Absorption Rate of Oxygen Jetted into Molten Metal

Abstract

A study was made on the absorption of oxygen jetted into molten silver to clarify the mechanism of interact ion between a gas jet and molten metal. At 1050°C preheated oxygen gas was blown on to molten silver of 230g through an alumina nozzle of 1mm in diameter. The oxygen content in themelt was measured continuously by the solid electrolyte galvanic cell. The oxygen flow rate was 1-12Nl/min and the height of the nozzle from the melt surface was -10-+20mm. The critical condition required to produce a homogeneous bulk liquid concentration was expressed in terms of the depth of the cavity. At low jet momentums a stable cavity was produced. As the jet momentum increased, the cavity became deeper, and bubbles and liquid droplets were formed, resulting in an abrupt increase of the absorption rate. The rate was described by the ordinary equation of mass transfer except for the range of low oxygen concentration of the melt. The apparent rate constant at high jet momentums was correlated to the jetting conditions, by introducing a factor characterizing jet steepness.