A new approach for the testing method of coal grindability

In this study, a total of 26 hard coal sample (either clean or original) from Zonguldak Coal Basin (17 from Zonguldak, 9 from Amasra) and a total of 17 low grade Turkish coals from various locations in Turkey were collected. So, a total of 69 samples were analyzed initially with standard method of coal grindability, i.e. HGI values were determined. In addition, an alternative method (does not require a standard HGI mill) for grindability measurement was proposed in this study. The abovementioned alternative method includes a ring mill with specified conditions and Malvern Mastersizer. As regards to the procedure of the new proposed method for the determination of coal grindability, samples were prepared in the size range of -1.7 + 1.18 mm size group and they were ground in ring mill. Here, ring mill was chosen because of the fact that it is very widely used for sample preparation and it is very commonly available in every laboratory. Procedure proposed includes placing abovementioned specified samples in ring mill (See Material and Method) and having the samples ground in a previously determined time period. After this grinding process (with ring mill) they have rather different size distribution at the end depending on their nature of grindability. For better understanding, having the ground samples of (-1.7 + 1.18 size group for 20 s for 50 g samples) and analyzing their size distributions with Malvern Mastersizer, ground samples have different D10, D50, D90, D32 and D43 at the end. Comparing these size parameter results with previously determined HGI values, it can be claimed that coal grindability can be easily determined with this method, since evaluated HGI values with the method proposed are ±0.05% different than the determined HGI values. © 2019 The Society of Powder Technology JapanBritish Association for PsychopharmacologyAuthor of this study would like to thank to coal producer companies for providing samples, and would like to specially thank to professors (Sait Kizgut, İhsan Toroglu, Dilek Cuhadaroglu), researchers (Baris Akkaya, Mehmet Bilen) and M.Sc. students (Erman Kıran, Cemil Emre Yilmaz and Alper Oktem) of Mineral Processing Division of Mining Engineering Department of Zonguldak Bülent Ecevit University. Their contribution on this paper is highly appreciated. Authors also would like to express their appreciation to the BAP Research Coordinatorship of Bülent Ecevit University financial support, and coordinatorship staff