Abstract: A process is described for the formation of high purity alumina from Bayer Process alumina trihydrate (gibbsite). The solid hydrated alumina is reacted with concentrated HCl to cause partial or complete conversion to aluminum chloride hexahydrate (ACH). The ACH or mixture of ACH and unreacted hydrated alumina is recovered as a solid and calcined in a single or multistage calcination to high purity alumina. Soda contents in the product anhydrous alumina can be reduced by 98% or greater. Contents of other impurities, such as silica, iron, magnesium, etc., are also markedly reduced. Different degrees of impurity reduction can be obtained by controlling the degree of conversion of the hydrated alumina to ACH and by recycling and treating the acid after solid/liquid separation. The purified products find use in the specialty ceramics field, as catalyst supports, as adsorbents, in electronic components, in prosthetic devices or other applications in which alumina of controlled degrees of purity offers an advantage.

Abstract: A method for recovering gallium from an aqueous solution containing gallium, which comprises contacting the aqueous solution containing gallium to a porous polymer having a water-insoluble substituted quinolinol retained therein, to let the polymer adsorb gallium, and then eluting gallium from the polymer.

Abstract: The present invention relates to a simple process for the recovery of pure tungsten at a high yield from cemented tungsten carbide or tungsten alloys scrap. According to the invention the process consists of a series of steps characterized by certain critical parameters.

Abstract: A boehmite having a crystal form wherein the ratio of the maximum length in the direction of the a-axis to the distance between the opposing crystal faces perpendicular to the c-axis is at least 10.

Abstract: The present invention provides a process for recovering a tungsten compound from a waste liquor containing a high-boiling organic compound and the tungsten compound, which process comprises the steps of spray-burning said waste liquor at an air ratio of 1.05 or higher under conditions of a temperature and a residence time which lie within the region of a pentagon defined by points A, B, C, D, and E in FIG. 1; quenching the combustion product by immediately bringing it into direct contact with water; and recovering the tungsten compound.

Abstract: Sinterable metal-oxygen composition powders are prepared by mixing aqueous solutions of the metal salt and of poly(acrylic acid), or its ammonium salt, to form a precipitate which is dried, ignited to remove the organic composition and calcined to form the metal oxide or metal-oxygen compound powder.

Abstract: Silver or palladium metals are selectively extracted from aqueous sulfuric acid solution by contacting the solution with a water-immiscible organic solvent extraction solution comprising a tertiary phosphine sulfide compound; separating the resulting silver- or palladium- phosphine sulfide complex from the aqueous solution; and recovering the silver or palladium metal from the complex by suitable stripping means.

Abstract: The invention is characterized by two main methods of producing stabilized or partially stabilized zirconia powders with controlled particle size by use of complexing agents and hydrothermal treatment. A further embodiment of the invention is characterized by a combination of the first two methods to produce powders containing more than one major particle size. The invention also allows use of low cost readily available starting material, controlled doping level and incorporation of dual constituents such as MgO, CaO; Y.sub.2 O.sub.3, MgO; or Y.sub.2 O.sub.3, CaO in the structure for production of stabilized zirconia. Triply stabilized zirconia containing Y.sub.2 O.sub.3, MgO and CaO may also be produced. A final embodiment of the invention allows the production of dually and triply stabilized zirconia by hydrothermal treatment without the use of complexing agents.

Abstract: Process for the synthesis of vanadium V.sub.6 O.sub.13 by reduction of V.sub.2 O.sub.5 in the presence of reducing gas. The reducing gas is a mixture of CO and CO.sub.2.

Abstract: The process is directed to a fluidized bed chlorination of iron containing metaliferous materials to simultaneously produce a quantity of titanium beneficiate and a quantity of titanium tetrachloride. The process is controlled by maintaining the bed temperature between about 600.degree. C. and 1150.degree. C. while controlling the quantity of chlorine relative to the ratio of beneficiate to titanium tetrachloride desired.

Abstract: Disclosed is a process for beneficiating chromite ore. The process can also be used to remove SO.sub.2 from SO.sub.2 -air mixtures which would ordinarily be vented. The chromite ore is pulverized and preferably mixed with sodium sulfate. Ammonium carbonate can also be added for subsequent vaporization to increase porosity. Sulphur oxide-oxygen roasting of the chromite ore is conducted at elevated temperatures in the approximate range between 300.degree. and 1,000.degree. C. or higher at approximately atmospheric pressures. After roasting, the ore is preferably leached using an aqueous ferric sulfate solution to remove soluble undesired constituents from the roasted chromite ore. The beneficiated chromite ore shows improved chromium concentrations and chromium to iron ratios when compared to the original ore.

Abstract: This invention relates to the development of a viable metallurgical process capable of treating low grade concentrates, bulk concentrates, dirty concentrates, or ore directly for the recovery of non-ferrous metals such as zinc, lead, copper, and precious metals and accordingly is significant to the development of massive fine grained sulphide ore bodies found throughout the world. The process involves the consecutive steps of sulphatizing roasting in a fluidized bed reactor, a two stage leach, metal recovery from solution by conventional processes such as electrowinning and precipitation, and recycling of residue wash waters and leach liquors containing high concentrations of iron and minor impurity elements to the roaster or a spray dryer for thermal decomposition. Simple and efficient rejection of iron from the circuit to residue as stable hematite is the net result of the recirculation and thermal decomposition.

Abstract: A novel process for the recovery of alumina and potassium sulfate from alunite is provided comprising leaching the alunite with potassium hydroxide to which no sodium materials have been added, said leach solution being saturated with potassium sulfate. Aluminum values are solubilized into the leachate, and potassium and sulfur values are rendered soluble, but remain in the residue. The leachate is desilicated if necessary, preferably with lime, and aluminum trihydroxide is precipitated therefrom, followed by calcining to alumina product. The residue is leached to solubilize potassium sulfate in a secondary leach and the potassium sulfate product crystallized therefrom. Potassium hydroxide is regenerated from a portion of the potassium sulfate secondary leachate by several methods.Novel procedures for regenerating alkali metal hydroxides from the corresponding sulfates are also provided including routes involving formates and carbonates as intermediates and pyrohydrolysis.

Abstract: A process for the vapor phase production of alumina by introducing steam into the vapor space above a heated, liquid phase aluminum alkoxide in which the aluminum alkoxide is hydrolyzed in a heated reaction zone downstream from the liquid alkoxide and collected as a dry powder without the necessity for utilizing conventional drying processes.

Abstract: High purity alumina with a low sodium content and with a friable, easily ball milled structure is produced in this invention through a modified sol-gel procedure which includes digestion of the contaminant containing aluminum metal with hydrochloric acid in the presence of excess aluminum, removal of the contaminants, seeding the resulting sol with high purity alumina, drying to a solid, and then calcining said seeded sol solids to produce said high purity alpha alumina.

Abstract: A method of decomposing a super-saturated solution of alkali metal aluminate Ld from the Bayer process, by introducing primer Sa and forming a suspension with a high content of dry material, of at least 700 g/l of alkali metal aluminate solution to be decomposed, is characterized in that, for the purpose of obtaining Al(OH).sub.3 with a large, even particle size, a zone (Zs) for separating particularly fine solid particles of Al(OH).sub.3 is formed in decomposition zone (B) comprising a cascade of n stages of the Bayer process, the separating zone being fed with at least part L(n-3)1 of the flow of suspension Ln-3 circulating in said zone (B), from which a fraction LS.sub.1 is extracted, containing at least 5% of the total number of fine particles with a maximum diameter of 40 microns present in the flow Ln-3, while the residual suspension LS.sub.2 emerging from the separating zone Zs is recycled to zone (B), then the fraction Ls.sub.

Abstract: Disclosed is a process for producing purified alumina from high-silica bauxite including separating alumina-rich ore containing high-silica content into a coarse fraction and a fines fraction; digesting the fines fraction in a sodium aluminate solution at low temperatures; digesting the coarse fraction in a sodium aluminate solution at higher temperatures under pressure; and precipitating out alumina from the digest solutions after the combined liquors are desilicated during clarification.

Abstract: A high specific surface hydrargillite, well adopted as filler material or primer particulates in the production of finely divided aluminum trihydroxide by decomposition of Bayer process aluminate liquors, is readily prepared by (i) reacting an alkali metal aluminate with hydrofluoric acid at a temperature ranging from about 5.degree. to 95.degree. C., the amount of said hydrofluoric acid ranging from about 25% to 90% of that amount stoichiometrically required for complete neutralization of the alkalinity of said aluminate, (ii) optionally treating the hydrargillite precipitate which results at a temperature of from about 5.degree. to 95.degree. C. for from about one-half to 10 hours, and thence (iii) recovering said hydrargillite precipitate, preferably by filtering, washing and drying.

Abstract: A process is disclosed for removing potassium from a relatively impure molybdenum trioxide and forming a molybdenum compound of high purity. The process involves first contacting the impure molybdenum trioxide with an acid leach which consists essentially of a mineral acid and the ammonium salt of the mineral acid in a weight ratio of above about 3 to 1 of acid leach to molybdenum trioxide at a sufficient temperature and for a sufficient time to solubilize the major portion of the potassium and form a leached molybdenum trioxide, followed by separating the leached molybdenum trioxide from the resulting potassium containing acid leach. The leached molybdenum trioxide is then water washed to remove residual impurities and the washed molybdenum trioxide is dissolved in ammonium hydroxide having an ammonium concentration sufficient to form an ammonium molybdate solution from which is crystallized the highly pure molybdenum compound.

Abstract: A process for preparing metamorphosed alkaline metal titanates which comprises heating a mixture of at least one alkaline metal compound capable of being decomposed into an oxide of the alkaline metal and a gas by heating, and titanium dioxide, under a non-oxidative atmosphere, in the presence of at least one carbide represented by the formulaC(M).sub.z (1)wherein M is an element except carbon selected from groups III, IV and V in Periodic Table, and z is an integer corresponding to valency of M.The products have excellent heat resistance and electroconductivity and are useful as insulating materials.