VanadiumCorp and Electrochem are expanding phase II trial production with testing of global vanadium, iron & titanium slags from the steel industry as feedstock at Electrochem facilities in Boucherville, Quebec, Canada

V slag process

Vanadium from the titaniferous magnetite ores of Russia and China and South Africa is extracted as a co-product in steelmaking. In China and Russia the iron is produced in a blast furnace but in South Africa the iron is produced by a process involving the pre-reduction of the magnetite with powdered coal in a rotary kiln followed by reduction in a submerged arc electric furnace.  Vanadium bearing coproduct slag is generated during steel production from iron sands in New Zealand in a process similar to the South African process.

The iron from these operations contains about 1.5% vanadium which is removed as slag by low temperature treatment with oxygen. In China this is carried out by spray refining, while in South Africa it is done in a shaking ladle and in Russia a special oxygen steel converter is used.

The slag from South Africa contains up to 25% V2O5 whereas the slag from China and Russia contains between 14% and 22%. The V2O5 is extracted from the slags by a roast-leach process in which the slags are roasted in kilns or in multi-hearth furnaces with sodium carbonate, chloride or sulphate (or lime in Russia). This produces sodium vanadates which are leached into an aqueous phase with water. Ammonium vanadates are precipitated from this solution by addition of ammonia and sulphuric acid to control the pH.

The ammonia is removed and the vanadate converted to various oxides by heating under controlled conditions which are varied according to the oxide required. Fused flake V2O5 is produced by decomposing the vanadates in a furnace and melting the resulting V2O5 to liquid phase and then casting onto a chilling wheel.  Vanadium oxide powders are produced by the solid state decomposition of the vanadates in a controlled environment.  In some cases liquid-liquid ion exchange/solvent extraction processes are utilized to produce high purity vanadium oxide powders.

Vanadium oxides are used for the production of ferrovanadium and vanadium-aluminium alloys required for the addition of vanadium to steel and titanium respectively. Ammonium vanadates and high purity vanadium oxide powders are used for the production of downstream vanadium chemicals..

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