Enhanced alumina extraction from kaolin by thermochemical activation using charcoal

IF 1.1 4区地球科学 Q4 CHEMISTRY, PHYSICAL

Clay Minerals Pub Date : 2021-12-01 DOI:10.1180/clm.2022.7

Amr B. ElDeeb, V. Brichkin, M. Bertau, M. Awad, Yulia Savinova

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引用次数: 1

Abstract

Abstract The present work aims to increase the alumina percentage recovery (APR) extracted from kaolin via the addition of 0.5–4.0 wt.% charcoal as a thermochemical fluxing agent in the lime-sintering process at 1260–1360°C. The transformation, microstructural and microtextural changes and self-disintegration performance were characterized using thermogravimetric analysis and differential scanning calorimetry, X-ray diffraction/X-ray fluorescence, scanning electron microscopy coupled with energy-dispersive spectroscopy and laser diffraction particle-size distribution analysis. The optimum enhancement of APR, from 77.7% to 87.40%, was obtained by sintering at 1360°C with the addition of 1.5% charcoal. With further increase of the charcoal content to 4%, the APR reduced to 75.6%. Combustion of ≤1.5% charcoal provided additional heat that amorphized the crystalline calcium aluminate into highly leachable amorphous phases with improved self-disintegration efficiency. Sintering at temperatures of >1360°C or with charcoal contents >4% led to mullite crystallization and decreased alumina leachability, thereby reducing the APR. Charcoal is a cost-effective and energy-efficient activator to increase the APR extracted from kaolin.

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炭热化学活化法从高岭土中萃取氧化铝

摘要本研究旨在通过添加0.5-4.0 wt.%的木炭作为热化学助熔剂，在1260-1360℃的石灰烧结工艺中提高从高岭土中提取的氧化铝的回收率(APR)。采用热重分析、差示扫描量热法、x射线衍射/ x射线荧光、扫描电镜-能量色散光谱和激光衍射粒度分布分析等方法对其相变、显微组织和微织构变化及自崩解性能进行了表征。在1360℃下烧结，添加1.5%的木炭，APR的最佳提高幅度为77.7% ~ 87.40%。随着炭含量的增加至4%，APR降至75.6%。燃烧≤1.5%的木炭提供了额外的热量，使结晶铝酸钙非晶化成高度可浸出的非晶相，提高了自崩解效率。烧结温度为> ~ 1360℃或木炭含量为> ~ 4%时，莫来石结晶，氧化铝浸出率降低，从而降低了APR。木炭是一种经济高效的活化剂，可以提高高岭土提取的APR。

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来源期刊

Clay Minerals 地学-矿物学

CiteScore

3.00

自引率

20.00%

发文量

审稿时长

6 months

期刊介绍： Clay Minerals is an international journal of mineral sciences, published four times a year, including research papers about clays, clay minerals and related materials, natural or synthetic. The journal includes papers on Earth processes soil science, geology/mineralogy, chemistry/material science, colloid/surface science, applied science and technology and health/ environment topics. The journal has an international editorial board with members from fifteen countries.