Basic extraction separation flowsheets of Chinese Baotou and Southern rare
earth resources
Fu-Xiang Cheng,1,2 Sheng Wu1,2, Chun-Sheng Liao1,2, Chun-Hua Yan1,*
1
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, PKU-HKU Joint Lab on Rare Earth Materials and
Bioinorganic Chemistry, Peking University, Beijing, China;
2
China Minmetals (Beijing) Research Institute of RE Co., Ltd, Beijing 100085, China.
* Corresponding author, email: yan@pku.edu.com
Acidic extractants are commonly used to separate rare earths, and saponification by basic
substances is usually necessary for the purpose of increasing and stabilizing the extraction
capacity of the acidic extractants. Meanwhile inorganic acids are demanded for both scrubbing
and stripping. Thus acids and bases are the main consumed chemicals, and the resulted salts are
the main pollution during rare earth separation processes. Currently due to the increasing
environmental concerns, the separation techniques of solvent extraction are tending to reduce both
consumption and emission of chemicals [1].
Hyperlink process has been proved in industrial practices to be able to dramatically reduce
both consumptions and emissions of chemicals during the multi-component extraction separations,
and therefore widely used in Chinese rare earth separation industry in the current time [1].
However, the theory for design of the new process was still insufficient. To determine the
theoretical minimum requirement of the base for saponification as well as the acid for scrubbing,
the terms of minimum amounts of extracting solvent and scrubbing agent solution (denoted as Smin
and Wmin respectively) are introduced. In the present articles, we will show a brief review of our
recent works [2,3] on development of the Theory of Countercurrent Extraction to determine the
Smin and Wmin of the hyperlink countercurrent unit, and subsequently introduce the principle to
design the basic flowsheets of extraction separation of both the Baotou and the ion-adsorptive rare
earth mines which are the main rare earth resources in China.
References:
[1] Liao, C.S., Wu, S., Cheng, F.X., Wang, S.L., Liu, Y., Zhang, B., Yan, C.H., (2013) Clean
separation technologies of rare earth resources in China, J. Rare Earths, 31(4), 331-336.
[2] Cheng, F.X., Wu, S., Liu, Y., Wang, S.L., Zhang, B., Liao, C.S., Yan, C.H., (2014) Minimum
amount of extracting solvent for AB/BC countercurrent separation using aqueous feed, Sep.
Purif. Technol., 131, 8-13.
[3] Cheng, F.X., Wu, S., Liu, Y, Wang, S.L., Zhang, B., Liao, C.S., Yan, C.H., (2014) Minimum
amount of extracting solvent of a separation of two rare earth components, Adv. Mater. Phys.
Chem., 4, 275-283.