粒度对硼铁矿介电特性及微波加热特征的影响

Effect of Particle Size on Dielectric Properties and Microwave Heating Characteristics of Ludwigite

采用谐振腔微扰法测定了不同粒度的硼铁矿在频率为2. 45 GHz和温度为20~800℃的介电特性,并测定其在微波场下的升温特征.结果表明:随着矿样粒度的减小,填充层空隙率降低,其介电特性增强,微波场中矿样的升温速率加快.当温度高于200℃时,矿样发生热分解产生大量微空隙而增大了空隙率,矿样的介电特性呈下降趋势,使得微波加热过程中矿样的升温速率降低.粒度对硼铁矿介电特性和升温特征的影响研究为微波在冶金领域中的应用及节约能耗提供理论依据.

The cavity perturbation method was used to measure the dielectric properties of ludwigite of different particle sizes at the frequency of 2.45 GHz with the temperature ranging from 20 to 800℃,and heating characteristics under a microwave field were also measured.The results showed that with the decrease of particle size,the filling layer porosity of the ore sample decreases,while the dielectric properties and the heating rate increase.When the temperature is higher than 200℃,the thermal decomposition can generate a large number of micro-voids which increases the porosity,and the dielectric properties tend to be decreased,resulting in a reduce of heating rate during microwave heating.The effect of particle size on the dielectric properties and temperature rising characteristics of ludwigite provides a theoretical basis for the application of microwave in the fields of metallurgy and saving energy consumption.