Research On Two-Stage High-Intensity Flotation Process And Equipment Technology

In the context of industrial intelligence,the development and innovation of equipment for the mining industry are key links for moving towards intelligence,green and unmanned production.Due to the decreasing ore grade and the accelerating pace of intelligent construction,there are limitations in the design and equipment structure of the flotation process.In conventional flotation processes,particle-bubble mineralization and separation of mineralized bubbles occur within a single device space,such as flotation machines or columns.There exist complex coupling relationships and interactions among different sub-processes,which pose many difficulties for precise measurement and control of the flotation process.Therefore,developing an efficient,controllable,and modular flotation equipment is of great significance to improve its performance and efficiency.This article introduces a design concept of enhancing the flotation process by redefining its structure,and a two-stage high-intensity flotation equipment was developed through flow field simulation calculation.The FLUENT finite element analysis software and EDEM discrete element analysis software were used to conduct comprehensive simulation calculations on the flow field within the forced mineralizing device and separation device,focusing on exploring the movement laws of fluids under different fluid mechanics conditions.Numerical simulation methods were adopted to optimize the structural parameters,providing a theoretical basis for the development of efficient flotation equipment.The paper first designed a forced mineralizing device with a volume of 3 L and a separation device with a volume of 50 L.Based on the two-stage high-intensity flotation process,a flotation system was built in the laboratory,which realized the separation of particle-bubble mineralization process and mineralized bubbles from the slurry by setting the two sub-processes in isolated spaces.The fluid mechanics conditions of each sub-process can be optimized and measured accurately.The flow field characteristics and particle motion in the forced mineralization device were analyzed by simulation,and the effects of different impeller rotational speeds and inflation volumes on the hydrostatic pressure,velocity,turbulence intensity,vortex structure and gas content were investigated,as well as the bubble size distribution and particle residence time.It was found that the flotation process could achieve high intensity mineralization at impeller speed between 1500-1800 rpm.The bubble distribution varied at different speeds,and the number density of bubbles with particle size below 1 mm increased with the increase of speed.The average residence time of coal slurry particles at 1500 rpm is about 4.10 s,which is beneficial for the improvement of flotation efficiency.The above findings provide basic data and directional guidance for the optimization of the structure of the forced mineralization unit and the selection of operating parameters.Simulation analysis of the internal flow field characteristics and particle motion of the separation unit was carried out,mainly including the influence of factors such as aeration volume,overflow bottom flow distribution rate on fluid static pressure,velocity,turbulence intensity,vortex structure and gas content,as well as the residence time and motion characteristics of the mineralized bubbles.It was found that the separation device has obvious gas-liquid separation,which can effectively avoid the tailing flotation phenomenon.When the reverse fluidized water volume is 0.48 cm³/cm²·s,the residence time of mineralized bubbles in the separation device is the shortest,which is about 10.77 s.This is conducive to improving the flotation efficiency and can meet the demand for rapid separation of mineralized bubbles.At the same time,for the tilted channel of the separation device,the mechanism is analyzed by the state of force on the particles and the velocity and direction of motion,and the formula for calculating the diameter of the particles in the tilted channel is derived to determine the direction of motion of the bubbles.To provide basic data and directional guidance for the optimization of the working conditions of the separation device and the selection of the operating parameters.Using clear water and air as the medium,the flow and distribution law of gas-liquid two-phase is studied in depth.By defining the calculation equations of overflow distribution rate,foam holding capacity,positive and negative bias flow dividing point,the change law of operating parameters on the influence of overflow and bottom flow of gas-liquid two-phase experiment is examined.The bottom flow outlet height,water inlet,bubbling agent concentration and reverse fluidization water had significant effects on the overflow distribution rate,and the factors interacted with each other,and the regression equation between the overflow distribution rate and each factor was derived.The size of bubbles and mineralized bubbles was measured using a Pixact bubble particle monitoring instrument,and the average diameter of Sauter d₃₂,was the smallest at 295μm when the speed reached 1500 rpm.It was also found that the mineralized bubbles tended to adhere together and form air flocs,which positively contributed to both bubble and mineral particle collision and attachment.This paper systematically studied the influence of gas infusion rates and reverse fluidization water quantity on the particle separation efficiency of coal slurry.The flotation results obtained a product with a clean coal ash content of 5%and a tailings ash content greater than 70%,demonstrating that the flotation system has higher separation accuracy than conventional flotation and achieves fast and high-precision separation of coal slurry.The concept of ore dressing information entropy was proposed,which characterizes the multiple dependencies of particle properties（such as particle size and density）to evaluate the separation process of concentrate and tailings.This is of great significance for studying the distribution patterns of coal slurry particles.