Experimental study of coal liberation: Electrical disintegration versus roll-crusher comminution

Preferential breakage, where the boundary of mineral particles and coal substances are selectively broken up, is an effective comminution method for poor liberation coals such as middling coal subjected to jig treatment. A comparison of electrical disintegration (ED) product and roll crusher product of Nantun (China) clean coal was carried out in this study. Coal particles of 4 to 8 mm diameter with specific gravities of 1.35 to 1.45 were used as the feed and the crushed product was classified into 12 fractions by size and specific gravity and analyzed for ash and mineral content using a norm calculation method. The generation ratios of light clean coal and heavy waste fractions in the ED product were higher than in the roll crusher product and this indicates that ED improved the mineral liberation. The microscopic observations supported this. The norm calculation results showed that calcite, dolomite, and pyrite were concentrated in the heavy and fine fractions, a behavior that is different from that of kaolinite.