Abstract: Monocrystals based on zirconium or hafnium dioxide stabilized with yttrium oxide having the following proportions of the said elements (in mol. %)Zirconium or hafnium dioxide: 70-90Yttrium oxide: 30-10.Said monocrystals may also contain oxides of the transition or the rare-earth elements or their mixtures in an amount of from 0.01 to 5% of the weight of the monocrystal.The method of producing the monocrystals consists in the preparation of a charge of zirconium or hafnium dioxide and yttrium oxide, melting of the charge, and growing the monocrystals from the obtained melt in the open air by the Stockbarger process.The obtained monocrystals obtained are transparent, colorless, have a high optical quality (a refractive index of n =2-2.2; a transmission band of 2,000-74,000 A), a microhardness of 1,300 to 1,500 kg/mn.sup.2, a dislocation density of 10.sup.3 to 10.sup.5 cm.sup.-2, and with various dimensions (a height of 1 to 8 cm, and a cross section of 0.5 to 4 cm.sup.2).

Abstract: A method for densifying a fumed metal oxide of Groups III and IV prepared by either a vapor phase oxidation or combustion process is disclosed wherein the metal oxide is mixed with a polar liquid in a high shear mixer, the metal oxide being present in an amount of about 35-50%, to convert it into a granulated material which, when dried, will substantially all pass through a 10 mesh screen. The granulated material may then be calcined preparatory to wet milling to prepare a casting slip, or it may be vitrified directly for molding or drawing in known manner.

Abstract: A method of increasing the bulk density of silica dust is disclosed. The silica dust is treated in a drum preferably having internal ribs whereby its bulk density is substantially increased.

Abstract: A method of compacting silica dust without the use of water is disclosed. The dust is charged to a hopper and is then injected with air under pressure whereby the weight per unit volume of the material is increased.

Abstract: It has been the practice to (a) withdraw hot, liquid UF.sub.6 from various systems, (b) direct the UF.sub.6 into storage cylinders, and (c) transport the filled cylinders to another area where the UF.sub.6 is permitted to solidify by natural cooling. However, some hazard attends the movement of cylinders containing liquid UF.sub.6, which is dense, toxic, and corrosive.As illustrated in terms of one of its applications, the invention is directed to withdrawing hot liquid UF.sub.6 from a system including (a) a compressor for increasing the pressure and temperature of a stream of gaseous UF.sub.6 to above its triple point and (b) a condenser for liquefying the compressed gas. A network containing block valves and at least first and second portable storage cylinders is connected between the outlet of the condenser and the suction inlet of the compressor. After an increment of liquid UF.sub.

Abstract: In a method of operating such chemical and physical reactions as oxidation, reduction, absorption, mixing, heat exchanging, deodorizing of a fluid or fluids, an improved method of performing a multi-effect operation of any one of a combination of such chemical and physical reactions with a substantial acceleration effect comprising the steps of passing a fluid mixture of exhaust gases and an absorbent solution under appropriate pressure and flow velocity conditions through a flow deflecting member provided within a reacting area, thereby causing the fluid mixture to flow in an accelerated whirling flow state and to be split into concentrically dual layers of a generally liquid fluid and a generally gaseous fluid under effect of centrifugal force produced from the whirling motion of the fluids, and thereafter directing the dual fluid flows to collide against a plurality of projection members having a special cross-sectional shape, thereby causing the fluid mixture flow to be agitated violently and developing d

Abstract: A process is described for recovering calcium hypochlorite values from the filter media employed in the filtration of calcium hypochlorite slurries. Deposits of Ca(OCl).sub.2 along with insoluble materials adhering to the filter media are washed with an aqueous solution of calcium hypochlorite to form a slurry of calcium hypochlorite solids. Water is used to wash the filter media to dissolve any remaining Ca(OCl).sub.2 and form a solution of calcium hypochlorite. The slurry and solution are then admixed to provide a solution of calcium hypochlorite whose concentration is controlled within the range of from about 45 to about 215 grams per liter of Ca(OCl).sub.2. This solution is employed in the production of calcium hypochlorite and is recycled to the washing step.

Abstract: In dual temperature systems utilizing different fluid materials in liquid and gas phases separable from each other (for example H.sub.2 O and H.sub.2 S), the phases are contacted with each other at a relatively hot temperature. Herein combinations of method and means are provided by which the gas is conditioned by raising its temperature and humidity principally by heat derived from the cooling and dehumidification of said gas. Special provisions are made in the combinations for transferring said heat and for the conditioning of the gas with high efficiency; and for economically controlling the temperature of the condensate resulting from the dehumidification of the gas to adapt it for particular uses in the system. Method and means are provided for such liquid gas contacting systems for efficiently stripping or separating dissolved gas from the effluent liquid and returning one of the so separated materials to the system.

Abstract: 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 silica. The furnace is provided with a resistance heating element which extends into the furnace interior through a top opening. In one embodiment a slidable filling tube is provided for charging the furnace during rotation thereof. The process utilizes the above-described apparatus and involves heating the crystalline silica to a temperature sufficient to convert it to the amorphous state, evacuating the furnace during the conversion to draw off by-product gases, and rotating the furnace to a speed sufficient to bring about a separation between the silica charge and the resistance heating element.

Abstract: In order to control the sodium oxalate level in the liquor employed in the Bayer process for the production of alumina, a part of the spent liquor recovered from alumina trihydrate precipitation stage is concentrated by evaporation to render it supersaturated with respect to sodium oxalate. The thus concentrated liquor is then sprayed onto a packing in an enclosed space under conditions such that the supersaturation of the droplets at impact on the packing exceeds a critical supersaturation. The sprayed liquor deposits sodium oxalate on the packing and is recovered for recirculation to the process circuit.

Abstract: An apparatus for extracting organic materials from a sample of a solid matrix containing such organic materials, the apparatus comprising an outer tubular member containing a permeable sample support positioned intermediate the first and second ends of the outer tubular member, and a method for the extraction of such organic materials by applying heat to one end of the outer tubular member while cooling the other end of the outer tubular member. Optionally a solvent is used in the extraction in conjunction with alternate heating and cooling of the ends of the outer tubular member.

Abstract: Abrasion resistant sodium perborate monohydrate is prepared by treating sodium perborate monohydrate with at least 5% of water at a temperature of 20.degree. - 90.degree. C. in a moistening unit and then drying at a temperature beginning at 40.degree. C. and increasing to a maximum of 90.degree. C.

Abstract: Newly precipitated MnO(OH).sub.2 is either added to an NH.sub.4 F solution that has been made slightly basic or this compound is formed in the NH.sub.4 F solution by adding an Mn (II) and an Mn (VII) salt solution. MnO(OH).sub.2 absorbs As and noble metal ions. The purity obtained is 10.sup..sup.-8 per cent by weight (starting from .ltoreq.10.sup..sup.-5 per cent by weight) of NH.sub.4 F solution.

Abstract: A water-soluble alkali metal compound or other soluble constituent is recovered from a mixture of solid particles of different densities and the solid particles are simultaneously separated into two fractions, one having a greater density than the other by countercurrently contacting the solids with a leaching agent in which said constituent is soluble in a countercurrent multistage leaching system, maintaining the density of the enriched leaching agent in the final stage of the system at a value intermediate the densities of the particles in the mixture, and separately recovering enriched leaching solution, particles having a density greater than that of the enriched leaching solution, and particles with a density less than that of the enriched solution from the system. The process is particularly useful for the recovery of alkali metal constituents used to catalyze the gasification of coal and other carbonaceous solids.

Abstract: A process is described for purifying liquids by cryogenic sublimation. This process involves solidifying the liquid by reducing the temperature and pressure to below the triple point. Purification is then carried out by direct transformation from the solid to the vapor phase. Because of increased differentials in vapor pressures at the low temperature at which the procedure is carried out, this purification process is highly efficient and is also particularly suitable for liquids that are susceptible to decomposition with ordinary purification procedures requiring elevated temperatures. The procedure is also advantageous in separating azeotropes, structurally similar compounds, as well as treating flammable, hydroscopic, corrosive and fuming compounds.

Abstract: A continuous process for removing nitrates from nitrate containing aqueous solutions having a pH of about 0-7, which comprises: (1) extracting the nitrate containing aqueous solution with an organic amine salt dissolved in an organic solvent phase whereby the nitrate ion goes into the organic solvent, (2) separating the organic phase, (3) stripping the organic extraction solvent phase from the extraction with a stripping salt solution of pH at least 0.

Abstract: A method for producing concentrated alumina slurries containing from about 14 to about 20 weight percent Al.sub.2 O.sub.3 by forming a solvent-aqueous alumina mixture and evaporating solent-aqueous vapor from said mixture to produce said concentrated alumina slurries.

Abstract: The present invention relates to a method and apparatus for purifying selenium or its alloys by precipitation. The method is characterized in that a smaller portion of a larger amount selenium or selenium alloy is kept at the respective transition temperature between solid and liquid phases while the remaining portion is maintained at a higher temperature for a time sufficiently long to allow a substantial concentration of foreign elements in the smaller portion.The apparatus is characterized in that it consists of a glass vessel having a height approximately 10 times its diameter, provided with temperature indicators governing devices controlling the heat supplied to electrical elements arranged around the vessel, it also being provided with a tightly-fitting hood and a gas evacuation device.

Abstract: Evaporation of water from a salt-saturated liquid is facilitated by adding a particulate solid having a density greater than that of the saturated liquid, and by maintaining a thin surface layer of liquid by settlement of the solids to leave an optimum one to two mils thickness of said layer.Agitation is employed to restore the optimum thin layer, as required to overcome excessive settling or too rapid evaporation of the thin layer, referred to respectively, as a heavy layer of liquid, or a dry surface skin.

Abstract: Minute amounts of boron present in naturally occurring brines found in oceans, inland seas, salt lakes and the like are removed by treating the brine with a solid, finely divided lignite.

Abstract: Method of hardening powdered titania (titanium dioxide) so as to make it attrition-resistant and to enhance its properties as a catalyst carrier. The method involves thoroughly dispersing powdered titanium dioxide in water, removing the excess water, drying and then calcining the product at a temperature between 650.degree.C and 900.degree.C. Preferably a large excess of water is used, at least 37% to effect dispersion; and dispersion may be aided by use of a surfactant, a water soluble organic compound or a highly polar inorganic compound. The excess water may be removed by filtration or the use of flocculants.The resultant powdered material is particularly useful as a carrier for oxidising ortho-xylene to phthalic anhydride.