Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 6Citation - Scopus: 7Size Reduction Characterization of Underground Mine Tailings: A Case Study on Sandstones(Springer, 2020-06-09) Koken, EkinThe production of construction and building materials starts with reducing the size of natural, industrial, and waste materials. In addition to strength and durability considerations of natural resources recommended by various institutions, size reduction characterization, specific to rock aggregates, has a vital role in their size-related quality. In this study, various sandstones extracted from underground mines located in northwestern Turkey were investigated for size reduction characterizations. Several mineralogical, textural, and physico-mechanical properties were determined for each rock type. Crushability tests were carried out using a laboratory-scale cone crusher for different feeding size fractions, namely + 11.20 - 16.00 mm (size I), + 9.52 - 16.00 mm (size II), and + 6.30 - 16.00 mm (size III). Based on the crushability tests, crushed particles were analyzed, focusing on production yield, size, and shape properties. Each crushability test was also explored for energy consumption arising from varying rock properties of the sandstones. The laboratory test results demonstrated that the degree of rock crushability (DRC) and specific energy consumption (E-cs, kJ/kg) were associated with the Brazilian tensile strength (BTS, MPa) and apparent porosity (n(e), %) of the sandstones. The results also showed that the degree of sorting in mineral constituents, quantified as the sorting coefficient (S-c), affected the DRC. However, mineralogical features of the sandstones have no significant impact on DRC andE(cs). Variations in feeding gradation, irrespective of whether mineralogical, textural, or physico-mechanical properties, have remarkable effects on product flakiness and yields for specific size fractions. In light of the findings obtained, the present study provides knowledge on how the sandstones behave under cone crushing operations.Article Citation - WoS: 12Citation - Scopus: 16Evaluation of Size Reduction Process for Rock Aggregates in Cone Crusher(Springer Heidelberg, 2020-06-04) Koken, EkinThe size reduction process of rocks in cone crushers is one of the most important issues, particularly for the secondary and tertiary stages of crushing operations. In this study, 17 different rock types were considered for the evaluation of their size reduction variations that occurred in a laboratory-scale cone crusher. Based on several mineralogical, physico-mechanical, and aggregate properties determined for each rock type, the crushability tests were performed. Before and after the crushability tests, particle size distribution (PSD) of the uncrushed (feed) and crushed (product) materials were determined by sieve analyses. On the basis of these PSDs, the degree of rock crushability (DRC) was attempted to quantify by simple approaches (i.e., size reduction ratio, SRR, and the theoretical square mesh aperture size that corresponds to the 10% of the cumulative undersize in the product, P-10 (mm)). The crushability test results demonstrated that the DRC in cone crusher could be quantified by focusing on the variations in the SRR and P-10. The SRR and P-10 are associated with three important rock properties, Shore hardness (SH), Los Angeles abrasion loss (LAA, %), and Brazilian tensile strength (BTS, MPa). The textural and mineralogical features of rocks also have substantial impacts on the DRC for several rock types. It was concluded that the combination of the SRR and P-10 could be considered together for the evaluation of DRC in cone crushers. Moreover, further research potentials on the DRC were also discussed in this study.Conference Object Citation - Scopus: 2Comparison of Secondary Crushing Operations Through Cone and Horizontal Shaft Impact Crushers(International Multidisciplinary Scientific Geoconference, 2020-09-20) Köken, E.; Qu, JiliIndustrial size reduction processes such as crushing and grinding play vital roles in rock quarrying. The present study states real field data concerning secondary crushing operations through the cone and horizontal shaft impact (HSI) crushers. In this regard, a total of 44 case studies were collected from several rock quarries located in various parts of the world. Based on the field data, crushing performances of the cone and HSI crushers were compared by statistical analyses. The statistical analyses demonstrated that the specific energy consumption of HSI type crushers is relatively higher than those of cone crushers when comparing their production capacities. However, the difference in the specific energy consumption decreases with increasing the Los Angeles abrasion loss (LAA) of rocks. Specifically, the difference closes remarkably up when the LAA approaches 40%. It was also achieved that there is no remarkable superiority over the crushers with a specific energy consumption lower than 0.75 kWh/ton. Furthermore, the maximum feed size for cone and HSI crushers could be estimated at 12% of the mainframe opening and 39% of the rotor diameter, respectively. The ratios statistically found could be declared a start-up. These ratios are, therefore, beneficial for initial sizing related to secondary crushing operations. It was also claimed that for higher achievements in the production capacity (e.g.,> 8000 ton/day), cone crushers could be more feasible for handling rocks whose LAA is lower than 30%. Otherwise, the selection of secondary crushing equipment is associated with rock lithology, its reserve, economic constraints, targets, and marketplaces of rock aggregate manufacturers. © 2021 Elsevier B.V., All rights reserved.