Improvements in or relating to Electrolytic or Galvanic Processes or Cells.
Year: 1895

page_text: Date of Application, 23rd Sept., 1895
Complete Specification Left, 20th June, 1896-Accepted, 23rd Sept., 1896
[Communicated from abroad by CARL HOEPFNER, of 36 Frankfurterstrasse,
Giessen, in the Empire of Germany, Doctor of Philosophy.]
Improvements in or relating to Electrolytic or Galvanic Processes
or Cells.
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 to be as follows:-
For the purpose of carrying out electrolytic decompositions in as rational and
economical a manner as possible, i.e., with the least possible electromotive force,
especially such decompositions in which it is desired to bring about reactions at
the cathode only (for example, where zinc or other metals, such as iron, nickel or
copper are to be obtained from their salts by the electrolytic process at a moderate
cost) propose to employ a bath which, for ordinary cases, should be divided by
suitable membranes or diaphragms into anode and cathode cells, in such a manner
that anode cells communicate with anode cells, and cathode cells with cathode
cells (say, in the manner described in the Specification of British Letters Patent
No. 13735 of 1890).
The cathods cells are then filled with the liquid to be decomposed, for example,
the solution of the metallic salt to be decomposed, such as chloride of zinc, bromide
of zinc, sulphate of zinc, nitrate of zinc or acetate of zinc, or an alkaline solution
of oxide of zinc (or similar solutions of other metals)-wbile the cathodes will
consist of carbon or any suitable metal in the shape of plates, discs, rods, or
hollow bodies capable of being heated from within.
It will be found very advantageous to actively maintain the cathode solution or
lye, at the cathodes in constant motion, so that the cathodes, are kept revolving or
vibrating; and it is also necessary that the lye should be sufficiently concentrated
and kept warm by being made to circulate from an appropriate reservoir, through
the cell, in a suitable manner.
The anodes I employ for the purpose of reducing the electro motive force
required for decomposition to a minimum (in fact, for making it actually negative,
in the case of copper salts, for example) are not insoluble, but are soluble anodes,
consisting of metals, or metalloid substances, while I take care, at the same time,
that the solutions obtained therefrom do not reach the cathodes, but are preci-
pitated from the anode lye in a harmless manner, before they become too rich or
abundant.
The metals dissolved from the anodes are, in fact, made insoluble either chemically
or physically (or in other words in any convenient manner) and the resulting
precipitates, which may be obtained within, but should be preferably produced
outside, the anode cell, are collected and utilized again for any useful purpose.
As a rule, they should be regenerated, i.e., restored to the metallic state by means
of carbon or other reducing substance, such as hydrogen.
The anodes therefore should preferably consist of lead or materials containing
lead such as sulphuret of lead or argentiferous lead.
These materials may be employed in the form of solid bars or plates, or
(especially in the case of sulphides) in a granulated or powdered condition. In

page_text: the latter case the electric current may be admitted through electro-negative metals,
such as copper or silver wire-netting or carbon rods or the like, which should be
retained in close contact with the pulverulent metals or sulphides. As to the
anodes, it is also better to keep them in motion, so as to facilitate the formation of
a uniform solution, and the employment of powdered sulphides.
The anodes are surrounded by an acid or a salt solution which should preferably
be heated, and the nature of which should be such that it will dissolve the
compounds of lead, formed electrolytically at the anode. The agents most suitable
for the attainment of this object are solutions of chlorides, such as common salt,
chloride of calcium, chloride of zinc, chloride of potassium, or the like; or nitrates,
such as nitrate of sodium, nitrate of zinc; or acetates, such as acetate of sodium, or
acetate of zinc; or acids or salts capable of forming soluble compounds with lead.
The lye or solution should circulate, in a suitable manner, past the anodes and
should dissolve the lead salt (chloride of lead, when chloride of zinc is present)
as it forms.
In order to enable this process to be kept up in a regular manner for a com-
paratively extended period of time, care should be taken to prevent the anode
Iye from absorbing too large an amount of lead;-in no case more than from about 50
to 100 grammes per litre, for if the quantity were larger, this would cause the
voltage necessary for the decomposition to rise unduly; besides, the lead, or,
instead of lead, other metals which are used as, and dissolved from the anode,―
would be readily diffused towards the cathode and thereby impair the purity of the
zinc.
The lye, therefore, constantly circulates past the anodes, and is freed, in the
course of this process, within, or,-which is still better, outside the bath, from the
whole or part of the lead (or other metal) which it contains.
For the purpose of this precipitation of the lead from the anode lye, any
chemical precipitant may be used which is capable of precipitating lead from its
solutions without introducing other injurious matters into the solution instead of
such lead.
In obtaining zinc by this electrolytic process, the following chemical agents
will be found best suited for precipitating the lead:
Sulphate of zinc
Chromate of zinc
Sulphite of zinc
Carbonate of zinc
-
ZnSO₁
ZnCrO4
ZnSO,
-
ZnCOs
ZnSiO,
-
ZnO
Sulphide (or sulphuret) of zinc
Chloride of zinc
-
ZnS
ZnCl,
Silicate of zinc
Oxide of zinc
-
By means of any of these agents, lead may be precipitated from solutions of
chloride, nitrate or acetate, in a very rational manner, and at the same time (by
alternate decomposition) the lye will again be enriched with zinc, the reaction
being as follows:
ZnR + Pb(NO3), PbR + Zn(NO₁),.
insoluble.

page_text: r substances containing oxide of lead, which will form a nearly insoluble basic
alt, when brought into contact with the salt of lead contained in the anode lye.
In some cases, i.e., where an inexpensive source of heat is available,-the
lissolved salt of lead may be precipitated simply by a physical process, viz. by
In order to
cooling, by diluting the solution or by the addition of an acid.
eliably prevent a diffusion of lead from the anodes to the cathodes, sulphates or
other substances capable of rendering the salts of lead insoluble, may be dissolved
n the cathode lye.
The lead compounds, such as sulphate of lead, chloride of lead, oxide of lead,
or sulphide of lead, precipitated in the manner herein before described and which
may vary extensively in their nature, may be utilized in any convenient manner in
the manufacture of peroxide, colours (or dyes), glass, and other substances. It is
essential, however, to note (a fact generally known already) that these compounds
may be, at a very small cost indeed, restored to the metallic state by carbon,
hydrogen, water gas or other reducing mediums, such as natural sulphides, (galena
or iron pyrites for example) and may then be employed over again, in the constant
circulation process, as anodes.
Supposing it is desired to reduce to the metallic state from its oxide 206 kilo-
grammes of lead 12 kilogrammes of carbon will suffice to effect the reduction.
Similarly chloride of lead (and also chloride of copper) may be reduced to the
metallic state by means of hydrogen, hydrochloric acid being formed at the same
time, as also chlorine if air be suitably admitted.
This hydrochloric acid and chlorine as well as sulphurous or sulphuric-acid
obtainable from the decomposition of sulphate of lead can be used over and over
again for dissolving metallic oxides or sulphides and for regenerating the original
solutions.
In a similar manner it is possible to make use of the described lead-anodes
process for obtaining also other metals by this electrolytic process,-such, for
example, as nickel, iron, munganese, chromium, aluminium, and even alkaline metals
or alloys or amalgams of the same, which are more electro-positive than lead. On
the other hand, this process is also available for the production of metals
which are more electro-negative, for example, silver, copper, bismuth, antimony,
mercury or the like, all of which may be obtained from their corresponding
solutions.
It will naturally be likewise endeavoured to displace the lead in solution (as is
the case with zinc in the operations above described) by means of compounds of
the metal to be obtained, and more particularly by means of sulphates, chlorides
and oxides, and thereby, at the same time to maintain a uniform concentration of
the lye.
In all these cases, the lead will constitute an excellent energy-saving or volt-
saving anode, capable of reducing the electromotive force at the pole by nearly
two volts and enabling its salts to be very readily and reliably separated again,
while at the same time,-being readily fusible, it permits the metal to be
regenerated in a very economical manner, and renders the employment of com-
plicated filtering machines, in the precipitating process, unnecessary, inasmuch as
the metal is heavy and readily settles as it is precipitated.
Lastly, the silver contained in argentiferous lead (silver lead bullion) if such be
used for the anode can be readily and completely extracted, since it remains
undissolved while the lead is being dissolved.
Similarly to lead, mercury,-though it is more expensive,―may be utilized as an-
anode, inasmuch as it is still more readily recoverable as a metal, from its
compounds, than lead is. The same applies to bismuth, tin, antimony, or alloys
thereof.
But although lead appears to be the best and most economical material for
forming anodes which permit a considerable amount of electric energy to be saved
and are at the same time capable of being readily regenerated, yet, in some cases,-
especially where it is desirable that the anode should be of small specific weight,

page_text: and where other raw materials, such, for example, as iron pyrites, are available at
a moderate cost, other substances may be employed as substitutes for lead.
Among these may be instanced (as before mentioned) nickel, copper, or the like.
In that case also, however, it is absolutely necessary to prevent the anode solution
from becoming too richly impregnated with the metal dissolved therein.
This anode solution, which, where the anodes are lead, must not, of course,
be a solution of sulphate, may, in the cases just mentioned (i.e., where copper, or
nickel is used), be a sulphate solution without any inconvenience, since these metals
are not insoluble as sulphates. But in this case also, the anode solution should not.
absorb more than from 50 to 75 grammes per litre of the dissolved metal. Here
also, therefore, the operation should be so conducted that the dissolved metals may
be precipitated or displaced by materials which are harmless,-more particularly
compounds of such metals as shall be obtained electrolytically.
Iron solutions obtained in this manner at the anode, are (for the production of
zinc) best decomposed by oxide of zinc,-after having been first completely
converted into solutions of salts of oxides, and similarly, solutions of tin salts
and of sulphate of copper, which respectively form at the anodes, are in this
case treated with oxide of zinc, so that tin and copper may be displaced by
zinc.
Tin if used for an anode is in all cases readily separable from the solution in
the condition of the oxide or sulphide, and copper may be again separated in the
well-known manner from a sulphate or cupric solution, in the condition of cuprous
chloride, oxy-chloride, oxide, prot-oxide or sulphide.
In fact all the well known methods of precipitating metals may be employed,
provided they are capable of removing the metal dissolved at the anodes in a
harmless manner.
In many cases it will be sufficient to obtain a precipitate simply by the employ-
ment of lime or magnesia, and the salts thus obtained, such as chloride of calcium,
may then be very readily utilised again in the production of chloride of zinc from
oxide of zinc or carbonate of zinc.
It has been stated above that by proceeding in the manuer described i.e. by using
energy saving anodes, especially anodes inade of lead, alkaline metals (as well as
the other metals previously mentioned) or, if desired, amalgams or alloys of the
same, may be produced in an economical manner. It is therefore obvious that, by
this process or, if required, with the additional employment of the known & so-called
quicksilver membranes, caustic alkalies and hydrogen may be obtained instead of
alkaline metals by allowing water to act upon the alkaline metals in the nascent
state. The same applies to caustic baryta and caustic strontium as well as to
other hydrates of metallic oxides.
By this method, then, with the use of soluble anodes, the sulphates of potassium,
ammonium and even of sodium, which, latter sulphate as is well known is very
cheap and almost worthless, may be profitably decomposed. In the course of this
operation, the sulphuric acid becomes fixed or bound on to the lead; practically
the lead is first dissolved from the anode as a nitrate, chloride or acetate, and then
precipitated by the sulphate of sodium, and is then by any known smelting process
separated from the sulphate of lead again in the metallic state, whereby the
sulphuric acid is recovered in the condition of sulphurous acid, while at the same
time, at the cathode, caustic alkalies are produced. The electrolytic decomposition
of the sulphates here takes place indirectly; soluble compounds of lead being first
produced at the anodes, and subsequently decomposed or disintegrated by
duplex" decomposition through the action of the sulphates in question, as
follows:-
:-
66

page_text: converted into their corresponding salts by admitting into their presence certain
acids, such as carbonic acid, phosphoric acid, boracic acid, oleic acid, or the like.
Metal, such as zinc or nickel, may be obtained simultaneously with caustic
alkalies, when the corresponding metallic oxides are dissolved or suspended in the
alkaline solution of the cathode; the oxides used being for instance the oxides of
zinc, or lead.
Sulphides or sulphurets of alkalies will likewise form at the same time with
metals if metallic sulphides or sulphurets, such as sulphide of antimony, sulphide
of lead, or iron pyrites, be in solution or suspension in the alkaline solution of the
movable cathode.
Where there is only an acid at the cathodes, such for example, as hydrochloric
acid or sulphuric acid, in the absence of a metallic salt, the only product of the
electrolysis is the gaseous hydrogen. This is obtained with so small a voltage,
that this method of producing hydrogen may be described as the cheapest method
conceivable owing to the fact that the lead anodes can be so economically
regenerated.
Organic substances also such as "nitro" bodies, may be treated by the reducing
process at the cathodes by the aid of this system of energy saving anodes.
This principle of construction of energy saving anodes may be applied also to
the treatment by electrolysis of melted salts. In such case the lead anode is
melted and lies at the bottom of the melting chamber or vessel; over it, the
cathode is placed, which should preferably consist of tubes capable of being heated
internally; and between the anode and the cathode is interposed the flux,-such as
common salt nixed with chloride of potassium or other salts which lower the
melting point.
Chloride of lead will then form at the anode, and upon sulphates, such as
sulphate of soda (Glauber's salt) or gypsum, being admitted to it, this chloride of
lead will decompose into sulphate of lead; or if brought into contact with lime, it
will decompose into oxide of lead; and the oxide of lead compounds, thus formed,
are reduced, either outside, or (preferably) inside, the bath, by means of an
admixture of powdered charcoal. Hence, carbon monoxide or dioxide will escape,
leaving behind lead in the regenerated metallic state.
It
The employment of energy saving anodes of lead or other easily fusible and
reducible metals, such as bismuth, enables convenient electrolytic baths to be
readily constructed and made to operate with a very low electromotive force.
has already been stated above that energy saving anodes especially if the latter
be lead in some cases are capable of yielding a surplus of energy (like galvanic
cells).
This applies more especially to those instances where the electromotive force
required for the decomposition of certain fluids is less than the electromotive force
set up by the act of dissolving the lead,-which amounts to about 1.8 volts. Such
is the case for example, where the salts of copper or silver, or solutions of nitrates
are decomposed by the aid of lead anodes.
Hence it follows that these energy saving anodes, especially lead and such
other metals, as nickel, which are insoluble in diluted sulphuric acid or hydro-
chloric acid, but may be readily reduced from their oxides, salts and chlorides, by
means of carbon, hydrogen, or other reducing agents, may very advantageously
be utilised as anodes in galvanic batteries, as substitutes for zinc. And such anodes
may, of course, be also made use of in the manner above described in constructing
economical batteries with zinc anodes for the purpose of reducing the zinc from
its metallic solutions or compounds, such as sulphate of zinc for example, at a
moderate cost.
The aim to which the process herein described mainly tends is to enable carbon
to be indirectly used in making anodes, or in other words to take advantage of the
chemical energy inherent in carbon, in carrying out electrolytical operations, by
using anodes which are readily and economically reducible to the metallic state by
the action of carbon, or water gas.

page_text: The dynamic production of electricity has only, hitherto, utilised about
ten per cent. of the energy inherent in carbon; whereas the present process
enables a far greater proportion of the energy thus generated to be satisfactorily
turned to account. Two-thirds to three-fourths of the clectromotive force
necessary for chemical decompositions can henceforward be supplied by direct
transformation of chemical into electrical energy.
Carbon for itself when directly transformed by electrolysis into carbon oxide is
not capable of furnishing more than 75 volts, whereas by the hereindescribed
system it furnishes indirectly about 2 volts.
Carbon moreover has the drawback of being a bad conductor of electricity
whereas its "substitute and offspring" the lead is a good one.
Lastly, conforming to this process, besides carbon, other sources of energy,
hitherto, completely neglected, such as pyrites or galena can be utilized.
Dated this 23rd day of September 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in or relating to Electrolytic or Galvanic Processes
or Cells.
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 :-
For the purpose of carrying out electrolytic decompositions in as rational and
economical a manner as possible, i.e., with the least possible electromotive force,
especially such decompositions in which it is desired to bring about reactions at the
cathode only (for example where zinc or other metals, such as iron, nickel or copper
are to be obtained from their salts by the electrolytic process at a moderate cost)
I propose to employ a bath which, for ordinary cases, should be divided by suitable
membranes or diaphragms into anode and cathode cells, for instance in such a
manner that anode cells communicate with anode cells, and cathode cells with
cathode cells (say, in the manner described in the Specification of British Letters
Patent No. 13735 of 1890) or a bath in which the cathode cell is placed above the
anode cell.
The cathode cells are then filled with the liquid to be decomposed, for example,
the solution of the metallic salt to be decomposed, such as chloride of zinc, bromide
of zinc, sulphate of zinc, nitrate of zinc or acetate of zinc, or an alkaline solution of
oxide of zinc (or similar solutions of other metals) while the cathodes will consist
of carbon or any suitable metal in the shape of plates, discs, rods, or hollow bodies
capable of being heated from within.
It will be found very advantageous to actively maintain the cathode solution or
lye, at the cathodes in constant motion, so that the cathodes are kept revolving or
vibrating; and it is also necessary that the lye should be sufficiently concentrated
and kept warm and be made to circulate, from an appropriate reservoir, through
the cell, in a suitable manner.
The anodes employ for the purpose of reducing the electromotive force required
for decomposition to a minimum (in fact for making it actually negative, in the
case of copper salts, for example) are not insoluble, but are soluble anodes
consisting of metals, or metalloid substances, while 1 take care, at the same time,

page_text: that the solutions obtained therefrom do not reach the cathodes, but are pre-
cipitated from the anode lye in a harmless manner, before they become too rich or
abundant.
The metals dissolved from the anodes are, in fact, made insoluble either
chemically or physically (or in other words in any convenient manner) and the
resulting precipitates, which may be obtained within but should be preferably
produced outside, the anode cell, ,-are collected and utilized again for any useful
purpose. As a rule, they should be regenerated, i.e., restored to the metallic state
by means of coal or other reducing substance, such as hydrogen or water gas or by
organic substances as wood or coal.
The metal of the soluble anodes differs from the metal of the final product to be
obtained at the cathode and is readily precipitable from its solutions like lead, but
is insoluble in diluted acid (especially in diluted sulphuric acid) so as to exclude for
instance zinc and iron from the employment for the anodes; such anodes therefore.
may preferably consist of lead or materials containing lead such as sulphuret of
lead or argentiferous lead.
These materials may be employed in the form of solid bars or plates, or
(especially in the case of sulphides) in a granulated or powdered condition. In
the latter case the electric current may be admitted through electro-negative
metals, such as gun metal or copper bronze or silver wire-netting or carbon rods or
the like, which should be retained in close contact with the pulverulent metals or
sulphides. As to the anodes, it is also better to keep them in motion, so as to
facilitate the formation of a uniform solution, and the employment of powdered
sulphides which otherwise might loose the contact.
The anodes are surrounded by an acid or a salt solution which should preferably
be heated, and the nature of which should be such that it will readily dissolve the
compounds of lead, formed electrolytically at the anode. The agents most suitable
for the attainment of this object are solutions of chlorides, such as common salt,
chloride of calcium, chloride of zinc, chloride of potassium, or the like; or more
conveniently nitrates, or nitrites such as nitrate of sodium, nitrate of zinc; or
acetates such as acetate of sodium or acetate of zinc; or acids or salts capable of
forming soluble compounds with lead.
The hereinbefore mentioned heating of the anode liquid (the cathode liquid may
also be heated in a like manner) can be performed in any suitable or known.
manner of heating; e.g. such heating inay be performed by keeping the liquids or
lyes in circulation and heating the same outside of the battery or cells in any
suitable vessel or the like by any known heating means or the said liquids may be
Heated within the battery or cells by means of heating contact bodies or coils.
arranged therein.
The lye or solution should circulate, in a suitable manner, past the anodes and
should dissolve the lead salt (acetate of lead, when acetate of zinc is present) as-
it forms.
In order to enable this process to be kept up in a regular manner for a.
comparatively extended period of time, care must be taken to prevent the anode
lye from absorbing too large an amount of lead,-in no case more than from about
50 to 100 grammes per litre, for if the quantity were larger it would cause the
voltage necessary for the decomposition to rise unduly, besides, the lead, or,
instead of lead, other metals which are used for and dissolved from the anode,
would be readily diffused towards the cathode and thereby impair the purity of the
zine.
The lye, therefore, constantly circulates past the anodes, and is freed, in the.
course of this process, within, or,-which is still better,-outside the bath, from.
the whole or part of the lead (or other metal) which it contains.
For the purpose of this precipitation of the lead from the anode lye, any useful
chemical precipitant may be used which is from the point of view of economy
capable of precipitating lead from its solutions without introducing other injurious:
matters into the solution instead of such lead.

page_text: being as follows:
wagam o enriched With Zine, the reaction
ZnR + Pb(NO,)2 = PbR + Zn(NO,).
insoluble..
By means of pure oxide of zinc and carbonic acid, white lead may be obtained.
Instead of these zinc compounds, where a cheaper solution of zinc is available and
where therefore a regeneration of the zinc solutions is not necessary, other harmless
precipitants may be utilized in precipitating the lead, such as alkaline chlorides,
bromides, chromates, sulphates, sulphites, sulphides, or similar compounds with
alkaline earths, sulphuretted hydrogen, ammonia, the alkaline earths themselves,
carbonates, and sometimes acids such as sulphurous or sulphuric acid and carbonic
acid; and finally also oxide of lead or compounds of oxide of lead, or substances
containing oxide of lead, which will form a nearly insoluble basic salt, when
brought into contact with the salt of lead contained in the anode lye. In some
cases, ie., where an inexpensive source of heat is available, the dissolved salt of
lead may be precipitated simply by a physical process, viz. by cooling, by diluting
the solution, or by the addition of an acid. In order to reliably prevent a diffusion
of lead from the anodes to the cathodes, sulphates, or other substances capable of
rendering the salts of lead insoluble, may be added to the circulating cathode lye
outside or inside the bath.
The lead compounds, such as sulphate of lead, chloride of lead; oxide of lead, or
sulphide of lead, precipitated in the manner herein before described and which as
above explained may vary extensively in their nature, may be utilized in any
convenient manner in the manufacture of peroxide, colours (or dyes), glass, and
other substances. It is essential, however, to note (a fact already alluded to) that
these compounds may be, at a very small cost indeed, restored to the metallic
state by coal, hydrogen, water gas or other reducing mediums, such as natural
sulphides, (galena or iron pyrites for example) preferably sulphides or pyrites
containing gold or silver and the lead may then be employed over again, in the
constant circulation process, as anodes.
Supposing it is desired to reduce to the metallic state from its oxide 206 kilo-
grammes of lead, 6 kilogrammes of carbon will suffice to effect the reduction.
Similarly chloride of lead (and also chloride of copper) may be reduced to
the metallic state by means of hydrogen, or water gas, or organic substances,
hydrochloric acid being formed at the same time, or free chlorine if air be suitably
admitted.
This hydrochloric acid and chlorine as well as sulphurous or sulphuric-acid
obtainable from the decomposition of chloride or of sulphate or of sulphite of lead
can be used over and over again for dissolving metallic oxides such as zinc oxide
and for regenerating the original solutions for instance of zinc.
In a similar manner it is possible to make use of the described lead-anode process
for obtaining also other metals by this electrolytic process,-such, for example,

page_text: s nickel, manganese, chromium, and even alkaline metals or alloys or amalgams
of the same, which are more electro-positive than lead. On the other hand, this
process is also available for the production of metals which are more electro-
begative, for example, silver, copper, bismuth, mercury iron or the like, all of which
may be obtained from their corresponding solutions. In this latter case a diaphragm'
s not absolutely necessary..
Here also it will naturally be likewise endeavoured to displace the lead in solution
(as is the case with zinc in the operations above described) by means of compounds
of the corresponding metal to be obtained, and more particularly by means of
sulphates, sulphites, chromates chlorides and oxides, and thereby, at the same time
to inaintain a uniform concentration of the metal contents of the lye.
In all these cases, the lead will constitute an excellent energy-saving or volt-
saving anode, capable of reducing the electromotive force at the pole by nearly
two volts and enabling its salts to be very readily and reliably separated again,
while at the same time,-being readily fusible,--it permits the metal to be
regenerated in a very economical manner, and in a solid or granulated state and
renders the employment of complicated filtering machines, in the precipitating
process, unnecessary, inasmuch as the compounds of the lead are heavy and readily
settle as they are precipitated.
Lastly, the silver contained in argentiferous lead (silver lead bullion) if such be
used for the anode, can be readily and completely extracted, since it remains
undissolved while the lead is being dissolved and separated.
Similarly to lead, mercury, though it is much more.expensive,—may be utilized
as an anode, inasmuch as it is still more readily recoverable as a metal, from its
compounds, than lead is.
But although lead appears to be the best and most economical material for
forming anodes which permit a considerable amount of electric energy to be saved
and are at the same time capable of being readily regenerated, yet, in some cases,—
especially where it is desirable that the anode should be of small specific weight,
other substances may be employed as substitutes for lead. Among these may be
instanced especially copper. In that case also, however, it is absolutely necessary
to prevent the anode solution from becoming too richly impregnated with the metal.
dissolved therein.
This anode solution, which,-where the anodes are lead,-must not, of course,
be a solution of pure sulphate, may, in the cases just mentioned (i.e., where copper,
is used), be a sulphate solution without any inconvenience, since this metal is not
insoluble as a sulphate. But in this case also, the anode solution should not absorb
more than from 50 to 75 grammnes per litre of the dissolved metal. Here also,,
therefore, the operation should be so conducted that the dissolved metal may be
precipitated or displaced by materials which are harmless,--more particularly
compounds of such metals as shall be obtained electrolytically.
The copper may be again separated in the well-known manner from a sulphate
or cupric solution, in the condition of cuprous chloride, oxy-chloride, oxide, prot-
oxide or sulphide conforming to British Patent 18080/1890.
In fact all the well known methods of precipitating metals may be employed,
provided they are capable of removing the metal dissolved at the anodes in a
harmless and economical manner.
In many cases it will be sufficient to obtain a precipitate of lead or copper
simply by the employment of lime or magnesia, and the salts thus obtained, such
Das chloride of calcium, may then be very readily utilised again for instance in the
production of chloride of zinc from oxide of zinc or carbonate of zinc, as, for
example, described in the Specification of British Letters Patent No. 11724 of 1894.
It has been stated above that by proceeding in the manner described i.e. by
using energy saving anodes, especially anodes made of lead, alkaline metals (as
5 well as the other metals previously mentioned) or, if desired, amalgams or alloys
It is therefore obvious that,
of the same, may be produced in an economical manner.
by this process, or, if required, with the additional employment of the known and
E

page_text: so-called quicksilver membranes, caustic alkalies and hydrogen may be obtained
instead of alkaline metals by allowing water to act upon the alkaline metals in the
nascent state. The same applies to caustic baryta and caustic strontia as well as
to other hydrates of metallic oxides. The produced hydrogen may be utilized for
reducing the sulphate or chloride of lead to the metallic state.
.
By this method, then, with the use of soluble anodes for instance the sulphates
of potassium, ammonium and even of sodium, which latter sulphate as is well
known is very cheap and almost worthless, may be profitably decomposed. In the
course of this operation, the sulphuric acid becomes fixed or bound on to the lead;
practically, the lead is first dissolved from the anode as a nitrate, chloride or
acetate and then precipitated by the sulphate of sodium, and is then by any known
smelting process separated from the sulphate of lead again in the metallic state,
whereby the sulphuric acid is recovered in the condition of sulphurous acid, while
at the same time, at the cathode, caustic alkalies are produced. The electrolytic
decomposition of the sulphates here takes place indirectly; soluble compounds of
lead being first produced at the anodes from solutions of alkaline compounds other
than sulphates, these lead compounds being subsequently decomposed or dis-
integrated by "duplex" decomposition through the action of the sulphates in
question, as follows
(3) PbN,O + Na,Cl₂ = PbCl, + Na.N₂O..
In the same way, just as in the case of production of zinc, also the chlorides of
the alkaline metals can be decomposed.
Furthermore it is evident that the alkalies in the nascent state may be converted
into their corresponding salts by admitting into their presence certain acids, such
as carbonic acid, phosphoric acid, boracic acid, oleic acid, or the like, so that
these acids directly combine with the said nascent alkalies thereby forming
the corresponding salts, such as carbonate, phosphate, borate, oleate and the
like.
Metal, such as zinc or nickel, may also be obtained simultaneously with caustic
alkalies, when the corresponding metallic oxides are dissolved or suspended in the
alkaline solution of the cathode; the oxides used being for instance the oxides of
zinc, lead or nickel. In this case metals are produced at the cathode instead of
hydrogen.
•
Sulphides or sulphurets of alkalies will likewise form at the same time with
metals if metallic sulphides or sulphurets, such as sulphide of antimony, sulphide
of lead, or iron pyrites, be in solution or suspension in the alkaline solution of the
movable cathode.
Where there is a strong acid at the cathodes, such for example, as hydro-
chloric acid or sulphuric acid, in the absence of a metallic salt, the only product.
of the electrolysis may be gaseous hydrogen but this is then obtained with so
small a voltage, that this method of producing hydrogen may be described as the
cheapest method conceivable owing to the fact that the lead anodes can be so
economically regenerated, and that the voltage of decomposition is very low.
Organic substances also, such as
"
" nitro bodies, may be treated by the
reducing process at the cathodes by the aid of this system of energy saving
anodes.
This principle of construction of energy saving anodes may be applied also to
the treatment by electrolysis of melted salts for instance of common salt. In such
case the lead anode is melted and lies at the bottom of the melting chamber or
vessel; over it, the cathode is placed, which should preferably cousist of tubes
capable of being heated internally; and between the anode and the cathode is

page_text: interposed the flux, such as common salt mixed with chloride of potassium or
other salts which lower the melting point.
Chloride of lead will then form at the anode, and upon sulphates, such as
sulphate of soda (Glauber's salt) or gypsum, being admittel to it, this chloride of
lead will decompose into sulphate of lead; or if brought into contact with lime, it
will decompose into oxide of lead; and the oxide of lead compounds, thus formed,
are reduced either outside, or (preferably) inside, the bath, by means of an
admixture of powdered charcoal. Hence carbon monoxide or dioxide will escape.
leaving behind lead in the regenerated metallic state so that in this case the
charcoal may be considered as the real anode substance.
The employment of energy saving anodes of lead or copper or other easily
reducible metals, such as bismuth, or alloys thereof enables convenient electrolytic
baths to be readily constructed and made to operate with a very low electromotive
force. It has also already been stated above that energy saving anodes, especially
if the latter be lead, in some cases are capable of yielding a surplus of energy
(like galvanic cells). This applies more especially to those instances where the
electromotive force required for the decomposition of certain fluids is less than
the electromotive force set up by the act of dissolving the lead,-which amounts
to about 1.8 volts. Such is the case, for example, where the salts of copper or
silver, or solutions of nitrates or nitrites or nitro bodies are decomposed by the
aid of lead anodes.
Hence it follows that these energy saving anodes, especially lead, which is
insoluble in diluted acids, but may be readily reduced from its compounds-may
very advantageously also be utilized as anodes in galvanic batteries, as substitutes
for zinc. Or the zinc consumed in galvanic batteries may be regenerated by the
use of anodes of lead.
The aim to which the process herein described mainly tends is to enable coal or
other cheap fuel to be indirectly used in making anodes in saving or producing
electricity or in other words to take advantage of the chemical energy inherent in
carbon, in carrying out electrolytical operations, by using anodes which are readily
and economically reducible to the metallic state. by the action of coal or water
gas or the like.
The dynamic production of electricity has only, hitherto, utilised about ten
per cent. of the energy inherent in carbon, whereas the present process enables a
far greater proportion of the energy thus generated to be satisfactorily turned to
account. Two-thirds to three-fourths of the electromotive force necessary for
chemical decompositions can henceforward be supplied by direct transformation of
chemical into electrical energy.
Carbon for itself when directly transformed by electrolysis into oxide of carbon
is not capable of furnishing more than 75 volts, whereas by the herein described
system it furnishes indirectly about 2 volts.
Carbon moreover has the drawback of being a nonconductor of electricity
whereas its "substitute and product "the lead is a good one.
Lastly, conforming to this process, besides coal, other sources of energy, hitherto,
completely neglected, such as pyrites or galena can be utilized.
Having now particularly described and ascertained the nature of my said inven-
tion and in what mauner the same is to be performed, I declare that what I
claim is
1. In electrolytic or galvanic processes for the production of products materially
or substantially independent from the substance of the anode, the method of
employing soluble anodes, the metal of which being readily precipitable from its
solutions differs from the metal of the final product to be obtained at the cathode
and is practically insoluble in diluted acid (especially in diluted sulphuric acid)
so as to exclude zinc and iron from the employment for such anodes, and of
preventing the metal of the anodes, which; [dissolves during the process in the
:

page_text: anode liquid, to reach the cathodes by removing this metal from the said anode
liquid during the process either physically or chemically substantially as herein-
before described.
2. In the method according to Claim 1, the employment of anodes consisting
of lead or plumbiferous substances, compounds or alloys in a compact, pulverulent
or spongious condition or of other metals (such as mercury copper or the like)
or compounds or alloys thereof substantially as described.
3. In the method according to Claim or 2 the operation of removing the
dissolved anode metal from the anode liquid by chemical or physical precipitation
and then preferably restoring such precipitates to the metallic state by means of
reducing agents such as coal, water gas or the like, substantially as described and
for the purpose set forth.
4. In the method according to Claims 1-3 the operation of directly decomposing
compounds or salts (such as acetate of zinc) and subsequently precipitating the
metal of the anode, which has been dissolved in the anode liquid, by means of the
salt or oxide to be indirectly decomposed) such as sulphate of zinc) thereby
regenerating the electrolysed intermediate substance (such as acetate of zinc)
substantially as described and for the purpose set forth.
5. The employment of the method above characterized for the manufacture of
metals (such as zinc) alloys or amalgams substantially as described and for the
purpose set forth.
6. The employment of the method above characterized for the manufacture of
oxides, or hydroxides of metals, substantially as described and for the purpose set
forth.
7. The employment of the method above characterized for the manufacture of
carbonates, phosphates, oleates or of other salts derived from oxides substantially
as described and for the purpose set forth.
8. The application of the method above characterized for the manufacture of
hydrogen or for reducing (deoxidizing) organic substances, substantially as
described and for the purpose set forth.
9. The application of the method above characterized for the electrolysis of
molten substances, substantially as described and for the purpose set forth.
10. The application of the method above characterized for the production of
positive electricity, especially by the employment of soluble plumbiferous anodes
substantially as described and for the purpose set forth.
11. The application of the method above characterized for refining lead and
for the manufacture or regeneration of sulphuric, sulphurous and hydrochloric
acid, substantially as described and for the purpose set forth.
12. In the method, above characterized the application of movable anodes,
substantially as described and for the purpose set forth.
13. In the method above characterized the application of movable cathodes,
substantially as described and for the purpose set forth.
14. In the method above characterized the method of heating the solutions,
substantially as described and for the purpose set forth.
15. The application of the chlorides (such as chloride of calcium) formed by
the decomposition of the chloride of lead or other metals for instance copper in
the method above characterized for the leaching of ores, especially zine ores,
substantially as described and for the purpose set forth.
Dated this 20th day of June 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.