Issue |
Metall. Res. Technol.
Volume 116, Number 1, 2019
|
|
---|---|---|
Article Number | 114 | |
Number of page(s) | 11 | |
DOI | https://doi.org/10.1051/metal/2018040 | |
Published online | 25 January 2019 |
Regular Article
Study on recycling and leaching valuable elements from Bayan Obo tailings
1
School of Metallurgy, Northeastern University,
Shenyang
110819, PR China
2
Liaoning Key Laboratory of Recycling Science for Metallurgical Resources,
Shenyang
110819, PR China
* e-mail: neuyanghe@163.com
Received:
15
March
2018
Accepted:
3
May
2018
A novel process for recovering iron, niobium and scandium from Bayan Obo tailings has been developed. In this paper, the treatment of Bayan Obo tailings by Ca(OH)2-coal roasting and sulfuric acid leaching process was investigated. In the Ca(OH)2-coal roasting process, niobium-bearing minerals are converted to CaTiO3 structure of Ca(Ti0.8,Fe0.1,Nb0.1)O3 and Ca2Nb2O7 which are soluble in sulfuric acid. The pyroxene and amphibole that are Sc-bearing silicates are mainly decomposed and reduced into metallic iron which can be recycled by weak magnetic separation. Scandium in the silicates is converted to Sc2O3. In the sulfuric acid leaching process, Ca(Ti0.8,Fe0.1,Nb0.1)O3 and Ca2Nb2O7 are converted to Nb(OH)5 that could easily dissolve in sulfuric acid by dissociating into Nb(OH)4+ and OH− when Sc2O3 is dissolved into heat sulfuric acid. Bayan Obo tailings were roasted with Ca(OH)2-coal at elevated temperature, followed by magnetic separation and sulfuric acid leaching. The optimized experimental parameters are proposed as follows: Ca(OH)2-coal-tailings mass ratio of 20: 5: 100; roasting at 1200 °C for 2 h; the magnetic field (magnetic separation) of 270 mT; the liquid-solid ratio of 4:1 (ml/g); leaching at 245 °C for 1 h. Iron concentrate with a grade of 88.39% and a recovery rate of 91.92% is obtained. The leaching results show that the leaching rates of niobium and scandium could achieve 95.52% and 95.75%, respectively.
Key words: niobium and scandium / Ca(OH)2-coal / roasting / magnetic separation / sulfuric acid leaching
© EDP Sciences, 2019
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.