Numerical Study Of Multi-Phase Flow Characteristic And Flotation Dynamics Performance In Flotation Machine

Large-scale pneumatic-mechanical flotation machine is used widely in the mineral process for its higher handling capacity and lower unit power loss. The design methods of large-scale flotation cell still stays at the stage of structure-similitude design methods which usually refer to the small-scale floatation structure. The effective design method based on hydrodynamics similitude has not come into being. The flotation processes involves many physical processes. However pulp-bubbles-flotation reagent multiphase turbulent flow is the basic processes. The solid-liquid-gas three-phase fluid dynamics characters determine the flotation dynamics performance of flotation.The relationships between operation parameters, fluid dynamics parameters and flotation dynamics parameters are been explored in order to provide some references for the optimization design and operation of pneumatic-mechanical flotation.The inner multiphase flow characters and flotation dynamics parameters of JFC-150 large-scale pneumatic-mechanical flotation are investigated as follows:1. The effect of froth zone on the flow fields of flotation is omitted according to analysis of structure characters and flow field characters. The flow field is simplified and divided into three zones as mixture zone, transportation zone, and separation zone.2. The influent factor of the flotation reagent is omitted for the flow model simplification. The Mixture multiphase flow model and RNG K-ωturbulent mode are used to simulate the flow fields in the flotation. The simulation results of the flow fields in a small-scale flotation are compared with the PDA test results, which shows the feasibility on the multiphase turbulent flow model used to simulate the flow fields of flotation.3. Based on the model, numerical simulation on gas-sold-liquid three-phase flow in the JFC-150 flotation with different rotation speeds and charge pressure are given. The effects of rotation speed of impeller and charge pressure on the solid-liquid-gas multiphase turbulent flow characters and flotation dynamics parameters are analyzed.4. Based on the consideration of pulse concentration and the mathematical model of resident time distribution (RTD), the numerical simulation method on the RTD is given. The simulation initializes from the steady single-phase flow fields. The effects of rotation speed of impeller on the RTD of pulp are analyzed.5. The optimization design of the JFC-150 flotation by the simulation tests based on the inner flow analysis is given. The industrial test results show the improvement of flotation performances which indicate the success of structure optimization and the validity and reliability of numerical prediction method for pneumatic-mechanical flotation performance.The innovations of the paper are listed as follows:1. The method of numerical simulation on the solid-liquid-gas three-phase flow in the pneumatic-mechanical flotation machine is proposed.2. The model and prediction method on the RTD of mineral pulp are given.3. Based on the analysis of solid-liquid-gas three-phase flow characters, the relationships of the operation parameters as impeller rotation speed and charge pressure with the flotation dynamics parameters as void rate, air-dispersion degree, bubbles surface area flux, power intensity and RTD et al are built.