Improved Coking Coal Flotation with Vinyl Pyridine–Alkyl Sulfoxide Copolymers as Modifiers

Abstract

Coal flotation when using copolymers of vinylpyridine and alkyl sulfoxides as modifiers is investigated. When the modifiers are added to coal fines at a rate of 0.5–1.0 g/t, the flotation parameters are improved: more combustible coal mass is extracted with the concentrate; and less of the coal’s organic mass is lost with the flotation waste. The effectiveness of the modifier is determined by the quantity of sulfo groups and vinylpyridine groups in the macromolecule and also by its molecular mass. The flotation is best when using 50B modifier with molecular mass 17 500 and an increased sulfo group content in the macromolecule. The modifier is more effective when it is introduced in the flotation chamber before the collector. The flotation is improved because modifier molecules are adsorbed at the energetically active sections of the coal surface. Specifically, polar groups of the copolymer are attached by hydrogen bonds, with the hydrocarbon groups oriented into the aqueous phase. That ensures increase in hydrophobic properties of the coal before the collector is added. As a result, lower consumption of the collector is possible.