Coal macerals and their separation methodologies – A review

Macerals are microscopically recognizable organic entities found in coal. On the basis of their optical properties they are classified into three categories, liptinite, vitrinite, and inertinite. Reactive macerals, Vitrinite and liptinite, are responsible for the thermoplastic nature of coal during coke formation. It is also found that these macerals can be used for making some high valued products such as carbon fiber, BTX, liquefaction and gasification feedstock. There are various methods applied by different researchers for coal maceral separation method. This review aims to discuss the various properties of coal macerals and the different methodologies adopted for their separation.