Recovering Scandium from Scandium Rough Concentrate Using Roasting-Hydrolysis-Leaching Process

Junhui Xiao,Yang Peng,Kai Zou,Zhen Wang,Wei Ding,Tao Chen

doi:10.3390/pr8030365

Junhui Xiao, Yang Peng + Show 4 more

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https://doi.org/10.3390/pr8030365

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Abstract

In this study, a roasting-hydrolysis-acid leaching process is used to extract scandium from the scandium rough concentrate. The scandium rough concentrate containing Sc2O3 of 76.98 g/t was obtained by magnetic separation, gravity separation, and electric separation from Sc-bearing Vi-Ti magnetite tailings in the Panxi area of China. The majority of scandium in scandium rough concentrate mainly occurs in diopside, titanopyroxene, montmorillonite, chlorite, talc, aluminosilicate minerals, and isomorphism. Sodium salt and scandium coarse concentrate are added into the roasting furnace for roasting, which makes the fusion reaction of silicon, aluminum and sodium salt to produce soluble salts such as sodium silicate and sodium metaaluminate. Scandium is further recovered from the hydrolysis residue by acid leaching. Test results show scandium leaching recovery of 95.12% and the acid leaching residue with Sc2O3 content of 8.12 g/t are obtained, while the extraction of scandium is obvious. There is no obvious peak value of Scandium spectrum in hydrochloric acid leach residue. Most of scandium in hydrolytic residue is dissolved into Sc3+ and enters into the liquid phase. The main minerals in leach residue are perovskite, ferric silicate, and olivine.

Highlights

In the crust, the specific minerals of scandium are very rare
The minerals closely related to scandium are mainly titanaugite, plagioclase, diopside, chlorite, and mica
Al2 O3 are removed in advance by roasting-hydrolysis to decrease impurities in Scandium lixivium

Summary

Introduction

The specific minerals of scandium are very rare. there are only small economic reserves of Sc-bearing minerals including only thortveitite (Sc,Y) Si2 O7 , scandium phosphiteScPO4 ·2H2 O, bazzite Be3 (Sc,Al) Si6 O18 , titanium silicate mineral Sc(Nb,Ti,Si) O5 , and befanamite (Sc,Zr) Si2 O7 , etc. The specific minerals of scandium are very rare. There are only small economic reserves of Sc-bearing minerals including only thortveitite (Sc,Y) Si2 O7 , scandium phosphite. Scandium mostly occurs in ilmenite, zircon, bauxite, rare earth ore, ilmenite, V-Ti magnetite, tungsten ore, tin ore, uranium ore, coal, and other minerals [1]. There are more than 800 kinds of scandium bearing minerals, which are complex in mineral composition and low in scandium content. They are distributed in other minerals in isomorphic or adsorption states, making the enrichment, separation, and extraction of high-purity scandium quite complex [2]. Scandium and its compounds have many excellent properties and are widely used in national defense, electric light source, aerospace, chemical industry, metallurgy, and other fields [3]

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