Dielectric characterizations and heating behavior of siderite in microwave field

Microwave absorption capabilities of siderite, Fe₃O₄ and Fe₂O₃ were investigated by measuring the dielectric characterization (dielectric constant, loss factor and loss tangent) from room temperature to 900 °C using the microwave cylindrical resonant cavity technique at 2450 MHz. There was little change in the microwave absorption capabilities of siderite before 600 °C. As the temperature increasing, the microwave absorption capabilities of siderite increased sharply due to the generation of Fe₃O₄. However, the microwave absorption capabilities of siderite decreased when temperature higher than 900 °C, which was attributed to the formation of Fe₂O₃ by the oxidation of Fe₃O₄. The microwave heating behavior of siderite was studied and the result showed that the heating rate of siderite became slower when temperature higher than 550 °C, this was because amount of decomposition reaction of siderite occurred in this stage which consuming large amounts of heat.