China
Africa
Explore chapters and articles related to this topic
Geochemical Fractionation and Availability of Vanadium in Soils
Published in Jörg Rinklebe, Vanadium in Soils and Plants, 2023
Cho-Yin Wu, Maki Asano, Zeng-Yei Hseu
Vanadium is the fifth most abundant element among all transitional metals and ranks 22nd among all discovered elements in the Earth’s crust, with an average content of 97 mg/kg, which is two times higher than copper and 10 times higher than lead (Nriagu, 1998; McDonough and Sun, 1995). Vanadium exists in over 80 minerals, which can be divided into following groups: sulfides (e.g., patronite and sulvanite), sulfates (e.g., minisragrite and cheremnykhite), silicates (e.g., roscoelite), oxides (e.g., navajoite and montroseite), phosphates (e.g., vanadinite) and vanadates (e.g., chervetite, tyuyamunite, carnotite and volborthite) (Nriagu, 1998). In addition, vanadium associates in nearly 70 minerals such as pyroxenes, hornblende, biotite and magnetite as an admixture due to the sorption properties of vanadium oxides (Kabata-Pendias, 2011).
Leaching with Acids
Published in C. K. Gupta, T. K. Mukherjee, Hydrometallurgy in Extraction Processes, 2019
Uranium occurs in minerals (1) as an essential constituent in what is termed uranium minerals and (2) in partial substitution for some other element such as apatite, monazite, zircon, xenotime, titanite, and pyrochlore. The very limited substitution by uranium in minerals of the second type militates against these minerals being treated solely for their uranium content. However, they do offer a source of uranium as a by-product, for example, in the phosphate industry. The uranium minerals are grouped into two categories depending on their associated uranium valence states. Minerals in which uranium is tetravalent are generally referred to as primary, and those in which uranium is hexavalent are called secondary. The most important primary minerals are pitchblende, uraninite, and davidite. Carnotite, autenite, torbemite, and tyuyamunite are the more important secondary minerals.
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 ore mineral assemblage in unoxidised mineralised zones consists mainly of uraninite (UO2), coffinite [U(SiO4)1-x(OH)4x], vanadian illite-smectite, roscoelite [K(V3+, Al)2(AlSi3O10)(OH)2], vanadian chlorite, montroseite [(V3+, Fe3+)O(OH)] and doloresite [V4+3O4(OH)4] (Meunier 1994; Shawe 2011). Where mineralised zones came into contact with oxidising meteoric waters, the original uranium mineralogy was at least partially converted to secondary uranium-vanadium bearing minerals (Chenoweth 1981; Shawe 2011) such as carnotite [K2(UO2)2(VO4)2·3H2O], tyuyamunite [Ca(UO2)2(VO4)2·6(H2O)] and pascoite [Ca2Ca(V10O28)·17H2O]. Vanadium-bearing clays, chlorite, and micas are the main vanadium minerals in both oxidised and unoxidised portions of Salt Wash category deposits.