Study on Microwave Heating Order and Electromagnetic Characteristics of Copper and Gold Ores

Microwave heating and grinding experiments were conducted on samples of Hongtoushan copper ore and Dandong gold ore with different particle sizes and forms. The differences between the heating effects observed were then investigated using the electromagnetic characteristics of the bulk and powdered ore samples. The results show that the bulk copper ore experiences a high shielding effect as the microwaves are strongly reflected. The dielectric constant and reflection from a powdered sample are significantly weaker. Microwaves of frequency 2.45 GHz produce an insignificant heating and grinding effect in a cylindrical sample of Hongtoushan copper ore; the heating and grinding effect using a particulate sample is significantly better. In contrast, the heating and grinding effect obtained using a cylindrical sample of Dandong gold ore is better than that obtained using a particulate sample. The reasonable use of microwave heating to process ore is also discussed. Hongtoushan copper ore is suitable for microwave treatment after fine crushing. Dandong gold ore is suitable for microwave treatment before fine crushing. In the latter case, the application of microwaves could be moved forward to the mining process stage before carrying out the other procedures further downstream.