Scandium Recovery from an Ammonium Fluoride Strip Liquor by Anti-Solvent Crystallization

Abstract

In this study, the crystallization of scandium from ammonium fluoride strip liquor, obtained by solvent extraction, was investigated using an anti-solvent crystallization technique. Acetone, ethanol, methanol and isopropanol were added individually to the strip liquor as the anti-solvent and scandium was precipitated and obtained in the form of (NH 4 ) 3 ScF 6 crystals. The results show that scandium can be effectively crystallized from the strip liquor to obtain an intermediate, marketable scandium product. Yields greater than 98% were obtained using an anti-solvent to strip liquor volumetric ratio of 0.8. Acetone had the least performance at lower anti-solvent to strip liquor volumetric ratios, possibly due to its limited H bonding capability with water molecules when compared to alcohols.

Precipitation and Crystallization Used in the Production of Metal Salts for Li-Ion Battery Materials: A Review

“…Physical change e.g., precipitation of the colloidal particles in wastewater by adding flocculant. e.g., evaporative crystallization to produce (NH 4 ) 10 (H 2 W 12 O 42 )•4H 2 O (APT) [8], eutectic freeze crystallization to produce CuSO 4 •5H 2 O [16], antisolvent precipitation of REE sulfate hydrates [17], antisolvent crystallization of (NH 4 ) 3 ScF 6 [18]. Aluminum removal by KAl(SO 4 ) 2 •12H 2 O crystallization [19].…”

“…The literature on antisolvent crystallization contains numerous reports of potential organic solvents that are able to lower the solubility of some inorganic solutes. These include ethanol, acetic acid, 2-propanol, acetone, glycine, methanol, tert-butanol, methyl-ethyl-ketone (MEK), ethyl-acetate and isopropyl-acetate [17,18,59,61]. Recently, antisolvent crystallization has been examined for use in the selective recovery of critical metals from aqueous solutions.…”

Sustainable Utilization of Metals-Processing, Recovery and Recycling

“…Additionally, their ignoble character, as well as their low concentration in recycling materials cause a low recycling rate of these metals, awarding them the status of "critical metals". The research of this increasingly important material group will be discussed in this Special Issue in seven research papers [1][2][3][4][5][6][7].…”

Valorization of Rare Earth Elements from a Steenstrupine Concentrate Via a Combined Hydrometallurgical and Pyrometallurgical Method

“…Generally, from 2013, several research projects have started in Europe (EREAN, REDMUD; EURARE, SCALE and REMOVAL) in order to study the prevention of silica gel formation and reach a high extraction of rare earth elements from eudialyte, red mud and slags after the smelting of red mud [16][17][18][19][20]. This work belongs to the EURARE project that focuses on producing REE within Europe and reducing the external supply [16].…”

“…This work belongs to the EURARE project that focuses on producing REE within Europe and reducing the external supply [16]. An extraction of scandium from red mud was studied by Alkan et al [16][17][18][19][20], confirming that dry digestion was successfully used to prevent a silica gel formation, simultaneously providing a high leaching efficiency of the rare earth elements.…”