Innovative flotation separation considering pores blocking to facilitate residual carbon recovery from coal gasification fine slag

Abstract

The conventional flotation of coal gasification fine slag has the dilemma of large collector dosage and low carbon recovery due to the developed porosity of the residual carbon. In this study, an innovative method to enhance the flotation recovery of residual carbon was proposed by pores blocking with pulverized coal. Flotation experiments were carried out to verify the effect of pore blocking on the recovery of residual carbon, and scanning electron microscope, X-ray photoelectron spectroscopy, and mercury intrusion porosimetry were used for mechanism analysis. The results showed that the addition of pulverized coal did play a role in pores blocking in the novel flotation, and its carbon recovery rate was improved by 14.11% (absolute value) compared to that of conventional flotation at the same ash content of the concentrates. On the one hand, the pulverized coal adheres on the pore openings on the residual carbon surface, thus preventing the collector adsorption into the pore channels; on the other hand, the adhesion of pulverized coal to the residual carbon surface increases the adsorption sites for collector. Therefore, pores blocking is beneficial for more adsorption of the collector on the outer surface of the residual carbon and thus improving its flotation recovery. This paper provides significant inspiration for efficient flotation of coal gasification fine slag.