Activation mechanisms of quartz flotation with calcium ions and cationic/anionic mixed collectors under alkalescent conditions

Probing the Interaction Mechanism of Sodium Oleate and Dodecyl Amine with Quartz Surfaces in the Presence of Ca2+ Ions by AFM Force Measurement

Quartz is a key raw material in high-tech fields (such as photovoltaics and semiconductor microelectronics), and the most efficient extraction method of quartz is mineral flotation. Quartz activation plays a crucial role in mineral flotation. However, the mechanism underlying the process remains unclear, and the role of additional metal ions is controversial. In this study, the interaction forces between the quartz surface, the dodecylamine (DDA) cation/sodium oleate (NaOL) anion mixed collectors, and Ca2+ were analyzed using atomic force microscopy in order to systematically explore the activation process of quartz flotation. The results confirmed that the activation process was initialized from NaOL, which was adsorbed on the surface of a calcium-covered quartz surface. The existence of DDA inhibited the binding of Ca2+ to NaOL so that more Ca2+ was adsorbed on the quartz surface to provide the adsorption site for NaOL. Moreover, the best adsorption condition of Ca2+ + NaOL + DDA mixed solution was analyzed by quartz crystal microbalance with dissipation, and it demonstrated that the most stable chemisorption environment on the quartz surface was at pH 11.0. In these circumstances, Ca2+ could first adsorb in a point-like manner on the quartz surface, which was then adsorbed with a mixture of NaOL and DDA. This result showed that, at a specific pH, Ca2+ could encourage the coadsorption of cationic/anionic mixed collectors on quartz. This work provides an important new understanding of the intermolecular interactions that take place during complex mineral flotation processes between chemical additives and mineral surfaces. The methodology used in this study can be easily adapted to different interfacial processes, including water treatment, membrane technology, bioengineering, and oil production.

Effects of Al(III) Ions at Magnetite Flotation from Quartz by Dodecylamine Al(III)

The flotation separation of magnetite and quartz is a long-term challenge for the beneficiation industry. For high-quartz magnetite, conventional flotation shows poor separation effect, resulting in the waste of resources and low flotation efficiency. In this paper, dodecylamine acts as a collector and Al(III) ions in water act as a depressant to selectively separate magnetite and quartz at high alkalinity. The experimental results are analyzed by a micro-flotation experiment, solution chemical calculation, zeta potential, contact angle measurement, and Fourier transform infrared spectroscopy (FTIR). The results of micro-flotation experiments showed that Al(III) ions in water inhibited magnetite more strongly than quartz. The calculation results of solution stoichiometry and zeta potential showed that the phase formed by Al(III) ions on the surface of magnetite and quartz are mainly Al(OH)3(s), which covers the surface of magnetite and quartz, The contact angle measurement results showed that with the addition of Al(III) ions, the contact angle of magnetite varies significantly than that of quartz, and the floatability of magnetite is lower than that of quartz. The FT-IR results further indicated that the addition of Al(III) ions could hinder the adsorption of dodecylamine on the magnetite surface. Meanwhile, the addition of Al(III) ions has no obvious effect on the adsorption of dodecylamine on the quartz surface.