Model studies have been made on the rate of mass transfer between molten slag and metal with gas injection stirring. A Li
2O-SiO
2Al
2O
3 slag-molten Cu reaction system for Si oxidation has been selected as the model reaction system. The explored reaction is oxidation of Si by FeO, taking place under the condition of rate-controlling by Si transport in the metal phase. Kinetic experiments were done at 1250°C. The slag-metal bath was stirred by Ar gas injected through a nozzle located at the crucible bottom. The apparent metal-side mass transfer coefficients of Si, k'
Si, are calculated from the rate data. Relations between k'
Si and experimental conditions (gas flow rate, V
g; metal depth, h
M; crucible diameter, d
c) have been investigated.
It is found that the dependence of k'
Si on the gas flow rate varies at certain gas flow rates denoted by V
*g and V
**g. In the low V
g range (V
g<V
*g), k'
Si is proportional to (V
g/d
2c). In the medium V
g range (V
*g<V
g< V
**g), k'
Si increases only slightly with increasing V
g. In the high V
g range (V
g>V
**g), the extent of the increase in k'
Si with V
g increases again. It is also found that k'
Si increases with metal depth, h
M, below a transitional depth h
*M. When h
M>h
*M, k'
Si becomes independent of h
M.
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