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Öğe Correlation of Flocculation and Agglomeration of Dolomite with its Wettability(TAYLOR & FRANCIS INC, 2011) Duzyol, S.; Ozkan, A.Wettability is an important parameter which affects the shear flocculation and oil agglomeration behaviors of minerals. The critical surface tension of wetting (c) as a wettability parameter describes wetting characteristics of any mineral. In this study, the correlation of shear flocculation and oil agglomeration processes of dolomite with its wettability parameter is investigated. The experimental studies have indicated that these processes improved with decreasing wettability depending on the increase of oleate adsorption despite a simultaneous increase in the zeta potential of dolomite. On the other hand, the flocculation and agglomeration of dolomite decreased with decreasing surface tension and did not occur below a particular value of surface tension, corresponding to the critical surface tension of wetting (c) and the critical solution surface tension (c-a) values, respectively. Also, the c-a values are slightly higher than the c values, indicating that the agglomeration of the particles requires a lower wettability.Öğe Correlation of shear flocculation of some salt-type minerals with their wettability parameter(ELSEVIER SCIENCE SA, 2007) Ozkan, A.; Uslu, Z.; Duzyol, S.; Ucbeyiay, H.This paper considers the importance of surface hydrophobicity in the shear flocculation process and presents a correlation between the shear flocculation and the wettability parameter for barite, celestite and calcite as salt-type minerals. The critical surface tension of wetting (gamma(c)) as a wettability parameter describes wetting characteristics of any mineral. The variation of the shear flocculation behaviours of barite, celestite and calcite with sodium oleate concentration in various methanol solutions was investigated. The shear flocculation of these minerals in the methanol solutions increased rapidly towards the optimum surfactant concentration, and thereafter remained relatively constant or increased slightly. On the other hand, the shear flocculation of the minerals decreased with increasing methanol concentration, depends on decreasing surface tension. The gamma(c) values of these minerals as a function of surfactant concentration were determined using a shear flocculation approach. It was found that the gamma(c) values did not change much at surfactant concentrations above the optimum. This result provides a reason for the observed lack of significant increase in the shear flocculation of the mineral suspensions when surfactant concentrations higher than the optimum are used. Furthermore, a strong correlation between the effective shear flocculation and the critical surface tension of wetting (gamma(c)) value was established. As the effective shear flocculation of these salt-type minerals increased sharply below a particular gamma(c) value, it was not much improved after reaching the gamma(c) value obtained at the optimum concentration of sodium oleate. (c) 2006 Elsevier B.V. All rights reserved.Öğe Critical oil-liquid interfacial tension for some oil-assisted fine particle processing methods(ELSEVIER SCIENCE BV, 2012) Duzyol, S.; Ozkan, A.; Yekeler, M.This paper presents that oil-liquid interfacial tension (gamma(OL)) value significantly affects the oil agglomeration and liquid-liquid extraction processes as oil-assisted methods in fine particle processing. The decrease in the oil-liquid interfacial tension leads to the decreases in the recoveries of minerals in both oil agglomeration and liquid-liquid extraction techniques. Eventually, these oil-assisted methods do not take place below a particular value of oil-liquid interfacial tension. The oil-liquid interfacial tension value at which oil agglomeration does not occur was defined as 'critical oil-liquid interfacial tension for oil agglomeration, gamma(c-OL-e)' and at which liquid-liquid extraction does not take place was also defined as 'critical oil-liquid interfacial tension for liquid-liquid extraction, gamma(c-OL-e)' Consequently, the oil-liquid interfacial tension of the medium for successful processes of oil agglomeration and liquid-liquid extraction of a mineral must be higher than the related critical interfacial tension value. (C) 2012 Elsevier B.V. All rights reserved.Öğe Effect of contact angle, surface tension and zeta potential on oil agglomeration of celestite(PERGAMON-ELSEVIER SCIENCE LTD, 2014) Duzyol, S.; Ozkan, A.The influences of contact angle, surface tension and zeta potential on oil agglomeration recovery of celestite mineral have been investigated in the present work. Therefore, celestite mineral in methanol-water suspension was agglomerated by the use of oil (kerosene) in the presence of sodium oleate as a surfactant. The zeta potential values of celestite surfaces were measured depending on pH and sodium oleate concentration. The zeta potential values of celestite surfaces became negative even more owing to the sodium oleate adsorption. However, this phenomenon did not affect the oil agglomeration recovery at all. It was found that both increasing contact angle and surface tension raised the oil agglomeration recovery of celestite mineral. Eventually, the agglomeration degree of celestite mineral in the suspension was not lower than a particular surface tension value corresponding to the critical solution surface tension for oil agglomeration (gamma(c-a)). The gamma(c-a) values were slightly greater than the critical surface tension of wetting (gamma(c)) values. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Flocculation of coal suspension with mono/dual polymer systems and contribution of Ca(II)/Mg(II) ions(TAYLOR & FRANCIS INC, 2016) Ozkan, A.; Oner, B.; Onen, V.; Duzyol, S.In the experimental study carried out on mono-flocculation, anionic and especially non-ionic polymers strongly flocculated the coal suspension than cationic polymer. The dual-flocculation of the coal suspension with cationic and anionic polymer combination was also studied and the high performances of flocculation were also reached with dual-polymer approach. Furthermore, dual-polymer system required lower concentrations for the successful flocculation of coal particles. On the other hand, the pre-destabilization of the coal suspension with calcium and magnesium ions at particular pH and concentrations highly improved the flocculation of fine coal particles with these polymers.Öğe Gamma processes of shear flocculation, oil agglomeration and liquid-liquid extraction(ELSEVIER, 2014) Ozkan, A.; Duzyol, S.Gamma flotation process is characterized by emphasis on the control of solution surface tension and the separation of minerals in suspension with this technique is based on the differences in wettability of minerals. The wettability properties of mineral surfaces can be defined in terms of their values of critical surface tension of wetting (gamma(c)) as a quantifying parameter, which is an essential property to achieve selectivity in surface chemistry-based separation processes. That is, the gamma flotation technique utilizes the differences in the critical surface tension of wetting (gamma(c)) of minerals. Similar to the flotation method, shear flocculation, oil agglomeration and liquid-liquid extraction processes also utilize differences in wettability of minerals. Therefore, the separations of minerals by the control of surface tension in the shear flocculation, oil agglomeration and liquid-liquid extraction methods can be provided. In this study, the separations of some minerals with these processes have been investigated by using the control of the solution surface tension and the successful results could be reached. Consequently, these new separation processes have been defined as 'gamma shear flocculation', 'gamma oil agglomeration' and 'gamma liquid-liquid extraction'. (C) 2014 Elsevier B.V. All rights reserved.Öğe The relation between hydrophobic flocculation and combustion characteristics of coal(ELSEVIER, 2015) Duzyol, S.; Sensogut, C.The hydrophobic flocculation of the lignite obtained from the Ermenek region was investigated under the different operating parameters such as pH, sodium silicate concentration and kerosene concentration in the present work. Determination of combustible recovery, ash content and zeta potential values were utilized in order to make sense of the hydrophobic flocculation behavior. To specify indirectly the hydrophobicity degree of the coal, contact angle measurements were performed on the flocks obtained from the experiments. The combustion characteristics of coal such as thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA), ignition temperature, and peak temperature were analyzed and correlated with the hydrophobic flocculation. In consequence, optimum pH value was determined as to be 4; optimum sodium silicate and kerosene concentration were also ascertained as to be 1 kg/t and 16 kg/t, respectively. When experimental conditions were set up optimally, the flocks were obtained with combustible recovery of 90% and ash content of 9.8%. The strong correlation was observed between the hydrophobic flocculation results and ignition temperatures and peak temperatures acquired from the DTGA curves. The surface tension of solution, however, showed no remarkable changing. It was confirmed that the contact angle values ranged from 114 degrees to 130 degrees and the surfaces were highly hydrophobic. (C) 2015 Elsevier B.V. All rights reserved.Öğe Turbidity removal of fine coal-water suspension by flocculation using Taguchi (L-16) experimental design(TAYLOR & FRANCIS INC, 2018) Duzyol, S.Taguchi method is rather practical way for setting the best combination of different variables for various parameters in such phenomenon requiring excessive number of experiments. In this study, a series of flocculation experiments were performed using Taguchi (L-16) experimental design to determine the optimum conditions for the turbidity removal from fine coal suspensions. The effects of some controllable factors on the turbidity removal were evaluated by effective flocculation recovery via analysis of mean statistical approach and the percentage contributions of each parameters were also defined using analysis of variance statistical approach. The most influential factor was determined as the polymer concentration with a contribution of 47.831%. The optimum conditions were ascertained as pH=7, stirring speed of 500rpm, polymer concentration of 2mg/L, flocculation time of 3min, and polymer type of 934SH.
