Titaniferous rock

In magnetic iron ore, magnetite, the V-content can be 1-2%. This is the case in South Africa. The Bushveld-complex in Transvaal is a very large magmatic magnetite formation. In the eastern and western parts of this complex, there are heavy deposits of titaniferous rock with a vanadium content of up to 2%. That is one of the biggest vanadium reserves of the world. China is, however, reported to have the greatest reserves. The uses estimates that the world vanadium reserve base is sufficient to meet vanadium demand for many hundreds of years. 

Two different pathways of formation are possible (Stanjek, 2000). One route involves aerial oxidation of lithogenic magnetite as suggested for Brazilian Oxisols on basic igneous rocks. The mechanism of this topotactic reaction is described in Chapter 14. These maghemites are usually titaniferous as are the magnetites from which they are derived (see Chap. 15) and almost free from or very low in Al (Allan et al., 1989). Their unit cell size is a function of the residual Fe" and the Ti content. 

In Great Britain vanadium has been found associated with the lead ores at Wanlockhead, in the Lead Hills, Dumfriesshire, as vanadinite,a and associated with the copper deposits at Alderley Edge and at Mottram St. Andrews, Cheshire, as mottramite. The latter was at one time mined and treated for its vanadium, but commercially profitable supplies of this ore have now given out. Vanadium has also been reported to occur in titaniferous iron ores at Antrim,3 and in rocks at Wicklow and Giant s Causeway.4... 

Fig. 3.1.4. Rock phosphate from Malpelo Island, D.F., Colombia. The porous rock is essentially a mixture of strengite and phosphosiderite, but contains relict oxides (titaniferous magnetite). Magnification 33x. Reproduced with permission (McConnell, 1943).

Fig. 13.49 The concentration of vanadium in the rocks of the Dufek Massif increases linearly with increasing modal concentrations of pyroxene. The relationship is expressed by Eq. 13.1 in the text. The highest sample in the stratigraphy of the Dufek intrusion at 1,798 m has an excessive vanadium concentration of 460 ppm because it contains titaniferous magnetite at a modal concentration of 3% by volume. The concentration of vanadium in the oxide is 0.63% by weight (Appendix 13.6.10) (Data by Ford et al. 1983)...

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