Hacifazlioglu H. | Samanli S. | Toroglu I.

Article | 2008 | Madencilik47 ( 4 ) , pp.23 - 34

This paper presents grindability of the Kokaksu (Zonguldak) bauxite crushed below -3.35 mm in a stirred mill. It was established that the operating parameters of the stirred mill such as the ball size, stirring time and the stirring speed have a considerable effect on the fineness of the product and these parameters are directly related to energy consumption. For grinding in a unit time, increasing the ball size yielded finer products and also increased the energy consumption. It was determined from the balls of various diameters tested that the optimal ball size for the feeding size was 6.5 mm. On the other hand, an increase in sti . . .rring time and stirring speed both yielded finer products and increased the energy consumption. To conclude, the yield of finer products by means of the stirred mill was established to be directly related to the energy consumed per unit time. In the last stage, the bauxite sample was ground in a conventional Bond mill and the grinding efficiency was compared with that of the stirred mill. It was established that the stirred mill is more advantageous in grinding fine particles (140 µm) in terms of energy consumption. However, for both size groups, the stirred mill was established to be advantageous in terms of grinding time. The stirred mill yielded products of a few micrometers in a few minutes Daha fazlası Daha az

Yilmaz S.

Article | 2019 | International Journal of Coal Preparation and Utilization , pp.23 - 34

In this study, a total of 26 samples (17 from Zonguldak and 9 from Amasra) were collected. In order to correctly understand the effect of coal cleaning process on grindability, samples were cleaned at 1.60 g/cm 3 ZnCl 2 solution and float samples were collected. Before and after this cleaning process, Hardgrove grindability indexes (HGI) of each coal samples (original and clean) were determined. Ash percentages show a decreasing trend by float and sink test for all samples studied as this was aimed and expected, while HGI showed an increase for Zonguldak coals and decrease for Amasra coals. However, total sulfur percentage decreases . . . for Zonguldak coals and either increases or decreases for Amasra coals, and change in total sulfur has the most significant role in terms of HGI change. Taking abovementioned variations into consideration, new approaches were proposed to predict HGI after cleaning. Proposed methods of HGI after cleaning yielded a correlation coefficient of 0.88, 0.82, and 0.86 (R 2  = 0.88, R 2  = 0.82, and R 2  = 0.86) respectively for first, second, and third methods, which can be regarded as highly significant. With these approaches, one can easily understand the effect of cleaning process on grindability. In addition, easiness in coal grindability with correct understanding of parameter contribution would be achieved. © 2019, © 2019 Taylor & Francis Group, LLC Daha fazlası Daha az

Bilen M. | Kızgut S. | Yilmaz S. | Baris K. | Cuhadaroglu D.

Article | 2018 | International Journal of Coal Preparation and Utilization38 ( 2 ) , pp.75 - 87

Grindability of a coal is generally represented in terms of the Hard Groove Grindability Index (HGI); a coal of lower HGI needs more energy to be ground. Samples of this study were taken from the Amasra coalfield of the Zonguldak Hard Coal Basin to determine if coal grindability varies with the burial depth of coals. Samples from different burial depths were analyzed and corresponding HGI values were obtained. HGI values of the original samples were found between 51.43 and 79.26. A float-and-sink analysis was performed for some of the original samples and it was found that the HGI values of floated coal samples change between 49.04 . . .and 73.52. A new method, which employs proximate and petrographic analysis data and the burial depth, was proposed for the prediction of HGI. Correlation of HGI with burial depth or the discrimination of floated and original coal currently exists. Correlations of the proposed methods have satisfactory coefficient of determination values (R2 =.75, R2 =.86) for the original and floated coal samples studied. This new proposed method was tested on the data and the previously studied original and floated coal samples of the Zonguldak coalfield and yielded a good correlation (R2 =.87, R2 =.90). The proposed method can be considered to yield reasonable predictions for the Amasra coalfield. © 2016 Taylor & Francis Daha fazlası Daha az

Bilen M. | Kizgut S. | Çiçikci E.

Conference Object | 2017 | IMCET 2017: New Trends in Mining - Proceedings of 25th International Mining Congress of Turkey , pp.438 - 442

In this study, Tincal samples from Bandirma Boron Plant were taken for the period of October 2015. Tincal samples from the feed stream were collected for a one-month period on daily basis. A total number of 31 samples were analyzed in terms of moisture content and B2O3 grade. Moisture content and grade of the run of mine ore have an effect on the recovery of the boron processing plant. Concentrate grade was also determined at the same period where feed samples were collected and a correlation was tried to be established. Recovery of the plant was calculated each day as assuming the daily feed amount of Tincal as 500 tonnes (monthly . . .15000 tonnes) and daily product of 200 tonnes (monthly 6000 tonnes). Feed Tincal moisture contents vary between 2.77% and 5.54%. Although this range of moisture content is not a big deal, it might be related with increase or decrease in recovery percentages. B2O3 grade of the feed ore varied between 22.67 % and 27.25%. This approximately 5% range could be meaningfull, an increase in feed grade would also cause an increase in product B2O3 grade as expected. In this study, feed moisture and feed grade was correlated with recovery and a new method to predict recovery is proposed. According to this new method, recovery of B2O3 would be easily calculated by just employing the moisture content and grade data of run of mine ore. Very high correlation coefficient (R2=0.99) between measured and predicted recovery was achieved. This proposed method would enable one to better understand the effect of moisture content and tenor of run of mine ore on recovery Daha fazlası Daha az

Yilmaz S. | Bilen M.

Book Part | 2016 | XVIII International Coal Preparation Congress: 28 June-01 July 2016 Saint-Petersburg, Russia , pp.953 - 957

In this study empirical relationship of HGI (Hard Groove Grindability Index) was established in terms of proximate analysis of coal. HGI is important parameter at mining applications such as excavation, crushing, grinding, dust generation. HGI has long been researched and empirical equations evaluating coal proximate analysis data has been proposed. Grindability of coal should be in consideration for power plant operators as well since milling requires high energy and no frequent maintenance is desired for mills. Determination of HGI experimentally takes time and studies address on the estimation of them in an easier way. Proximate . . .analysis of coal is easily evaluated and coals are classified with respect to their proximate analysis results. That is why, with the help of proximate analysis data, method can be developed to estimate HGI..In this study user friendly methods were proposed to predict HGI and this could be helpful tool for the initial estimates. This user friendly method was proposed and applied on the data taken from previous studies. Proposed estimation method of HGI are in good agreement with the previous studies’ results. © Springer International Publishing Switzerland 2016 Daha fazlası Daha az

Çuhadaroglu D. | Sirkeci A.A. | Bilen M. | Kizgut S. | Yilmaz S. | Yilmaz C.E.

Conference Object | 2017 | IMCET 2017: New Trends in Mining - Proceedings of 25th International Mining Congress of Turkey , pp.433 - 437

Coal can be regarded as an aggregation of organic and inorganic materials. Most of the minerals associated with the inorganic material are mainly clay minerals, quartz, carbonates, sulfides, and sulfates. In this study, brown coal samples were collected from 10 different brown coal pits in Turkey. Firslty, these coal samples were cleaned in terms of density seperation. Secondly, ash contents of original and clean coal samples were determined. Thirdly and finally, HGI (Hard Groove Index) values were determined for each sample of clean and run of mine coals. According to obtained HGI results for the run of mine coal samples; Gürmin-Me . . .rzifon brown coal has the highest HGI value as 68.5, while Saray-Tekirdag brown coal has the lowest HGI value as 43.5, respectively. HGI results for the clean coal samples; Ilgin-Konya brown coal has the highest HGI value as 84.4, while Orhaneli-Bursa brown coal has the lowest HGI value as 40.8, respectively. Evaluating the all results of HGI and ash content analysis, as ash making minerals reduce down with density seperation, HGI values are tend to increase. Coals containing higher mineral contents are more difficult to fracture compared to the ones having less mineral content Daha fazlası Daha az

Bilen M. | Kizgut S. | Cuhadaroglu A. | Yilmaz S. | Toroglu İ.

Article | 2017 | International Journal of Coal Preparation and Utilization37 ( 5 ) , pp.279 - 284

An empirical relationship of the Hardgrove Grindability Index (HGI) was established in terms of breakage parameters. In order to model particle-breakage behavior in a crusher, breakage parameters and HGI of material should be taken into consideration. Coal grindability has long been studied and empirical equations evaluating coal characteristics data have been proposed. Basically knowing the size distribution of the feed coal to the crusher and obtaining an experimental product size distribution after processing could help to model the operation conditions of the device. Breakage processes for coal have been modelled namely as ?-bre . . .akage process, ?, ?-breakage process and ?, ?, ?-breakage process (?: proportion selected for breakage in an assembly, ?: number of breakage in a breakage operation ?: coefficient of size dependence). Having evaluated the breakage model for any crusher, the size distribution of crushed coal and its HGI could be related to each other. An empirical method between HGI and ? proposed in this study was in good agreement with the experimental results. Experimental analysis of the crusher feed coal yielded an average HGI of 66 and the predicted HGI values were in the range of ± 10% of this average by employing the proposed method. As a second contribution of the proposed method, the stabilization of the size distribution of the crushed coal can be achieved with a decision mechanism for the plant operators about communition process. © 2017 Taylor & Francis Daha fazlası Daha az