Microflotation

The slowly rising foam in a tall column can Be employed as the sorbent for continuous chromatographic separations [Talman and Rubin, Sep. Sci., 11, 509 (1976)]. Low gas rates are also employed in short columns to produce the scumlike froth of batch-operated ion flotation, microflotation, and precipitate flotation. 

As summarized by Cassell et al. (ref. 36), the early work on microflotation described the removal of bacteria and algae from water (ref. 61, 62) thereafter, further studies demonstrated that B. cereus (ref. 63), colloidal constituents of tea (ref. 64), humic acid (ref. 65), colloidal silica (ref. 66), illite (ref. 67), titanium dioxide (ref. 68), and polystyrene latex (ref. 69) could be rapidly and efficiently removed from water by microflotation. The general variety of dispersed materials which have been separated successfully... 

A.J. Rubin and E.A. Cassell, Microflotation of bacteria, Proc. 14th Southern Water Resources Pollut. Control Conf., Univ. of North Carolina, 1965. 

A.J. Rubin, E.A. Cassell, O. Henderson, J.D. Johnson and J.C. Lamb, Microflotation new low gas flow rate foam separation technique for bacteria and algae, Biotech Bioengng. 8 (1966) 135-150. 

E.A. Cassell, A.J. Rubin, H.B. LaFever and E. Matiievic, Removal of organic colloids by microflotation, Proc. 23rd Ind. Waste Conf., Purdue Univ., 1968. 

T.D. Buzzell, The chemical and physical aspects of humic acid removal by microflotation and settling, Masters Thesis,Clarkson College of Technology, 1969. 

Batch precipitate flotation with dispersed [10, 11] and dissolved [12 ]air has been carried out on a conventional laboratory set-up microflotation, adopting the procedures described earlier. The air flow rate in the flotation with dispersed air was 3 dm /h... 

Type of flow pattern(s) involved in an adsorptive bubble separation system depends on the type of process used. For example, bubble fractionation involves two-phase (gas-phase and liquid-phase) bubble flow, while solvent sublation involves multiphase bubble flow in their vertical bubble cells. Foam fractionation involves a two-phase bubble flow in the bottom bubble cell, and a two-phase froth flow in the top foam cell. However, all froth flotation processes (i.e., precipitate flotation, ion flotation, molecular flotation, ore flotation, microflotation, adsorption flotation, macroflotation, and adsorbing colloid flotation) involve multiphase bubble flow and multiphase froth flow. 

A. J. Rubin, Microflotation of bacteria. Proceedings Southern Water Resources and Pollution Control Conference, 14, 222 (1965). 

A. J. Rubin, Microflotation coagulation and foam of separation of aerobatic aerogenes, Biotechnol. Bioeng. 10, 89 (1968). 

E. Cassell and A. J. A. Rubin, Removal of organic colloids by microflotation, Proceedings of the 23rd Industrial Waste Conference, Purdue University, IN, pp. 966-977,1968. 

Morris. G.E., Eomasiero. D.. and Ralston. J., Polymer depressants at the talc-water interface Adsorption isotherm, microflotation and electrokinetic studies, Int. J. Miner. Process., SI, 211. 2002. 

It can be seen that magnesium addition to calcium oleate solution or vice versa does shift the transmission curve to lower oleate concentrations, indicating co-precipitation of calcium and magnesium oleates due to synergistic effects. Overlapping of both the curves in Fig. 4.36 is also in line with the behavior of the dolomite and francolite systems in microflotation and dissolution experiments. Simultaneous measurements of dissolved species in the supernatant of the precipitated solutions (Fig. 4.37) showed Ca and Mg levels to remain almost constant until solubility products of their oleate are reached (2 x 10 " mol/1... 

Natural surface ectivity In assoc ialion with surface-active agents Foam fractionation for example, dete[gents from aqueous solutions Ion flotation, molecular flotation, adsorbing colloid flotation for example, Sr1 +, PtiJ +, Hg2+, cyanides Fnam flotation for example, microurganisms, proteins Microflotation, colloid flotation, ultraflotation for example, particulates in wastewater, clay, microoiganisms Froth flotation of noapolar minerals for example, sulfur Froth flotation For example minerals such as silica Precipitate flotation (1st and 2nd kind) Tor example, ferric hydroxide... 

Flotation of colloidal-size colligends with the aid of surfactants under mild agitation and aeration conditions is called microflotation. This lecheique has been used recendy under laboratory conditions for removal of clays and other colloidal matter from wastewater efliuenls. It is to be noted (hat the term microflolalion also is used by those woriting on mineral flotation chemistiy to froth flotation conducted in the laboratory with 1-10 g of mineral feed. 

Chapters 10 and 11 are dedicated to nex concepts of flotation and microflotation. As a main act of these processes the formation and stability of thin liquid films are discussed in Appendix 2D. 

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