Improvements relating to Electrolysis, and to Apparatus therefor.
Year: 1894

page_text: Date of Application, 10th July, 1894-Accepted, 24th Nov., 1894
COMPLETE SPECIFICATION.
[Communicated from abroad by ISAIAH LEWIS ROBERTS, of the City of Brooklyn,
County of Kings and State of New York, United States of America,
Chemist.]
Improvements relating to Electrolysis, and to Apparatus therefor.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents; 45 Southampton Buildings, in the County of Middlesex, 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 general object of my invention is the separation by means of electricity-
that is, by means of the electric current flowing through them-of various liquids
or electrolytes into two or more of their component parts.
The special use to which I propose to put my apparatus is the decomposition of
alkaline solutions, such, for instance, as chloride of sodium containing a base and
an acid radical combined therewith, into such base and acid, making, if desired,
subsequent combinations in the apparatus of such separated parts.
The apparatus, to be more specific, will be found specially useful for the
manufacture of chlorine and caustic soda from common salt.
In the Specification of a Patent No. 20111 December 9th 1890 granted to
Roberts & McGraw as in the present one, the apparatus is divided by means of a
separating partition into two compartments called the anode and cathode chambers,
and in my earlier processes 1 have succeeded in transferring the acid radical
through the dividing partition by the means of the action of electrolysis.
So far as my principal process is concerned, my present invention relates to the
discovery that the reverse action can be successfully and economically carried
out. In the electrolysis of chloride of sodium according to my old process, there
is a constant decrease in the output of chlorine and alkali as the strength of the
chloride solution decreases and the alkali increases. I have found that this is
largely due to the fact that in the tanks where no solution is carried next to the
anode no base was present. By my present process I keep a continuous supply of
a solution of sodium chloride or other similar solution desired to be electrolyzed in
the anode chamber, so that the bases may be supplied as fast as they are
transferred to the other compartment, generally in this apparatus the outer
compartment.
In this device, employed in the treatment of chloride of sodium or other
substances, in which the base is transferred to the cathode compartment, the sodium
base combining with the water forms sodic hydrate, which, when sufficiently
concentrated, may be drawn off, and the sodium chloride may be constantly
supplied to the anode compartment and the base constantly transferred through the
partition.
This method of electrolysis I believe to be broadly new, and my invention.
I have further devised special forms of apparatus for carrying out this process
successfully and economically, and especially I have devised a new form of partition,
in which a gelatinizable substance is mingled with the carbon substance of the
partition so as to form a self-sustaining partition, the details of which will be more
fully described hereafter.
I have also devised a partition composed of finely divided particles of the salt
itself which may serve instead of the last-named partition to divide the anode and
cathode chambers, and for some uses I find this partition expedient, but it has the

page_text: disadvantage of causing a solution of the salt to be mingled with the solution of
the body formed from the transferred base.
I will now proceed to describe an apparatus for carrying my process into effect.
Fig. I and Sheet I, of the accompanying drawings illustrates in central vertical
section modified forms of decomposition cells by means of which I carry out my
improved process of electro-decomposition.
Referring to Fig. 1, A is a tank or vessel, preferably of metal, such as iron, in
order that it may serve as the cathode..
C is a bag composed generally of wire netting and cloth or asbestos fabric,
which is secured to a metal ring D that rests on the edges of an opening in the
cover of the tank and supports the bag C and its contents in the tank.
E is the diaphragm or partition of silica, powdered anthracite coal or similar
material contained between the two supporting walls formed by the bag C and a
perforated or porous jar F, having openings R, which may be ordinary unglazed
porcelain.
His a mass of the crystals of the salt to be decomposed, and I is an anode of
conducting charcoal or carbon.
J'is a cover made of a block of wood or preferably an unglazed terra-cotta tile
soaked in hot paraffine to fill the pores. This tile contains three holes, one for the
passage of the anode I, another for a gas vent, as K, and a third for a long
tube L, through which a supply of salt crystals is introduced into the anode
compartiment.
N, is an annular collar riveted to or cast on the top of tank A, and M is a luting
or seal of wax or other proper material that closes the tank.
O, is a ring of glass, hard rubber, glazed tile or the like, that is used to more
effectively insulate the material of the diaphragm E from the tank A.
In making the diaphragm E, I proceed as follows: 1 first grind anthracite coal
or other material which is a non-conductor, or a comparatively poor conductor, of
electricity, and which will not be dissolved nor chemically attacked by the products
of decomposition, by preference reducing the same to such a fiue state of sub-
division as to constitute a practically amorphous body. I also prepare a solution
of silicate of soda or potash of a strength of about 25° or 30° Baumé, and about
two or three per cent. of caustic soda or potash. The latter is employed to prevent
the coagulation of the silicic acid by the sulphur, or any metallic salts which may
be present as impurities in the powdered coal or other material, and which would
tend to impair the homogeneity of the diaphragm and weaken it.
The apparatus shown in Figure 1 can then be readily put together by making
a stiff paste of coal dust by mixing it with the above solution. This I place in the
bottom of the suspended bag C around the tube T. Then the perforated jar F
is placed in position and the anthracite paste packed in around it. Upon the upper
part of this some broken pieces of anthracite may be placed, as shown. The
porous jar F may then be filled around the carbon I with salt crystals H, as shown.
The general construction and operation of this cell is the same as the following
with relation to Figure 2.
In arranging this device, I make a stiff paste of the coal dust by mixing it with
the above described silicate solution.
Having done this, I place a mass of it in the bottom of the canvas lined
suspended basket C, said mass to be of the. thickness desired for the partition E.
I now construct the anode chamber which consists of the feed tube L and carbon I
and granulated carbon H separately; and set it in the basket on the mass or bed
of paste in the bottom thereof. I may use several carbons instead of a single tube.
To construct said anode chamber I make a cloth bag R of sufficient strength to
support the weight of the anode and feed tube L. I suspend it by the wooden
hoop X and put in. the bottom of it some granulated coke, retorted charcoal, or
retorted anthracite coal F, say two or three inches. I then set in the perforated
feed tube or tile L which in tall tanks may be made of several tiles set end on end.
I then set a carbon conductor or conductors I around the said tile as close as

page_text: convenient, and hold the whole steady while the bag R is filled to the top around
them with granulated conducting carbon F. Having filled the bag and pressed the
carbon down, the carbon I and tubes L will then be held firmly. The bag is then
lifted into the basket C by the ring X which serves no other purpose than to
support and steady it until the whole apparatus is finished, which is then done by
ramming or packing in the annular space E between the lining of the basket and
the anode bag R, the above-described paste, until it is full to the point where the
annular glazed ring O is shown; the said ring is then set in and the space between
it and the anode bag R is filled. After this I cover up the said ring with a
cover J. I then seal up the whole with asphaltum M.
In operation I fill the tank with water or brine as desired through the tube Z and
also fill the feed tube L with the salt crystals to be electrolyzed. I then pour
enough of a preferably saturated solution of brine on the salt which will run
through the perforations and fill up the interstices in the granulated conducting
carbon H. I now connect the carbon I to a source of electricity and complete the
circuit through the partition and tank in such a manner that the acid radicals will
be liberated on the anode and the bases will be liberated at the tank or cathode A.
On pouring the brine into the anode chamber it comes in contact with the inner
surface of the anthracite partition and gelatinizes the silica which it contains and
in time coagulates further in and makes the wall permanent, as silica or anthracite
are not soluble in acids. As canvas is not injured by the bases it makes the outer
or cathode side permanent. The silicates may dissolve out of the surface of the
cathode side but as the anthracite is not soluble the partitions remain impervious
and firm.
When the current of electricity has freed some acid radicals in the anode
chamber they will begin to destroy bag R and in a short time will complete its
destruction, and there would be now nothing left to prevent the substance of the
partition from commingling with that of the anode if the silica was not present.
But the firmness of silicic acid prevents the anthracite particles from moving.
In operating the apparatus, I have found that sulphuric acid is formed, and also
other compounds, such as chlorides aud sulphates of aluminium, iron and calcium,
which are presumably due to the chemical action of the above and other acids upon
such impurities as may be existing in the material used for the diaphragm and the
anode. In some cases it is desirable to remove these during the operation of the
apparatus. When this is desired, I provide a channel connecting with or running
from the anode bag or receptacle, through which such impurities may flow off by
gravity. As shown in Figure 1, Sheet 1, such tube is shown at T, and may be of
any suitable material such as glazed tile, preferably to be closed at the bottom by
a perforated tile W. The tile T may be made tight by means of a stuffing box V
which may be made of iron, if desired, the tightening gland being preferably made
of asbestos wicking.
1
To construct and operate the above described apparatus and to carry out the
process to be described, construct a tank as above and suspend a net of insulated
wire or twine on the ring D. I then put a canvas bag in such net which may be
lined with asbestos paper. I also knead to a stiff dough an amorphous powder
made from anthracite coal, silica, or any substance which will be unacted upon by
either the radical liberated or its base, using a solution of. the base intended to be
transferred for making the dough. For instance, if caustic soda is intended to be
produced a solution of it in water is used. When the dough is made I pack in the
bottom of the bag the amount necessary for the thickness of the partition. I prefer
at least two or three inches of wall although more or less may be used, but the
thicker the wall or diaphragm the purer and richer can the solution of the base be
made. When the thickness desired is attained in the bottom I set in the center
the porous cup or tile F. Then I pack around it, the aforesaid dough until the
space between it and the outer wall filled. I prefer to carry it above the ring D
a little way so as to allow for any shrinkage that might take place.
When this is
done the tubes and anode are sealed in, as described above. When the wax is cool

page_text: '
I fill the space around the anode in the cup or tile through the long tube L, with
the salt crystals and water desired for decomposition, say chloride of sodium or
potash, and pour in enough water to come above the lower end of the wide
tube and seal it; then I fill the outer compartment with water through an inlet Z.
I prefer to use a weak solution of the base on starting to lower the resistance of
the water. I now connect the positive pole of the source of electricity to the anode
and the negative pole to the tank or cathode. The action of the current is to
send the base of any salt, as sodium, potassium, iron or copper, toward the cathode
and liberate the acid radical on the anode. If such radical is a gas it will escape
through the tube K. If it is a liquid it can be drawn off by a syphon or pumped
out when desired. The liquid bases, such as caustic alkalies, may be drawn off at
a cock S. The process can thus be made continuous by adding crystals on the
anode side of the diaphragm and drawing off the base on the cathode side.
The specific form of anode and arrangement of the anode chamber may be much
varied. In Fig. 2, for instance, I have shown a cylindrical anode I, of conducting
charcoal or carbon. The feed tube L extends down through the anode and is
perforated, as shown.
The space around the anode is filled in with coarse particles of a conducting
charcoal or what I have above stated I have found to be the equivalent thereof,
to wit carbonized anthracite coal. In this case the mass of broken charcoal
really constitutes the anode, while the cylinder or rod I serves merely as a
connector.
Heretofore, in apparatus for decomposing salts, crystals of the latter have been
placed around the anode for variously expressed purposes, but no provision has
been made for maintaining a supply of such crystals that will keep around or in
contact with the anede a mass of the same substantially up to or above the
water level, nor, so far as I am aware, has the desirability of any such provision
been recognized.
I find it, however, to be of great importance to do this, in order to prevent
any tendency towards the impoverishment of the solution at any part and the
resultant liberation of oxygen from the water, which is very destructive of the
anode.
In the above apparatus which I have shown and described it has been my
custom to provide diaphragms composed of insoluble substances either in a
gelatinous condition or in such a fine state of subdivision as to render them
impervious to fluids and yet be conductors of electricity, but in the following
case my object is to provide for a diaphragm composed wholly of soluble crystals
of the salt to be decomposed.
In carrying out my invention I employ a vessel of which a three-legged tube is
a general type, that is to say it has three compartments, the central or intermediate
compartment containing a mass of the crystals in a fine state of subdivision and
the end compartment containing the anode and cathode respectively. Electrical
communication between the electrode compartments is maintained through the body
of crystals.
Fig. III, Sheet 11 is a central vertical section of the general form of apparatus
which I use.
Fig. IV, Sheet III is a similar view of a modification of the same.
Fig. V is a top plan and part sectional view of the device shown in Fig. IV.
A designates a tubular receptacle of glass or other like material having three
legs or branches. Into the central branch B, I run in crystals of the salt to be
decomposed and which have been finely pulverized until the said branch is
completely filled. The crystals will form a pile with sloping sides at the lowest
point or bend of the tube and divide the two side branches from each other. I then
partially fill one of the side tubes as C with granulated gas coke retorted anthracite
coal or charcoal D, and force down into the mass a carbon rod or pencil E. The
end of the branch C is then hermetically sealed as by a cover F and a coating of
tar applied around the carbon rod E.

page_text: The other branch G is provided with a similar cover through which a cathode:
of iron or other suitable conductor extends.
At the top of the cathode branch is a tube H for the introduction of the solution,
and in the opposite branch is a gas vent K. Near the bottom of the vessel is a
cock L by which the solution when sufficiently strong in the products of electrolysis
may be drawn.off.
When the apparatus has been thus constructed and arranged the two electrode
branches are nearly filled with a saturated solution of the salt to be decomposed
and the apparatus connected with a source of current. By the action of such
current the acid radicals will be liberated on the particles of the coke or other
substance constituting the anode.
As electrolysis goes on, the salt in solution is gradually decomposed and the
crystals forming the partition are dissolved to take its place. This wearing away
of the partition is at once made good by the descent of fresh crystals from the
tube B which is always kept well filled.
The same results may be secured in other ways. For example, in Figs. IV
and V the vessel or tank is in the form of an ordinary box and may be made of
wood coated with tar or of any other suitable material.
The box is divided into two compartments by a double wall which may be
composed of a jar M of porous earthenware or of glass or stoneware provided with
numerous perforations, or it may be formed by two tiles secured properly in position
It will generally be necessary to provide a luting P of wax or the like, along the
edges and bottom of the jar to prevent leakage around it and to hold it in position.
Between these walls a mass of crystals is constantly maintained to a point above
the level of the liquid in the tank. It is convenient in this device as well as in that
previously described, to provide a hopper or flaring opening for the receptacle
containing the crystals so that a supply of crystals may be always at hand to take
the place of those dissolved off from the partition.
In the case of the apparatus shown in Fig. IV. the compartment on one side of
the diaphragm is filled in with granulated coke or its above described equivalent
surrounding a carbon conductor which is placed as far back from the diaphragm as
practicable. The other compartment contains a cathode as in the previous case,
and the two compartments are closed or sealed in the usual manner, due provision
being made for the escape of gas from the anode compartment and the introduction
of solution on the cathode side. A cock L is employed to draw off the solution
when it has acquired a sufficient strength.
This plan of constructing and operating devices of this character is simple and
economical. In principle of operation it differs in no essential respect from the
forms of apparatus heretofore described and shown by me, but from the fact that
the material composing the diaphragm is in this case soluble, suitable provision
must be made for a constant supply of such material to take the place of that which
is dissolved.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by my
foreign correspondent, I declare that what I claim is :—
1. The improvement herein described in methods of decomposing metallic salts
by electrolysis, which consists in maintaining by continuous feed the supply of crystals
in the anode compartment and in contact with the anode, up to the level of the
solution in said compartment, as set forth.
2. In an electrolytic apparatus, the combination with the cathode tank and anode
of a closed chamber or compartment containing the anode and formed by a partition
composed of or containing a material that renders it substantially non-porous or
impervious to fluids under normal conditions, the anode compartment being
prolonged below the tank in a drain pipe, or passage in which the acids or heavier
impurities may collect by gravity, as set forth.
3. The combination of a cathode tank, and anode supported therein, a mass of

page_text: coal dust around the anode, and a drain pipe or passage from the bottom of the mass
of coal dust for carrying off the impurities resulting from chemical action at the
anode, as set forth.
4. The combination of an iron cathode tank, an anode supported therein, a mass
of granular carbon or the like surrounding the anode, a diaphragm or partition of
pulverized coal confined in a bag and surrounding the granular carbon, and a gravity
drain pipe from the bottom of the mass of granular carbon for carrying off the
impurities therein resulting from chemical action, as set forth.
5. In an apparatus for the electrolysis of metallic salts the combination of a
cathode, an anode and a substantially non-porous or amorphous electrolytic diaphragm
between the same, a cover or seal by which the electrode compartments are closed,
and a feed-tube extending through the cover into an open space in which the
anode is exposed, and opening into said space below the water level, the feed-tube
being of such character as to admit a continuous supply of crystals of the salt
to be decomposed into the open space in the anode compartment, as set forth.
6. In an apparatus for the electrolysis of metallic salts, the combination of a
cathode, and an anode made hollow or with an opening extending through it, an
amorphous electrolytic diaphragm interposed between the cathode and anode, a
cover or seal closing the electrode compartments, a feed-tube extending through the
cover into the space within the anode, and opening into the saine below the water-
line, the feed-tube being of such diameter as to admit a continuous supply of crystals
of the salt to be decomposed into the hollow anode, as set forth.
7. In an apparatus for the decomposition of metallic salts, the combination of a
cathode and an anode, an amorphous electrolytic diaphragmn interposed between the
sume, a mass of broken charcoal between the diaphragm and the anode and in
contact therewith, a feed-tube extending into an open space within the anode, and
adapted to admit to the surface of the anode a continuous supply of the crystals of
the salt to be decomposed as set forth.
8. The combination in an electrolytic cell of an anode consisting of a conducting
body or bodies of carbon surrounded and in contact with a protecting conducting
body of retorted or carbonized anthracite coal, substantially as described.
9. A diaphragm for electrolytic cells composed of an insoluble non-conducting
and non-coherent powder, and a gelatinizable binding material, as set forth.
10. A diaphragm for electrolytic cells composed of an insoluble non-conducting
pulverized substance and a gelatinizable silicate, as set forth.
11. The method or process herein described of producing an electrolytic diaphragm
which consists in forming a paste of an insoluble non-conducting pulverized substance
and a solution of silicate of sola or potash, forming said paste into the desired shape,
providing temporary supports for the same and gelatinizing the solution by
electrolytic action, as set forth.
12. An electrolytic diaphragm composed of powdered anthracite coal and a
gelatinizable silicate, as set forth.
13. In an electrolytic apparatus the combination with the electrodes of a soluble
diaphragm interposed between the same and composed of crystals of the salt to be
decomposed in a finely divided condition, and a means such as a feed tube for
maintaining a supply of crystals to replace those dissolved, as set forth..
14. The combination with a tube or vessel having three branches or legs, of
electrodes in the side branches and a mass of salt crystals in the central branch, as
and for the purpose set forth.
10 11 1004
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.