多流态柱浮选过程的能量状态及对煤粒-气泡矿化行为的影响

With the advantages of lower separation particle size and better selectivity, the Cyclone-Static Microbubble Flotation Column (FCSMC) has great potential in fine coal preparation. However, China's fine coal is gradually characterized by tiny size, high ash and poor selectivity, the higher requirements of fine coal separation process is proposed. The mineralizationbetween coal particles and air bubbles dominates the whole flotation process, and also affects the separation efficiency. In order to reduce energy consumption of flotation process and improve the adaptability of flotation column on difficult floatable coal, this project will embark from the process energy, the countercurrent flow, cyclone and jet flow of the flotation column are chosen as the research object. In order to clarify action mechanism of each flow regime, the three integrated flow regimes will be studied separately. The computational fluid dynamical models of gas-liquid-solid three phases will be estabilished, and their flow information and energy state will be analyzed. The main characteristic parameters of coal samples will be analyzed, and its difficult-to-float mechanisms will be interpreted. The collision, attachement, and detachment processes between particles and bubbles will be observed and measured. The acting force between them will be measured, the internal link between energy input and bubble mineralization mechanism will be proved. After the investigations, the interaction mechanisms between difficult-to-float coal particles and bubbles will be explored. Meanwhile, the above research achievements will be beneficial to match the energy input and fine coal separation process, reduce energy consumption of flotation process, improve the efficiency of fine coal flotation, and enrich theoretical research systems of multi-flow separation process.

旋流-静态微泡浮选柱以其分选粒度细、选择性好等优点，在细粒煤泥处理上体现出较大潜力。然而，我国煤泥呈现微细化、高灰、选择性差等难选特点，对煤泥分选过程提出了更高要求。煤粒与气泡的矿化支配着浮选全过程，影响分选效率。为降低浮选过程能耗和提高浮选柱对难选煤泥的适应性，本项目从过程能量的角度出发，选取浮选柱中的逆流、旋流与射流为研究对象，为明确各流态的作用机理，将集成的三种流态单独进行研究：建立多流态柱分选过程气-液-固三相流场的计算流体动力学模型，分析流场信息与能量状态；分析煤样主要特征参数，阐释其难浮机理；分析煤粒-气泡间碰撞、粘附与脱附过程，测量煤粒-气泡间作用力，探明能量输入与气泡矿化机理之间的内在联系。通过探索难浮煤粒与气泡之间的作用机理，实现能量输入与煤泥分选过程之间的匹配，达到降低浮选过程能耗、提高煤泥浮选效率、丰富多流态分选过程理论研究体系的目的。

气泡矿化动力学主导浮选过程，能量是浮选过程实现的重要保证。浮选过程中颗粒与气泡在气液固界面发生复杂的碰撞、粘附、脱附等物理化学作用。多流态柱浮选过程能量状态及煤粒-气泡矿化行为研究有助于浮选过程设计及浮选设备结构优化。项目分别设计了以逆流、旋流、管流为主要矿化方式的分选过程。利用微观湍流动能以及湍流耗散率衡量浮选过程内部能量状态，管流分选过程中的平均湍流动能和湍流耗散率值最大，逆流最小；从逆流、旋流到管流的多流态柱分选过程，能量状态从低到高梯级强化。构建了气泡尺寸测量系统，气泡直径随湍流耗散率的提高而减小。从浮选动力学角度计算湍流耗散率条件下颗粒与气泡作用过程中的碰撞、粘附、脱附及捕获概率，碰撞、粘附、脱附及捕获概率随颗粒粒度增加而增加，随湍流耗散率提高而增加；相同颗粒粒度条件下，管流分选过程中颗粒与气泡的碰撞、粘附、脱附及捕获概率最大，逆流分选最小。构建了煤泥柱式分选试验系统，通过煤泥浮选试验揭示了与不同流场环境相适配的煤泥物性特征，多流态柱浮选过程对于难浮煤泥的回收能力逐渐增强。通过该项目研究对于达到降低浮选过程能耗、提高煤泥浮选效率、丰富多流态分选过程理论研究体系具有重要意义。

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