Yan Pengze, Shen Yongqian, Du Xueyan, Chong Junkai
State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu, China.
Materials (Basel). 2020 May 7;13(9):2162. doi: 10.3390/ma13092162.
The utilization of nickel slag has attracted much attention due to its high-content of valuable elements. As a part of these efforts, this work focuses on whether magnetite crystals, obtained from nickel slag via molten oxidation, magnetic separation, and ball-milling can be used as a microwave absorber. The composition, morphology, microstructure, magnetic properties, and microwave absorption performance were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and vector network analysis (VNA). The results reveal that the magnetite crystals exhibit excellent microwave absorption properties because of the synergistic action between dielectric loss and magnetic loss. The minimum reflection loss (RL) of the particles obtained after 6 h ball-milling reaches -34.0 dB at 16.72 GHz with thickness of 5 mm. The effective frequency bandwidth (RL ≤ -10 dB) is 4.8-5.4 GHz and 15.9-17.6 GHz. Interfacial polarization of the particles could play a crucial role in improving absorbing properties because several components contained in the particles can dissipate electromagnetic wave effectively. The current study could show great potential in the preparation of magnetite crystals and utilization of nickel slag.
由于镍渣中含有高含量的有价元素，其利用已引起广泛关注。作为这些努力的一部分，本工作聚焦于通过熔融氧化、磁选和球磨从镍渣中获得的磁铁矿晶体是否可用作微波吸收剂。采用X射线衍射（XRD）、X射线光电子能谱（XPS）、场发射扫描电子显微镜（FE-SEM）、透射电子显微镜（TEM）、振动样品磁强计（VSM）和矢量网络分析（VNA）对其组成、形貌、微观结构、磁性能和微波吸收性能进行了表征。结果表明，由于介电损耗和磁损耗之间的协同作用，磁铁矿晶体表现出优异的微波吸收性能。球磨6 h后得到的颗粒在16.72 GHz、厚度为5 mm时的最小反射损耗（RL）达到-34.0 dB。有效频率带宽（RL≤-10 dB）为4.8 - 5.4 GHz和15.9 - 17.6 GHz。颗粒的界面极化在改善吸收性能方面可能起关键作用，因为颗粒中所含的几种成分能够有效地耗散电磁波。当前的研究在磁铁矿晶体的制备和镍渣的利用方面可能具有巨大潜力。
