Improved Process and Apparatus for the Electro-chemical Production of Bleaching Agents.
Year: 1892

page_text: Date of Application, 23th May, 1892
Complete Specification Left, 7th June, 1892-Accepted, 23rd July, 1892
PROVISIONAL SPECIFICATION.
Improved Process and Apparatus for the Electro-chemical Production
of Bleaching Agents.
I, CHARLES KELLNER, Director of The Kellner Partington Paper Pulp
Company Limited of Manchester, residing at Wasagasse 29, Vienna 1, Austria, do
hereby declare the nature of this invention to be as follows:-
The processes beretofore proposed or carried into practice for the production of
bleaching liquids by electrolysis, consisted either in allowing the ions liberated by
the splitting up of a metallic chloride such as magnesium chloride, sodium chloride,
or a mixture of the same, or formed by secondary processes, to act upon one
another. In the decomposing cell or vessel, (electrolizer) and thus to form
hypochlorites, or in allowing the chlorine separated by electrolysis from a chlorite
of an alkali, or a chlorite of an alkaline earth, all from hydrochloric acid, to be
absorbed by milk of lime.
The first process has as is well known the disadvantage that the hypochlorites
formed are partly reduced by the hydrogen liberated at the cathode, or that the
action of the current extends also to the hypochlorites that are already formed, and
converts the same into chlorates, which have as is also well known, no bleaching
power.
The second process in which the separated chlorine, is passed into milk of lime
is not only rather tedious but is also uneconomical, this latter fact being caused
mainly by reason that only in very rare cases, can the products formed at the
cathode be utilized and also because the milk of lime must be bought whilst ad
equivalent amount of dilute solution of caustic soda remains useless, and because
finally the electrolyte is lost and cannot be re-introduced into the cycle of the
bleaching operations.
The present invention relates to a process in which all these disadvantages are
obviated. The said process has the following advantages :—
(a) Bleaching solutions of any desired strength can be produced;
(6) The current is completely utilized that is to say the electro-chemical
equivalent is entirely attained;
(c) No base need be purchased for the formation of hypochlorite ;
(d) The same electrolyte can be employed over and over again; and
(e) The apparatus employed is extremely simple and durable.
According to this invention the ions separated by the electrolysis of a metallic
chloride are brought into contact with one another outside of the decomposing cell
for the formation of hypochlorite, this being effected by allowing the chlorine to
pass off in gaseous form and then of causing it to be absorbed by the solution of a
metallic hydrate coming from the cathode compartments.
This absorption can be effected either by drawing or forcing the chlorine through
an alkaline solution, or by causing an alkaline solution to trickle in a fine state of
subdivision towards the chlorine.
The chlorine-containing liquid coming from the anode compartments of the
decomposing apparatus may also be mingled outside of the apparatus with the
liquid passing out of the cathode compartments, but the above stated employment
of the gaseous chlorine is preferable. In any case however the alkaline liquid
passing from the cathodes must be subjected to violent motion in order that all the
bubbles of hydrogen shall be expelled before the liquid is brought into contact with
the chlorine gas.
The apparatus hereinafter described and illustrated diagrammatically in Figs. 12
and 3 of the accompanying drawings, can advantageously be employed in carrying
Lout this pronsse

page_text: The electrolyte conveyed from the vessel A through the electrolytical decom-
posing vessel B, and which electrolyte. may receive an addition of acid for the
purpose of increasing its conductivity, is decomposed in the decomposing vessel into
chlorine gas and caustic soda. For this purpose any effective decomposing vessel
of any suitable construction can be employed.
The chlorine gas issuing from the electrolytical decomposing vessel, passes
through a pipe R into the bottom of an absorption tower C which contains pieces
of suitable material C' such as brick, clay or glass balls, that serve to distribute or
spread the alkaline that is caused to trickle down from above, and which is capable
of withstanding the action of chlorine gas.
The alkaline liquid coming from the cathode compartments and containing the
separated caustic soda, passes through a pipe R² into a box D in which it is very
violently agitated by means of agitators 99', whereby any bubbles of hydrogen gas
that may have been carried over with it, are removed.
The alkaline liquid then flows through a pipe R³ to a rose E and trickles
downward over the material C' in the tower C and flows off as finished bleaching
liquid into the vessel. The chlorine gas which is not absorbed in the tower
passes through a pipe R to a water jet blower or injector y into which it is drawn
by liquid that is raised by a pump H from a vessel J, and is forced together with
this forcing liquid below the level of the liquid in the vessel J for the purpose of
ensuring its being absorbed by such liquid.
Instead of working the injector by means of the pump H, compressed air may be
employed for drawing the chlorine gas from the electric decomposing apparatus and
forcing the same into the liquid coming from the cathode compartments.
In paper mills or pulp mills the vessel J may be employed with advantage for the
preliminary bleaching process, by charging the same with the paper pulp that is to
he subsequently bleached. It may however be also employed directly for the
production of hypochlorite, by filling it at first with only so much liquid as will
allow the pump to just feed the injector and draw by means of the latter the
chlorine directly from the decomposing cell, whilst the caustic soda is supplied to
the suction pipe of the pump by a branch pipe, for which purpose the pipé
connections R and R indicated in dotted lines, would be suitable.
The same arrangement may of course be employed also in the case of the goods
to be bleached, as indicated in Fig. 2, in which K represents a pulp engine the
partition K of which is prolonged on one side up to the end of the trough.
In the case of textile materials it will be understood that the pulp engines are
replaced by bleaching vats having perforated false bottoms.
The liquid drawn off after the termination of the bleaching process, can be again
subjected to electrical decomposition.
Dated this 28th day of May 1892.
CHARLES KELLNER,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improved Process and Apparatus for the Electro-chemical Production
of Bleaching Agents.
I, CHARLES KELLNER, Director of The Kellner-Partington Paper Pulp
Company Limited of Manchester, residing at Wasagasse 29, Vienna I, Austria, 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 processes heretofore proposed or carried into practice for the production of
bleaching liquids by electrolysis, consisted either in allowing the ions liberated by
the splitting up of a metallic chloride such as magnesium chloride, sodium chloride,
or a mixture of the same, or formed by secondary processes, to act upon one another
.
7

page_text: in the decomposing cell or vessel ("electroliser") and thus to form hypochlorites,
or in allowing the chlorine separated by electrolysis from a chloride of an alkali, or
a chloride of an alkaline earth, or from hydrochloric acid, to be absorbed by milk
of lime.
The first process. has, as is well known, the disadvantage that the hypochlorites
formed are partly reduced by the hydrogen liberated at the cathode, or that the
action of the current extends also to the hypochlorites that are already formed, and
converts the same into chlorates, which have as is also well known, no bleaching
power.
The second process in which the separated chlorine is passed into milk of lime is
not only rather tedious, but is also uneconomical, this latter fact being caused mainly
by reason that only in very rare cases can the products formed at the cathode be
utilized, and also because the milk of lime must be bought, whilst an equivalent
amount of dilute solution of caustic soda remains useless, and because finally the
electrolyte is lost and cannot be re-introduced into the cycle of the bleaching
operations.
The present invention relates to a process in which all these disadvantages are
obviated. The said process has the following advantages :-
(a) Bleaching solutions of any desired strength can be produced;
(b) The current is completely utilized, that is to say the electro-chemical
equivalent is entirely attained;
(c) No base need be purchased for the formation of hypochlorite;
(d) The same electrolyte can be employed over and over again; and
(e) The apparatus employed is extremely simple and durable.
According to this invention the ions separated by the electrolysis of a metallic
chloride are brought into contact with one another outside of the decomposing cell
for the formation of hypochlorite, this being effected by allowing the chlorine to
pass off in gaseous form and then causing it to be absorbed by the solution of a
metallic hydrate coming from the cathode compartments.
This absorption can be effected either by drawing or forcing the chlorine through
an alkaline solution, or by causing an alkaline solution to trickle in a fine state of
subdivision towards the chlorine.
The chlorine-containing liquid coming from the anode compartments of the
decomposing apparatus may also be mingled outside of the apparatus with the liquid
passing out of the cathode compartments, but the above stated employment of the
gaseous chlorine is preferable. In any case however the alkaline liquid passing
from the cathodes must be subjected to violent motion in order that all the bubbles
of hydrogen shall be expelled before the liquid is brought into contact with the
chlorine gas.
The apparatus hereinafter described and illustrated diagrammatically in Figs. 1, 2
and 3 of the drawings filed with my Provisional Specification, can advantageously
be employed in carrying out this process.
The electrolyte conveyed from the vessel A through the electrolytical decomposing
vessel B, and which electrolyte may receive an addition of acid for the purpose of
increasing its conductivity, is decomposed in the decomposing vessel into chlorine
gas and caustic soda. For this purpose a decomposing vessel of any suitable
construction can be employed.
The chlorine gas issuing from the electrolytical decomposing vessel, passes
through a pipe R' into the bottom of an absorption tower C which contains pieces
of suitable material C' such as brick, clay or glass balls, that serve to distribute or
spread the alkaline liquid that is caused to trickle down from above, and which is
capable of withstanding the action of chlorine gas.
The alkaline liquid coming from the cathode compartments and containing the
separated caustic soda, passes through a pipe R2 into a box D in which it is very
violently agitated by means of agitators 99', whereby any bubbles of hydrogen gas
that may have been carried over with-it, are removed.
The alkaline liquid then flows through a pipe R³ to a rose E and trickles' down-
.

page_text: passes
ward over the material C¹ in the tower C and flows off as finished bleaching liquid
into the vessel f. The chlorine gas which is not absorbed in the tower
through a pipe R to a water jet blower or injector g into which it is drawn by
liquid that is raised by a pump H from a vessel J, and is forced together with this
forcing liquid below the level of the liquid in the vessel J, for the purpose of
-ensuring its being absorbed by such liquid.
Instead of working the injector by means of the pump H, compressed air may be
-employed for drawing the chlorine gas from the electric decomposing apparatus and
forcing the same into the liquid coming from the cathode compartments.
In paper mills or pulp mills the vessel J may be employed with advantage for
the preliminary bleaching process, by charging the same with the paper puip that
is to be subsequently bleached. It may however be also employed directly for the
production of hypochlorite, by filling it at first with only so much liquid as will
allow the pump to just feed the injector and draw by means of the latter the chlorine
directly from the decomposing cell, whilst the caustic soda is supplied to the
suction pipe of the pump by a branch pipe, for which purpose the pipe
connections R and R indicated in dotted lines, would be suitable.
The same arrangement may of course be employed also in the case of the goods
to be bleached, as indicated in Fig. 2, in which K represents a pulp engine the
partition K' of which is prolonged on one side up to the end of the trough.
In the case of textile materials it will be understood that the pulp engines are
replaced by bleaching vats having perforated false bottoms.
The liquid drawn off after the termination of the bleaching process, can be again
subjected to electrical decomposition.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
-claim is:
1. The herein described process for producing bleaching liquid, according to
which a metallic chloride either alone, or with an addition of acid for increasing its
conductivity, is subjected to electrolysis, and the chlorine thus separated in a
gaseous condition is absorbed outside of the electrolytical decomposing apparatus
by an alkaline liquid also formed within and passing from the cathode compart-
ments of the said apparatus, the absorption being effected in the presence of
materials to be bleached, or not as may be desired.
2. For carrying out the process referred to in the preceding claim, the com-
bination with an electrolytical decomposing apparatus, of a spraying or trickling
apparatus in which the two ions produced by electrolysis are brought as opposed
currents into contact with each other outside of the electrolytical decomposing
apparatus, so that the electrolytically-produced chlorine gas is conducted towards
the finely distributed cathode liquid so as to be absorbed by the latter as set
forth.
3. For carrying out the process referred to in Claim 1, the combination with an
electrolytical decomposing apparatus and an absorbing apparatus, of a blower or
injector operated either by liquid supplied by a pump or by compressed air, and
serving to draw the chlorine from the electrolytical decomposing apparatus and to
force it into the liquid coming from the cathode compartments of such apparatus
substantially as described.
4. Apparatus constructed arranged and operating substantially as hereinbefore
described with reference, to and shown in Fig. 1, and in Figs. 2 and 3 of the
drawings for the purpose specified.
L 1
T
1000
C. KELLNER,
By L. W., per F. B.