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4028237 |
Method and apparatus for treatment of fluorine-containing waste waters
There are disclosed methods for removing fluorine values from fluorine-containing waste waters, in which aluminum ions are added to fluorine-containing waste water to convert fluorine to...
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4026995 |
Process for defluorination of commercial phosphoric acid
A process is provided for the defluorination of wet process phosphoric acid whereby hydrogen ion is removed, and the concentration of P 2 O 5 is adjusted with water, the calcium concentration,...
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4026990 |
Production of low-fluorine gypsum as a by-product in a phosphoric acid process
A process for purifying waste gypsum from the wet phosphoric acid process to a maximum fluorine content of 0.25 % by weight based on the anhydride, which comprises adding active silicic acid in two...
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4016238 |
Process for the obtention of alumina and phosphate values by the alkaline decomposition of silica-containing aluminum phosphate ores
A process for the obtention of alumina and phosphate values by the alkaline decomposition of silica-containing aluminum phosphate ores comprises reducing the ore to a particle size of from about 6...
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4011301 |
Ammonium phosphate production and the reduction of fluorine and silicon emissions
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...
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4000067 |
Method for rapid sedimentation of fine particles from suspensions
Suspensions of fine particles such as phosphate ore slimes are caused to settle by reaction with hydrofluoric acid or equivalent F-containing material in order to effect rapid settling of particles...
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3993735 |
Cleanup of wet process phosphoric acid
A method for purifying a crude or wet process phosphoric acid to a technical grade phosphoric acid comprising a sequence of steps including diluting the crude phosphoric acid, contacting the crude...
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3991164 |
Process for the dearsenication of polyphosphoric acid
Polyphosphoric acid is dearsenicated by placing the polyphosphoric acid in a reactor; adding a phosphorus oxo-compound containing phosphorus in the monovalent or trivalent electropositive oxidation...
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3982036 |
Calcium phosphate and calciumchlorophosphate compositions
Novel feed grade calcium phosphate compositions are provided which contain calcium chlorophosphate in varying amounts. This novel composition and other heretofore known varieties of feed grade...
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3967948 |
Purification of phosphoric acid with urea and nitric acid
My invention relates to a new method for purification of wet-process phosphoric acid with co-production of nitrogen solution. The crude acid is treated with urea by known processes to form urea...
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3966877 |
Method of processing of waste gases
A method of processing of waste gases containing hydrogen fluoride and silicon tetrafluoride or hydrogen fluoride, silicon tetrafluoride and sulfur dioxide by absorption of hydrogen fluoride and...
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3949047 |
Method of precipitating radium to yield high purity calcium sulfate from phosphate ores
In the manufacture of phosphoric acid by treatment of phosphate ores with excess phosphoric acid and precipitation of calcium ions as calcium sulfate, the purity and quality of the byproduct...
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3943232 |
Process for the defluorination of dilute fluorine containing aqueous acid solutions
A process is provided whereby dilute aqueous phosphatic acid solutions of 2 to 3 percent or less and containing generally less than 1 percent fluorine are substantially quantitatively defluorinated...
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3907680 |
Clarification of aqueous acidic phosphatic solutions
Crude aqueous acidic phosphatic solution such as wet process weak phosphoric acid, 25% P 2 O 5 to 35% P 2 O 5 , is passed through a layer of especially prepared perlite filter aid thereby...
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3907973 |
Process for defluorinating phosphoric acids and production of ammonium fluosilicate and fluosilicic acid
A process for removing fluorine from phosphoric acid solutions comprising combining relatively dilute (e.g., 28% P 2 O 5 ) fluorine-containing phosphoric acid with up to about 2% colloidal silica,...
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3903247 |
Cleaning of phosphoric acid
Cleaning of phosphoric acid. An aqueous phosphoric acid starting solution is extracted with a mixture of 75-95% by weight of at least one dialkyl ether in which each alkyl radical has 2-5 carbon...
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3894143 |
Process for the manufacture of crystallized ammonia phosphates
A method of obtaining crystallized ammonium phosphate of good quality using ammonia and technical grade phosphoric acid that was liberated from the major portion of impurities after precipitation...
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3890097 |
Method of purifying wet process phosphoric acid
The present invention relates to a method of purifying wet process phosphoric acid wherein the phosphoric acid solution is diluted with sulfuric acid, the diluted acid solution is cooled to a...
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3872215 |
Phosphate purification process
Crude phosphoric acid is mixed with an organic solvent or solvent mixture having the ability to absorb at least 9 weight-% water as based on solution weight. From this mixture, a water/phosphoric...
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3870786 |
Removal of phosphate compounds from fluoride containing solutions
A process for removing phosphate compounds such as phosphoric anhydride (P 2 O 5 ) from fluoride containing solutions such as dilute hydrofluoric acid (HF) or fluosilicic acid (H 2 SiF 6 ) is...
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3867511 |
SOLVENT EXTRACTION OF H3 PO4
Purified phosphoric acid is obtained from phosphate rock by digesting the rock with sulfuric acid, separating the resulting dilute phosphoric acid liquor and solubilized impurities from the calcium...
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3862298 |
PROCESS FOR THE TREATMENT OF A SALT-CONTAINING ACID SOLUTION
A process for treating a salt-containing acid solution is described wherein the cations contained therein are effectively removed by contacting such solution with an organic solvent to precipitate...
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3853486 |
PROCESS FOR THE MANUFACTURE OF PYROPHOSPHORIC ACID BY CRYSTALLIZATION
Production of pure, crystallized pyrophosphoric acid with a strength of at least 95 percent. A polyphosphoric acid is treated so as to establish a P 2 O 5 -concentration between 79 and 81 weight...
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3800029 |
PROCESS FOR RECOVERING SODIUM FLUOSILICATE FROM WET PROCESS PHOSPHORIC ACID
Sodium fluosilicate of high quality is recovered from wet process phosphoric acid by adding a sodium compound to phosphoric acid not containing substantial amount of fluosilicic acid dissolved...
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3764655 |
PROCESS FOR PURIFYING PHOSPHORIC ACIDS BY NEUTRALIZATION WITH AN ALKALI METAL HYDROXIDE AND/OR CARBONATE
Phosphoric acids produced by subjecting phosphate ores to wet-processing with mineral acids are purified by neutralizing them in a four step process by means of an alkali metal hydroxide and/or...
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3764657 |
PROCESS FOR REMOVAL OF CATIONIC IMPURITIES FROM TECHNICAL GRADE PHOSPHORIC ACID
Technical grade phosphoric acid is purified of cationic impurities by adding thereto alkali or ammonium ions and a water soluble organic solvent whereby a flaky, easily filterable precipitate is...
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3764658 |
PRODUCTION OF FLUOSILICIC ACID
An improved process for the recovery of fluosilicic acid from recycle streams in the manufacture of phosphoric acid by the sulfuric acid digestion of phosphate ore.
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3734696 |
VANADIUM RECOVERY FROM ACIDIC SOLUTIONS
A method for the extraction of vanadium (V) from acidic mixtures containing fluoride comprising effecting the extraction with amines in a water-immiscible organic solvent, the vanadium being...
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3723606 |
PRODUCTION OF PHOSPHORIC ACID
Phosphate rock is reacted with hydrochloric acid in the presence of a water-soluble sodium compound to produce an aqueous acidulate containing phosphoric acid. The aqueous acidulate is extracted...
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3720755 |
PROCESS FOR PREPARING A SOLUTION CONTAINING HYDROXYL AMMONIUM PHOSPHATE
A process for preparing a solution of hydroxylammonium phosphate which includes catalytic reduction of nitrate ions in an aqueous solution containing phosphoric acid using molecular hydrogen. In...
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3718729 |
DEFLUORINATION OF WET PROCESS PHOSPHORIC ACID
A process for the defluorination of phosphoric acid containing dissolved aluminum is described.
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3714330 |
TREATMENT OF PHOSPHORIC ACID TO RECOVER ALKALI METAL FLUOSILICATES
Alkali fluosilicates can be recovered from wet process phosphoric acid without contaminating the acid with additional anions, by reacting phosphoric acid with an alkali metal salt, such as sodium...
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3645682 |
A PROCESS FOR PRODUCING PHOSPHORIC ACID BY THE USE OF ION EXCHANGE RESINS
The invention relates to an improved method of ion exchange. The inventive concept involves directly contacting a substantially dry ion exchange resin with a substantially dry material which...
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3644091 |
CLARIFICATION OF PHOSPHORIC ACID
Phosphoric acid in a wet phosphoric acid process is clarified by introducing into the acid a small but effective amount of a clarification additive which is a sulfonated polystyrene or a water...
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3642439 |
METHOD OF SEPARATING MAGNESIUM FROM WET-PROCESS PHOSPHORIC ACID
A method of separating magnesium from wet-process phosphoric acid characterized in that the magnesium is separated as a readily filterable fluoride-phosphate complex compound containing magnesium...
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3637348 |
CONTROL OF POSTPRECIPITATION FROM WET PROCESS PHOSPHORIC ACID
This invention is directed to controlling the rate and amount of postprecipitate that forms in merchant grade phosphoric acid by treating the acid with cresylic acid, picoline, pyridine and their...
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3632311 |
SEPARATION OF PHOSPHOROUS ACID FROM MIXTURES OF PHOSPHOROUS ACID AND PHOSPHORIC ACID BY AMINE EXTRACTION
Disclosed herein is a process for separating phosphorous acid (H 3 PO 4 from mixtures of phosphorous and phosphoric acid (H 3 PO 4 ). An aqueous solution of the acids is mixed with a solvent...
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3615195 |
FLUOSILIC ACID RECOVERY
This disclosure is concerned with a process whereby fluorine values in the form of fluosilicic acid may be effectively and economically recovered from dilute phosphoric acid wash solutions obtained...
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3607031 |
PROCESS FOR PURIFYING AND CONCENTRATING AQUEOUS SOLUTIONS OF PHOSPHORIC ACID
A process for purifying and concentrating aqueous solutions of phosphoric acid which comprises: A. mixing an aqueous solution having a P 2 O 5 content lower than 25 percent by weight and a...
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3607029 |
CONTINUOUS PROCESS FOR SOLVENT PURIFICATION OF PHOSPHORIC ACID
The process for extraction and purification of phosphoric acid from impure solutions of phosphoric acid derived by acid attack of phosphate rock wherein the impure solution is first passed in...
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3544269 |
METHOD FOR PRODUCING DEFLUORINATED PHOSPHORIC ACID
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3529932 |
PROCESS FOR REMOVING TITANIUM FROM TITANIUM-CONTAINING PHOSPHORIC ACID
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3528771 |
PHOSPHORIC ACID CLARIFICATION
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3522833 |
PRODUCTION OF PHOSPHORIC ACIDS
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3506394 |
METHOD FOR PRODUCING SODIUM SILICOFLUORIDE FROM WET PROCESS PHOSPHORIC ACID
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3506397 |
PHOSPHORIC ACID RECOVERY FROM SPENT PLASTIC CONDITIONER SOLUTION
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3506398 |
PURIFICATION OF PHOSPHATE VALUES WITH RESPECT TO IRON
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3499729 |
MANUFACTURE OF PHOSPHORIC ACID
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3498746 |
RECOVERY OF FLUOSILICIC ACID AND P2O5 FROM RECYCLE STREAMS AND POND WATER
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3497330 |
SOLVENT EXTRACTION OF IRON FROM PHOSPHORIC ACID
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