电磁周期式高梯度磁选机分选流场特性研究

发布时间：2018-06-02 20:30

本文选题：高岭土 + 周期式高梯度磁选机　；参考：《长沙矿冶研究院》2017年硕士论文

【摘要】：我国高岭土矿产资源面临着优质资源日益枯竭,同时杂质含量高、理化性质复杂的资源开发利用存在成本高、环境污染严重等问题。磁选法在当前高岭土提质降杂工艺中具有工艺简单、成本低、无污染等优点,而电磁周期式高梯度磁选机作为磁选法加工高岭土矿的核心装备,其可靠性、稳定性和经济性直接决定着绿色工艺在高岭土提质降杂工业的推广应用。但国产电磁周期式高梯度磁选机在工业化应用中仍存在一系列问题,因此,开展电磁周期式高梯度磁选机分选流场特性研究对查找问题根源、优化设备性能具有重要指导意义。针对电磁周期式高梯度磁选机分选流场特性分别开展了高岭土矿浆悬浮液性质分析、钢毛聚磁介质堆阻尼特性、实验室型电磁周期式高梯度磁选机分选流场仿真试验、影响分选流场分布特性的各因素分析及流场分布影响介质堆捕集弱磁性微粒的试验等研究内容。分选流场仿真试验研究及各影响因素分析:(1)矿浆悬浮液在聚磁介质堆中以轴向渗流为主,径向扩散为辅。(2)分选流场具有良好的对称性。(3)根据径向分速度的分布情况将介质堆从进料端至出料端划分为扩散区、过渡区、分选区、过渡区、聚集区。扩散区、聚集区径向分速度大,其中部与边缘渗流速度差异显著,中部渗流速度大、矿浆流量大,边缘渗流速度小、仅少量矿浆通过。过渡区径向分速度相对较小,中部区域与边缘区域渗流速度差异逐渐减小。分选区径向分速度几乎可以忽略,各区域基本保持在表观渗流速度。(4)各结构因素与操作因素对分选流场分布具有较大的影响作用,其中分别以分选罐的突扩、突缩比,矿浆的表观渗流速度最为显著,大突扩比及高表观渗流速度均不利于矿浆在介质堆中的均匀分布。介质堆捕集弱磁性微粒的试验验证了介质堆各区域矿浆渗流的流场分布规律,同时说明不同的渗流场对介质堆捕集弱磁性微粒具有显著的影响作用。分选罐突扩、突缩结构造成扩散区介质层捕集能力弱、集聚区易发生固体颗粒沉积现象。高表观渗流速度条件下介质堆有效捕集区域空间减小,且捕集能力下降。
[Abstract]:Kaolin mineral resources in China are faced with the problems of high cost and serious environmental pollution due to the depletion of high quality resources, high impurity content and complex physical and chemical properties. The magnetic separation method has the advantages of simple process, low cost, no pollution and so on. The electromagnetic periodic high gradient magnetic separator is the core equipment for processing kaolin ore by magnetic separation method, and its reliability. Stability and economy directly determine the application of green technology in kaolin industry. However, there are still a series of problems in the industrial application of domestic electromagnetic periodic high gradient magnetic separators. Therefore, it is of great significance to study the flow field characteristics of electromagnetic periodic high gradient magnetic separators to find out the root causes of the problems and to optimize the performance of the equipment. According to the separation field characteristics of electromagnetic periodic high gradient magnetic separator, the characteristics of kaolin slurry suspension, the damping characteristics of steel wool magnetic pile and the simulation test of separation flow field of laboratory electromagnetic periodic high gradient magnetic separator were carried out. The factors influencing the distribution of the separation flow field and the experiment of the medium heap trapping the weak magnetic particles are studied in this paper, and the analysis of the influence of the flow field distribution on the distribution characteristics of the separation flow field is also presented. Simulation study of separation flow field and analysis of influencing factors: 1) slurry suspension is mainly composed of axial percolation in magnetic agglomerate reactor. The separation flow field has good symmetry. 3) according to the distribution of radial velocity, the media stack is divided into diffusion zone, transition zone, sub-district, transition zone and accumulation area. In the diffusion area, the radial velocity of the concentrated area is large, the difference between the central seepage velocity and the edge seepage velocity is significant, the central percolation velocity is large, the slurry flow rate is large, the edge seepage velocity is small, only a small amount of slurry passes through. The radial velocity of the transition region is relatively small, and the difference of the velocity between the central region and the edge region is gradually decreasing. The radial velocity of the separation area is almost negligible, and each area is basically maintained at the apparent seepage velocity. (4) each structure factor and the operation factor have a great effect on the distribution of the separation flow field, among which, the ratio of sudden expansion and sudden contraction of the separation tank is respectively used. The apparent seepage velocity of slurry is the most obvious, and the large sudden expansion ratio and the high apparent seepage velocity are not conducive to the uniform distribution of slurry in the medium pile. The flow field distribution of slurry percolation in different regions of the medium reactor is verified by the experiments of collecting weak magnetic particles in the medium reactor, and it is shown that the different seepage fields have a significant effect on the capture of weak magnetic particles in the medium reactor. Because of the sudden expansion of the separation tank and the sudden contraction of the structure, the capture ability of the media layer in the diffusion zone is weak, and the accumulation area is prone to the phenomenon of solid particle deposition. Under the condition of high apparent percolation velocity, the space of the effective capture area of the media reactor decreases, and the trapping ability decreases.
【学位授予单位】：长沙矿冶研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD457

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