Comparison of radar absorbing properties of sintered zinc industry wastes in the 2–18 GHz frequency range

Abstract

This study investigates the conversion of zinc industry wastes zinc leach residue (ZLR), brass chip waste (BW), and brass flue dust (BFD) into radar-absorbing materials (RAM) for 2–18 GHz applications. The wastes were sintered at 700 °C/3 h and characterized for their physical (grains size and porosity), chemical (XRF), mineralogical (XRD), and electromagnetic (EM) properties. Electrical characterizations were performed with Vector Network Analyzer (VNA) and waveguides. BW exhibited the highest dielectric (tan δε) and magnetic (tan δμ) loss tangents, achieving a minimum reflection loss (RLmin) of − 35.2 dB and an effective absorption bandwidth (EAB) of 5.6 GHz at an optimal thickness of 2.5 mm. BFD and ZLR showed moderate RLmin values of − 28.7 dB and − 22.1 dB, respectively, with corresponding EABs of 4.2 GHz and 3.5 GHz. The results demonstrate that BW offers superior microwave absorption, while all three wastes can be effectively repurposed into cost-efficient RAM structures. This approach not only valorises hazardous industrial byproducts but also contributes to sustainable material development and circular economy practices in the metals industry.