A New or Improved Sodium Product and Method or Methods of Manufacturing the same.
Year: 1886

page_text: Date of Application, 12th Oct., 1886.
Complete Left, 2nd July, 1887.
Complete Accepted, 9th Aug., 1887.
A New or Improved Sodium Product and Method or Methods of
Manufacturing the same.
We, JOHN ISAAC WATTS and WILLIAM ARMSTRONG RICHARDS both of Sandbach,
in the County of Chester, Manufacturing Chemists, do hereby declare the nature
of this invention to be as follows:-
This invention consists mainly in the artificial production on a manufacturing scale
of a compound of sodium mono-carbonate and sodium bicarbonate with the elements
of water, styled sodium sesqui-carbonate. The compound prepared by our processes
is obtained in distinct crystals which can be dried by vacuum filters, filter presses
centrifugal machines or any other well known means, and then if required further
dried by the application of a low heat in any suitable apparatus, and afterwards
dressed in the usual manner. The crystals do not effloresce in the air. We are able
to produce the compound by a variety of methods; but the one which we prefer
is by adding crude bicarbonate of soda, as obtained in an ammonia soda process
to a hot solution of sodium mono-carbonate (or other decarbonating medium) and
then allowing the salt to crystallise out.
Among other, but less desirable variations of this method of preparing the product
when a solution of sodium, mono-carbonate is not used, are-
1. Adding crude bicarbonate of soda, as obtained in an ammonia soda process,
to melted soda crystals.
2. Boiling bicarbonate of soda with an amount of water insufficient to dissolve it.
In this case the first product obtained on cooling the liquor consists of bicarbonate of
soda. This can be separated either by crystallisation or salting out. After the
removal of the bicarbonate the new product can be obtained either by further
crystallisation or by salting out.
3. Boiling licarbonate of soda with a solution of caustic ammonia.
4. Heating the crude bicarbonate as manufactured in an ammonia soda process by
any well known means until the ammonia and a portion of the carbonic acid are given
off, and then dissolving the material thus obtained in water and, after separating any
bicarbonate of soda as in method (2), crytallising out the sesqui-carbonate.

page_text: 5. Heating crude bicarbonate as obtained in an ammonia soda process at 100
degrees Centigrade and then dissolving and separating as in method (2).
6. Heating crude bicarbonate of soda with water and caustic lime.
In all those cases where the product is salted out the mother liquor can be used
instead of brine in an ammonia soda process. In all cases where salt is not added
the mother liquor can be used over again for mixture with fresh bicarbonate, or can
be used for the production of soda crystals or for washing the bicarbonate in
an ammonia soda process.
In each case where the crude bicarbonate from an ammonia soda process is
employed the ammonia and carbonic acid gas evolved on heating can be collected
in any suitable apparatus. The bicarbonate that crystallises out can be dried and
treated like that obtained in Mond and Jarmay's process.

page_text: Manufacturing the same.
We JOHN ISAAC WATTS and WILLIAM ARMSTRONG RICHARDS both of Sandbach,
in the county of Chester, Manufacturing chemists, do hereby declare the nature of
this invention and in what manner the same is to be performed, to he particularly
described and ascertained in and by the following statement:-
This invention has for its object the production of a new article of manufacture
which we call "sesqui-carbonate of soda, and which is composed mainly of one
equivalent of bicarbonate of soda, one equivalent of monocarbonate of soda, and two
equivalents of water in chemical combination. [Na, CO,. Na HCO3. 2 H, Ó.]
Our method of manufacturing this salt consists in forming an aqueous solution,
containing three equivalents of soda to four (or between three and four) equivalents of
carbonic acid, and crystallising out at a temperature not below 35 degrees centigrade.
There are several different methods of obtaining the solution. We prefer to form
it by treating bicarbonate of soda in such manner as to deprive it of about one-third
of its carbonic acid, or by mixing it in solution with a chemically equivalent quantity
of monocarbonate of soda. The monocarbonate can be a little in excess, but not the
bicarbonate, or the excess of bicarbonate will be found in the product.
In carrying out the invention into practice we have found the following methods
of preparing the solution, all cheap and practicable, we give them in the order
in which we prefer them.
(a) We heat bicarbonate of soda by any well-known means, in such a manner
as to deprive it of about one third of its carbonic acid, we then dissolve the salt thus
treated in hot water.
(b) Or to a solution of monocarbonate of soda, we add the equivalent quantity
of bicarbonate of soda, that is, about 84 parts of bicarbonate of soda are added
to about every 106 parts of monocarbonate of soda.
(c) Or we boil bicarbonate of soda with water until one third of the carbonic acid
is given off.
(d) Or we treat bicarbonate of soda with caustic alkali sufficient to form the
requisite amount of monocarbonate of soda to combine with the remaining bicarbonate
of soda in the proportion of about 106 parts of monocarbonate to 84 parts of
bicarbonate.
(e) Or we treat bicarbonate of soda in solution with the oxide of any alkaline earth
in sufficient quantity to combine with about one third of the carbonic acid present.
Besides the alkaline earths, there are other substances that will unite with carbonic
acid that could be used for this purpose, but except in the rare case where it is desired
to form a special carbonate in this way and obtain the "sesquicarbonate"
bye-product, they are too expensive for commercial use so it is needless to enumerate
them.
as a
The solution obtained by any of these methods is clarified if necessary and slowly
cooled, preferably while it is kept agitated, when the sesqui-carbonate crystallizes out ;
but the temperature of the solution must not be allowed to fall below 35 degrees

page_text: centigrade, as below this temperature other carbonates of soda crystallize out from
the liquor. If the solution as obtained is not fully saturated it can be concentrated
by evaporation before submitting it to crystallization. Sodium chloride can be
added to the solution to accelerate the crystallisation if desired.
In cases where sodium chloride is not added the mother liquor can be used in
subsequent operations instead of water.
:
The sesquicarbonate of soda" is obtained in the form of distinct crystals, and can
be separated from the mother liquor and dried, by filter presses, hydro-extractors, or
any other well known means.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, we declare, that we are aware that a
native crystalline substance has been found in an impure form called sesquicarbonate
of soda, and that it has been known as a scientific fact that under certain circum-
stances, a crystalline carbonate of soda has been formed differing from both sodium
monocarbonate, and sodium bicarbonate, in the proportions of carbonic acid and soda
found therein; but these substances differ materially in chemical composition from
the product manufactured by our process, for while, according to the best authorities,
the substance which has hitherto been known, contains three equivalents of carbonic
acid to two equivalents of soda, our compound contains four equivalents of carbonic
acid to three equivalents of soda. Our new compound, therefore, contains considerably
less bicarbonate of soda, and is consequently much more valuable for numerous
industrial purposes. We have, without hesitation, given it commercially the same
name (sesquicarbonate of soda) because the product previously prepared has never
been made on a large scale, and is not now an article of commerce. But we declare
that what we claim as our invention is :-
-
1st. A new article of commerce, composed mainly of a salt containing one
equivalent of bicarbonate of soda, one equivalent of monocarbonate of soda, and two
equivalents of water (Na HCO, Na, (O, 2 H, 0).
2nd. The manufacture of the said salt by forming a solution containing three
equivalents of soda to four, or between three and four equivalents of carbonic acid,
and crystallising out at a temperature not below 35 degrees centigrade.
3rd. The manufacture of the solution set forth in claim 2, by any of the following
methods, and afterwards crystallising out the " sesquicarbonate substantially as
described,
(a) by heating bicarbonate of soda until about one third of the carbonic acid
is driven off, and dissolving in water.
(b) by mixing about 84 parts of bicarbonate of soda with about 106 parts of
monocarbonate of soda, dissolving the mixture in water.
(c) by boiling bicarbonate of soda with water, until about one third of the
carbonic acid is given off.
(d) by adding caustic alkali to bicarbonate of soda in sufficient quantity to
obtain a mixture of carbonates containing about 106 parts of monocarbonate
to 84 parts of bicarbonate.
(e) by adding the oxide of an alkaline earth (or other substance, capable of
combining with carbonic acid) to bicarbonate of soda in sufficient quantity to
combine with one third of its carbonic acid.
Dated this First day of July 1887
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicants.