The reaction of CO_2 gas with hot metal was investigated based on the thermodynamic analysis and experimental results.It shows that both silicon and carbon in hot metal can be oxidized by CO_2 gas in the temperature range of 1 300-1 500 ℃.When using graphite crucible,temperature has little influence on final mass percent of carbon w[C]because of the carburization effect.Decarburization degree rises significantly with increasing gas injection rate and w[C]can be reduced to 3.2% at most when using MgO crucible.Lower temperature or higher gas injection rate is propitious to promote desilication reaction,but only 5%-10% of desilication ratio could be obtained in 20 min.The final mass percent of silicon w[Si]when using MgO crucible is lower than that when using graphite crucible.Experimental results also demonstrate that CO_2 injection has no effect on the concentration of manganese,sulfur and phosphorus in hot metal.In view of the weak oxidation ability and temperature drop of hot metal,CO_2 gas is suggested to be used as carrier gas in desilication process rather than oxidizing agent. The reaction of CO_2 gas with hot metal was investigated based on the thermodynamic analysis and experimental results. It shows that both silicon and carbon in hot metal can be oxidized by CO_2 gas in the temperature range of 1 300-1 500 ° C.When using graphite crucible, temperature has little influence on final mass percent of carbon w [C] because of the carburization effect. Decarburization degree increased significantly with increasing gas injection rate and w [C] can be reduced to 3.2% at most when using MgO crucible. temperature or higher gas injection rate is propitious to promote desilication reaction, but only 5% -10% of desilication ratio could could obtained in 20 min. final mass percent of silicon w [Si] when using MgO crucible is lower than that when using graphite crucible.Experimental results also demonstrate that CO_2 injection has no effect on the concentration of manganese, sulfur and phosphorus in hot metal. In view of the weak oxidation ability and temperature drop of hot metal, CO_2 gas is suggested to be used as carrier gas in desilication process rather than oxidizing agent.