Enhancement of ultrafine coal slime flotation using high-shear pretreatment and polyvinylpyrrolidone

Abstract

ABSTRACT Flotation has been used to treat coal over the last century. However, the conventional flotation condition can hardly be applied to ultrafine coal slime (UCS). An alternative combined method, which has the potential to improve UCS separation efficiency, is using high-shear pretreatment (HSP) and polymer regulator. Presented in this paper are the findings from an investigation into the flotation performance and aggregate characteristics of UCS with the assistance of HSP and polyvinylpyrrolidone (PVP). Electrokinetic, laser particle size, and rheology experiments were employed to analyze the influence of HSP and PVP on ultrafine particles. The UCS studied has a high ash content of 53.62%. The flotation results were analyzed through flotation efficiency and selectivity indexes. The results show that the flotation concentrate has less gangue entrainment and high combustible recovery, low ash content (12.74%) and higher flotation efficiency (66.26%) were obtained. Moreover, the results of flotation kinetics illustrate the advantage of using PVP, which improves the cumulative combustible recovery and flotation rate. The introduction of HSP was conducive to the improvement of separation selectivity. These findings provide fundamental insights into the effect of HSP and PVP on ultrafine particles and offer an effective technique for the enhancement of UCS flotation.