The quaternary ammonium salt collectors display great application prospects in minerals flotation, and introducing the second polar group has been an effective method to enhance the performance of flotation reagents. In this study, the hydroxyl group was introduced into quaternary ammonium salt to design and synthesize a novel containing hydroxyl group quaternary ammonium salt collector dodecyl hydroxyethyl dimethyl ammonium bromide (DHDAB) for the flotation desilication of hematite, which was characterized by Fourier transform infrared spectroscopy (FT-IR), mass spectrometry, and nuclear magnetic resonance (NMR). Based on the reverse flotation desilication system of hematite, the differences in flotation performance of DHDAB and dodecyl trimethyl ammonium bromide (DTAB) were compared, and the flotation separation behaviors of DHDAB to quartz and hematite were also studied by micro-flotation tests. Both DHDAB and DTAB showed great pH adaptability, and DHDAB had better flotation selectivity than DTAB through flotation studies. The selective flotation separation mechanism of DHDAB to quartz and hematite was also analyzed by zeta potential tests, FT-IR analyses, contact angle tests, X-ray photoelectron spectroscopy (XPS) tests and density functional theory (DFT) analyses, meanwhile, the influence mechanism of the hydroxyl group on the performance of collectors was also studied. The contact angle test results showed that the surface hydrophobicity of quartz and hematite treated by DHDAB was more different. These results also indicated that DHDAB was selectively adsorbed on the mineral surface mainly through electrostatic attraction and hydrogen bonding. Introducing the hydroxyl group into DHDAB could produce stronger hydrogen bonding, increase the interaction site with the quartz surface, and increase the steric hindrance to enhance the selectivity.

季铵盐类捕收剂在矿物浮选中具有广阔的应用前景，引入第二极性基团已成为提高浮选剂性能的有效方法。本研究在季铵盐中引入羟基，设计合成了一种新型含羟基季铵盐捕收剂十二烷基羟乙基二甲基溴化铵（DHDAB），用于赤铁矿浮选脱硅，并通过傅里叶变换红外光谱（ FT-IR)、质谱和核磁共振 (NMR)。基于赤铁矿反浮选脱硅体系，比较了DHDAB与十二烷基三甲基溴化铵（DTAB）浮选性能的差异，并通过微浮选试验研究了DHDAB对石英和赤铁矿的浮选分离行为。DHDAB 和 DTAB 均表现出良好的 pH 适应性，通过浮选研究，DHDAB 的浮选选择性优于 DTAB。通过zeta电位测试、FT-IR分析、接触角测试、X射线光电子能谱（XPS）测试和密度泛函理论（DFT）分析，分析了DHDAB对石英和赤铁矿的选择性浮选分离机理，同时，还研究了羟基对捕收剂性能的影响机理。接触角测试结果表明，经DHDAB处理的石英和赤铁矿的表面疏水性差异较大。这些结果还表明，DHDAB主要通过静电引力和氢键作用选择性吸附在矿物表面。在DHDAB中引入羟基可以产生更强的氢键，增加与石英表面的相互作用位点，增加空间位阻，从而提高选择性。