Comparison of Chemical Reactivity of Bauxite-tailings Pre-and Post-calcinations and Whitening Bauxite-tailing  

作　　者：卢清华 LIU Kun CHEN Baizhen 胡岳华 

机构地区：[1]School of Minerals Processing & Bioengineering, Central South University [2]School of Metallurgical Science and Engineering, Central South University

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2014年第1期29-34,共6页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the Postdoctoral Fund of Central South University(No.74142000032)

摘　　要：Bauxite-tailings is aluminosilicate wastes and is used in polymer as fillers. But its intrinsic low-whiteness has limited its large-scale application in polymeric materials. Conventional methods for whitening bauxite-tailings were ineffective. A new method, which involved reactions with phosphoric acid and calcinations, was proposed to whiten bauxite-railings. Two process routes were employed to whiten bauxite- tailings, which were pre- and post-reaction calcination. While the process of pre-reaction calcination was able to achieve a whiteness of 87% from bauxite-railings, it required high-energy post-treatment processes such as washing, milling and drying. The process of post-reaction calcination, on the other hand, resulted in an increase in whiteness of bauxite-tailings from 19% to 73%. This was achieved using 4.5% of added phosphorous, 40% acid concentration, reaction time of 2.5 hours and a calcination temperature of 600 ℃ The resultant did not require any further processing, and was therefore industrially feasible. The whitened tailings consisted of corundum, anatase, and quartz. When compared to calcined tailings, whitened tailings possessed a higher content of amorphous material, the disappearance of red iron minerals, and the emergence of a new phase of A1PO4.Bauxite-tailings is aluminosilicate wastes and is used in polymer as fillers. But its intrinsic low-whiteness has limited its large-scale application in polymeric materials. Conventional methods for whitening bauxite-tailings were ineffective. A new method, which involved reactions with phosphoric acid and calcinations, was proposed to whiten bauxite-railings. Two process routes were employed to whiten bauxite- tailings, which were pre- and post-reaction calcination. While the process of pre-reaction calcination was able to achieve a whiteness of 87% from bauxite-railings, it required high-energy post-treatment processes such as washing, milling and drying. The process of post-reaction calcination, on the other hand, resulted in an increase in whiteness of bauxite-tailings from 19% to 73%. This was achieved using 4.5% of added phosphorous, 40% acid concentration, reaction time of 2.5 hours and a calcination temperature of 600 ℃ The resultant did not require any further processing, and was therefore industrially feasible. The whitened tailings consisted of corundum, anatase, and quartz. When compared to calcined tailings, whitened tailings possessed a higher content of amorphous material, the disappearance of red iron minerals, and the emergence of a new phase of A1PO4.

关 键 词：WHITENESS bauxite tailings fillers 

分 类 号：X751[环境科学与工程—环境工程]