Kinetic studies have been made on the rate of reaction between molten slag and metal with gas-injection stirring. The explored reaction is oxidation of Si in molten Cu by FeO in a Li
2O-SiO
2-Al
2O
3-FeO slag 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,
kSi', are calculated from the kinetic data. Relations between
kSi' and experimental conditions (gas flow-rate,
Vg ; metal depth,
hM; slag depth,
hsl ; crucible diameter,
dc) have been investigated.
kSi' is found to increase generally with increasing
Vg. The dependence of
kSi' on the gas flow-rate varies at certain gas flow-rates denoted by
Vg* and
Vg**.In the low
Vg range (
Vg<
Vg* : Region
I),
kSi' is proportional to (
Vg/
dc2)
1/2. In the medium
Vg range (
Vg* <
Vg<
Vg** : Region
II), the effect of the increase in gas flow-rate on
kSi' is cosiderably smaller than in Region
I. In the high
Vg range (
Vg>
Vg**: Region
III), the extent of the increase in
kSi' with
Vg increases again. It is also found that
kSi' increases with metal depth,
hM, below a transitional depth,
hM*. Above the transitional metal depth
hM*,
kSi' becomes independent of
hM. Examinations have been performed of the influence of slag depth,
hsl, on
kSi' in Regions
I and
II. In Region
I,
kSi' is independent of
hsl. In Region
II,
kSi' decreases with the decrease of slag depth.
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