Change in Microwave-Absorbing Characteristics during the Oxidation Processes of an Ilmenite Concentrate

Abstract

AbstractMicrowave-absorbing characteristics of the oxidized ilmenite concentrate were measured by the method of microwave cavity perturbation. The effects of particle size, oxidation temperature and oxidation time on the microwave-absorbing characteristics were investigated. The particle size, oxidation temperature and oxidation time have substantial impact on the microwave-absorbing characteristics of the sample and therefore the microwave heating performance during the oxidation processes of the ilmenite concentrate. Results indicated that at the same oxidation time, the microwave absorbing characteristics decreased as the oxidation temperature increased, and at a constant temperature, the microwave absorbing characteristics of the sample decreased as the oxidation time increased. The microwave absorbing characteristics of the ilmenite concentrate with 80–120 mesh particle size was stronger than that of 200 mesh particle size. The microwave absorbing characteristics of products oxidized at 900 °C for 30 min were slightly weaker than those treated at 800 °C for 30 min and 900 °C for 20 min. The sample becomes less efficient in absorbing microwave energy as the oxidation proceeds. It is therefore recommended strong microwave absorbing materials or conventional heating be applied at the late stage of oxidation to aid microwave heating.