The influence of bulk composition on the diffusivity of carbon dioxide in Na aluminosilicate melts
The influence of bulk composition on the diffusivity of carbon dioxide in Na aluminosilicate melts
复制标题
本体成分对硅铝酸钠熔体中二氧化碳扩散率的影响
DOI：
10.2138/am-2002-11-1221
复制
发表时间：
2002
影响因子：
3.1
通讯作者：
H. Keppler
中科院分区：
文献类型：
--
作者：
M. Sierralta;M. Nowak;H. Keppler
摘要 使用扩散偶技术在 1523 K 和 0.5 GPa 下研究了 NaAlSi3O8 + nNa2O (n = 0- 6.87 wt%) 和 NaAlSi3O8 + nH2O (n = 0-2 wt%) 熔体中溶解二氧化碳（CO2 和 CO32-）的体积扩散率。起始玻璃对的 CO2 含量在 0 至 0.2 wt% 之间变化。通过红外光谱测定大量 CO2 的对称浓度-距离分布。将误差函数拟合到曲线上以获得大量二氧化碳的表观化学扩散系数。在研究的成分范围内，大量 CO2 的扩散率随 Na2O 和 H2O 含量呈指数增加，因此随非桥接氧原子/四面体阳离子的比率 (NBO/T) 呈指数增加。本体 CO2 扩散率从 NaAlSi3O8 熔体中的 logDCO2 = -11.38（DCO2，单位为 m2/s）增加到含有 6.87 wt% Na2O 过量的 NaAlSi3O8 熔体中的 logDCO2 = -10.92，以及含有 2 wt% H2O 的 NaAlSi3O8 熔体中的 logDCO2 = -10.91。这些数据意味着：(1) CO2 物质（分子 CO2 和 CO32-）的扩散率非常相似，或者 (2) 淬火玻璃中 CO2 的形态与熔体中的形态非常不同。
Abstract The bulk diffusivity of dissolved carbon dioxide (CO2 and CO32-) in NaAlSi3O8 + nNa2O (n = 0- 6.87 wt%) and in NaAlSi3O8 + nH2O (n = 0-2 wt%) melts was investigated at 1523 K and 0.5 GPa using the diffusion couple technique. CO2 contents of the starting glass pairs varied between 0 and 0.2 wt%. Symmetrical concentration-distance profiles of bulk CO2 were determined by infrared spectroscopy. An error function was fitted to the profiles to obtain apparent chemical diffusion coefficients of bulk CO2. In the investigated compositional range, the diffusivity of bulk CO2 increases exponentially with Na2O and H2O content and thus exponentially with the ratio of nonbridging oxygen atoms per tetrahedral cations (NBO/ T). The bulk CO2 diffusivity increases from logDCO₂ = -11.38 (DCO₂ in m2/s) in NaAlSi3O8 melt to logDCO₂ = -10.92 in NaAlSi3O8 melts containing 6.87 wt% Na2O excess, and to logDCO₂ = -10.91 in NaAlSi3O8 melts containing 2 wt% H2O. These data imply that either: (1) the diffusivities of the CO2 species (molecular CO2 and CO32-) are very similar, or (2) the speciation of CO2 in the quenched glasses is very different from the speciation in the melt.