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Study on the Impact of Rotation Speed Rate and Filling Rate to Grinding Effect

Author: RenHai
Tutor: DongWeiMin
School: Kunming University of Science and Technology
Course: Mechanical Design and Theory
Keywords: the movement law of media rotation speed rate filling rate power regression model
CLC: TD453
Type: Master's thesis
Year: 2011
Downloads: 103
Quote: 2
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Abstract

Ball mill is a key mineral processing equipment,and it is widely used in the chemical, cement, construction, ceramics and other industries.The equipment has the advantage of simple and compact structure, high reliability, but it also has a very prominent defects-high energy consumption and high iron loss. In order to improve the performance of ball mill, scholars of domestic and foreign have done a lot of research. As the work status of ball mill is affected by many factors including the mill speed rate, fill rate, ball to powder ratio, ball diameter, medium gradation etc, and those elements are coupled between each other, the theory of ball mill are no great breakthrough in a very long time.For these reasons, the law of the grinding mill is obtained from the way of experiment. According to the regulation of the ball mill to chose the operating parameters,the purposes of energy saving can achieve.Two significant factors which impact the work status of ball mill are selected-the mill speed rate and fill rate to study the grinding effect. On the one hand,the movement of the media mill theory is studied. On the basis of in-depth study of media law and the traditional method of ball mill calculation, a new usable power model of ball mill which considered the ball diameter and its cycle count is proposed. On the other hand,three different value of rotation speed rate and four different value of filling rate are selected to do whole combination experiments on aΦ600mm×400mm experimental prototype ball mill. Though the experiment, particle size and power consumption are obtained on the different rotation speed rate and different filling rate. Drawing size curves based on the results of screening to analysis the trends of grain size in the grinding process, and the mechanism of rotation speed rate and filling rate impact on the particle size is found. According to the regression models between these three factor,the extremum yield of product is predicted.In addition, specific energy consumption measured by the ball mill grinding efficiency, from the rotation speed rate, filling rate and grinding efficiency regression model, the theoretical minimum specific energy consumption is found.Experimental results show that the energy of ball carrying and the ball cycle count are two most important factors which affect the product size.When the rotation speed rate and filling rate were 0.83 and 0.52 respectively,the yield of fine-grained products arrived maximum;When the rotation speed rate and filling rate were 0.74 and 0.2 respectively,the yield of coarse-grained product obtained minimum;When the rotation speed rate and filling rate were 0.69and 0.33 respectively,the specific energy consumption achieved the lowest level.These results will provide a good reference to chose the working parameters of small and medium sized ball mill.

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