Process for Producing Opalescent Glass from a Glass Mixture containing Silicofluorides of Alkalis or Compounds thereof.
Year: 1890

page_text: Date of Application, 18th Feb., 1890
Complete Specification Left, 31st Oct., 1890-Accepted, 13th Dec., 1890
PROVISIONAL DIMIT
Process for Producing Opalescent Glass from a Glass Mixture
containing Silicofluorides of Alkalis or Compounds thereof.
1, CHARLES HUELSER of the firm of Huelser & Co. of 142 Fleet Street in the
City of London, Solicitors of Patents, do hereby declare the nature of this invention,
a communication to me from abroad by Joseph Kempner of Berliner Strasse No. 60
Goerlitz in the Empire of Germany Merchant, to be as follows:-
The object of this invention is a new process, derived from melting experiments,
for producing opalescent glass. Said experiments have demonstrated that fluorides of
alkalis alone do not produce opalescent glass,-which fact is also established by other tests
(vide Dingler's Polytechnisches Journal, Vol. 256 p. 361, 1885)-that even cryolite pro-
duces opalescent glass only if added in a large proportion, that however silicofluorides
of alkalis (silicofluoride of sodium or silicofluoride of potassium) or compounds
thereof, when added in a relatively small quantity to a glass batch of any suitable
composition, produce an intensely opalescent glass. The communicator, for instance,
ascertained, that when adding to three equal batches of the same composition
respectively ten grammes of fluoride of sodium, cryolite and silicofluoride of sodium,
the first two mixtures resulted in a perfectly clear white glass, but the third mixture,
containing silicofluoride of sodium, in a completely milky opalescent glass.
When making batches for opalescent glass in glass works, the proportion of silico-
fluoride of alkali to be incorporated will naturally depend on the nature of the sub-
stances constituting the glass batch, on the temperature of the furnace and on the
degree of dullness desired to be produced.
If, for instance, in an ordinary cryolite opalescent glass batch consisting of 30
(thirty) units of cryolite, 46 (forty six) units of carbonate of soda 12 (twelve) units
of chalk and 165 (one hundred and sixty five) units of sand, the cryolite is replaced
by 25 (twenty five) units of silicofluoride of sodium, and eventually 20. (twenty)
units of kaolin, a glass perfectly equal to cryolite opalescent glass is obtained; the
kaolin however is not absolutely necessary but any other aluminiferous mineral may
be substituted therefor, as it merely serves to produce a glass similar to cryolite.
Silicofluorides of alkalis may also be advantageously employed for enriching any
opalescent glass batches. In the batch above referred to, for instance 15 (fifteen)
units of the cryolite contained therein may be replaced by silicofluoride of alkalis.
The batch which would then be composed of 15 (fifteen) units of cryolite, 46 (forty
six) units of carbonate of soda, 12 (twelve) units of chalk, 165 (one hundred and
sixty five) units of sand and 12 (twelve and a half) units of silicofluoride of sodium
results in an opalescent glass which is at least as good as if only cryolite had been
employed.
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COMPLETE SPECIFICATION.
Process for Producing Opalescent Glass from a Glass Mixture
containing Silicofluorides of Alkalis or Compounds thereof.
1, CHARLES HUELSER of the firm of Huelser & Co. of Temple Chambers London,.
International Patent Agency, do hereby declare the nature of this invention, a com-
munication to me from abroad by Joseph Kempner of Berlinerstrasse No. 60,
Goerlitz, in the Empire of Germany, Manufacturer, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the following
statement :-
This invention relates to the manufacture of opalescent glass and has for its purpose

page_text: to produce such glass with the application of silicofluorides of alkalis. My melting
experiments from which I have derived the improved process have demonstrated that
fluorides of alkalis alone do not produce opalescent glass, which fact is also
established by other tests (vide Dingler's Polytechnisches Journal, Vol. 256 p. 361,
1885) that even cryolite produces opalescent glass only if added in a large pro-
portion, that however silicofluorides of alkalis (silicofluoride of sodium or silicofluoride
of potassium) or compounds thereof, when added in a relatively small quantity to a
glass batch of any suitable composition, produce an intensely opalescent glass. The
communicator, for instance, ascertained that when adding to three equal batches of
the same composition respectively 10 grammes of fluoride of sodium, cryolite and
silicofluoride of sodium, the first two mixtures resulted in a perfectly clear white
glass, but the third mixture, containing silicofluoride of sodium, in a completely milky
opalescent glass. When making batches for opalescent glass in glass works, the pro-
portion of silicofluoride of alkali to be incorporated will naturally depend on the
nature of the substances constituting the glass batch, on the temperature of the
furnace and on the degree of dulness desired to be produced. If, for instance, in an
ordinary cryolite opalescent glass batch consisting of 30 units of cryolite, 46 units
of carbonate of soda, 12 units of chalk and 165 units of sand, the cryolite is replaced
by 25 units of silicofluoride of sodium, and eventually 20 units of kaolin, a glass
perfectly equal to cryolite opalescent glass is obtained; the kaolin however is not
absolutely necessary but any other aluminiferous mineral may be substituted
therefor, as it merely serves to produce a glass similar to cryolite.
Silicofluorides of alkalis may also be advantageously employed for enriching any
opalescent glass batches. In the batch above referred to, for instance, 15 units of the
cryolite contained therein may be replaced by silicofluoride of alkali. The batch
which would then be composed of 15 units of cryolite, 46 units of carbonate of soda,
12 units of chalk, 165 units of sand and 124 units of silicofluoride of sodium results
in an opalescent glass which is at least as good as if only cryolite had been
employed.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :
A process for producing opalescent glass embodying the application of silicofluorides
of alkalis or compounds thereof, the whole substantially as set forth.
Dated this 31st day of October 1890.
HUELSER & Co.,
Agents for Applicant.