铝硅矿物-气泡间液膜稳定/失稳与矿物界面位点性质的耦合机制研究

Bauxite is an important strategic resource in the development of aluminum industry. The bauxite resources in China are dominated by diasporic ores with high silicon content. The mineralization selectivity of aluminum-containing valuable mineral and siliceous gangue minerals with bubbles is poor, which restricts the high-efficiency desiliconization of bauxite through flotation. The stability/instability of the liquid film between particles and bubbles determines whether mineralization can occur. Taking diaspore and kaolinite as research objects, the project will carry out with the mineral interface sites properties as the entry point to study the mechanism of stability/instability of the liquid film between aluminum/silicon mineral and bubble, and explore the regulation basis of expanding the adhesion difference between the two minerals with bubbles. Firstly, the structural parameters and density distribution of mineral interfacial sites will be studied by X-ray photoelectron spectroscopy combined with electric double layer theory. Then, the liquid film structure, thinning rate, and microscopic force between minerals and bubbles will be studied using the frequency vibration spectrum, liquid film analysis system, and atomic force microscope; the stability of the liquid film will be quantified through multi-parameter integration, and the coupling relationship between liquid film stability and interfacial site properties will be established through mathematical modeling. Finally, the influence of chemical modification of interfacial sites on the thinning dynamics of liquid film and the nano-hydrophobic force of interface will be explored, and the mechanism of liquid film instability and selective adhesion mechanism between aluminum mineral-bubble and silicon mineral-bubble will be obtained from the perspective of promotion and masking of the interfacial sites. This research will provide theoretical support for expanding the floatability difference between aluminum mineral and silicon mineral thereby improving the flotation desiliconization effect of bauxite.

铝土矿是铝工业发展中的重要战略资源，我国铝土矿以高硅的一水硬铝石型矿石为主，其中的含铝有价矿物与含硅脉石矿物的气泡矿化选择性差，制约铝土矿高效浮选脱硅。矿粒-气泡间液膜稳定/失稳效应决定矿化能否发生，项目以一水硬铝石和高岭石为研究对象，以矿物界面位点性质为突破口研究铝硅矿物-气泡间液膜稳定与失稳机理，探索扩大两种矿物与气泡粘附差异的调控基础。首先利用X射线光电子能谱，结合双电层理论研究矿物界面位点结构参数及密度分布；而后利用和频振动光谱、液膜分析系统、原子力显微镜等研究矿物-气泡间液膜结构、薄化速率及微观力，通过多参数整合量化液膜稳定性，构建其与矿物界面位点性质的耦合关系；最后探索界面位点化学改性对液膜薄化动力学及界面纳米疏水力的影响规律，从界面位点促活与掩蔽角度得出铝硅矿物-气泡间的液膜失稳机理和选择性粘附调控机制。项目可为扩大铝硅矿物的可浮性差异进而改善铝土矿浮选脱硅效果提供理论支撑。

铝土矿是铝工业发展中的重要战略资源，其浮选脱硅过程实际上是有价矿物（一水硬铝石）与脉石硅酸盐矿物（高岭石、伊利石和叶腊石等）之间的分离过程，铝硅矿物的气泡矿化选择性差是制约铝土矿高效浮选脱硅的瓶颈。本项目以矿物界面位点性质为切入点，围绕粘附过程中矿物-气泡间液膜的薄化失稳等矿化核心环节，利用高速动态显微摄像系统、诱导时间测定仪、XPS、zeta电位仪、接触角测量仪等先进分析测试手段，综合运用矿物加工学、界面化学等多学科的交叉方法，对铝硅矿物界面基本性质及界面位点调控、铝硅矿物-气泡间液膜稳定性及其薄化动力学、基于界面位点化学调控的铝硅矿物-气泡间液膜的失稳机制进行了研究。探索出了铝硅矿物界面位点性质的调控方法，建立了液膜排液速率与药剂吸附速率之间的关系模型，研究了捕收剂在矿物表面的吸附动力学，得出有价矿物与脉石矿物对捕收剂分子的吸附速率存在差异。探究了六偏磷酸钠（SHMP）调控铝硅矿物与气泡间液膜失稳的机理，得出在反浮选中可使用高用量的SHMP来使一水硬铝石与气泡之间的粘附得到有效抑制，而硅酸盐矿物与气泡之间的粘附被抑制程度较低；在正浮选中使用少量的SHMP即可实现对硅酸盐矿物与气泡之间粘附的有效抑制，而一水硬铝石与气泡之间的粘附被抑制的程度较低。探明了硫酸预处理能够降低一水硬铝石表面的液膜排液速率以及十二胺（DDA）在其表面的吸附速率，而对三种硅酸盐矿物的影响情况相反；建立了连接矿物Zeta电位与矿物表面活性位点密度的GCS模型，拟合得出硫酸预处理改变了铝硅矿物表面的活性位点密度，并从表面活性位点的角度对硫酸预处理的调控机理进行了解释。发现了酸蚀有利于石英的阴离子浮选而不利于阳离子浮选，阐明了酸蚀增加阴离子捕收剂吸附活性位点而减少阳离子捕收剂吸附电荷从而双向影响石英界面液膜失稳的理论机制。通过本研究得出了在微纳米尺度上铝硅矿物与气泡之间的液膜薄化规律及失稳调控机制，可为改善铝硅矿物之间的浮选分离效果提供理论支撑。