Reinvestigation of pure Na-nepheline like compounds obtained from the thermal conversion of zeolite LTA

被引：3

作者：

Vulic, Predrag ^{[1
,2
]}

Kahlenberg, Volker ^{[1
]}

Gspan, Christian ^{[3
]}

Dimitrijevic, Radovan ^{[2
]}

机构：

[1] Univ Innsbruck, Inst Mineral & Petrog, A-6020 Innsbruck, Austria

[2] Univ Belgrade, Fac Min & Geol, Crystallog Lab, Belgrade 11000, Serbia

[3] Graz Univ Technol, Ctr Electron Microscopy Graz, Inst Electron Microscopy & Fine Struct Res, A-8010 Graz, Austria

来源：

EUROPEAN JOURNAL OF MINERALOGY | 2013年 / 25卷 / 03期

基金：

瑞士国家科学基金会;

关键词：

Na-nepheline (synthetic); monoclinic trinepheline; TEM; Rietveld refinement; SUB-POTASSIC NEPHELINES; TRINEPHELINE;

D O I：

10.1127/0935-1221/2013/0025-2293

中图分类号：

P57 [矿物学];

学科分类号：

070901 ;

摘要：

A polycrystalline sample synthesized through the thermal transformation of zeolite Na-LTA and originally described as standard nepheline was re-investigated. Transmission electron microscopy (TEM) proved the presence of a structure with a tripled c unit-cell parameter compared to that observed in classical nepheline. Consequently, the theoretical X-ray powder diagrams of all known trinepheline compounds were compared with the experimental powder pattern, leading to the conclusion that the material is actually a mixture of two phases. Rietveld refinement against XRPD data using structural models of (a) classical Na-nepheline (S. G. P6(3), a = 9.971(3), c = 8.349(2) angstrom) and (b) monoclinic trinepheline (space group P112(1), a = 9.995(4), b = 9.963(4), c = 24.988(7) angstrom, gamma = 119.75(3)degrees) resulted in a satisfying agreement between calculated and observed step intensities (chi(2) = 1.96, R-wp = 11.3, R-p = 8.77). The additional quantitative analyses of the samples obtained in a temperature range of stability of nepheline (900-1100 degrees C) showed the presence of both structures, and also a gradual increase of the weight fraction of the monoclinic trinepheline phase with increasing temperature.

引用

页码：473 / 478

页数：6