Dielectric Properites of Iron Sulfide in Coal by Microwave Irradiation

Abstract

This study focuss on a dielectric and transformation properties of iron sulfide including pyrite, pyrrhotite, and troilite by microwave heation. The relative magnetic loss factors of pyrite at both 915 MHz and 2.45 GHz are between 0.2 and 0.4. This shows that pyrite is not a strong magnetic substance. Also, the decrease of the relative magnetic constant of pyrite is caused by the increase of electrical conductivity of sample, as indicated by the variation of permittivity. The large dielectric constant and loss factor of pyrrhotite at temperatures below 200°C suggest that this phase has good microwave absorption capability at microwave frequency. The dielectric constant and loss factor of troilite are found to be highly temperature and frequency dependent.

Microwave Treatment of Copper–Nickel Sulfide Ore for Promotion of Grinding and Flotation

“…The permittivities and permeabilities of the ore and the main sulfide minerals, including chalcopyrite, pyrite, and pyrrhotite, were measured firstly by the coaxial method using a vector network analyzer (VNA, E5071C, Agilent Technology Co., Ltd., Santa Clara, CA, USA) in the frequency range 2-4 GHz. Note that pentlandite could be intimated by pyrrhotite with similar properties and the magnetism of chalcopyrite, pyrite, and pyrrhotite would also be beneficial for microwave treatment of the ore, as reported in the literature [20,[26][27][28][29]. Also, pure gangue minerals related to those in the ore were not prepared for the same measurement because their properties have been reported in detail [8,[30][31][32].…”