Abstract: Thin film epitaxial layers of mixed oxide compounds, or of solid solutions of two mixed oxides, are deposited on a suitable single crystal substrate. Growth is achieved by introducing the substrate into a crucible containing a saturated solution of the oxide(s) in a molten alkali metal halide having additional undissolved oxide(s) present in the crucible. Evaporation of the alkali metal halide solvent produces and/or maintains the supersaturated condition, which is relieved by epitaxial deposition of the oxide(s) onto the substrate. When two mixed oxides are dissolved in the solvent, the composition of the film is determined and fixed by the temperature of growth. To produce a thin film of a constant composition, growth is conducted isothermally. To produce a thin film with a graded composition throughout its thickness, growth is conducted by slowly cooling the temperature of the solution.

Abstract: A process for the extraction of gallium from sodium aluminate liquors comprises extracting gallium from aluminate liquors by cementation with the aid of a liquid gallium-aluminum alloy. Aluminate liquors produced in the Bayer process, prior to cementation, are freed from various impurities. To this end, the recycle aluminate liquor is cooled to a temperature at which soda crystallizes and vanadium is retained in the liquor, whereupon the crystallized precipitate is separated, while the residual liquor is mixed with the mother aluminate liquor in the ratio of 0.1-1 to 1-0.1. The resultant liquor is cooled down to ambient temperature, and the vanadium precipitate is separated. The process is a major step towards a simpler technique of gallium extraction from aluminate liquors both high and low in gallium. Also, the process permits extracting, directly from aluminate liquors, gallium in a higher degree of purity than can be obtained in the prior art.

Abstract: An aqueous nitric acid solution derived from an adipic acid process containing copper and vanadium catalyst values and alkyl dicarboxylic acids is treated to remove the nitric acid and water therefrom so as to obtain a substantially dry, molten-type residue. This residue is mixed with a dialkyl ketone solvent which dissolves the dicarboxylic acids and leaves the catalyst metal values as solids.

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: 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.

Abstract: A continuous process for extraction of niobium, rare earths and thorium from niobium ore concentrates which includes digesting the ore with a hot solution containing 13 to 16 moles of sulphuric acid per liter, diluting the solution to a concentration of 10 to 13 moles of sulphuric acid per liter, separating the insolubles from the solution which includes alkaline earth sulphates and the sulphates of thorium and rare earths that are present, reducing titanium in solution to the trivalent state and diluting the solution to a concentration of 5 to 7 moles of sulphuric acid per liter, separating the precipitated niobium oxide and sulphates of thorium and rare earths, and then concentrating the resulting solution to the level desired for recycle to the digestion stage.