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: The specification discloses a process for stabilizing radionuclides extracted during the upgrading of minerals. The process comprises forming a composition of a radionuclide and a component and roasting the composition so that the component forms a crystalline phase having a structure that binds the radionuclides. Suitable components include a compound of a lanthanide and/or phosphorus and zirconia. Zirconia in its cubic form is useful in stabilizing uranium and thorium.

Abstract: The specification discloses a process for removing radionuclides from zircon. The process involves thermally decomposing the zircon in the presence of suitable additives, extracting the radionuclides chemically and recovering zirconia and silica. Suitable additives include fluxes, silica and any oxide capable of forming a silicate with silica when heated. Chemical treatments disclosed include leaching with mineral acids and strong organic acids. Methods of stabilizing the radionuclides extracted by leaching are also disclosed. One method involves spray roasting. Another method involves neutralization of leach liquor and recovery of radionuclide solids by filtration or other suitable liquid/solid separation techniques.

Abstract: The specification describes a process for producing synthetic rutile from a titaniferous ore or concentrate. The process involves three basic steps which are reduction, removal or iron by leaching or aeration and removal of other impurities by leaching in a solution of a strong mineral acid such as hydrochloric acid or sulphuric acid. The conditions of reduction are controlled to promote the formation of metallic iron, a major rutile phase and a minor impurity bearing phase. The minor impurity phase may be a metatitanate, an anosovite or a pseudobrookite. However, formation of a metatinatate is normally preferred. Suitable reductants include carbonaceous materials or hydrogen bearing gases such as natural gas or synthesis gas. The process is capable of removing more than 80% of each of the contained iron magnesium and manganese remaining as oxides after reduction. Substantial proportions of contained aluminum can also be removed.

Abstract: Accordingly the present invention provides a process for producing acid soluble titania which process comprises the steps of:(i) adding a manganese or magnesium compound to a titaniferous mineral if the mineral does not contain sufficient manganese and magnesium to satisfy the following relationship: ##EQU1## where a represents the percentage by weight of MgO contained in the mineral,b represents the percentage by weight of MnO contained in the mineral, andd represents the percentage by weight of TiO.sub.

Abstract: A smelting process of superior energy efficiency, particularly suitable for the extraction of zinc, but also of lead and copper from raw materials comprising sulphide concentrates, and oxidized metalliferous materials, is carried out by establishing at least one oxidation zone and at least one reduction zone in a furnace, each zone comprising a slag bath and a gas space; the gas spaces of the oxidation and reduction zones being separated by a partition; feeding raw materials comprising metal sulphides, together with fluxes, to the or each oxidation zone, and feeding oxygen or oxygen-rich gas into the slag bath in the or each oxidation zone to oxidize metal compounds therein and produce an off-gas containing SO.sub.