Why is flotation used

See Surface Active Substances. Other reagents used in flotation are frothers to promote a smaller bubble size and a more stable froth, and modifiers or conditioners to adjust the pH of the suspension and assist attachment of bubbles to specific particle species in the suspension.

Conditioners used include coagulants and polymer flocculants. All flotation systems require a source of gas bubbles. In natural flotation , release of gas in the form of bubbles from, for example, a fermentation is the cause of scum at the surface of the liquid. Aided flotation is a natural flotation improved by blowing air bubbles into the suspension, and is useful for the separation of greases dispersed in a turbid liquid.

In most process industry flotations, the bubbles are formed by three main techniques: i mechanically, using an agitator combined with an air injection system or by pumping the air through a porous plate or nozzle, to form bubbles that measure 0. As general purpose liquid-solid separation technologies, the two flotation techniques which have found increasing value in recent years are dissolved air DAF and electroflotation EF. EF has the advantage that no pressurized recycle is required; the flow handled by the EP unit comprises the feed only.

The recycle employed with DAE increases the flow into the unit. In EF there is no need for recycle pumps, compressors or saturators, but EF does require transformer-rectifier systems which can be relatively expensive.

Both DAF and EF may be used either for clarification of liquids or for thickening or concentrating of solids suspensions. The microscopic mechanisms that occur in flotation are complex, making it impossible to describe in mathematical detail or to develop fundamental design equations. According to Fuerstenau , most flotation systems with a high degree of turbulence approximate to perfect mixers and the recovery of solids is then given by:. Nauk SSSR , Garrels and C. Peters in Trends in Electrochemistry , J.

Bockris, D. Rand, and B. Welch, eds. Gardner and R. Woods, J. Woods, Int. Heyes and W. Trahar, Int. Chander and D. AIME , 62 Tolun and J. Kitchener, Trans. Kowal and A. Pomianowski, J. Fuerstenau, J. Janetski, S. Woodburn, and R. Woods, Aust. Ahmed, Int. Process , 5 , Hamilton and R. Woods, in Flotation—A. Sato, Econ. Nickel, J. Ross, and M.

Thornber, Econ. Tributsch and H. Gerischer, J. Majima and E. II, Institut Mekhanobr. Biegler, D. Rand, and R. Aston, D. Woods, unpublished work. Woods, in Trends in Electrochemistry , J. Rand, J. Tributsch, Ber. Jones and J. Woodcock, Int. Liu D, Peng Y Reducing the entrainment of clay minerals in flotation using tap and saline water.

Min Metallurgical Process J — J Mater ResTechnol — Marcelja S Selective coalescence of bubbles in simple electrolytes. J Phys Chem B — Coal Preparation — Miner Metall Process Mohanty MK Screen bowl centrifuge dewatering process: a parameteric study. Phys Sep Sci Eng —9. Navarro P, Alguacil FJ Adsorption of antimony and arsenic from a copper electrorefining solution onto activated carbon. Sep Purif Technol — Nature — Paulson O, Pugh RJ Flotation of inherently hydrophobic particles in aqueous solutions of inorganic electrolytes.

Keith pentlandite ore in de-ionised and saline water. Journal of China Coal Society — Peters NE, Meybeck M Water quality degradation effects on freshwater availability: impacts of human activities.

Water Int — Environ Sci Technol Seke MD, Pistorius PC Effect of cuprous cyanide, dry and wet milling on the selective flotation of galena and sphalerite. Shengo L, Gaydardzhiev S, Kalenga N a Effects of process water recycling during flotation of copper and cobalt oxidised ores from Luiswishi deposit in the Democratic Republic of Congo.

Desalin Water Treat — Shengo LM, Gaydardzhiev S, Kalenga NM b Malachite and heterogenite behavior during the locked-cycle recycling of process water in flotation of copper-cobalt oxide ores. Aiche J — Stirbanovic Z, Miljanovic I, Markovic Z Application of rough set theory for choosing optimal location for flotation tailings dump. Arch Min Sci — Subrahmanyam TV, Forssberg E Froth stability, particle entrainment and drainage in flotation — a review.

Torrisi C, Trotta P Sustainable water use at olympic dam. Verma S, Klima MS Evaluation of a pilot-scale, plate-and-frame filter press for dewatering thickener underflow slurries from bituminous coal-cleaning plants. Int J Coal Prep Util — Chem Eng Sci — Wang B, Peng Y The behaviour of mineral matter in fine coal flotation using saline water. Fuel — Wang B, Peng Y The effect of saline water on mineral flotation — a critical review. Miner Eng 66—— Wang B, Peng Y, Vink S Effect of saline water on the flotation of fine and coarse coal particles in the presence of clay minerals.

Miner Eng 96—— Wei T, Peng Y, Vink S The joint action of saline water and flotation reagents in stabilizing froth in coal flotation. Nonferrous Metals — J China Coal Soc — Yang Y, Li Y, Zhang Y-m, Liang D-w Applying hybrid coagulants and polyacrylamide flocculants in the treatment of high-phosphorus hematite flotation wastewater HHFW : optimization through response surface methodology. Zhang M, Xu N, Peng Y b The entrainment of kaolinite particles in copper and gold flotation using fresh water and sea water.

J Environ Sci — Download references. This study received financial supports from the National Natural Science Foundation of China under the projects of and You can also search for this author in PubMed Google Scholar.

Correspondence to Shaoxian Song. Reprints and Permissions. Li, Y. Download citation. Received : 06 September Accepted : 11 September Published : 27 September