The Improvement of Grindability and Floatability of Oxidized Coal by Microwave Pre-treatment

Abstract

A laser particle size analyzer was used to analyze the particle size composition of −200 mesh from the coals for different grinding time and/or different microwave pre-treatment time. Fourier-transform infrared was used to show the changes in the main functional chemical groups of oxidized coal upon grinding and/or microwave pre-treatment. All of these were recognized by the flotation behavior using an XFD1.5L flotation cell. Under the same grinding time, −200 mesh coals will be finer when microwave pre-treatment increases. Microwave pre-treatment and grinding improve the floatability of oxidized coal by reducing the content of –OH and/or increasing the content of –CH₃. Combustible recovery increases or decreases proportionately with a yield of −74 + 11 μm.

Keywords:

• flotation
• Fourier-transform infrared
• grinding
• microwave
• particle size