Improvements in the Manufacture or Production of Soda Crystals."
Year: 1893

page_text: Date of Application, 3rd May, 1893
Complete Specification Left, 3rd Feb., 1894-Accepted, 3rd Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture or Production of Soda Crystals."
We, HERBERT RACTIVAN BROWNE, of Roselea, Cadishead in the County of
Lancaster, Chemist, and MALCOLM GUTHRIE, of 76 Princes Road, Liverpool, in
the County of Lancaster, Gentleman, do hereby declare the nature of this invention:
to be as follows:-
By the electrolysis of sodic chloride, soda is obtained in the form of caustic soda,
whilst by the ammonia soda process it is obtained in the form of anhydrous
carbonate of soda. For many purposes however it is preferred to use soda in the
form of crystallized carbonate of soda, commonly called soda crystals.
Now this invention has reference to the manufacture or production of soda
crystals in a simple and economical manner from the caustic soda liquor obtained
by the electrolysis of brine, and the partially finished alkaline product obtained in
the ammonia-soda process.
For this purpose there is added in suitable proportion to the caustic soda liquor
obtained by the electrolysis of brine a mixture of monocarbonate and acid carbonate
of soda produced by heating the bicarbonate of soda obtained by the ammonia soda
process, to a suitable temperature say from about 80 to 100° C., until practically:
the whole of the ammonia present in the said bicarbonate of soda has been driven
off. In this way the caustic soda will be converted into monocarbonate of soda by:
reaction with the acid or bicarbonate of soda contained in the mixture, and from
the resulting liquor, monocarbonate of soda is obtained as soda crystals by:
crystallization in the ordinary or any suitable manner.
The proportions of the substances used are preferably such as to result in the
production of a liquor rich in monocarbonate of soda.
Dated this 2nd day of May 1893.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in the Manufacture or Production of Soda Crystals.
We, HERBERT RACTIVAN BROWNE, of Roselea, Cadishead, in the County of
Lancaster, Chemist, and MALCOLM GUTHRIE, of 76 Princes Road, Liverpool, in
the County of Lancaster, Gentleman, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :—
By the electrolysis of sodic chloride, soda is obtained in the form of caustic soda,
whilst by the ammonia soda process it is obtained in the form of anhydrous
carbonate of soda. For many purposes however it is preferred to use soda in the.
form of crystallized carbonate of soda, commonly called soda crystals.
Now this invention has reference to the manufacture or production of soda
crystals in a simple and economical manner from the caustic soda liquor obtained.
by the electrolysis of brine and the partially finished alkaline product obtained in
the ammonia-soda process.

page_text: For this purpose there is added in suitable proportion to the caustic soda liquor
obtained by the electrolysis of brine, a mixture of mono-carbonate and acid
carbonate of soda produced by heating the bi-carbonate of soda obtained by the
ammonia soda process, to a suitable temperature, say from about 80 to 100° C., until
practically the whole of the ammonia present in the said bi-carbonate of soda has
been driven off. In this way the caustic soda will be converted into mono-carbonate
of soda by reaction with the acid or bi-carbonate of soda contained in the mixture,
and from the resulting liquor, mono-carbonate of soda is obtained as soda crystals
by crystallization in the ordinary or any suitable manner.
The proportions of the substances used are preferably such as to result in the
production of a liquor rich in monocarbonate of soda.
Our invention may advantageously be carried out as follows:-The liquor
resulting from the electrolysis of brine and which contains caustic soda in solution
together with a proportion of undecomposed salt is introduced into a dissolving tank
and heated to about 50° C. To it is then added a mixture of monocarbonate and
bicarbonate of soda obtained by heating the bi-carbonate of soda of the ammonia
soda process as described, the quantity of the mixture used being such that the
caustic soda in the liquor will be wholly converted into monocarbonate of soda by
reaction with the. bi-carbonate of soda in the said mixture. This point can he
ascertained by any suitable tests such as by the addition of a drop of the liquor in
which the mixture has been dissolved, to a solution of silver nitrate when a black
or brown coloration of the solution will be produced when caustic soda is present,
but which coloration will cease to be produced when the proportion of mixture is
such that the caustic soda is wholly converted into monocarbonate.
To the mixture of liquor, and monocarbonate, and bi-carbonate of soda may
advantageously be added about (2%) two per cent. of sulphate of soda (salt cake),
and enough bleaching powder or bleach liquor to oxidise any colouring matter that
may be present.
The mixture is agitated in the dissolving tank for a suitable time, say about
three or four hours at the above mentioned temperature of 50° C., until the added
substances have been completely dissolved, and the liquor contains say about 26%
of mono-carbonate of soda. The insoluble portion is then removed, it may be by
Bettling, or by filtration, and the remaining liquor is run off into one or more
crystallizing pans where the main portion of the carbonate of soda will crystallize
out as decahydrated carbonate of soda (Na,CO₂. 10 H,O) technically known as
soda crystals. After crystallization has taken place, the supernatant liquor is run
off, and the crystals are dried in any convenient way as for example by draining
them, and then drying them in a centrifugal hydro-extractor.
By this invention not only can chlorine and soda crystals be produced in an
advantageous manner in works where the ammonia soda process is in operation, but
the great cost usually incurred in furnacing the bicarbonate of soda obtained by
such process, in order to convert the same directly and wholly into mono-carbonate
of soda, is considerably reduced...
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 what
we claim is :-
1. The manufacture of soda crystals by dissolving in caustic soda liquor obtained
by the electrolysis of brine, a mixture of mono-carbonate and bicarbonate of soda
produced by heating bicarbonate of soda, obtained by the ammonia soda process,
until practically the whole of the ammonia present therein has been driven off, and
crystallizing out from the solution thus obtained the resulting mono-carbonate of
soda substantially as herein described.
2. The berein described process of manufacturing soda crystals which consists in
heating the residual caustic soda liquor obtained by the electrolysis of brine, adding
to the heated liquor a mixture of mono-carbonate and bi-carbonate of soda produced
by heating bicarbonate of soda obtained by the ammonia soda process, also adding

page_text: sulphate of soda and a bleaching agent to said liquor, agitating the whole mass
whilst heated until the added substances have been dissolved, removing insoluble
matter, crystallizing out mono-carbonate of soda from the remaining solution, and
drying the resulting soda crystals substantially as herein described for the purpose
anasifed
Dated this 3rd day of February 1894.
For the Applicants,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.