Application of competitive adsorption of ethylenediamine and polyetheramine in direct float of quartz from quartz-feldspar mixed minerals under neutral pH conditions

Abstract

Flotation is the most effective way to separate quartz and feldspar, but conventional flotation is usually achieved under acidic or alkaline conditions, which causes pollution to the environment. This study proposes a new method for a direct float of quartz from quartz-feldspar mixed minerals under neutral pH conditions. The method achieves the separation of minerals by competitive adsorption of ethylenediamine (EDA) and polyetheramine (PEA) on the particle surface. The effect of EDA and PEA on the separation of the quartz and the feldspar was investigated by flotation experiments. Using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray powder diffractometry (XRD), Inductively coupled plasma-optical emission spectrometry (ICP-OES), and X-Ray Fluorescence Spectrometer (XRF) tests, the flotation behavior, and adsorption mechanism were analyzed. The result of the flotation experiments of a single mineral shows that EDA can effectively depress the flotation of the feldspar and enlarge the difference between the flotation recovery of the quartz and the feldspar, up to Δ = 77%. The result of flotation experiments of the mixed minerals shows that the combination of EDA and PEA can effectively separate the quartz and the feldspar. For the froth products, the quartz content of 2-F-Qtz reaches 97.42% and the SiO2 grade is 99.12% at a quartz flotation recovery of 70.20%. For the sink products, the feldspar content of 4-S-Fsp reaches 94.77% and the SiO2 grade is 69.50% at a feldspar flotation recovery of 87.45%. A competitive-adsorption model is proposed to explain the mechanism of the direct float of the quartz from the quartz-feldspar mixed minerals under neutral pH conditions.