废轮胎回转窑中试热解炭中碳元素化学形态

应用X射线光电子能谱（XPS）对废轮胎回转窑中试热解炭（PCB）中C元素的化学形态进行分析.荷电效应及背景校正后，分别应用“非对称性Gaussian-Lorentzian线性和函数”与“Gaussian函数”对非对称与对称峰进行拟合.结果发现，热解温度≥500 ℃时，热解充分，热解炭本体中C元素的化学形态类似商用炭黑（CCB）N660，而热解炭表面吸附沉积物中C元素的化学形态不同于本体，随热解温度升高，表面吸附物中类石墨质C有所增加;450℃时，热解不充分，热解炭本体中类石墨质C含量少，表面吸附物少;热解炭按粒径存在一定的分布，热解炭颗粒越小，石墨质C含量越低;热解炭表面吸附、沉积物厚度的近似数量级为0.2 mm，热解炭本体中C元素的化学形态并未受到表面吸附、沉积层太大的影响.

Chemical structure of C in carbon blacks from pyrolysis of used tires in pilot-scale rotary kiln

The chemical structure of C in pyrolytic carbon black(PCB) from the pyrolysis of used tires in a pilot-scale rotary kiln was analyzed by X-ray photoelectron spectroscopy(XPS).The surface charging and background were corrected and the asymmetrical and symmetrical peaks were fitted by “asymmetrical Gaussian-Lorentzian sum function” and “Gaussian function”, respectively. It was found that when pyrolysis was complete at a temperature above 500℃,the chemical structure of C in the bulk of PCB was similar to commercial carbon black(CCB) N660, but different from the PCB surface layer containing absorbates and deposits.At a higher pyrolysis temperature, the content of graphitic C in the surface layer increased. When pyrolysis was not complete at 450℃,the content of graphitic C in the bulk was low and the surface layer was thinner.The PCB was sieved, and the smaller the PCB particle diameter, the lower the content of graphitic C. The thickness of the PCB surface layer was about 0.2 mm and the chemical structure of C in the bulk of PCB was not affected by the surface layer.