Investigation on mechanism of intensifying coal fly ash froth flotation by pretreatment of non-ionic surfactant

The purpose of this research was to investigate the mechanism of intensifying coal fly ash flotation by pretreatment of the non-ionic surfactant Triton X-100 (TX100). Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy were used to analyze the characteristics of the unburned carbon samples to clarify why unburned carbon floats with difficulty. An attachment time analyzer and surface free energy measurement were used to analyze the surface characteristic changes of the unburned carbon before and after pretreatment with TX100. A Foamscan analyzer was used to study the synergistic effects of TX100 and 2-Octanol on the foam properties. The obtained results demonstrate that the unburned carbon surface is strongly hydrophilic owing to the abundance of oxygen-containing functional groups as well as its rough and porous surface. The pretreatment of TX100 can improve the hydrophobicity of the unburned carbon surface significantly in order to improve the unburned carbon recovery. Moreover, the compound of TX100 with 2-Octanol can improve the foamability and foam stability, as well as decrease the bubble size, which can further promote the coal fly ash flotation performance.