Intensification of interfacial adsorption of dodecylamine onto quartz by ultrasonic method

Abstract

Besides being a versatile mineral resource, quartz is also a common gangue mineral in mineral separation. The separation and enrichment of quartz minerals are particularly important in industrial production. Cationic surfactants of dodecylamine (DDA) is mainly used as collector in the quartz flotation as it consists of hydrophilic amino group which attach to the quartz surface, and the hydrophobic carbon-chain groups which make the quartz hydrophobic. So the adsorption behaviour of DDA is vital to the quartz flotation. In this paper, we examine an ultrasonic method for enhancing the adsorption of DDA in the froth flotation of quartz. The adsorption mechanism of the DDA collector onto quartz is systematically investigated via Fourier transform infrared spectroscopy (FTIR) measurements, adsorption heat measurements, adsorption amount tests, contact angle analysis, and induction time tests, and X-ray photoelectron spectroscopy (XPS) analysis. Our results indicate that ultrasonication does not change the functional groups of the DDA, however, the adsorption intensity with an adsorption heat of −26.56 J/g between ultrasonically treated DDA and quartz is fairly large. The adsorption amount of DDA onto quartz significantly increases after ultrasonically treated without increasing its concentration, and the maximum contact angle of quartz particles after conditioning by the ultrasonically treated DDA increase from 53.07° (for untreated DDA) to 66.13° at the concentration of 8 × 10−5 mol/L. In bubble attachment tests, the induction time between quartz particles and a bubble is observed to decrease from 30 ms to 20 ms compared to that without ultrasonic treatment, and coupled with a greater attachment performance of the DDA solution with ultrasonic treatment. And the XPS analysis confirms the adsorption of ultrasonically treated DDA onto quartz surface. Further, we perform micro-flotation tests to verify the enhanced adsorption of the ultrasonically treated collector onto the quartz surface for different initial concentrations; the results indicate that ultrasonication of DDA significantly improves the flotation recovery of quartz, particularly at moderate collector concentrations. This study is beneficial for understanding the interfacial adsorption and the ultrasonic intensification of DDA onto quartz particles.