Flotation, bubble and foam separations

Flotation, bubble and foam separations (Continued) model ... 

Separation Techniques, Academic, New York, 1972 Lemhch, Adsub-ble Methods, in li (ed.). Recent Developments in Separation Science, vol. 1, CRC Press, Cleveland, 1972, chap. 5 Grieves, Chem. Eng. J., 9, 93 (1975) Valdes-Krieg King, and Sephton, Sep. Purif Methods, 6,221 (1977) Clarke and Wilson, Foam Flotation, Marcel Deldcer, New York, 1983 and Wilson and Clarke, Bubble and Foam Separations in Waste Treatment, in Rousseau (ed.). Handbook of Separation Processes, Wiley, New York, 1987. 

As the field of bubble and foam separations grew and the literature proliferated, both general and specialized reviews appealed periodically to belp one keep track of current developments, A summary of the major review articles (not inclnding ore flotation reviews) is provided in Table 17.1-3. 

Chapters 16 and 17 examine the use of bubble and foam separation technology. Although the use of these techniques is not widespread, it is thought that the technology itself has the potential for implementation in accomplishing several important separations (e.g., protein separation). The two areas in which bubble and foam separations have been used are ore flotation, which is the primary emphasis of Chapter 16, and waste treatment, the focus of Chapter 17. 

In today s world of waste treatment, bubble and foam separations lemain lelatively little used techniques. Dissolved or induced air flotation is the most commonly used variation, havii been enqiloyed for many years in the treatment of wastewaters for the separation of suspended sc, oils, greases, fibeis, and other iow-density solids as well as fbr the thickening of activated sludge and flocculated chemical sludges. The most active commercial use was and is in ore flotation—as discussed in Chapter 16. The potential Cor the use of these separation techniques, however, is veiy high in both the areas of traditional and hazardous waste management. 

As indicated previously, froth flotation has found its major commercial use in the mining industry. Hovrever, investigations are continuing at both laboratory and pilot-scale levels to adapt bubble and foam separation technology to other useful commercial applications. It should be remembered that flotation offen several impoitant features. These include high removal efficiency, low eneigy requirements, reasonable capital investment, and comparatively low levels of maintenance and operational requirements. In addition, there is the possibility in many instances of recovery and reuse, not only of the separated substances but so of the somewhat costly surfactants. 

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