CERTAIN IMPROVE- MENTS IN THE MANUFACTURE OF CARBONATE OF SODA
Year: 1837

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, FRANCIS
GYBBON SPILSBURY, of Newport Street, Oxford Street, in the County Mid-
dlesex, Engineer, and WILLIAM MAUGHAM, of Newport Street, Lambeth, in
the County of Surry, Chemist, send greeting.
WHEREAS His late most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Eleventh day of January, in the seventh year of His reign,
did, for Himself, His heirs and successors, give and grant unto us, the said
Francis Gybbon Spilsbury and William Maugham, His especial license, full
power, sole privilege and authority, that we, the said Francis Gybbon Spils-
bury and William Maugham, our exors, adññors, and assigns, or such others
as we, the said Francis Gybbon Spilsbury and William Maugham, our exors,
admors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, our Invention of "CERTAIN IMPROVE-
MENTS IN THE MANUFACTURE OF CARBONATE OF SODA;" in which said Letters
Patent is contained a proviso that we, the said Francis Gybbon Spilsbury and
William Maugham, or one of us, shall cause a particular description of the
nature of our said Invention, and in what manner the same is to be performed,
to be inrolled in His said Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
Francis Gybbon Spilsbury and William Maugham, do hereby declare the
nature of our said Invention, and the manner in which the same is to be
performed, are fully described and ascertained in and by the following state-
ment thereof, reference being had to the Drawings hereunto annexed, and to
the figures and letters marked thereon; that is to say :-
Our Invention relates, -
First, to a method of condensing the muriatic acid gas which is now
suffered to escape into the atmosphere with the smoke and vapour of the
furnaces.
Secondly, to a method of obtaining carbonate of soda from muriate of
soda without first producing a sulphate of soda, whereby the expensive
and laborious processes of obtaining and decomposing that sulphate are
avoided.
It is well known that in order to condense the muriatic acid gas (which
escapes so largely in that part of the process of making carbonate of soda
which consists in converting muriate of soda to sulphate of soda), it is only
necessary to bring the smoke and vapours which issue from the reverberatory
furnaces, in converting muriate of soda into sulphate of soda, into contact with
a sufficient body of water; but the smoke cannot be so treated without at
the same time being cooled down, whereby the draft to the furnace is pro-
portionably diminished. A high temperature is so necessary to the rapid and
effectual decomposition of muriate of soda by sulphuric acid, that manufac-
turers prefer occasionally paying damages for the nuisance they occasion to the
neighbourhood rather than to submit to the positive and daily loss which
must be the consequence of any check to the draught of their decomposing
furnaces. It is therefore desirable to render the draught of the furnace
independant of the higher or lower temperature of the column of air contained
in the chimney, a mode of accomplishing which constitutes the first part of
our Invention.

page_text: transversely. In this partition are firmly embedded three pipes F, F, F, not
exceeding four inches diameter, and about eighteen inches long, open at both
ends. These pipes form the only communication whereby the smoke can
páss from the part of the flue A to that marked E. The jets of the steam
pipes C, C, C, are inserted, as shewn, into the centre of the parallel and
opposite open pipes F, F, F. They enter about two inches, the smoke
passing around them freely in its passage through F, F, F, in the direction
of the arrows. The effect of this arrangement is, that so soon as the steam
of from ten to fifteen pounds on the inch is permitted to rush out of the
jets C, C, C, it communicates so great a velocity to the columns of air
contained in the open pipes F, F, F, that a most powerful draught is created
in the flue A, E, independent of any aid from the natural draught of the
chimney. Although only three steam jets and air pipes are shewn in the
Drawing, their numbers must be increased as the number of furnaces to be
worked increases. The arrangement here described is sufficient for two large
decomposing furnaces such as are ordinarily employed. Without exactly
determining the number, which must depend upon circumstances peculiar to
each manufactory, it may be generally stated as a rule that five air pipes of
four inch diameter, and five steam jets of one quarter of an inch aperture.
projecting steam of from ten to fifteen pounds pressure, will be found sufficient
to work four large reverberatory furnaces more effectually than a chin:ney
two hundred and fifty feet high. The end of the flue E is made to communi-
cate with any form of condenser the manufacturer may choose, whereby the
vapour and gas traversing the flue may be brought into contact with a body of
water sufficient to condense the aqueous vapour and absorb the acid; but as
such condensation and means for effecting the same are well known, and as
we do not claim any particular form, it is unnecessary to enter into a descrip-
tion thereof. After the smoke has been thus made to pass over the water,
the uncondensable gases are to be carried into a chimney to escape in the
ordinary way.
We will now describe our second improvement, which consists in a mode of
producing carbonate of soda by converting muriate of soda into a fluoride of
sodium or fluosilicate of soda (the latter is to be preferred as being the more
insoluble), instead of first obtaining a sulphate, as ordinarily performed in
manufacturing carbonate of soda. For this purpose concentrated fluoric acid,
obtained from Derbyshire spar in any of the usual methods, and as is well
known, is to be mixed with its weight of muriate of soda, and so much water
added as will prevent the muriatic acid from going off in the state of gas.
There is then to be added sufficient ground flint or other silicious matter to

page_text: convert the fluoride of sodium into fluosilicate of soda. The supernatant
liquor, consisting of concentrated muriatic acid holding a little fluosilicate of
soda in solution, is then to be drained off. The remaining fluosilicate is then
to be washed slightly with as little water as possible, after which it is to be
transferred to a furnace and subjected to a low red heat to drive off any
adhering muriatic acid. The dry product is next to be mixed with double its
weight of powdered chalk or limestone, and the whole boiled in water for
several hours. The effect of this operation is a double decomposition, whereby
the fluosilicate of soda and carbonate of lime are converted into fluosilicate of
lime and carbonate and sesquicarbonate of soda, the latter being dissolved in
the water.
This supernatant liquor is to be drawn off, the residuum well
washed, and the washings added to the first liquor; the whole is then to be
evaporated to dryness, and the resulting product heated to redness. What
remains is pure carbonate of soda, which may be redissolved in water and
chrystallized in the ordinary way. If, instead of the fluosilicate of soda, the
fluoride of sodium is preferred, then the same process is to be gone through,
with the omission of the ground flints, and the result will be fluoride of
calcium and carbonate of soda..
Having thus described our Invention, and the best means we are
acquainted with for carrying the same into effect, we would remark, in
the first place, as respects the condensation of the muriatic acid gas, we do
not claim any form of condenser or any peculiar method of bringing the
gas and smoke from the decomposing furnaces into contact with water,
neither do we confine ourselves to the exact arrangements herein described.
But we claim as the first part of our Invention, the application of a jet or
jets of steam playing into the flue or flues of the ordinary decomposing
furnaces employed by alkali makers for the purpose of impelling the column
of vapour and gases contained within them independent of or in conjunction
with the ordinary draught of the chimney when performing that part of the
process of making carbonate of soda, which consists in converting muriate of
soda into sulphate of soda.
Secondly, we claim the treating of muriate of soda with fluosilicic acid in
the manufacture of carbonate of soda, in place of converting muriate of soda
into sulphate of soda, and then into carbonate of soda, as heretofore practised.
In witness whereof, we, the said Francis Gybbon Spilsbury and William
Maugham, have hereunto set our hands and seals, this Eleventh day
of July, in the year of our Lord One thousand eight hundred and
thirty-seven..
(L.B.) W. MAUGHAM.

page_text: AND BE IT REMEMBERED, that on the Eleventh day of July, in the
year of our Lord 1837, the aforesaid William Maugham came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Inrolled the Eleventh day of July, in the year of our Lord One thousand
eight hundred and thirty-seven.