Comparison of the Microwave Absorption Characteristics of Hematite, Magnetite and Pyrite

We provide an understanding of the microwave absorption characteristics of hematite, magnetite and pyrite by measuring and comparing the microwave heating rate, dielectric and magnetic properties and the absorbed microwave energy. The three methods have their own advantages and disadvantages, and supplement each other. Magnetite showed the strongest microwave absorption and rapid heating rate because of its dielectric and magnetic losses. Dielectric properties and calorimetry indicate that two pyrite samples had different microwave absorption characteristics, but a similar heating rate. Three types of hematite had a significant difference in interaction with the microwave. The heating rate of one of the hematite samples was most rapid and the sample had a higher dielectric loss factor. The ability of these minerals to absorb microwaves was maintained at a certain level when the microwave power and microwave heating time increased. For microwave-sensitive materials, the amount of absorbed microwave energy increased significantly with their mass.