Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6659093 | Hydrometallurgy | 2018 | 38 Pages |
Abstract
The simultaneous transformation and dissociation of minerals containing iron in reductive Bayer digestion of bauxite are important to separate iron minerals from red mud and thus reduce the waste solid disposal in alumina production. In order to better understand the reaction mechanism of iron and hematite in sodium aluminate solution, the phase composition, valence variation and micro-morphology of transformation products were studied by XRD, XPS, FT-IR and SEM respectively. The results show that the intermediate alumogoethite, α-Fe(1 â x)AlxOOH, preferentially forms by the reaction of HFeO2â and AlO2â and then converts to magnetite in Fe-Na2O-Al2O3-H2O system at digestion temperature of 533 K. Meanwhile, the transformation of hematite to magnetite in Fe-Fe2O3-Na2O-Al2O3-H2O system sequentially involves HFeO2â generation by dissolution of iron powder, HFeO2â diffusion to hematite particles, and magnetite formation on hematite particles by reaction of HFeO2â and hematite or dissolved FeO2â. Fe addition can prevent hematite particle from becoming much smaller by surface magnetization in reductive Bayer digestion compared with current industrial Bayer digestion. This work is conducive to develop a novel technology for efficiently processing high-iron diasporic bauxite.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Xiao-bin Li, Yi-lin Wang, Qiu-sheng Zhou, Tian-gui Qi, Gui-hua Liu, Zhi-hong Peng, Hong-yang Wang,