Abstract: This invention relates to a method for recovering aluminum hydroxide from alunite ore by roasting the ore to remove water of hydration, roasting it again in a reducing atmosphere to remove sulfate, roasting a third time in an oxidizing atmosphere to convert any sulfides formed in the second roast, leaching with a weak base, leaching with water to remove potassium and sulfate, extracting the aluminum content with a mixture of sodium hydroxide and potassium hydroxide, removing contaminant silica from the leach solution, and precipitating aluminum hydroxide by cooling and seeding the solution.

Abstract: The method comprises the steps of crushing of the ore, neutralization by a mixture of water and sulphuric acid, introduction of a controlled quantity of sulphur dioxide gas at a pH value between 1.5 and 4 for promoting dissolution of nickel, copper and a desired quantity of manganese, leaching of the ore with sulphuric acid at a pH value between 1 and 3 for selectively dissolving the nickel and copper, separation of the solid and liquid phases, and separation of the metals contained in the liquid phase.

Abstract: Aluminum trichloride is separated and recovered from its complexes with hydrocarbons and hydrogen chloride by contacting the complexes with metallic aluminum at 20.degree.-100.degree. C and recovering the resulting precipitate of aluminum trichloride.

Abstract: The filterability of aluminum salts precipitated from an aqueous solution containing dissolved aluminum ion is improved by adjusting the pH of the solution to between about 4 and 6, adding less than a stoichiometric amount of a 1, 3-dicarbonyl compound such as acetylacetone to the solution to precipitate the aluminum dicarbonyl and then adding a sufficient amount of an alkaline hydroxide to precipitate the remaining dissolved aluminum ion in the form of aluminum hydroxide to obtain a mixed precipitate which can be readily filtered.

Abstract: An improved process is provided for the recovery of sodium aluminate crystallized from a digest of caustic and lime with high-silica aluminous materials. The digest solution is concentrated by evaporation and then seeded with Na.sub.2 Al.sub.2 O.sub.4.2.5H.sub.2 O crystals to crystallize alumina from the solution as Na.sub.2 Al.sub.2 O.sub.4.2.5H.sub.2 O. The crystals are then separated from the mother liquor solution by filtration or centrifugation. The crystals are then washed with a solution having a lower caustic content than the mother liquor and an alumina concentration of about 50 grams per liter to remove any mother liquor remaining on the crystals. The sodium aluminate crystals are used as a feed for a subsequent Bayer processing step.

Abstract: In an epitaxial growth method in liquid phase for III-V compound semiconductor crystals a solution for crystal growth is at first heated to a temperature which is higher than the temperature of crystal growth, and then cooled to that temperature, whereby a part of the solution crystallizes out as small crystals. This solution is separated by means of a filter means into two parts, one of which contains the small crystals and the other of which does not. A substrate crystal is brought into contact with the latter.

Abstract: The present invention provides a method for recovering niobium from a hydrochloric acid solution which contains niobium and vanadium and which may also contain other metals such as, for example, zirconium, titanium, iron, chromium and aluminum. Broadly, the method comprises heating such a solution at a low pH for a period of time sufficient to form a niobium-containing precipitate substantially free of vanadium. Preferably, the solution is heated in the presence of a small amount of sulfuric acid. The precipitate then is recovered from the solution.

Abstract: The invention provides novel water-soluble copolymers useful as flocculating agents, especially in flocculating the red mud formed during the Bayer process for the production of alumina from bauxite. The copolymers comprise anionic monomer units e.g. acrylic acid units in a mole percentage of less than 50% and acrylamide type units some of which are methylolated.

Abstract: An improved wet caustic process of the Bayer method for the extraction of alumina from bauxite containing amounts of both goethite and a monohydrated alumina wherein lime is added only after the bauxite slurry has been heated to a digestion temperature of at least 200.degree.C.

Abstract: Uranium values are obtained from phosphate rock by acidifying phosphate rock containing uranium values and at least one other heavy metal with a mineral acid so as to obtain a crude acid, solvent extracting the crude acid with an organic solvent so as to separate a raffinate from a relatively pure, wet process phosphoric acid and treating said raffinate with a base so as to raise the pH to 1-2 whereby uranium hydroxide or phosphate and other heavy metal hydroxides or phosphates are coprecipitated. The uranium content of the coprecipitate after drying is at least as high as 0.3% which is comparable to that of uranium ores of the highest quality.