材料期刊网

总結了渣鉄間碳还原反应,包括FeO,MnO,CrO,V_2O_3的还原和铁液中脫硫。可以认为界面上化学反应很快达到平衡,而整个反应的控制步驟是对流扩散。发現反应級数,在熔体处于旋轉运动(用旋轉坩堝或旋轉攪拌棒)下为一級,处于仅由CO气泡攪动(用靜止坩堝)下为二級;处理脫硫和FeO的还原数据的結果表明,在上述两种情况下,扩散界面层厚度δ分别和轉速ω~(-1/2)和浓度C~(-1)成比例。 討論了固液界面上对流扩散原理在渣铁间碳还原反应中的应用,可以滿意地說明上述規律性。对于SiO_2的碳还原反应,根据現有实驗結果,尚不能肯定对流扩散的作用,可能此反应受界面化学反应所控制。

An investigation of the kinetics of the reactions between liquid slags and carbonsaturated iron including the reduction of FeO, MnO, CrO and V_2O_3 by carbon and the desulphurization of iron leads to the conclusion that the chemical reactions come to equilibrium rapidly at the slag-metal interface, while the controlling step is convective diffusion. It has been found that the reactions are of the first order when the melt is kept in a rotational motion, caused by the use of a rotating crucible or stirrer, and are of second order when the melt is kept in a stationary crucible and stirred by CO gas bubbles only. The thickness of the diffusion boundary layer δ, obtained from a treatment of Chipman's desulphurization data and Philbrook's data on the reduction of FeO, which correspond to the two fore-mentioned cases respectively, has been found to be inversely propertional to ω~(1/2), the square root of the angular velocity, and C_(FeO), the concentration of FeO in the slag phase.The present problem has been treated on the basis of the principle of convective diffusion across a solid-liquid interface according to Levich. It has been found that our findings can be satisfactorily explained by an application of this principle. An exceptional case is the reduction of SiO_2 from slags, which is probably controlled by interfacial chemical reaction.