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Öğe Benefication of low-grade chromite ores of abandoned mine at Topraktepe, Beysehir, SW Turkey(BERG FAC TECHNICAL UNIV KOSICE, 2007) Ağaçayak, Tevfik; Zedef, Veysel; Aydoğan, SalihOptimum enriching possibilities of chromite ores from the abandoned Topraktepe mine were investigated. To obtain the best enriching method(s), shaking table, multi gravity separator, humprey spiral and jigging tests were tested. The best grades for Cr2O3 are 55.65% by shaking table, 57.52% by multigravity separator, 54.58% by humprey spiral test and 50.68% by jigging. To provide these results, the particle sizes of the ore are -0.3 to 0.212 mm for shaking table, -0.106 to 0.075 mm for multi gravity separator, -0.3 to 0.212 mm for humprey spiral and -2 to 1 mm for jigging. Regarding the best grades obtained, the recoveries for shaking table, multi gravity separator, humprey spiral and jigging methods are 85.38%, 79.83%, 94.89% and 87.58% respectively. The results of these tests show that a further recovery of remaining 500 000 tons of ore could be possible from the abandoned Topraktepe chromite deposit.Öğe Breakage Parameters of Some Minerals and Coals Ground in a Laboratory Size Ceramic Mill(Natl Inst Science Communication, 2003) Özkan, Alper; Yekeler, Meftuni; Aydoğan, SalihThe kinetics of batch dry and wet grindings of calcite, barite, quartz, lignite and anthracite from feeds of sieve size - 425+300 µm has been determined using a laboratory scale ceramic ball mill. The S₁ values obtained were the highest (0.294 min') for anthracite and the lowest (0.071 min¹) for quartz when ground dry. However, the wet grinding of these materials gave higher S, values by a factor of 1.28 for calcite, 1.15 for barite, 1.25 for quartz, 1.11 for lignite and 1.07 for anthracite comparing to the dry S₁ values. The B₁ values also changed for all the materials ground as dry and wet. The simulations of the product size distributions for both first-order and non-first order breakage of the materials ground were in good agreement with the experimental size distributions. There is a relationship between the S, values and the y value of Bij parameter; i.e., S, values increase when y values decrease, indicating that faster breakage rates of top sizes produce more fines in the finer size distribution region (-150 µm),Öğe Dissolution Kinetics of Celestite (SrSO4) in HCl Solution with BaCl2(Elsevier Science Bv, 2006) Aydoğan, Salih; Erdemoğlu, Murat; Aras, Ali; Uçar, Gökhan; Özkan, AlperLeaching of celestite (SrSO4) in hydrochloric acid solution with BaCl2 was investigated to produce SrCl2 in solution, which is the main source for SrCO3. The effects of variables such as stirring speed, BaCl2 and HCl concentrations, and temperature and particle size, and also the presence of NaCl in the leaching solution were studied. The leaching was modeled according to the shrinking core model. The activation energy for the leaching process in 8.25 x 10(-3) M BaCl2 solution equilibrated with 0.5 M HCl was found as 68.8 U mol(-1). This value reveals that the dissolution of celestite is a chemical reaction controlled process. In agreement with the model, the reaction rate is inversely proportional to the particle size and increases as 0.73, 0.70 and 0. 19 powers of the H+, Cl- and Ba2+ concentrations, respectively.Öğe DISSOLUTION OF LATERITIC NICKEL ORE IN SULPHURIC ACID MEDIUM WITH POTASSIUM DICHROMATE(INT SCIENTIFIC CONFERENCE SGEM, 2008) Ağaçayak, Tevfik; Aydoğan, Salih; Zedef, VeyselIn this study, leaching of Ni and Fe in suphuric acid medium with K2Cr2O7 was investigated. The samples of the lateritic nickel ore were taken from Karacam (Eskisehir) region of Turkey. Mineralogical investigations showed that the ore sample contains, goethite, hematite, wustite, retgersite, gaspeite and clay type minerals together with quartz. The shrinking core model was applied to the results of experiments investigating the effects of leaching temperature range of 50-96 degrees C. Two equations were applied from obtained results from each temperature value. Their correlation coefficients for each temperature are calculated. These results indicate that the dissolution rate of Ni is controlled by diffusion. The activation energy for the leaching process was found to be 68.43 kJ/mol and the Arrhenius constant was calculated to be 8.231 s(-1).Öğe LEACHING OF CHALCOPYRITE CONCENTRATE IN HYDROGEN PEROXIDE SOLUTION(OFICYNA WYDAWNICZA POLITECHNIKI WROCLAWSKIEJ, 2014) Ağaçayak, Tevfik; Aras, Ali; Aydoğan, Salih; Erdemoğlu, MuratThe leaching conditions of chalcopyrite (CuFeS2) concentrate in a hydrogen peroxide medium were investigated by studying the effects of its leaching parameters, such as stirring speed, temperature, hydrogen peroxide concentration and the particle size of the concentrate on Cu extraction. It was found that stirring speed has no effect on the leaching. Copper extraction from chalcopyrite is directly proportional to hydrogen peroxide concentration, but the extraction decreases at temperatures above 60 degrees C. The maximum copper extraction was obtained with the following conditions without stirring: 240 min of leaching time, 3.0 M hydrogen peroxide concentration, 40 degrees C leaching temperature and 53-75. m particle size fraction.Öğe LEACHING OF LATERITIC NICKEL ORES OF KARACAM (ESKISEHIR-TURKEY) WITH HYDROCHLORIC ACID(INT SCIENTIFIC CONFERENCE SGEM, 2011) Ağaçayak, Tevfik; Zedef, Veysel; Aydoğan, SalihIn this study, nickel extraction from Karacam (Eskisehir) region laterites by hydrochloric acid leaching is aimed. The mineralogical analysis showed that the ore sample contains goethite, hematite, wustite, retgersite, gaspeite and clay type minerals together with quartz. The effects of various parameters such as leaching time, stirring speed, acid concentration and leaching temperature on nickel recovery were determined. The shrinking core model was applied to the results of experiments investigating the effects of leaching temperature range of 40-90 degrees C. Two equations were applied from obtained results from each temperature value. Their correlation coefficients for each temperature are calculated. These results indicate that the dissolution rate of Ni is controlled by diffusion. The activation energy (Ea) for the dissolution reaction was calculated as 74.52 kJ/mol. Arrhenius constant was calculated to be 8.9633 s(-1).Öğe Neural Model for the Leaching of Celestite in Sodium Carbonate Solution(ELSEVIER SCIENCE SA, 2010) Bingöl, Deniz; Aydoğan, Salih; Gültekin, S. SinanA neural model for computing the conversion kinetics of SrSO(4) to SrCO(3) was investigated in sodium carbonate solution, based on the multilayered perceptrons was presented. For this purpose the artificial neural network (ANN) method was used. The effects of stirring speed, temperature, mole ratio Na(2)CO(3):SrSO(4) and particle size of the celestite on leaching kinetics were studied. The surface transformation of celestite to strontium carbonate in aqueous carbonate solutions was also supported by FT-IR spectroscopy. The conversion rate of celestite increases systematically with increasing temperature (up to 70 degrees C). Furthermore, the feasibility of replacing the SO(4)(2-) ions with CO(3)(2-) ions in the structure of the leached solid was also investigated by FT-IR. FT-IR results showed that the replacement of SO(4)(2-) ions in celestite by CO(3)(2-) ions in leaching conditions was nearly completed at 60 degrees C with a mole ratio Na(2)CO(3):SrSO(4) = 4:1, solid to liquid =5:500, -212+106 mu m particle size, and 400 rpm stirring rate for an interval of 240 min. The first (up to 90 min) conversion result obtained was trained with an extended delta-bar-delta algorithm (EDBD), which is in the multilayered perceptions and is a neural model structure. Results of other conversion times (90-240 min) results were predicted. Results predicted by the neural model were in very good agreement with the experimental results.Öğe Optimization of the Wet Mechanochemical Process Conditions of SrSO4 to SrCO3 and (NH4)(2)SO4 by Using Response Surface Methodology(SPRINGER, 2012) Bingöl, Deniz; Aydoğan, Salih; Karayünlü Bozbaş, SedaThe wet mechanochemical process was optimized for insoluble SrCO3 and soluble (NH4)(2)SO4 formation from celestite (SrSO4)-(NH4)(2)CO3-H2O mixtures in a planetary ball mill by Box-Behnken design (BBD). The products formed during wet milling were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. For converting to SrCO3 of celestite (SrSO4) and to (NH4)(2)SO4 of (NH4)(2)CO3, a hydrometallurgical process optimization via the wet mechanochemical conversion using (NH4)(2)CO3 was developed the first time in this work using response surface methodology. The wet mechanochemical conversion was carried out by varying ball to grinding material mass ratio, (NH4)(2)CO3 to SrSO4 mole ratio and the rotational speed of mill in a planetary mill. Under the optimum experimental conditions (9.24 of ball to grinding material mass ratio, 1.86 of (NH4)(2)CO3 to SrSO4 mole ratio and 400 rpm of the rotational speed of mill), the conversion of SrCO3 was 99.08 pct. The (NH4)(2)SO4 obtained as byproduct was crystallized.Öğe Oxidative ammonia leaching of sphalerite concentrate(Selçuk Üniversitesi Mühendislik-Mimarlık Fakültesi, 2005) Aydoğan, Salih; Aras, Ali; Canbazoğlu, MehmetThis paper presents a study of kinetics of leaching of sphalerite concentrate in ammonia solutions. The effects of ammonia concentration, oxygen partial pressure, reaction temperature and particle size on the leaching rate were investigated. The shrinking core model was applied to the results obtained from these experiments. Reaction order with respect to PO2 (1-10 atm.) and NH3 concentration (1.05-5.20 M) were 0.22 and 0.63 and the activation energy was determined to be 43.59 kj/mol in the temperature range of 90-130 °C. In addition, the apparent rate constant is in inverse relationship with the mean initial particle radius. The results of this study showed that the leaching of sphalerite was a reaction controlled process.Öğe Production of SrCO3 and (NH4)(2)SO4 by the Dry Mechanochemical Processing of Celestite(ELSEVIER SCIENCE INC, 2012) Bingöl, Deniz; Aydoğan, Salih; Karayünlü Bozbaş, SedaA SrCO3 formation starting from activated SrSO4-(NH4)(2)CO3 mixtures as a result of dry mechanochemical treatment for 180 min in a planetary ball mill of celestite together with (NH4)(2)CO3 was studied. The phases that formed during milling were successfully characterized by X-ray diffraction measurement (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and chemical analysis. A novel hydrometallurgical process to convert both SrCO3 (product) and (NH4)(2)SO4 (by-product) from celestite via dry mechanochemical conversion with (NH4)(2)CO3 was developed for the first time in this work. Under optimum conditions, the conversion of SrCO3 was 98.1%. The (NH4)(2)SO4 leach solution was crystallized.Öğe Recovering of Ni, Co and Cu from Divrigi Iron Plant tailings by sulphuric acid oxygen pressure leaching(2006) Canbazoğlu, Mehmet; Kaya, Oktay; Akdemir, Ünal; İnan, Aslı; Aydoğan, SalihTurkish Iron and Steel Company at its Divrigi concentrator plant produces magnetite concentrate for sintering using dry and wet magnetic separation. Nearly 750.000 tons of tailings are sent to tailings dam from Divrigi concentrator every year. These tailings contain 0.11 % Cu, 0.145 % Co, 0.35 % Ni, 0.25 g/t Au and 2.2 g/t Ag. The mineralogical composition of these tailings is complex and the minerals of the important metals are present as oxide and sulphides showing fine-grained structure. In this study, the recovery of these metals as Cu, Co and Ni was investigated, using oxidative sulphuric acid pressure leaching. The investigated parameters were leaching time (1 to 8 h), leaching pH (0.5 to 2), leaching temperature (110 °C to 180 °C) and partial oxygen pressure (1 to 6 bar). Under the optimum experimental conditions that were 4 h of leaching, 0.5 pH, temperature of 110 °C and oxygen pressure of 4 bar, the obtained recoveries were 64.10% Ni, 65.01% Co and 76.40% Cu.Öğe Topraktepe-Beyşehir (Konya) kromitlerinin yüksek alan şiddetli yaş manyetik ayırma ile zenginleştirilmesi(Selçuk Üniversitesi Mühendislik-Mimarlık Fakültesi, 2004) Ağaçayak, Tevfik; Zedef, Veysel; Aydoğan, SalihBu çalışmada, ADO Madencilik A.Ş. tarafından işletilmiş ve daha sonra terkedilmiş olan Topraktepe-Beyşehir (Konya) kromitlerinin “Boxmag Rapid LHWL” tipi yüksek alan şiddetli yaş manyetik ayırıcı ile optimum koşullarda zenginleştirilebilme olanakları araştırılmıştır. Manyetik ayırma deneyleri, -0.106+0.075 mm, -0.075+0.053 mm, -0.053+0.038, -0.038+0.000 mm boyutlarında 250 gramlık numuneler ile yapılmıştır. Her bir boyut için ayrı ayrı akım şiddetinin ve voltaj değerlerinin Cr2O3 tenörüne ve verimine etkisi incelenmiştir. Deneylerde dört ayrı fraksiyon aralığında 5, 10, 20 amperlik akım şiddeti ve 40, 90, 185 volt değerleri test edilmiştir. Yapılan deney sonuçlarına göre, 20 amper akım şiddetinde en iyi sonuçların alındığını görülmüştür. Bu sonuçlara göre, -0.106+0.075 mm fraksiyonunda 20 amper akım şiddetiyle % 69.37 ağırlık oranında, % 86.67 verim ile % 51.06 Cr2O3 tenörlü konsantre, - 0.075+0.053 mm fraksiyonunda 20 amper akım şiddetiyle % 77.32 ağırlık oranında, % 86.55 verim ile % 51.74 Cr2O3 tenörlü konsantre, -0.053+0.038 mm fraksiyonunda 20 amper akım şiddetiyle % 47.18 ağırlık oranında, % 60.14 verim ile % 50.13 Cr2O3 tenörlü konsantre, -0.038 +0.000 mm fraksiyonunda 20 amper akım şiddetiyle % 39.75 ağırlık oranında, % 69.74 verim ile % 49.79 Cr2O3 tenörlü konsantre, elde edilmiştir.Öğe Wet mechanochemical processing of celestine using (NH4)2CO3(2017) Bingöl, Deniz; Aydoğan, Salih; Bozbaş, Seda KarayünlüIn this study, traditional (univariate) method of processing to the wet mechanochemical treatment were applied toobtain both SrCO3 and (NH4)2SO4 from celestite (SrSO4)-(NH4)2CO3-H2O mixtures in a planetary ball mill. X-raydiffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were usedto analyze products formed during wet milling. A hydrometallurgical process was carried out to examine milling time,ball to grinding material mass ratio, (NH4)2CO3 to SrSO4 mole ratio and rotational speed of the mill in a planetary mill.Under optimum conditions, a conversion approaching 100% of SrCO3 was obtained.Öğe Yeşildağ (Beyşehir-Konya) kromit cevherinin flotasyon ile zenginleştieşrilme olanaklarının araştırılması(Selçuk Üniversitesi Mühendislik-Mimarlık Fakültesi, 2006) Ağaçayak, Tevfik; Zedef, Veysel; Aydoğan, SalihBu çalışmada, Topraktepe (Yeşildağ-Beyşehir) kromit cevherinin “Denver” tipi flotasyon hücresi ile zenginleştirme olanakları araştırılmıştır. Flotasyonu deneyleri, -212 ?m boyutunda, % 23 katı oranında, 300 gramlık temsili numuneler kullanılarak yapılmıştır. Yapılan deneylerde pH değeri, Fe+3 iyonları ve köpük alma süresinin flotasyona etkisi araştırılmıştır. İlk olarak, kromit flotasyonu için optimum pH belirlenmiştir. Bu amaçla, deneyler 5,6,7 ve 8 pH değerlerinde yapılmıştır. Optimum pH değerinin belirlenmesinden sonra, kromit mineralini bastırmak için gerekli olan Fe+3 iyonlarının optimum miktarının belirlenmesine çalışılmıştır. Bu amaçla, 0.33,0.67,1.00,1.33,1.67 ve 3.33 g/ton konsantrasyonlarında Fe+3 iyonları kullanılarak flotasyon deneyleri aynı koşullarda tekrarlanmıştır. Diğer taraftan optimum flotasyon zamanının 10 dk olduğu bulunmuştur. Deneysel sonuçlardan elde edilen optimum sonuçlar aşağıdaki gibidir: pH 5, 10 dk flotasyon zamanı, 1.33 g/t Fe+3 konsantrasyonu, 50 g/t köpürtücü konsantrasyonu.
