浮选机流场模拟及矿浆流体动力学研究

发布时间：2018-07-03 02:13

本文选题：浮选机 + 数值模拟　；参考：《江西理工大学》2017年硕士论文

【摘要】：目前浮选是矿物分选的主要手段之一。浮选机是浮选工作中的核心机械,矿物分选过程在浮选机内部进行。研究浮选机工作参数、浮选机内部浮选动力学参数及浮选指标三者之间的关系有助于提高矿物分选效率优化浮选指标。本文通过数值模拟的手段,对XFD-II 1.0L浮选机内部流场进行了适当的简化,提出Eulerian多相流模型和标准k-ε湍流模型对浮选机内部流场进行模拟。考察了五种叶轮转速和五种充气量下的单相流模型、气液两相流模型及固液两相流模型的流场特性,探索了叶轮转速、充气量等工作参数与矿浆含气量、空气分散率等浮选动力学参数的关系,并通过空气分散率测定验证了数值模拟结果。主要研究工作与结论如下:(1)根据XFD-II 1.0L型机械搅拌式浮选机内部流场特点及多相流特征,忽略泡沫层对流场的影响,对浮选机内部流场进行了简化,对流域的搅拌混合区、矿物输运区、脉石分离区流场特性进行了研究。(2)考察了叶轮转速500r/min、1000r/min、1500r/min、1900r/min、2400r/min五个值下搅拌混合区、矿物输运区、脉石分离区及浮选槽底部在单相流模型及气液两相流中矿浆流的速度分布特性,发现流场各区域速度随叶轮转速升高而增大。(3)考察了充气量50L/h、100L/h、150L/h、200L/h、250L/h下各叶轮转速下浮选槽底部和矿浆自由液面附近矿浆含气量和空气分散率的变化。自由液面矿浆含气量随叶轮充气量增大而增大,空气分散率随充气量增大在开始阶段保持较高水平并缓慢降低,当充气量增大到某一临界点后空气分散率迅速降低,并且这一临界点随叶轮转速的上升高逐渐增大。(4)在综合考虑矿浆含气量和空气分散率的情况下得出XFD-II 1.0 L型浮选机合适的工作参数为叶轮转速1900r/min、充气量为250L/h。经过实验室浮选试验验证数值模拟结果选定的浮选机工作参数合理,具有工程实际应用的意义。(5)考察不同工作参数下白钨矿、萤石和方解石三种矿物在浮选槽底部和矿浆自由液面附近的含量。经分析1700r/min至1900r/min目的矿物白钨矿相对另外两种矿物在浮选槽上部输运区及分离区含量较高。经过实验室白钨矿纯矿物浮选试验验证,白钨矿在矿浆上部的数值模拟结果含量与实际浮选白钨矿回收率成正比。并确定了适宜白钨矿与脉石矿物方解石、萤石的分离最佳条件是叶轮转速1900r/min,充气量250L/h。
[Abstract]:At present, flotation is one of the main means of mineral separation. Flotation machine is the core machinery in flotation, and mineral separation process is carried out inside flotation machine. The study on the working parameters of flotation machine, the relationship between flotation kinetic parameters and flotation index in flotation machine is helpful to improve the separation efficiency of mineral and optimize the flotation index. In this paper, the internal flow field of XFD-II 1.0L flotation machine is simplified by numerical simulation. Eulerian multiphase flow model and standard k- 蔚 turbulence model are proposed to simulate the flow field in XFD-II 1.0L flotation machine. The flow field characteristics of single-phase flow model, gas-liquid two-phase flow model and solid-liquid two-phase flow model under five kinds of impeller speed and five kinds of aeration were investigated, and the working parameters such as impeller speed, gas volume and slurry gas content were explored. The relationship between the flotation kinetic parameters such as air dispersion and so on, and the numerical simulation results were verified by air dispersion measurement. The main research work and conclusions are as follows: (1) according to the characteristics of internal flow field and multiphase flow in XFD-II 1.0L mechanical flotation machine, the flow field of flotation machine is simplified and the mixing zone of basin is simplified. The characteristics of flow field in mineral transport area and gangue separation region were studied. (2) the impeller speed of 500rr / min ~ 1000r / min ~ 1 500 r / min ~ 1 900 r / min = 1 900 r / min ~ 2400r / min mixing zone, mineral transport area, The velocity distribution characteristics of slurry flow in single phase flow model and gas-liquid two-phase flow in gangue separation zone and bottom of flotation cell. It is found that the regional velocity of the flow field increases with the increase of the impeller speed. (3) the gas content and air dispersion of slurry at the bottom of the flotation cell and near the free liquid surface of the slurry at the speed of each impeller are investigated. The air content of free liquid level slurry increases with the increase of impeller air volume, and the air dispersion rate keeps a high level at the beginning and decreases slowly with the increase of air volume, and decreases rapidly when the air volume increases to a certain critical point. And this critical point increases gradually with the increase of impeller speed. (4) considering the air content and air dispersion of pulp, the suitable working parameters of XFD-II 1.0 L flotation machine are impeller speed 1900 r / min and aeration volume 250 L / h. Through the laboratory flotation test, it is proved that the working parameters of the flotation machine selected by the numerical simulation results are reasonable and have the significance of engineering practical application. (5) Scheelite under different working parameters is investigated. The contents of fluorite and calcite in the bottom of flotation cell and near the free liquid level of pulp. The content of scheelite from 1700r/min to 1900r/min is higher than the other two minerals in the upper transport area and separation zone of flotation cell. The results of laboratory flotation tests show that the content of scheelite in the upper part of the slurry is directly proportional to the actual recovery rate of wolframite flotation. The optimum conditions for separation of fluorite from scheelite and gangue mineral calcite are as follows: impeller rotation speed 1900 r / min, aeration volume 250 L / h.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD456

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