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Öğe Adsorption Kinetics of Various Frothers on Rising Bubbles of Different Sizes under Flotation Conditions(Mdpi, 2021) Batjargal, Khandjamts; Guven, Onur; Ozdemir, Orhan; Karakashev, Stoyan, I; Grozev, Nikolay A.; Boylu, Feridun; Celik, Mehmet SabriThis paper studies the effect of the type and concentration of selected frothers, the gas flowrate, and the pore size of the porous frit on the bubble sizes (Sauter mean diameter, SMD) of bubbling flow produced in a micro-flotation cell, and the determination of bubble size distribution (BSD) in the presence of the frothers. The commercial frothers polypropylene glycols (PPG 200, 400, and 600), tri propylene glycol (BTPG), triethylene glycol (BTEG), dipropylene glycol (BDPG), and Methyl Isobutyl Carbinol (MIBC) were used in the present investigation. The frother concentration varied from 1 to 1000 ppm. The flow rate varied in the range of 25 to 100 cm(3)/min. The pore sizes of the frit were selected as 10-16 mu m, 16-40 mu m, and 40-100 mu m. Each frother exhibited its own unique ability in preventing coalescence of the bubbles in the order of BTEG < BDPG < PPG 200 < MIBC < BTPG < PPG 400 < PPG 600. The factorial experiments established that the type of the frother and its concentration have a major effect on the size of the bubbles. The bubbles decreased twice their size when the frother concentration was increased from 1 ppm to 1000 ppm. The pore size of the frit is a significant factor as well. The size of the bubbles can be reduced from about 10% to about 40% by decreasing the pores from 40-100 mu m to 10-16 mu m but the level of this decrease depends on the type of the frother. The increase of the flowrate from 25 cm(3)/min to 100 cm(3)/min produced bubbles smaller by 25% to 50% for the case of BTEG, BDPG, PPG 200, MIBC, BTPG, while a minimum of the bubble sizes was reached for the case of PPG 400 and PPG 600, beyond which the bubbles enlarged their size. The BSD in the presence of PPG 600 varied around 0.3 mm, whereas BTEG gave a wider BSD which indicated that the type of frother affected the bubble production. Our analysis shows that the first group of frothers adsorbs instantly on the bubbles, once they leave the porous frit, thus reaching equilibrium. PPG 400 and PPG 600 adsorb significantly slower on the bubbles, possibly not reaching equilibrium during their resident time.Öğe Bubbling properties of frothers and collectors mix system(Oficyna Wydawnicza Politechniki Wroclawskiej, 2022) Batjargal, Khandjamts; Guven, Onur; Ozdemir, Orhan; Karakashev, Stoyan I.; Grozev, Nikolay A.; Boylu, Feridun; Celik, Mehmet SabriThis paper studies the effect of the type and concentration of selected frothers and collectors mix system on the bubble sizes (Sauter mean diameter, SMD) of bubbling flow produced in a micro flotation cell and the determination of bubble size distribution (BSD). The usage of dodecyl amine hydrochloride (DAH) collector on the critical coalescence concentration of commercial frothers PPG200, PPG400, and PPG600 was investigated in detail. The results of these studies showed that the usage of DAH decreased the CCC of these frothers. Each frother + collector mixing system exhibited its unique ability in preventing coalescence of the bubbles in the order of PPG200 < PPG400 < PPG600. The factorial experiments established that the type of the frother, collector, and their concentration had a major effect on the size of the bubbles. The BSD in the presence of PPG600 + DAH mix system resulted in a little bit wider BSD which indicated the effect of frother in mixedÖğe Correlation of Flotation Recoveries and Bubble-Particle Attachment Time for Dodecyl Ammonium Hydrochloride/Frother/Quartz Flotation System(Mdpi, 2023) Batjargal, Khandjamts; Guven, Onur; Ozdemir, Orhan; Boylu, Feridun; Pural, Yusuf Enes; Celik, Mehmet SabriRecent studies in the flotation of fine particles have necessitated new techniques and analyses for developing various strategies. Particularly, the improvements in flotation chemistry including the selection of the type of frother, collector, and other reagents have become very significant. In this study, the effect of different commercial polypropylene glycol frothers (PPG200, 400, and 600) in the presence of dodecylammonium hydrochloride (DAH) was investigated for their contribution to flotation recoveries and bubble-particle attachment time values of fine quartz minerals. Zeta potential measurements with DAH were also carried out as a function of pH and reagent concentration to justify the effect of collector usage alone on the charge of particles. A linear increase in flotation recoveries against collector concentration, e.g., 7.4% recovery at 1 x 10-5 mol/L DAH and 65.4% recovery at 1 x 10-3 mol/L DAH, was obtained. In this context, the contribution of frothers was particularly important in that a recovery of 15.91% in the absence of the frother and a modest increase to 19.70% was obtained upon the addition of PPG600 at its critical coalescence concentration (CCC) of 3 ppm. Finally, a strong correlation was found between the bubble-particle attachment time and flotation recovery as a function of collector concentration (lowest attachment time vs. highest flotation recovery). The latter correlation is very promising because bubble attachment time leads to various micro-mechanisms in flotation including bubble film thinning, bubble rupture, and induction time, and consequently, frother efficiency in the presence and absence of a collector. As a result, the experimental findings were gathered to achieve a consistent base for further fundamental studies on the application of the synergistic effect of frothers and collectors in the flotation of fine particles.Öğe Correlations for Easy Calculation of the Critical Coalescence Concentration (CCC) of Simple Frothers(Mdpi, 2020) Karakashev, Stoyan I.; Grozev, Nikolay A.; Batjargal, Khandjamts; Guven, Onur; Ozdemir, Orhan; Boylu, Feridun; Celik, Mehmet SabriCan the critical coalescence concentration (CCC) of the flotation frothers be predictable? What is the relation between their molecular structure and their CCC values? A literature survey found specific correlations between the hydrophilic-lipophilic balances (HLB) and HLB/Mw (where Mw stands for the molecular mass) of homologue series of frothers and their CCC values, but the results are invalid when the molecule's functional groups change. For this reason, 37 frothers with known values of CCC were analyzed. The CCC values of seven frothers were determined, and the rest were taken from the literature. The frothers were subdivided in homologue series with an increasing number of the carbon atoms with an account for the type and the location of the functional group, thus deriving three types of correlations lnCCC =f(HLB) applicable for: (i) alcohols; (ii) propylene glycols alkyl ethers and propylene glycols; (iii) ethylene glycols alkyl ethers. The average accuracy of these correlations between CCC and HLB is 93%.Öğe Effect of particle shape properties on selective separation of chromite from serpentine by flotation(Oficyna Wydawnicza Politechniki Wroclawskiej, 2020) Guven, Onur; Serdengecti, M. Tayhan; Tunc, Berivan; Ozdemir, Orhan; Karaagaclioglu, Ibrahim E.; Celik, Mehmet S.Although many studies have been conducted on the morphological variations and its effects on flotation recoveries of a single mineral system, a systematic study for the flotation behavior of mixtures of minerals has not dwelled much. In this study, th flotation behavior of chromite and serpentine minerals was investigated to distinguish and isolate the contribution of morphology in single and binary systems. For this purpose, the shape analyses for the minerals ground as single and mixture were performed, and their flotation behaviors determined with the micro-flotation experiments. Additionally, the zeta potential measurements were carried out in the presence of sodium oleate as a collector. The shape analysis of the ground samples showed that while the roundness values of chromite and serpentine (gangue) minerals as single were quite different, the particle shape of chromite favored serpentine in the mixture system which in turn suggested that the mineral with the high hardness value dominates the shape characteristics in binary grinding conditions. Accordingly, while the flotation characteristics of chromite in the mixture followed the same trend with the flotation of a single chromite system as a function of particle shape, almost a reverse trend was obtained for the shape and flotation of serpentine in the mixture compared to a single serpentine system. Thus, at roundness values of chromite particles from 0.797 to 0.732, the flotation recoveries of chromite in the mixture increased from 51.0% to 75.4%. On the other hand, likewise chromite, the flotation recoveries of serpentine increased from 20.0% to 37.3% proportional to the roundness range of 0.757 and 0.709. These findings in turn showed that the grinding conditions dictate the soft component to be monitored by the harder and denser component which dominates the angularity and floatability of the mixture.Öğe Experimental Procedure for the Determination of the Critical Coalescence Concentration (CCC) of Simple Frothers(Mdpi, 2020) Guven, Onur; Batjargal, Khandjamts; Ozdemir, Orhan; Karakashev, Stoyan, I; Grozev, Nikolay A.; Boylu, Feridun; Celik, Mehmet SabriIn this study, the critical coalescence concentrations (CCC) of selected commercial frother solutions, namely polypropylene glycols (PPG 200, 400, and 600), tri propylene glycol (BTPG), triethylene glycol (BTEG), dipropylene glycol (BDPG), and as a reference, methyl isobutyl carbinol (MIBC), were determined using a bubble column based on light absorption. The results for all seven frothers showed that BTEG has the worst bubble inhibiting performance, and PPG 600 has the best bubble inhibiting performance. While critical coalescence concentration (CCC) was found as 3 ppm for PPG 600, it increased to 25 ppm for BTEG. In the case of MIBC, which was the reference point, the CCC value was found as 10 ppm, which was consistent with the literature. The surface tension isotherms of the frothers were determined and analyzed with one of the latest adsorption models. The results indicated that the polypropylene glycol frothers showed more surface activity compared to alcohol or other frothers investigated. This is due to the additional reorganization of the PPG molecules on the air/water interface, thus boosting its surface activity.Öğe Frothing Performance of Frother-Collector Mixtures as Determined by Dynamic Foam Analyzer and Its Implications in Flotation(Mdpi, 2023) Batjargal, Khandjamts; Guven, Onur; Ozdemir, Orhan; Karakashev, Stoyan I. I.; Grozev, Nikolay A. A.; Boylu, Feridun; Celik, Mehmet SabriIn recent years, most of the studies have been adapted to determine the optimum conditions for the flotation of very fine minerals. In this context, besides parameters such as particle size, morphology, and pH, the effects of frother type and its concentration present a very significant role in optimizing the flotation conditions. Therefore, the effects of froth stability during flotation can be considered one of the most important issues. Considering that knowledge in mind, in this study, the foamability and froth decay rate of six frothers (PPG200, PPG400, PPG600, BTEG, BTPG, and BDPG) having different molecular weights but similar polyglycol structures were investigated. In addition, methyl isobutyl carbinol (MIBC) which is a well-known frother type in the industry was also used as a reference. Additionally, a series of tests were also performed in the presence of collectors (Dodecylamine hydrochloride, DAH, and sodium oleate, NaOL) + frother mixtures to mimic the flotation conditions. The results of these tests indicated that the bubble size became finer at even low concentrations of PPG600 and PPG400 frothers. Following that, a significant decrease in bubble size was also found for the collector + frother mixtures system regardless of the concentration of the frothers.Öğe On the frother's strength and its performance(Pergamon-Elsevier Science Ltd, 2021) Karakashev, Stoyan, I; Grozev, Nikolay A.; Ozdemir, Orhan; Batjargal, Khandjamts; Guven, Onur; Ata, Seher; Bournival, GhislainIt is a common rule that the strength of the frother is assessed by either its dynamic foamability index (DFI) or its critical coalescence concentration (CCC). The smaller the value of CCC the stronger the frother is. This general rule (CCC rule) however is superficial although being well accepted. Yet, there are critical questions about the performance of the frothers on the bubbles: 1. Are the Gibbs elasticities stemming from the different frothers equally efficient in inhibiting the bubble coalescence? 2. How the Gibbs elasticity control the mean bubble diameter for every specific frother? 3. How the CCC value of the frothers and the mean bubble diameter are related? This work raises these questions and suggests a rule based on the Gibbs elasticity performance (Gibbs elasticity rule). The performances of seven frothers (PPG 200, PPG 400, PPG 600, BDPG, BTPG, BTEG, and MIBC), whose surface tension isotherms, CCC values, bubble fraction coalescence, and Sauter mean bubble diameter vs. frother concentration were previously studied, were analyzed According to the CCC rule, these frothers follow the order of increasing strength: MIBC approximate to BTEG < BDPG < PPG 200 < BTPG < PPG 400 < PPG 600. The Gibbs elasticity rule questions what will be the bubble fraction coalescence at a certain fixed value of the Gibbs elasticity of a frother? The above mentioned frothers according to this rule follow the series of PPG 400 < BTPG approximate to BDPG < MIBC approximate to BTEG < PPG 200. Surprisingly, it was established that PPG 600 exhibits abnormal behavior, thus significantly inhibiting the bubble coalescence in a different way, not related to the Gibbs elasticity. For this reason, PPG 600 in the above series was not included. Moreover, correlations between the mean bubble diameter, the Gibbs elasticity, and the CCC value were established. Additionally, a new dimensionless parameter was developed. It estimates the strength of a frother - zeta = ln(Ks.lCH2/alpha 0). A Surprising correlation between the CCC values of 21 frothers and their zeta values was developed. Moreover, it was established a correlation allowing us to calculate the bubble fraction coalescence vs. the frother concentration if the CCC value is known.Öğe Physical restrictions of the flotation of fine particles and ways to overcome them(Oficyna Wydawnicza Politechniki Wroclawskiej, 2022) Karakashev, Stoyan, I; Grozev, Nikolay A.; Ozdemir, Orhan; Guven, Onur; Ata, Seher; Bournival, Ghislain; Batjargal, KhandjamtsThis work analyses the basic problems of the fine particles flotation and suggests new ways to overcome them. It is well accepted that the poor recovery of fine particles is due to the small collision rate between them and the bubbles due to the significant difference between their sizes. This common opinion is based on a theory, assuming in its first version a laminar regime, but later has been advanced to intermediate turbulence. It accepts that the particles are driven by the streamlines near the bubbles. In reality, the high turbulence in the flotation cells causes myriads of eddies with different sizes and speeds of the rotation driving both bubbles and particles. Yet, a theory accounting for high turbulence exists and states that the collision rate could be much higher. Therefore, we assumed that the problem consists of the low attachment efficiency of the fine particles. Basically, two problems could exist (i) to form a three-phase contact line (TPCL) the fine particle should achieve a certain minimal penetration into the bubble, requiring sufficient push force; (ii) a thin wetting film between the bubble and the particle forms, thus increasing the hydrodynamic resistance between them and making the induction time larger than the collision time. We assumed particles with contact angle theta = 80 degrees, and established a lower size flotation limit of the particles depending mostly on the size of the bubbles, with which they collide. It spans in the range of Rp = 0.16 mu m to Rp = 0.40 mu m corresponding to bubbles size range of Rb = 50 mu m to Rb = 1000 mu m. Hence, thermodynamically the particle size fraction in the range of Rp = 0.2 mu m to Rp = 2 mu m are permitted to float but with small flotation rate due to the small difference between the total push force and maximal resistance force for formation of TPCL. The larger particles approach slowly the bubbles, thus exceeding the collision time. Therefore, most possibly the cavitation of the dissolved gas is the reason for their attachment to the bubbles. To help fine particles float better, the electrostatic attraction between bubbles and particles occurred and achieved about 92% recovery of fine silica particles for about 100 sec. The procedure increased moderately their hydrophobicity from theta approximate to 27.4 degrees to theta approximate to 54.5 degrees. Electrostatic attraction between bubbles and particles with practically no increase of the hydrophobicity of the silica particles ended in 47% recovery. All this is an indication of the high collision rate of the fine particles with the bubbles. Consequently, both, an increase in the hydrophobicity and the electrostatic attraction between particles and bubbles are key for good fine particle flotation. In addition, it was shown experimentally that the capillary pressure during collision affected the attachment of the to the bubbles.
