Research on dielectric characterization of laterite ores under microwave radiation

Abstract

Dielectric property of laterite ores plays a key role in the determination of its treatment effect by microwave. However, till date, to our knowledge, there is no article reported on the dielectric property of laterite ores up to the nickel–iron alloy extraction temperature of around 1200 °C, which impedes the efficient application of microwave power in the nickel–iron alloy extraction. This paper, in view of this, aims to provide the dielectric property variation of laterite ores treated by microwave radiation from room temperature up to 1250 °C. A custom-designed ridge waveguide-based system is applied to perform the measurement. To verify the reliability of the measured results and explain the experimental phenomenon, X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis are employed to conduct a thorough understanding on the variation of dielectric properties of laterite ores under different temperatures. The measured data are qualitatively verified by its temperature change tendency, SEM and XRD analysis. This work may be helpful to avoid thermal runaway, design more efficient microwave devices and optimize the existing production line of microwave treating laterite ores.