Verresr et Céramiques - Notes de cours

Les Verres 5 - La fabrication
5. La fabrication
5.1. Réactions chimiques
Na
Na
2
2
CO
SiO
5.2. Composition typiques
3
3
+ SiO
2
+ n SiO
1500 ° C
⎯⎯⎯⎯→
Na SiO
2
Na2SO4
⎯⎯⎯⎯→
+ CO
H. Schyns 5.1
2
( Na
2
3
O)(
SiO
2
)
↑
2 ( n+
1)
(en % en masse) de quelques verres industriels : d'après J. Zarzycki.
Verre SiO2 B2O3 Al2O3 Na2O K2O CaO MgO PbO
plat 72,5 1,5 13 0,3 9,3 3
bouteilles 73 1 15 10
"pyrex" 80,6 12,6 2,2 4,2 0,1 0,05
fibre 54,6 8,0 14,8 0,6 17,4 4,5
"cristal" 55,5 11 33
lampes 73 1 16 1 5 4
Take high quality sand, soda ash, limestone, saltcake and dolomite and melt at
white heat to a highly viscous consistency. Let the mixture digest for a time - and
you are well on the way to making one of the world's most important materials. This
is the basic composition of float glass, one of the greatest of all industrial process
inventions, comparable with Bessemer's innovations in steel manufacturing. In fact,
this is the formula for many types of mass-produced glass; except that float
demands highly exacting standards of quality, care and control unheard of in other
everyday uses of glass.
Material Glass Composition Reason for Adding
Sand 72.6 -
Soda Ash 13.0 Easier melting
Limestone 8.4 Durability
Dolomite 4.0 Working & weathering properties
Alumina 1.0 -
Others 1.0 -
At the heart of the world's glass industry is the float process - invented by Sir
Alastair Pilkington in 1952 - which manufactures clear, tinted and coated glass for
buildings, and clear and tinted glass for vehicles. The process, originally able to
make only 6mm thick glass, now makes it as thin as 0.4mm and as thick as 25mm.
Molten glass, at approximately 1000ºC, is poured continuously from a furnace onto
a shallow bath of molten tin. It floats on the tin, spreads out and forms a level