Comparison of the effects of Ti-and Si-containing minerals on goethite transformation in the Bayer digestion of goethitic bauxite  

作　　者：Guotao Zhou Yilin Wang Tiangui Qi Qiusheng Zhou Guihua Liu Zhihong Peng Xiaobin Li 

机构地区：[1]School of Metallurgy and Environment,Central South University,Changsha 410083,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2023年第9期1705-1715,共11页矿物冶金与材料学报（英文版）

基　　金：the financial support provided by the National Natural Science Foundation of China (No.52104353);the National Key Research and Development Program of China (No.2022YFC3900900)。

摘　　要：Goethitic bauxite is a widely used raw material in the alumina industry.It is an essential prerequisite to clarify the effect of Ti-and Si-containing minerals on goethite transformation in the Bayer digestion process,which could efficiently utilize the Fe-and Al-containing minerals present in goethitic bauxite.In this work,the interactions between anatase or kaolinite with goethite during various Bayer digestion processes were investigated using X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),transmission electron microscopy (TEM),and scanning electron microscopy (SEM).The results showed that anatase and kaolinite hindered the transformation of goethite.Anatase exerted more significant effects than kaolinite due to the dense sodium titanate layer on the goethite surface after reacting with the sodium aluminate solution.Adding the reductant hydrazine hydrate could eliminate the retarding effect by inducing the transformation of goethite into magnetite.In this process,titanium was embedded into the magnetite lattice to form Ti-containing magnetite.Furthermore,the weakening of the interaction between magnetite and sodium aluminosilicate hydrate reduced the influence of kaolinite.As a validation of the above results,the reductive Bayer method resulted in the transformation of goethite into goethitic bauxite with 98.87% relative alumina digestion rate.The obtained red mud with 72.99wt% Fe2O3could be further utilized in the steel industry.This work provides a clear understanding of the transformative effects of Ti-and Si-containing minerals on iron mineral transformation and aids the comprehensive use of iron and aluminum in goethitic bauxite subjected to the reductive Bayer method.

关 键 词：GOETHITE magnetite KAOLINITE ANATASE Bayer digestion 

分 类 号：TF82[冶金工程—有色金属冶金]