溶剂萃取下构造煤的XRD结构演化特征

煤是一种短程有序、长程无序，且随着煤化程度的增加有序性增强、具有微晶或类晶态结构的沉积有机岩。在成煤过程中，地质构造的破坏作用使得煤发生不同程度的变形变质，引起煤的化学组成、微观结构发生变化，形成了不同煤体结构的构造煤。为了揭示构造破坏作用下，煤的微晶结构的变化特征，采用有机溶剂萃取的方法，对不同煤体结构的贫煤、气煤样进行了萃取。借助于X射线衍射(XRD)测试结果，探讨了煤样萃取前后的微晶结构的变化规律。研究发现：在溶剂萃取作用下，构造煤的萃取率所呈现的规律性变化并不因溶剂的种类、煤级的变化而改变，表现为溶剂萃取率均随着煤体破坏程度的增强而增大。室温条件下，溶剂的萃取并不足以改变高、低阶煤的微晶结构参数的对比关系，溶剂萃取前后均表现为贫煤的芳香层间距d₀₀₂小于气煤，堆砌度L_c和芳香层数N大于气煤。进一步研究发现构造的破坏作用下，萃取后d₀₀₂逐渐减小，L_c增大，而由于煤级的影响，以及溶剂的种类和渗入强弱不同，延展度L_a并没有表现出明显的规律性。

XRD Structure Evolution Characteristics of Tectonic Coal Under Solvent Extraction

Coal is a kind of sedimentary organic rock with the feature of microcrystalline and crystalloid structure in long-range disorderly and short-range orderly.As coalfication degree increases,coal structure grows more regular.In the coal-forming process,coal body has deformed in different degree due to the destruction of geological structures,and thus the chemical compo-sition and microcrystalline structure of coal have been changed,which have made tectonic coal with different coal body structure formed.In order to study on change law of the microcrystalline structure of coal under geologic structure,the paper is exampled by two kinds of coal with different rank,that is gas coal and lean coal,and investigated on the differences in microcrystalline structure for coal samples with different deformed degree before and after solvent extraction.By means of X-ray diffraction (XRD),the microcrystalline structures of coal samples and their residues were measured.The results show that the solvent ex-traction rate appear a post relationship with the degree of coal body structure,and the contrasts of the extraction between differ-ent deformed coal samples do not alter with the change of solvent species and coal ranks.Meanwhile,under room temperature conditions,the solvent extraction is not enough to alter the contrast relationships of microcrystalline structure parameters be-tween high and low rank coal .The value of aromatic lamellae spacing (d 002 )of lean coal is less than gas coal,and stck high (L c ) and layer numbers (N )is more than gas coal.Further study indicates that the value of d 002 decreases and L c increases under the tectonic damaging effects.But the value of the diameter (L a )does not show obvious regularity at the influence of coal ranks,sol-vent species and infiltration degree.