Class 423/340 - By purifying sand

Subclass of Class 423 - Chemistry of inorganic compounds
Definition: Processes which include the step of purifying silicon dioxide.
No. of patents: 38
Last issue date: 11/13/2007

Number	Title	Issue Date
7293568	Aqueous solutions of silicon metal and methods of making and using same The present invention generally relates to a formulation created by reacting sodium hydroxide, water, and silicon metal which has unique properties and many uses. The instant invention is further directed to methods of producing and using such formulations. ...	11/13/2007
7101524	Process for purifying sand A process for removing iron impurities from sand by treatment of an aqueous slurry of the sand with a chelating agent for iron cations. ...	09/05/2006
6746655	Method for purifying SiO2-particles In a known method for the cleaning of SiO2 grain, a fill of particles in a reactor having a vertically oriented center axis will be heated and simultaneously exposed to a treatment gas which is passed at a specified flow velocity from the bottom to the to...	06/08/2004
6537796	Conversion of geothermal waste to commercial products including silica A process for the treatment of geothermal residue includes contacting the pigmented amorphous silica-containing component with a depigmenting reagent one or more times to depigment the silica and produce a mixture containing depigmented amorphous silica a...	03/25/2003
6409978	Method of removing impurities from mineral concentrates A process for removing impurities contained in the crystal lattice of minerals, comprising the steps of forming a mixture of a mineral capable of structurally reorganizing its crystal lattice which contains an impurity in its crystal lattice and a halogen...	06/25/2002
6277349	Tridymite-based processing for high purity quartz A process of purifying crystalline quartz to remove impurities within the lattice structure comprising the steps of heating the quartz to the tridymite polymorphic form and evaporatively reacting the heated quartz with an aqueous acid solution reactive wi...	08/21/2001
6180077	Process for purification of SiO2 granulate A process for the purification of SiO2 granulate is provided, where the SiO2 granulate is supplied into a reaction zone, heated therein and exposed to a treatment gas which comprises a halogen-containing component. The treatment gas ...	01/30/2001
6090353	Method of removing impurities from mineral concentrates A process for removing impurities contained in the crystal lattice of minerals, comprising the steps of forming a mixture of a mineral capable of structurally reorganizing its crystal lattice which contains an impurity in its crystal lattice and a halogen...	07/18/2000
5853685	Process for the production of high purity silica from waste by-product silica and hydrogen fluoride High purity silica is obtained by the reaction of impure by-product waste silica with hydrogen fluoride preferably in the presence of water or sulfuric acid, producing silicon tetrafluoride gas and a mother liquor. The silicon tetrafluoride is separated f...	12/29/1998
5780005	Method for manufacturing spherical silica from olivine In a method for manufacturing silica a leaching of natural silicates is performed with hydrochloric acid or other mineral acids, draining, drying and possibly a grinding up of the residue of the product obtained. In order to obtain a spherical silica with...	07/14/1998
5637284	Process for continuous refining of quartz powder A rotating cylindrical quartz glass tube is partitioned into at least 3 chambers comprising a pre-heating chamber, a reaction chamber, and a gas desorption chamber. The process comprises pre-heating the starting quartz powder by continuously supplying it ...	06/10/1997
5445804	Process for the manufacture of pure amorphous silica from rocks A process for the manufacture of pure amorphous silica from rocks containing non-crystalline silica is described. The process comprises the steps of: (a) dissolution of said rock in an alkaline solution comprising sodium hydroxide and sodium carbonate, ob...	08/29/1995
5411149	Aqueous biphasic extraction process with pH and particle control A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica ...	05/02/1995
5334364	Process for purifying silica sand A process for the elimination of iron from silica sand, comprising: abrasive-attritioning sand particles by subjecting the sand particles, in a single step and under dry conditions, to centrifugal rotation and simultaneously imparting an agitation with a ...	08/02/1994
5302364	Process for the preparation of amorphous silica The invention provides a process for the production of a high grade amorphous silica having a purity of at least 90% active silica of the formula SiO2.nH.sub.2 O, comprising the steps of: a. comminuting and wet classification of porcellanite rock to...	04/12/1994
5202104	Process for preparing silica having a low silanol content A process for preparing silica having a low silanol content which comprises heating amorphous silica in an atmosphere of a low partial pressure of water vapor to maintain the amorphous silica at a temperature in a range of from 600° to 1000° C. at a fir...	04/13/1993
5102837	Process for the preparation of opaliform porcellanite The present invention provides high grade opaliform porcellanite having a purity of at least 80% active silica. The invention also provides a process for the production of a high grade opaliform porcellanite having a purity of at least 80% active silica c...	04/07/1992
5080721	Process for cleaning particulate solids A system for cleaning solids contaminated with solvent-soluble contaminants. The system, which includes both process and apparatus, comprises the use of at least two successive cleaning zones, each of which includes a slurrying stage and a centrifuge sepa...	01/14/1992
5037625	Purified quartz and process for purifying quartz Quartz is purified by removing mineral impurities, particularly alkali metal impurities, from within the quartz crystal lattice structure. According to the disclosed process, quartz crystals are subjected to a pretreatment that removes surface bound impur...	08/06/1991
5024740	Mineral refinement by high RF energy application A method and apparatus for the elimination of unwanted impurities and inclusions from a variety of non-conductive base materials by the application of high power, variable frequency RF energies in selective of rarefied atmospheres. Refined natural quartz ...	06/18/1991
4983370	Purified quartz and process for purifying quartz Quartz is purified by removing mineral impurities, particularly alkali metal impurities, from within the quartz crystal lattice structure. According to the disclosed process, quartz crystals are subjected to a pretreatment that removes surface bound impur...	01/08/1991
4956059	Process for the purification of granular silicon dioxide Granular silicon dioxide is placed in a treatment chamber which is heated to a temperature ranging from 700° to 1300° C. The chamber is then rotated for a prescribed period of time to mix the grains while a gaseous atmosphere of chlorine and/or hydrogen...	09/11/1990
4952246	Plant and method for reconditioning green foundry sand Green sand having a residuum of retained clay is reconditioned by screening and predrying it to about zero moisture; calcining the sand to burn off organic matter; cooling the sand; mechanically scrubbing the cooled sand to free mechanically bonded clay a...	08/28/1990
4818510	Modified close fraction batch process for purification of SiO₂ The disclosed process separates impurities, including admixed minerals other than quartz and quartz particles having relatively high levels of lattice impurities, from a quartz containing particulate material to recover a high purity quartz product. The p...	04/04/1989
4804422	Method of purifying quartz sand Starting from pegmatitic sand, the invention provides a method of purifying quartz sand, in which the amount of iron is reduced to less than 0.3 ppm, the amount of zircon to less than 1 ppm, and the amount of phosphor to less than 0.2 ppm. Gas nuclei are ...	02/14/1989
4710367	Process for reducing the concentration of heavy metals in geothermal brine sludge A process is provided for reducing the total concentration of heavy metals, notably lead, copper and zinc, naturally occurring in silica-rich sludge precipitated from geothermal brine in a brine handling system such as a geothermal brine electric generati...	12/01/1987
4683128	Process for manufacturing high purity silica This invention deals with a process for manufacturing high purity silica which comprises making an aqueous alkali silicate solution into fine fibrous gel in a coagulant, treating the fibrous gel obtained with an acid-containing solution, and then with wat...	07/28/1987
4676964	Process for purifying silica This invention concerns a process for purifying silica produced from an alkali silicate aqueous solution, which usually contains more than 200 ppm of impurities, to silica containing less than 30 ppm of impurities. Concretely, the purification process of ...	06/30/1987
4557918	Method for producing silica The present invention relates to a method for purifying silica waste obtained in the manufacture of aluminium fluoride from hexafluosilicic acid and aluminium hydroxide, whereby the silica, is subjected to an acidic leaching at a pH below 3 to leach out p...	12/10/1985
4542003	Chemical treatment of sand A process for treating sand which includes one or more stages in which sand is mixed with a dilute aqueous solution of hydrofluoric or sulphuric acid together with zinc or sodium hydrosulphite and the resulting slurry is agitated at ambient temperature in...	09/17/1985
4405588	Process of removing iron impurities from ores A process of removing iron impurities from ores, particularly useful for removing stains of iron impurities adhered to silica sand particles, comprises grinding the ore, washing and desliming the ground ore to remove the major part of the clay-type binder...	09/20/1983
4401638	Process for purifying silica sand A process of purifying silica sand comprises grinding sandstone, washing and desliming the ground sandstone to remove the major part of the clay-type binder, attrition-scrubbing the deslimed sand particles to release further amounts of binder therefrom, w...	08/30/1983
4294811	Process for manufacturing Si useful for semiconductor components from quartz sand Relatively pure Si (having less than about 1 ppm of detrimental impurities therein) is obtained from ordinary quartz sand by uniformly admixing such sand with suitable glass-forming materials, such as boron oxide and alkali-metal carbonates or oxides, mel...	10/13/1981
4264564	Process for the manufacture of high purity silicic acid A process is herein described for the manufacture of high purity, granular silicic acid from aqueous alkali metal silicate solutions by acidification thereof, freezing and subsequently thawing the reaction mixture, and filtering, washing and drying the in...	04/28/1981
4200485	Method for making high purity, devitrification resistant, amorphous silica fibers This invention involves a method of making high purity amorphous silica fibers having excellent resistance to devitrification by double leaching sodium silicate type fibers....	04/29/1980
4042671	Process for leaching sand or other particulate material A process for leaching sand to remove iron and other undesirable components in which the sand is treated with a series of leaching solutions which increase in acid concentration to about the midpoint of the process followed by decrease in concentration to...	08/16/1977
4040795	Method for the conversion of crystalline silica raw materials into amorphous silica The apparatus is a rotatable resistance heating furnace including a rotatable cylindrical body portion having an interior space in the form of a truncated cone. The base of the truncated cone forms a discharge opening for rapid discharge of the amorphous ...	08/09/1977
4010098	Resource recovery from disposal of solid waste and sewage sludge The treatment of solid waste and sewage sludge with the recovery of natural resources comprising subjecting all or at least a portion of the sewage sludge to wet oxidation reaction to reduce the COD by an amount of at least 50% and preferably 50-85% and u...	03/01/1977

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Class 423/340 - By purifying sand