Abstract:
Monro & Gibbs (1) have described a Process for the extraction from Taranaki ironsand, of approximately 90% of the metals, vanadium and titanium, which are present to the extent of 0.3% and 9% respectively. Their method was to fuse at 800'C a mixture of 1 part sand, 2 parts Ca0, 2 parts CaCl2, and since the vanadium and titanium fusion products were water insoluble, to extract the melt with acid. On this account the method is unacceptable as a commercial proposition and it was in the hope of substituting a cheaper treatment of the fusion product that the following work was undertaken.
According to Wylie (2) the titanium occurs as ilmenite entangled in magnetite or possibly as 'titaniferrous magnetite' in which titanium partially replaces iron in the crystal lattice. No previous workers have commented on the nature of the vanadium compound in the sand, but the failure of all attempts to separate it from iron by magnetic concentration after grinding to a powder, indicates that it is in close combination with the magnetite if not in solid solution. Any fusion pretreatment of the sand must therefore decompose these complexes and either render the iron separable by magnetic means or the titanium and vanadium as compounds soluble in some suitable reagent, preferably water.
In such fusions it is important to consider the oxidation or reduction factors present, since these will determine the valence state and consequently will have a marked influence on the chemistry of titanium and especially of vanadium in that their acidic or basic properties will predominate accordingly as the conditions are oxidising or reducing. For optimum extraction therefore due regard must be paid to the valence state demanded by a specific fusion mixture.
