露天矿大高差溜槽运输粉尘析出机理与逸散规律研究

Abandoned pit of governance has been a worldwide difficult problem, is the current mine environment to fix the problem to be solved in our country. Mine backfill is the ideal way of abandoned open pit management, chute is one of the best mode of transportation in the mine backfill, however large elevation difference chute transportation of dust pollution is a big bottleneck of popularization and application of the chute. Based on gas-solid two-phase flow theory, analyze the chute channel and movement characteristics of dust particles and gas coupling, clarify multi-factor coupling mechanism of dust under the action of large elevation difference chute. Based on particle swarm movement theory and aerosol dynamics theory, combining with the dust particle characteristics, the numerical simulation and similar experimental methods, research in the chute induced wind speed, size, flow, chute section, factors such as length, Angle and dust, the relationship between the diffusion of the dust particles collide with the wall of the role, the mining area of meteorological factors on the effect of dust concentration distribution, revealing the elevation difference chute transportation system of large open-pit mine dust from law and concentration distribution characteristics. Research results will provide the chute and dust prevention and dust control measures for the rational design of the choice of design to provide theoretical basis and application of large elevation difference chute, to solve the waste pit backfilling technology design, implementation of mine reclamation, the improvement of the ecological geological environment has important practical significance and theoretical value.

废弃露天矿坑的治理一直是世界性的难题，更是目前我国亟待解决的矿山环境修复关键问题。矿坑回填是废弃露天矿坑治理的理想方式，溜槽是矿坑回填最佳运输方式之一。大高差溜槽运输产生的粉尘污染是溜槽回填技术推广应用的瓶颈。基于气固两相流理论，分析溜槽通道内粉尘颗粒与气体耦合的运动特性，阐明多因素耦合作用下大高差溜槽粉尘的产生机理。基于颗粒群运动理论和气溶胶动力学理论，结合粉尘颗粒特性，采用数值模拟和相似实验方法，研究溜槽内诱导风速、粒径、流量、溜槽断面、长度、倾角等因素与粉尘扩散之间的关系，研究粉尘颗粒与壁面的碰撞作用，及矿区气象因素对粉尘浓度分布的作用，揭示露天矿大高差溜槽运输系统粉尘逸散规律和浓度分布特征。研究成果将为溜槽的合理设计以及防尘、控尘措施的选择设计提供理论基础，实现大高差溜槽的推广应用，对解决我国废弃露天矿坑回填工艺设计、实现矿山复垦、改善生态地质环境具有重要的现实意义和理论价值。

废弃露天矿坑的治理一直是世界性的难题，更是目前我国亟待解决的矿山环境修复关键问题。矿坑回填是废弃露天矿坑治理的理想方式，溜槽是矿坑回填最佳运输方式之一。大高差溜槽运输产生的粉尘污染是溜槽回填技术推广应用的瓶颈。基于气固两相流理论，分析溜槽通道内粉尘颗粒与气体耦合的运动特性，提出溜槽运输系统转载点粉尘的析出是诱导空气的尘化作用、剪切压缩尘化作用和综合尘化作用的结果。基于颗粒群运动理论和气溶胶动力学理论，结合粉尘颗粒特性，采用数值模拟和相似实验方法，研究溜槽内诱导风速、粒径、流量、溜槽断面、长度、倾角等影响因素与粉尘扩散之间的关系。结果表明，粉尘质量浓度随物料粉岩质量分数、溜槽倾角增大而逐渐增大，随含水率增大而逐渐降低，确定了溜槽运输过程中产生的粉尘颗粒粒径范围在0～100µm之间；剪切气流速度2m/s时粉尘析出量很少，速度大于10m/s时粉尘的析出量逐渐增大；溜槽出口落差对粉尘的析出影响很大，落差为10m处粉尘的析出量明显比2m处大很多。溜槽越长物料运行时产生诱导气流和粉尘浓度越大；U形断面溜槽粉尘扬起高度和粉尘浓度明显小于矩形，建议采用U形断面的溜槽；正交试验表明，最优工艺条件为粉岩质量分数10%，含水率为 6.5% ，倾角为32°。因素对试验指标的影响主次顺序为含水率影响最大，其次是粉岩质量分数，溜槽倾角影响最小。诱导气流随着物料粉岩质量分数、溜槽溜放高度、物料质量流量的增大逐渐增大，随着含水率的增大，逐渐减小后趋于平稳；溜槽产生粉尘浓度随诱导气流成指数变化。因而，通过控制诱导气流的大小、粉尘颗粒粒径的分布、物料流速及溜槽出口落差减少溜槽系统粉尘的析出量。从溜槽整体粉尘浓度分布来看，溜槽粉尘质量浓度分布规律为溜槽底部粉尘产生量最大，中部次之，上方最小。溜槽底部为粉尘污染防治重点区域。研究成果将为溜槽的合理设计以及防尘、控尘措施的选择设计提供理论基础，实现大高差溜槽的推广应用。