Deoxidatlon rate of copper droplet levitated in Ar-H2 gas stream |
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Authors: | Y Fukunaka K Tamura N Taguchi Z Asaki |
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Affiliation: | (1) Department of Metallurgy, Kyoto University, 606 Kyoto, Japan;(2) Sumitomo Life Insurance Company Ltd., USA |
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Abstract: | Levitated copper droplets, 5 mm in diameter with initial oxygen contents of 0.036 to 1.9 wt pct, were deoxidized at about
1970 K in an Ar-H2 gas stream. The Ar-H2 gas mixture having hydrogen partial pressure less than 4 kPa was introduced into a silica reaction tube of 11-mm ID at gas
flow rates up to 2 x 10-4 Nm3s-1. The effects of initial oxygen content of the droplets, hydrogen partial pressure, and gas flow rate on the deoxidation process
were examined. A mixed control model for the deoxidation rate involving both gas and liquid film mass-transfer resistances
was combined with a thermodynamic relationship for the dissolved species in molten copper. The value of 2 × 10-4 m 73x00D7; s-1 was assigned to the liquid film mass-transfer coefficient of dissolved oxygen throughout all experimental conditions. Under
the experimental conditions of low initial oxygen content and high hydrogen partial pressure, the liquid film mass-transfer
resistance was significant. When a droplet of high initial oxygen content was deoxidized, transition phenomena from gas to
liquid film mass-transfer control were noticed in the later stage of reaction. It was deduced from the present model that
the accumulation of dissolved hydrogen was indispensable to these phenomena.
Formerly Student |
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