THE PRODUCTION OF MATERIALS TO BE EMPLOYED IN THE CONSTRUCTION OF ELEMENTS FOR VOLTAIC BATTERIES AND APPARATUS TO BE USED THEREFORE
Year: 1885

page_text: We DESMOND GERALD FITZGERALD of 6 Akerman Road, Brixton, in the County
of Surrey, Electrician, and THOMAS JOHN JONES of 12 Princes Street, Hanover
Square, in the County of Middlesex, Electrician do hereby declare the nature of
our invention for "THE PRODUCTION OF MATERIALS TO BE EMPLOYED IN THE
CONSTRUCTION OF ELEMENTS FOR VOLTAIC BATTERIES AND APPARATUS TO BE
USED THEREFORE," and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Hitherto in primary batteries zinc has been almost exclusively employed as the
positive element, being ordinarily converted into the sulphate of the metal. The
experience of many years has, however, shown that it is impossible economically to
recover the zinc in the metallic form from this salt, either by chemical or by
electro-chemical means. In lieu of zinc, we employ, as the positive element, the
metal lead which is readily reducible from most of its compounds, either by
chemical, metallurgical, or electro-chemical means. The active portion of this
element is lead in a more or less porous or spongy condition as obtained by the
compression of finely divided lead (obtained in bulk) by the electrolytic reduction
of the metal from one of its oxides or salts. The metal lead when in this porous
condition constitutes an excellent positive element for batteries, as, for instance, in an
electrolyte of dilute sulphuric acid which almost wholly converts it into sulphate
of lead when the circuit is closed, without the production of an efflorescent salt,
such as the sulphate of zinc which is so inconvenient and detrimental in voltaic
batteries wherein zinc is employed as the positive element. As the negative
elements, we employ a conductor (preferably lead or carbon) coated or maintained
in contact with peroxide of lead.
Our present Invention relates to the production of spongy or finely divided lead
and peroxide of lead to be employed in the construction of elements for voltaic
batteries, and it consists in obtaining, by means of electrolysis, the finely divided
or spongy lead in bulk from a paste composed of equivalents of sulphate of lead
and magnesia with water or other suitable liquid, or of sulphate of lead with an
alkaline solution, and simultaneously therewith the peroxide of lead, either in bulk,
or as a coherent layer upon the surface of a conductor preferably of lead from red
.5

page_text: lead or litharge, or a mixture of either with finely divided lead, or from sulphate of
lead (such as the spent materials from the working of lead batteries) which has been
treated with an alkaline solution.
The Invention also relates to the construction of the electrolytic or converting
tanks employed, by means of which we are enabled to obtain materials to bo
employed for elements of voltaic batteries from the above mentioned or other lead
compounds.
The Invention will be described with reference to the accompanying drawing,
wherein Figures 1 2 and 3 show respectively a longitudinal section, plan, and cross
section of a converting tank or trough wherein both the materials for the con-
struction of a battery (i,e, spongy lead and peroxide of lead) are produced in bulk
while figures 4 and 5 show a longitudinal section and plan of another form of tank
or trough in which the spongy lead is obtained in bulk and the peroxide of lead
upon a plate of suitable conducting material.
Referring to figures 1, 2 and 3, A is an electrolytic trough of convenient
dimensions furnished on each side with a mercury receptacle a, a, and b b and
containing a number of sets of horizontal leaden trays T and T arranged side by
side. These trays are superposed as shown and each tray is supported at a few
inches distance from the one next above and below it. The trays are coated
externally with some impervious material such as marine glue and the copper or
leaden wires supporting them are similarly coated. These sets of trays are
alternately connected by means of insulated supporting wires w and w¹ with the
mercury in receptacles a, a and b, b, and constitute in fact negative and positive
electrodes within the trough. The trays constituting each electrode are connected
together by the supporting wires or rods w, w¹, which, as will be seen by figure 3,
rest at one side on the edge of the tank or trough, while at the other side said wires
are bent down so as to dip in the mercury.
The positive (anode) trays T contain the compound of lead to be converted into
peroxide of lead. This may be red lead or litharge preferably made into a paste
which is preferably allowed to become dry and to harden prior to the electrolytic
conversion. We obtain a good result by mixing the red lead or litharge with from
10 to 30 per cent of finely divided lead and also with a solution of caustic alkali
or a solution of sulphate of magnesia in sufficient quantity to form a pasty mass
which is spread upon the bottom of the tray. Or the spent material (consisting
mainly of sulphate of lead in admixture with peroxide of lead) resulting from the
action of lead primary batteries in which sulphuric acid or a sulphate in solution
is the electrolyte, may be used in lieu of the red lead or litharge if previously
treated with an alkali. The pasty mass, before drying, may be divided or marked
out (by means of paste cutter" or otherwise) into portions of suitable size to
constitute anodes or "depolarising slabs" for various forms of battery.
"
The negative (cathode) trays T₁ are filled with a similar pasty mass of oxide of
lead (litharge) or of a mixture composed of equivalents of sulphate of lead and
magnesia (i,e of about one part by weight of magnesia to seven and a half parts of
lead sulphate) or with a paste made of sulphate of lead and an alkaline solution
such as that of caustic soda. The electrolyte within the electrolytic trough may
be a half saturated solution of sulphate of magnesia, but a solution of an alkaline
sulphate or dilute sulphuric acid may be employed.
When a current from a dynamo machine the poles of which are connected to the
terminal binding screws (+ and -) of the trough is caused to pass in the direction
from the positive to the negative trays, the lead compound in the former (T)
becomes converted into peroxide of lead, whilst the lead compound in the latter (T¹)
becomes reduced to finely divided metallic lead. Elements may be manufactured
or constructed with these materials by various means which are known or have
been fully described, and the "spent" materials from these elements, after they
have served in the battery, may be reconverted within the trays of the above
mentioned electrolytic trough, the sulphate of lead from the positive elements of
the battery being removed from these elements, treated with an alkaline solution

page_text: or mixed with its equivalent of magnesia, and introduced into the trays T¹ connected
with the negative pole of the dynamo machine, whilst the spent material from the
negative elements of the battery which may also be treated with an alkaline
solution, is placed within the trays T.
The process may be varied by manufacturing in bulk within the trays of the
electrolytic trough, shown in figures 4 and 5, only one of the materials required
for manufacturing the elements, this material being usually the finely divided lead
used for the positive elements. The other material, viz-peroxide of lead, is, in
this case, obtained within the electrolytic trough upon the surface of the plates d d
intended for the negative elements of the battery. These plates are placed as
anodes within the electrolytic tank between the sets of trays constituting the
cathodes and containing the material to be reduced to the metallic form. The
plates in question may be simply of lead, either plain, roughened, perforated, or
corrugated. In this case especially we find it advantageous to use as the electrolyte
within the electrolytic trough or tank, a solution of sulphate of magnesia which
may be half saturated or of greater strength and which from time to time requires
to be neutralised by the addition of magnesia, or carbonate of magnesia, since it
tends to become strongly acid by the effect of electrolysis. By the use of this
electrolyte, we are enabled to obtain upon a plain or uncoated plate of lead, a layer
of the peroxide of this metal of sufficient thickness to render the plate an efficient
negative element for a voltaic battery, whereas, by the use of dilute sulphuric acid
for instance, the layer of peroxide formed by one operation of electrolysis is merely
superficial and' altogether insufficient to convert the plate into an efficient negative
element. But, when negative elements of greater capacity than those obtained
from plain sheets of lead are required, we prepare such elements by coating a sheet
of lead, by preference roughened or perforated with fine holes, with a paste formed
of oxide of lead (litharge) of red lead, or of a mixture of either of these and finely
divided lead with water or other suitable liquid, allowing such paste to become dry
and hard (and in some cases wrapping the coated plate in canvas or felt secured by
indiarubber bands or otherwise) and subsequently subjecting this prepared plate to
electrolysis as an anode in an electrolyte which in this case may be either a solution
of sulphate of magnesia, dilute sulphuric acid, or an alkaline sulphate. When
finely-divided metallic lead is employed as above (i,e, in admixture with an oxide
of lead), it should be allowed to become oxidised which it readily does in the process
of drying. Or these plates intended to serve as negative elements in the battery,
may, in the first place be coated with reduced lead obtained by electrolysis from a
mixture of equivalents of sulphate of lead and of magnesia, or may otherwise be
coated or prepared with finely divided lead, which is subsequently converted by
electrolysis into peroxide of lead. We find it advantageous to consolidate the
electrolytically reduced lead upon the. plate by a moderate pressure prior to the
conversion of the lead into peroxide.
Negative elements for our battery so manufactured or the negative elements of
merely electrolytically-coated lead may, when exhausted, be treated by dipping
them into a solution of caustic alkali (which can be economically prepared and
maintained in suitable condition by the addition of lime or its hydrate to a solution
of sulphate of soda or of sulphate of potash) and afterwards subjecting them to
electrolytic action as anodes, using preferably a solution of sulphate of magnesia
in the electrolytic troughs and dilute sulphuric acid in the battery troughs. The
manufactured negative elements may thus be employed a number of times without
e-making. The positive elements manufactured from the reduced finely divided
ead are, in this process, re-made every time after use.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed, we declare that what
ve claim is
1st The use, for the purpose of electrolytically obtaining in bulk materials for
he elements of voltaic batteries, of a paste composed of equivalents of sulphate

page_text: of lead and magnesia, or of sulphate of lead and an alkali, substantially as
specified.
2nd The production of a negative element for a voltaic battery by subjecting a
lead plate to electrolytic action as an anode in a solution of sulphate of magnesia,
in conjunction with a cathode consisting of a number of superposed tray's con-
taining a lead compound to be reduced to the metallic form, substantially as
specified.
3rd The treatment of sulphate of lead obtained as the spent material in the
working of lead primary batteries with an alkaline solution prior to reconverting
such sulphate into peroxide of lead by electrolysis substantially as specified.
4th The construction of electrolytic converting tanks or troughs in which both
the electrodes are constituted by a number of sets of superposed trays (preferably
of lead) containing the materials to be acted upon electrolytically, substantially as
shown and described.
5th The construction of electrolytic converting tanks in which one electrode is
constituted by a number of sets of superposed trays containing the substance to
be acted upon electrolytically, and in which the other electrode is constituted by
plates either plain or coated with another substance to be acted upon electro-
lytically, which plates intervene between the above mentioned sets of trays,
substantially as shown and described.
Dated this 3rd day of February 1885.
DESMOND G. FITZGERALD.
T. J. JONES.
By their Agents, A. M. & Wm Clark,
53, Chancery Lane, W.C.