Silicate Glasses and Melts

Bjorn Mysen,Pascal Richet

• Publisher: Elsevier Science
• Year: 2018
• ISBN:
  9780444637093
• Edition: 2
• Topic: Physical Sciences
• Subtopic: Geology & Earth Sciences

Silicate Glasses and Melts, Second Edition describes the structure-property-composition relationships for silicate glasses and melts from a geological and industrial perspective. Updated sections include (i) characterization of silicate melt and COHN fluid structure (with and without dissolved silicate components) with pressure, temperature, and redox conditions and responses of structural variables to chemical composition, (ii) determination of solubility and solution mechanisms of COHN volatiles in silicate melts and minerals and of solubility and solution mechanisms of silicate components in COHN fluids, and (iii) effects of very high pressure on structure and properties of melts and glasses.

This new book is an essential resource for researchers in a number of fields, including geology, geophysics, geoscience, volcanology, material science, glass science, petrology and mineralogy.

• Brings together multidisciplinary research scattered across the scientific literature into one reference, with a focus on silicate melts and their application to natural systems
• Emphasizes linking melt properties to melt structure
• Includes a discussion of the pros and cons of the use of glass as a proxy for melt structure and properties
• Written by highly regarded experts in the field who, among other honors, were the 2006 recipients of the prestigious G.W. Morey award of the American Ceramic Society

Chapter 1

The Discovery of Silicate Melts: An Applied and Geological Perspective

Abstract

Since glass was invented, it has found new uses whenever improvements have been made either in manufacturing processes or in properties of the final product. The present differs from the past in the degree of sophistication required to understand better the composition-property relationships that allow glass to meet the competition that originates from other kinds of materials and, especially, to meet the ambitious goal of tailoring glasses or melts for specific applications.

In the earth sciences, the relevant ranges of pressure, temperature, and chemical compositions are wider still than in industry. Experimental studies are much simpler and more restricted than processes that have actually taken place on the earth since (and during) its formation. Hence modeling must be introduced to interpolate or extrapolate the necessary limited number of experimental data to real processes. As stated by Lord Kelvin (Thomson, 1871), “The essence of science, as is well illustrated by astronomy and cosmical physics, consists in inferring antecedent conditions, and anticipating future evolutions, from phenomena which have actually come under observation.”

A key step in this effort is the understanding of the relationships between composition, structure, and physical properties of silicate glasses and melts. Such relationships are fairly simple for a property like melt density at room pressure, so empirical modeling can be adequate. For viscosity, in contrast, the complex composition and temperature dependencies need a great deal of fundamental information to be understood quantitatively. The purpose of this book is to review the current state of the art in such matters.

Keywords

Silicate melts; Glass forming; Glass composition; Plutonism; Glass science; Igneous petrology

Outline

• 1.1 Introductory Comments
• 1.2 The Early History of Glass
  • 1.2.1 The Beginnings of an Art
  • 1.2.2 An Industrial Revolution
• 1.3 Glass and Science
  • 1.3.1 A Scientific Material
  • 1.3.2 Descartes and the Foundation of a Science
  • 1.3.3 The Effects of Composition
• 1.4 The Discovery of Natural Melts
  • 1.4.1 The Origin of Neptunism
  • 1.4.2 From Extinct Volcanoes to Magma
• 1.5 The Physical Chemistry of Melts
  • 1.5.1 The Measurements of Physical Properties
  • 1.5.2 Toward the Glass Transition
  • 1.5.3 The First Glimpses of Structure
  • 1.5.4 The Search for New Compositions
  • 1.5.5 A Geological Outlook
• References
• Further Reading

1.1 Introductory Comments

Under a thin sedimentary layer, the rocks that make up the continents and the ocean floor were formed by cooling of magma. The name igneous rocks (ignis, fire in Latin) is a reminder of this origin. Today, such a magmatic source is taken for granted, although such an origin was established only about two centuries ago. In fact, since the beginnings of glass four millennia ago to the end of the 18th century, molten silicates were of concern solely to glass makers and subsequently to metallurgists. Hence, it is hardly a novelty that the properties of silicate melts are as important in materials sciences as in the earth sciences.

1.2 The Early History of Glass

1.2.1 The Beginnings of an Art

Glass is one of the earliest man-made materials (e.g., Bimson and Freestone, 1987; Tait, 1991; Shortland and Degryse, 2018). It appeared more than 4000 years ago in the Middle East, about five millennia after other oxide-based materials (ceramics, plaster, and lime), but it closely followed the first metals, copper and lead, and even preceded iron.

It is not known whether glass was first produced in Mesopotamia, Egypt, or Syria, and whether it was made during ceramic or metallurgical operations. In fact, a single origin is unlikely. Similar sequences of discoveries probably led to similar processes and products in different places in the Middle East. Their common feature was to be small, imperfect pieces that might have originally been accidental by-products of glazing applied to stone and faience before repeated efforts allowed bulk glass to be produced, mainly as beads.

What may actually be termed glassmaking apparently dates back to the 16th century BC, as real glass pieces appear in the archeological record in the Late Bronze age. These early glasses have familiar compositions (Table 1.1). They are not translucent but opaque and vividly colored by various metals such as copper (red and blue-red), iron (black, brown, and green), antimony (yellow), cobalt (blue), or tin (white) (Oppenheim et al., 1970). The substances that yielded these various colors were thus already identified empirically at these early stages. In Egypt, it is not fortuitous that glassmakers were called “makers of lapis lazuli.” As a matter of fact, this was the first time that a given property of a material—its color—could be varied almost at will. Unknowingly, glassmakers had thus discovered the rich possibilities offered by continuous solid solutions, and they also observed that small changes in ingredients (i.e., in chemical composition) could result in marked changes in a physical property.

Table 1.1

Composition of Some Ancient Glasses (wt%)^a

	SiO2	Na2O	Al2O3	K2O	CaO	MgO	Fe2O3	PbO
Babyloni...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• Chapter 1: The Discovery of Silicate Melts: An Applied and Geological Perspective
• Chapter 2: Glass Versus Melt
• Chapter 3: Glasses and Melts Versus Crystals
• Chapter 4: Structure and Property Concepts
• Chapter 5: Silica
• Chapter 6: Properties of Metal Oxide-Silica Systems
• Chapter 7: Structure of Metal Oxide-Silica Systems
• Chapter 8: Properties of Aluminosilicate Systems
• Chapter 9: Structure of Aluminosilicate Glass and Melt
• Chapter 10: Properties of Iron-Silicate Glasses and Melts
• Chapter 11: Structure of Iron Silicate Glasses and Melts
• Chapter 12: Titanium-Bearing Systems
• Chapter 13: Phosphorus in Silicate Systems
• Chapter 14: Properties of Hydrous Melt and Glass
• Chapter 15: Water Solution Mechanisms and Structure
• Chapter 16: Reactive Silicate-C-O-H-N-S Systems
• Chapter 17: Noble Gases, Molecular Species, Hydrogen, and Halogens
• Chapter 18: Chemically Complex Melts and Natural Magma
• Index