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.

浮选是分离石英和长石最有效的方法，但常规浮选通常在酸性或碱性条件下进行，对环境造成污染。本研究提出了一种在中性 pH 条件下从石英长石混合矿物中直接浮选石英的新方法。该方法通过乙二胺（EDA）和聚醚胺（PEA）在颗粒表面的竞争吸附来实现矿物的分离。通过浮选实验研究了EDA和PEA对石英和长石分离的影响。使用傅里叶变换红外光谱仪 (FTIR)、X 射线光电子能谱仪 (XPS)、X 射线粉末衍射仪 (XRD)、电感耦合等离子体发射光谱仪 (ICP-OES) 和 X 射线荧光光谱仪 (XRF) 进行测试, 浮选行为, 并对吸附机理进行了分析。对单一矿物的浮选实验结果表明，EDA能有效抑制长石的浮选，扩大石英与长石的浮选回收率之差，达Δ=77%。混合矿物浮选实验结果表明，EDA和PEA结合使用可以有效分离石英和长石。对于泡沫产品，2-F-Qtz的石英含量达到97.42%，SiO 混合矿物浮选实验结果表明，EDA和PEA结合使用可以有效分离石英和长石。对于泡沫产品，2-F-Qtz的石英含量达到97.42%，SiO 混合矿物浮选实验结果表明，EDA和PEA结合使用可以有效分离石英和长石。对于泡沫产品，2-F-Qtz的石英含量达到97.42%，SiO₂级为 99.12%，石英浮选回收率为 70.20%。沉降产品4-S-Fsp的长石含量达到94.77%，SiO ₂品位为69.50%，长石浮选回收率为87.45%。提出了一种竞争吸附模型来解释在中性 pH 条件下石英长石混合矿物中石英直接浮选的机理。