Coal middling retreatment using high voltage pulses technique: selective liberation mechanism

Abstract

ABSTRACT With combined efforts from the mineral liberation analyzer (MLA), elementary analysis and sulfur speciation analysis, this study expands upon coal fragmentation using high voltage pulse (HVP) by incorporating an understanding about deportment of specific minerals due to density behavior. Mineral characteristics showed that the minerlisation of middlings sample was predominantly banded, and pyrite was most of all associated with the mineral matter, to a lesser extent, with the organic matter. In addition, it was found that the pyritic sulfur attained a higher propensity for the heavy densities than the total sulfur, and the results were supported by speciation analysis. For Test 3, the total sulfur (0.86%) predominantly arose from organic sulfur due to the condensation of organic matter in the −1.3RD fraction, whereby the pyritic sulfur merely accounted for 25.80% of the total sulfur. It is concluded that the metalliferous grain-induced breakdown resulted in pulse selectivity between the middling particles. The improvement in coal middlings reprocessability (deashing and desulfuration) predominantly arose from the generation of cracks/microcracks. The results of this study have shown that the high voltage pulse (HVP) technique holds considerable promise for coal middlings reprocessing in comparison with the mechanical crushing method.