Process for Obtaining Chlorine and Bromine by the Aid of Electricity.
Year: 1890

page_text: Date of Application, 26th July, 1890-Accepted, 13th Sept., 1890
Process for Obtaining Chlorine and Bromine by the Aid of
Electricity.
I, GEORG NAHNSEN of Nicolaistrasse, Hanover, in the German Empire, Chemist, 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:-
The halogens produced by electrolytic processes react somewhat easily on water
with formation of muriatic acids and compounds of chlorine and oxygen whereupon a
continuous and considerable loss of chlorine or electricity takes place. This loss
which according to circumstances may amount to ten per cent. and more is completely
and easily avoided by the process of this invention. The same consists in causing
the action of the electric current to take placo at a low temperature whoreby all
decomposing action of the halogens, especially chlorine, on water ceases. Although
this obtains at temperatures a few degrees above zero of Celsius it is however
desirable to operate at a lower temperature. In this way the operation is rendered
independent of the heat always being produced in the electrolyte upon the passage of
the current and there is further the advantage that chlorine is soluble in solutions
of low temperature to a smaller extent than in those of higher temperature.
To obtain chlorine all solutions containing chloride including muriatic acid, are
suitable. My process requires only, that, in order to keep the solutions in a fluid stato
at temperatures under zero of Celsius, they shall be used in a highly concentrated
form and maintained as continuously as possible at the same degree of concentration.
To this end it is necessary, when in the electrolytic process, a certain quantity of salt
has been withdrawn from the solutions to repeatedly enrich them with salt in the
course of the process and then subject them over again to the action of electricity.
The anode and cathode solutions in the decomposing cells, separated by porous
partitions, circulate from one decomposing cell to another and must also be con-
centrated each by itself in a special vessel, and is generally effected by bringing them
in contact with fixed pulverised salt which is stirred up in the concentrating vessels by
means of suitable stirring apparatus.
Lyes containing bromine become in the course of lengthy action enriched in
bromine, which upon a sufficient quantity thereof collecting is separated from the lye
without any further manipulation.
It is desirable to have the electrodes insoluble; for the anode, carbon is to be pre-
ferred. The tension about from 20 to 30 per cent. more than the theoretically calculated.
The density of current at the anode not under 0.25 ampère per square decimetre.
The solutions are cooled by means of refrigerating machinery. The vessels in
which the decomposition takes place are well coated with a material that is, a non-
conductor of heat. Over them there is arranged a hopper like device terminating in
a pipe by which the chlorine is drawn off and conducted away.
The chlorine thus obtained has the advantage that it is absolutely dry and free from
muriatic acid, and therefore is the material most suitable for the manufacture of
chloride of lime, etcetera.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim, is:
The process for obtaining chlorine and bromine by the aid of electricity, consisting

page_text: in considerably cooling the solutions of the halogen compounds and carrying out the
electrolysis at a low temperature, substantially as described.
Dated this 26th day of July 1890.
CAPITAINE & VON HERTLING,
89, Chancery Lane, London, W.C., Agents for the Applicant.

page_text: Date of Application, 26th July, 1390-Accepted, 13th Sept., 1890
Process for Obtaining Chlorine and Bromine by the Aid of
Electricity.
I, GEORG NAHNSEN of Nicolaistrasse, Hanover, in the German Empire, Chemist, 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:
The halogens produced by electrolytic processes react somewhat easily on water
with formation of muriatic acids and compounds of chlorine and oxygen whereupon a
continuous and considerable loss of chlorine or electricity Lakes place. This loss
which according to circumstances may amount to ten per cent, and more is completely
and easily avoided by the process of this invention. The same consists in causing
the action of the electric current to take place at a low temperature whereby all
decomposing action of the halogens, especially chlorine, on wator censes. Although
this obtains at temperatures a few degrees above zero of Celsius it is however
desirable to operate at a lower temperature. In this way the operation is rendered
independent of the heat always being produced in the electrolyte upon the passage of
the current and there is further the advantage that chlorine is soluble in solutions
of low temperature to a smaller extent than in those of higher temperature.
To obtain chlorine all solutions containing chloride including muriatic acid, are
suitable. My process requires only, that, in order to keep the solutions in a fluid stato
at temperatures under zoro of Celsius, they shall be used in a highly concentrated
form and maintained as continuously as possible at the same degree of concentration.
To this end it is necessary, when in the electrolytic process, a certain quantity of salt
has been withdrawn from the solutions to repeatedly enrich them with salt in the
course of the process and then subject them over again to the action of electricity.
The anode and cathode solutions in the decomposing cells, separated hy porous
partitions, circulate from one decomposing cell to another and must also be con-
centrated each by itself in a special vessel, and is generally effected by bringing them
in contact with fixed pulverised salt which is stirred up in the concentrating vossels by
means of suitable stirring apparatus.
Lyes containing bromine become in the course of lengthy action enriched in
bromine, which upon a sufficient quantity thereof collecting is separated from the lye
without any further manipulation.
It is desirable to have the electrodes insoluble; for the anode, carbon is to be pre-
ferred. The tension about from 20 to 30 per cent. more than the theoretically calculated.
The density of current at the anode not under 0-25 ampère per square decimetre.
The solutions are cooled by means of refrigerating machinery. The vessels in
which the decomposition takes place are well coated with a material that is a non-
conductor of heat. Over them there is arranged a hopper like device terminating in
a pipe by which the chlorine is drawn off and conducted away.
The chlorine thus obtained has the advantage that it is absolutely dry and free from
muriatic acid, and therefore is the material most suitable for the manufacture of
chloride of lime, etcetera.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to he performed, I declare that what I
claim, is:
The process for obtaining chlorine and bromine by the aid of electricity, consisting

page_text: in considerably cooling the solutions of the halogen compounds and carrying out the
electrolysis at a low temperature, substantially as described.
Dated this 26th day of July 1890.
CAPITAINE & VON HERTLING,
89, Chancery Lane, London, W.C., Agents for the Applicant.