Experimental study of coal washability using float and sink test

Abstract

Pakistani coal is characterized by large amount of mineral matters especially pyrite, which restricts its use in power generation and process industry. High ash contents in coal create problems in terms of slagging, fouling, clinker formation and environmental pollution. High ash content of the coal will affect the coal applications, in order to reduce ash the contents of coal, there is need to clean the coal. In this experimental study effect of dense medium, specific gravity, settling time and particle size on coal washability have been carried out. Experimental study showed that maximum clean coal float fraction was separated out at particle size of 60 mesh. The maximum yield of clean coal is 86.1 % obtained in float and sink test. Settling time also influenced directly on float fraction, float and sink fraction became almost constant at 16 hours. In present research lowest ash contents of clean coal is reduced from 36.38 % to 11.1% which is acceptable for further utilization of process industry.