粉煤灰摩擦电选颗粒的分选行为及高效脱炭研究

A theoretical foundation of design and control for high voltage electric field is obtained according to the effect of separation behaviors on the removal unburnt carbon process. Behaviors of charged particles include of motion, charge transfer, capture, transfer and distribution. The foundation can guide and realize the high efficiency of fly ash triboelectrostatic beneficiation. .At first, the movement behavior and charge transfer rule of carbon and ash particles in the high voltage electric field are investigated with the discrete element numerical simulation and mathematical modeling method. A mathematical model of particle surface charge transfer is established. Then, the influence of motion and charge transfer on the removal unburnt carbon was investigated. Secondly, the capture mechanism of carbon and ash particles is analyzed by using the finite element analysis and the dynamic experiments. A technical solution of efficient capture is obtained. Elements content and particle size distribution of products is tested by plasma mass spectroscopy, X-ray diffraction and laser particle size instrument, respectively. The geometrical shape and microstructure are analyzed by scanning electron microscopy and Raman spectrum. The transfer rule and distribution mechanism are revealed and then effect of capture, transfer and distribution on the removal unburnt carbon was researched. Finally, the theoretical foundation of design and control for high voltage electric field is obtained according to the investigation on the influence of separation behaviors on the removal unburnt carbon. It will be verified by the experiments of different coal fly ash. The high efficiency of fly ash triboelectrostatic beneficiation is realized.

通过研究粉煤灰摩擦电选中颗粒的运动、电荷转移、捕获和迁移分配等分选行为对脱炭的影响机制，获得了分选电场设计和调控的理论依据，指导并实现粉煤灰摩擦电选高效脱炭。. 首先，借助离散元数值模拟和数学建模方法，揭示碰撞接触作用下带电炭、灰颗粒在高压电场中的运动行为特征、电荷转移与传递规律，建立颗粒表面电荷转移数学模型，研究运动行为和电荷转移行为对脱炭的影响机制。其次，运用有限元分析和高速动态实验手段，揭示了带电炭、灰颗粒在电场中的捕获机理，获得高效捕获的技术方案；应用等离子体质谱、X衍射和激光粒度仪检测产物元素含量和粒度分布，应用扫描电镜和拉曼光谱分析产物赋存形态和微观形貌，揭示粉煤灰中多组分的迁移规律与分配机制，研究捕获行为、迁移分配行为对脱炭的影响机制。最后，通过研究分选行为对脱炭的影响机制，获得分选电场设计和调控的理论依据，经不同粉煤灰的实验验证，实现粉煤灰摩擦电选高效脱炭。

作为典型的煤基固废，粉煤灰资源化利用受到高度关注，而脱炭是需要解决的首要问题，项目运用摩擦电选技术实现粉煤灰脱炭。主要研究粉煤灰摩擦电选中颗粒的运动特征、电荷转移、捕获和迁移分配等分选行为对脱炭的影响机制，获得了分选电场设计和调控的理论依据，实现了粉煤灰摩擦电选高效脱炭。通过研究揭示了炭灰颗粒碰撞荷电、运动偏转、电荷转移等微观机理，提出了强化荷电、运动干预、降低电荷转移的方法；从微观角度掌握了颗粒电场迁移规律与分配机制，开发了新型非线性电场结构，提高了炭灰颗粒的捕获效率，实现了炭灰颗粒电场中的迁移分配干预控制；最后，通过研究分选行为对脱炭的影响机制，获得了分选电场设计和调控的理论依据，构建了高效脱炭的调控方法，在6个不同地区粉煤灰样品电选脱炭实验中得以验证，实现了粉煤灰摩擦电选高效脱炭，为下一步工程技术开发与实践奠定了理论基础。