Maden Mühendisliği Bölümü/Makale Koleksiyonu
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Öğe The effect of single and combined coagulation/flocculation methods on the sedimentation behavior and conductivity of bentonite suspensions with different swelling potentials(TAYLOR & FRANCIS INC, 2019) Onen, V.; Gocer, M.In this study, the sedimentation behavior of bentonite (Na and Ca bentonite) suspensions with different swelling potentials was investigated with single and combined coagulation and flocculation methods. The samples exhibited a negative surface charge over a broad pH range and had a relatively high suspension stability. Al-2(SO4)(3), FeCl3, MgCl2, CaCl2, and NaCl were used as coagulants. All coagulants have provided sedimentation efficiencies higher than 85% with Ca bentonite suspension, but only 22% efficiency was seen with Na bentonite suspensions. The effectiveness of coagulants increased with higher ionic values of the metal salts. Versus monovalent cations, multivalent cations had a greater influence on the zeta potential of the samples. Higher coagulant concentrations enhance the conductivities of the suspensions. In flocculation, anionic (A-150), cationic (C-521) and nonionic (N-100) flocculants were used. For a Ca bentonite suspension, all flocculants have 98% efficiency. The anionic flocculant was more efficient than cationic and nonionic ones for Na bentonite suspension. The dual-flocculation of cationic and anionic flocculant combinations and pre-destabilization via coagulants of Na bentonite suspension were also studied. Better flocculation performance was achieved with these combined methods.Öğe Effect of coagulants and flocculants on dewatering of kaolin suspensions(2018) Önen, Vildan; Göçer, Muhammed; Taner, Hasan AliKaolin tailings are commonly generated in the mineral industry. They are invariably negatively charged andconsequently tend to form stable dispersions with poor flocculation characteristics. Coagulation–flocculationtreatments are suitable methods for removing colloidal particles from wastewater. In this study, the effects ofmono/multivalent ions (coagulants) and polymers (flocculants) on the sedimentation and electrokineticbehaviours of kaolin have been investigated. In experimental studies, Al2(SO4)3, FeCl3, MgCl2, CaCl2, NaClwere used as coagulant, while as flocculant anionic (A150), cationic (C521) and nonionic (N100) polymers wereused. Isoelectric point of kaolin was determined as pH 4.2. The effectiveness of coagulants increased with theincrease in the ionicity degree of the metal ions. Among the coagulants, FeCl3 provided the highest efficiency(91%). Low sedimentation velocities (6.3-12.2 mm/min) were obtained with coagulants. The highestsedimentation efficiency (94%) was achieved with anionic flocculants and the same sedimentation velocity (58mm/min) was reached with all flocculants.Öğe Some geological features of limestone aggregates produced from central anatolian carbonate formations(2018) Kansun, Gürsel; Zedef, Veysel; Koçak, KerimF or the last fifteen years, there has been extensive motorway and railway constructions in Turkey. This requires enormous amount of road-fillers and aggregates, and the construction companies open many open-pit limestone quarries to fulfill their aggregate needs. The partly double (four lines), partly one-way (double line) motorway of KonyaHüyük have recently been enlarged and partly re-constructed. During this construction, a total of five limestone quarry were opened to produce limestone aggregate. The Bozlutepe Limestone member of Asmalıtepe Formation near the town of Selki (HüyükKonya, central Anatolia) were used for this demand, and it has been operated for the last 6 years. The limestone member is approximately 200 m thick at most and mostly made of three type of minerals and these are dolomitic limestone, crystalline limestone and quartz-bearing crystallized limestones. All the minerals are crystallized and the minerals locally dominate at the quarry. The produced aggregates have relatively flat granulometry curve indicating most of the grains are of thin and have clay-silt sized particles. Our studies revealed that Bozlutepe Limestones are formed in carbonate facies in shallow marine environments during Permian-Carboniferous times. The member most likely have low-grade metamorphism during Paleozoic and Mesozoic erasÖğe Ülkemizdeki Maden Sektöründe Meydana Gelen İş Kazası ve Meslek Hastalıklarının Analizi(2018) Bilim, Niyazi; Dündar, Sertaç; Bilim, AtiyeMadencilik sektörü dünyada kişi başına iş kazası oranlarının en büyük olduğu sektörlerden birisidir. Ülkemizdekidurumda da dünyadaki ile örtüşmektedir. Çünkü madencilik sektörü doğası gereği en riskli iş kollarından birtanesidir. Bu nedenle, bu sektörde çalışanlar daha dikkatli olmak zorundadır. Ülkemizde meydana gelen işkazalarının madenlerde azaltılmasına yönelik son yıllarda devletin ve işverenlerin gerçekleştirdiği önemli ve umutverici olumlu gelişmeler kaydedilmiştir. Özellikle maden işyerleri için ek önlem paketleri getirilmiş ve güvenlikkültürünün oturtulması yönünde çalışmalar hızlandırılmıştır. Bu çalışmada, madencilik sektöründe 2012-2016yıllarında (son beş yıl) meydana gelen iş kazaları ve meslek hastalıkları ana ve alt sektörler ile birlikte ayrıntılıanaliz edilmiştir. İş kazası analizlerinde önemli bir gösterge olan kaza olabilirlik oranı, maden sektöründeki anave alt sektörlerle birlikte belirlenerek değerlendirilmiştir. Maden sektörünün iş güvenliği açısından durumu diğerbazı sektörler ile karşılaştırılarak yorumlar yapılmıştır. Sonuçta; iş kazalarında az da olsa bir azalma eğiliminegirildiği görülmekte olup, bunun daha yüksek bir düşüş eğilimine girebilmesi için yapılması gerekenler noktasındabazı önerilerde bulunulmuştur.Öğe Ilgın kömürlerinin termogravimetrik analiz yöntemi ile gazlaşma özelliklerinin incelenmesi(2018) Çınar, İbrahim; Altun, MustafaKömür oluşumu itibariyle heterojen bir yapıya sahiptir. Bundan dolayı kömürün gazlaşmasını etkileyen birçok etken vardır. Isıl analiz kömürün gazlaşma özelliklerinin belirlenmesinde ve bu etkenlerin kömürün gazlaşma özellikleri üzerindeki etkilerinin incelenmesinde en iyi yöntemlerden birisidir. Bu çalışmada Ilgın kömürlerinden alınan numunelerle belirlenen sıcaklıklarda dönüşüm süreleri ve gazlaşma hızları termogravimetrik analiz yöntemiyle belirlenmiş sıcaklığın bu faktörler üzerindeki etkileri incelenmiştir. Ilgın kömürleri 700C, 750C, 800C ve 850C sıcaklıklarda CO2 atmosferinde termogravimetrik analiz cihazı kullanılarak gazlaştırılmış dönüşüm oranları ve gazlaşma hızları incelenmiş ve numuneler arasında karşılaştırmalar yapılmıştır. Ilgın kömürünün 800C sıcaklıkta diğer sıcaklıklara göre daha kısa sürede dönüşümünün tamamlandığı görülmüştür.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 Yeraltı maden ocaklarında aydınlatma koşullarının belirlenmesi(2017) Çınar, İbrahim; Şensöğüt, CemBu çalışmada, iş sağlığı ve güvenliği açısından çok önemli olan işyerlerinin aydınlatılması ile ilgili temel bilgiler verilerek iyi bir aydınlatmanın nasıl yapılması gerektiği açıklanmıştır. Yeraltı maden işletmelerinde yeterli aydınlatma koşullarının oluşturulmasının iş sağlığı ve güvenliği açısından önemi ifade edilmiştir. Ayrıca iki farklı yeraltı maden işletmesinde yapılan aydınlatma ölçümleri verilerek yasal sınırlamalar vurgulanmış, yetersiz aydınlatma durumunda yapılması gerekenler ve yaşanabilecek olumsuz durumlar hakkında bilgi verilmiştirÖğe Taguchi deneysel tasarım metodu kullanılarak karadon (zonguldak) kömürünün yağ aglomerasyonu davranışının incelenmesi(2016) Düzyol, SelmaÜlkeler, sahip oldukları yerli kaynakları kullanarak hem dışa bağımlılıklarını azaltabilir hem de bu bağımlılığa dayalı ekonomik kayıpların önüne geçebilirler. Bu düşünce ışığı altında, ülkemiz kömürlerinin ve özellikle ince boyutta olanlarının en az kayıpla değerlendirilmesi, yeterli bir planlamayı takiben etkin bir uygulama ile mümkündür. Bu çalışmada ince boyuttaki Karadon (Zonguldak) kömürlerinin yağ aglomerasyonu yöntemi ile zenginleştirilmesi, çeşitli parametreler ışığı altında araştırılmıştır. Deneysel çalışmalar, Taguchi (L16) deneysel tasarım yöntemi kullanılarak planlanmış ve yağ aglomerasyonunun başarısı, elde edilen aglomeratların kül içeriği ve yanabilir kısım verimi (YKV) ile değerlendirilmiştir. Deneysel tasarım ile farklı şartlar altında 16 adet aglomerasyon deneyi gerçekleştirilmiş, anlam analizi ile optimizasyon çalışmaları neticesinde doğrulama deneyi yapılmıştır. Yapılan analizler neticesinde, 39,48 olan en yüksek sinyal/gürültü (S/G) oranına Test 2 ile ulaşılmış ve bu deneyden elde edilen aglomeratların ortalama YKV değerinin %94,2 ile en yüksek olduğu belirlenmiştir. En büyük aglomerat boyutları (ortalama 5-7 mm) Test 16'dan elde edilmiş ancak YKV değerlerinin düşük olduğu görülmüştür.Öğe Evaluation of critical parameters for wettability-based processes in mineral processing(2015) Özkan, Alper; Düzyol, SelmaThis paper presents an evaluation of critical parameters for wettability-based processes such as flotation, shear flocculation, oil agglomeration and liquid–liquid extraction in mineral processing. ‘The critical surface tension of wetting (?c)’ value of minerals has crucial importance in these processes. Also, ‘the critical solution surface tension for oil agglomeration (?c-a)’ and ‘the critical solution surface tension for liquid?liquid extraction (?c-e)’ parameters, which are slightly higher than the ?c value of the mineral, exist for achieving the oil agglomeration and liquid?liquid extraction techniques. In the case of three-phase systems composed of solid, liquid/medium and oil such as oil agglomeration and liquid?liquid extraction techniques, there is a second critical parameter based on the oil?liquid interfacial tension (?OL) which are ‘the critical oil?liquid interfacial tension for oil agglomeration, ?c?OL?a’ and ‘the critical oil?liquid interfacial tension for liquid?liquid extraction, ?c?OL?e’, respectively.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 Optimum Cutting Speed of Block-Cutting Machines in Natural Stones for Energy Saving(JOURNAL OF CENTRAL SOUTH UNIV, 2012) Bilim, N.Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of major importance in the natural stone-processing industry. An experimental study was carried out utilizing a fully instrumented block-cutter to investigate the sawing performances of five different types of travertine blocks during cutting with a circular diamond saw. The sawing tests were performed in the down-cutting mode. Performance measurements were determined by measuring the cutting speed and energy consumption. Then, specific energy was determined. The one main cutting parameter, cutting speed, was varied in the investigation of optimum cutting performance. Furthermore, some physico-mechanical properties of the travertine blocks were determined in the laboratory. As a result, it is found that the energy consumption (specific energy) of block cutting machines is highly affected by cutting speed. It is determined that specific energy value usually decreases when cutting speed increases. When the cutting speed is higher than the determined value, the diamond saw can become stuck in the travertine block; this situation can be a problem for the block-cutting machine. As a result, the optimum cutting speed obtained for the travertine mines examined is approximately 1.5-2.0 m/min.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 Role of Hydrophobicity and Surface Tension on Shear Flocculation and Oil Agglomeration of Magnesite(Elsevier Science Bv, 2010) Düzyol, Selma; Özkan, AlperThis paper describes the role of hydrophobicity and surface tension on the shear flocculation and oil agglomeration of magnesite mineral. The experimental results have demonstrated that these processes were closely correlated with the particle hydrophobicity; however, they were not lowered by increasing the surface charge due to sodium oleate adsorption. Also, higher degrees of hydrophobicity were required to achieve the maximum aggregation in the oil agglomeration of magnesite fines in comparison to its shear flocculation. On the other hand, these aggregation processes decreased depending on the decrease in the contact angle with decreasing surface tension. Eventually the shear flocculation and oil agglomeration of fine particles in the suspension did not take place below a particular value of surface tension, corresponding the critical surface tension of wetting (gamma(c)) and the critical solution surface tension (gamma(c-a)) values, respectively.Öğe Performance of Natural Zeolite and Sepiolite in the Removal of Free Cyanide and Copper-Complexed Cyanide ([Cu(CN)(3)](2-))(Clay Minerals Soc, 2010) Tarlan Yel, Esra; Önen, VildanThe chemical and biological methods employed to date in the removal of free cyanide (CN-) and metal-cyanide complexes from aqueous fluids have proved expensive and problematic. A simpler and more economical approach was attempted in the present study using zeolite and sepiolite. The effectiveness of zeolite from Manisa-Gordes (Turkey) and of sepiolite Eskisehir-Sivrihisar (Turkey) at removing free and Cu-complexed cyanide, [Cu(CN)(3)](2-) was investigated. For removal of CN-, the system performance was examined in terms of concentration, particle size, and retention time. Material with smaller particle sizes (<0.106 mm) performed better, particularly in the case of sepiolite. The maximum CN- removal capacities of zeolite and sepiolite were calculated as 571 and 695 meq/100 g for free CN adsorption, and 455 and 435 meq/100 g for Cu-complexed CN adsorption, respectively. The time to reach equilibrium was calculated as 1050 min. Acid activation, a simple cation adsorption removal method, did not improve the process, instead leading to reduced CN adsorption. Hydroxylated surfaces of metal oxides at the edges of zeolite develop charges and exchange with anions in water. Mg2+ ions located at the edges of the octahedral sheet can create complexes with CN- anions. Moreover, hydrogen bonding with anions (CN- in this case) and H+ of zeolitic water bonded to coordinated water molecules can also create complexes. These two complexes are considered to be effective mechanisms for sepiolite. The effects of both acid activation and CN adsorption were clearly observed in the Fourier-transform infrared spectra. Removal of CN was characterized by the Langmuir isotherm, indicating monolayer coverage with chemical bonding to the surface, which deteriorated during acid activation. The study indicated that zeolite and sepiolite can be used efficiently and easily for removal of free and Cu-complexed CN.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 Internet-Based Monitoring and Prediction System of Coal Stockpile Behaviors Under Atmospheric Conditions(Springer, 2010) Yılmaz, Nihat; Özdeniz, A. HadiSpontaneous combustion on industrial-scale stockpiles causes environmental problems and economic losses for the companies consuming large amounts of coal. In this study, an effective monitoring and prediction system based on internet was developed and implemented to prevent losses and environmental problems. The system was performed in a coal stockpile with 5 m width, 10 m length, 3 m height, and having 120 t of weight. The inner temperature data of the stockpile was recorded by 17 temperature sensors placed inside the stockpile at certain points. Additionally, the data relating to the air temperature, air humidity, atmospheric pressure, wind velocity, and wind direction that are the parameters affecting the coal stockpile were also recorded. The recorded values were analyzed with artificial neural network and Statistical modeling methods for prediction of spontaneous combustion. Real-time measurement values and model outputs were published with a web page on internet. The internet-based system can also provide real-time monitoring (combustion alarms, system status) and tele-controlling (Parameter adjusting, system control) through internet exclusively with a standard web browser without the need of any additional software.Öğe Determination of Spontaneous Combustion in Industrial-Scale Coal Stockpiles(TAYLOR & FRANCIS INC, 2010) Özdeniz, A. H.Many companies unavoidably store coals at their stock areas for later usage. Stock fires take place due to long-term stay of these coals at the stock areas and cause serious damages in terms of economy and environment. In order to determine the occurrence conditions of spontaneous combustion of coals due to long-term stay under natural air conditions, an industrial-scale coal stockpile composed of 10 to 18 mm coal grains, having the dimensions of 5 m width, 3 m height, and 10 m length and weighing approximately 120 tons, was formed in a coal stock area of a company using great amounts of coal annually. Recording the temperature values measured at the stockpile, the temperature-time diagrams were plotted. Moreover, the atmospheric effects on the stockpile were investigated by continuously measuring air temperature, air humidity, atmospheric pressure, velocity, and direction of wind, which are some of the parameters affecting the stockpile.Öğe Critical Solution Surface Tension for Liquid-Liquid Extraction(ELSEVIER, 2010) Özkan, A.; Düzyol, S.This paper introduces a strong correlation between the solution surface tension and the liquid-liquid extraction process of minerals. It was found that the liquid-liquid extraction recoveries of celestite, magnesite and dolomite minerals decreased with decreasing solution surface tension, and eventually the liquid-liquid extraction of these minerals did not take place below a particular value of the solution surface tension. The solution surface tension value at which liquid-liquid extraction does not occur was defined as 'the critical solution surface tension for liquid-liquid extraction, gamma(c-e)'. Consequently, the solution surface tension value for a successful liquid-liquid extraction of a mineral must be higher than the critical solution surface tension of liquid-liquid extraction (gamma(c-e)) value. In addition, the experimental results have demonstrated that the gamma(c-e) values obtained from liquid-liquid extraction tests of these minerals were slightly higher than their critical surface tension of wetting (gamma(c)) values based on the contact angle measurement technique. These differences between the gamma(c-e) and the gamma(c) values indicate that the liquid-liquid extraction process of the minerals took place after reaching a sufficiently low wettability.Öğe Effects of Electrical Resistance on the Spontaneous Combustion Tendency of Coal and the Interaction Matrix Concept(Int Journal Minerals Metallurgy & Materials, Editorial Dept, 2006) Yıldırım, O. S.; Şensöğüt, Cem; Gökay, Mehmet KemalThere have been several developments in determining the spontaneous combustion liability of coal. Most of the methods of concern have purely been based on the internal properties of the coal itself. The relation between the crossing-point method and the electrical resistance of coal was examined here to outline the spontaneous combustion tendency of coal. The electrical resistance property of coal was looked into as a decision-making parameter of the interaction matrix concept for the final decision on the spontaneous combustion tendency.Öğe Effect of the Textural Properties of Rocks on Their Crushing and Grinding Features(Journal of Univ of Science and Technology Beijing, 2006) Kekeç, Bilgehan; Ünal, M.; Şensöğüt, CemTo study the effect of the textural properties of rocks on their crushing feature, the distribution of particle size, the texture, grinding and crushing characteristics of the rocks were investigated, and the relations among them were then analyzed using statistical methods. The relations between the textural properties and the physical and mechanical features of rocks were determined.
