|
Match
|
Document |
Document Title |
|
|
4296082 |
Purification of wet process phosphoric acid
Wet process phosphoric acid is heated by passing alternating current through the acid, preferably in carbon apparatus to concentrations above 76% P 2 O 5 and preferably temperatures above 500°...
|
|
|
4294809 |
Aeration of phosphoric acid
Aeration of Hill phosphoric acid, preferably with perlite, and preferably with a chemical oxidant, e.g., H 2 O 2 . Gives good post-precipitation control with high-iron phosphate rock, even in...
|
|
|
4293311 |
Phosphoric acid crystallizer underflow return
In the Hill phosphoric acid process the crystallizer underflow is divided into a major stream and a minor stream. The major stream goes to the clarifier and the minor stream to the aluminum...
|
|
|
4291005 |
Settling out suspended solids in phosphoric acid product solutions
For settling suspended solids in phosphoric acid product solutions, a copolymer of 95 mole percent ammonium acrylate monomer, 5% acrylamide monomer is shown to remove more solids than prior art...
|
|
|
4284606 |
Extraction
A process as described for extracting at least two desired constituents from a mineral using a liquid reagent which produces the constituents, or compounds thereof, in separable form and...
|
|
|
4282192 |
Process for producing a calcium sulfate product containing low amounts of radium
Disclosed is a process for producing a calcium sulfate product containing low amounts of radium comprising the steps of: (a) adding at least one sequestering agent to a substantially homogeneous...
|
|
|
4279878 |
Process for freeing phosphoric acid from organic contaminants
The invention relates to a process for freeing aqueous phosphoric acid solutions from organic contaminants. To this end, the solutions are admixed and reacted with hydrogen peroxide in the presence...
|
|
|
4279877 |
Oxidative control of post precipitation in phosphoric acid
Improvement in the Hill phosphoric acid process. Fe + + in high iron feed is oxidized to Fe + ++ to improve post-precipitation characteristics, optionally, a minor stream from the crystallizer is...
|
|
|
4278648 |
Method of improving siliceous filter aid dispersion in wet process orthophosphoric acid production systems
A process is disclosed for improving the dispersability of siliceous (preferably diatomite) filter aid particles in hot (i.e., 140° F. or higher) aqueous acid systems used in the "wet process"...
|
|
|
4264563 |
Preparation of calcium fluoride from fluosilicic acid solutions
A fluosilicate material is added to a suspension of lime in water heated to a temperature at or near its boiling point to form a solid calcium fluoride product in which the silicon present in the...
|
|
|
4263148 |
Process for removing humic matter from phosphoric acid solutions
A process is disclosed for removing colloidal and non-colloidal humic matter from an aqueous solution of phosphoric acid, the process comprising (a) treating the phosphoric acid solution with a...
|
|
|
4256570 |
Purification of phosphoric acid
Phosphoric acid is purified by a process which comprises treating the crude acid solution with a body feed agent and a flocculating agent to cause a portion of the impurities to settle out, and...
|
|
|
4250154 |
Re-post precipitation control
Prevention of re-post precipitation in concentrated wet process phosphoric acid by heating the acid at 55° to 85° C. thereby to dissolve solids without substantial re-post precipitation.
|
|
|
4248703 |
Emulsion removal from acidic solution-solvent interfaces
An emulsion, formed at the interface of an acidic solution and a solvent, is removed by passing at least one continuous belt through the emulsion by floating action, where portions of the emulsion...
|
|
|
4248843 |
Treatment of phosphoric acid
A method for the treatment of phosphoric acid containing one or more impurities comprising the ions of at least one of the metals from the group magnesium, iron and aluminium, including the step of...
|
|
|
4248846 |
Production of stabilized wet process phosphoric acid
This invention is directed to improvements in making wet process phosphoric acid substantially free from post-precipitation. The improvements include recycling to the reaction train a side stream...
|
|
|
4243643 |
Metallic ion removal from phosphoric acid
Metal ion impurities are removed from phosphoric acid by adding to the acid a precipitant comprising ions of calcium and fluorine to cause precipitation of a magnesium-containing precipitate. A...
|
|
|
4242198 |
Reduction of magnesium and other cations in phosphoric acid
Improvement in the reduction of Mg, Ca, Na, K and Al in crude phosphoric acid using an ion exchange resin bed, comprising preclarifying the feed acid with flocculant polymer and placing a filter...
|
|
|
4235854 |
Method for purifying wet process phosphoric acid
A method for removing impurities from wet process produced phosphoric acid and recovering phosphate values retained by the impurities is disclosed. The wet process produced phosphoric acid is...
|
|
|
4233278 |
Process for purifying crude phosphoric acid
Aqueous phosphoric acid, e.g., a slurry of the acid produced by the "wet" process, is contacted with steam under organic volatile-removing conditions to remove volatile organic material. A "wet...
|
|
|
4228140 |
Production of phosphates
Various stages of the process of producing phosphates are subject to a vacuum produced by a liquid ring pump in various materials of construction using relatively high concentrations of sulfuric...
|
|
|
4209497 |
Preparation of detergent grade sodium tripolyphosphate from wet process phosphoric acid and soda ash
A process for preparing detergent grade sodium tripolyphosphate from wet process phosphoric acid comprising neutralizing said acid to a pH at which the Na:P ratio is about 5:3, contacting the...
|
|
|
4207302 |
Method of treating phosphoric acid to prevent crud formation during solvent extraction
A method for pretreating phosphoric acid to prevent the formation of a mass of suspended solids (i.e., "crud") during solvent extraction of the acid is described. Prior to solvent extraction, the...
|
|
|
4196180 |
Purification of phosphoric acid by means of organic solvents
Contaminated phosphoric acid, particularly wet-processed phosphoric acid, is purified by extracting it from its aqueous solution by means of an organic solvent, which is immiscible or partially...
|
|
|
4191734 |
Fluoride-free phosphate reactions
Substantially fluoride-free phosphoric acid is produced by the acidulation of phosphate rock with sulfuric acid wherein the acidulation reaction is conducted in the presence of added potassium as K...
|
|
|
4178347 |
Process for the simultaneous production of wet process phosphoric acid and sodium silicofluoride
A process for recovering fluorine and silicon values from a waste-water stream produced in a wet-process phosphoric acid process which comprises: (a) diluting concentrated sulfuric acid with the...
|
|
|
4169881 |
Process for removing dissolved silica from extracted phosphoric acid
A method of purifying extracted phosphoric acid containing substantially no metallic impurities which comprises: (a) adjusting the phosphoric acid concentration to from 20 to 65 wt.% as P 2 O 5...
|
|
|
4169882 |
Purification of phosphoric acid with oxalic acid
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...
|
|
|
4152405 |
Co-current absorber for recovering inorganic compounds from plant effluents
Co-current absorber for recovering inorganic compounds from plant effluents, particularly useful for recovery of fluorine values as low phosphorus fluosilicic acid from phosphate plant effluents....
|
|
|
4147757 |
Method for producing ammonium phosphate which is substantially free of arsenic
A process for producing ammonium phosphate that is substantially free of arsenic which comprises: (a) reacting crude phosphoric acid containing dissolved arsenic having a +5 valence state with...
|
|
|
4146575 |
Preparation of sodium tripolyphosphate
The purity grade of sodium tripolyphosphate obtained by neutralization with sodium hydroxide of aqueous phosphoric acid obtained by the wet method, removal of the precipitate formed, evaporation to...
|
|
|
4134964 |
Process and apparatus for purifying wet-processed phosphoric acid
Process and apparatus for purifying crude wet-processed phosphoric acid containing free sulphuric acid. To this end, the wet-processed phosphoric acid is treated in a reaction zone, at a...
|
|
|
4134962 |
Production of pure alkali metal phosphate solutions from wet-processed phosphoric acids
Alkali metal phosphate solutions (alkali metal oxide : P 2 O 5 - molar ratio greater than 1.9 : 1) of reduced vanadium and chromium contents are made from wet-processed phosphoric acids which are...
|
|
|
4132765 |
Recovery of fluoride values
The fluoride values of fluorapatite ores can be recovered by using reactive metal compounds, e.g., the sulfates, phosphates or hydroxides of aluminum, iron, titanium, zirconium, antimony or...
|
|
|
4105748 |
Method of producing phosphoric acid and potassium dihydrogen phosphate from phosphate rock in the substantial absence of fluorine evolution
Substantially fluoride-free phosphoric acid is produced by the acidulation of phosphate rock with sulfuric acid wherein the acidulation reaction is conducted in the presence of added potassium as K...
|
|
|
T971006 |
Purification of phosphoric acid solutions
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...
|
|
|
4087512 |
Process for removing solid organic material from wet-process phosphoric acid
Wet-process phosphoric acid which is obtained by the acidulation of uncalcined phosphate rock with sulphuric acid and which typically contains 28-31% P 2 O 5 and measurable amounts of solid...
|
|
|
4083937 |
Process for preparing pure phosphoric acid
In a process for preparing a pure phosphoric acid whereby phosphate rock is treated with sulfuric acid or hydrochloric acid to prepare a crude phosphoric acid, and wherein said crude acid is...
|
|
|
4083934 |
Process for obtaining pure orthophosphoric acid from superphosphoric acid
A process for obtaining pure orthophosphoric acid from superphosphoric acid is provided comprising: (a) hydrolyzing superphosphoric acid with water until a mixture of polyphosphoric acids and...
|
|
|
4073635 |
Process for producing a slurry suitable for the manufacture of a mixed fertilizer containing nitrogen plus phosphorus
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...
|
|
|
4070443 |
Process for removing sulfate ions from extracted phosphoric acid with a barium compound
A process for removing sulfate ions from extracted phosphoric acid which is substantially free of metallic ion impurities and which has been prepared by extracting wet process phosphoric acid with...
|
|
|
4064220 |
Removal of dissolved organic matter from acidic aqueous solution
An aqueous solution of a mineral acid is freed of dissolved or colloidally dispersed organic matter by admixing to the solution an aldehyde or an aldehyde oligomer and a compound copolymerizable...
|
|
|
4060586 |
Recovery of fluorides from gypsum
In a process for the reaction of phosphate rock and sulfuric acid in the presence of potassium ion to form a mixture of phosphoric acid and a precipitated gypsum wherein the presence of the...
|
|
|
4055626 |
Method of producing fluoride-free phosphoric acid
Substantially fluoride-free phosphoric acid is produced by the acidulation of phosphate rock with sulfuric acid wherein the acidulation reaction is conducted in the presence of added potassium as K...
|
|
|
4053562 |
Production of alkali metal phosphate solutions of low vanadium content
Alkali metal phosphate solutions of low vanadium content are produced from wet-processed phosphoric acids contaminated with vanadium and iron. The acids containing vanadium and iron in the highest...
|
|
|
4053561 |
Removal of fluorine from phosphatic solutions
A method for removing fluoride ions from phosphoric acid by neutralizing said acid to a pH between about 5 and about 9, contacting the neutral salt solution thereby formed with an insoluble...
|
|
|
4048289 |
Stabilization of wet-process phosphoric acid
Impure wet-process phosphoric acid is stabilized against sludge formation by adding to a solution of said acid about 0.1 to 1% by weight of an inorganic oxidizing agent and about 0.1 to 1% by...
|
|
|
4046860 |
Ammonium fluoride process for defluorinating phosphoric acids and production of ammonium fluosilicate
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,...
|
|
|
4044108 |
Process for removing organic material from wet process phosphoric acid
A process for removing organic material from extracted phosphoric acid comprises contacting extracted phosphoric acid with a chlorate and hydrochloric acid at a temperature higher than 100° C...
|
|
|
4039624 |
Method of producing phosphoric acid from high iron and aluminum content phosphate rocks using nitric acid
This invention concerns the solubilization of phosphate values in phosphate bearing rock which contains high contents of aluminium and/or iron by attacking the phosphate rock with a nitric acid...
|