Çimento Öğütme Uygulamalarında Bilya ve Malzeme Özelliklerinin Bilya Aşınma Sonuçları Üzerindeki Etkilerinin İncelenmesi
Özet
Within the context of the study, the wear of media in dry grinding environment was investigated for high chromium cast iron grinding balls by conducting the laboratory scale experiments with the ball mills. The study aimed at developing a dry test method to compare wear resistance in different types of the grinding media, and to comment on the media wear properties before using it in the industry. Laboratory scale tests are relatively less labor intensive and may enable accurate assessment of the media wear that occurs in industrial applications. Such a study is believed to be beneficial for both the media manufacturers and the dry grinding plants since there is a potential to reduce the costs associated with the wear with the proper media selection.
The influences of the characteristics of grinding balls together with the processed materials on media wear were considered in different experimental groups for cement grinding applications where dry grinding prevails. Throughout the thesis study, 35 different test conditions were adjusted where the influences of the grinding
media properties, the type of the milled material, material filling inside the ball mill, the type of the milled product and the effects of mill diameter on media wear were discussed.
The results obtained in the grinding and tumbling tests were evaluated in relation with the microstructure properties of the grinding balls. The evaluations indicated that increasing the volumetric fractions of the carbides in the microstructure increases the resistance to wear. It was also observed that the amount of the wear increased with the increase in the work indices of the milled materials. In addition, it was found that increasing material filling ratio caused a decrease in the wear of the grinding balls. The mill diameter was found to be an influencing parameter on the wear results and proved that increasing mill diameter cause an increased wear in all six types of grinding media. One of the major outcomes of the study was; independent of the mill diameter and the work indices of the milled material, the measured media wear from the highest to the lowest was in the same order.
The wear data of the grinding balls obtained from the laboratory tests was then compared with the industrial scale grinding ball wear to investigate the correlations. As a result of the comparison, it was understood that it is possible to predict the wear performance of the grinding media from the laboratory scale tests before their industrial use. However the expansion of the data base is recommended as a future study for having improved correlation and predicting capabilities.
The data obtained as a result of the experimental studies coincides with the information reported in the literature where the influences of chemical composition, microstructure properties and wear resistance of the grinding balls were discussed. It is considered useful to incorporate the test method in the quality control process of cement grinding facilities in order to evaluate the effect of the ball and material properties on grinding media wear.
