Abstract: Fe(III) complexes having high bulk density and a process for the production of the same without the generation of heavy metal-contaminated effluents are disclosed. Solid complexes of EDTANaFe and EDTAKFe having high bulk densities are formed by reaction with ferric sulfate containing low chromium levels, followed by total drying of the resulting mixture in the same processing equipment without the prior separation of the sulfate salts formed.
Abstract: There is provided a vacancy titanate intercalated with a cationic hydroxy aluminum complex, such as Keggin ion. A method for making this material and a process for using this material as a catalyst are also provided.
Abstract: Process for the manufacture of a powder of mixed metal oxides by cohydrolysis of metal alcoholates in the presence of an acidic organic compound and mixed metal oxide powders in which the molar relationships R1 and R2 of a metal oxide to the sum of the metal oxides in the powder and in a particle of the powder are such that ##EQU1## The process applies especially well to powders of zirconia doped with yttrium oxide or other oxides.
Type:
Grant
Filed:
May 20, 1991
Date of Patent:
October 6, 1992
Assignee:
Solvay S.A.
Inventors:
Franz Legrand, Luc Lerot, Patricia De Bruycker
Abstract: A method for manufacturing a precursor powder for use in making a varistor is disclosed. This precursor powder is produced by preparing a homogeneous aqueous dispersion of metal oxides and/or metal hydroxides and heating the dispersion in a closed pressure reactor to a temperature between 200.degree. C. and 350.degree. C. for hydrothermally treating the homogeneous dispersion. The precursor powder produced in the afore-described method is highly homogeneous and of controlled crystal phase and morphology and after mixing with zinc oxide powder can homogeneously be reacted with the zinc oxide in a ceramic process.
Type:
Grant
Filed:
December 5, 1989
Date of Patent:
September 1, 1992
Assignee:
Asea Brown Boveri Ltd.
Inventors:
Wolfgang Kluge, Roger Perkins, Marco Rossinelli, William J. Dawson
Abstract: From an ore containing gold and silver, the gold and silver are extracted by a method which comprises pulverizing the ore and bringing the pulverized ore into contact with an elemental halogen, a halogenated salt, and an organic solvent thereby converting the gold and silver into polyhalogeno anionic complexes and consequently dissolving them in the organic solvent.
Type:
Grant
Filed:
August 1, 1991
Date of Patent:
August 18, 1992
Assignees:
Agency of Industrial Science and Technology, Ministry of International Trade and Industry
Abstract: Method is described for the low temperature preparation of the spinel LiMn.sub.2 O.sub.4 phase which is an intercalable compound of interest for use in lithium secondary batteries. This phase can be prepared in bulk or thick film form at temperatures less than 400.degree. C. using acetate precursors.
Type:
Grant
Filed:
April 23, 1991
Date of Patent:
August 4, 1992
Assignee:
Bell Communications Research, Inc.
Inventors:
Philippe Barboux, Frough K. Shokoohi, Jean-Marie Tarascon
Abstract: The present invention relates to a method for the preparation of ultrafine oxide particles using organized reaction media. Integrated circuit (IC) densities have necessitated the use of ultrahigh purity process fluids in state of the art fabrication facilities. It is the purpose of the present invention to synthesize monodispersed submicron particles of some representative contaminants, such as ultrafine oxide particles, using organized reaction media, and study their characteristics in relation to their removal from process fluids.
Type:
Grant
Filed:
December 22, 1988
Date of Patent:
July 28, 1992
Assignee:
Arizona Technology Development Corporation
Inventors:
Srini Raghavan, Subhash H. Risbud, Pradeep P. Phule
Abstract: Cobalt is recovered from the oil/water mixed reaction product of oxonation by increasing the carbon dioxide level in the reaction product and adjusting the temperature to enhance the carbon dioxide level in the oil water phase to promote the formation of cobalt carbonate which is allowed to settle and may be removed and/or recycled increasing cobalt utilization and reducing environmental problems.
Type:
Grant
Filed:
December 21, 1990
Date of Patent:
July 14, 1992
Assignee:
Exxon Chemical Patents Inc.
Inventors:
Nicolaas A. De Munck, Mattheus D. Olijve, Raf Caers, Arie Van Vliet, Jean A. A. Hanin, Eddy Van Driessche
Abstract: Alkali metal phosphate solutions having a fluorine content of less than 20 ppm, based on P.sub.2 O.sub.5, are prepared by first digesting crude phosphate using sulfuric acid, and separating the calcium sulfate from the crude phosphoric acid. An alkali metal compound is then added to the crude phosphoric acid, and the precipitated solid is filtered off. The prepurified crude phosphoric acid is neutralized to a pH of at least 7, and the solid produced during this operation is separated off. The resultant alkali metal phosphate solutions having a P.sub.2 O.sub.5 content of from 10 to 30% by weight are adjusted to a pH of between 4.8 and 6.0 using phosphoric acid. The solutions are heated to from 60.degree. to 120.degree. C., and from 1 to 6% by weight, based on the weight of the solution, of an alkaline earth metal oxygen compound are added to the alkali metal phosphate solutions with stirring.
Type:
Grant
Filed:
March 28, 1991
Date of Patent:
June 23, 1992
Assignee:
Hoechst Aktiengesellschaft
Inventors:
Gunther Schimmel, Thomas Staffel, Reinhard Gradl
Abstract: A method is described for mixing a difficult to wet, finely divided powder, e.g. alumina dust, with an aqueous liquid, e.g. Bayer process spent liquor. In the method, the liquor is introduced into a cylindrical mixing zone having a conical bottom zone, the liquor being continuously introduced into the mixing zone as a high velocity stream tangentially immediately above the conical zone to thereby form a rapidly moving vortex within the mixing zone. The dust is caused to fall into the center of the vortex whereby the dust is rapidly engulfed by the liquor with little or no dusting. The thus formed slurry is continuously removed from the bottom of the conical zone and may be processed through a classification circuit, to be separated as fine seed and returned to the precipitation circuit where the fine particles are agglomerated and grown to larger particles of alumina by contact with Bayer process pregnant liquor.
Type:
Grant
Filed:
January 9, 1991
Date of Patent:
June 16, 1992
Assignee:
Alcan International Limited
Inventors:
Winston V. St. Elmo Spence, Peter B. Lukong
Abstract: Fermentors, reactors and processes for preparing magnesium enriched calcium magnesium acetate (CMA) (Mg:Ca mole ratios of 1:1 to 20:1) by reacting a dolomitic lime product with a Mg:Ca mole ratio less than one with dilute acetic acid, such as in fermentation broths. A process to prepare a mildly aklaline mineral product by calcining the dolomite under conditions to convert only the MgCO.sub.3 to MgO and treating the selectively calcined dolomite with acidic solutions to dissolve largely the MgO, leaving the original CaCO.sub.3 matrix intact. The mildly alkaline mineral product includes a highly porous structure derived from dolomite, consisting of a matrix of CaCO.sub.3 with smaller amounts of MgO and interspersed with a regular array of voids on a molecular scale.
Abstract: A process is described for removing dissolved silica from process solutions or slurries formed in the Bayer process for producing alumina from bauxite. In the novel process, a Bayer process solution or slurry is contacted with porous agglomerates of a material containing Bayer process desilication product and bonded together by a polymer resin which is resistant to chemical degradation by high concentrations of caustic present in Bayer process liquors. The desilication product is essentially complex hydrated sodium aluminum silicates and typical bonding resins are polyvinylchloride or polypropylene.
Abstract: This invention is directed to the formation of homogeneous, aqueous precursor mixtures of at least one substantially soluble metal salt and a substantially soluble, combustible co-reactant compound, typically an amino acid. This produces, upon evaporation, a substantially homogeneous intermediate material having a total solids level which would support combustion. The homogeneous intermediate material essentially comprises highly dispersed or solvated metal constituents and the co-reactant compound. The intermediate material is quite flammable. A metal oxide powder results on ignition of the intermediate product which combusts same to produce the product powder.
Type:
Grant
Filed:
October 16, 1990
Date of Patent:
May 19, 1992
Assignee:
Battelle Memorial Institute
Inventors:
Larry R. Pederson, Lawrence A. Chick, Gregory J. Exarhos
Abstract: Gold and silver are extracted from their elemental state or from complex ores and alloys by leaching them with a solution containing ammonia, ammonium salts and one or more oxidants. The process is particularly effective for refractory gold ores including sulfide and carbonaceous ores.
Type:
Grant
Filed:
December 14, 1990
Date of Patent:
May 19, 1992
Assignee:
South Dakota School of Mines & Technology
Abstract: A method for producing a low abrasion calcined kaolin pigment which comprises forming an aqueous pulp of crude kaolin dispersing the pulp by adding thereto sufficient water-soluble organic cationic dispersant to impart a positive zeta potential to said particles and, preferably, an acidic pH to said pulp, removing coarse particles from said dispersed pulp and fractionating the dispersed pulp to separate a fine particle size fraction of mineral particles from coarser particles. The fine particle size fraction is dried, pulverized, calcined and repulverized.
Abstract: Potassium nitrate is produced by contacting nitric acid with a potassium loaded strong cationic exchange resin. In a preferred embodiment, a solution of potassium nitrate and dilute nitric acid is produced in a continuous liquid solid contacting apparatus. The preferred apparatus is formed of a plurality of resin filled chambers which rotate in and out of periodic fluid communication with fixed feed and discharge ports. The apparatus design allows for continuous supply of a nitric acid solution, potassium chloride regeneration solution, wash solutions, and air streams to ports arranged in zones, so that resin filled chambers pass through the zones to continuously produce a solution containing potassium nitrate and dilute nitric acid. In a preferred embodiment, the solution of potassium nitrate produced is neutralized with potassium hydroxide to convert residual nitric acid to potassium nitrate.
Abstract: A magnesium oxide in fine powder form, which can be used to manufacture high-density ceramics, has an MgO content greater than 95 wt. %, preferably greater than 98 wt. %, a particle size less than 15 .mu.m, and a BET specific surface area less than 20 m.sup.2 /g. The statistical mean of the particle shape factor of the primary particles lies between 1 and 1.5. The particles are coated with a hydrophobic, surface-active substance.
Abstract: Dipicolylamine (DPA) is chemically bound to the surface of a silicate, forming a solid phase particle without substantially decreasing the affinity constant of the DPA for certain ions. Then, the solid phase particle is contacted with the solution, thereby binding an ion to the particle. Subsequently the ion can be stripped from the ligand by treatment with a complexing agent or acid.
Abstract: A method for reducing impurity levels of calcium, magnesium and/or silicon in hexammine cobalt halide compounds involves the addition of ferric ions and, optionally, soluble fluorides to an aqueous hexammine cobalt (III) chloride solution having a pH of at least 9. Insoluble compounds of magnesium fluoride, calcium fluoride, and/or ferric hydroxide and silicon coprecipitates are removed from the solution by filtration.
Type:
Grant
Filed:
May 20, 1991
Date of Patent:
April 7, 1992
Assignee:
GTE Products Corporation
Inventors:
Eric F. Husted, Michael J. Miller, Shellie K. Northrop, David T. Smith