Melt Synthesis, Structural, Characterization and Scaling of Swelling 2:1-Layer Silicate Materials
type: CreativeWork
description: Melt synthesis, characterization, and refinement of single crystal structures of swelling 2:1-layer silicates were the main fundamental topics of the presented thesis. In particular, large scale syntheses of both lithium and sodium fluorohectorite were successfully achieved. Furthermore, the crystal structure of one-, and two-layer hydrate of sodium fluorohectorite and the one-layer hydrate of sodium brittle mica were thoroughly investigated and characterized in detail. Swelling sodium fluorohectorite with good crystallinity in an ideal composition of Na0.85[Mg2.15Li0.85]Si4O10F2 was synthesized for investigating the hydrated structure. Melt synthesis was done in closed molybdenum crucibles using pure reagents (glass with composition Na2O-2SiO2, Li2SiO3 MgF2, MgO, SiO2). The crystal structures of one- and two-layer hydrate of sodium fluorohectorite were studied. The one-layer hydrate of sodium fluorohectorite (at relative humidity 45 %) showed two planes of interlayer sodium along [100]. The two-layer hydrate of sodium fluorohectorite showed sodium interlayer cations being located in the middle of the interlayer. In addition, sodium brittle mica with a target composition Na4[Mg6]Si4Al4O20F4 was successfully synthesized via melt synthesis in a gas tight molybdenum crucible and the refinement of the one-layer hydrate of sodium brittle mica was done. The synthetic sodium brittle mica swells only to the one-layer hydrate and could not be further hydrated to the two-layer hydrate. Generally, natural swelling layer silicates (smectites) usually contain impurities such as iron oxide (pigmentation material), quartz, and carbonate. However, these impurities hinder the employment of swelling layer silicates in industry for cutting edge and advanced applications. In addition, they suffer from small particle size under 5 µm limiting their aspect ratio. For industrial applications, pure synthetic swelling layer silicates with superior properties are highly desirable. Therefore, …
abstract: Melt synthesis, characterization, and refinement of single crystal structures of swelling 2:1-layer silicates were the main fundamental topics of the presented thesis. In particular, large scale syntheses of both lithium and sodium fluorohectorite were successfully achieved. Furthermore, the crystal structure of one-, and two-layer hydrate of sodium fluorohectorite and the one-layer hydrate of sodium brittle mica were thoroughly investigated and characterized in detail. Swelling sodium fluorohectorite with good crystallinity in an ideal composition of Na0.85[Mg2.15Li0.85]Si4O10F2 was synthesized for investigating the hydrated structure. Melt synthesis was done in closed molybdenum crucibles using pure reagents (glass with composition Na2O-2SiO2, Li2SiO3 MgF2, MgO, SiO2). The crystal structures of one- and two-layer hydrate of sodium fluorohectorite were studied. The one-layer hydrate of sodium fluorohectorite (at relative humidity 45 %) showed two planes of interlayer sodium along [100]. The two-layer hydrate of sodium fluorohectorite showed sodium interlayer cations being located in the middle of the interlayer. In addition, sodium brittle mica with a target composition Na4[Mg6]Si4Al4O20F4 was successfully synthesized via melt synthesis in a gas tight molybdenum crucible and the refinement of the one-layer hydrate of sodium brittle mica was done. The synthetic sodium brittle mica swells only to the one-layer hydrate and could not be further hydrated to the two-layer hydrate. Generally, natural swelling layer silicates (smectites) usually contain impurities such as iron oxide (pigmentation material), quartz, and carbonate. However, these impurities hinder the employment of swelling layer silicates in industry for cutting edge and advanced applications. In addition, they suffer from small particle size under 5 µm limiting their aspect ratio. For industrial applications, pure synthetic swelling layer silicates with superior properties are highly desirable. Therefore, …
author: Kalo, Hussein
date published: 2012-09-08
date modified: 2026-07-27T18:49:06Z
provider: Universität Bayreuth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universität Bayreuth