用石墨为还原剂,将渣中La_2O_3还原人液态锡,以测定1500℃下La_2O_3—CaF_2和La_2O_3—CaF_2—CaO—SiO_2渣中La_2O_3的活度。对La_2O_3—CaF_2系,并用Gibbs—Duhem积分法求得CaF_2的活度。此外,在三个不同温度(1600,1550,1500℃)下,将固态La_2O_3用石墨还原人液态锡,以求得La在锡稀溶液中的活度系数。 根据液态渣的离子结构模型,对上述二渣系中La_2O_3的活度数据进行了简单的讨论。 Graphite as reductant, La 2 O 3 in slag was used to reduce liquid tin in order to measure the activity of La 2 O 3 -CaF 2 and La 2 O 3 -CaF 2 -CaO-SiO 2 slag at 1500 ℃. For La_2O_3-CaF_2, the activity of CaF_2 was calculated by Gibbs-Duhem integration method. In addition, the solid state La_2O_3 was reduced with liquid graphite at three different temperatures (1600, 1550 and 1500 ℃) to determine the activity coefficient of La in dilute tin solution. According to the ionic structure model of liquid slag, the activity data of La_2O_3 in the two slag systems are briefly discussed.