IM- PROVEMENTS IN TREATING COMPOUND SUBSTANCES BY THE AGENCY OF ELECTRICITY, AND THEREBY DECOMPOSING THEM OR RESOLVING THEM INTO THEIR PROVISIONAL SPECIFICATION
Year: 1872

page_text: LETTERS PATENT to Desmond Gerald FitzGerald, of No. 6, Loughboro'
Road, North Brixton, in the County of Surrey, Electrician, and
Bernard Charles Molloy, of No. 1, Elm Court, Temple, in the
County of Middlesex, Barrister-at-law, for the Invention of "IM-
PROVEMENTS IN TREATING COMPOUND SUBSTANCES BY THE AGENCY OF
ELECTRICITY, AND THEREBY DECOMPOSING THEM OR RESOLVING THEM INTO THEIR
PROVISIONAL SPECIFICATION left by the said Desmond Gerald
FitzGerald and Bernard Charles Molloy at the Office of the Com-
missioners of Patents, with their Petition, on the 6th May 1872.
We, DESMOND GERALD FITZGERALD, of No. 6, Loughboro' Road,
North Brixton, in the County of Surrey, Electrician, and BERNARD
CHARLES MOLLOY, of No. 1, Elm Court, Temple, in the County of
Middlesex, Barrister-at-Law, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN TREATING COMPOUND SUBSTANCES BY THE
AGENCY OF ELECTRICITY, AND THEREBY DECOMPOSING THEM OR RESOLVING THEM

page_text: INTO THEIR COMPONENTS, AND IN APPARATUS EMPLOYED THEREIN,'
follows:-
66
to be as
This Invention has for its object Improvements in Treating
Compound Substances by the Agency of Electricity, and thereby
Decomposing them or Resolving them into their Components, and in
Apparatus employed therein."
In order to utilize on a large scale the chemical effects of the magneto-
electric or the voltaic current we employ carbon electrodes of large
surface.
The carbon electrodes may be formed of several plates or pieces of
carbon in conductive contact, and cemented or otherwise secured to
the sides or to the sides and bottom of the tanks, or the electrodes
may be formed by the deposition of carbon at a high temperature from
ethylene or olefiant gas (bicarburetted hydrogen), or from other com-
pounds rich in carbon upon metallic or other surfaces."
The electrodes, or some portion of them, may be advantageously
saturated with paraffin-wax, or with other substances not readily
susceptible of chemical action, so as to render them impervious to fluid,
more especially where metallic contact is mado with the clectrode, or
again in the case of roughly constructed tanks for electro-metallurgical
and other purposes.
The positive electrode, or both electrodes, may be constituted by
fragments of coke, or of any other suitable form of carbon heaped
together, or kept in position by a framework or diaphragm of suitable
material, these fragments being in conductive contact with each other,
and also with a plate or fragment of carbon connected with a metallic
wire, and saturated internally with paraffin-wax, or other material, as
above mentioned.
The electrodes are connected with a magneto-electric machine driven
by steam power or otherwise, or the tanks may be worked by means of
voltaic or thermo-electric batteries or couples. In some cases they are
divided into two or more portions by means of porous diaphragms.
The tank is to contain a solution of the compound substance to be
decomposed or resolved into its components. Thus, for example, if it bo
desired to liberate chlorine for bleaching fabrics or fibrous materials
from a solution of a chloride, such as common salt, the solution (which

page_text: in this case may be sea water) is placed in the tank, and the tank being
divided by a porous partition, as the salt is decomposed chlorine is
liberated in one of the compartments of the tank, and in the other
caustic soda is produced.
Similarly metallic solutions may be decomposed, and the metals
deposited from them. Such solutions may be formed from metallic ores
by the action upon them of chlorine, or other suitable agent, evolved as
above mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Desmond Gerald FitzGerald and Bernard Charles
Molloy in the Great Seal Patent Office on the 6th November
1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, DESMOND
Gerald FitzGeRALD, of No. 6, Loughboro' Road, North Brixton, in the
County of Surrey, Electrician, and BERNARD CHARLES MOLLOY, of
No. 1, Elm Court, Temple, in the County of Middlesex, Barrister-at-
Law, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of May, in the year of our
Lord One thousand eight hundred and seventy-two, in the thirty-fifth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said Desmond Gerald FitzGerald and Bernard Charles
Molloy, Her special license that we, the said Desmond Gerald FitzGerald
and Bernard Charles Molloy, our executors, administrators, and assigns,
or such others as we, the said Desmond Gerald FitzGerald and
Bernard Charles Molloy, our executors, administrators, and assigns,
should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN TREATING COMPOUND
SUBSTANCES BY THE AGENCY OF ELECTRICITY, AND THEREBY DECOMPOSING THEM
OR RESOLVING THEM INTO THEIR COMPONENTS," 'upon the condition (amongst
others) that we, the said Desmond Gerald FitzGerald and Bernard
Charles Molloy, our exccutors or administrators, by an instrument in
writing under our or their hands and seals, or under the hand and seal

page_text: of one of us or them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the samic was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Desmond Gerald FitzGerald, on
behalf of myself and the said Bernard Charles Molloy, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:
-
This Invention has for its object improvements in treating compound
substances by the agency of electricity, and thereby decomposing them
or resolving them into their components, and in apparatus employed
therein.
In order to utilize, on a large scale, the chemical effects of tho
magneto-electric or the voltaic current, we employ carbon electrodes
of large surface.
The carbon electrodes may be formed of several plates or pieces of
carbon in conductive contact or electrically connected and cemented,
or otherwise secured to the sides or to the sides and bottom of the
tanks, or the electrodes may be formed by the deposition of carbon
at a high temperature from ethylene or olefiant gas (bicarburetted
hydrogen), or from other compounds rich in carbon upon metallic or
other surfaces.
The electrodes are connected with a magneto-electric machine driven
by steam power or otherwise, or the tanks may be worked by means
of valtaic or thermo-electric batteries or couples. In some cases they
are divided into two or more portions by means of porous diaphragms.
The tank is to contain a solution of the compound substance to be
decomposed or resolved into its components. Thus, for example, if it
be desired to liberate chlorine for bleaching fabrics or fibrous materials
from a solution of a chloride, such as common salt, the solution (which
in this case may be sea water) is placed in the tank, and the tank being
divided by a porous partition, as the salt is decomposed chlorine is
liberated in one of the compartments of the tank and in the other caustic
soda is produced.

page_text: Similarly metallic solutions may be decomposed and the metals
deposited from them, such solutions being formed from metallic ores
by the action upon them of chlorine or other suitable agent evolved
as above mentioned.
We take as one example of the application of our processes, tho
decomposition of sodic chloride (common salt) in solution; first, in
such manner as to obtain separately a solution of chlorine and a
solution of sodic hydrate (caustic soda); and secondly, in such manner
as to obtain a solution containing sodic hypochlorite. In the former
case we place the solution of salt in a tank furnished with carbon
electrodes of large surface, which tank is divided into two or more
compartments by means of porous diaphragms, the two terminal
compartments containing respectively the positive and the negative
electrodes.
The tank may be constructed of brick cemented with plaster of
Paris or otherwise, slate, siliceous stone, stoneware, or other suitable
material not readily acted upon by the products of the decomposition.
In order to construct electrodes of large surface with the com-
paratively small plates or pieces of "gas carbon," graphite coke, or
"moulded carbon" (herein-after generally referred to as "carbon"),
which are commercially obtainable, we attach by means of cement
a number of such plates or pieces to the inside of the tank so as to
cover the required extent of surface in the terminal partitions, taking
care that these plates or pieces are in good conductive contact at their
edges. In order further to ensure such contact the carbon plates may
be pierced with holes along their edges, and connected together by
means of “pegs" or short cylinders of carbon fitting into the holes ;
or without employing any cement the carbon electrodes may be built
up with "bricks" or lumps of carbon in conductive contact, which may
be connected together, as above mentioned.
In order to bring the electrode into perfect conductive connection
with one of the poles of a magneto-electric machine or other source
of electricity, a plate or piece of carbon may be partially or wholly
saturated with paraffin-wax, collodion, or any other substance not
readily attacked by the products of the electro-chemical action in
any particular case, which substance is subsequently removed from
the surface of the carbon so as to allow of conductivo contact with
this surface, whilst the carbon is rendered impervious to fluid. The

page_text: lower portion of this plate or piece of carbon is built into the electrode
so as to be in perfect conductive contact with it, whilst the upper
portion projects above the fluid contained in the tank, allowing of a
suitable attachment for the wire conveying the electric current.
The means of attachment we prefer at the anode or positive electrode
is a binding screw having a large surface of platinum in contact with
the carbon. Another means is to pierce a hole in the carbon, into which
is tightly inserted a thick platinum wire, rivetted to the carbon with
platinum rivets, and insulated from the fluid in the tank. In either
case no strain should be brought to bear upon the binding screw or 1
platinum wire, which should be connected to a binding screw fixed to
the tank.
-
We do not invariably cause a portion of the electrode to project above
the fluid in the tank, as in certain cases we prefer to make the con-
nection through the side of the tank by means of a platinum wire, as ]
aforesaid.
The cathode or negative electrode need not in all cases, nor in the
particular instance here referred to, be constructed of carbon, but may
be formed of a plate of metal, such as tinned iron.
The porous diaphragm or diaphragms may be formed of plates of
unglazed earthenware, supported in vertical grooves in the sides of the
tank, and also in pillars or uprights fixed at intervals in the bottom of
the tank; or the plates may be supported by grooved or double cross
picces extending across the tank or held in a framework of some suitablo
material.
The pillars or cross pieces supporting the plates of unglazed carthen-
ware (closely fitted or cemented together at their edges) may be of slate,
glass, or other material not readily acted upon by chlorine or caustic
alkali.
It is preferred to construct two diaphragms in tolerably close juxta-
position, as by this means the effective separation of the two portions of
fluid contained in the terminal compartments is secured with greater
certainty.
The diaphragm or diaphragms may if preferred be constructed of
plaster of Paris, "vegetable parchment," or any other porous or pervious
191

page_text: The tank should have a cover air-tight or nearly so, and provided with
a tube or tubes through which the bydrogen gas evolved, and also any
chlorine which may escape solution, may be conveyed away, the surplus
chlorine to be absorbed by caustic lime or otherwise, and the hydrogen
to be utilized for any desired purpose or to be allowed to escape into the
air. When a tank so constructed is charged with a cold saturated or
dilute solution of common salt, or with sea water, and when the elec-
trodes are respectively connected with a source of electricity, such as a
magneto-electric machine worked by steam, air, or water power, the
solution of salt is decomposed, and one of its constituents, chlorine, is
obtained in solution in the compartment containing the positive electrode,
whilst caustic soda is obtained in that containing the negative electrode.
The apparatus may be advantageously used by bleachers and paper
manufacturers, and others to whom both solutions are of value.
The two solutions may be mixed together, in which case they form a
solution of chloride containing sodic hypochlorite.
If the tank be charged with a strong solution of potassic or sodic
nitrate, potassic or hydropotassic sulphate, or sodic sulphate, the acids
will respectively accumulate in the positive compartment, whilst the
alkalies will be obtained in the negative compartment, the reactions
taking place being expressed in the following equations:-
KNO, + H,O= KHO + HNO₂, or Na NO, + H2O = Na HO +
HNO,; K, SO, + 2(HO) = 2(KHO) + H₂SO.; KHSO + H₂O=
KHO+H, SO, and Na, SO. + 2(H₂O) = 2.(Na HO) + H, SO.
The alkaline and acid solutions may be concentrated and the products
obtained in a condition of greater or less purity by means which are well
understood. Thus for instance, a solution containing potassic hydrate
may be evaporated to dryness and the potassic hydrate dissolved out by
means of alcohol; and a solution containing sulphuric acid in admixture
with hydropotassic sulphate may be concentrated by evaporation, and
the acid then obtained by distillation.
In the second case above specified, that in which sodic hypochlorite is
directly obtained, the solution of common salt is placed in a tank con-
taining a number of plates of carbon in close juxtaposition, and alter-
nately connected to the positive and negative poles of the source of
electricity. The comparatively small plates of carbon are thus made to
constitute two electrodes of any required extent of surface.

page_text: The tank may be constructed of any of the materials specified in the
former case, and the carbon plates may be secured to the sides, the
bottom, or the top of the tank in such manner as to occupy nearly the
whole of its interior, with the exception of the spaces between the plates
to be occupied by the fluid submitted to the action of the electric current.
We prefer to arrange the plates at a distance of about one inch apart,
and to secure them by passing them through apertures in the lid or
cover of the tank, the portions thus passing through the apertures being
saturated with paraffin-wax, collodion, or other substance not readily
attacked by the products of the electro-chemical action, and afterwards
brought into conductive contact with a binding screw or wire. The
hydrogen evolved may be conveyed away as in the former case. By the
abstraction of this hydrogen the sodic chloride solution becomes partially
converted into one of sodic hypochlorite, thus, Na Cl + H, O-2H=
Na Cl O, this sodic hypochlorite in conjunction with sodic chloride being
what is known as chloride of soda (Na, O C₁₂ = Na Cl + Na Cl O).
The reaction cannot economically be carried beyond a certain point,
and for this reason it is preferred generally to arrest the decomposition
when about 25 per cent. of the salt has been converted into chloride of
soda (or 12.5 per cent. into sodic hypochlorite) in the case of saturated
or nearly saturated solutions; or when 50 per cent. of the salt has been
converted into chloride of soda (or 25 per cent. into sodic hypochlorite)
in the case of a half saturated solution. By this means we obtain a
solution containing about 2 per cent. of available chlorine, which solution
we find to be of the proper strength for most bleaching operations.
The solution may be returned to the decomposition tank after it has
been used for the purpose of bleaching, since in this operation sodic
chloride is regenerated, Na, Cl. O becoming 2(Na Cl) by evolution of
oxygen.
3
If a hot and concentrated solution of sodic or of potassic chloride be 3
submitted to electrolysis, as above, the sodic or the potassic chlorate
(Na Cl O, or KClO) is obtained, and may be separated by crystal-
lization. The conversion in this case is facilitated by exposing the
solution to the direct rays of the sun; for this purpose the cover of the
tank may be glazed.
In some cases we construct carbon electrodes by depositing carbon at
a high temperature from ethylene or olefiant gas (bicarburetted hydrogen)
or from other compounds rich in carbon upon metallic or other surfaces.

page_text: wwwww
Plates of iron or of unglazed earthenware, for instance, may be heated
to bright redness in a close casing through which is passed a stream of
coal gas prepared at the lowest practicable temperature. The plates will
become coated with a layer of carbon, which in the case of a metal may
be saturated internally with paraffin-wax or other substances not readily
susceptible of chemical action, but which will render a coating of
carbon impervious to fluid. The paraffin-wax or other substance should
be carefully removed from the surface of the carbon.
If a solution of calcic chloride (a waste product of the ordinary process
of manufacturing sodic carbonate) (soda) be substituted for the solution
of sodic chloride with which the tank is charged, as above, a solution
of chloride of lime (Ca O O₁₂) is. obtained instead of that of chloride
of soda.
When hydric chloride (muriatic or hydrochloric acid) is electrolysed,
bydrogen is evolved at the negative electrode, whilst at the positive
electrode chlorine is liberated, and may be obtained in solution. The
solution of chlorine acts upon nearly all the metals, dissolving those of
which the chlorides are soluble; it will also separate them in many
cases from those combinations which constitute their ores. Thus, if a
quantity of auriferous quartz, Australian copper ore (consisting chiefly of
the
green and blue carbonate in a siliceous matrix), or copper glance, or
grey antimony ore, for instance, be placed beneath the electrodes at the
bottom of the tank last described, or in the positive compartment of the
tank previously described, and if hydric chloride be then made the
electrolyte, the chlorine evolved will react upon the ores, and dissolve out
the metal which will subsequently be deposited in a reguline state at the
negative electrode, provided in the latter case the metallic solution bo
transferred from the positive to the negative compartment, giving place
to a fresh charge of ore and of hydric chloride. Or, if sodic chlorido be
made the electrolyte in the tank divided into compartments by a porous
diaphragm, then a metallic solution may be obtained from the orc in the
positive compartment, whilst a solution of sodic hydrate is obtained in
the negative compartment. Upon mixing the two solutions the metal
will be precipitated as oxide, whilst sodic chloride is regenerated.
In the case of a sulphide the sulphur will be left as a residue at the
bottom of the tank, together with the matrix gangue or other impurity.
Sodic or potassic nitrate may be employed in lieu of sodic chloride, as

page_text: last described, in which case nitric acid will be evolved at the positive
clectrode.
In adopting the means here indicated for the extraction of metals
from their ores, we prefer generally to use a tank similar to that first
described, but without a diaphragm, and having a positive electrode of
carbon extending not only over the inner surface of one side of the tank,
but also over a considerable portion of the bottom, so that the ore may
rest upon this part of the electrode, and thus be readily acted upon by
the evolved chlorine.
In treating the ores of copper we prefer to use a negative electrode of
copper. In most cases we prefer to use hydric chloride (muriatic acid)
as the electrolyte.
In order to avoid the expence of cutting and working gas carbon
(which we find to be the best form of carbon for the construction of
electrodes), and for the purpose of utilizing rough fragments of gas:
carbon, graphite, or coke in the construction of the tanks we use for
treating saline solutions and for obtaining metals from their ores by the
agency of electricity we adopt various methods, of which the following
may be taken as examples :-
I. For clectro-metallurgical and other purposes a decomposition tank :
may be roughly constructed as follows:-A space the required size of
the tank may be excavated in the earth, and lined with brick, siliceous
stone, slate, or any other material which will resist the action of the
products of the electro-chemical decomposition to be effected, or the
tank may be built above the surface of the earth as usual. A partition :
which may be only a few inches high divides the tank into what may
be termed the positive and negative compartments; this position, which
is for the purpose of preventing any accidental contact between the
electrodes, may be of the same material as the tank.
Two rough
fragments of (preferably) gas carbon of considerable length have one 3
extremity cut so as to take a binding screw having a platinum surface
of a least two square inches, to be applied in contact with the carbon, or
this extremity is fitted with a thick platinum wire, as herein-before
described. These fragments are respectively placed in the middle of
the two sides or extremities of the tank which are to be occupied by 3
the electrodes, and are surrounded with a heap of fragments of gas
carbon or of coke closely packed, so as to make contact with cach
other and with the above-mentioned carbon nucleus to which the poles

page_text: of the electrical source are to be connected. The fragments in the
positive compartment may extend to the partition across the middle of
the tank in the negative compartment; it is best not to allow these
fragments to extend so far as the partition.
The charge of ore is made to rest upon the carbon in the positive
compartment, the residues, gangue, &c., being allowed to accumulate
until the tank is cleared. The carbon electrode in the negative com-
partment may be replaced by a plate of metal, in which case the latter
should be removed from the tank so soon as the current ceases to pass,
in order to avoid the action upon it of the chlorine or acid solution.
When the negative element is of coke, the reduced metal is allowed to
accumulate upon it, and the coke is subsequently made to aid in the
fusion of this metal.
II. For the manufacture of hypochlorite solutions, chlorates, &c., and
also for the decomposition of salts into acid and alkaline educts, tho'
clectrodes may be constructed as follows:-The tank is divided into a
number of compartments by means of vertical partitions, which may
be formed of plates of unglazed earthenware pierced with holes, which
plates are secured in vertical grooves made in the sides of the tank, and
in uprights fastened to the bottom and extending across it. The
terminal comparments and each alternate compartment (which may be
of different capacity to the remaining compartments) are filled with
fragments of gas carbon, graphite, or coke. The compartments so filled
constitute the electrodes which are alternately connected to the positive
and negative poles of the source of electricity, by means of fragments
of carbon of considerable length fitted with a binding screw or platinum
wire, and embedded amidst the remaining fragments as herein-before
described. The compartments intervening between the electrodes aro
filled with the solution to be decomposed or treated by the agency of
electricity.
In certain cases the holes or perforations in the plates of unglazed
earthenware or other material of which the partitions are formed (which
boles or perforations are for the purpose of allowing free circulation of
the fluid) are dispensed with in the case either of the positive or the
3 negative compartments, or of both, and a plate of metal may be
substituted either for the negative or the positive electrode of carbon.
Or each compartment instead of every alternate compartment may
contain an electrode, such clectrodes being alternately connected to the

page_text: positive and negative poles of the source of electricity. The plates of
unglazed carthenware forming the partitions may when necessary be
cemented together and into the grooves by which they are held in
position for the purpose of obviating the free circulation of the fluid.
The tank may be fitted with an air-tight cover furnished with a tube or
tubes for carrying away the liberated gases, and it may also be fitted
with taps or other appliances for running off separately the fluids
contained in the positive and in the negativo compartments.
III. The layers of carbon fragments constituting the electrodes may
be arranged horizontally, in which case we prefer to place the positive
electrode at the bottom of the tank in connection with a piece of carbon
or a wire attached to a fragment of carbon passing through the side of
the tank, the fragments constituting the negative electrode (from which
hydrogen gas is in most cases evolved) are supported at any required
distance from the positive electrode by means of a false bottom formed
of slabs or plates of unglazed earthenware, which may be pierced with
holes. The connection with the negative electrode is made as herein-
before described. A horizontal diaphragm formed of plates of unglazed
earthenware may extend about midway between the two electrodes, thus
dividing the tank into two compartments from which the acid and
alkaline educts respectively liberated at the positive and negative
electrodos may be obtained separately.
In order to purify sulphuric acid from the sulphate of lead with which
the commercial acid is generally contaminated, and to remove metallic
impurities from other fluids, we pass the acid or other fluid between
electrodes of carbon arranged in a tank as follows:-Calling two opposite
sides of the tank P and N, a plate of carbon is secured vertically to the
side N at a short distance from one of the remaining sides or ends of the
tank, which plate extends nearly to the side P, and is also secured to or
in contact with the bottom of the tank. A second plate of carbon is
similarly secured to the side P of the tank at a short distance from the
first plate, and extends nearly to the side N, being secured as before to
the bottom of the tank. Other plates are alternately connected to the
sides N and P, the last plate being at a short distance from the second
remaining side or end of the tank. The plates attached to the side N
of the tank are connected to the negativo pole of a source of electricity,
and those attached to the side 1', to the positive pole of the source. The
acid or other fluid is admitted at one end of the tank, and is made to

page_text: DESMOND G. FITZGERALD. (L.S.)