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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 Correlation of the Particle Size Distribution Parameters with Sieving Rate Constant(TAYLOR & FRANCIS INC, 2014) Yekeler, M.; Ciftci, M.; Ulusoy, U.; Ozkan, A.Controlling the particle size distribution (PSD) of raw materials, intermediates, and end products is very critical to the success of the powder technology related processes. This study presents the evaluation of the sieving characteristics of some industrial minerals, namely, quartz, talc, and barite, and the establishment of possible correlations between the PSD and kinetics parameters. PSD of the -600 mu m fractions of quartz, talc, and barite minerals were plotted in Schuhmann mathematical approach. The size modulus (k(s)) and distribution modulus ((s)) were obtained for each mineral. Then, sieving kinetics study was carried out for each mineral to determine optimum sieving time and sieving rate constant (k(k)). Further, the size distribution parameters were correlated with the sieving rate constant values for those minerals. While distribution modulus ((s)) increases, size modulus (k(s)), and average sieving rate constant values (k(k)) decrease. The correlations were found to be k(s)=-293.52(s)+730.87 and k(k)=-0.0041(s)+0.0454. The results showed that near-mesh particles play important role in the overall kinetic process.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 Hydrophobic flocculation characteristics of calcite and effects of some inorganic dispersants(NATL INST SCIENCE COMMUNICATION, 2006) Ucbeyiay, H.; Ozkan, A.Hydrophobic flocculation characteristics of calcite mineral were investigated using sodium dodecyl sulphate (SDS) and Acro 845. Calcite suspensions could be flocculated by these anionic surfactants in the pH range of 9.3-11.5. Especially SDS was more effective on the calcite suspensions at pH values lower than 10.5. The flocculation of calcite with SDS and Aero 845 increased rapidly with increasing surfactant concentration. However, it started to decrease at concentrations higher than 30 mg/L for Aero 845 and 50 mg/L for SDS. It was found that the maximum aggregation degree of calcite particles could be achieved with a stirring speed of 500 rpm and a flocculation time of 3 min. The effects of sodium silicate, sodium polyphosphate and sodium phosphate, used as inorganic dispersants, on the flocculation of calcite were also studied. In the presence of sodium silicate and sodium polyphosphate, the flocculation power values obtained with both surfactants decreased with increasing dispersant concentration till approximately 0.5 and 1 g/L concentrations, respectively. Also, the flocculation of calcite with Aero 845 and SDS decreased towards 0.5 and 1 g/L concentrations of sodium phosphate, respectively. At higher dispersant concentrations, these power values remained relatively constant for sodium silicate, and different effects were also observed for other dispersants depending on surfactant type used in the experiments. In addition, it was found that sodium silicate was more effective to disperse the calcite suspensions with SDS and Aero 845.Öğe Hydrophobic flocculation of talc with kerosene and effects of anionic surfactants(TAYLOR & FRANCIS INC, 2016) Ozkan, A.; Dudnik, V.; Esmeli, K.The variation of the hydrophobic flocculation behavior of talc mineral with pH, kerosene concentration, stirring speed, flocculation, and settling times was investigated. The experimental studies showed that the flocculation of talc suspension increased to a particular point with increasing kerosene concentration and thereafter decreased slightly. Also, the flocculation with kerosene was not much affected by the pH changes of the suspension. On the other hand, sodium oleate, sodium dodecyl sulfate (SDS), and Aero 801 used as anionic surfactant in conjunction with kerosene provided significant increases in the flocculation of talc, and depends on increasing surface hydrophobicity of the particles. Especially, in the presence of sodium oleate along with kerosene, the talc suspension could be flocculated with a recovery of 95%. Consequently, the enhancement with nonpolar oil was more significant for the hydrophobic flocculation of talc suspension promoted by long hydrocarbon chain surfactant (sodium oleate) than short hydrocarbon chain surfactants (SDS and Aero 801).Öğe Investigation of coagulation and electrokinetic behaviors of clinoptilolite suspension with multivalent cations(TAYLOR & FRANCIS INC, 2018) Ozkan, A.; Sener, A. G.; Ucbeyiay, H.This paper presents the results of investigations concerning the influence of magnesium, copper, aluminum and ferric cations on the coagulation and electrokinetic behaviors of clinoptilolite suspension. While clinoptilolite exhibited a negative surface charge over a broad pH range and had no isoelectric point (iep), especially the trivalent ions strongly changed the sign and magnitude of the zeta potential of the mineral depending on pH and cation concentration. The coagulation of clinoptilolite particles with these metal cations also showed sharp dependences on pH and cation concentration. That is, the coagulation process significantly took place in the pH and concentration ranges in which metal hydroxides existed in the suspension. Moreover, the coagulation behavior of clinoptilolite at pH values below the iep of metal hydroxides was usually consistent with its zeta potential variation, indicating a coagulation process by the charge neutralization mechanism. However, at pH values larger than the iep of these hydroxides, sweep coagulation of clinoptilolite suspension occurred and a clear correlation between surface charge and the onset of coagulation was not determined.Öğe Investigation of shear flocculation behaviors of colemanite with some anionic surfactants and inorganic salts(ELSEVIER SCIENCE BV, 2011) Sahinkaya, H. Ucbeyiay; Ozkan, A.The variations of shear flocculation of colemanite mineral with sodium oleate and sodium dodecyl sulfate (SDS) as anionic surfactants with suspension pH, surfactant concentration, stirring speed, and flocculation time have been investigated. It was determined that sodium oleate was more effective in the flocculation than SDS and the colemanite particles could be flocculated by oleate in the broad pH range. Also, a stirring speed of 500 rpm and a flocculation time of 3 min were required to achieve the maximum flocculation degree of colemanite particles. The effects of magnesium, barium, aluminum, and ferric chlorides as inorganic salts on the shear flocculation of colemanite suspension were also studied. In the presence of these cations, the flocculation degrees of colemanite suspension reached high values at particular conditions. However, some differences in the behavior of flocculation of colemanite mineral were observed depending on pH, cation concentration, type of surfactant and inorganic salt. (C) 2011 Elsevier B.V. All rights reserved.Öğe Kinetics of fine wet grinding of zeolite in a steel ball mill in comparison to dry grinding(ELSEVIER SCIENCE BV, 2009) Ozkan, A.; Yekeler, M.; Calkaya, M.Batch wet grinding of zeolite was studied with emphasis on a kinetic study in a laboratory size steel ball mill of 200 mm diameter. The breakage parameters were determined by using the single sized feed fractions of -850+600 mu m, -600+425 mu m and -425+300 mu m for the zeolite samples. The S(i) (specific rate of breakage) and B(ij) (primary breakage distribution) values were obtained for those feed size fractions in order to predict the product size distributions by Simulation for comparison to the experimental data. The specific rates of breakage values for wet grinding in the first-order breakage region were higher than the dry values reported previously by a factor 1.7 at the same experimental conditions, but the primary breakage distribution (B(ij)) values were approximately the same. The simulations of the product size distributions of zeolite were in good agreement with the experimental data using a standard ball mill simulation program. The wet grinding of zeolite was subjected to slowing-down effect in the mill at 2 min of grinding, corresponding to an 80% passing size of about 400 mu m. On the other hand. the slowing down effect in the dry grinding of zeolite was also seen at 4 min of grinding. In addition, effects of some operational parameters on dry and wet grinding of zeolite were determined by simulation using the breakage parameters obtained experimentally. (C) 2008 Elsevier B.V. All rights reserved.Öğe Selective flocculation of celestite from celestite-calcite fines(NATL INST SCIENCE COMMUNICATION-NISCAIR, 2008) Ozkan, A.; Uebeyiay, H.In this study, selective hydrophobic flocculation of celestite with sodium dodecyl sulphate (SDS) from the mixtures of celestite and calcite was investigated using sodium silicate as inorganic dispersant. Prior to the selective flocculation process, the critical surface tension of wetting (gamma(c)) values of these minerals were determined as a function of SDS concentration. A significant difference between the gamma(c) values of celestite and calcite was found at concentrations around 20 mg/dm(3), indicating that celestite particles can be selectively floccuated from the mixtures at these concentrations. Then, the effects of pH, dispesant concentration, flocculation and settling times on the selective flocculation of celestite mineral were studied. Experiments carried out with sodium silicate at optimum conditions yielded a concentrate, which is flocculated material, assaying 85% SrSO(4) with a recovery 90% and seperation index of 0.90 from a mixture containing 50% SrSO(4).Öğe Two-stage shear flocculation for enrichment of fine boron ore containing colemanite(ELSEVIER SCIENCE BV, 2014) Ucbeyiay, H.; Ozkan, A.The enrichment of fine boron ore containing colemanite mineral was investigated using shear flocculation, two-stage shear flocculation, column flotation and floc flotation techniques. In these fine particle processing methods, sodium dodecyl sulfate (SDS) and Aero 801 were used as surfactant for colemanite. Also, sodium pyrophosphate and sodium hexametaphosphate were employed to improve the selectivity of the processes. The highest grade of the colemanite concentrate was obtained with two-stage shear flocculation method using Aero 801 and sodium hexametaphosphate. Under the optimum conditions, a concentrate of 38.65% B2O3 could be recovered by two-stage shear flocculation from the ore containing 26.98% B2O3. (C) 2014 Elsevier B.V. All rights reserved.
