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

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单位School of Minerals Processing & Bioengineering, Central South University, Changsha 410083, China;School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China
来源武汉理工大学学报(材料科学版)(英文版)
出版年2014
期号第1期
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.
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