Patents Examined by Lori S. Freeman
  • Patent number: 4789537
    Abstract: A prealloyed metal catalyst is used to grow silicon carbide whiskers, especially in the .beta. form. Pretreating the metal particles to increase the weight percentages of carbon or silicon or both carbon and silicon allows whisker growth to begin immediately upon reaching growth temperature.
    Type: Grant
    Filed: June 25, 1987
    Date of Patent: December 6, 1988
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Peter D. Shalek, Joel D. Katz, George F. Hurley
  • Patent number: 4789421
    Abstract: A GaAs growth crystal comprises a Si substrate, an intermediate layer formed on the substrate and a GaAs layer grown on the intermediate layer. The intermediate layer includes constituent GaP/GaAsP and GaAsP/GaAs superlattice layers and additionally AlP and AlGaP thin films.
    Type: Grant
    Filed: September 27, 1985
    Date of Patent: December 6, 1988
    Assignee: Daidotokushuko Kabushikikaisha
    Inventors: Masayoshi Umeno, Shiro Sakai, Tetsuo Soga
  • Patent number: 4789530
    Abstract: A process for the preferential absorption of H.sub.2 S from a gas which contains H.sub.2 S and CO.sub.2 comprises contacting of the gas with a sorbent solution comprising alkali metal ethylenediaminetetraacetate and/or alkali metal nitrilotriacetate, in the substantial absence of oxidizing agents which can oxidize H.sub.2 S.
    Type: Grant
    Filed: December 9, 1987
    Date of Patent: December 6, 1988
    Assignee: Phillips Petroleum Company
    Inventors: Marvin M. Johnson, Ted H. Cymbaluk, Gerhard P. Nowack
  • Patent number: 4788049
    Abstract: A method is disclosed for producing silicon nitride wherein the crystal morphology is controlled. The method involves heating a mixture consisting essentially of a chlorosilane and ammonia at a sufficient temperature for a sufficient time to produce a nitogen containing silane as an intermediate. The bulk density of the intermediate is controlled to less than about 0.1 g/cc to result in the silicon nitride having a crystal morphology which is essentially all fibrous, or the bulk density can be controlled to greater than about 0.3 g/cc to result in the silicon nitride having a crystal morphology which is essentially all equiaxial, or the bulk density can be controlled to between about 0.1 g/cc and about 0.3 g/cc to result in the silicon nitride having a crystal morphology which is a mixture of fibrous and equiaxial. The intermediate is then heated at a sufficient temperature for a sufficient time in a non-oxidizing atmosphere to produce the controlled crystal morphology silicon nitride.
    Type: Grant
    Filed: March 21, 1986
    Date of Patent: November 29, 1988
    Assignee: GTE Products Corporation
    Inventors: Robert A. Long, Harrison Shallenberger, Dale E. Wittmer
  • Patent number: 4784840
    Abstract: Silicon of high purity is used in making semiconductor devices. Silicon for this purpose is made by decomposing silane in a fluidized bed reactor. This process entails thermal decomposition of silane to deposit additional metallic silicon on particles of high purity silicon. To obtain good process economics, two modes of operation are used. In a first mode, the reactor is operated under high productivity conditions which also result in co-production of silicon dust or fines. Some of the dust is deposited on the product silicon particles and some of it is elutriated by gas flow in the reactor and removed through an exit point near the top of the reactor apparatus. The dust on the particles can cause problems in handling. For example, in bagging the particles, or removing the particles from a bag, the dust can become airborne from the larger particle surfaces and form an objectionable cloud of silicon dust.
    Type: Grant
    Filed: October 28, 1987
    Date of Patent: November 15, 1988
    Assignee: Ethyl Corporation
    Inventors: Marcelian F. Gautreaux, Robert H. Allen
  • Patent number: 4781901
    Abstract: A method of removing hydrogen sulfide and carbon dioxide from a sour gaseous stream in a contact zone by contacting the sour gaseous stream with a lean CO.sub.2 -selective absorbent in an aqueous alkaline solution containing a polyvalent metal chelate at a pH of about 7 to about 10 wherein the polyvalent metal chelate is in one embodiment of the invention in the reduced or lower valence state in a contact zone and is oxidized to the oxidized or higher valence state in an oxidation zone so as to convert hydrosulfide and/or sulfide salts present in the contact zone to sulfur. In a second embodiment, the aqueous alkaline solution and CO.sub.2 -selective absorbent in contact with the gaseous stream is a mixture containing a higher valence polyvalent metal chelate together with a lower valence polyvalent metal chelate.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: November 1, 1988
    Assignee: The Dow Chemical Company
    Inventor: Gaines C. Jeffrey
  • Patent number: 4780297
    Abstract: Low structure magnesium silicate pigment is useful as a low cost, low brightness filler for newsprint. The magnesium silicate is prepared by dissolving a serpentine mineral in sulfuric acid and reacting the resulting solution with an alkali metal silicate to precipitate a magnesium silicate pigment.
    Type: Grant
    Filed: April 6, 1987
    Date of Patent: October 25, 1988
    Assignee: J. M. Huber Corporation
    Inventors: Leif B. Martensson, Kaarina Heikkila
  • Patent number: 4778668
    Abstract: Silicon halides and silicon hydrohalides, such as SiCl.sub.4, SiBr.sub.4, and SiHCl.sub.3 react with alkali metal aluminum hydrides such as NaAlH.sub.4 and LiAlH.sub.4 in the presence of a hydrocarbon reaction medium; e.g., toluene, and a tetraalkyl ammonium salt, and in the substantial absence of an ether, to produce silane and a metal aluminum halide co-product which is not tightly complexed to an organic substance.
    Type: Grant
    Filed: December 22, 1986
    Date of Patent: October 18, 1988
    Assignee: Ethyl Corporation
    Inventors: Everett M. Marlett, Robert N. DePriest
  • Patent number: 4778667
    Abstract: This invention relates to novel silica spheroids and to their production by a phase separation technique in which an aqueous alkaline stabilized silica sol and an aqueous solution of a non-adsorbing polymer are mixed and acidified to produce the new silica spheroids.
    Type: Grant
    Filed: December 2, 1986
    Date of Patent: October 18, 1988
    Assignee: Unilever Patent Holdings B.V.
    Inventors: Michael J. Garvey, Ian C. Griffiths
  • Patent number: 4775519
    Abstract: Improvement are provided in accordance with the present invention by a continuous process for the treating of a gas stream containing acid gas components wherein the gas stream is counter currently contacted in an absorption zone with an aqueous solution of a mixture of N-methyldiethanolamine with imidazole or a methyl substituted imidazole to thereby provide for acid gas (e.g., CO.sub.2) absorption.
    Type: Grant
    Filed: October 31, 1985
    Date of Patent: October 4, 1988
    Assignee: Texaco Inc.
    Inventor: Edward C. Yit Nieh
  • Patent number: 4775520
    Abstract: Highly monodispersed nonporous spherical SiO.sub.2 particles are prepared having mean particle diameters between 0.05 and 10 .mu.m with a standard deviation of not more than 5% and a method for the preparation of such particles. The particles can be produced by a two step process wherein first a sol of primary particles is prepared by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous/alcoholic ammoniacal medium. The SiO.sub.2 particles are then converted to the desired particle size by a continuous measured addition of tetraalkoxysilane or organotrialkoxysilane controlled by the extent of the reaction. The SiO.sub.2 particles produced by this process are particularly useful as sorption material in chromatography.
    Type: Grant
    Filed: September 25, 1986
    Date of Patent: October 4, 1988
    Assignee: Merck Patent Gesellschaft mit Beschrankter Haftung
    Inventors: Klaus Unger, Herbert Giesche, Joachim Kinkel
  • Patent number: 4770864
    Abstract: An SO.sub.2 -containing gas, in particular, pre-stage gas for the Claus reaction to recover sulfur can effectively be purified by removing NH.sub.3 contained therein using a TiO.sub.2 catalyst.
    Type: Grant
    Filed: June 9, 1987
    Date of Patent: September 13, 1988
    Assignees: Mitsui Miike Eng. Corp., Rhone-Poulenc Specialties Chimiques
    Inventors: Takayuki Fujimoto, Osamu Matsunaga, Susumu Chawanya, Kouichi Shirai, Morito Okamura, Thierry Dupin
  • Patent number: 4769107
    Abstract: A process and apparatus for the manufacture of silicon blocks having a columnar structure comprising monocrystalline crystal zones having a crystallographic preferred orientation. In a casting process, each mold filled with molten silicon is transferred, before the silicon has solidified completely, to a separate crystallization station where the silicon can then crystallize completely. During this process, the exposed surface of the silicon is maintained in a molten state until the end of the solidification process has almost been reached. The process allows the various, necessary steps to be carried out simultaneously and yields high-quality solar cell base material.
    Type: Grant
    Filed: June 26, 1985
    Date of Patent: September 6, 1988
    Assignee: Heliotronic Forschungs- und Entwicklungsgesellschaft fur Solarzellen-Grundstoffe mbH
    Inventors: Dieter Helmreich, Cord Gessert, Hans-Dieter Miller, Helmut Zauhar, Georg Priewasser, Leonhard Schmidhammer
  • Patent number: 4765873
    Abstract: A process for removing hydrogen sulfide from a gaseous stream containing hydrogen sulfide by contacting said stream with an aqueous solution of ammonium hydroxide to produce ammonium sulfide; converting said ammonium sulfide to an ammonium polysulfide intermediate in an electrolytic cell at ambient temperature and pressure; and oxidizing said ammonium polysulfide to sulfur in a heating zone utilizing an oxygen containing gas sparge.
    Type: Grant
    Filed: December 6, 1985
    Date of Patent: August 23, 1988
    Assignee: The Dow Chemical Company
    Inventors: Dane Chang, Michael C. McGaugh
  • Patent number: 4758417
    Abstract: The invention provides a process for the removal of hydrogen sulphide from contaminated gas which comprises contacting contaminated gas with an aqueous ferric-ion solution in a first reactor, removing precipitated sulphur from the resulting aqueous iron-containing solution, oxidizing the aqueous iron-containing solution in a second reactor in the presence of an iron-oxidizing microorganism and separating resulting aqueous ferric-ion solution from the microorganism, characterized in that the pH of the aqueous iron-containing solution in the second reactor is maintained in the range 1.2 to 1.9, the total iron concentration in the aqueous solution is at least 15 kg/m.sup.3, and the aqueous ferric-ion solution is separated from the microorganism by ultrafiltration.
    Type: Grant
    Filed: October 23, 1986
    Date of Patent: July 19, 1988
    Assignee: Shell Oil Company
    Inventors: Constant J. van Lookeren-Campagne, Stephen P. Moore, Edward D. A. Obeng
  • Patent number: 4756896
    Abstract: The invention relates to a method for preparing polycrystalline pure silicon by reducing gaseous silicon tetrafluoride at a raised temperature by means of alkali metal or alkali earth and by recovering the silicon by means of liquid phase separation. According to the invention, the gaseous silicon tetrafluoride is reduced by fused alkali metal or alkali earth or powder dispersed into a liquid intermediate agent boiling at a high temperature.
    Type: Grant
    Filed: April 27, 1987
    Date of Patent: July 12, 1988
    Assignee: Kemira Oy
    Inventor: Aarno Hayha
  • Patent number: 4756895
    Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.
    Type: Grant
    Filed: August 22, 1986
    Date of Patent: July 12, 1988
    Assignee: Stemcor Corporation
    Inventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
  • Patent number: 4755368
    Abstract: A process for formation of a silica filler product comprising the steps of subjecting fluidized silicon powder to combustion at a temperature of about 3000.degree. K. and quenching the combustion products to form a silica powder characterized by a large proportion of discrete, non-agglomerated primary particles.
    Type: Grant
    Filed: June 26, 1986
    Date of Patent: July 5, 1988
    Assignee: Ulrich Research & Consulting, Inc.
    Inventors: Gael D. Ulrich, Dennis W. Molesky
  • Patent number: 4753783
    Abstract: Process and apparatus for producing low cost, high purity solar grade silicon ingots in single crystal or quasi single crystal ingot form in a substantially continuous operation in a two stage reactor starting with sodium fluosilicate and a metal more electropositive than silicon (preferably sodium) in separate compartments having easy vapor transport therebetween and thermally decomposing the sodium fluosilicate to cause formation of substantially pure silicon and a metal fluoride which may be continuously separated in the melt and silicon may be directly and continuously cast from the melt.
    Type: Grant
    Filed: November 26, 1985
    Date of Patent: June 28, 1988
    Assignee: SRI International
    Inventor: Angel Sanjurjo
  • Patent number: 4752458
    Abstract: A method of preparing spherical microparticles of silica comprising adding an acid solution to a silicate solution before or after addition of an alkali metal alginate, ammonium alginate, starch, gelatin, pectin or mixtures thereof. The microparticles can be used to prepare macroporous materials having a controlled pore structure.
    Type: Grant
    Filed: February 11, 1987
    Date of Patent: June 21, 1988
    Inventor: Eric Robinson