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用热失重法及通过渣-金界面反应研究了含碳铬矿球团及熔渣中铬氧化物的还原速度。含碳铬矿球团还原速度的限制环节为CO在铬矿表面上的析碳反应和碳通过产物层向内部的扩散,通过动力学分析及实验结果得出还原速度与温度和球团矿粉粒度的关系式。在1200～1300℃,求得碳的扩散系数为10~(-12)～10~(-11)cm~2/s,析碳反应速度常数为10~(-7)～10~(-6)cm/s。球团中添加CaCl_2或CaF_2能提高球团的还原速度。铬氧化物在MgO-Al_2O_3-SiO_2-CaO渣中与碳饱和铁液中溶解碳反应,其还原速度与渣中CrO活度的一次方成正比。还原速度的限制环节为CrO由渣中向渣-金界面的传递,在1600～1670℃,得传递系数数为10~(-5)～10~(-4)mol/min·cm~2。还原速度随熔渣的CaO/SiO_2比值提高及渣中GaF_2含量的增加而加快。
The reduction rate of chromium oxide in carbonaceous chrome ore pellets and slag was investigated by TG method and slag-gold interfacial reaction. The limiting part of the reduction speed of carbon-bearing chrome ore pellets is the carbon evolution reaction of CO on the chrome ore surface and the diffusion of carbon into the product layer through the product layer. Through the kinetic analysis and experimental results, the reduction speed and temperature, The relationship between granularity. The diffusion coefficient of carbon was found to be 10 ~ (-12) ~ 10 ~ (-11) cm ~ 2 / s at 1200 ~ 1300 ℃, and the rate constant of carbon evolution was 10 ~ (-7) ~ 10 ~ ) cm / s. The addition of CaCl 2 or CaF 2 to pellets can increase the reduction rate of the pellets. Chromium oxide reacts with carbon dissolved in carbon saturated molten iron in MgO-Al_2O_3-SiO_2-CaO slag, and its reduction rate is proportional to the first-order CrO activity in the slag. The limiting factor of the reduction rate is the transfer of CrO from the slag to the slag-gold interface, and the transfer coefficient is from 10 -5 to 10 -4 mol / min · cm -2 at 1600-1670 ° C. The reduction rate increases with the increase of slag CaO / SiO 2 ratio and the increase of GaF 2 content in slag.