ENHANCED LIBERATION OF MINERAL AND PYRITE THROUGH LOW TEMPERATURE TREATMENT OF HERRIN IL. NO. 6 COAL

Abstract

This chapter describes the enhanced liberation of mineral and pyrite through low-temperature treatment of Herrin Illinois No. 6 coal. In a study described in the chapter, a Fritsch centrifugal ball mill was used to reduce particle size and to liberate minerals from the coal matrix. Knoop microhardness testing was employed to examine brittleness of coal and an effect of cryogenic temperature on its microhardness. An automated image analyzer connected with an optical microscope was used to obtain pyrite liberation and particle size distributions for samples ground by the centrifugal ball mill. Surface artifacts of the coal were characterized using scanning electron microscopy before and after cryogenic treatments. The chapter describes the effect of temperature on the microhardness of coal is shown. Microhardness number is decreased by lowering temperature. In other words, the brittleness of coal increases with decreasing temperature treatment. It has also been found from Knoop test that microhardness is decreased with increasing exposure time at 130 K. The various grinding time was employed to examine pyrite liberation. It is seen that both increased grinding time and decreased exposure temperature result in increased pyrite liberation.