Effect of addition of surface active element on supersaturation in iron melt

在1873 K下，用Fe-Al合金和CaO-Al_2 O_3渣在Al_2O_3坩埚中进行了过饱和和平衡实验，研究了Te加入量和冷却速度对过饱和的影响。主要结论如下：1.在不含Te的平衡和过饱和实验中，对于给定的总铝含量，总氧含量不受冷却速率的影响.在添加Te的过饱和实验中，在[% Te]>0.005范围内，由于沉淀Al_2O_3的去除，总氧含量降低到一个恒定值，并且降低的程度随着冷却速率的降低而增加.考虑到Te对铁液/Al 2 O3界面能的影响，估算出临界过饱和比约为10^2.碲在Fe-Al合金和CaO-Al_2 O_3渣中的分配比与铝含量呈2/3的对数线性关系。用Fe_tO（<3mass%）对Fe-0.03- 0.44mass%Al合金和Fe-0.07- 0.58mass%Al-0.2- 0.6mass%Te合金进行了再氧化。研究了含CaO-Al_2 O_3渣系在1873 K下保温5 min和60 min时，渣系组成、Te加入量和初始Fe_tO含量对铝再氧化的影响。得出以下结论：1.在CaO-Al_2 O_3-Fe_tO渣系中，用Al_2O_3坩埚饱和5 min后，观察到以Al_2O_3、铁铝尖晶石和Fe_tO-Al_2 O_3混合物为主的酸不溶Al夹杂物.除CaO-Al_2 O_3-Fe_tO渣系在Al_2O_3坩埚中60 min时氧饱和，加入Te后，铁液中氧在快速冷却实验中均达到过饱和.除CaO-Al_2 O_3-Fe_tO渣在Al_2O_3坩埚中饱和5 min外，实验中Fe_tO与Al含量的关系处于平衡状态。

The supersaturation and equilibrium experiments were carried out at 1873K by using Fe-Al alloys and CaO-Al_2O_3 slags in an Al_2O_3 crucible, and the effects of Te addition and cooling rate on supersaturation were studied. The conclusions were summarized as follows.1. Total oxygen content for a given total aluminum content obtained in equilibrium and supersaturation experiments without Te was not influenced by the cooling rate.2. In supersaturation experiments with Te addition, total oxygen contents decreased to a constant value as a result of the removal of precipitated Al_2O_3 in the range of [% Te]>0.005 and the degree of lowering increased with a decrease in cooling rate.3. The critical supersaturation ratio was estimated to be about 10^2 by considering the effect of Te on the interfacial energy between liquid iron and alumina.4. Tellurium distribution ratio between an Fe-Al alloy and CaO-Al_2O_3 slag was found to be linearly related to the aluminum content in logarithmic form with a slope of 2/3, suggesting that Te in slag is present as divalent anion.An Fe-0.03-0.44mass% Al alloy or an Fe-0.07-0.58mass% Al-0.2-0.6mass% Te alloy was reoxidized with the Fe_tO(<3mass%)-containing CaO-Al_2O_3 slags at 1873 K for 5 and 60 min. The effects of slag compositions, Te addition and initial Fe_tO contents on the reoxidation of aluminum were studied. The following conclusions were obtained .1. Acid-insoluble Al as primary inclusions containing alumina, hercynite and Fe_tO-Al_2O_3 mixture was observed in the experiments of using CaO-Al_2O_3-Fe_tO slags saturated with an Al_2O_3 crucible at 5 min.2. The oxygen in liquid iron was supersaturated in the rapid cooling experments except those of the CaO-Al_2O_3-Fe_tO slags saturated with an Al_2O_3 crucible at 60 min with Te addition.3. The relations between Fe_tO and Al contents were observed to be in equilibrium in the experiments except those of the CaO-Al_2O_3-Fe_tO slags saturated with an Al_2O_3 crucible at 5 min.