Abstract: A wet process phosphoric acid which has been treated with aluminosilicate after the first stage of clarification can be further stabilized against precipitation of solids during storage and transport and the solids from the crystallizer more economically used to make diammonium and triple superphosphate fertilizers by introducing a second stage of clarification of the acid at a P.sub.2 O.sub.5 concentration of 38 to 42 weight percent.

Abstract: Method for production of granular ammonium polyphosphate fertilizer in which ammonium polyphosphate melt is prepared in a simple inline reactor and distributed onto a bed of solids in a drum granulator to bind smaller fertilizer particles into granules. The desired polyphosphate content can be obtained in the granular product by adjusting the total heat input of the feed reactants to the reactor by means of energy conservation modifications to the system. Energy losses are controlled by use of a predetermined quantity of insulation so that varying amounts of the maximum theoretical heat input can be utilized to produce products of polyphosphate contents as desired.

Abstract: Black carbonaceous floc in wet-process phosphoric acid is removed by contact with an oxidizing agent during the neutralization step with ammonia. In an embodiment the black floc is removed in liquid fertilizers derived from wet-process phosphoric acid by reaction with an oxidizing agent at high temperatures.The oxidizing agent is preferably nitric acid.

Abstract: Stable, urea-sulfuric acid reaction products of predetermined composition containing mono- and/or diurea sulfates and less than 35 weight percent water are produced from concentrated, urea-sulfuric acid reaction product feeds of different compositions by simultaneously and separately adding a selected feed solution and reactant urea and/or sulfuric acid, and optionally water, to a reaction zone in stoichiometric proportions so that the composition of the total feed to the reaction zone corresponds to the predetermined composition. Reaction temperature is maintained at a level below the incipient decomposition temperature of the predetermined composition, and the resulting products are essentially or completely free of sulfamic acid and/or ammonium sulfamate.

Abstract: Phosphate rock, including low grade phosphate ore, is treated to recover phosphoric acid and other valuable products by a series of steps including contacting phosphate ore with a weak phosphoric acid to form a suspension of at least a portion of the slimes contained in the ore so that the slimes can be separated from the ore, and separating the slimes to provide a deslimed phosphate ore. Deslimed phosphate rock is solubilized with phosphoric acid to convert at least a portion of the calcium contained in the rock and form a solution of monocalcium phosphate and phosphoric acid. After removal of solids, this solution can be treated with sulfuric acid in a gypsum crystallizer to form gypsum and the phosphoric acid product wherein filterable gypsum crystals are obtained by maintaining a total SO.sub.3 content of 1.5-4 wt. % in a first crystallizer and neutralizing the SO.sub.3 in a second crystallizer.

Abstract: A process and product of waste recovery at phosphorus furnaces is disclosed wherein small sized discrete particles of carbonaceous material or beneficiated phosphate ore are mixed with a mineral axis, an alkaline fluid and water, and the reacted mixture is tumbled in a horizontal cylinder at a temperature below that at which the carbonaceous material oxidizes to form agglomerates which are then indurated to discrete particulate size as desired for a charge component; the agglomerates are fed to a phosphorus smelting furnace together with other materials needed to make elemental phosphorus, furnace gases are cooled with recirculating water, a side stream of the water is taken off, treated, and used as feedstock in fluid fertilizers. The side stream of water contains elemental phosphorus, and the side stream is used as make-up water in fertilizer processes. Apparatus is disclosed for agglomerating coke and phosphate and, further, for measuring the abrasion and shatter resistance of agglomerates.

Abstract: A process for inhibiting the growth of insoluble magnesium-containing solids in liquid fertilizer compositions, prepared from the ammoniation of wet process phosphoric acids, comprises the addition of surfactant compounds to the fertilizer.

Abstract: A process for the production of fluid fertilizers (suspensions and/or solution type) made from merchant-grade phosphoric acid (50-58 percent P.sub.2 O.sub.5), sulfuric acid, liquid anhydrous ammonia, and water, wherein liquid ammonia is heated in heat exchange means juxtaposed hot fertilizer product to form gaseous ammonia, which gaseous ammonia, along with phosphoric acid and sulfuric acid, is fed to a pipe-cross reactor wherein a melt of ammonium polyphosphate sulfate is formed, which melt is subsequently mixed with cooled recycled product to produce a fluid fertilizer with N:P.sub.2 O.sub.5 weight ratios ranging from about 0.3 to 1, which contains from about 10 to 60 percent of its P.sub.2 O.sub.5 values in the form of polyphosphates and 3 to 8 percent by weight sulfur. About 45 percent of the P.sub.2 O.sub.5 as polyphosphate is easily attainable in the product with ambient acid feed temperatures, i.e., about 50.degree. F. to 100.degree. F.

Abstract: An improved process for the production of concentrated, high-grade, nitrogen-phosphate (N--P.sub.2 O.sub.5) base suspension fertilizer from wet-process or other phosphoric acids and ammonia. The process involves addition of small proportions of fluosilicic acid during preparation of the suspension to cause modification of monoammonium phosphate crystals to shapes and sizes that do not settle during vibration such as occurs during shipment.

Abstract: A body of liquid, such as an aqueous fertilizer mixture, in a tank is stirred and mixed by apparatus which produces a pattern of recirculating flow including a zone of rapid streamline flow in the tank, preferably an upwardly diverging conical pattern and preferably at an eccentric point in the tank. An addition component in fluid state, such as anhydrous liquid ammonia, is injected into the rapidly flowing liquid in a plurality of fine streams from a stationary injection manifold so as to produce an intimate dispersion of finely divided addition fluid at spaced points in the mixture which is immediately carried away from the injection area and widely dispersed in the liquid mixture. When anhydrous ammonia is thus dispersed in a fertilizer mixture containing a suitable reactant, such as phosphoric acid (H.sub.3 PO.sub.

Abstract: Aqueous ammonium phosphate solutions can be produced using an apparatus comprising: a fluid reactor having a plurality of inlets at one end thereof suitable for the admission of phosphoric acid, ammonia and water, the inlets being so positioned as to provide for rapid ammoniation of the phosphoric acid with the evolution of heat, to produce a reaction product mixture containing a liquid portion and steam, the fluid reactor having an exit for the expulsion of the reaction products mixture at the other end thereof, by steam generated by the heat liberated in the ammoniation process; a columnar vessel having an outlet at one end and, at the other end, enclosing the exit of the fluid reactor, a plurality of barriers obturating the columnar vessel in a spaced-apart relationship, and having a plurality of apertures therein for the passage of reaction products mixture therethrough; an inlet quench device connected to the columnar vessel for introduction therein of a liquid aqueous quenching fluid; and, a device in c

Abstract: An energy efficient process and apparatus is described that allows production of concentrated polyphosphate containing ammonium phosphate suspension fertilizers that can be stored and handled at temperatures well below 0.degree. F. Ammoniation of the merchant-grade wet-process phosphoric acid provides all of the heat required by the process. Use of a unique enlarged dual pipe-type reactor system allows operation for extended periods without clogging. To obtain the high concentration and excellent low temperature storage and handling properties, the ammonium phosphate must be produced within closely specified and previously undisclosed N:P.sub.2 O.sub.5 and solution concentration ranges. Operation outside the specified composition range will reduce the maximum plant food concentration and may cause some of the ammonium phosphate salts to crystallize and foul the heat-transfer surfaces.

Abstract: Phosphoric acid and ammonia are reacted together with additions of water when necessary in a reaction vessel to form a molten entrained stream reaction mixture to which a water quench is added to produce an ammonium polyphosphate liquid fertilizer.

Abstract: NP- or NPK-containing fertilizers are manufactured from low-grade phosphate ore digested by nitric acid. Substantial problems have been experienced during previous attempts to produce fertilizers from phosphate ore having a high content of magnesium. The problems relate to the solution's viscosity, which becomes extremely high during neutralization with ammonia of the mother liquor, obtained by removal of most of the calcium as calcium nitrate-tetrahydrate from the digested phosphate. The novel process solves the viscosity problems by adjusting the conditions during ammoniation and the subsequent evaporation before prilling or granulation. The adjustment is characterized in that a substantial part of the remaining calcium is kept outside the process itself, at least during the neutralization and evaporation stages.

Abstract: A process is disclosed for the absorption of gaseous or liquid ammonia in acid solutions or slurries, including an ammonia absorption zone separated from a water vapor generation zone disposed at a higher level. A pressure difference is created between the two zones, so that the ammonia absorption takes place completely in the neighborhood of the point of inflow of the ammonia, with a temperature increase localized only near to said inflow point, and thus without giving rise to the generation of water vapor which therefore takes place in a liquid-vapor separation zone located at a higher level with respect to the ammonia absorption zone. The acid solutions or slurries to be neutralized may consist essentially of solutions of phosphoric acid, sulphuric acid, nitric acid, solutions resulting from the nitric acid attack on phosphorites, acid slurries resulting from nitric acid attack or sulphonitric acid attack on phosphorites, or mixtures thereof.

Abstract: A one vessel process for manufacturing stable ammonium phosphate fertilizer utilizes a spray reactor in which phosphoric acid is reacted with ammonia to form ammonium phosphate. The ammoniation is conducted under conditions which form sufficient ammonium polyphosphate to stabilize the solution in the liquid condition. The liquid may be stored and transported without substantial solidification or crystalization so that the product may be subsequently used as an ammonium phosphate fertilizer.

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 and the clarified liquid 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 intimately remixed with fresh black ammonium polyphosphate liquid to allow reuse of flocculant not combined with the original particulate carbonaceous material. The flocculants may be reused as many as five times. The particulate carbonaceous matter, the inactive flocculant, and a minor portion of the input ammonium polyphosphate liquid are then processed into fluid or solid fertilizers. In some instances, more flocculant is added to the mixing vessel.

Abstract: Process for the production of solid ammonium polyphosphate in which ammonium phosphate melt is prepared in a pipe reactor and is solidified by controlled cooling to form crystals of a size and in quantity suitable to yield a hard, nontacky, and friable solid. Wet-process phosphoric acid is ammoniated in a pipe reactor to an NH.sub.3 :H.sub.3 PO.sub.4 mole ratio of about 1.0, and the resulting melt is agitated and simultaneously partially cooled by application of recycled pulverized product or air or a water jacket. The partially cooled melt is then solidified continuously into nontacky sheets on a water-cooled metal surface using warm water to slowly remove sensible heat and heat of crystallization. Up to about 55 percent or higher of the P.sub.2 O.sub.5 in the product may be polyphosphate. Without controlled cooling, a supersaturated solution or a microcrystalline texture results and the product is rather like a gel.

Abstract: A method of purifying filter-grade wet-process phosphoric acid, then converting the purified phosphoric acid directly to ammonium phosphate without first concentrating the phosphoric acid. The wet-process phosphoric acid is treated with a mixture of ammonia or an ammonium salt and acetone near or at the boiling point of the mixture. Solids are separated from the phosphoric acid liquid phase. The solids are a mixture of metal phosphates, gypsum, and fluosilicates. Adhering phosphoric acid is washed free of the solids with fresh acetone. Wash liquor is combined with purified phosphoric acid. Gaseous ammonia is added to the phosphoric acid-acetone extract in the ratio necessary to produce either monoammonium phosphate (MAP) or diammonium phosphate (DAP). Ammonium phosphate is filtered from the acetone-water mother liquor, then, depending on the level of ammonium phosphate left in the mother liquor and the type of ammonium phosphate produced (MAP or DAP), the mother liquor is treated in one of several ways.

Abstract: A process is described for the production of ammonium polyphosphate employing a novel reactor configuration and reaction technique to convert wet-process phosphoric acid having a low polyphosphate content and anhydrous ammonia into an ammonium polyphosphate product having a high proportion of the total P.sub.2 O.sub.5 in the polyphosphate form while minimizing operational problems such as scale build up on the reactor walls and subsequent conversion of the polyphosphate formed to orthophosphate.

Abstract: Liquid ammonia, a reactant with superphosphoric acid in the process for fertilizer production, is passed through an annular jacket surrounding a tubular reaction zone where reaction occurs to maintain the interior surface of the tubular reactor at a temperature sufficiently low to prevent the formation of scale on interior reactor surfaces.

Abstract: The invention provides a novel process for the removal of fluorine during the production of fertilizer by precipitating the ion during the ammoniation step and recovering same by pyrolysis.To recover the fluorine the fertilizer is first separated out as a filtrate and the precipitate is heated to evolve ammonium fluoride, which heating is done in an ammonia atmosphere.

Abstract: Animal feed grade phosphates such as mono-calcium phosphate, di-calcium phosphate or mixtures thereof are produced by direct reaction between phosphoric acid and Ca-containing materials. A finely ground, preheated calcium carbonate suspension is brought to react with a suitable quantity of preheated phosphoric acid by introducing the reactants into a short, tubular reaction zone, open at one end, whereby development of gas and intensive mixing of the reactants in the reaction zone take place. The gas formed by the reaction expels or ejects the foaming reaction mixture from the tube-like reaction zone, the reaction being substantially completed while the individual particles of the mixture are freely suspended in air or gas, whereafter the reacted mixture is collected in the form of a free-flowing granulate having improved handling properties, without any further quenching treatment of the granules.

Abstract: The present invention relates to a process for reacting ammonia and wet process phosphoric acid to produce ammonium phosphates, which process comprises feeding the reagents to a vessel comprising two tubular members in fluid flow communication with one another and with a gas disengagement vessel, at least one of said tubular members being generally upright, the ammonia being fed to the basal portion of the upright member, the phosphoric acid being fed to the other tubular member; allowing the resultant reaction mixture to circulate spontaneously up the upright member, through the gas disengagement vessel and through the other member to the upright member; and recovering the ammonium phosphate reaction products from the reaction system.

Abstract: A process for granulating ammonium phosphate containing composition for use as a fertilizer which comprises feeding a slurry or melt of ammonium phosphate, wherein said slurry or melt is capable of further reaction with ammonia, into a kneading mill, feeding recycled particles from the subsequent classification and crushing procedure into said kneading mill, wherein the said slurry or melt added to the mill is from 5 to 95% wt.

Abstract: A simplified, commercially feasible, split-addition method of producing a liquid, sprayable fertilizer composition which contains ammonium phosphates is disclosed which yields a fertilizer with improved storage properties over prior compositions of this type and capable of being sprayed using existing equipment with a minimum of clogging problems. The method includes initially admixing a fractional portion of a total quantity of monoammonium phosphate (MAP) to be employed with water and adding ammonia thereto so as to induce an essentially instantaneous ammoniation reaction; the remainder of the MAP is then added to yield the final fertilizer composition. The addition of a suspending agent is usually desirable. This split addition of MAP (most preferably a 70% - 30% split) unexpectedly serves to minimize formation of large ammonium phosphate crystals in the fertilizer, so that the storage properties are improved and the composition can be sprayed without fear of frequent clogging of the spraying equipment.

Abstract: When crude wet process phosphoric acid is solvent extracted, an aqueous raffinate containing phosphoric acid and a small amount of solvent is produced as a by-product. Certain materials are added to the raffinate, in order to produce two phases, one aqueous and the other of solvent. The phases are separated, the solvent recycled for reuse in a solvent extraction process and the aqueous phase treated with ammonia or alkali or alkaline earth metal compounds to form a fertilizer or other phosphate salt.

Abstract: Phosphate values can be recovered from an organic extract which is formed by contact of wet process phosphoric acid and a water immiscible solvent, in a process in which the extract is treated with an inorganic base or a dihydrogen phosphate salt to give an acid free solvent and an aqueous solution of phosphoric acid and phosphate salt with a cation to P usually in the 0.1 - 0.5 : 1 region. The aqueous solution represents a concentrated soluble phosphate source for subsequent neutralization and conversion to e.g. tripolyphosphates.

Abstract: Ammonium polyphosphate is manufactured on a continuous basis by reacting gaseous ammonia and aqueous phosphoric acid at elevated temperatures in a one or multiple stage falling film reaction zone in the presence of a diluting gas if desired, using wet phosphoric acid, preferably containing 28-32%, by weight P.sub.2 O.sub.5 and an excess of ammonia. The phosphoric acid and the gaseous ammonia are preferably carried in counterflow and the temperature in the falling film reaction zone is adjusted using heat transfer fluids to within the range of 120.degree. - 260.degree. C.

Abstract: A stable, homogeneous, and flowable soil neutralizing slurry of particulate material such as calcium carbonate or dolomitic lime as provided using a suspending agent and a dispersant. A polyanionic dispersant is used in limited quantities to increase the concentration of particulate material and a gelling grade clay mineral is used as a suspending agent to prevent settling of the dispersed particulate material. A partial dispersion technique is used whereby the amount of dispersant used is limited so that the particulate material is dispersed but not the clay mineral.

Abstract: Crude phosphate is leached with nitric acid to produce an acid slurry, which is thereafter neutralized with ammonia in two successive stages while simultaneously cooling it and adding acid, part of the crude phosphate phosphorus being replaced with phosphoric acid added to the slurry to be neutralized, and in such a manner that at maximum 40% of the phosphoric acid is fed to the first neutralization stage and the rest is fed to the second neutralization stage, whereby the acidity of the slurry is adjusted to pH 2.5 - 4.5 during the first and to pH 5.0 - 6.0 during the second neutralization stage.

Abstract: A process for preparing concentrated, high-grade, nitrogen-phosphate (N--P.sub.2 O.sub.5) base suspension fertilizer from wet-process or other impure orthophosphoric acids. The process involves a new procedure for the direct ammoniation of orthophosphoric acid in stages for production of fluid, high-analysis, N--P.sub.2 O.sub.5 suspension fertilizer with good physical properties. The new process contains a novel method for prevention of settling of crystals in the suspension during vibration, such as that which occurs during shipment. Settling is avoided by producing small, thin crystals of diammonium phosphate through control of the N:P.sub.2 O.sub.5 ratio and temperature in the second and third ammoniation stages.

Abstract: Precipitate settling in ammonium polyphosphate liquid fertilizer solutions containing magnesium, iron, aluminum compound impurities, prepared by concentrating and ammoniating wet process orthophosphoric acid, is impeded by addition to the ammonium polyphosphate, prior to precipitate formation, a source of Cl.sup.- in amounts sufficient to alter the morphology of the precipitate crystals such that the length-to-width ratio of the crystals formed is increased by at least 200%, as compared to the ratio for crystals formed in the absence of Cl.sup.- addition. Since there is little propensity for the longer and thinner crystals to settle out of solution, the crystals remain innocuously suspended in the solution.

Abstract: Stable aqueous ammonium phosphate containing a higher proportion of polyphosphates is obtained by reacting phosphoric acid with ammonia in the presence of sulfuric, nitric or hydrochloric acids under conditions sufficient to produce a partially neutralized melt containing polymeric phosphates at a temperature between 400.degree. and about 750.degree. F. by the autogenous heat of neutralization, quenching and further neutralizing the melt.

Abstract: A process for the production of a granular fertilizer material from sludge materials discharged from scrubbing processes that remove pollutants from boiler flue gases. Waste sludge discharged from flue gas scrubber systems often contain large amounts of calcium and sulfur as well as lesser amounts of other compounds known to have plant nutrient value. The sludge is treated with an acid such as phosphoric, sulfuric or nitric, or a mixture of these, and ammonia. The resulting sludge-ammonia-acid salt mixture is combined with partially dried, previously processed solid material (recycle) in a horizontal rotating vessel. Additional ammonia and/or acid is added to the rotating vessel to cause the sludge-salt mixture to solidify and granulate. Other plant nutrients may be added to the rotating vessel during granulation. The granulated material discharged from the rotary vessel is further processed (dried, cooled, and screened) to obtain desirable moisture content and particle size.

Abstract: Ammonium polyphosphates are prepared by a process which comprises heating melamine orthophosphate prepared from impure wet-process phosphoric acid in a stream of gaseous ammonia at a temperature between 150.degree. C and 210.degree. C to produce a mixture of melamine and relatively pure short-chain ammonium polyphosphates. The solid product is extracted with water to remove the ammonium polyphosphates and free the insoluble, crystalline melamine for recycle. Thus, the only starting materials consumed in the process are phosphoric acid and ammonia.

Abstract: The invention relates to a process for the manufacture of solid monammonium phosphate with good granulation properties suitable for use in compound fertiliser manufacture. An improvement in product quality is obtained when between 20% and 80% of an aqueous slurry of ammonium phosphate, formed by the ammoniation of wet-process phosphoric acid, is mixed with a second acid prior to entry into a moisture disengagement unit. This treatment precipitates some monammonium phosphate crystals which provide nuclei for further crystal growth. After a short time delay to allow crystals to form, the remainder of the slurry is then added separately to the moisture disengagement unit.

Abstract: Ammonium phosphates are produced from wet-process phosphoric acids containing silicon and fluorine compounds by preconcentrating the acid and evolving some of the water, silicon and fluorine compounds as a vapor phase, maintaining it at a temperature above about 50.degree. C., neutralizing the liquid acid concentrate with ammonia, and absorbing the isolated vapor phase from the evaporation zone in a relatively cool, neutralized ammonium phosphate solution at a pH of at least about 5.5.

Abstract: Phosphoric acids having H.sub.2 0/P.sub.2 O.sub.5 mole ratios of about 4.5 or less are converted to aqueous solutions of ammonium polyphosphates of which at least about 40 percent of the P.sub.2 O.sub.5 is present as acyclic polyphosphates. The reaction is conducted at 500.degree. to about 750.degree. F. sufficient to increase the polymeric P.sub.2 O.sub.5 content at least 10 percent by reacting a highly dispersed, unconfined acid spray with substantially anhydrous ammonia. High conversions to polymeric species are obtained while minimizing both reactor fouling when using impure wet-process acids, and corrosion occurring with either wet-process or "white" acids.

Abstract: A novel process for making monoammonium phosphate includes a pre-neutralizing step, a pipeline reactor step, and the projection of a stream of reactants from the pipeline reactor onto a moving belt, to result in a foamed, dry friable product.

Abstract: The invention relates to a process for the manufacture of solid monammonium phosphate in a suitable form for use as an ingredient in the granulation of NPK compound fertilizers. It has been found that some wet-process phosphoric acids used in the manufacture of fertilizer grade ammonium phosphate contain impurities in amounts and/or ratios which can give rise to hard oversize product in known methods of manufacture with the result that extra milling of the product is required. The process of the invention overcomes the need for extra milling by providing an improved product form. The improvement is achieved by mixing separately at one stage in a process of the kind described between 15% and 85% by volume of the total secondary acid feed with the aqueous ammonium phosphate slurry and adding the remainder of the secondary acid to the treated slurry at a later stage.

Abstract: In the process according to the invention, raw phosphate rock is decomposed with an aqueous solution of sulfuric acid and ammonium sulfate recycled from the conversion step of phosphogypsum into chalk, and then the decomposition liquor stream is divided into a partial acid plant stream (Liquor I) to be converted into phosphoric acid and a partial fertilizer plant stream (Liquor II) to be processed to a multi-component mineral fertilizer. From the acid plant stream (Liquor I) constituting up to 30 per cent by weight of the total decomposition stream, ammonium sulfate is precipitated and introduced into the fertilizer plant stream (Liquor II), all the above mentioned processes of decomposition, separation and precipitation being carried out continuously.

Abstract: Stable sludge-free ammonium polyphosphate fertilizer solution is prepared by introducing ammonia and a blend of impure wet process phosphoric acid having a P.sub.2 O.sub.5 content of 58 to 68% and solvent extracted wet process phosphoric acid of reduced Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, MgO and free H.sub.2 O content into a reactor wherein the mixed reactants are retained for at least about 0.10 second after which the reaction product is immediately quenched and the resulting solution aged to effect precipitation and nucleation of suspended insoluble metallic phosphates and insoluble organic matter, and filtered.

Abstract: A process for the production of a granular fertilizer material from sludge materials discharged from scrubbing processes that remove pollutants from boiler flue gases. Waste sludge discharged from flue gas scrubber systems often contain large amounts of calcium and sulfur as well as lesser amounts of other compounds known to have plant nutrient value. The sludge is treated with an acid such as phosphoric, sulfuric or nitric, or a mixture of these, and ammonia. The resulting sludge-ammonia-acid salt mixture is combined with partially dried, previously processed solid material (recycle) in a horizontal rotating vessel. Additional ammonia and/or acid is added to the rotating vessel to cause the sludge-salt mixture to solidify and granulate. Other plant nutrients may be added to the rotating vessel during granulation. The granulated material discharged from the rotary vessel is further processed (dried, cooled, and screened) to obtain desirable moisture content and particle size.

Abstract: Ammonium phosphate solutions free of precipitates are prepared from wet-process phosphoric acid containing incidental metallic impurities such as iron, aluminum and magnesium by concentration of the phosphoric acid to an anhydrous state and the formation of acyclic polyphosphoric acids therein which prevent the precipitation of the metallic impurities upon neutralization. The acid is heated to a temperature greater than 120.degree. C. at atmospheric or subatmospheric pressures while removing the volatile impurities and thereafter is neutralized with ammonia. The neutralization step can be performed at elevated temperatures with anhydrous ammonia or the acid can be cooled and neutralized at ambient temperatures. The resulting ammonium phosphate is diluted with water to obtain an ammonium phosphate solution which is clear and free of precipitates.

Abstract: A process for preparing concentrated, high-grade, nitrogen-phosphate (N--P.sub.2 O.sub.5) base suspension fertilizer from wet-process or other impure orthophosphoric acids. The process involves a new procedure for the direct ammoniation of orthophosphoric acid in stages for production of fluid, high-analysis, N--P.sub.2 O.sub.5 suspension fertilizer with good physical properties. The new process contains a novel method for prevention of settling of crystals in the suspension during vibration, such as that which occurs during shipment. Settling is avoided by producing small, thin crystals of diammonium phosphate through control of the N:P.sub.2 O.sub.5 ratio and temperature in the second and third ammoniation stages.

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: 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: 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: An energy efficient process and apparatus is described that consists of a pipe reactor, melt dissolution tank, acid and ammonia heat exchangers, product cooler, and clay addition facilities in which a concentrated polyphosphate containing ammonium phosphate suspension fertilizers is produced that can be stored and handled at temperatures well below 0.degree. F. The suspension is produced from merchant-grade wet-process phosphoric acid which is ammoniated in a unique enlarged pipe-type reactor sized to have throughputs of 20-100 pounds P.sub.2 O.sub.5 /hr-in.sup.2 and 0.25-2 pounds P.sub.2 O.sub.5 /hr-in.sup.3 of internal reactor area and volume, respectively, and which can be operated for extended periods without clogging. All of the heat required by the process is obtained by transferring a portion of the heat of ammoniation from the hot liquid in the melt dissolution tank to the incoming acid and ammonia streams. The resultant product contains 10 to 40 percent polyphosphate and when produced within an N:P.