煤系针状焦微晶结构的XRD与Raman分峰拟合定量研究

采用XRD和Raman光谱分析技术,结合分峰拟合的数学方法,对不同生产厂家的三种煤系针状焦Coke-N,Coke-H,Coke-P进行了研究。由XRD分析结果计算出了三种针状焦的石墨化度、晶体结构类型以及晶粒尺寸(La和Lc),通过对XRD的分峰拟合处理,得出了三种针状焦中趋于规整结构的碳微晶含量(Ig)。通过对样品的XRD分析可知,Coke-N和Coke-P的石墨化程度及Lc相接近,并且明显大于Coke-H;La之间的关系为:Coke-NCoke-PCoke-H。通过Raman光谱结合分峰拟合的数学方法对样品进行了定量分析。研究结果表明,三种针状焦在拉曼位移1 000~2 000cm-1处有5个一阶谱拟合峰(G,D1,D2,D3,D4)。对样品的拉曼一阶谱拟合后所得出的每个拟合峰面积进行计算,可以用来定量分析三种针状焦中碳微晶结构的分布情况。由I_G/I_(All),I_(D1)/I_G,I_(D2)/I_G,I_(D3)/I_G,I_(D4)/I_G的计算可知,Coke-N和Coke-P的微晶结构比Coke-H的微晶结构更规整。在Coke-N中理想石墨碳微晶所占比例为0.33,而Coke-H和Coke-P分别为0.086和0.311。另外,Coke-H在三个样品中的无定形碳比例明显大于另外两个样品。Raman光谱分析结果与XRD的分析结果相吻合。由此可以看出,采用XRD和拉曼光谱分析技术可以从微观层面判定宏观质量不同的煤系针状焦差异的实质。

Quantitative Study of the Microcrystal Structure on Coal Based on Needle Coke with Curve-Fitted of XRD and Raman Spectrum

Three kinds of needle coke (numbered as Coke-N,Coke-H and Coke-P) from different sources were studied with X-ray diffraction (XRD),Raman spectrum and curve-fitting analysis.The graphitization degree,crystal structure types and crystal size (La and Lc) of these three needle cokes were calculated with XRD.According to the curve-fitted analysis of XRD,the content of ordered crystallite structure (Ig) on the three needle coke samples was obtained.The graphitization degree of Coke-N and Coke-P were similar,which were obviously greater than that of Coke-H;the relationship of La between these needle cokes are:COoke-N＞Coke-P＞Coke-H.Raman spectrum coupled with curve-fitted method was used for quantitative analysis of samples.With Raman spectrum and math method,the cokes at zone of 1 000～2 000 cm-1 had been analyzed with curve-fitted method.This first-order spectrum had been curve-fitted to five peaks (G,D1,D2,D3,D4).The area of each fitted curve was used to calculate the distribution of carbon crystalline.The parameters of IG/IAl1,ID1/IG,ID2/IG,ID3/IG and ID4/IG had shown that,the crystallite structure of Coke-N and Coke-P were more order than Coke-H.The ratio of ideal microcrystalline graphite carbon in Coke-N was 0.33,but the parameters of Coke-H and Coke-P were 0.086 and 0.311 respectively.What's more,the ratio of amorphous carbon in Coke-H was obviously higher than other that of two samples.The results were corresponding to that of XRD analysis.Therefore,XRD and Raman spectrum analysis was an important method to judge the essence of coal-based needle cokes with different macro quality on the microcosmic level.