Improvements in the Manufacture and Production of Water-glass, with Valuable Bye-products of the said Manufacture.
Year: 1896

page_text: Date of Application, 6th July, 1896
Complete Specification Left, 1st Apr., 1897-Accepted, 22nd May, 1897
TROVISIONAL OF MCIFICATION.
Improvements in the Manufacture and Production of Water-glass,
with Valuable Bye-products of the said Manufacture.
I, HEINRICH PROPFE, Ph.D. of Mannheim in the German Empire, Chemist, do
hereby declare the nature of this invention to be as follows:-
This process aims at being a rational, economical and rapid method of preparing
water-glass, with the simultaneous production of valuable bye-products.
It consists in intimately mixing silicic acid, with, or without, a reducing agent,
with the finely powdered alkali compound of the substance which it is desired to
obtain as a bye-product either alone, or in combination; the mixture is then submitted
to the action of sulphuric acid, and after removing the bye-product thus obtained, the
residue is treated with a reducing agent, and worked up for water glass.
The following examples indicate clearly the nature of my invention and the manner
in which it may be applied.
If it be desired to obtain hydrochloric acid along with water-glass, the method of
procedure is as follows:-(The parts are by weight).
100 parts of sand, 60 parts of rock-salt, and 4 parts of charcoal are finely ground
and intimately mixed, and then heated by means of waste gases in a muffle, or a
chamber built of stone, lying at the back of the melting furnace.
60 parts of 60 degrees sulphuric acid are. then led from a reservoir on to the
warm mixture; hydrochloric acid is immediately evolved at a comparatively low
temperature.
The action of sulphuric acid on the finely divided mixture is so vigorous, since.
the presence of silicic acid and wood charcoal appears to assist the action, that a
large proportion of the hydrochloric acid gas passes off without the application of
heat, which renders the condensation a simple matter. The acid is driven off at 200° C.
The hot, residual mixture is at once transferred to the melting furnace, and there fused
to water glass.
Instead of rock-salt, saturated brine solution may be used. The charcoal is then
replaced by saw-dust or peat, which is soaked with the brine, dried, mixed with sand,
and ground very fine. The mixture is then treated with sulphuric acid in the manner
already described.
The sulphuric acid may be also used in the form of bisulphate. It is mixed with
rock-salt in quantity depending on the amount of free acid it contains, and then
added to the charcoal and silicic acid, the latter in the form of sand, or sandstone.
The mass is then mixed and crushed. In order to drive off the hydrochloric acid, the
finely powdered mixture is then heated at 200° C., and fused to water-glass in the
melting-furnace.
It is also possible to obtain chlorine instead of hydrochloric acid as a bye-product.
For this purpose, rock-salt and salt-petre are added to the sand. On treating the
finely powdered mixture with sulphuric acid, there is produced a mixture of
hydrochloric and nitric acids, which may be worked up in the usual manner for
chlorine, whilst the residual mixture of silicic acid and sulphate is fused to water-glass
in the melting furnace, after the addition of charcoal.
If, in this process, rock-salt and charcoal, be dispensed with, and sulphuric acid be
allowed to act on a finely powdered mixture of 100 parts of sand and 85 parts of

page_text: saltpetre, nitric acid is evolved, and on removing this, the residue is mixed with charcoal,
and melted to water-glass.
Instead of nitric acid, derivatives of it (nitro-compounds) may be obtained as
bye-products. For this purpose the substance to be nitrated is added in the first
instance to the mixture of sand and saltpetre.
In order to obtain nitrobenzene, 76 parts of benzene are poured on the finely
powdered mixture of 100 parts of sand and 85 parts of saltpetre, the necessary
quantity of sulphuric acid being then slowly added."
The vigorous generation of heat which occurs in this process is considerably
moderated by the admixed silicious earth, which thus serves as a regulator. At the
end of the operation, which is hastened by agitation, the nitrobenzene floats on the
top. If any remains in the mixture, it is removed by pumping, or by steam, or by
draining, the mass being then treated with the reducing agent, and melted to water-
glass. Or, for example, in the case of naphthalene, 100 parts of sand, 85 parts of
saltpetre, and 128 parts of naphthalene are finely powdered, and slowly treated with
sulphuric acid, in order to maintain a temperature of 40-50°.
After the conversion of the saltpetre into sulphate the naphthalene has taken up all
the nitric acid, and on cooling forms a solid cake.
In preparing hydrochloric acid as a bye-product in this method, it is unnecessary
to employ pure sulphuric acid, if the production of hydrochloric acid alone be
desired. It is advantageous to make use of acid which has been previously applied
to the purification of mineral oil. The hydrocarbons intermixed with such an, acid
serve to replace the charcoal, or a portion of it, as reducing agent.
Although in the process described, the silicic acid takes no part in the first stage
of the reaction, it is important that the sand be mixed from the outset with the
material to be treated with sulphuric acid. Its presence facilitates the crushing of
the mass, and furthermore insures its closer and more uniform contact with the
sulphuric acid. It also conduces to maintaining an even temperature throughout the
mass, which is highly advantageous to the rapid progress of the reaction.
Duted this 6th day
1806
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture and Production of Water Glass
with Valuable Bye-products of the said Manufacture.
I, HEINRICH PROPFE, Ph.D. of Mannheim, in the German Empire, Chemist, do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement :-
This invention has for its object to provide a rational, economical, and rapid
method of preparing water glass, with the simultaneous production of valuable
bye-products.
It consists in intimately mixing silicic acid, with, or without, a reducing agent,
with the finely powdered alkali compound of the substance which it is desired to
obtain as a bye-product either alone, or in combination. The mixture is then
submitted to the action of sulphuric acid, and after removing the bye-product
thus obtained, the residue is treated with a reducing agent, and worked up for
water-glass.
The following examples indicate clearly the nature of my invention and the manner

page_text: in which it can be practically performed, but do not limit myself to the precise
details of these examples.
If it be desired to obtain hydrochloric acid along with water-glass, the method of
procedure is as follows (the parts are by weight) :-
100 parts of sand, 60 parts of rock-salt, and 4 parts of charcoal, are finely ground
and intimately mixed in a mill or otherwise, and the mixture is then heated which
may be done by means of waste gases in a muffle, or a chamber built of stone, lying
at the back of or otherwise in proximity to the melting furnace.
60 parts of 60 degrees sulphuric acid are then admitted to the warm mixture, which
can be conveniently done from a reservoir above; hydrochloric acid is immediately
evolved at a comparatively low temperature.
The action of sulphuric acid on the finely divided mixture is so vigorous, since the
presence of silicic acid and wood charcoal appears to assist the action, that a large
proportion of the hydrochloric acid gas passes off without the application of heat,
which renders the condensation a simple matter." The acid is driven off at
200° Centigrade. The hot, residual mixture is at once transferred to the. melting
furnace, and there. fused to water-glass.
Instead of rock-salt, saturated brine solution may be used. The charcoal is then
replaced by. saw-dust or peat, which is soaked with the brine, dried, mixed with sand,
and ground very fine. The mixture is then treated with sulphuric acid in the manner
hereinbefore described.
The sulphuric acid may be also applied in the form of bisulphate it being. mixed
with rock-salt in quantity depending on the amount of free acid it contains, and then
added to the charcoal and silicic acid, the latter in the form of sand, or sandstone.
The mass is then mixed, and crushed to a fine 'powder which 'may be done in a
mill. In order to drive off the hydrochloric acid, the finely powdered mixture is
then heated at 200° Centigrade and fused to water-glass in the melting furnace.
It is also possible to obtain chlorine instead of hydrochloric acid as a bye-product.
For this purpose, rock-salt and salt-petre are added to the sand or the like and the
whole finely powdered. On treating the finely powdered mixture with sulphuric
acid, there is produced a mixture of hydrochloric and nitric acids, which may be
worked up in the usual manner for chlorine, whilst the residual mixture of silicic
acid and sulphate after the addition thereto of charcoal is fused to water-glass in the
melting furnace.
If, in this process, rock-salt and charcoal be dispensed with, and sulphuric acid be
allowed to act on a finely powdered mixture of 100 parts of sand or the like, and
85 parts of saltpetre, nitric acid is evolved, and on removing this, the residue is mixed
with charcoal, and melted in the melting furnace to water-glass.
Instead of nitric acid, derivatives of it (nitro-compounds) may be obtained as bye-
products. For this purpose the substance to be nitrated is added in the first instance
to the mixture of sand or the like and saltpetre.
In order to obtain nitrobenzene, 76 parts of benzene are poured on the finely
powdered mixture of 100 parts of sand or the like and 85 parts of saltpetre, the
necessary quantity of sulphuric acid being then slowly added.
The vigorous generation of heat which occurs in this process is considerably
moderated by the admixed silicious earth, which thus serves as a regulator. At the
end of the operation, which is hastened by agitation, the nitrobenzene floats on the
top. If any remain in the mixture, it is removed by pumping, or by steam, or by
draining, the mass being then treated with the reducing agent, and melted in the
melting furnace to water-glass. Or, for example, in the case of naphthalene,
100 parts of sand or the like, 85 parts of saltpetre, and 128 parts of naphthalene are
finely powdered, and slowly treated with sulphuric acid, in order to maintain a
temperature of from 40° to 50° Centigrade.
After the conversion of the saltpetre into sulphate the naphthalene has taken up all
the nitric acid, and on cooling forms a solid cake.
In preparing hydrochloric acid as a bye-product in this method, it is unnecessary
to employ pure sulphuric acid, if the production of hydrochloric acid alone be

page_text: desired. It is advantageous to make use of acid which has been previously applied
"to the purification of mineral oil. The hydrocarbons intermixed with such an acid
serve to replace the charcoal; or a portion of it, as reducing agent.
Although in the process described, the silicic acid takes no part in the first stage of
-the reaction, it is important that the sand or the like be mixed from the outset with
the material to be treated with sulphuric acid as its presence facilitates the crushing
of the mass, and furthermore insures its closer and more uniform contact with the
sulphuric acid. It also conduces to maintaining an even temperature throughout
the mass, which is highly advantageous to the rapid progress of the reaction.
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 1
claim is :-
1. The manufacture or production of water-glass and the obtainment of valuable
bye-products, by treating with sulphuric acid, and in the presence of silicic acid, the
alkali compound of the substance to be obtained as a bye-product (either alone or in
combination) with or without a reducing agent, and after removal of the bye-product,
fusing the residue with a reducing agent in order to obtain water-glass.
2. In a process according to the preceding claiming clause wherein hydrochloric acid
is to be obtained as a bye-product, the employment of sulphuric acid which has previously
served in the purification of mineral oil, the impurities of the nature of hydrocarbons
which the said acid contains entirely or in part replacing the reducing agent which
would otherwise be employed in the process.
Dated this 1st day of April 1897.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.