Improvements in or relating to the Treatment of Sodium Chloride, and to the Method of Utilizing the Products in the Manufacture of White Lead, and of Soda, Chlorine, and their Derivatives.
Year: 1893

page_text: Date of Application, 10th July, 1893
Complete Specification Left, 22nd Mar., 1894-Accepted, 10th July, 1894
TRUVIDIONAL DI DITUALIUN.
Improvements in or relating to the Treatment of Sodium Chloride,
and to the Method of Utilizing the Products in the Manufacture
of White Lead, and of Soda, Chlorine, and their Derivatives.
I, REGINALD HADDAN, of the Firm of Herbert Haddan & Co., of
18 Buckingham Street, Strand, W.C., London, Patent Agent, do hereby declare
the nature of this invention a communication to me from abroad by Compagnie
Electro-chimique de St. Béron of
in the Republic of France, to be as
follows:-
The object of this invention is to utilize the chlorine and the sodium contained
in chloride of sodium without any waste and consequently cheaply. For this
purpose I subject the chloride of sodium to an electric current. The electro-
dialysing apparatus, which I use, may be grouped in any number of batteries, each
group having two electrolytes separated by a porous partition. The one of these
electrolytes in which the anode is immersed is left undisturbed and at rest and is
composed of a solution of chloride of sodium kept concentrated and rendered acid
by addition of hydrochloric acid. The chlorine which becomes discharged is
carried off by an exhaust for utilization. The other electrolyte containing the
cathode is composed of a solution of chloride of sodium more or less concentrated
but continuously increasing in contents of hydrate of soda under the action of the
current. This electrolyte is kept regularly circulating in the apparatus and is
allowed to flow out with a percentage contents of soda, regulated according to the
time during which the liquid is exposed to the action of the current. This
possibility of regulating the richness of the electrolyte in soda allows any of the
following products to be obtained.
1. Production of concentrated eau de Javelle or hypochlorite of soda.
The speed of flow of the electrolyte is regulated to obtain the percentage of soda,
corresponding to the strength of the eau de Javelle-water required. This solution is
run into a vessel, into which the gaseous chlorine arising from the decomposition of
the sodium chloride is passed. When the liquor has arrived at the desired
chlorometrical standard, the admission of the chlorine is cut off and the liquid is
drawn off, whereupon another bulk of solution may be treated in the same
manner.
2. Simultaneous production of soda, white lead, and derivatives of chlorine.
The apparatus is regulated so as to give a liquid containing about 120 grammes
of caustic soda per liter. This liquid is drawn off continuously by a pipe to the
bottom of a vessel containing litharge with which it is mixed by means of a
mechanical agitator. The solution of the litharge in the caustic soda is rendered
more complete by application of heat from a furnace under the vessel. The hot
solution flows off through an upper pipe into a series of carbonators or carbonating
apparatus traversed by a current of carbonic acid gas. The insoluble white lead is
precipitated and is separated by a filter press. The alkaline liquid on leaving the
filter press is passed into other carbonators. Bicarbonate of soda which is nearly
insoluble in the solution of chloride of sodium separates in crystals which are
removed from the mother liquor and dried. The mother liquor is returned to the
electro-dialysors to be again enriched with caustic soda.
The crystals of bicarbonate of soda may if desired be transformed into
carbonate.

page_text: 3. Production of bicarbonate of soda and chloride of lime.
The same process and apparatus permit of the production of crystals of carbonate
of soda and desired derivatives of chlorine by passing the alkaline liquid out of the
electro dialysor into the carbonators.
4. Production of a solution of hydrate of soda and gaseous chlorine.
In paper mills, cloth works, and other manufactures this apparatus will allow of the
utilization.
.
1. Under the form of lye of the solution of caustic soda concentrated or not.
2. As a bleaching reagent the chlorine developed either in the gaseous state or
under the form of hypo-chlorite.
;
4
COMPLETE SPECIFICATION.
Improvements in or relating to the Treatment of Sodium Chloride,
and to the Method of Utilizing the Products in the Manufacture
of White Lead, and of Soda, Chlorine, and their Derivatives.
J. REGINALD HADDAN of the Firm of Herbert Haddan & Co., of
18 Buckingham Street, Strand, London W.C. Patent Agent do hereby declare
the nature of this invention, a communication to me from abroad by Compagnie
Electro Chimique de St. Béron, of 189 Boulevard St. Germain, Paris, in the
Republic of France, and in what manner the same is to be performed, to be
☐ particularly described and ascertained in and by the following statement :-
G
:
.
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"
The object of this; invention is to utilize the chlorine and the sodium contained
in chloride of sodium, without any waste and consequently cheaply. For this
The electrolysing
purpose we subject the chloride of sodium to an electric current.
.apparatus which we use, may be grouped in any number of batteries each group
having two electrolytes separated by a porous partition. The one of these electro-
lytes in which the anode is immersed is left undisturbed and at rest and is composed
of a solution of chloride of sodium kept concentrated and rendered acid by addition
of hydrochloric acid. The chlorine which becomes discharged is carried off by an
exhaust for utilization. The other electrolyte containing the cathode, is composed
of a solution of chloride of sodium more or less concentrated, but continuously
increasing in contents of hydrate of soda under the action of the current. This
electrolyte is kept regularly circulating in the apparatus and is allowed to flow out
with a percentage contents of soda regulated according to the time during which
the liquid is exposed to the action of the current. This possibility. of regulating
the richness of the electrolyte in soda allows any of the following products to be
obtained...
1. Production of concentrated eau de Javelle or bypochlorite of soda.
The speed of flow of the electrolyte is regulated to obtain the percentage of soda
corresponding to the strength of the eau de Javelle required. This solution is
run into a vessel a (Fig. 1 of the annexed drawings) into which the gaseous chlorine
arising from the decomposition of the sodium chloride is passed. When the liquor
has arrived at the desired chlorometrical standard, the admission of the chlorine is
cut off at M and the liquid is drawn off at N, whereupon another bulk of solution
✓ may be treated in the same manner.
*.
=
2. Production of soda, white lead and of chlorine or its derivatives.
The apparatus is regulated so as to give a liquid containing about 120 grammes
of caustic soda per liter. This liquid is drawn off continuously by a pipe B to the
bottom of a vessel C (Fig. 2) containing litharge with which it is mixed by means
of a mechanical agitator D. The solution of the litharge in the caustic soda is
rendered more complete by application of heat from a furnace under the vessel.
The hot solution flows off through an upper pipe F into a series of carbonators or
carbonating apparatus G, G, traversed by a current of carbonic acid gas.

page_text: The insoluble white lead is precipitated and is separated by a filter press. The
alkaline liquid on leaving the filter press is passed into other carbonators K K.
Bi-carbonate of soda, which is nearly insoluble in the solution of chloride of sodium
separates in crystals, which are removed from the mother-liquor and dried. The
mother-liquor is returned to the electrolysing apparatus to be again enriched with
caustic soda. The crystals of bi-carbonate of soda may if desired be transformed
into carbonate. The chlorine is as aforesaid given off by the electrolysing
apparatus and may be converted into any desired derivatives of chlorine.
3. Production of carbonate of soda and chloride of lime.
The same process and apparatus permits of the production of crystals of carbonate
of soda and desired derivatives of chlorine by passing the alkaline liquid out of the
electrolysing apparatus into the carbonators.
4. Production of a solution of hydrate of soda and gaseous chlorine.
In paper mills, cloth works and other manufactures, this apparatus will allow of
the utilization
(a) Under the form of lye of the solution of caustic soda concentrated or not.
(b) As a bleaching re-agent the chlorine developed, either in the gaseous state
or under the form of hypochlorite.
The forms, dimensions and proportions of the apparatus may be varied without
departing from this invention.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
declai
claim is :-
B
-
1. The improved method of producing concentrated eau de Javelle by electro-
lytic decomposition of chloride of sodium into caustic soda and gaseous chlorine,.
and by recombining these two bodies under the form of hypochlorites of composition
varying according to will.
2. In the treating of paper pulp and fabrics, the preparation of the solution of
soda either concentrated or not and of chlorine in gaseous form or transformed into
hydrochlorite, substantially as herein described.
3. The production of white lead, of carbonate of soda and of chlorine by
electrolysis of a solution of chloride of soda, treatment of litharge with the
electrolytic solution of caustic soda (containing more or less sodium chloride) thus
produced, and carbonating the resulting solution.
4. The successive separation of the white lead and of the soda or of the soda
alone from an electrolytic solution of caustic soda obtained from sodium chloride
by simple carbonating of such solution after the treatment of litharge therewith or
without such treatment respectively.
5. The electrolysing apparatus as herein described and illustrated in the drawing
as an example wherein an alkaline electrolyte circulates through a series of negative
cells and an electrolyte acidulated with hydrochloric acid remains stationary in the
same positive cells.
6. The combination with the above described apparatus of the apparatus for
producing eau de Javelle or hypochlorite of soda.
7. The combination of carbonating apparatus with electrolysing apparatus
whereby the liquid may pass directly from the electrolysing apparatus to the
carbonating apparatus:
Dated this 22nd day of March 1894
R. HADDAN.