Investigation of the Influence of Effective Parameters on Bubble Size Distribution in a Mechanical Flotation Cell by Image Analysis Method Modification

Document Type : Research Note


Mining Engineering Department, Imam Khomeiny International University, Gazvin, I.R. IRAN


One of the effective factors on the efficiency of the flotation process, is bubble size distribution. Bubble size influences the bubble/particle collision, attachment and detachment probability. In this paper, size distribution of bubbles produced in a laboratory mechanical flotation cell, has been investigated by the direct image analysis method. In addition, effect of some important parameters such as frother concentration, pH value and temperature on bubbles size have been studied. In order to sample bubbles for imaging, bubble viewer with a viewing chamber was designed and made. Images were analyzed using Image J Ver. 1.44 software. To reduce number of bubbles in imaging zone and minimizing bubble overlap, the tube diameter was chosen small as much as possible so that quality and accuracy of image analysis were improved. In addition, by covering side walls of viewing chamber, light entrance from these walls was prevented and images quality was enhanced. Moreover, by photography field depth adjustment and also applying suitable lens, existing problems in previous studies such as bubble overlap and error induced by perspective were improved. To minimize bubble diameter standard deviation, 200 images per experiment were taken and some of them were randomly chosen analyzed. Study of frother effect on bubble size showed that with increase of frother concentration from 10 ppm to 60 ppm, Sauter diameter (d32) of bubbles decreased from 910 mm to 706 mm. with increasing pH from 4 to 10.4, in sync with increase of zeta potential absolute value, d32 of bubbles decreased from 1020 mm to 754 mm and bubble size distribution curve became similar to normal distribution. Furthermore, increase of temperature from 10 °C to 47 °C, resulted enlargement of Sauter diameter of bubbles from 611 mm to 830 mm.


Main Subjects

[1] Cho Y. S., "Effect of Flotation Frothers on Bubble Size and Foam Stability", Master of Science Dissertation, The University of British Colombia, Canada, Vancouver (2002).
[2] Grainer A., Bubble Generation in Froth Flotation Machines, Transactions of the Institution of Mining and Metallurgy, 79: 15–22 (1970).
[4] Jung S.Y., Park H.W., Lee S.J., Simultaneous Measurement of Bubble Size, Velocity and Void Fraction in Two-Phase Bubbly Flows with Time-Resolved X-Ray Imaging, Journal of Synchrotron Radiation, 21(2): 424-429 (2014).
[5] Brian G.T., Alex D., Hua B., Behavior of Argon Bubbles during Continuous Casting of Steel, "80th Steelmaking Conference",Chicago, 13-16 (1997).
[6] Nikhitha B., Deekshith P., Santhosh Kumar G., A Review of Methodologies to Determine Bubble Diameter and Bubble Velocity, International Journal of Scientific and Research Publications, 2(9):11-20 (2012).
[7] Pandit A.B., Varley J., Thorpe R.B., Davidson J.F., Measurement of BubbleSize Distribution - an Acoustic Technique, Chem Eng Sci, 47:1079-1089 ( 1992).
[8] Chen F., Gomez C.O., Finch J.A., Technical Note: Bubble Size Measurement in Flotation Machines, Minerals Engincering, 14(4):427-432 (2001).
[9] Hernandez-Aguilar J.R., Gomez C.O., Finch, J.A., A Technique for the DirectMeasurement of Bubble Size Distributions in Industrial Flotation Cells, "Proceedings  of the 34th Annual Meeting of the Canadian Mineral Processors", 389-402 (2002).
[10] Azgomi F., Gomez C.O., Finch J.A., Correspondence of Gas Holdup and Bubble Size
in Presence of Different Frothers
, Int. J. Miner. Process., 83: 1–11 (2007).
[11] Finch J.A., Nesset J.E., Acuña C., Role of Frother on Bubble Production and Behaviour
in Flotation,
Minerals Engineering 21: 949–957 (2008).
[12] Aldrich C., Feng D., The Effect of Frothers on Bubble Size Distributions in Flotation  Pulp Phase And  Surface Froths, Minerals  Engineering, 13(10-1): 1049-1057 (2000).
[13] Sweet C., van Hoogstraten J., Harris M., Laskowski J.S., The Effect of Frothers on Bubble Size and Frothability of Aqueous Solutions, Minerals Engineering, 21: 949–957 Series on Fundamental in Mineral Processing. The Metallurgical Society of CIM, 235–246 (1997).
[14] Gupta A. K., Banerjee P.K., Mishra, A.,  Satish, P., Effect of Alcohol and Polyglycol Ether Frothers on Foam Stability, Bubble Size and Coal Flotation, Int. J. Miner. Process., 82: 126-137 (2006).
[15] Moyo P., "Characterization of Frothers By Water Carrying Rate", McGill University Montreal, Canada, 978-0-494-22658-2 (2005).
[17] Nesset J.E., Zhang W., Finch J A., Benchmarking Tool for Assessing flotation Cell Performance, “Proceedings of the 44th Annual Meeting of Canadian Mineral Processors (CIM)", Ottawa, Canada, 17−19 January, 183−209 (2012).
[18] Calgaroto S., Wilberg K.Q., Rubio J., On the Nanobubbles Interfacial Properties and Future Applications in Flotation, Minerals Engineering, 60, 33-40 (2014). 
[19] Elmahdy A.M., Mirnezami M., Finch J.A., Zeta Potential of Air Bubbles in Presence of Frothers, Int. J. Miner. Process., 89, 40–43 (2008).
[20] Wu Ch., Nesset K., Masliyah J., Xu Zh., Generation and Characterization of Submicron Size Bubbles, Advances in Colloid and Interface Science 19(2): 123–132 (2012).
[21] Conway B.E., Ion hydration near air/water interfaces and the structure of liquid surfaces, Electroanal J., Chem.,  65:491-504 (1975).
[22] Jin F., Li J., Ye X., Wu Ch., Effects of pH and Ionic Strength on the Stability of Nanobubbles in Aqueous Solutions of a-Cyclodextrin, J. Phys. Chem., 111:11745-11749 (2007).
]23[ احمدی، رحمان؛ خدادادی، احمد؛ عبداللهی، محمود؛ فلوتاسیون نرمه‌های کالکوپیریت در حضور نانوحباب‌های تولید شده با روش کاویتاسیون هیدرودینامیکی، نشریه شیمی و مهندسی شیمی ایران، (4)32: 81 تا 91 (1392).
[24] Phan C. M., Surface Potential of Methyl Isobutyl Carbinol Adsorption Layer at the Air/Water Interface, The Journal of Physical Chemistry, 116: 980–986 (2012).
[25] Zhang W.,  Nesset J. E., Finch J.A., Bubble Size as a Function of Some Situational Variables
in Mechanical Flotation Machines
, J. Cent. South Univ., 21: 720−727 (2014).
[26] Najafi A., Drelich J., Yeung A., Xu Zh., Masliyah J., A Novel Method of Measuring Electrophoretic Mobility of Gas Bubbles, Journal of Colloid and Interface Science, 308: 344–350 (2007).
[27] Garcia, H.E., Gordon, L.I., Limnol, J., Oxygen solubility in seawater: Better fitting equations, Limnology and Oceanography, Oceanogr, 37: 1307–1312 (1992).
[28] Hamme R.C., Emerson S.R., The solubility of neon, nitrogen and argon in distilled water and seawater, Deep-Sea Res. Part I 51: 1517–1528 (2004).
]29[ احمدی، رحمان، "فلوتاسیون نرمه‌ها از باطله‌های معدنی با تلفیقی از نانو- میکروحباب‌ها"، پایان نامه دکتری، دانشگاه تربیت مدرس، دانشکده فنی و مهندسی (2013).
[30] Maoming F., "Picobubble Enhanced Flotation of Coarse Phosphate Particles", Ph.D. dissertation, The University of Kentucky, College of Engineering (2010).
[31] Zhang X. H., Li, Gang, W., Zhang X. D., Hu J., Effect of Temperature on the Morphology of Nanobubbles at Mica/Water Interface, Chinese Physics, 14(9): 1009-1963 (2005).