Abstract: This invention relates to an improvement in the well known "Bayer" process. In particular, the invention describes a process for the recovery of gallium and alumina from bauxite including the steps of:A. dissolving the ore in caustic soda solution under pressure;B. precipitation of pure alumina from the remaining caustic soda solution by reduction of temperature and pressure;C. subjecting the resulting mother liquor from (b) to an elevated temperature of 60.degree. to 450.degree. C and a pressure of 2 to 100 atmos. in the presence of an oxygen-containing atmosphere; andD. cementation of the gallium remaining in solution by contact with metallic aluminium.Step (a) is preferably carried out at a pressure of 5 atmospheres and step (c) is carried out in the presence of an atmosphere consisting substantially of oxygen at a pressure within the range 20 to 50 atmospheres and a temperature within the range 150.degree. to 350.degree. C.

Abstract: This invention relates to the separation and purification of platinum group metals and, in particular to the separation of mixtures of rhodium, platinum and irridium. According to one specific form of the invention, the platinum, rhodium and iridium are present as salts in aqueous solution and the separation and purification is accomplished byA. adjusting the pH, as necessary, to provide an acidic solution;B. contacting the acidic solution with an oxidizing agent sufficient to effect the oxidation of all irridium to Ir(IV);c. contacting the oxidized solution with a nitrogen-containing organic compound selected from the group consisting of secondary amines, tertiary amines and quaternary ammonium compounds; andD. removing from contact with the oxidized solution an organic phase containing substantially all of the platinum and iridium present in association with the nitrogen-containing organic compound used in step (c).

Abstract: This invention relates to the recovery of gallium from scrubber dust containing aluminum and fluoride. In carrying out the process of the invention gallium is recovered from a particulate solid of the basic material by means of a process comprising the following steps:A. preparing a mixture of the solid with an excess of an alkali;B. sintering the said mixture;C. leaching the sintered product obtained with an aqueous solution;D. cementation of the gallium present in the resulting squeous solution with a metal more electropositive than gallium; andE. collecting the solid gallium precipitate obtained by cementation.

Abstract: This invention relates to a process for the separation and purification of platinum group metals and particularly platinum, rhodium and iridium. Essentially the platinum group metals are present as salts dissolved in an aqueous solution and the process for separating and purifying the platinum group metals comprises, according to one embodiment of the invention, the following steps:A. adjusting the pH, as necessary, to provide an acidic solution;B. contacting the acidic solution with a reducing agent to effect the reduction of iridium, that is, Ir(IV) to Ir(III);c. contacting the reduced solution with a nitrogen containing or organic compound selected from the group consisting of secondary amines, tertiary amines, and quaternary ammonium compounds;D. removing from contact with the solution an organic phase containing substantially all of the platinum present in association with the nitrogen-containing organic compound used in step (c);E.