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Resource and production technologies for scandium
Published in Natalia Yakovleva, Edmund Nickless, Routledge Handbook of the Extractive Industries and Sustainable Development, 2022
Scandium (Sc, atomic number 21) is classified as a rare earth metal (REM), along with yttrium (Y, atomic number 39) and the lanthanides (lanthanum (La), atomic number 57 to lutetium (Lu), atomic number 71). The physical and chemical properties of scandium, its content of the Earth’s crust, and its approximate price, along with other major REMs (La, cerium (Ce), praseodymium (Pr), neodymium (Nd), and samarium (Sm)) and some selected elements (iron (Fe), aluminum (Al), and titanium (Ti)), are shown in Table 15.1 (Taylor, 1964; Barin, 1993; Japan Inst. Metals, 2004; Meija et al., 2016; Alumu Publishing, 2019; U.S. Geological Survey, 2020). Scandium metal has a low density and is chemically reactive. The scandium compounds possess unique chemical and magnetic characteristics (Daane, 1961; Iyatomi and Nanjo, 1989). Although the content of scandium in the Earth’s crust is at a similar level to other rare earth elements, the prices of scandium metal and scandium oxide are considerably higher than those of other rare earth metals and rare earth oxides.
Sc, 21]
Published in Alina Kabata-Pendias, Barbara Szteke, Trace Elements in Abiotic and Biotic Environments, 2015
Alina Kabata-Pendias, Barbara Szteke
Scandium (Sc) is a silvery-white transition metal of group 3 in the periodic table of elements, with properties similar to Al and Y. Its mean concentration in the Earth’s crust is estimated to be 11 mg/kg, but also the range of 16–30 mg/kg is given. In higher amounts, it may be accumulated in mafic igneous rocks and argillaceous sediments. Its lowest contents, <5 mg/kg, are in calcareous rocks. Some organic raw materials, such as coal, peat, and crude oil, may accumulate elevated Sc amounts, up to 100 mg/kg ash weight (AW). Its mean content in the U.S. coal is 4.2 mg/kg, but may be elevated up to 100 mg/kg (Finkelman 1999). Its level in fly ash is up to about 5 mg/kg, mainly after burning lignite coal.
Processing Technology for Extraction of Scandium(III) from Secondary Sources – A Comprehensive Approach
Published in Abhilash, Ata Akcil, Critical and Rare Earth Elements, 2019
Pankaj Kumar Parhi, Saroj Sekhar Behera, Debadutta Das, Pramila Kumari Misra
The demand for scandium in 21st century is increasing due to its wide ranging applications in aerospace, electronics, nuclear industry, super-important materials, and special alloys [Li et al., 2018a, Nie et al., 2018 & Bell, 2015]. Due to the close resemblance of the physical and chemical property of scandium with core rare earth metals, it is a light rare earth element (REE), though in the periodic table it is found in 3d transition series [Chakhmouradian and Wall 2012]. In general, it occurs in trace amounts and is the 31st abundant element in the earth’s crust, with an average concentration of ~22 ppm [Kaya and Topkaya, 2015]. Scandium, in general, coexists with the minerals of aluminum, nickel, cobalt, and tungsten in trace amounts [Binnemans et al., 2015, Wang et al., 2013, Zhang et al., 2016 & Zhao et al., 2016]. Scandium is a minor element in rare earth minerals including yttrium and thorium. A major source of scandium has been reported to be as a by-product of other mineral processing. The content of scandium oxide is reported to be over 0.5% in rare earth minerals, including uran-othorite, wolframite, and ilmenite, along with other rare earth metals [Yang et al., 1995]. Therefore, its extraction and separation from these sources is not only difficult but also not economical. Owing to its scarcity and difficult extraction, scandium is found as a rare and expensive metal. At present, the cost of highly pure Sc2O3 (99.9%) is ~1400 USD/kg. Thus, there is a huge challenge facing metallurgists to develop a suitable and promising technology for the selective recovery of scandium from the above-mentioned minerals.
A systematic study on extraction and separation of scandium using phosphinic acid by both solvent extraction and hollow fibre membrane
Published in Mineral Processing and Extractive Metallurgy, 2022
Solvent extraction is the most common method for extraction of scandium which often associated with various complications such as multi-stage cycles, extractant loss, formation of stable emulsion and crud etc. In this investigation also, emulsion was formed during the preliminary experiments for which p-nonylphenol was added to the organic phase to overcome the problem. In supported liquid membrane technique there is no such emulsion formation. Scandium is a highly precious metal associated with some of the industrial wastes and as the concentration of scandium is less, hollow fibre membrane technique can be effectively used for its recovery simultaneously purifying the waste for disposal. Therefore, in this study the extraction behaviour of scandium with Cyanex 272 from hydrochloric acid medium using hollow fibre supported liquid membrane (HFSLM) was carried out and compared with solvent extraction.
Extractive Separation of Scandium from Strongly Alkaline Solution by Quaternary Ammonium Salt
Published in Solvent Extraction and Ion Exchange, 2020
H. E. Rizk, Y. A. El-Nadi, N. E. El-Hefny
Scandium is an element of light atomic weight. It exists in solids as an ionized form Sc(II) and in scarcer state as atomic Sc(I).[1] The stable oxidation state of scandium in aqueous solution is Sc(III).[2] Scandium is a rare metal which difficult to separate due to the deficiency of an appropriate reagent.[3] Scandium is the 31st most abundant element in the earth’s crust.[4] Scandium is a rare element and is a very expensive metal due to its scarcity and to the rather complicated metallurgical processes for its purification and recovery.[5] Scandium is used in a variety of applications, including metallurgical, ceramic, catalytic, electronic, lighting, and nuclear areas.[2] Thus, it can be used as an alloying metal for aluminum, as well as scandium(III) triflate is a recyclable Lewis acid catalyst used for the production of fine chemicals.[6] Scandium metal is included as a major component in solid oxide fuel cells owing to its extraordinarily salient features like high oxygen–ion conductivity property in the form of Sc2O3–stabilized ZrO2 materials.[7] The metal is also used in some types of neutron generators as a neutron filter because it is transparent to 2 keV neutrons but stops all other energy neutrons.[2]
Efficient Selective Extraction of Scandium from Red Mud
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Wei Ding, Shenxu Bao, Yimin Zhang, Junhui Xiao
Scandium (Sc) is one of the most important rare-earth elements (REEs) which is a crucial element for different industrial sectors on Earth (Xiao et al. 2020a). The average abundance of scandium in the crust is about 6 × 10−6, which is equivalent to that of beryllium, boron, strontium, tin, arsenic, and tungsten (Naboychenko, Murashova and Neikov 2009). In nature, scandium is widely dispersed in various silicate minerals and scandium-containing minerals, and it rarely forms a significant concentration (ore deposit). This makes it complicated and impractical to extract scandium from ore with complex composition and extremely low content. Therefore, it will be supplied mostly from scandium recovery from secondary sources and less from mining.