Abstract: Very small and uniform metal oxide particles are produced by a process including the steps of ejecting a metal vapor-containing gas into a metal-oxidizing region through a nozzle and ejecting a molecular oxygen-containing gas into the metal-oxidizing region through another nozzle in such a manner that the streams of the metal vapor-containing gas and the molecular oxygen-containing gas are smashed into each other to produce a turbulent flow diffusing flame in which the metal vapor is oxidized into very small and uniform metal oxide particles.

Abstract: Monovalent ions, especially chloride and fluoride, but also thallium, sodium and potassium are efficiently removed from ZnSO.sub.4 electrolyte by electrodialysis. Monovalent anions are removed using alternating monovalent anion permselective membranes and cation exchange membranes. Monovalent anions and cations are removed using alternating monovalent anion and monovalent cation permselective membranes. Electrodialysis is carried out under turbulent conditions, at up to 60.degree. C., a differential membrane pressure of less than 150 kPa, a current density of 10 to 500 A/m.sup.2, and a pH of less than 5.5. Where both chloride and fluoride are removed a pH of 3.5 to 5.5 is maintained.

Abstract: A process for distillation-crystallization of a zinc carbonate which is characterized in that a distillation column having a plurality of plates or trays is used for crystallizing basic zinc carbonate (2ZnCO.sub.3.3Zn(OH).sub.2 or ZnCO.sub.3.3Zn(OH).sub.2 H.sub.2 O) from a solution of basic zinc ammonium carbonate (Zn(NH.sub.3).sub.4 CO.sub.3); said solution is fed to an upper portion of the distillation column, while heating a bottom portion of the distillation column, to effect a distillation operation.

Abstract: A process for selectively stripping and separating iron ions from an organic solvent (A) which comprises bringing the organic solvent (A) containing iron and zinc ions, and containing one or more compounds selected from the group consisting of alkyl phosphoric acid, alkyl-aryl phosphoric acid, alkyl thio phosphoric acid and alkyl-aryl thio phosphoric acid together with a petroleum hydrocarbon as a diluent, into contact with an aqueous solution containing NH.sub.4.sup.+ and F.sup.- ions so as to selectively strip the iron ions into the aqueous solution despite the coexistence of zinc ions.

Abstract: A method for making ultra-fine ceramic particles, in which metal powder constituting a portion of the ultra-fine ceramic particles intended for production is injected at a rate of not less than 70 grams per minute into a plasma jet so that the metal powder is vaporized. The vaporized metal powder is then mixed with a reactive gas, which includes an element consituting the other portion of the ultra-fine ceramic particles, filled in the surrounding area of the plasma jet, and thereby the vaporized metal powder and the reactive gas produce a synthetic reaction. The ultra-fine ceramic particles are produced continuously because of the reaction flame.

Abstract: A method for recovering zinc from substances containing a zinc compound which comprises supplying a carbonaceous substance and a zinc compound-containing substance onto the hearth layer in a sintering apparatus, vaporizing the zinc compound in said substance as metal to separate the compound therefrom by forming a locally strong reducing atmosphere at the combustion temperature of sintering material, oxidizing the resultant vapor-form zinc into zinc oxide under a strong oxidizing atmosphere, and then discharging the resultant zinc oxide as such from said sintering apparatus.

Abstract: This invention provides a process for production of a microcrystalline metal oxide having an average particle size less than about 1000 angstroms.An important feature of the invention process involves the application of ultrasonic wave energy during the stage that a solution of metalorganic compounds is being treated to form a gelled solution. The ultrasonic energy input during the gelling stage enhances the production of a high purity metal oxide powder having fine grain particles of uniform microspheric dimensions.

Abstract: Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

Abstract: This invention relates to a novel composite pigment and method for its manufacture which comprises a finely-divided inert pigment as a core which has deposited on its surface a non-photoconductive grade of zinc oxide, the weight ratio of zinc oxide ranging from about 30% to about 80% of the total weight of the composite pigment and the composite pigment characterized by a specific surface in excess of about 10 square meters/gram. In rubber compounding, the composite pigment reduces the cost of the zinc essential to produce quality products and the composite pigment because it is itself photoconductive is of utility in photoconductive end uses.

Abstract: H.sub.2 S is removed from a stream of gas such as coal gas at a relatively elevated temperature (300.degree.-400.degree. F.) in a process which employs sulfates or hydroxides of nickel, iron, or zinc as sulfur absorbents. The absorbents are converted to metal sulfides during the absorption process and are regenerated by aeration. Acids produced during sulfur absorption and absorbent regeneration steps are neutralized through the addition of a base. In a preferred embodiment ammonia is also removed and elemental sulfur is produced during the process.

Abstract: A process for the gasification of solid carbon comprising heating under suitable conditions a feed comprising finely divided particles formed by admixing finely divided particles of solid carbon with a slurry of zinc nitrate, removing enough of the liquid of said slurry to give a solid product, calcining said solid product at a temperature no greater than about 550.degree. C. to convert a substantial portion of the zinc material to zinc oxide, and then comminuting the calcined material to the desired particle size.

Abstract: There is disclosed an improved process and apparatus for the production of finely-divided metal and metalloid oxides by flame hydrolysis of corresponding metal and metalloid halides whereby fouling of burner apparatus is substantially completely avoided.

Abstract: A method for removing carbonaceous impurity from zinc oxide by contacting a water slurry of contaminated zinc oxide with oxygen in a reactor at reaction conditions sufficient to produce oxide products of the carbon contaminants and passing the reactor effluent through a filter to collect solid zinc oxide while passing the oxides of carbon through the filter. In a preferred embodiment, contaminated zinc oxide separated from the reaction product in the preparation of terephthalic acid from benzoic acid using zinc benzoate catalyst is subjected to treatment for removal of carbonaceous contaminants before being recycled to reaction with molten benzoic acid to produce zinc benzoate catalyst used in the reaction.

Abstract: Basic zinc compound flake-like crystalline material suited for use in crystal-oriented electronic devices and method for preparation thereof comprising the steps of preparing a solution including at least zinc ions and sulfate ions, and causing precipitation of zinc sulfate crystals by causing a reaction of components of said solution with alkali when said solution is at a temperature in the range 50.degree. to 100.degree. C. and has a pH value of in the range 4 to 6.5.

Abstract: This invention relates to stable, fluid zinc-containing dispersions and the preparations thereof by the high temperature decomposition of ZnCO.sub.3 to ZnO in a dispersant-containing fluid.

Abstract: Zinc oxide is interacted with an aqueous solution containing a chromium chromate complex obtained through partial reduction of an aqueous solution of chromic acid with an organic reducing agent. The resulting product is dried and the residual solid ground to suitable size for use as a pigment.

Abstract: A process for the production of electrophotographic grade zinc oxide which comprises heating zinc oxide to a temperature of between 150.degree. C. and 800.degree. C. and then treating the heat treated zinc oxide with an organic compound having at least two carbon atoms and containing an alkene group.

Abstract: A carbon source and zinc oxide are reacted in a reactor to form a gas consisting essentially of carbon monoxide and zinc; the zinc is separated from the gas and reoxidized in indirect heat exchange relationship with the reaction mixture of the carbon source and the zinc oxide. A portion of the carbon monoxide and zinc-comprising gas formed can be recycled to the reactor as a fluidizing gas.

Abstract: A desulfurization process is provided using particulate zinc oxide shapes of high surface area and improved crushing strength prepared without extraneous binder by a process including forming normal surface area zinc oxide into shapes without binder, converting at least a portion of the zinc oxide to basic zinc carbonate by exposing the shapes in the presence of moisture, to a carbon dioxide-containing atmosphere and effecting substantially complete decomposition of the basic zinc carbonate. Conditions of bulk density, moisture content and temperature are controlled.

Abstract: A carbon monoxide- and zinc-containing gas is produced by the endothermic reaction of a carbonaceous material with zinc oxide. Zinc separated from the gas is in part reoxidized with air and in part reoxidized with H.sub.2 O to form zinc oxide both in exothermic reactions. Heat developed in these exothermic reoxidations is transferred to the endothermic CO-forming reaction so that the total system is thermally neutral, in other words neither generates nor consumes heat.

Abstract: A carbon source and zinc oxide are reacted in a reactor to form a gas consisting essentially of carbon monoxide and zinc. The zinc is separated and reoxidized in a zinc oxidizer. In the reactor and the zinc oxidizer, heat exchange means are provided for that are connected to each other to form a heat exchange loop through which a heat exchange fluid is circulated such as to supply heat generated in the zinc oxidizer to the reactor.

Abstract: Particulate zinc oxide shaped of high surface area and improved crushing strength are prepared without extraneous binder by a process including forming normal surface area zinc oxide into shapes without binder, converting at least a portion of the zinc oxide to basic zinc carbonate by exposing the shapes in the presence of moisture, to a carbon dioxide-containing atmosphere and effecting substantially complete decomposition of the basic zinc carbonate. Conditions of bulk density, moisture content and temperature are controlled.

Abstract: A method for recovering a substantially impurity-free zinc oxide product from steel-making flue dust or a similar material which comprises leaching the flue dust with concentrated ammonia and carbon dioxide to dissolve zinc and unwanted impurities, cementing the leach filtrate with zinc to remove copper, cadmium, and lead impurities, conducting a steam distillation on the cementation filtrate to precipitate basic zinc carbonate, remove the ammonia and carbon dioxide, and iron impurities, and filtering to provide a residue of essentially basic zinc carbonate, sulfur, and chromium. This residue is then washed to remove soluble sulfates, dried, and calcined at high temperatures to break down the basic zinc carbonate into zinc oxide, water washed to remove chromium and the residue of the water wash dried to produce the desired impurity-free zinc oxide product. The two water washes may be combined into one step performed after the calcining step to remove both sulfur and chromium in one wash step.

Abstract: A process for making overvoltage surge protection varistors of the zinc oxide type includes the steps of:A. sintering a varistor body at an elevated temperature of at least about 1100.degree. C; thenB. cooling the body to a temperature below about 400.degree. C; thenC. reheating the body to a temperature below about 700.degree. C; thenD. recooling the body slowly to a temperature below about 400.degree. C; and thenE. repeating at least once the steps (c) and (d)For improving the current stability of the varistor under alternating voltage stresses while preserving the level of current leakage through the varistor.

Abstract: A pressure sintering process for the fabrication of ultrafine grained cercs having improved strength and enhanced transparency comprising the cold compressing of a ceramic oxide powder having a cubic crystal structure, removing undesired gases, raising to a temperature at which full density of the compact can be obtained in isothermal increments of about 50.degree. under elevated pressures while maintaining the temperature at each incremental increase for a period of about 50-60 minutes, and recovering the product.

Abstract: A stable panchromatically sensitized zinc oxide having a low moisture sensitivity with dark discharge properties rendering it suitable as the photoconductive material of elements for indirect as well as direct electrophotography is produced by reacting finely divided zinc oxide with gaseous ammonia and carbon dioxide, while keeping the zinc oxide particles in motion, until a critical stage is reached corresponding usually to a weight increase of 4 to 7.5%, at which point the reacting is terminated and the product is heated to constant weight at a temperature between 190.degree. and 350.degree. C. Photoconductive elements made with the panchromatically sensitive zinc oxide not only are reusable indefinitely under varying atmospheric humidity conditions without loss of their sensitivity, but also exhibit a memory effect much lower than that of known photoconductive zinc oxides.

Abstract: A method of producing hydrogen and oxygen by splitting water in a thermocical cycle, according to which in a first method stage a gas mixture of from 1 to 50 parts by volume of steam and 2 parts by volume of sulfur dioxide is reacted at a temperature within the temperature range of from 200.degree. to 400.degree. C with an oxide of one of the metals manganese, iron, cobalt, nickel, zinc or cadmium for forming a metal sulfate and for freeing hydrogen gas. Thereupon the hydrogen gas is in a manner known per se separated from the residual gas mixture and in a second method stage after conversion of the metal oxide to a metal sulfate, the metal sulfate for purposes of decomposition or disintegration and for forming a metal oxide, sulfur dioxide gas and oxygen gas, is heated to a temperature within the temperature range of from 700.degree. to 1000.degree. C. Thereupon the oxygen gas is separated from the sulfur dioxide gas in a manner known per se.

Abstract: A dilute aqueous slurry of hydrated zinc oxide is subjected to heat and pressure to obtain solids having improved filtering characteristics. The process is especially useful in the treatment of neutralized waste liquor from the viscose rayon system to provide a more economical method for the recovery of zinc sulfate.

Abstract: A thermochemical reaction cycle for the generation of hydrogen from water comprising the following sequence of reactions wherein M represents a metal:CH.sub.4 + H.sub.2 O .fwdarw. CO + 3H.sub.2 (1)co + 2h.sub.2 .fwdarw. ch.sub.3 oh (2)ch.sub.3 oh + so.sub.2 + mo .fwdarw. mso.sub.4 + ch.sub.4 (3)mso.sub.4 .fwdarw. mo + so.sub.2 + 1/2o.sub.2 (4)the net reaction is the decomposition of water into hydrogen and oxygen.

Abstract: A process for the recovery of metal values, principally zinc and copper, from an aqueous acidic purge stream in a hydrometallurgical process by contacting the stream containing the iron, copper and zinc sulfates, along with trace amounts of other metallic sulfates with calcium oxide to bring the pH in the range 3.0-4.0, thence with sufficient ammonia to form the soluble tetrammine sulfates of copper and zinc, then separating the copper from the zinc, e.g. by hydroxy oxime-solvent extraction and thereafter recovering the zinc as zinc oxide by converting the zinc tetrammine sulfate to the hydroxide and removing ammonia from the complex.