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Heavy Metals
Published in Abhik Gupta, Heavy Metal and Metalloid Contamination of Surface and Underground Water, 2020
Vanadium has an atomic number of 23, an atomic weight of 50.942, and a density of 6.11 g cm–3. The major ores of vanadium include patronite or vanadium sulfide, which occurs in Peru, and descloizite or lead-zinc vanadate, found in southern Africa. Vanadinite [Pb5(VO4)3Cl], roscoelite [K(V3+, Al)2(AlSi3O10)(OH)2], and carnotite [K2(UO)2(VO4)2·3H2O] are the other important vanadium-containing ores. Of these, carnotite is a radioactive mineral containing uranium. Other sources comprise crude petroleum, flue-gas deposits from oil-fired furnaces, and slags from ferrovanadium. The most important use of vanadium is in making ferrovanadium, which finds use in high-speed steel and tool-grade steel. Vanadium augments tensile strength and improves the rust resistance of steel. Several vanadium compounds including sulfates and tetrachlorides are used as mordant, silicates as catalysts, and dioxides and trioxides in metallurgy. Vanadium pentoxide (V2O5) is used as an industrial catalyst, in photography, textile, and ceramics, while ammonium metavanadate (NH4VO3) acts as a catalyst, in the photographic and textile industries, and as a reagent in analytical chemistry.
Vanadium as a critical material: economic geology with emphasis on market and the main deposit types
Published in Applied Earth Science, 2022
George J. Simandl, Suzanne Paradis
The spatial association between vanadium mineralisation and nonsulphide Pb-Zn deposits in combination with field observations, textures, and mineral paragenesis led to the conclusion that the vanadium mineralisation in the Otavi Mountainland was supergene in origin, a hypothesis supported by studies from Boni et al. (2007) and Kamona and Gunzel (2007). According to Bannister and Hey (1933) and Palache et al. (1951), the vanadate mineralisation of the Otavi Mountainland commonly consisted of mineral species belonging to the isomorphic series between descloizite [PbZn(VO4)(OH)] and mottramite [PbCu(VO4)(OH)] and to a lesser extent vanadinite [Pb5(XO4)3Cl], where X represents the elements P, As, and V (Figure 5(b); from Boni et al. 2007). Also in the Otavi Land area, the Abenab vanadium deposit, hosted by the carbonate rocks of the Maieberg Formation which belongs to the Tsumeb Supergroup, produced 1.85 million tonnes of ore averaging 1.03% V2O5 (Cairncross 1997). The deposit is described as a cylindrical breccia pipe consisting of descloizite and vanadinite cemented by calcite (Kamona and Gunzel 2007). Other examples of the vanadate-bearing deposits include Kabwe Mine (formerly known as ‘Broken Hill’), Zambia (Skerl 1934; Taylor 1954; Southwood et al. 2019) and Kihabe Zn–Pb–V prospect, Botswana (Mondillo et al. 2020). The Kabwe Mine and related processing plant operated from 1906 to 1994 and produced 0.8 million tonnes of Pb, 1.8 million tonnes of Zn with silver (79 tonnes), V2O5 (7820 tonnes), cadmium (235 tonnes) and copper (64 tonnes) as a byproduct (Kamona and Friedrich 2007). The Kabwe area in Zambia is currently considered as one of the most polluted sites in the world, due largely to wind dispersion of dust from extensive piles of slag (Baieta et al. 2021). Non-African examples are the St. Anthony mine in Arizona (644 tonnes of vanadium, 1934–44; Fischer 1975), and Los Lamentos and San Antonio mines in Mexico (211 tonnes of vanadium, 1938–40; Fischer 1975).