铝硅酸盐熔体微结构单元的探讨

Discussion on the microstructure units of alumino-silicate melts

本文是一篇综述,讨论在熔融铝硅酸盐和铅酸盐中Al的两性行为。这是冶金学和岩石学中一个至今尚无可靠结论的问题。作者认为:每个四配位的Al_a都含一个配位键,例如Al-O Ca Si或Al-O Ca Al。相应的非桥氧O_nb并没有消失,而是变成了三价氧离子。碱性Al_b能否出现取决于该体系的酸碱平衡。构筑硅酸盐的键合结构模型时,作者建议用5种Si-O四面体(Q_n)作为微结构单元。即,用它们的相对量和微观化学位描述其宏观物性(如组元活度)。为了沟通铝硅酸盐的微观结构与宏观物性,仍可用5种Q_n作为微结构单元。其中所含Al_a的影响用各种Q_n微观化学位的相应变化来反映。对于铝酸盐,建议用Al_a-O四面体(T_n)作为微结构单元。

This is a review concerning the discussion on amphoterie behavior of Al in molten alumino-silicates and aluminates, which is significant in both metallurgy and petrology. So far it does not acquire a reliable conclusion. According to the present authors every one 4-coordinated Al-a gains a coordination bond, such as Al-O(-Si)(-Ca)or Al-O--Al(-Ca). Meanwhile, the corresponding non-bridging oxygen O-nb does not disappear, it becomes a O3-. Whether the 6-coordinated Al-b can appear or not is determined by the acid-basicity equilibrium of the system. For the cluster model of silicates it was suggested by the present authors that 5 Si-O tetrahedra (Q(n)) should be used as the microstructural units. Namely, to describe the macro-properties (as component activity) based on the information of the molar fraction and micro chemical potential of these Q(n). In order to link the microstructure with the macro-properties of alumino-silicates 5 kinds of Q(n) still can be used. The influence of containing Al may be reflected by the associating change of the micro-chemical potential of these Q(n). For aluminates, it is suggested to use Al-n-O tetrahedral (T-n) as the microstructural units.