Selective magnetic enhancement of pyrite in coal by dielectric heating at 27 and 2450 MHZ

Abstract

The objective of this project is to improve the magnetic separation of coal and pyrite by enhancing the magnetic susceptibility of pyrite in run‐of‐mine (ROM) coal through the use of selective pretreatments such as dielectric heating and induction heating. Separation of pyrite from coal would be facilitated by changing a portion of each pyrite particle to a more magnetic form. The selective magnetic enhancement of pyrite in coal by dielectric heating was investigated fundamentally and experimentally. Fundamental treatment consisted by the measurement of the dielectric properties, at frequencies ranging from 1 HMz to 11.7 GHz, of a selection of coals and their pyritic fractions. These values were then used to calculate the theoretical heating that would be produced in these materials and their mixtures. The experimental treatment involved heating fractions and their mixtures at 27 and 2,450 MHz. Results showed limited agreement between theoretical and experimental heating and that it is possible to selectively heat pyrite in coal. Preliminary data indicate an increase in the apparent mass susceptibility of dielectically heated pyrite samples that is roughly proportional to the time and power of pretreatment. Magnetic separation tests are being started.