剪切强化煤泥浮选调浆的作用机理及调控研究

As an important factor, fluid shear force can improve the hydrophobic flocculation of coal particles, the dispersion of collector agents and its adsorption on coal particles during flotation conditioning. But excessive shear may result in sliming and reduce the flotation effect. Therefore, further study the impact of fluid shear rate on the mechanism of conditioning and its regulation has very important significance for flotation conditioning. This project researches form fluid dynamic parameters. Characteristic parameters in macro and micro flow field will be studied by the PIV technology and numerical simulation under different structure and operation parameters and the control model of the fluid shear and velocity with the main structure and operation parameters will be established. Then the effect of the fluid shear rate and velocity of flow field on interfacial behavior and flotation process will be explored. The relationship model of agent dispersion, adsorption and particle selective agglomeration with the characteristic parameters will be established by the analysis of conditioning mechanism. Based on the particle characterization, fluid shear force and velocity, the control equation of interfacial behavior will be built to control the conditioning process. This study reveals the agitation mechanism form flow field characteristics and interfacial behavior, constructing the theoretical and fluid dynamic basis for design and optimization on conditioning process.

调浆过程中流体的剪切是影响调浆效果重要的因素之一，剪切可以促进药剂的分散和药剂在颗粒表面的吸附以及颗粒之间的选择性疏水絮凝，但过度的剪切会造成泥化，降低浮选效果。因此，深入研究剪切对煤泥浮选调浆的强化机理及其调控机制对于实现煤泥高效调浆具有重要的意义。本项目从流体动力学的角度出发，首先通过PIV技术和数值模拟方法研究不同结构和操作参数时宏观和微观流场特征参数的变化，分析影响流体剪切率场和速度场分布的主要结构操作参数并建立相应的调控模型；然后研究不同剪切流场时调浆的界面行为及其浮选过程动力学，分析流体剪切率和速度对调浆界面行为的影响及其作用机理，建立基于颗粒性质、流体剪切率和流体速度的界面行为调控模型。最后通过对界面行为和流场动力学参数的调控，实现对调浆过程强化机理的调控。本研究从流场特性和界面行为揭示了浮选调浆强化机理并建立调控模型，为煤泥浮选调浆过程设计和优化建立了理论和流态化基础。

高效的调浆过程是实现高效浮选的前提，而调浆过程中的流体剪切是决定调浆效果的关键。剪切有利于促进煤泥浮选过程中药剂的乳化和分散，减少粗颗粒煤表面的细泥罩盖，提高药剂在颗粒表面的吸附效果，但过度的剪切会降低调浆浮选效果。因此，深入研究剪切对煤泥浮选调浆的强化机理及其调控机制是实现煤泥高效调浆和浮选的基础。本项目通过数值模拟，对搅拌桶内部流场特性进行了分析，研究了固-液两相流条件下叶轮转速对不同性质颗粒固-液两相速度差的影响，通过扫描电镜、FBRM在线粒度分析仪研究了不同调浆条件下，颗粒表面细泥罩盖和颗粒粒度等界面行为的变化，通过实验室浮选试验研究了不同剪切条件下，煤泥浮选动力学的变化。项目揭示了搅拌桶内固-液两相颗粒速度差随叶轮转速、颗粒粒度和密度的变化规律，建立了煤颗粒与非极性油的碰撞概率和药剂分散度之间的模型，揭示了煤泥浮选调浆强化机理。项目研究成果可为煤泥浮选调浆过程设计和优化提供一定的理论基础，对其它金属矿和非金属矿的浮选调浆也具有一定的参考意义。