Removal of quartz from hematite by reverse flotation using cationic collectors is an effective approach for iron concentrate upgrading. In this paper, three hydroxyl-containing cationic collectors, i.e., N-Dodecylethanolamine (NDEA), N-Dodecylpropanolamine (NDPA), and N-Dodecylbutanolamine (NDBA), were synthesized and characterized. The flotation performance and the structure-performance relationship of the collectors were systematically investigated by micro-flotation experiments and various surface analysis techniques. At the concentration of 20 mg/L, the flotation recoveries of quartz by NDEA, NDPA, and NDBA were 94.9 %, 93.5 %, and 93.3 %, respectively. Collectors with shorter hydroxyl-substituted carbon chains exhibited stronger collecting ability and enhanced hydrophobicity of quartz surface, as confirmed by contact angle measurements. Zeta potential measurements and molecular simulations revealed that the collectors adsorb onto the quartz surface through electrostatic and hydrogen bonding interactions. The introduced hydroxyl groups could enhance the formation of hydrogen bonds between collectors and mineral surface. However, as the carbon chain length increases, the adsorption area of a single collector on the mineral surface increases, the number of collector molecules adsorbed per unit area decrease, reducing the collecting ability of the collector for quartz. This research could provide theoretical guidance for the design of novel cationic collectors.

中文翻译：

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3种含羟基阳离子捕收剂的合成、浮选行为及构效关系

使用阳离子捕收剂通过反向浮选从赤铁矿中去除石英是铁精矿提质的有效方法。本文合成并表征了三种含羟基的阳离子捕收剂，即 N-十二烷基乙醇胺 （NDEA）、N-十二烷基丙醇胺 （NDPA） 和 N-十二烷基丁醇胺 （NDBA）。通过微浮选实验和各种表面分析技术，系统研究了捕收剂的浮选性能和结构-性能关系。浓度为 20 mg/L 时，NDEA、NDPA 和 NDBA 对石英的浮选回收率分别为 94.9 %、93.5 % 和 93.3 %。接触角测量证实，具有较短羟基取代碳链的捕收剂表现出更强的收集能力和增强的石英表面疏水性。Zeta 电位测量和分子模拟表明，捕收剂通过静电和氢键相互作用吸附到石英表面。引入的羟基可以增强捕收剂和矿物表面之间氢键的形成。然而，随着碳链长度的增加，单个捕收剂在矿物表面的吸附面积增加，单位面积吸附的捕收剂分子数量减少，降低了捕收剂对石英的收集能力。本研究可为新型阳离子捕收剂的设计提供理论指导。