Enhancing the purity of magnesite ore powder using an ethanolamine-based collector: Insights from experiment and theory

Abstract

Magnesite ore powder is the primary raw material used to prepare refractory magnesia. With the depletion of high-grade magnesite, methods to reduce the impurities and improve the quality of magnesite ore powder are urgently required. In this study, an ethanolamine-based surfactant, bis (2-hydroxyethyl) dodecylamine (BHDA), was first introduced into the flotation of magnesite ore as a novel collector, and the possibility of improving the purity of the ore was investigated by experiment and theory. Flotation tests, X-ray photoelectron spectroscopy, Fourier-transform-IR spectroscopy, and zeta potential measurements were carried out to study the behaviors and mechanisms by which the collector enhances the purity of magnesite ore powder. The flotation results revealed the noticeable difference in the floatability of quartz, magnesite, and dolomite when combined with the collector over a wide range of pulp pH values (4.18–9.17). The analytical results obtained from FTIR spectra, XPS, and zeta potential measurements indicate that BHDA was readily adsorbed on the surface of quartz, mainly by electrostatic and hydrogen bonding interactions, whereas it was adsorbed on the surfaces of magnesite and dolomite by weak electrostatic interactions. By introducing a hydroxyethyl group to the tertiary amine collector, more hydrogen bonds can form with the surface of quartz, strengthening the adsorption stability. Thus, compared to the traditional collector, dodecylamine, BHDA showed better desilication and purification performance for magnesite ore powder. Meanwhile, our results show that the simpler reagent system and process flow makes BHDA promising for the industrial purification of magnesite ore powder.