材料期刊网

利用石灰的加碳还原反应,设计了一个新的研究方法,以直接测定液态高炉型渣中CaO的活度.这一方法的成功,依靠溶剂金属的正确选择以降低熔液中钙的化学位,而使金属钙量提高到可以用化学分析测定的水平.我们估计钙在锡稀溶液中的活度系数很小,可能符合于我们的要求,因此研究了下列反应:CaO+C(石墨)=Ca(锡)+CO(气).以测定液态CaO-SiO_2和CaO-Al_2O_3-SiO_2渣中CaO的活度,在上式中符号下波纹线表示溶于渣中的组分,直线表示溶子金属中的组分,下同.对于CaO-Si0_2系,应用Gibbs-Duhem关系从CaO活度值算出了SiO_2的活度值,并根据一个统计力学模型讨论了活度曲线的形状.从CaO-Al_2O_3-SiO_2系的研究结果,可知在所研究的整个碱度范围內,渣中存在10%Al_2O_3都使CaO的活度增加;当Al_2O_3为20%时,则对CaO活度的影响视碱度不同而异.对Al_2O_3的这种行为,根据炉渣的离子结构理论提出了解释.

A new method,based on the carbothermic reduction of lime,has been devised forthe direct determination of the activity of lime in liquid blast-furnace-type slags.Thesuccess of the method depends upon the proper choice of the solvent metal to lower thechemical potential of calcium in the melt.Owing to the expected very small activity co-efficient of calcium in dilute solutions in tin,the reactionCaO(in slags)+C=Ca(in tin)+CO.has been studied with a view to evaluating activities of lime in liquid CaO-SiO_2 andCaO-Al_2O_3-SiO_2 slags.The activity values in the CaO-SiO_2 system have been used toderive silica activities through the Gibbs-Duhem relationship.The shape of the activitycurves is briefly discussed on the basis of a statistical mechanical model.It has been found from the results on the ternary system that the activity of lime isincreased by the presence of 10% alumina in the slags for the entire basicity range underinvestigation.An explanation based on the ionic constitution of slags is offered for thisbehaviour of alumina.