Enhanced effect of depressant for the flotation separation of chalcopyrite from pentlandite via chemical and spatial selectivity

Abstract

Focusing on the difficulty of separating chalcopyrite from pentlandite, this study pioneers a chemical-spatial dual-selectivity strategy to design depressants for pentlandite. Based on this strategy, two small-molecule organic depressants, 4-hydroxyamino-4-oxobut-2-enoic acid (HOAOEA) and 4-hydroxyamino-4-oxobutanoic acid (HOAOB), were synthesized. The advantages of the chemical-spatial dual-selectivity strategy in the design of effective small-molecule depressants were explored through a comparative study of the flotation and adsorption behavior of HOAOEA and HOAOB. DFT calculations revealed that HOAOEA with chemical-spatial selectivity allowed the simultaneous coordination of Ni/Fe sites on the surface of pentlandite through electron delocalization effect and planar adsorption structures and the formation of multilayered adsorption through intermolecular π-π interactions, resulting in a dense hydrophilic film on the mineral surface. The flotation results demonstrated that HOAOEA was an excellent depressant by selectively depressing the flotation of pentlandite with better performance than HOAOB. This study not only pioneers the application of a chemical-spatial dual-selectivity design strategy for developing small-molecule depressants in mineral flotation, but also facilitates the efficient exploitation of copper-nickel resources.