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: The specification discloses a process for substantially reducing the radioactivity of heavy mineral concentrates or mineral mixtures. The process comprises the removal of radioactive minerals present in the heavy mineral concentrate or mixture by a selective flotation procedure. The process yields a single flotation fraction containing the radioactive minerals.