【摘要】 随着图像识别和模式识别技术的发展，基于射线的干法分选得到了广泛的发展和应用，特别是在干旱地区。利用X射线透射技术分选煤和矸石时，煤和矸石的识别基于两者对X射线吸收的差异。以往的研究主要关注原子序数和密度，只能识别出密度差较大的煤和矸石，无法很好地解释识别的深层机制。同时，晶体结构的演变与X射线吸收之间的关系尚未得到研究。通过TG/DSC、XRD、FTIR等实验方法检测了高岭石在退火过程中的变化。利用Materials Studio模拟高岭石晶体结构逐渐向无序转变过程中可能出现的晶体结构。用FEFF9对模拟结构进行了X射线吸收光谱计算。结果表明，X射线吸收精细结构光谱可以反映高岭石中硅元素局部环境的有价值信息。进一步研究发现，随着高岭石畸变的增加，XANES的吸收峰从1846.7 eV到1845.1 eV有轻微的位移，强度突变从1.76增加到3.86。通过FEFF9计算验证了高岭石晶体在退火过程中的变形机理，为煤矸石分选中不同变形程度高岭石的识别提供了理论支持。更多还原

【Abstract】 With the development of image recognition and pattern recognition technology, dry sorting based on ray has been widely developed and applied, especially in arid areas. When sorting coal and gangue by X-ray transmission technology, recognition of coal and gangue are based on the differences of X-ray absorption. Previous works have paid much attention to the atomic number and density. Only coal and gangue with large density difference can be identified, and the deep mechanism of identification cannot be well explained. At the same time the relationship between the evolution of crystallographic structure and X-ray absorption has not been researched. Experimental methods including TG/DSC, XRD and FTIR were used to detect the change of kaolinite during annealing. Materials Studio was used to simulate the possible crystal structure during the gradual disordering of kaolinite crystal structure. The simulated structures were calculated by FEFF9 for X-ray absorption spectroscopy. The results show that X-ray absorption fine structure spectroscopy can represent valuable information about the Si local environment in kaolinite. Further investigation determined that the XANES absorption peak shifts slightly from 1846.7 eV to 1845.1 eV and the intensity mutation increases from 1.76 to 3.86 with the increase of kaolinite distortion in stages. This work proves the study on the distortion mechanism of kaolinite crystal during annealing with FEFF9 calculation which provide theoretical support for identifying kaolinite with different distortion degrees in coal gangue separation.更多还原