基于高速动态显微测试的旋流矿化特征研究

发布时间：2018-02-05 21:29

本文关键词： 颗粒三维运动轨迹相互作用颗粒停留时间　出处：《中国矿业大学》2016年硕士论文　论文类型：学位论文

【摘要】：由于旋流流场复杂多变,微观过程难以观察,对于旋流流场气泡矿化的微观机理研究基本都建立在定性理论基础之上,而研究气泡与颗粒在旋流流场中的运动特征对于分析旋流矿化特征具有一定意义。利用浮选柱旋流试验平台和两台垂直布置的高速动态摄像机,构建高速动态测试系统,并采用该系统记录浮选柱旋流流场中单气泡、单颗粒的运动过程。利用ProAnalyst高速运动分析软件,对浮选柱三维系统进行相应坐标系的定义,并通过对所采集的视频进行轨迹追踪,获得其三维坐标,从而对单气泡、单颗粒的运动特征以及气泡与颗粒相互作用的矿化特征进行研究。对单气泡、单颗粒进行旋流运动特征测试,获得了其不同条件下稳定的三维运动轨迹,结果表明:运动过程中,气泡更靠近浮选柱旋流装置中心轴,而颗粒更靠近边壁;随着循环流量的增大,单气泡的轴向升浮速度减小,运动总速度增大,最大运动半径增大;随着气泡尺寸的增大,单气泡的轴向升浮速度减小,运动总速度减小,最大运动半径增大;随着循环流量的增大、颗粒尺寸与密度的减小,单颗粒的最大轴向升浮高度增大,轴向升浮速度增大,旋流流场中的颗粒停留时间增大。根据单气泡、单颗粒的旋流运动特征,从旋流流场中颗粒停留时间的角度对气泡矿化特征进行分析,结果表明:大循环流量、小尺寸和小密度颗粒以及小尺寸气泡有利于旋流矿化的发生;在旋流锥段上方加设筛板装置可以使气泡充分弥散在浮选柱中心轴至边壁整个横截面上,极大地增大旋流流场中气泡矿化的概率。通过高速动态显微测试系统跟踪浮选柱旋流流场中气泡与颗粒间的碰撞、粘附过程,可以直观地观测到气泡矿化的过程,结果表明:颗粒在接近气泡时,会趋向于气泡的运动方式,最终突破水化膜,与气泡发生碰撞、粘附;发生矿化的气泡与颗粒在运动过程中基本呈同向运动,并切向相遇、碰撞、粘附,这种矿化方式属于剪切矿化。颗粒粘附到气泡上之后,随气泡的运动在气泡表面滑动,并寻找气泡最尾端以求稳定。
[Abstract]:Because the swirl flow field is complex and changeable, the microscopic process is difficult to observe, and the microscopic mechanism of bubble mineralization in swirl flow field is basically based on qualitative theory. The study of the motion characteristics of bubbles and particles in the swirl flow field is of certain significance for the analysis of the characteristics of swirl mineralization. The floatation column swirl test platform and two high-speed dynamic cameras with vertical arrangement are used. A high speed dynamic measuring system was constructed, and the motion process of single bubble and single particle in the cyclone flow field of flotation column was recorded by the system. ProAnalyst software was used to analyze the high speed motion. The three dimensional system of flotation column is defined in the corresponding coordinate system, and the single bubble is obtained by tracking the track of the collected video. The motion characteristics of single particles and the mineralization characteristics of the interaction between bubbles and particles were studied. The characteristics of swirl motion of single bubble and single particle were measured and the stable three-dimensional motion trajectory was obtained under different conditions. The results show that the bubbles are closer to the central axis of the flotation column swirl device and the particles are closer to the side wall during the moving process. With the increase of circulating flow rate, the axial buoyancy velocity of single bubble decreases, the total velocity of movement increases, and the maximum moving radius increases. With the increase of bubble size, the axial buoyancy velocity of single bubble decreases, the total velocity of movement decreases, and the maximum moving radius increases. With the increase of circulating flow rate, the particle size and density decrease, the maximum axial floating height of single particle increases, the axial floating velocity increases, and the residence time of particles in the swirl flow field increases. From the point of view of residence time of particles in the swirl flow field, the characteristics of bubble mineralization are analyzed. The results show that: large circulation flow rate. Small size, small density particles and small size bubbles are conducive to the occurrence of swirl mineralization. By adding sieve plate over the swirl cone section, the bubble can be dispersed in the whole cross section from the center axis to the side wall of the flotation column. The probability of bubble mineralization in the swirl flow field is greatly increased. The collision and adhesion process between bubbles and particles in the swirling flow field of flotation column is tracked by a high speed dynamic microscopic testing system. The process of bubble mineralization can be observed intuitively. The results show that when the particle is close to the bubble, it will tend to move the bubble, finally break through the hydration film, collide with and adhere to the bubble; The mineralized bubbles and particles basically move in the same direction in the process of movement, and tangential encounter, collision, adhesion, this type of mineralization belongs to shear mineralization. The particles adhere to the bubble after. With the movement of the bubble, it glides on the surface of the bubble and finds the most end of the bubble for stability.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD923

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