IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
1
I CHARLES WIGG of Walmer Buildings Water Street Liverpool in the County of
Lancaster Manufacturing Chemist, do hereby declare the nature of my said invention
for "IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA to be as
follows:-
"
At present the greater part of the carbonate of soda of commerce is manufactured
either by the old Leblanc or the newer ammonia soda process.
The latter process
although the more economical so far as the production of soda is concerned does not
utilize the chlorine of the salt decomposed for the manufacture of Hydrochloric
acid, but allows all the chlorine to run to waste in the form of chloride of calcium
in solution. It is true that hydrochloric acid can be obtained from this residual
chloride.of calcium, but only by the use of comparatively expensive means and
particular plant. The special feature of the process I am about to describe
is that I am enabled thereby to obtain Hydrochloric acid in an earlier stage of the
manufacture of soda and with the ordinary plant possessed by every Leblanc
Manufacturer. This advantage I gain by the decomposition of sulphate of soda
in place of common salt by a method which I believe is novel and peculiar to
myself and by which I am enabled to secure Hydrochloric acid as the first stage in
the manufacture of soda. For the purposes of my invention I use the apparatus
constructed in accordance with British Letters Patent N° 3125 granted to me
I manipulate this apparatus and carry out my invention substantially as follows:-
(A) I treat common salt for the production of sulphate of soda either by the
ordinary Pot process or by the well known Hargreaves and Robinson process, the
Hydrochloric acid given off being condensed in the usual manner.
(B) I add the sulphate of soda so produced to a strong solution of carbonate of
ammonia prepared in the first saturator of the series by the passage therein of
ammonia and carbonic acid gases together or alternately. The solution of carbonate
of ammonia may contain 10% or thereabouts of ammonia, and the sulphate of
soda is added in solid powder or otherwise in quantity equivalent to three fourths
of the total ammonia present in the solution.
(C) I heat the mixture of carbonate of ammonia and sulphate of soda in the
saturator by the passage of steam or other heated gas or liquid through the hollow
rotating beaters of my apparatus till its contents have attained that temperature
at which the maximum amount of sulphate of soda enters into solution. During
this operation the saturator is kept closed and under pressure,

page_text: (D) The solution is allowed to cool of itself or may be cooled by the passage of
a refrigerating fluid through the hollow beaters before mentioned. The impurities
precipitated may be allowed to settle and then be removed.
(E) I pass carbonic acid gas into the solution until all the ammonia carbonate is
converted into bi carbonate. Bi-carbonate of soda is thereby precipitated and
sulphate of ammonia enters into solution.
(F) I separate the bi-carbonate of soda from the sulphate of ammonia by
filtration.
(G) I evaporate. the filtrate to obtain sulphate of ammonia crystals suitable for
sale as such, or I may. treat the sulphate of ammonia solution with brine or common
salt and boil down. By this means I procure a precipitation of an anhydrous
sulphate of soda, free from iron, and a solution of chloride of ammonia from which
latter ammonia may be redeemed for re-use.
(H) I roast the bi carbonate of soda in a suitable furnace to convert it into.
carbonate of soda, or I may dissolve it in hot water to form crystal soda,
In either operation I recover the carbonic acid given off for re-use in the
manufacture.
It will be seen from the above description that by my improved process I obtain
not only Hydrochloric acid cheaply for the manufacture of Bleaching Powder
but also sulphate of ammonia a valuable article of commerce as a bye product
or a purified sulphate of Soda.

page_text: :
I CHARLES WIGG of Walmer Buildings Water Street, Liverpool, in the County
of Lancaster do hereby declare the nature of the said invention for "IMPROVEMENTS
IN THE MANUFACTURE OF CARBONATE OF SODA" and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
At present the greater part of the Carbonate of soda of commerce is manufactured
either by the old Leblanc or the newer ammonia soda process.
The latter process
although the more economical so far as the production of soda is concerned does
not utilize the chlorine of the salt decomposed for the manufacture of Hydrochloric
acid, but allows all the chlorine to run to waste in the form of chloride of calcium
in solution. It is true that hydrochloric acid can be obtained from this residual
chloride of calcium but, only by the use of comparatively expensive means and
particular plant. The special feature of the process I am about to describe is that I am
enabled thereby to obtain Hydrochloric acid in an earlier stage of the manufacture
of Soda and with the ordinary plant possessed by every Leblanc Manufacturer.
This advantage I gain by the decomposition of sulphate of soda in place of common
salt by a method which I believe is novel and peculiar to myself and by which I am
enabled to secure Hydrochloric acid as the first stage in the manufacture of soda.
For the purposes of my invention I use the apparatus constructed in accordance with
British Letters Patent No 3125 of the year 1882 granted to me. I manipulate this
apparatus and carry out my invention substantially as follows.
(A) I treat common salt for the production of sulphate of soda either by the
ordinary Pot process or by the well known Hargreaves and Robinson process, the
Hydrochloric acid given off being condensed in the usual manner.
(B) I add the sulphate of soda so produced to a strong solution of ammonia or
carbonate of ammonia prepared in the first saturator of the series by the passage
therein of ammonia and carbonic acid gases together or alternately. The solution
of carbonate of ammonia may contain 10% or thereabouts of ammonia and the
sulphate of soda is added in solid powder or otherwise in quantity equivalent to
three fourths of the total ammonia present in the solution.
(C) I may beat the mixture of carbonate of ammonia and sulphate of soda in
the saturator by the passage of steam or other heated gas or liquid through the
hollow rotating beaters of my apparatus till its contents have attained that
temperature at which the maximum amount of sulphate of soda enters into
solution, but under ordinary circumstances heat is not necessary. During this
operation the saturator is kept closed and under pressure.
(D) The solution is allowed to cool of itself, or may be cooled by the passage of a
refrigerating fluid through the hollow beaters before mentioned. The impurities
precipitated may be allowed to settle and then be moved.
(E) I pass carbonic acid gas into the solution under a pressure of from 15 to 40 lbs
until all the ammonia carbonate is converted into bi carbonate. Bi carbonate of
soda is thereby precipitated and sulphate of ammonia enters into solution.
(F) I separate the bi carbonate of soda from the sulphate of ammonia by
filtration first through cloth and afterwards through gypsum so as to ensure that

page_text: the carbonate of ammonia which has not entered into reaction with the sulphate of
soda shall be decomposed into sulphate of ammonia.
(G) I evaporate the filtrate to obtain sulphate of ammonia crystals suitable for
sale as such, or I may treat the sulphate of ammonia solution with brine or common
salt and boil down. By this means I procure a precipitation of an anhydrous
sulphate of soda, free from iron, and a solution of chloride of.ammonia from which
latter ammonia may be redeemed for re-use, or the chloride of ammonia may be
crystallized. The anhydrous sulphate of soda obtained as above set forth may be
converted into crystals of Glaubers salt.
(H) I roast the bi-carbonate of soda in a suitable furnace to convert it into
carbonate of soda, or I may dissolve it in hot water, with or without lime to form
crystal soda. In either operation I recover the carbonic acid given off for reuse in
the manufacture.
It will be seen from the above description that by my improved process I obtain
not only Hydrochloric acid cheaply for the manufacture of Bleaching Powder but
also sulphate of ammonia a valuable article of commerce as a bye product, or a
purified sulphate of soda.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
First. The manufacture of carbonate of soda by the process herein setforth.
Second. The manufacture of carbonate of soda from sulpbate of soda in
apparatus substantially as setforth.
Third. The double filtration in the manufacture of carbonate of soda substantially
as herein setforth under head F for the purpose specified.
Fourth. In the manufacture of carbonate of soda under my invention obtaining
sulphate of ammonia, ammonia or chloride of ammonia and sulphate of soda or
Glaubers salt substantially as setforth under part H.
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