Abstract: A process for increasing the amount of titanium dioxide in a titaniferous slag includes the rapid preheating of the slag in gases substantially void of free oxygen.

Abstract: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of sulfuric acid, ammonium sulfate, and ammonium persulfate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

Abstract: Manganese dioxide is produced from manganous salts by mixing a manganous salt with an alkali metal permanganate and/or ammonium permanganate followed by heating such mixture to about 150.degree. C. under an oxygen-containing atmosphere until at least 85% of the manganous salt is converted to manganese dioxide and then further elevating the temperature to about 250.degree. C. and maintaining this temperature until the surface area of the manganese dioxide is between about 3 square meters per gram and about 12 square meters per gram.

Abstract: Substantially homogeneous, substantially spherical interdiffused metallic oxide particles, especially useful in plasma spraying applications, are readily and economically prepared from constituent metal oxide powders by the method of this invention which includes the step of heating a mass of discrete agglomerated particles under conditions of temperature and time sufficient to interdiffuse the constituent metallic oxides within the agglomerates, but insufficient to sinter the agglomerates together.

Abstract: A method for manufacturing dielectric metal titanate MTiO.sub.3 where M represents Ba and Sr is disclosed, which comprises the steps of preparing aqueous alkaline solution containing at least one metal salt selected from the group of barium and strontium and immersing metal titanium into the solution to form the metal titanate MTiO.sub.3 where M is at least one of barium and strontium.Further, there is disclosed a method for manufacturing dielectric metal titanate MTiO.sub.3 where M represents Ba and/or Sr which comprises the steps of preparing aqueous solution containing at least one metal salt selected from the group of barium and strontium, forming a metal titanium layer on a substrate, and immersing the substrate with the metal titanium layer into the solution to convert the metal titanium layer into the dielectric metal titanate MTiO.sub.3 where M is at least one of barium and strontium.

Abstract: A process for transforming alumina hydrate into an anhydrous product comprising at least 10 wt % alpha alumina. Alumina hydrate is dehydrated, heated and transferred to a reactor where it is fluidized with steam and maintained at a temperature of about 900.degree.-1350.degree. C. Steam fluidization enhances crystal growth and results in a product having uniform quality and superior grinding characteristics.

Abstract: A process is disclosed for recovering tungsten and rhenium from a tungsten and rhenium bearing solution. The process involves adding sufficient hydrochloric acid to the solution to form a first precipitate containing essentially all of the tungsten and a first mother liquor having an acid concentration of at least about 1.25 normal, and containing the major portion the rhenium, followed by separating the first precipitate from the first mother liquor. A source of sulfide ions is then added to the first mother liquor with agitation for a sufficient time and with the amount of sulfide ions being sufficient to form a second precipitate containing essentially all of the rhenium which was in the first mother liquor, and a second mother liquor, followed by separation of the second precipitate from the second mother liquor.

Abstract: A process for the purification of spent liquor from an alumina precipitation stage is disclosed wherein the spent liquor is first contacted with 50 volume % or less ethanol to form a sodium oxalate precipitate and the, after removal of the sodium oxalate precipitate is contacted with over 50 volume % of ethanol extraction fluid to separate the mixture into a first layer comprising the ethanol and at least a portion of the caustic from the spent liquor and a second layer which comprises the remainder of the spent liquor. The spent liquor may then be subjected to a further precipitation to recover further alumina. The spent liquor remaining may be further treated in subsequent extraction steps to concentrate and dispose of undesirable impurities remaining.

Abstract: Wet oxidation of organic contaminants in aqueous sodium aluminate solutions is enhanced when a heated and oxygenated solution is passed through a packed bed containing a metal packing member that is chemically inert to sodium aluminate solutions at elevated temperatures. Process temperature is about 180.degree.-300.degree. C. and oxygen partial pressure is at least about 345 kPa. The packed bed has a packing surface of at least 100 square meters per cubic meter bed volume and preferably at least 50% free space.

Abstract: A process is disclosed for removing chromium from cobalt. The process involves first contacting an acidic cobalt chloride solution with an oxidizing agent, followed by adjusting the pH to from about 3.2 to about 5.5 with a base at a sufficient temperature to form a first solid containing essentially all of the chromium and a portion of the cobalt and a first liquor containing the balance of the cobalt, and then separating the first solid from the first liquor. The first solid is then heated at a sufficient temperature to remove essentially all of the water and form a second solid which is contacted with sufficient water and ammonium hydroxide to form a slurry which is at a pH of greater than about 3.8.

Abstract: Bayer process liquors derived from the digestion of bauxites with a caustic solution are purified by removing at least a portion of the organic impurities present in the liquors. Removal of these impurities is accomplished by treating liquor containing dispersed therein solids generated by the Bayer process or added thereto, such as red mud particles, alumina trihydrate, oxalate salt, or filter aid with an organic polymeric, water-soluble cationic quaternary ammonium salt (POLYQUAT salt) which due to its cationic nature will adhere to the surface of the dispersed solids. The organic coating or layer adhered to the solids provides a receptive surface for the organic impurities, thus allowing formation of a solid-Polyquat-organic Adduct which is easily removed from the Bayer system.

Abstract: A process for the production of aluminum trihydroxide having a controlled median diameter of less than 4 microns, with a unimodal distribution and minimum deviation. The process comprises grinding aluminum trihydroxide until the aluminum trihydroxide has a specific BET surface area of at least 8 m.sup.2 /g, adding the ground aluminum trihydroxide to a sodium aluminate solution, and then decomposing the solution to precipitate aluminum trihydroxide having the required median diameter.

Abstract: Spherical, submicronic, monodispersed, and non-agglomerated particles of metal oxides by reacting with steam a gaseous stream containing an aerosol of liquid particles of a hydrolyzable metal compound. Into a duct, in which an inert gas stream containing vapors of a hydrolyzable metal compound flows, there is fed through a nozzle a cold inert gas stream, the temperatures and flows of the two gaseous streams being such as to establish in the duct a temperature lower than the condensation temperature of the metal compound; the mixed gaseous streams having a turbulent flow in the duct, with a Reynolds number equal to or higher than 1800. At the duct outlet, the aerosol of metal compound liquid particles, which has formed in the duct, is caused to react with steam, wherefore solid particles of hydrated metal oxide form, which are subsequently calcined to the oxide.

Abstract: A process for rhenium recovery by the use of an anion exchange resin comprises eluting rhenium from the rhenium-adsorbed anion exchange resin with a hydrochloric acid solution containing a metal chloride. Preferred metal chloride is that of copper, cadmium, or zinc.

Abstract: Finely divided alumina, recovered from the dust recovery systems of alumina hydrate calcination facilities, is employed as seed for the precipitation of alumina hydrate from pregnant Bayer process liquors. The finely divided alumina dust can either be used as seed in as-is condition, or, if desired, agglomerated to coarse and strong particles prior to use as seed. Agglomeration is accomplished by combining the dust in a predetermined weight ratio with alumina trihydrate seed under controlled conditions. The process allows the utilization of an otherwise undesirable and unacceptable by-product of alumina hydrate calcination.

Abstract: A process for eluting indium from a chelate resin having a phosphorus atom-containing, chelate-forming group which contains adsorbed indium, which comprises contacting said resin firstly with a primary eluent containing an acid containing no halogen atom in the molecule at a concentration of 0.1N or higher and then with an eluent for indium which is selected from the group consisting of (1) a solution of an acid containing a halogen atom in the molecule, (2) a mixed solution of (a) a metal halide, an ammonium halide or a mixture thereof and (b) an acid and (3) a mixed solution of a sulfide and a base compound.

Abstract: A process for the production of alkali metal aluminum tetrahydrides from its elements by pressure hydrogenation, particularly characterized by production in the presence of an aluminate catalyst formed from NaAlCl.sub.4. The process is preferably carried out on a semi-continuous basis in which the active aluminum-containing heel is carried through to successive batches.

Abstract: A method of continuous ion exchange for waste water treatment and metal recovery employs two membranes, each disposed in its own fluid-tight chamber. A feed solution containing metal ions is passed in contact with one membrane, the opposite side of which is in contact with a recirculating flow of liquid ion exchange material which receives selected dissolved mineral ions. The liquid ion exchange material is then passed over a second membrane, the other side of which is supplied with an eluant solution for further selective recovery of the desired mineral ion or ions. During recirculation the liquid ion exchange material is preferably passed through an aqueous separator. An apparatus for the practice of the present invention is also disclosed.

Abstract: An improved method of preparing alumina, including a first stage in which an alumina hydrogel is formed from seed aluminum hydroxide, and a second stage in which the alumina hydrogel is processed for conversion into alumina.

Abstract: An improved process for the preparation of alumina, including forming an alumina hydrogel from aluminum hydroxide, and processing the alumina hydrogel into alumina. The improvement involves the alumina hydrogel forming step which is connected in the presence of sulfate ion and which comprises providing, in a reaction zone, an aqueous slurry containing seed aluminum hydroxide and having a pH of 6-11, and feeding to the reaction zone an aluminum compound and a pH controlling agent for mixing with the aqueous slurry while maintaining the aqueous slurry at a temperature of at least about 50.degree. C. at feed rates so that the pH of the aqueous slurry is maintained within the range of 6-11 and that 0.2-5 mols/hour of aluminum components, in terms of elemental aluminum, are fed to the reaction zone per mole of the seed aluminum hydroxide originally contained in the aqueous slurry, whereby the seed aluminum hydroxide is caused to grow to the aluminum hydrogel.