Desulfurization of mezino coal using combination of ‘flotation’ and ‘leaching with potassium hydroxide/methanol’

Mezino coal contains a high percentage of ash and both organic and inorganic sulfur. The ash and sulfur contents can be reduced using physical–chemical and chemical methods. ‘Froth flotation’ is a physical–chemical method that is capable of reducing inorganic sulfur and the ash content of coal. In this research, reducing the ash content of mezino coal by 83%, inorganic sulfur by 72% and its total sulfur content by 63% using flotation in alkaline pH and in the presence of copper ion was successful. The coal flotation obtained was 73%. The coal concentration obtained from flotation was leached using potassium hydroxide/methanol mixture and its total sulfur and ash contents were reduced by approximately 33 and 8%, respectively. Hence, using the combination of the two mentioned methods, the total sulfur and ash contents of coal were reduced by 82.50 and 82.34%, respectively. It is an unprecedented and welcome result compared to the previous work.