Abstract: A process for leaching an ore containing sulfidic copper-containing minerals includes carrying out an aerated oxidizing leach of a part of the ore and producing an acidic leach liquor containing ferrous ions, ferric ions, and copper ions in solution. The process also includes carrying out a leach of another part of the ore using the leach liquor under conditions that minimize reactions with a source of iron in the ore and producing a leach liquor containing copper ions in solution. The process further includes recovering copper from the leach liquor.

Abstract: A process for leaching an ore containing sulphidic copper-containing minerals is disclosed. The process includes carrying out an aerated oxidising leach of a part of the ore and causing reactions with a source of iron such as pyrite in the ore and producing an acidic leach liquor containing ferrous ions, ferric ions, and copper ions in solution. The process also includes carrying out a leach of another part of the ore using the leach liquor produced in step (a) under conditions that minimise reactions with a source of iron such as pyrite in the ore and producing a leach liquor containing copper ions in solution.

Abstract: An industrially realistic process for upgrading of titaniferous materials is disclosed. The process comprises the following steps: (i) a pretreatment which has the effect of rendering silica amenable to leaching under the particular conditions of a subsequent leach, and (ii) an aqueous leach in the presence of an acid, the conditions of which are chosen such that silica which enters solution is not hydrolysed or precipitated as a silicate. The pretreatment step (i) may comprise alkaline leaching, roasting or smelting. The leaching step (ii) may be conducted at low solids densities.

Abstract: A process for upgrading of titaniferous material containing silica, including pretreating the titaniferous material by alkaline leaching to precipitate the silica as an aluminosilicate which is amenable to further leaching. Subsequently, the pretreated titaniferous material is leached under acid conditions, causing the silica to enter solution under conditions such that the silica is not hydrolysed or precipitated as a silicate.

Abstract: The application discloses a process for upgrading a titaniferous material by removal of impurities contained in the material especially radionuclides. The process involves heating the titaniferous material to a temperature of less than 1300° C. to form a solid titaniferous phase and a liquid oxide or glassy phase in the presence of a material that promotes the formations of such phases, cooling the product at a rate that maintains the glassy phase in an amorphous state and leaching the solidified material with an acid or an alkali to remove the impurities. Materials that promote the formation of the desired phases include compounds of alkali metals and boron. Examples include borax, caustic soda, soda ash and silica.

Abstract: The application discloses a process for upgrading a titaniferous material by removal of impurities contained in the material especially radionuclides. The process involves heating the titaniferous material to a temperature of less than 1300° C. to form a solid titaniferous phase and a liquid oxide or glassy phase in the presence of a material that promotes the formations of such phases, cooling the product at a rate that maintains the glassy phase in an amorphous state and leaching the solidified material with an acid or an alkali to remove the impurities. Materials that promote the formation of the desired phases include compounds of alkali metals and boron. Examples include borax, caustic soda, soda ash and silica.

Abstract: A process for the removal of reactive silica from a feedstock to the digestion step of the Bayer process for the manufacture of alumina, in which (a) the feedstock is contacted with a caustic liquor under process conditions which result in dissolving and stabilizing at least 50% of the silica into solution at a level of at least 3 gpL and without significant precipitation from solution of dissolved silica, (b) the silica bearing liquor is separated from solid residue of step (a) under conditions which do not promote significant precipitation of the silica; and (c) aluminosilicates are precipitated from the separated silica bearing liquor from step (b), to form a solid aluminosilicate product which is free of a majority of all other components of the feedstock.

Abstract: A process for increasing the particles size of fines of a titaniferous mineral containing more that 45% by weight of titanium. The process comprises mixing the fines with a binding agent and water to produce an agglomerate. The agglomerate is then dried and sintered.

Abstract: A process for alkaline leaching of a titaniferous material containing silica and alumina impurities in which spent leachant is recycled by treating to remove the silica and alumina impurities therefrom, by heating, maintaining the leachant at leaching temperature, or treating with an additive. The removal of the silica and alumina impurities by the method of the invention enables further use of the leachant.

Abstract: A process for forming an aqueous chloride leachant from a spent aqueous chloride leach liquor which process comprises passing a spent aqueous chloride leach liquor and gases containing hydrogen chloride through a preconcentrator to form a concentrated aqueous chloride leach liquor by partial evaporation of water therefrom and absorption of hydrogen chloride; withdrawing a portion of the concentrated aqueous chloride leach liquor; roasting the remainder of the concentrated aqueous chloride leach liquor to generate a metal oxide, and gases containing hydrogen chloride; and passing the gases containing hydrogen chloride to the preconcentrator.

Abstract: A process for removing impurities from a titaniferous material that has been subjected to thermal reduction and which includes a titaniferous phase of general formula M.sub.3 O.sub.5. The thermally reduced titaniferous material is subjected to a secondary heat treatment to covert the M.sub.3 O.sub.5 phase to a more readily leachable M.sub.2 O.sub.3 phase. This material is then cooled and leached in an aqueous acid solution containing hydrochloric acid or sulfuric acid, and the leachate is separated from the titaniferous material to form a purified titaniferous material.

Abstract: A process for producing a zirconia beating opacifier is disclosed. The process comprising the steps of: (I) heat treatment of a zirconia bearing material comprising heating the zirconia bearing material in the presence of an additive to form a heat modified product having one or more phases which, when incorporated in a glaze and the glaze fired, exhibit opacifying characteristics; and (ii) cooling the heat modified product to produce a product which can be used for imparting opacity.