Dielectric properties and thermal behavior of electrolytic manganese anode mud in microwave field

Exploring the dielectric properties of a material can provide guidance for applications of microwave technology to the material. In this work, dielectric properties and thermal behavior of manganese anode mud and pure MnO₂, CaSO₄ and PbSO₄ components were systematically investigated. Results indicated that manganese anode mud showed excellent responsiveness to microwaves, with ε_r' value of 17.971 (F/M) at room temperature and a maximum value of 20.816 (F/M) at 150 °C, rendering it took only 5.5 min for manganese anode mud to be heated from room temperature to 1000 °C. The dielectric properties of manganese anode mud were related to its thermal behavior, mainly affected by MnO₂ component. Moreover, the heating process of manganese anode mud was divided into four stages identified by temperatures: less than 200 °C, 200 °C-700 °C, 700 °C-900 °C, greater than 900 °C, corresponding to the five stages of thermal behavior: the removal of absorption water and combined water, the decomposition reaction of Pb₂Mn₈O₁₆, and the deoxidation reactions of PbO₂, MnO₂ and Mn₃O₄. The work highlights the feasibility of processing manganese anode mud by microwave heating.