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Rb, 37]
Published in Alina Kabata-Pendias, Barbara Szteke, Trace Elements in Abiotic and Biotic Environments, 2015
Alina Kabata-Pendias, Barbara Szteke
The common oxidation state of Rb is +1, but may also be from +2 to +6. It is highly reactive and rapidly oxidized in air, and forms monoxide compounds: Rb2O, Rb6O, Rb9O2, and RbO2, in excess of oxygen in media. It also easily forms salts with halides (e.g., RbBr, RbF, Rbl). There are no minerals in which Rb is the predominant metal. It is associated with K minerals and may be concentrated in pegmatites. Lepidolite (mineral of mica group) is considered the principal ore mineral of Rb and contains up to 3.5% Rb oxides.
Research Progress in Flotation Collectors for Lepidolite Mineral: An Overview
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Lepidolite contains potassium and lithium, an integral element of aluminosilicate minerals with the T-O-T (tetrahedron-octahedron-tetrahedron) layer structures. Due to the fact that lepidolite usually contains a large amount of Rb+, Cs+, and Na+ as substitutes for K+ (Sahoo et al. 2022), it is often accompanied by the recovery of rubidium when extracting lithium. Its chemical composition can be formulated as K{Li2-xAl1+x[Al2xSi4-2xO10](F, OH)2}(x: 0 ~ 0.5) (Colton 1957; Korbel, Filippova, and Filippov 2023; Tian et al. 2020; Yan et al. 2012). Due to its good mobility and solubility, K+ and Li+ ions can be easily released from the lepidolite bulk into aqueous solutions. Thus, lepidolite particles load negative charges even at pH 2.0–3.0.
Beneficiation of a Nigerian lepidolite ore by sulfuric acid leaching
Published in Mineral Processing and Extractive Metallurgy, 2023
Daud T. Olaoluwa, Alafara A. Baba, Aboyeji L. Oyewole
With the majority of lithium production coming from brine, lithium mineral exploration must be upscaled especially with the largely unaccounted deposits of lithium minerals such as lepidolite, spodumene, petalite and montebrasite in the Nigerian mineralised pegmatites which exist in a broad belt, extending from Ago-Iwoye in the southwest to Bauchi in the northeast of the country, a linear distance of more than 400 km (Garba 2003; Akintola and Adekeye 2008). Of all these pegmatitic lithium minerals, lepidolite ores are of importance because of their widespread distribution, the characteristic of being poor in iron and the additional content of rare metals including rubidium and caesium (Ogorodova et al. 2005; Jandová et al. 2010; Yan et al. 2012a, 2012b; Lee 2015). Consequently, many hydrometallurgical processing routes have been proposed for beneficiating lithium minerals. These include chemical leaching consisting of unit operations utilising different salts or solvents or combination of salts and solvents such as salt roasting and water leaching (Chen et al. 2011; Yan et al. 2012a; Luong et al. 2013 and Baba et al. 2022), combination leaching with HF and H2SO4 (Wang et al. 2020), and autoclave H2SO4 leaching (Amer 2008).
Lithium recovery from mechanically activated mixtures of lepidolite and sodium sulfate
Published in Mineral Processing and Extractive Metallurgy, 2021
Nader Setoudeh, Ataollah Nosrati, Nicholas J. Welham
Lithium can be produced from a variety of natural mineral sources and the most abundant lithium containing rocks/minerals are the pegmatites which contain the minerals spodumene (LiAlSi2O6) and petalite (LiAlSi3O8) (Meshram et al. 2014). There are also several lithium bearing micas, the most abundant of which are lepidolite (LiKAl2F2Si3O9) and zinnwaldite (LiKFeAl2F2Si3O10). The mineral name lepidolite is now discredited and the mineral is considered to be part of the polylithionite (KLi2Al(Si4O10)(F,OH)2)–trilithionite (KLi1.5Al1.5AlSi3O10F2) group (Paukov et al. 2007). The extraction of lithium from lepidolite has been recently investigated due to its comparatively wide distribution, low iron content (compared to zinnwaldite) and the additional attraction of valuable by–products such as Rb and Cs (Luong et al. 2013; Vieceli et al. 2017a).