Abstract: For removing hydrogen phosphide from waste air, the hydrogen phosphide-containing waste air is passed at temperatures from 50.degree. to 350.degree. C. over a catalyst which is composed, at least on its surface, of at least one metal which, in a 1-molar acidic aqueous solution, has a potential which is at least 200 mV more positive than that of the standard hydrogen electrode.

Abstract: A process for the treatment of ground, spent potlinings generated during the production of metallic aluminum to reduce cyanide content to environmentally nonhazardous levels. Potlinings are ground or otherwise suitably reduced in size to a particle size of not greater than about 2 inches in any dimension and roasted in a stream of air or nitrogen at a temperature between about 500.degree. F. and 1400.degree. F. Roasting for an appropriate time-temperature interval reduces cyanide content to desired levels without combustion of a major portion of carbonaceous material, resulting in an end product rich in carbon and fluorine which may be salable because of this content.

Abstract: A method of tailoring the heat balance of the outer edge of the dendrites adjacent the meniscus to produce thinner, smoother dendrites, which have substantially less dislocation sources contiguous with the dendrites, by changing the view factor to reduce radiation cooling or by irradiating the dendrites with light from a quartz lamp or a laser to raise the temperature of the dendrites.

Abstract: Sodium sulfate-containing residues are worked up by reducing the sulfate by a process in which the sulfate or a mixture or solution of the sulfate is thermally cleaved by adding oxygen, air or oxygen-enriched air at above 1000.degree. C., in particular above 1200.degree. C., under reducing conditions to give gaseous sulfides and oxides of sulfur as well as alkaline slag. The sulfur compounds contained in the gaseous reaction products can be further processed to sulfur, sulfur dioxide and sulfuric acid.

Abstract: A method and apparatus for crystal growth control in a Czochralski crystal pulling process are provided wherein a plurality of thermocouples and individually controllable heating elements are embedded in an upper control section of a raised platform in a crucible containing a melt from which the crystal is pulled. The upper control section is disposed in the melt at a height below the bulk level of the melt in the crucible and underneath the crystal being pulled so as to retain the thermocouples in a position to monitor the temperature distribution of the melt below a solidification front of the crystal, and to retain the individually controllable heating elements in a position whereby the heating elements may be selectively controlled to attain a predetermined temperature distribution in the melt in a region underneath the solidification front.

Abstract: A process for controlling the concentration of aluminum in the brine of a membrane chlor-alkali cell is disclosed wherein the brine has its calcium carbonate settler solids digested in the calcium chloride flow stream by the addition of an inorganic mineral acid to bring the pH to about 2.0 to about 3.0 to solubilize the aluminum in the brine. The brine has the pH adjusted upwardly to reprecipitate the aluminum onto carrier particles and then removes the reprecipitated aluminum and carrier particles from the brine by filtration or centrifugation.

Abstract: The major portion of the crucible in which a compound semiconductor ingot is grown has an inner surface which, in a section taken transverse to the crucible axis, substantially defines an ellipse. As a consequence, the ingot grown in the crucible has an elliptical cross-section. After the ingot is removed from the crucible, it is cut at an angle with respect to the central axis of the ingot and in the direction of the minor axis of the ellipse defining the ingot cross-section. Wafers cut from the ingot will have a circular periphery if the sine of the angle at which they are cut substantially equals y.div.x where y is the thickness of the ingot along the minor axis of the ellipse, and x is the thickness of the ingot along the major axis of the ellipse.

Abstract: A process is disclosed for producing high purity mercuric iodide by passing a gaseous source of a mercuric compound through a particulate bed of a low vapor pressure iodide compound which is maintained at an elevated temperature which is the lower of either: (a) just below the melting or volatilization temperature of the iodide compound (which ever is lower); or (b) just below the volatilization point of the other reaction product formed during the reaction; to cause the mercuric compound to react with the iodide compound to form mercuric iodide which then passes as a vapor out of the bed into a cooler condensation region.

Abstract: Stable, encapsulated superparamagnetic magnetite particles having a narrow particle size distribution with average particle diameters in the range of from about 50 .ANG. to about 350 .ANG. are prepared by forming an aqueous dispersion of magnetite particles having the above particle size characteristics in the presence of a surfactant, coacervating a mixture of gelatin and a carboxyl containing hydrophilic polymer such as gum arabic to form a thin coating of coacervate on the magnetite particles and crosslinking the coacervate coating with a gelatin hardener such as glutaraldehyde.

Abstract: A heat pipe coracle is provide for use in a crystal growth apparatus; the heat pipe coracle includes a coracle ring, the coracle ring being composed of a material resistant to attack from a melt of the crystal growth apparatus and having density less than the melt so as to float upon the melt, the coracle ring having a central opening therethrough, the central opening being of a diameter approximately equal to that of a single crystal pulled from the melt through said central opening, the single crystal being in sliding contact with the coracle ring to insure uniform heat distribution about a vertical axis near an interface between the single crystal and the melt, and means for centering the coracle ring within a crucible of the crystal growth apparatus, the means for centering fixedly attached to the coracle ring and resistant to attack from said melt, the means for centering being in sliding contact with the wall of the crucible so that the heat pipe coracle can float upon said melt and below an encapsulati

Abstract: A magnetic fluid containing fine particles of ferrite stably dispersed in a low vapor pressure base oil is prepared by adding N-polyalkylenepolyamine-substituted alkenylsuccinimide (and a low vapor pressure base oil) to a suspension of fine particles of surfactant-adsorbed ferrite dispersed in a low boiling point hydrocarbon solvent, heating the resulting mixture, separating the hydrocarbon solvent therefrom, adding a low vapor pressure base oil and a specific dispersing agent to the fine particles of N-polyalkylenepolyamine-substituted alkenylsuccinimide-coated ferrite as the residues and subjecting the resulting mixture to a dispersion treatment.

Abstract: A method for neutralization of sulfuric acid containing Fe ions, comprising adding ions selected from the group consisting of Na ions, K ions, Mg ions, Ca ions and NH.sub.4 ions in the form of a compound containing chlorine to a sulfuric acid solution to be treated in an amount corresponding at least to the chemical equivalent to SO.sub.4.sup.2-, and bringing the resultant solution into contact with an organic solvent containing oxygen or comprising alkylamine for extracting Fe ions from said aqueous solution into the organic phase as chloride complex. Iron chloride can be recovered from the organic phase by distilling or evaporating the organic solvent or by extracting back it into water.

Abstract: A method of preparing a kneaded mixture for a magnetic coating material comprises a kneading start process and a continuous kneading process. In the kneading start process, a low-viscosity composition, which is composed of magnetic layer forming materials containing ferromagnetic grains and a binder, and a solvent, is introduced into a kneading vessel of a two-shaft continuous kneading and mixing machine, and kneading is started. In the continuous kneading process, after the start of the kneading, a high-viscosity composition, in which a solvent amount is smaller by at least 7 wt % than the solvent amount in the low-viscosity composition used in the kneading start process, is continously introduced into the kneading vessel, and the kneading is continued while high shearing force is being given to the high-viscosity composition.

Abstract: Superparamagnetic liquids comprising:(A) magnetic particles in stable colloidal suspension; (B) an A-X-B dispersant wherein A is derived from a non-ionic surface active agent, B is a carboxylic acid group and X is a connecting group between A and B; and (C) a carrier liquid which is a thermodynamically good solvent for A but which does not form a stable superparamagnetic liquid with magnetic particles coated only with oleic acid.

Abstract: For the production of a gaseous mixture contains chlorine dioxide and chlorine, alkali chlorate in an aqueous solution with acid is reacted in a reactor. The reactor comprises a plurality of superimposed reaction levels which are traversed by the solution from top to bottom. In the lower portion of the reactor the solution in which chlorate and acid have been depleted is reboiled in a reboiling chamber by an indirect heating at a temperature in the range from 100.degree. to 110.degree. C. The depleted solution is conducted from the reboiling chamber to a pressure chamber, in which a pressure of at least 1.2 bar is maintained. In the pressure chamber the solution is reboiled at temperatures from 110.degree. to 150.degree. C. and the vapors formed by the reboiling in the pressure chamber are conducted through the reboiling chamber for an indirect heating therein.

Abstract: A process for manufacturing high purity anhydrous hydrogen fluoride (HF) having low levels of arsenic impurity by contacting anhydrous hydrogen fluoride product, or an intermediate product obtained during the manufacture of HF, with hydrogen peroxide to oxidize the arsenic impurity in the presence of a catalyst which comprises a catalytic amount of a component selected from the group consisting of molybdenum, a molybdenum compound, vanadium, and a vanadium compound, and a phosphate compound. The volatile trivalent arsenic impurity in the anhydrous hydrogen fluoride is oxidized to a non-volatile pentavalent arsenic compound and the resultant mixture is distilled to recover high purity anhydrous hydrogen fluoride with reduced levels of arsenic impurity. In one embodiment, an oxidizing agent such as nitric acid or a nitrate salt is added to the reaction mixture to oxidize organic compounds.

Abstract: There is disclosed the use of a quaternary ammonium salt of an alkoxysilane as a dispersant for magnetic pigment particles in the preparation of magnetic recording media. The dispersant of the present invention can bind to the pigment particles and may be substituted for conventional phosphate ester dispersants which are incapable of binding to the pigment and tend to migrate to the surface of such media, thereby adversely affecting recording media performance.

Abstract: Chloric acid is produced in an electrolytic-electrodialytic process in which chlorate ions from a sodium chlorate solution are transferred through an anion-exchange membrane to combine with electrolytically-produced hydrogen ions in a compartment of a cell, from which the resulting chloric acid is recovered. The sodium ions are transferred through a cation-exchange membrane to combine with electrolytically-produced hydroxyl ions in another compartment of the cell, from which the resulting sodium hydroxide is recovered.

Abstract: Disclosed is a process for removing selenium from wastewater effluent. The processd includes the steps of;(i) contacting a selenide containing wastewater and a strong-base anion exchange resin to absorb selenide on the resin;(ii) eluting the ion exchange resin with an eluant which is effective for stripping selenide therefrom; and(iii) recovering elemental selenium from the selenide containing eluate resulting from step (ii). Also disclosed is a process for regenerating the ion exchange resin by treatment of the resin with an acidic chlorate solution.

Abstract: An emulsion acrylate copolymer is provided which unexpectedly is an effective magnetic binder inasmuch as it can be loaded with high amounts of one or more magnetic particles such as ferrite or ferrite containing materials to provide a flexible permanent type magnetic composition of high magnetic energy. The copolymer is made from an alkyl acrylate and a salt of 2-acrylamido-2-methylpropane sulfonic acid (AMPS). A carboxylated ethoxy alkyl phenol surfactant is utilized which provides good processability and permits a blend of the magnetic particles with the emulsion acrylate copolymer to be precipitated from a latex solution by high shear mixing. Flexible high magnetic energy magnets can thus be made and utilized in various applications such as refrigerator doors, electrical motors, and the like.