Structure And Size Optimization Of A Vertical Mill’s Stirrer

Mineral grinding is the most energy-consuming process in the mineral separation process.Its efficiency are directly related to the economic benefits of the enterprise.Since it has been found that the stirred mill has more advantages than the traditional ball mill in the field of fine grinding,stirred mill is becoming widely used in grinding mineral.Due to the late development of the stirred mill,there is still no complete design theory in designing it.Therefore,the research on how to improve the grinding performance of the stirred mill has become a hot topic.Studies in a literature shows that using ceramic balls as grinding media is more energy efficient than using steel balls under the premise of ensuring the same product quality.In fact,its related simulation and experiment are conducted in laboratory stirred mill,when the results are applied to the industrial production mill,the grinding performance is not satisfied.So it is necessary to make deep study on how to further improve the comprehensive performance of the vertical stirred mill.As the most important energy input component of the mill,the agitator,was always designed by experience,which makes the performance of the mill hard to be guaranteed.Therefore,this paper directly targets the industrial vertical mill with cylinder height and diameter of 4285mm and 3000mm respectively,and uses CFD(Fluent as solver)simulation method to optimize the structure and size of the stirrer.The specific contents of this paper can be summarized as follows:(1)Based on the vertical mill’s pressure distribution function,the mathematical expressions of the load torque of the screw,disc and pin stirrer are derived.And this is used for providing support to the following simulation verification and mill’s power draw calculation.(2)Based on the experimental mill,the corresponding simulation model is established.By comparing the simulation results with the previous experimental conclusions and the theoretical derivation conclusions of this paper,the feasibility of the simulation method is proved in many aspects.(3)The structure of screw,disc and pin stirrer of industrial vertical mill is optimized by using mill power,grinding strength and mixing effect as indicators.(4)Using the orthogonal and Box-Behnken simulation design method,the optimal sizes of these stirrers are obtained based on the optimal stirrer structure in the previous step.(5)Similarity theory is used to reduce the size of the optimized large-scale mill’s agitator,and the optimized screw stirrer is comparied with the original experimental type to verify the reliability of the optimization results.In addition,static and modal analysis of the stirrer are carried out by fluid-structure coupling method.