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Öğe Effect of chloride salt Ions onto coal flotation based on contact angle and bubble-particle attachment time(2022) Özkan, Şafak Gökhan; Güngören, Can; Baktarhan, Yasin; Özdemir, Orhan; Şahpaz, Orhan; Kurşun, İlginThis study was aimed to reveal the effect of K+, Na+, Ca2+, and Mg2+ ions on the bubble-particle interactions of high-rank coal with contact angle and bubble-particle attachment time studies. The results for the contact angle experiments indicated that the contact angle of the coal, which was 62° in the absence of ions, increased slightly in the presence of mono- and divalent ions and reached a maximum (67°) in the presence of 1?10-1 mol/dm3 Mg2+, and the effect of K+ ions on the contact angle was minimal. Furthermore, the results for the bubble-particle attachment time experiments showed that the bubble-particle attachment time of coal, which was measured as 4.5 ms in the absence of ions, decreased as a function of ion concentration from 1?10-2 mol/dm3 to 1 mol/dm3. While the bubble-particle attachment times of coal particles in the presence of K+/Na+ and Ca2+/Mg2+ at low concentrations were around 2-3 ms and 1-2 ms, respectively, the increase in the concentration slightly changed the attachment time which decreased to less than 1 ms except for K+ ions. Overall, it can be concluded from this study that the effect of these dissolved ions in water was more prominent on the bubble-particle attachment time of the coal particles rather than the contact angle which showed no significant change. Also, the specific ion effect was determined as “Mg2+ > Ca2+ > Na+ > K+” in terms of the bubble-particle interactions in the presence of these ions.Öğe Effect of conventional and microwave thermal treatments on floatability of low- and high-rank lignites(Energy Sources Part A-Recovery Utilization and Environmental Effects, 2020) Özkan, Şafak Gökhan; Baktarhan, Yasin; Demir, İsmail; Güngören, CanThermal treatment is one of the well-known methods used before froth flotation to remove the polar groups from coal surfaces to make them more hydrophobic. In this study, the effect of conventional and microwave thermal treatments on the wettability of low and high-rank lignite was investigated using flotation experiments, zeta potential, and bubble-particle attachment time measurements, as well as hydrophilicity index analyses. The results showed that both of the thermal treatments increased hydrophobicity, and therefore floatability of the coal samples. The optimum results were achieved with conventional and microwave thermal treatment for the low and high-rank coals, respectively.Öğe Enhancement of galena-potassium ethyl xanthate flotation system by low power ultrasound(Elsevier, 2020) Güngören, Can; Baktarhan, Yasin; Demir, Ismail; Özkan, Şafak GökhanThe objective of this study is to investigate the improvement possibilities of the floatability of galena with ultrasonic application in the presence of potassium ethyl xanthate (KEX). For this purpose, micro-flotation experiments were carried out in addition to surface chemistry studies including zeta potential, contact angle, and bubble-particle attachment time measurements at various ultrasonic power levels and conditioning time. The results showed that, the maximum micro-flotation recovery of 77.5% was obtained with 30 W ultrasound power and 2 min conditioning time. In addition, more negative zeta potential values were obtained with ultrasound as well as higher contact angle and lower bubble-particle attachment time, which indicated the increased hydrophobicity of galena with ultrasound.Öğe Ultrasound supported flocculation of borate tailings with differently charged flocculants(Journal of Boron, 2021) Özkan, Şafak Gökhan; Demir, İsmail; Güngören, Can; Baktarhan, Yasin; Yücel, Melike; Çinku, İlgin; Kurşun, İlginMining activities are followed by mineral processing and wet beneficiation methods which generate a significant amount of tailings. Slime fractions are discharged to the tailing ponds with associated process water and this causes storage and disposal difficulties and creates severe environmental problems. Therefore, dewatering these tailings is necessary for both economic and environmental aspects. In this study, the flocculation behaviors of the boron tailings from Agildere and Hisarcik (Turkey) were studied in the presence of anionic, cationic, and non-ionic flocculants. The results showed that the free settling condition was optimum for the Agildere sample. On the contrary, the settling rate of the Hisarcik sample increased considerably by the use of flocculants with a significant decrease in the turbidity of the suspension. Flocculation experiments indicated that the effect of the flocculant type on the flocculation of the Hisarcik sample can be generally ordered as anionic>cationic>non-ionic>no-flocculant. Furthermore, ultrasound was used as a supporting application. The results indicated that although the ultrasound application decreased the settling rate of both samples, lower sediment bed heights were obtained for the Hisarcik sample with ultrasound because of the formation of a more compact sediment bed in the presence of ultrasound.
