Interfacial Structure Change and Selective Dissolution of Columbite–(Fe) Mineral during HF Acid Leaching

Minerals

Shaobo Zheng¹  Fanxi Yang²  Cang Zhou²  Dan Wang²  Qiuju Li³ 

[1] Key Laboratory of Modern Metallurgy and Material Preparation, Shanghai University, Shanghai 200444, China;School of Material Science and Engineering, Shanghai University, Shanghai 200444, China;State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200444, China;

关键词: columbite–(Fe);    X-ray photoelectron spectroscopy;    DFT;    acid leaching;    charge transfer;   

DOI  :  10.3390/min11020146

来源: DOAJ

【 摘 要 】

The goal of the paper is to study the charge transfer and reactions at the columbite-(Fe) (FeNb₂O₆) mineral surface during the HF leaching process. In this paper, X-ray photoelectron spectroscopy (XPS), leaching experiments, and density functional theory (DFT) calculations were used to study the surface element adsorption, charge distribution, chemical state, and energy changes of the mineral surface during the process of leaching columbite–(Fe) with different concentrations of hydrofluoric acid. The results showed that as the concentration of F atoms was increased during the acid leaching process, the Nb–O bond was more likely to be broken than the Fe–O bond; the amount of charge transferred from Nb atom to F atom (0.78 e–0.94 e/atom) was greater than that from Fe atom to the F atom (0.25 e–0.28 e/atom), so it was determined that compared to Fe atoms, it was easier for the Nb atoms to bind to F. The results of XPS analysis showed that the electron binding energies of Nb⁵⁺–O, Fe³⁺–O, and Fe²⁺–O bonds on the mineral surface increased sequentially, and the M–O bond broke during the acid leaching process, forming more stable M–F bonds. Therefore, the Nb⁵⁺–F bonds were easier to form a stable structure. Combined with the ICP results, it was found that in the filtrate after 5M HF and 10M HF acid leaching minerals, c(Nb)/c(Fe) were 2.69 and 2.95, respectively, and the concentration ratio of Nb to Fe element in the mineral was 2 which was lower than 2.69 and 2.95, confirming the result of DFT calculation and illustrating that Nb atoms in columbite-(Fe) mineral were more soluble than Fe atoms.

【 授权许可】

Unknown