IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA, AND IN THE TREATMENT OF COMPOUNDS PRODUCED THEREIN
Year: 1873

page_text: LETTERS PATENT to Walter Weldon, of Abbey Lodge, Merton; in
the County of Surrey, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF CARBONATE OF SODA, AND IN THE TREATMENT OF
COMPOUNDS PRODUCED THEREIN."
-
ealed the 2nd April: 1874,, and dated the 22nd November 1873.
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the
Office of the Commissioners of Patents, with his Petition, on the
22nd November 1873:
I, WALTER WELDON, of Abbey Lodge, Merton, in the County of
Surrey, do hereby declare the nature of the said Invention for " IMPROVE-
MENTS IN THE MANUFACTURE OF CARBONATE OF SODA,, AND IN THE. TREATMENT OF.
COMPOUNDS PRODUCED THEREIN," to be as follows.:
I
My said Invention relates to the manufacture of carbonate of soda by
what is known as the ammonia process; it has for its objects to obtain
in an useful form the chlorine of the chloride of sodium treated by the
said process to recover for use indefinitely over and over again the reagent

page_text: used to regenerate the ammonia employed in the said process, and to
convey to the regenerated ammonia the carbonic acid of products of
combustion by means of an intermediary agent, in such wise as to
combine the ammonia with the carbonic acid of the products of com-
bustion while avoiding the loss and other inconveniences which result
when the ammonia itself is brought directly into contact therewith.
I accomplish these objects as follows:-For the decomposition of the
chloride of ammonium produced in the said process I employ artificial
carbonate of magnesia produced and indefinitely regenerated, as will be
herein-after described. The chloride of ammonium is obtained in the
said process in the state of aqueous solution. I prefer to boil this
solution with the artificial carbonate of magnesia in a vessel of the
nature of a still; I thus obtain a distillate of carbonate of ammonia and
a residual solution of chloride of magnesium. From the latter product
I obtain hydrochloric acid and regenerate carbonate of magnesia, as will
be herein-after described; the former I employ in conjunction with a
second equivalent of carbonic acid which I prefer should be that driven
off from a previously produced quantity of bicarbonate of soda, to
convert a further portion of chloride of sodium into bicarbonate of soda,
as will be well understood.
The solution of chloride of magnesium obtained as above described I
concentrate by evaporation down nearly to the point at which it would
begin to decompose, and I then run the concentrated solution into a
muffle furnace or other suitable apparatus, wherein by further heating I
drive off hydrochloric acid in the state of vapour, leaving free magnesia
behind. The hydrochloric acid I condense or otherwise apply, as will
be well understood, and the magnesia I treat by products of combustion,
thereby reproducing carbonate of magnesia for use again as before. In
thus decomposing the chloride of magnesium by heat alone, I prefer not
to décompose the whole of the charge but to have always in use such
quantity of the said chloride that I may obtain the quantity of magnesia
I require by decomposing it only partially. I have found that this
method of decomposing hydrated chloride of magnesium yields a much
more chemically active magnesia when the charge of chloride of
magnesium is decomposed only partially than when its decomposition is
carried to completeness.
When there is much chloride of sodium with the chloride of magne-
sium I prefer to remove as much as much as possible of the former

page_text: chloride by fishing it out from the concentrated solution, otherwise heat
alone will not decompose the chloride of magnesium, but will yield an
anhydrous double chloride of magnesium and sodium, to decompose the
chloride of magnesium in which will require that it should be heated in
a current of steam.
In converting into carbonate the magnesia resulting from the decom-
position of the chloride of magnesium produced by the reaction of car-
bonate of magnesia upon the chloride of ammonium obtained in the
manufacture of soda by the ammonia process, I can use carbonic acid
from any source, but I prefer to use that contained in products of com-
bustion as being the cheapest. I prefer to suspend the magnesia, or
mixture of magnesia, and undecomposed chloride or chlorides in water,
and either to inject the carbonic acid as contained in products of com-
bustion, or otherwise into the milk so produced, or to treat the said milk
thereby in an apparatus similar to that for the absorption of dilute
chlorine for which a Patent has been granted to me, bearing date the
16th day of July A.D. 1873.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Walter Weldon in the Great Seal Patent Office,
on the 21st May 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
WELDON, of Abbey Lodge, Merton, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of November, in the year
of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Walter Weldon, Her special
licence that I, the said Walter Weldon, my executors, administrators,
and assigns, or such others as I, the said Walter Weldon, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the

page_text: Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
the Manufacture of Carbonate OF SODA, AND IN THE TREATMENT OF COMPOUNDS ·
PRODUCED THEREIN," upon the condition (amongst others) that I, the said
Walter Weldon, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Walter Weldon, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement:-
My said Invention relates to the manufacture of carbonate of soda by
what is known as the ammonia process; it has for its objects to obtain in
an useful form the chlorine of the chloride of sodium treated by the said
process to recover for use indefinitely over and over again the reagent
used to regenerate the ammonia employed in the said process, and to
convey to the regenerated ammonia the carbonic acid of products of
combustion by means of an intermediary agent, in such wise as to
combine the ammonia with the carbonic acid of the products of com-
bustion while avoiding the loss and other inconveniences which result
when the ammonia itself is brought directly into contact therewith.
I accomplish these objects as follows:-For the decomposition of the
chloride of ammonium produced in the said process I employ artificial
carbonate of magnesia, produced and indefinitely regenerated, as will be
herein-after described. The chloride of ammonium is obtained in the
said process in the state of aqueous solution. I prefer to boil this
solution with the artificial carbonate of magnesia in a vessel of the
nature of a still; I thus obtain a distillate of carbonate of ammonia and
a residual solution of chloride of magnesium. From the latter product
I obtain hydrochloric acid, and regenerate carbonate of magnesia, as will
be herein-after described; the former I employ in conjunction with a
second equivalent of carbonic acid which I prefer should be that driven
off from a previously produced quantity of bicarbonate of soda to
convert a further portion of chloride of sodium into bicarbonate of soda,
as will be well understood.

page_text: The solution of chloride of magnesium obtained as above described I
concentrate by evaporation down nearly to the point at which it would
begin to decompose, and I then run the concentrated solution into a
muffle furnace or other suitable apparatus, wherein by further heating. I
5 drive off hydrochloric acid in the state of vapour, leaving free magnesia
behind. The hydrochloric acid I condense or otherwise apply, as will be
well understood; and the magnesia I treat by products of combustion,
thereby reproducing carbonate of magnesia for use again as before. In
thus decomposing the chloride of magnesium by heat alone I prefer not
) to decompose the whole of the charge, but to have always in use such
quantity of the said chloride that I may obtain the quantity of magnesia
I require by decomposing it only partially. I have found that this
method of decomposing hydrated chloride of magnesia yields a much more
chemically active magnesia when the charge of chloride of magnesium is
decomposed only partially than when its decomposition is carried to
completeness.
When there is much chloride of sodium with the chloride of
magnesium I prefer to remove as much as possible of the former
chloride by fishing it out from the concentrated solution, otherwise heat
alone will not decompose the chloride of magnesium, but will yield an
anhydrous double chloride of magnesium and sodium to decompose the
chloride of magnesium in which will require that it should be heated in
a current of steam.
In converting into carbonate the magnesia resulting from the decom-
position of the chloride of magnesium produced by the reaction of car-
bonate of magnesia upon the chloride of ammonium obtained in the
manufacture of soda by the ammonia process, I can use carbonic acid
from any source, but I prefer to use that contained in products of
combustion as being the cheapest. I prefer to suspend the magnesia or
mixture of magnesia, and undecomposed chloride or chlorides in water,
and either to inject the carbonic acid, as contained in the products of
combustion, or otherwise into the milk so produced, or to treat the said
milk thereby.in an apparatus similar to that for the absorption of dilute
chlorine for which a Patent has been granted to me, bearing date the
16th day of July, A.D. 1873.
Ha
1

page_text: claim as the Invention to be secured to me by the herein-before in part
recited Letters Patent, the improvements in the manufacture of soda
which are above described.
In witness whereof, I, the said Walter Weldon, have hereunto set
my hand and seal, this Twentieth day of May, in the year of our 5
Lord One thousand eight hundred and seventy-four.