Search

Dielectric properties of zinc oxide leach residues from a smelter in Yunnan province, China and having a moisture content of 28.97% as well as samples prepared separately with moisture contents of 10, 15, 20 and 25% are measured between 20 and 110 degrees C using cylindrical cavity perturbation equipment. The 3D response surface plots are presented for the effects of temperature and moisture content on the dielectric constant, loss factor and penetration depth of the microwave energy in the zinc oxide leach residues. The 3D plots indicate that, under the interaction of temperature and moisture content, the dielectric constant and the loss factor decrease while the penetration depth of the microwave energy increases during the microwave-drying process. Taking into account the variations of penetration depth of the microwave energy with temperature and moisture content, the bed depth should fall in the range 26-50 mm. Three models using regression methods and analysis of variance to accurately predict the dielectric properties and the penetration depth of the microwave energy in zinc oxide leach residues are described., Dielectric properties of zinc oxide leach residues from a smelter in Yunnan province, China and having a moisture content of 28.97% as well as samples prepared separately with moisture contents of 10, 15, 20 and 25% are measured between 20 and 110 degrees C using cylindrical cavity perturbation equipment. The 3D response surface plots are presented for the effects of temperature and moisture content on the dielectric constant, loss factor and penetration depth of the microwave energy in the zinc oxide leach residues. The 3D plots indicate that, under the interaction of temperature and moisture content, the dielectric constant and the loss factor decrease while the penetration depth of the microwave energy increases during the microwave-drying process. Taking into account the variations of penetration depth of the microwave energy with temperature and moisture content, the bed depth should fall in the range 26-50 mm. Three models using regression methods and analysis of variance to accurately predict the dielectric properties and the penetration depth of the microwave energy in zinc oxide leach residues are described.

Cylindrical cavity perturbation method was used to measure complex permittivity of zinc oxide leach residues (ZOLR) at a frequency of 2.45 GHz. The results indicate that both dielectric constant and loss factor of ZOLR increased with an increase in temperature and moisture content. The research of ZOLR’s microwave absorption properties were performed based on reflection loss (RL) theory. Microwave absorption peak of ZOLR moves towards higher material thickness with decreasing moisture content. However, microwave absorption peak of ZOLR moves towards smaller material thickness with increasing temperature. RL of ZOLR sensitively depends on its material thickness. In order to keep microwave absorption properties of ZOLR greater than 90% in the process of microwave drying, then 10 mm, 40 mm, and 50 mm should be selected as the optimum material thickness., Cylindrical cavity perturbation method was used to measure complex permittivity of zinc oxide leach residues (ZOLR) at a frequency of 2.45 GHz. The results indicate that both dielectric constant and loss factor of ZOLR increased with an increase in temperature and moisture content. The research of ZOLR’s microwave absorption properties were performed based on reflection loss (RL) theory. Microwave absorption peak of ZOLR moves towards higher material thickness with decreasing moisture content. However, microwave absorption peak of ZOLR moves towards smaller material thickness with increasing temperature. RL of ZOLR sensitively depends on its material thickness. In order to keep microwave absorption properties of ZOLR greater than 90% in the process of microwave drying, then 10 mm, 40 mm, and 50 mm should be selected as the optimum material thickness.