Page 54 - Glass-Technology International no. 3-2019

CHEMICAL TEMPERING

pering in sectors such as
construction, for example.

Gianfranco Rivaroli, RIVA:
Another aspect that we
need to make clear regards
costs. Chemical tempering
is not, as is often consid-
ered, more expensive, on
the contrary. It all depends
on how many glass sheets
you are tempering with the
plant. A chemical temper-
ing plant usually consumes
about 15 per cent of the
energy installed. The lim-
its of a chemical plant are
those regarding time and,
therefore, production yield.

Glass-Technology Interna-
tional (GTI): What about
large-sized glass sheets –
do they take a longer time
to be tempered? And what
about glass thickness?
Gianfranco Rivaroli, RIVA:
Tempering time depends
only on the size of the plant
installed, and it is the same
for the glass case of a watch
to a large, 3-metre glass
pane for a luxury yacht.

Alessandro Rivaroli RIVA: It
all depends on the chemi-
cal reaction time … We
are speaking about the
time needed for the ions to
penetrate the glass. There
are, however, special glass
types, such as those used
for smartphones and touch
devices, that can be tem-
pered chemically in about
3 - 4 hours, compared to
the 16 hours for chemical
tempering of float glass.
Over the past ten years or
even a lot more, we have

52 Glass-Technology International 3/2019