Microwave heating of coal for enhanced magnetic removal of pyrite

Abstract Amenability of Askale coal to desulfurization by magnetic separation following microwave heating was investigated. The coal was subjected to magnetic separation at 2 T following the treatment in a microwave oven at 850-W power and 2.45-GHz frequency. The increase in magnetic property by microwave heating at 850 W and 2.45 GHz was not sufficient to enhance the removal of considerable amount pyritic sulfur from the coal by magnetic separation at 2 T. Pyritic sulfur content was reduced by 37.46%. With the addition of 5% magnetite, which is an excellent microwave absorber mineral, microwave heating was enhanced and pyritic sulfur content of coal was reduced by 55.11%, by magnetic separation at magnetic field intensity of 2 T following the microwave heating. In addition, 21.54% decrease in ash content and 20.39% increase in calorific value also resulted.