煤矸石资源化利用过程中微量元素的环境地球化学研究

摘要

煤矸石是煤炭开采过程中的伴生矿物，是煤矿活动的主要固体废物，也是我国主要的工业固体废物。由于具有低热值和高粘土等属性，煤矸石被广泛用于发电、复垦、建筑材料生产等。在煤矸石各种资源化利用过程中，煤矸石中的有害物质会向周边环境释放，对周边土壤、水体、动植物和人类造成潜在影响。因此，研究煤矸石利用过程中微量元素的环境地球化学特征具有必要性和迫切性。
　　本研究以淮南矿区煤矸石为研究对象，通过室内模拟和现场样品采集相结合的方法，利用X射线荧光光谱、X射线衍射、扫描电镜能谱、光学显微镜、热重分析、傅里叶红外光谱、电感耦合等离子体原子发射光谱和质谱等技术手段分析和测定样品的化学组成、矿物组成、微观形貌、精细结构和元素含量，结合煤化学、矿物学、元素地球化学和环境化学等交叉学科理论，对煤矸石资源化利用过程中微量元素的迁移行为、分布模式和环境效应等科学问题进行了研究。通过研究，分析了淮南矿区煤矸石的化学组成、矿物组成和微量元素特征，揭示了淮南矿物微量元素的分布规律和赋存形态;利用室内层温燃烧试验，探讨了煤矸石矿物结构、微观形貌、晶相结构和微量元素与燃烧温度的关系，解析了微量元素在煤矸石燃烧过程中的迁移行为;建立了煤矸石利用过程中微量元素的分配模式，结合质量守恒原理和元素的挥发特性，将淮南煤矸石微量元素分为易挥发性元素(As、Cd、Cu、Pb、Se和Sn)、挥发性元素(Bi、Ni和Zn)和难挥发性元素(Cr、Co、Mn和V);基于相关性分析和化学逐级提取实验，揭示了微量元素赋存形态在煤矸石燃烧过程中的转化规律;讨论了煤矸石与生物质燃烧过程中的共燃特性、动力学特征和微量元素行为，确定了煤矸石与生物质共燃的最优配比;评价了煤矸石燃烧对周边环境的影响，计算了中国制砖过程中微量元素的排放清单;丰富了煤矸石资源化利用过程中微量元素的环境地球化学理论体系，为煤矸石的深度利用和环境保护提供了理论参考和技术支持。

目录

声明

ABSTRACT

摘要

List of contents

Chapter 1-Introduction

1．1．The environmental impacts of coal gangue

1．1．1．The importance of coal

1．1．2．The production of coal gangue

1．1．3．The environmental impacts of coal gangue

1．2．The association and adverse effects of trace elements in coal gangue

1．2．1．Trace elements in coal gangue

1．2．2．The modes of occurrence of traee elements in coal gangue

1．2．3．The potential adverse effects of trace elements in coal gangue

1．3．Transformation and partitioning behavior of trace elements during the utilization of coal gangue

1．3．1．The utilization of coal gangue

1．3．2．Partitioning behavior of trace elements during the utilization of coal gangue

1．4．Overall objectives

Chapter 2-The concentrations and modes of occurrence of trace elements in coal gangue

2．1．Introduction

2．2．Experimental

2．2．1 Samples collection

2．2．2．Petrographic analysis

2．2．3．Elemental analysis

2．2．4．Sequential extraction procedure

2．3．Results and discussion

2．3．1．The physico-chemical properties of coal gangue

2．3．2．Modes of occurrence of trace elements

2．4．Conclusions

Chapter 3-Transformation behavior of mineral compositions and trace elements during coal gangue combustion

3．1．Introduction

3．2．Experimental

3．2．1．Coal gangue sample

3．2．2．Thermogravimetric and differential thermal analysis

3．2．3．Combustion procedure

3．2．4．Morphological and mineralogical analysis

3．2．5．FTIR spectroscopy analysis

3．2．6．Trace elements analysis

3．3．Results and discussion

3．3．1．TGA，DTA and DSC characterization

3．3．2．Morphological and mineralogical characterization

3．3．3．Phase transition characterization

3．3．4．Geochemical characterization of trace elements

3．4．Conclusion

Chapter 4-Partitioning and transformation behavior of trace elements during circulated fluidized bed combustion of coal gangue

4．1．Introduction

4．2．Materials and methods

4．2．1 Plant description

4．2．2 Sample collection

4．2．3 Mineral analysis

4．2．4 Chemical analysis

4．2．5 Sequential chemical extraction procedure

4．3．Results and discussion

4．3．1．The mineralogical characterization

4．3．2．Relative distribution of trace elements in the power plant

4．3．3．The transformation behavior of trace elements in the power plant

4．4．Conclusions

Chapter 5-Thermochemical and trace elements behavior of coal gangue，agricultural biomass and their blends during co-combustion

5．1．Introduction

5．2．Materials and methods

5．2．1．Sampling

5．2．2．Thermogravimetric analysis

5．2．3．Trace element analysis

5．3．Results and discussion

5．3．1．The properties of coal gangue and biomass

5．3．2．Thermal behaviors of coal gangue，biomass and their blends

5．3．3．Effect of heating rates on thermal characteristics

5．3．4．Kinetic parameters of coal gangue，biomass and their blends

5．3．5．Effect of co-combustion on current combustion application

5．4．Conclusions

Chapter 6-The environmental geochemistry of trace elements and natural radionuclides in a coal gangue brick-making plant

6．1．Introduction

6．2．Materials and methods

6．2．1．Plant description

6．2．2．Sample collection

6．2．3．Radioactivity analysis

6．2．4．Chemical analysis

6．3．Results and discussion

6．3．1．The properties of coal gangue

6．3．2．Partition behavior of trace elements

6．3．3．Behavior of natural radionuclides

6．3．4．Gaseous emission of trace elements

6．3．5．Distribution behavior of the trace elements in soil and crops around the brick-making plant

6．4．Conclusions

Chapter 7-Atmospheric emissions of toxic elements(As，Cd，Hg，and Pb)from brick-making plants in China

7．1．Introduction

7．2．Methodology

7．2．1．Raw materials consumption

7．2．2．Provincial averaged concentrations of toxic elements in raw materials

7．2．3．Emission factors of toxic elements

7．3．Results and discussion

7．3．1．Emission behavior of toxic elements in brick-making processes

7．3．2．Temporal and spatial characterizations of toxic elements emissions from brick-making processes

7．3．3．Uncertainties

7．3．4．Potential countermeasures

7．4．Conclusions

Chapter 8-主要成果与创新点

8．1 主要成果

8．2 创新点

References

Appendix

Acknowledgements

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