Abstract: The invention relates to the production of desirably purified refractory metal borides. The method can be used to purify even commercially available material. Careful attention is directed to the oxygen impurity level of the refractory metal boride and such will usually be maximized at a very low level. Critical attention is directed to the oxygen to carbon molar ratio. Heating of impure materials, typically presented in consolidated form and having constituent adjustments in accordance with invention principles, can lead to the preparation of products of highly desirable density, on the one hand, and prepare products of extremely low contamination levels, on the other hand.

Abstract: In an aluminium reduction cell including a cell lining and embedded therein at least one cathode current collector including a high temperature section comprising an electrically conducting refractory material such as titanium diboride, generally in conjunction with molten aluminium metal, corrosion is a problem. The invention provides a substance to protect the collector section. The substance may be a liquid impermeable layer e.g. particulate material impregnated with a molten fluoride-or chloride-containing salt mixture; for a getter such as particulate aluminium to react chemically with gaseous corrosive species. Combinations of these substances may be used, optionally in conjunction with a solid layer such as an alumina or aluminium metal tube.

Abstract: An electrode having a lead base and a catalyst is manufactured by (a) compressing titanium sponge particles so as to consolidate them to a coherent porous layer, (b) applying the catalyst to the titanium sponge particles, and (c) fixing the layer of consolidated sponge particles to the lead base. The catalyst is formed on the titanium sponge particles before or after their consolidation to a coherent layer. This layer may be produced and fixed to the base in a single compressing and fixing step combining (a) and (c). Oxygen is anodically evolved at a reduced, stable potential by means of this electrode, so that it can be usefully applied as an anode in processes for electrowinning metals from acid electrolytes.