Abstract: A process for the production of high-purity zirconia from dissociated zircon or other zirconiferous material is disclosed. The process includes leaching of the zirconiferous material with concentrated sulphuric acid and continuously removing the water formed during leaching to maintain the concentration of sulphuric acid at a substantially constant level.

Abstract: A process for the recovery of phosphate values from a phosphate ore, wherein the ore is leached with a mixture comprising water, sulphur dioxide and an organic carbonyl compound; the leach liquor containing dissolved phosphate values and calcium hydroxysulphonate is separated from any gangue and other insoluble material; and the leach liquor is treated to recover therefrom a phosphate-rich product and at least part of the sulphur dioxide and the carbonyl compound; characterized in that the leaching is carried out under conditions such that substantially no calcium hydroxysulphonate is precipitated at the leaching stage.

Abstract: A process for obtaining anhydrous aluminium chloride from aluminium chloride hexahydrate comprises heating the hexahydrate at a temperature in the range 200.degree.-450.degree. C. until it is substantially dehydrated and reacting the dehydrated material at a temperature in the range 350.degree.-600.degree. C. with a gas mixture containing chlorine, carbon monoxide, carbon dioxide and hydrogen, to produce gaseous anhydrous aluminium chloride.