Adsorption behaviors and mechanisms of quaternary ammonium salt collectors on quartz samples with different particle sizes

Abstract

In this study, the flotation behavior of quartz samples with different particle sizes was systematically studied by conducting a microflotation experiment wherein different quaternary ammonium salt (QAS) collectors were used. The mechanism of QAS adsorption on the surfaces of the quartz samples was revealed by adsorption experiments and micro-polarity characteristics at the quartz-water interface. The microflotation experiment showed that the carbon chain length of the QAS collectors and the particle sizes of the quartz samples had a significant effect on flotation recovery. Long carbon chain collectors, tetradecyltrimethylammonium chloride (TTAC) and cetyltrimethylammonium chloride (CTAC), exhibited a better collection capability than that exhibited by short carbon chain collectors, decyltrimethylammonium chloride (103C) and dodecyltrimethylammonium chloride (DTAC). The adsorption experiments showed the adsorption amount of CTAC and DTAC on the surfaces of the quartz increased with decrease in quartz particle size. The adsorption isotherms of QAS collectors on the quartz particles were consistent with the typical “double plateau model.” The shape of the adsorption isotherm was affected by the particle sizes of the quartz and the carbon chain length of the collector. A pyrene fluorescence test showed that the maximum value of I3:I1 (I3:I1max) of the long carbon chain CTAC was larger than that of the short carbon chain DTAC. When the I3:I1 max was reached, the required concentration of CTAC was less than that of DTAC. With the increase in the DTAC concentration, the fluorescence intensity of pyrene in the supernatant initially decreased, and then increased, thereby indicating that the DTAC adsorption on the surfaces of the quartz particles gradually saturated.