Flotation separation of quartz and dolomite from collophane using sodium N-dodecyl-β-amino propionate and its adsorption mechanism

Abstract

Flotation is the most widely used method to effectively separate dolomite and quartz from collophane. Conventional amine collectors can’t effectively remove silicate minerals due to their poor selectivity, thick foam and weak collective performance. In this work, a novel amphoteric collector sodium N-dodecyl-β-amino propionate(C12Giy) was synthesized by methyl acrylate method. The strength of C12Giy's collective performance for three minerals was investigated by the micro-flotation test. In addition, the adsorption mechanism of C12Giy on the surface of three minerals was studied by zeta potential test, infrared spectroscopy and XPS test. The micro-flotation results show that C12Giy has a strong collection performance for dolomite and quartz, but weaker for collophane. It was also noted that when the pH is 3 and the concentration of C12Giy is 30 mg/L, collophane and quartz can be effectively separated. Similarly, when the pH is 5 and the C12Giy concentration is 30 mg/L, the effective separation of collophane and dolomite can be achieved. Zeta potential test and infrared spectrum analysis showed that C12Giy was adsorbed on surface of collophane and quartz by electrostatic attraction at pH= 3, while it is chemical adsorption on the surface of dolomite at pH= 5. The XPS analysis further indicated that the exposed magnesium ions on the surface of dolomite are crucial for the selective adsorption of C12Giy on dolomite. On the one hand, Magnesium ions, as an important component on the surface of dolomite rather than collophane, enhance the chemical adsorption of C12Giy on dolomite. On the other hand, it increases the total interaction energy of dolomite with quartz particles by adding C12Giy, which in turn increases their electrostatic attraction with the bubbles. Therefore, C12Giy can be utilized as a potential collector to separate dolomite and quartz from collophane.