RE_2O_3-MgO-SiO_2(RE=La,Nd,Sm,Gd和Y)熔体表面张力的计算模型(英文)

基于熔体组元离子半径和Butler方程,建立RE2O3-MgO-SiO2(RE=La,Nd,Sm,Gd和Y)熔体表面张力热力学计算模型。本模型利用纯组元的表面张力和摩尔体积以及熔体中各组元阳离子和阴离子半径可以获得E2O3-MgO-SiO2熔体表面张力随熔渣成分和温度的变化规律。计算1873 K La2O3-MgO-SiO2熔体等表面张力线并研究熔体成分对表面张力的影响。1873 K的纯组元La2O3,Gd2O3,Nd2O3和Y2O3的表面张力通过本模型计算分别为686、677、664和541 m N/m。除了Y2O3外,纯稀土氧化物的表面张力随其阳离子磁场强度增加而呈线性减小,而Y2O3的表面张力相对减小更多。表面张力的计算结果与文献数据一致,1873 K本模型平均偏差为1.05%。     

Linear analysis on the stability of lanthanide vapor complexes LnAl3Cli2(Ln = La to Lu)

The reactions LnCl3 (s) + (3/2)Al2Cl6 (g) = LnAl3Cl12 (g) for Ln = La to Lu were studied by quenching experi-ments in roughly the same temperature and pressure ranges (588-851 K and 0.01-0.22 MPa). Stability constants Kθ oflanthanide complexes LnAl3Cl12 were calculated from the measurements. The values of lg Kθ change linearly with theionpotential (Z+/r) of lanthanide(Ⅲ) from La to Gd and from Tb to Lu, respectively, indicating the Gd break. There exist in-clined W effect between lg Kθ and the total angular momentum L of lanthanide(Ⅲ). And hereby lanthanide elements aredivided into four segments, La-Nd, Pm-Gd, Tb-Ho, and Er-Lu. In each segment, the linearity is maintained.     

Short communication Linear analysis on the stability of lanthanide vapor complexes LnAl_3Cl_(12)(Ln=LatoLu)

The reactions LnCl3 (s) + (3/2)Al2Cl6, (g) = LnAl3Cl12 (g) for Ln = La to Lu were studied by quenching experiments in roughly the same temperature and pressure ranges (588-851 K and 0.01-0.22 MPa). Stability constants Kθ of lanthanide complexes LnAl3Cl12 were calculated from the measurements. The values of Ig Kθ change linearly with the ionpotential (Z+/r) of lanthanide(Ⅲ) from La to Gd and from Tb to Lu, respectively, indicating the Gd break. There exist inclined W effect between Ig Kθ and the total angular momentum L of lanthanide(Ⅲ). And hereby lanthanide elements are divided into four segments, La-Nd, Pm-Gd, Tb-Ho, and Er-Lu. In each segment, the linearity is maintained.     

A Safe and Brief Way for Preparing Anhydrous LnCl_3 (Ln=Sc, Y, La to Lu)

@李瑛 @王林山 @王育红     

Comparative study for mutual separation characteristics of binary mixed oxides Y2O3–Ln2O3 (Ln = Dy, Ho and Er) and Ho2O3–Er2O3 using stepwise chlorination–chemical vapor transport reaction mediated by vapor complexes KLnCl4

Mutual separation characteristics for binary oxide mixtures Y₂O₃–Dy₂O₃, Y₂O₃–Er₂O₃ and Ho₂O₃–Er₂O₃, in which these four kinds of rare earth ion(III) have very similar ion radius values, using a stepwise chlorination–chemical vapor transport (SC–CVT) reaction mediated by vapor complexes KLnCl₄ have been investigated in different temperature gradients. The unexpected results, together with that for Y₂O₃–Ho₂O₃ reported previously, are used to make a comparative analysis for the effect of ion radius values on the SC–CVT reaction for mutual separation of rare earths. Both the main deposition temperature region tendency and total transport amounts of chlorides for YCl₃ with respect to the ion radius of Y(III) were exceptional compared with those of LnCl₃ (Ln = Dy, Ho and Er), which were observed both in the degressive temperature gradient and the wave-type temperature gradient. The main deposition temperature of the chlorides produced from the oxide mixtures was in the order of DyCl₃ > YCl₃, HoCl₃ < YCl₃, ErCl₃ < YCl₃ and HoCl₃ > ErCl₃, total transported yields of the chlorides was in the order of DyCl₃ > YCl₃, HoCl₃ > YCl₃, ErCl₃ > YCl₃ and HoCl₃ > ErCl₃, and the largest separation factors 11.49 for Dy:Y, 15.28 for Ho:Y, 6.37 for Er:Y and 2.04 for Ho:Er in the lower temperature region were observed in the degressive temperature gradient, respectively. The results were discussed on the difference of ionic structure of Y on the one side and 4f lanthanoid elements of Dy, Ho and Er on the other hand, and verified that the ionic radius of the rare earth is one of the decisive factors of CVT reaction only for lanthanoid elements, not for Y. Furthermore, the improved separation factor values of 4.22 for Ho:Er and 3.20 for Er:Ho were obtained in the wave type temperature gradient due to variation of the dynamic conditions of CVT.