硅酸盐学报

高铁型煤系高岭土矿物学属性及其煅烧相变与活化效能

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杨红梅 ¹^,²^,³ , 吴逍 ¹^,² , 杨宜坪 ¹^,² , 苏小丽 ⁴ , 王辅亚 ¹^,² , 朱建喜 ¹^,²^,³ , 何宏平 ¹^,²^,³

硅酸盐学报 | 环境矿物材料专题—研究论文 2024,52(10): 3142-3149

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硅酸盐学报 |环境矿物材料专题—研究论文 2024 , 52 (10) : 3142 -3149

高铁型煤系高岭土矿物学属性及其煅烧相变与活化效能

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杨红梅¹^,²^,³, 吴逍¹^,², 杨宜坪¹^,², 苏小丽⁴, 王辅亚¹^,², 朱建喜¹^,²^,³, 何宏平¹^,²^,³

作者信息

^1．中国科学院矿物学与成矿学重点实验室，广东省矿物物理与材料研究开发重点实验室，中国科学院广州地球化学研究所，广州 510640

^2．中国科学院深地科学卓越创新中心，广州 510640

^3．中国科学院大学，北京 100049

^4．景德镇陶瓷大学材料科学与工程学院，江西景德镇 333403

通讯作者:

吴逍（1991—），男，博士。

作者简介:

杨红梅（1990—），女，硕士研究生。

Mineralogical Properties, Phase Transformation, and Reactivity Activation of Iron-Rich Coal-Measure Kaolin Clay During Calcination

Hongmei YANG¹^,²^,³, Xiao WU¹^,², Yiping YANG¹^,², Xiaoli SU⁴, Fuya WANG¹^,², Jianxi ZHU¹^,²^,³, Hongping HE¹^,²^,³

Affiliations

^1.CAS Key Laboratory of Mineralogy and Metallogeny, Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China

^2.CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China

^3.University of Chinese Academy of Sciences, Beijing 100049, China

^4.School of Materials Science and Engineering, Jingdezhen Ceramic University, Jingdezhen 333001, Jiangxi, China

Corresponding Author:

WU Xiao (1991-), male, Ph.D. E-mail: wuxiao@gig.ac.cn

YANG Hongmei (1990-), female, Master candidate. E-mail: yanghongmei@gig.ac.cn

出版时间: 2024-10-20 doi: 10.14062/j.issn.0454-5648.20240136

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摘要

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煤矸石含有丰富的高岭土矿物资源，对其进行资源化利用是处置这类大宗固体废弃物的重要途径，但其加工方式常受到矿物学属性的制约。以产自四川宜宾的高铁型煤系高岭土为例，采用X射线荧光光谱法、X射线粉晶衍射、扫描电子显微镜和热重-差示扫描量热法等分析测试手段研究了该煤系高岭土的化学成分、物相组成、微观形貌和热效应特征，探讨了矿物属性对热活化制备偏高岭土的影响。结果表明，宜宾煤系高岭土的主要组成矿物及其质量分数为低结晶度的高岭石（56%）、固定碳（15%）、石英（12%）和含铁矿物（11%）等；在煅烧过程中，高岭石从413 ℃开始脱除羟基，晶层在550 ℃逐渐变得无序，受其他组分影响，830 ℃时完全转变为非晶态的偏高岭石，质量损失合计26.24%；同时，黄铁矿和菱铁矿发生氧化，煅烧产物中出现含量较高的赤铁矿。此煤系高岭土经煅烧后活性显著增强，Al₂O₃溶出率在750 ℃时达到最高（68.47%，质量分数）。本工作可为高铁型煤系高岭土资源的综合利用提供矿物学依据和开发指导。

关键词

煤矸石 / 煤系高岭土 / 高岭石 / 偏高岭石 / 煅烧活化

Abstract

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Introduction

The extraction and utilization of coal inevitably lead to the generation of significant solid waste, including coal gangue. This byproduct is rich in kaolin mineral resources, and their effective utilization presents a critical strategy for the management of such a bulk solid waste, offering substantial environmental and economic benefits. The processing methodologies are often hindered by the inherent mineralogical properties of the materials. Kaolinite minerals are central to the chemical reactivity in calcined coal kaolin clay, the content and characteristics of kaolinite can vary significantly in different coal kaolin sources due to the diversity in coal-forming geological conditions. It is thus necessary to clarify the mineralogical properties of kaolinite from various sources for the innovative application of coal gangue. In this paper, a high-iron coal-series kaolin clay was analyzed. In addition, the impact of mineralogical properties on the thermal activation and preparation of calcined kaolin clay was also investigated.

Methods

A high-iron coal-series kaolin clay was obtained as a representative sample from Sichuan, China. The chemical composition, phase composition, microstructure, and thermal behavior of the high-iron coal-series kaolinproperties were determined by X-ray fluorescence spectrometry (XRF), X-ray powder crystal diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry-differential scanning calorimetry (TG-DSC).

Results and discussion

The results reveal that the chemical composition of Yibin coal-series kaolin clay is predominantly composed of SiO₂, Al₂O₃ and Fe₂O₃, with small contents of CaO, MgO, SO₃ and TiO₂, accounting for a total oxide mass of 71.84%. This coal-series kaolin clay could be categorized as high-iron coal-series kaolin clay because the content of Fe₂O₃ is 8.54%. The coal-series kaolin clay calciated exhibits a loss mass of 28.14%, which is attributed to the volatile matter and fixed carbon (15% in the mass). The principal minerals of high-iron coal-series kaolin clay along with their respective mass fractions are low-crystallinity kaolinite (56%), quartz (12%), and iron-bearing minerals such as goethite (Gth, 3%), hematite (Hem, 3%), siderite (Sd, 3%), and pyrite (Py, 2%). Furthermore, a small amounts of calcite (Cal, 3%) and anatase (Ant, 1%) also appear. The micro-morphology of the kaolinite is thin flakes or tightly stacked layers of minerals with a diameter of less than 5 μm, having a distinct laminar dissolution, and edges encrusted with small particles of calcite, quartz, anatase and other minerals.

In the calcination process, kaolinite initiates the loss of hydroxyl groups at 413 ℃, and the crystalline layers progressively become disordered at 550 ℃. It completely transforms into amorphous metakaolin at 830 ℃, accompanied by a total weight loss of 26.24%. Hematite is ultimately formed through the oxidation of pyrite and siderite, releasing volatile components such as SO₂ and CO₂. Goethite also converts to hematite, leading to an increased hematite content in the calcined product, which remains more stable at <900 ℃. In the thermal activation experiment, the kaolinite in coal gangue kaolin clay undergoes a maximal transformation into amorphous metakaolin, entailing the removal of a substantial number of hydroxyl groups and the disruption of the alumina octahedral sheet structure. This results in a shift of aluminum coordination to five-fold (Al^V), creating amorphous Al₂O₃, SiO₂, and numerous broken bonds, significantly enhancing chemical reactivity. At 750 ℃, the dissolution rate of Al₂O₃ peaks is 68.47% by mass. These results imply that the structural evolution of kaolinite at elevated temperatures is closely related to the activation process of kaolinite in Yibin coal gangue kaolin clay.

Conclusions

The results showed that heat treatment could transform Yibin coal gangue kaolin clay into calcined kaolin clay as a resource. This synthetic pozzolanic material exhibited favorable hydration properties, rendering it suitable for the fabrication of high-performance building materials, such as thermally insulated walls, thereby contributing to the conservation of resources and energy. This material could also have a potential for the partial substitution of cement in cementitious systems like concrete and geopolymers. This study could provide a mineralogical foundation and offer a developmental guidance for the comprehensive utilization of high-iron coal-series kaolin clay.

Key words

coal gangue / coal-measure kaolin / kaolinite / metakaolin / calcination activation

引用本文

杨红梅, 吴逍, 杨宜坪, 苏小丽, 王辅亚, 朱建喜, 何宏平. 高铁型煤系高岭土矿物学属性及其煅烧相变与活化效能. 硅酸盐学报, 2024 , 52 (10) : 3142 -3149 . DOI: 10.14062/j.issn.0454-5648.20240136

Hongmei YANG, Xiao WU, Yiping YANG, Xiaoli SU, Fuya WANG, Jianxi ZHU, Hongping HE. Mineralogical Properties, Phase Transformation, and Reactivity Activation of Iron-Rich Coal-Measure Kaolin Clay During Calcination[J]. Journal of the Chinese Ceramic Society, 2024 , 52 (10) : 3142 -3149 . DOI: 10.14062/j.issn.0454-5648.20240136

基金

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广东省重点领域研发计划(2020B0101370003)

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2024年第52卷第10期

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文章信息

doi: 10.14062/j.issn.0454-5648.20240136

接收时间：2024-02-22
首发时间：2026-10-22
出版时间：2024-10-20

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收稿日期：2024-02-22
修回日期：2024-03-28

基金

广东省重点领域研发计划(2020B0101370003)

作者信息

^1．中国科学院矿物学与成矿学重点实验室，广东省矿物物理与材料研究开发重点实验室，中国科学院广州地球化学研究所，广州 510640

^2．中国科学院深地科学卓越创新中心，广州 510640

^3．中国科学院大学，北京 100049

^4．景德镇陶瓷大学材料科学与工程学院，江西景德镇 333403

通讯作者:

吴逍（1991—），男，博士。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20240136

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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