AN IMPROVEMENT OR IMPROVEMENTS IN THE PROCESS OR PROCESSES OF MANUFACTURER THE CARBONATE OF SODA
Year: 1840

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Jonn
WILSON, of Liverpool, in the County of Lancaster, Lecturer on Chemistry,
send greeting.
WHEREAS Her present Majesty Queen Victoria, by Her Letters Patent
under the Great Seal of the United Kingdom of Great Britain and Ireland,
bearing date at Westminster, the Twenty-fifth day of February now last
past, did give and grant unto me, the said John Wilson, Her especial licence,
full power, sole privilege and authority, that I, the said John Wilson, my
executors, administrators, and assigns, or such others as I, the said John
Wilson, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter 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, my Invention of "AN IMPROVEMENT OR IMPROVEMENTS IN THE PROCESS
OR PROCESSES OF MANUFACTURER THE CARBONATE OF SODA;" in which said Letters
Patent there is contained a proviso obliging me, the said John Wilson, by an
instrument in writing under my hand and seal, particularly to describe and
ascertain the nature of my said Invention, and in what manner the same is to
be performed, and to cause the same to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Wilson, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described
and ascertained as follows, that is to say :-
My improvements consist in the use of the bi-carbonate of soda and the
sesqui-carbonate of soda in preparing the common carbonate of soda. I obtain
the carbonate of soda from sulphuret of sodium by adding one equivalent
or eighty-five parts of bi-carbonate of soda to a solution of one equivalent
or forty-eight parts of sulphuret of sodium. On the application of heat sul-
phuretted hydrogen gas is evolved, and carbonate of soda remains. When
I wish to collect the sulphuretted hydrogen gas I conduct the above-mentioned
process in a flat iron pan, furnished with an iron cover, and made to fit the
pan or boiler by a water or sand lute, by means of a pipe connected with
the lid or cover. The sulphuretted hydrogen gas is conducted as it is
disengaged into a gas holder. When the sulphuretted hydrogen ceases to be
evolved the carbonate of soda is removed from the pan to a common white
ash furnace and heated to dryness. By dissolving this impure carbonate of
soda in water, and allowing the solution to settle, a clear solution is obtained,
which is afterwards concentrated by boiling, and then allowed to crystallize by
cooling, or the carbonate in a state of a protohydrate may be procured by
evaporating the solution when the carbonate of soda falls in the state of fine
salt. When I do not wish to collect the sulphuretted hydrogen gas which is
evolved during the decomposition of the solution of sulphuret of sodium I
effect the decomposition in a reverberatory furnace of the form usually termed
the white ash furnace. The mixture of bi-carbonate of soda and solution of
sulphuret of sodium must be well stirred until the mass becomes perfectly
dry. The impure carbonate of soda must then be treated as in the first-
mentioned process. When I decompose sulphate of soda in the usual manner
by heating it with a mixture of slack and lime or carbonate of lime, to the
solution obtained from the black ash, which is a mixture chiefly of carbonate
of soda and caustic soda, I add bi-carbonate of soda to convert the caustic
soda into the neutral carbonate of soda. The proportion of the bi-carbonate
of soda required in this process depends on the relative proportions of car-
bonate of soda and caustic soda contained in the black ash liquor. I find that
in general about one third of the soda contained in the solution exists in the
caustic state, and about one third of an equivalent of bi-carbonate of soda is
required for its saturation. To obtain the carbonate of soda in crystals I allow
the liquor, when it has obtained a specific gravity, about 1-270, or about 54°
of the common hydrometer, to settle, and afterwards decant the clear solution

page_text: into coolers of the usual form; or I obtain the carbonate in the state of a
fine salt by evaporating the solution. I also obtain carbonate of soda from
soda ash by dissolving the ash and saturating the caustic soda by means of
bi-carbonate of soda, and proceeding in the same manner as when the black
ash liquor is employed. In the above-mentioned processes the sesqui-carbonate
can be substituted for the bi-carbonate of soda, but two equivalents of sesqui-
carbonate are required instead of one eqivalent of the bi-carbonate. In the
above processes I claim the use of the bi-carbonate of soda and the sesqui-
carbonate of soda in preparing the carbonate of soda from a solution of
sulphuret of sodium. I also claim the use of the bi-carbonate and sesqui-
carbonate of soda in preparing the carbonate of soda from solution of black
ash or from soda ash.
In witness whereof, I, the said John Wilson, have hereunto set my
hand and seal, this Nineteenth day of August, in the year One
thousand eight hundred and forty