Chemical cleaning of coal by molten caustic leaching after pretreatment by low-temperature devolatilization

摘要

Pretreatment of coal by devolatization at temperatures ranging from about 420° C. to about 450° C. for from about 10 minutes to about 30 minutes before leaching with molten caustic leads to a significant reduction in carbonate formation, greatly reducing the cost of cleaning coal on a per ton basis.