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Optimum fluxing, smelting and leaching practices have been determined for maximising the recovery of alumina and soda, but not iron, from a slag produced by oxidative smelting of bauxite residue at 1400°C. The rate and extent of dissolution of alumina and soda increased in a water leach as the CaO/SiO2 ratio in the slag was increased from 0·1 to 2 by the addition of calcium carbonate to the dried bauxite residue. A water leach at 60°C, extracted 55% of the Al and 90% of the Na at 20 wt-% solids and 50 and 75% respectively, at 50 wt-% solids. Liquors containing ∼43 g L–1 Al and Na were obtained from leaches at 50 wt-% solids. By recycling this liquor in two further leaches on fresh slag at 50 wt-% solids, levels of 130 g L–1 Al and 125 g L–1 Na in solution were achieved. At these concentrations of alumina and soda, it is expected that the leach liquor should be suitable for recycling to the Bayer process. The dissolution of the alumina and soda from the slag was shown to be due to the leaching of a...