Abstract: A method of purifying phosphoric acid solution produced in wet process using nanofiltration. The claimed method contains the following: (a) providing wet phosphoric feed (b) subjecting the said feed to a first nanofilter (c) produce sulfate solids (d) removing the solids (e) subjecting a second nanofilter.

Abstract: In alternative embodiments, the invention provides processes and methods for the recovery, removal or extracting of, and subsequent purification of uranium from a wet-process phosphoric acid using a continuous ion exchange processing approach, where the uranium is recovered from a phosphoric acid, or a phos-acid feedstock using either a dual or a single stage extraction methodology. In both cases an intermediate ammonium uranyl-tricarbonate solution is formed. In alternative embodiments, in the dual cycle approach, this solution is contacted in a second continuous ion exchange system with a strong anion exchange resin then subsequently recovered as an acidic uranyl solution that is further treated to produce an intermediate uranyl peroxide compound which is ultimately calcined to produce the final uranium oxide product.

Abstract: A method for minimizing the addition of water to a phosphoric acid production process is described. The method uses phosphoric acid to make down a flocculant that is added to the process in order to promote filtration or clarification of crude phosphoric acid. Preferably, the phosphoric acid is a crude, clarified phosphoric acid that is recycled from the phosphoric acid production process itself.

Abstract: The disclosure relates generally to the use of polymers to assist in aggregating mineral components in aqueous mineral slurries to release and separate individual components of the slurry, which may then be recovered from the slurry.

Abstract: Methods for preventing or reducing the formation of scale in a wet-process phosphoric acid production process by intermixing a scale inhibiting reagent at one or more step of the phosphoric acid production process in an amount sufficient to prevent or reduce scale are provided.

Abstract: A method and device for producing polyphosphoric acid burns a fuel in combustion air in a combustion chamber, sprays a spray fluid comprising substantially pure orthophosphoric acid and undertakes polymerization-condensation of the pure orthophosphoric acid. A polyphosphoric acid in the form of an acid mist accompanied by formation of gases which mix with combustion gases resulting from burning of the fuel is formed to reach a predetermined temperature, wherein the mixture causes sudden lowering of combustion gas temperature. The acid mix is separated from the gas mixture and the polyphosphoric acid is collected at a bottom of the combustion chamber and the gas mixture is outputted via a lower part of the combustion chamber separate from the collection of polyphosphoric acid.

Abstract: A process for the extraction of uranium compounds from wet-process phosphoric acid includes lowering the iron concentration of the wet-process phosphoric acid and reducing the valency of any remaining ferric iron in the wet-process phosphoric acid to ferrous iron, and then extracting uranium compounds from the wet-process phosphoric acid. The process can include separating a side stream from a feed stream of wet-process phosphoric acid, wherein the side stream has a greater concentration of the uranium compounds than the feed stream by filtration. Extracting uranium compounds from the wet-process phosphoric acid can be by ion exchange process or by solvent extraction.

Abstract: Process for purifying a stream comprising phosphoric acid and a first amount of impurities, comprising: forming a slurry of phosphoric acid crystals in a water mother liquor; separating the phosphoric acid crystals from the mother liquor by filtration in a wash column comprising a filtering element, while a packed bed of crystals coming from the slurry forms near such filtering element; washing the separated phosphoric acid crystals in the wash column by bringing a washing liquid in countercurrent to the crystals in the bed up to a wash front, where the washing liquid recrystallizes, the bed being subjected to a movement in the direction of such wash front; forming a purified stream comprising phosphoric acid and a reduced amount of impurities by melting at least part of the washed crystals; and extracting the purified stream from the wash column through a product outlet of the wash column; wherein water is introduced into the wash column, between the wash front and the product outlet and/or in a melting circ

Abstract: The invention relates to a process for the production of high purity phosphoric acid which has a very low content in antimony, and is suitable for food, pharmaceutical, or electronic industry.

Abstract: Methods for preventing or reducing the formation of scale in a wet-process phosphoric acid production process by intermixing a scale inhibiting reagent at one or more step of the phosphoric acid production process in an amount sufficient to prevent or reduce scale are provided.

Abstract: The present invention relates to a method for production of calcium compounds having very low content of phosphorus and boron from an impure calcium chloride, solution containing phosphorus and boron, which method comprises the following steps: a) addition of a FeCl3-solution to the calcium chloride solution, b) adjusting the pH of the solution by addition of a base to between 3 and 9.5 for precipitation of iron hydroxide, iron phosphate and boron compounds, c) removal of the solid precipitate from the solution in step b) obtaining a purified calcium chloride solution, d) precipitation of a calcium compound from the solution from step c), and e) separation of the calcium compound from the solution in step d).

Abstract: A chemical process to improve the filtration performance for the removal of gypsum from phosphoric acid/gypsum slurry using a filtration aid that is selected from a class of polymers, lower molecular weight anionic polyelectrolytes, which previously have not been used for this application. The polymer is CMC or Carboxymethyl Cellulose, which is a polymerized cellulose ether. CMC is found to be extremely effective for phosphoric acid/gypsum slurry that was produced from igneous phosphate rock. CMC is also available in food grade, which is novel for filtration aids for the production of phosphoric acid which may be used for human or animal feed.

Abstract: The invention relates to a method for the purification or recovery of orthophosphoric acid rich streams by suspension-based melt crystallization. The orthophosphoric acid is crystallized as the hemi-hydrate form and subsequent separation of such crystals in a wash-column produce a high purity acid/water solution that has been depleted of most of the metals and impurities other than water, thereby separating an orthophosphoric acid rich feed liquor into an ultra-pure orthophosphoric acid hemi-hydrate and a mother liquor containing almost all impurities originally present in the feed. The orthophosphoric acid rich feed liquor typically contains no more than 15 wt % water and 1 wt % other impurities. Individual metal ion composition in the purified orthophosphoric acid product is in the range of 100 to 1000 ppb (parts per billion= 1/1000 ppm) of each metal ion. The metal ion composition of the resulting purified product is thus typically below the detection limit of typical analysis equipment.

Abstract: The present disclosure is directed to a filter support having a surface with a plurality of perforations therein. At least one spray bar may be substantially fixed adjacent to the surface of the filter support. A spray bar may include a plurality of nozzles for directing a pressured fluid toward the filter support. The filter support may further include a motor for causing the filter support to move in a cyclical manner while the spray bar directs pressurized fluid toward the filter support.

Abstract: A method and system to consistently and automatically conditioning and delivering a solid-free liquid (filtrate) sample suitable for instrumental analysis is disclosed. A slurry, preferably a slurry produced by a sub-atmospheric pressure chlorate dioxide generating process, is fed through a filter to remove the solid phase and to provide the liquid phase on the downstream side of the filter, where the concentration of at least one dissolved component is determined.

Abstract: A process to improve the polymeric filtration aid performance used in removal of gypsum from phosphoric acid/gypsum slurry. A synergistic effect has been observed by using a Dual Injection method. This method more specifically involves using two polymers (A & B) of different chemistry and injecting into slurry at a different time. The polymer chemistry of filtration aid A is selected from the group consisting of non-ionic, and anionic polymers and the polymer chemistry of filtration aid B is selected from the group consisting of sulfonated polymers. The polymer (A & B) usage is reduced by around 50% and performance improved.

Abstract: A process for the treatment of phosphoric acid plant pond water facilitating the recovery of phosphorus values from the input pond water. In certain aspects the process recycles solids from a later stage neutralization and separation into the clarified liquid stream from an initial clarification and neutralization stage. A sufficient amount of solids are added to the clarified liquid stream to effect the pH-dependent precipitation of a phosphate product. In alternative aspects an intermediate pH-dependent precipitation of a phosphate product is achieved through the addition of a neutralizing agent. The phosphate product is further characterized by a low concentration of fluoride. In addition the phosphate product can be further processed to a high purity technical grade phosphoric acid. In certain aspects the process employs flocculating agents to enhance the formation of precipitates. In further aspects, methodologies taught herein facilitate the reduction of silica in the process streams.

Abstract: A recycling process is presented to treat spent waste acid solutions whereby useful products are produced. Spent waste acid containing inorganic and organic contaminants is mixed with a magnesium compound containing aluminum and iron compounds that form oxyhydroxide flocs that complex, react, sequester and/or co-precipate the contaminates from the admixture. The magnesium reacts with sulfate ions to form a high quality magnesium sulfate solution.

Abstract: High purity phosphoric acid having an Sb content of 200 ppb or less and a sulfide ion content of 200 ppb or less as impurity contents on a 85 weight percent H3PO4 basis. The high purity phosphoric acid is useful as an etching solution for semiconductor devices having a silicon nitride film, an etching solution for liquid crystal display panels having an alumina film, a metallic aluminum etching solution, an alumina etching solution for ceramics, a raw material of phosphate glass for optical fiber, a food additive, and so forth. A metallic material having low capability of forming a lithium compound penetrates through the whole thickness of the active material layer 5.

Abstract: A process to improve the polymeric filtration aid performance used in removal of gypsum from phosphoric acid/gypsum slurry. A synergistic effect has been observed by using a Dual Injection method. This method more specifically involves using two polymers (A & B) of different chemistry and injecting into slurry at a different time. The polymer chemistry of filtration aid A is selected from the group consisting of non-ionic, anionic, and cationic polymers and the polymer chemistry of filtration aid B is selected from the group consisting of sulfonated polymers. The polymer (A & B) usage is reduced by around 50% and performance improved.

Abstract: A process for purifying phosphoric acid includes removing volatile components from phosphoric acid rich in impurities to form a crude phosphoric acid liquid substantially free of volatile components; heating the crude phosphoric acid liquid to a temperature above 250° C. in order to decompose phosphoric acid in the crude phosphoric acid liquid and generate gaseous phosphoric anhydride; and introducing the gaseous phosphoric anhydride into water or a dilute phosphoric acid aqueous solution in order to hydrate the gaseous phosphoric anhydride to form phosphoric acid.

Abstract: A process for purifying phosphoric acid includes removing volatile components from phosphoric acid rich in impurities to form a crude phosphoric acid liquid substantially free of volatile components; heating the crude phosphoric acid liquid to a temperature above 250° C. in order to decompose phosphoric acid in the crude phosphoric acid liquid and generate gaseous phosphoric anhydride; and introducing the gaseous phosphoric anhydride into water or a dilute phosphoric acid aqueous solution in order to hydrate the gaseous phosphoric anhydride to form phosphoric acid.

Abstract: Use and reduction of wastewater or “pond water” created by the wet-process phosphoric acid manufacturing there is created a large amount of wastewater or “pond water” to substantially reduce or eliminate the discharge of pond water with contaminants to the environment. By partially treating pond water with known industry standard processes and using the treated pond water for use as required makeup or cooling water in an electric power generator or any other Industry requiring makeup, cooling or process water will substantially reduce or eliminate the need for the phosphoric acid manufacturers to discharge the contaminated water to the environment and reduce the quantity of fresh water that would normally be required by these other industries using the treated pond water for cooling or makeup water.

Abstract: A one-step method for production of green-colored, stabilized wet-process phosphoric acid in which black-colored, wet-process phosphoric acid containing incidental metallic impurities and a carbonaceous content of less than 1000 ppm is oxidized to produce a green-colored liquid having a carbonaceous content less than 500 ppm. A typical green-colored liquid product produced by this one-step process has an emf of greater than 800 mv.

Abstract: The present invention provides a purification method of phosphoric acid, which includes bringing phosphoric acid containing arsenic into contact with hydrogen halide, thereby to remove the arsenic from the phosphoric acid, and a purification method of phosphoric acid, which includes bringing phosphoric acid containing arsenic into contact with hydrogen halide in the presence of a compound capable of generating hydrogen halide under acidic conditions. According to the method for purifying phosphoric acid of the present invention, a completely new method for removing arsenic in phosphoric acid is provided, which does not require a filtration or deaeration step or shows a great amount of residual sodium, unlike a sulfide coagulation method. This method is applicable to high concentration phosphoric acid, particularly polyphosphoric acid, and can be practiced at a low cost.

Abstract: A simplified process for the partial purification of contaminated phosphoric acid plant pond water having a molar calcium plus magnesium to fluorine ratio greater than or equal to about 0.60, is described, in which the pond water is treated with a basic compound, clarified, aged, clarified again and re-acidified. The thus treated pond water, still containing the majority of the phosphate originally present, can then be concentrated via the removal of essentially pure water, using any conventional means of concentration, without the formation of solid precipitates.

Abstract: A process for the partial purification of contaminated phosphoric acid plant pond water is described, in which the pond water is treated sequentially, with two basic compounds, clarified, aged, clarified again and re-acidified. The thus treated pond water, still containing the majority of the phosphate originally present, can then be concentrated via the removal of essentially pure water, using any conventional means of concentration, without the formation of solid precipitates.

Abstract: A one-step method for production of green-colored, stabilized wet-process phosphoric acid in which black-colored, wet-process phosphoric acid containing incidental metallic impurities and a carbonaceous content of less than 1000 ppm is oxidized to produce a green-colored liquid having a carbonaceous content less than 500 ppm. A typical green-colored liquid product produced by this one-step process has an emf of greater than 800 mv.

Abstract: A method is provided for fixing and eliminating fluorine and phosphorus in waste water wherein the waste water includes a fluorophosphate compound in which hydrochloric acid is added to the waste water including the fluorophosphate compound. The waste water to which hydrochloric acid has been added is heated in order to decompose the fluorophosphate compound into hydrogen fluoride and phosphoric acid, while hydrogen chloride gas located within a treating vessel in which the waste water is contained is introduced into a condenser provided outside of the treating vessel, and then a calcium salt is added to the waste water after decomposition in order to fix and eliminate fluorine and phosphorus.

Abstract: The present invention provides a method, and an apparatus, for forming a prescribed concentration of a substance in a mixture with a fluid, from a comparatively dilute mixture. The mixture is most preferably a solution of a solute in a solvent. The following summary and description generally discuss the invention in terms of a particularly preferred solution and a preferred use for that solution; however, in its broadest embodiments, the invention encompasses both the use for other solutions, and the use for a suspension of a solid substance in a fluid to form a mixture (which can also be referred to as a slurry). The invention provides for significant economic, safety and qualify benefits over conventional evaporative systems.

Abstract: A method for the conditioning of phosphoric acid containing solutions is described, wherein the solution is converted to a solid material by adding an aluminium compound. This solid material can readily be stared in disposal sites because it is not water-soluble. This method is particularly suited for the conditioning of phosphoric acid containing solutions from metal processing. An apparatus (10) for carrying out the method comprises a mixing tube (12) with a longitudinal axis (M) as well as an inlet (14) and an outlet (16). A least two liquid supply nozzles (18 and 20) open into the mixing tube inlet (14) and, with respect to the inlet crosssectional area of same, into a central area. Moreover, at least one gas supply nozzle (22) which is arranged radially outward of the liquid supply nozzles (18 and 22) opens into the mixing tube inlet (14). The longitudinal axis (G) of each gas supply nozzle (22) is inclined relative to the longitudinal center axis (M) in such a manner that said axes do not intersect.