared from wet-process phosphoric acid is heated with monopotassium orthophosphate in a mole ratio of 0.25 to 4.0 at 130.degree. to 200.degree. C. to form an ammonium potassium polyphosphate having an average chain length between 1.2 and 2.5. The ammonium potassium polyphosphate is dissolved in aqueous ammonia to yield concentrated fertilizer solutions containing the three major nutrients and over 50 percent total plant food.Embodiment No. 2. Phosphoric acid containing 54 to 76 percent P.sub.2 O.sub.5 is heated with urea (urea:H.sub.3 PO.sub.4 mole ratio 0.5 to 2.0) and monopotassium orthophosphate (urea:KH.sub.2 PO.sub.4 mole ratio 0.25 to 4.0) at 130.degree. to 200.degree. C. to form an ammonium potassium polyphosphate having an average chain length between 1.2 and 2.5. The ammonium potassium polyphosphate is dissolved in aqueous ammonia to yield concentrated fertilizer solutions containing the three major nutrients and over 50 percent total plant food.