Mass transfer in a bubble-agitated liquid-liquid system with applications to metal purification by slagging

Mass transfer coefficients between a mercury layer and an aqueous layer agitated by gas bubbles were measured by a polarographic method. The effects of gas rate, vessel size, and sparge-tube diameter were studied. The Schmidt number of the aqueous phase was varied by the use of sugar solutions. The data are well represented by N/sub Sh/ = 1.33N/sub RE/ /sup 0/ /sup 70/N/sub Sc/sup 1/3/. The effect of gas sparging on the rate of mass transfer was reviewed for slagging operations involving the purification and recycle of metals. Natural convection may cause rapid mass transfer in small systems, such as ladles, whereas in large systems such as hearth furnaces gas sparging should significantly increase the rate of mass transfer.