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ArticleName Oil shale breakage in a ball mill using different media types
DOI 10.17580/or.2021.04.04
ArticleAuthor Khairy N., El-Magd I. A., El-Mofty S. E., El-Midany A. A.

Cairo University (Giza, Egypt):

Khairy N., PhD Candidate;
El-Mofty S. E., Professor, PhD in Mining Engineering, Professor,
El-Midany A. A., Professor, PhD in Mining Engineering, Professor

National Authority for Remote Sensing and Space Sciences (Cairo, Egypt):

El-Magd I. A., Head of Department, PhD in Civil Engineering, Professor


Oil shale grinding critically affects subsequent upgrading processes. It may affect the surface properties, the structure of the ground material, or even both. It depends mainly on the type of the material under study; therefore, it needs to be treated carefully. In this study, the effect of ceramic and steel balls as grinding media on oil shale size reduction was studied in terms of ball filling, expressed as the number of balls, ball diameter, and grinding time, taking the mean size (d50) of the ground product as an indicator. Although the weight of ceramic balls is approximately two-thirds that of steel balls, the product size obtained with ceramic balls is twice the size produced using steel balls. The resulting d50 was 0.8 mm for steel and 1.8 mm for ceramic balls, when using 17 balls, 4 cm ball size, and 30 minutes grinding time, which confirms the effectiveness of the load applied to the particle bed by steel balls, as compared to ceramic balls. The results indicate that the smallest particle size was obtained at higher ball filling, with coarser balls, and longer grinding time due to the higher collision probability with higher loading by coarser balls. In addition, the experimental data showed a good fit to the first-order breakage law for both ball sizes used.
The authors gratefully thank the Minerals Technology and Testing Lab of the Faculty of Engineering, Cairo University, for providing the help, guidance, and the needed equipment and instrumentation for conducting the experiments for this work.

keywords Oil shale, grinding, kinetics, breakage rate, steel balls, ceramic balls

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