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4806324 |
Process for making phosphoric acid free from titanium
Phosphoric acid substantially free from titanium is made from the organic extract obtained by subjecting crude phosphoric acid containing titanium to extractive purification with an organic solvent...
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4806323 |
Method for the removal of cadmium from acid phosphate-containing aqueous media
Cadmium is removed from an acid, phosphate-containing aqueous medium with the aid of an anion exchanger, in which process, during the removal, iodide or bromide ions are present in a quantity of...
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4804526 |
Process for purifying phosphoric acid for electrical semiconductor use
Phosphoric acid is treated to remove and/or tie up heavy metals and antimony to enable the acid to be used in electrical semiconductor applications by reacting the acid with hydrogen sulfide and...
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4800071 |
Filtration aids for removal of calcium solids from aqueous phosphoric acid
Separation of gypsum from phosphoric acid liquor produced during the production of phosphoric acid from finely ground phosphate rock. These aids are characterized as containing sulfonate and...
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4780294 |
Process for making crude phosphoric acid
Crude phosphoric acid is made by subjecting crude phosphate ore containing sulfide to processing treatment with a mineral acid in a closed system comprised of a processing reactor, a filtering zone...
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4780295 |
Process for purifying phosphoric acid
The invention is a process to purify a solution of phosphoric acid by removing transition metal impurities such as iron, chromium and vanadium. In the process a solution of phosphoric acid in an...
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4777028 |
Process for freeing mineral acids from heavy metals
Mineral acids are freed from heavy metals, especially copper, arsenic, antimony and lead by precipitating the metals in sulfide form. To this end, the mineral acid is reacted with hydrogen sulfide...
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4769226 |
Purification of wet-process phosphoric acid
Crude wet-process phosphoric acid is purified by treating a dilute such acid with a molybdenum value reducing amount of hydrogen sulfide or of a sulfide which in situ forms hydrogen sulfide, to...
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4762698 |
Method for increasing fluosilicic acid recovered from wet process phosphoric acid production
A method is disclosed for increasing the fluosilicic acid (FSA) recovered from a wet process phosphoric acid manufacturing process. The filtrate obtained by washing a filter cake is pumped to a...
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4762692 |
Process for the precipitation and separation of cadmium sulphide from the raffinates derived from phosphoric acid purification
Disclosed is a process for the precipitation and separation of cadmium sulphide from the raffinates derived from phosphoric acid purification by treating the cadmium containing streams of the...
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4721519 |
Stable ammonium polyphosphate liquid fertilizer from merchant grade phosphoric acid
A stable ammonium polyphosphate liquid fertilizer is prepared from concentrated wet-process phosphoric acid of 54-62% P 2 O 5 , which prior to concentration is treated with a cation exchange resin...
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4713229 |
Process for purifying phosphoric acid
Wet process phosphoric acid is freed from heavy metal ions, especially from ions of cadmium, copper, mercury, lead and arsenic and optionally also from organic compounds and sulfuric acid. To this...
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4710366 |
Method for producing stabilized wet process phosphoric acid with low content of magnesium and aluminum
Wet process phosphoric acid, stabilized with respect to the precipitation of solids upon aging, and containing significantly reduced levels of magnesium and aluminum, is prepared by the controlled...
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4705671 |
Apparatus for reducing iron and vanadium in phosphoric acid solution
Apparatus for reducing iron and vanadium in phosphoric acid solution with the aid of a granular reductant. The apparatus is comprised of a drum rotatable around its transverse axis. It is partially...
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4698163 |
Treatment of phosphate-containing wastewater
A method is provided for treating contaminated wastewater of pH ranging from about 1.5 to 3 containing phosphate ions and fluoride ions. The method comprises treating the said wastewater with an...
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4692323 |
Process for separation of magnesium-based, and possibly fluorine-and aluminum-based impurities from a wet-produced phosphoric acid
The invention concerns a process for separating magnesium-based impurities contained in a wet-process produced phosphoric acid. This process comprises adding an ammonium compound R(NH 4 ) soluble...
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4684512 |
Phosphate recovery from wet phosphoric acid purification process
The invention is a process for recovering phosphorus value from magnesium pyrophosphate containing filter media in the wet superphosphoric acid purification process. The invention comprises...
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4683127 |
Process for making wet-process phosphoric acid
Wet-process phosphoric acid is made by subjecting a phosphate ore to processing treatment with a mineral acid resulting in the formation of a processed suspension. The formation of silicofluorides...
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4670244 |
Process for reducing metal ions in aqueous solutions
Metal ions are reduced from a higher to a lower oxidation stage using ferrophosphorus as the reductant.
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4668492 |
Process for dearsenifying phosphoric acid solutions
Phosphoric acid solutions are dearsenified by treating them with a sulfide and separating the resulting precipitate from the purified solution. The sulfide is at least one compound of the general...
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4657559 |
Process for seed crystal preparation for phosphoric acid crystallization
The present invention relates to the processing of phosphoric acid by crystallization starting with phosphoric acid and adding relatively large amounts of fine, relatively pure seed crystals to...
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4657680 |
Wastewater treatment
A method is provided for the treatment of wastewater of pH ranging from about 1.5 to 3 containing at least about 100 ppm phosphorus as phosphate ions, at least about 50 ppm fluorine as fluoride...
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4656012 |
Process for the recovery of uranium from phosphoric acid solutions
The invention concerns the recovery of heavy metals from concentrated solutions. The process comprises complexing the metals with an organophosphorous complexing agent and recovering the metallic...
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4655790 |
Phosphoric acid crystallization process
The present invention relates to the processing of phosphoric acid by crystallization. Wet-process phosphoric acid is purified by cooling it to supersaturated conditions and adding relatively large...
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4652380 |
Method of treating the arsenic containing filter media from phosphoric acid purification
Filter cake waste media from a phosphoric acid purification process containing contaminating amounts of arsenic is treated in the process of this invention to remove the arsenic therefrom and to...
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4643883 |
Method of decolorizing wet process phosphoric acid
A method of decolorizing wet process phosphoric acid containing organic color-imparting impurities is provided. The process includes treating the acid with a strong oxidant at a temperature in the...
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4642224 |
Process for reducing iron and vanadium in phosphoric acid solution
Iron and vanadium is phosphoric acid solution are reduced. To this end, the phosphoric acid solution is contacted with ferrophosphorus which is used as the reductant.
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4640828 |
Separation of dissolved substances from wet process phosphoric acid
A process for separating and removing substantial amounts of magnesium and other ion impurities from wet process phosphoric acid of 35-45% P 2 O 5 content is provided. The process steps comprise:...
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4639359 |
Process of removing cationic impurities from wet process phosphoric acid
A method of removing aluminum, magnesium, iron and other impurities from wet process phosphoric acid is provided. The method comprises partially ammoniating the acid and reacting the acid with a...
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4637921 |
Process for producing ammonium polyphosphate
An improved process of concentrating wet process phosphoric acid by continuously contacting an acid feed containing at least about 56 weight percent of P 2 O 5 based on the total weight of the...
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4637922 |
Method for removing organic materials from a wet process phosphoric acid
A method for removing organic materials from a wet process phosphoric acid obtained by treating an uncalcined phosphate rock with sulfuric acid. The wet process phosphoric acid is contacted with a...
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4636372 |
Aluminum fluorophosphates made from impure phosphoric acids and conversion thereof to alkalimetal phosphates
Alkali metal phosphates and HF can be produced from a substantially calcium-free fluoroaluminum phosphate precipitate (which also contains iron) made by the aging of wet process phosphoric acid...
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4634580 |
Process for the purification of wet-process phosphoric acid by removal of cadmium
A process for the removal of cadmium contained in wet-process phosphoric acid by flotation by means of a cadmium-collector anionic surface active agent and an injected gas in the presence of other...
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4632814 |
Process for stabilizing phosphoric acid
An improved process for stabilizing wet process phosphoric acid is described in which the acid is treated with pressurized carbon dioxide and then is aged so as to enhance the rate of...
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4632812 |
Process for making alkali metal phosphate solutions containing little vanadium
Alkali metal phosphate solutions containing little vanadium are made from phosphoric acid containing vanadium. To this end, a negative redox potential is established in the phosphoric acid by...
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4629614 |
Process for decontaminating phosphoric acid
Wet-process phosphoric acid prepurified by liquid/liquid extraction with an organic solvent is decontaminated. To this end, the prepurified acid is first freed from residual extractant, then...
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4619819 |
Phosphoric acid composition
Processes and compositions of matter are disclosed for the production of liquid fertilizers wherein wastewater from a phosphorus smelting furnace is incorporated in liquid fertilizer processes. The...
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4596703 |
Process for purifying wet-processed phosphoric acid
The disclosure relates to a process for purifying crude, concentrated wet-processed phosphoric acid. To this end, the disclosure provides: (a) for the organic solvent to be mixed with the...
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4592901 |
Method of removing suspended solids from phosphoric acid
A process for removing impurities from phosphoric acid, especially concentrated wet process phosphoric acid, comprises filtering phosphoric acid through a filter cake (e.g., diatomite) on a porous...
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4588570 |
Method for the preparation of phosphoric acid and calcium sulphate
The present invention provides a continuous method for preparing phosphoric acid and calcium sulphate by reacting calcium phosphate with a mixture of sulphuric acid and phosphoric acid. Our method...
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4585636 |
Process for the manufacture of purified phosphoric acid
The present invention relates to an improved process for the manufacture of purified phosphoric acid from phosphate rock. According to the invention, phosphate rock is decomposed by a mineral acid...
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4565680 |
Recovery of phosphorus and aluminum from spent acid from the bright-dip aluminum finishing process
In the process of the invention spent phosphoric acid is concentrated and stripped with air to a greater than 50% P 2 O 5 concentration to remove nitric acid. As a result of concentrating the...
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4559204 |
Treatment of phosphate ore used in preparing phosphate matrix slurries
There is disclosed a method of producing water-based phosphate matrix slurries wherein the as-mined phosphate matrix is dried prior to the formation of the slurry. Drying the matrix decreases the...
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4557748 |
Method of lowering the magnesium impurity level of wet-process phosphoric acid during production of liquid fertilizer
A process for treating wet-process weak phosphoric acid solution is disclosed which significantly lowers the magnesium impurities in the acid (as well as certain other impurities) permitting...
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4554144 |
Removal of magnesium and/or aluminum values from impure aqueous phosphoric acid
Magnesium and aluminum impurities are removed from aqueous phosphoric acid by treatment with a fluorine material and an alkali metal containing material in such a manner that the atomic ratio of...
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4551320 |
Treatment of concentrated phosphoric acid
The calcium content of high purity concentrated phosphoric acid is reduced to not more than about 2 ppm by contacting the acid with a strong cation exchange resin.
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4551319 |
Two-stage concentration for superphosphoric acid
A process for the concentration of phosphoric acid by evaporation under vacuum in two stages to produce superphosphoric acid, the pressure inside the exchanger is kept equal to or greater than 0.35...
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4547295 |
Filtration of wet process superphosphoric acid
Filtration of wet process superphosphoric acid by vacuum filtration is greatly enhanced by the use of a filter aid having a statistically selected distribution of particle sizes.
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4545788 |
Process and apparatus for discharging and degassing a slurry from an attack tank
A slurry is discharged from an attack tank and degassed. At the top of the tank there is an overflow for discharging a first slurry portion. A container communicates with a pump. A receptacle is...
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4540558 |
Process for removing organic contaminants from wet-processed phosphoric acid
The disclosure relates to a process for removing organic compounds from wet-processed phosphoric acid with the aid of an adsorbant. To this end the disclosure provides for the acid to be heated to...
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