A kinetic study of the reaction between hot metal and soda ash

在用纯碱预处理铁水过程中，纯碱与碳的反应往往作为副反应进行，影响铁水脱磷、脱硫的进程。然而，这些反应之间的相互关系还没有得到充分的理解，从反应动力学的观点，在本工作中，碳和二氧化硅对脱磷率的铁水苏打灰进行了研究，通过检查在运行过程中的金属和气体的组成的变化。结果表明：纯碱与铁碳熔体反应时，纯碱部分被还原为Na蒸气，生成的气体中仅含CO;铁磷碳熔体优先脱磷，在金属磷含量降至0.05%后开始脱碳。当熔剂量从5 g增加到9 g时，脱磷率增加，当熔剂量再增加到15 g时，脱碳率增加，而脱磷过程中放出的气体中含有4 ~ 6%<CO_2>和50%左右的CO，由此计算出氧分压&lt;10^（-11）&gt; atm，当熔剂中加入SiO2时<CO_2>，气体中含有40 ~ 60%和几个百分点的CO。结果表明，纯碱与二氧化硅反应速度过快，<CO_2>熔剂中产生的气体不能用于铁水脱磷脱碳。

In the pretreatment of hot metal by soda ash, the reaction between soda and carbon always proceeds as a side reaction and influences the progress of dephosphorization and desulfurization of hot metal. However, the corelation between these reactions has not been sufficiently understood from the viewpoint of reaction kinetics.In the present work, the effects of carbon and silica on the rate of dephosphorization of hot metal by soda ash were investigated by examining the change in the composition of both the metal and the gas evolved during a run. The results obtained are as follows:In the reaction between soda ash and Fe-C melt, soda ash was reduced partly to Na vapor and the gases evolved contained only CO.For Fe-P-C melts, the dephosphorization proceeded preferentially and the decarburization began after the metal phosphorus content decreased down to 0.05%. The increase in the flux amount from 5 g to 9 g resulted in the increased dephosphorization, but further increase in the flux amount to 15 g produced only the increase of the rate of decarburization.While, the gases evolved during the period of dephosphorization contained 4 to 6 % <CO_2> and about 50% CO, from which the partial pressure of oxygen was calculated to be <10^(-11)> atm.When silica was added to the flux, 40 to 60% of <CO_2> and several percent of CO were detected in the gases. This result showed that the reaction between soda ash and silica proceeded so fast and <CO_2> gas produced in the bulk of flux was not utilized for the dephosphorization and the decarburization of hot metal.