Article

Metallurgical and Materials Transactions B

, Volume 31, Issue 5, pp 1105-1115

Some observations on the draining of CaO-SiO2-Al2O3 slag bubble films

  • C. NexhipAffiliated withthe G.K. Williams Cooperative Research Centre for Extractive Metallurgy, CSIRO Minerals
  • , S. SunAffiliated withthe G.K. Williams Cooperative Research Centre for Extractive Metallurgy, CSIRO Minerals
  • , S. JahanshahiAffiliated withthe G.K. Williams Cooperative Research Centre for Extractive Metallurgy, CSIRO Minerals

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Abstract

Fundamentals of slag foaming were investigated by withdrawing slag bubble films from pools of CaO-SiO2-Al2O3 slags using platinum wire frames in order to measure their draining rate and lifetime before rupture. Studies were carried out using a series of developed gravimetric and optical techniques. The results showed that increasing the temperature increased the rate of draining of the slag films; however, the influence of SiO2 concentration for a given slag temperature appears rather complicated. Measurements of the thickness of bubble film plateau borders as a function of time showed slag temperature to be very important in influencing their draining behavior, i.e., the activation energy for the plateau-border thinning was found to be ∼ 150 kJ/mol, very close to that required for viscous flow in the system studied (∼60 kJ/mol). A lowering of the slag surface tension by addition of surface-active oxides (such as P2O5 and Na2O) profoundly decreased the rate of draining of the films, irrespective of the slag temperature.