煤气化细灰理化性质及其电磁波吸收性能

Physicochemical properties and electromagnetic wave absorption performance of coal gasification fine ash

煤气化技术作为煤炭清洁利用的主要途径之一在中国得到快速发展,细灰是煤气化过程中不可避免产生的新型固体废物。国家对绿色、清洁生产和发展循环经济逐步推行,细灰的资源化利用和无害化处理技术成为实现煤气化技术环保效益和经济效益兼得的关键所在。以煤气化细灰为研究对象,对细灰进行干燥、球磨预处理得到中位径为2μm的样品,利用XRD、Raman、SEM、TEM和XPS等分析测试技术对其晶体结构、微观形貌、组成、分子构造和元素化学态进行表征,并测试了细灰电磁波吸收性能。结果表明:细灰中含有部分石墨化的碳和单质铁,具有较完整的孔隙结构,这为其作为电磁波吸收材料提供了可能性;细灰/石蜡吸波剂在较薄厚度下同时表现出较宽的有效吸收带宽和一定强度的反射损耗,当匹配厚度为1.7 mm时,该吸波剂在15.6 GHz时达到最小反射损耗值,为-17.6 dB,此时有效吸收带宽(反射损耗值≤-10 dB)达到4.2 GHz。此外,雷达散射截面模拟结果表明:该吸波涂层能有效降低完美导体基板的电磁波散射。

Coal gasification technology,one of the main ways to clean utilization of coal,has been developed rapidly in China.Coal gasification fine ash is a new type of solid waste inevitably produced in the process of coal gasification.With the implementation of green and clean production and the development of a circular economy,the resource utilization and harmless treatment technology of coal gasification fine ash have become the key to achieving both the environmental and economic benefits of coal gasification technology.Taking coal gasification fine ash as the research object,the samples with a median diameter of 2μm were prepared by drying and ball milling.The physicochemical properties of the pre-treated coal gasification fine ash were characterized by XRD,Raman,SEM,TEM,and XPS,and the crystal structure,micromorphology,composition,molecular structure,and chemical state of the elements of the coal gasification fine ash were analyzed.Moreover,the electromagnetic wave absorption performance was tested.The results show that the fine ash contains some graphitized carbon and zero-valent iron,and has a relatively complete pore structure,which provides a possibility for it to be used as an electromagnetic wave-absorbing material.The absorbers exhibit the minimum reflection loss(RLmin)of-17.6 dB at 1.7 mm,and broad absorption bandwidth(RL≤-10 dB)of 4.2 GHz.In addition,the radar cross-section simulation results show that the fine ash/paraffin coating can effectively reduce the electromagnetic wave scattering of the perfect conductor substrate.