Electrolytic Production of Amalgams and their Utilization.
Year: 1895

page_text: Date of Application, 9th Aug., 1895-Accepted, 8th Aug., 1896
COMPLETE SPECIFICATION.
Electrolytic Production of Amalgams and their Utilization.
EMILE ANDREOLI, Journalist of 18 Somerleyton Road London S. W. GABRIEL
ANDREOLI, Electro Chemist of 18 Somerleyton Road, London S.W. 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 object of this invention is the electrolytic production of amalgams and
their utilization with or without the electric current for coating copper or other
metal plates in a simple economical and instantaneous manner and thus rendering
them available for the recovery of gold or silver by amalgamation, or in the mortar
mill where the auriferous ores are crushed, or for other suitable purposes.
We shall hereafter describe the formation of an amalgam of sodium and a
process for coating copper, or other metal plates with mercury, so as to render them
available for amalgamating gold or silver."
In the ordinary way, this coating requires skilled labour and consists of
troublesome operations for scouring and pickling the copper plates before they can
absorb quicksilver, but according to our invention, as soon as the amalgam comes
in contact with the plates of copper, or other metal, they become thoroughly
amalgamated without having been submitted to any scouring, cleansing, or
pickling.
One of our apparatuses consists of a vessel where the amalgam is prepared,
which we will call the electrolyser, Fig. 1, and a tank or vat, which we will call
the amalgamator, Fig. 5.
Fig. 1 shows the electrolyser ready for working.
a is a vat made of slate or earthenware, or other convenient material, which is
divided into positive and negative compartments, formed by porous partitions.
In the following description of the working of the electrolyser, we will take as
an illustration the formation of an amalgam from a concentrated chloride of sodium
solution.
The positive compartments b, b, contain anodes made of iron or copper plates, or
pieces of retort carbon surrounded by pieces of iron or by lime. As soon as the
current passes through the solution, chlorine is formed in the positive compartments,
but combines with the metal or with the lime and thus the smell and fumes of
chlorine are avoided. We may, however, if wanted, collect the chlorine gas by
some known means.
The sodium: goes to the negative compartment c, which is full of mercury d, with
which it unites and forms a sodium amalgam. As soon as the mercury has absorbed
a sufficient quantity of sodium, i.e. when the sodium amalgam is rich enough to
amalgamate the copper, we open the tap f, to allow it to run through the pipe
into the amalgamator; the electrolyser is refilled with fresh mercury and the
electrolytic operation continues with formation in the same manner of chlorine or
chlorine compounds at the positive, and sodium amalgam, at the negative pole.
From time to time the chloride of sodium solution is strengthened by the addition
of more salt.
We may
The partitions can be made of porous porcelain or similar material.
also have them constructed in the following manner: Fig. 2 shows a framed
perforated slate plate a. On the side facing the anolyte where chlorine is formed,
we cover this perforated plate with rods b, made either of glass, porcelain ebonite,
paraffined wood and the like (Fig. 3), which we fix on the slate, close one to the

page_text: of liquida.
To make sure that there is no liquid passing from the positive to the negative
compartments, we cover the glass or other rods with a layer of peroxide of
manganese, which kept in situ by a second perforated plate of slate, ebonite, or
other convenient material, provided with glass, porcelain, or other rods as herein-
before described.
Fig. 4 shows the diaphragm.
a al is the perforated slate plate.
bis the series of rods.
e is the layer of peroxide of manganese.
The amalgamator (Fig. 5) is a large shallow vat divided into three compa rtments.
The two outer ones a, a, are filled with a concentrated solution of chloride of
sodium and are provided with suitable anodes while in the middle compartiment C,
the sodium amalgam arrives from the electrolyser, is connected to the negative pole
of the source of electricity, so that while the copper or other metal plates are
being amalgamated, more metallic sodium is being supplied to the mercury from
the outer compartments, and partly keeps the strength of the amalgam.
The amalgamator can be used dry, but it is sometimes advisable to cover the
mercury amalgam with water.
Our apparatus can be constructed in any convenient shape or size and we do not
confine ourselves to any particular form or dimension.
Fig. 6 shows a tank in which the central negative compartment is provided with
a concave bottom, in which the mercury collects and absorbs the alkaline metal
under the electrolytic action which takes place between it and the positive
compartments.
We employ this apparatus for economical reasons because it only requires a
small amount of mercury at the bottom, but in order to expose a larger area to the
electrolytic action, the quicksilver is preferably covered with sufficient water to
fill up the cathode compartment, between the two positive compartments which are
full of chloride of sodium solution.
The curve can be much more gradual than is shown in Fig. 6, and we can vary
it according to the length, flexibility, or rigidity of the plates to be amalgamated.
To make certain of the plate to be amalgamated coming in thorough contact
with the mercury amalgami, we may fix iron guides or rollers r, r, r, r, in the
central compartment under which the metal plates slip and are led from one end of
the amalgamator to the other.
The following arrangement enables us to produce sodium amalgam on a large
scale and to amalgamate large surfaces of metal plates with a comparatively small
amount of mercury.
The apparatus in Fig. 7 which may be of any dimensions is divided into three
compartments a, b, a, by means of porous partitions, as hereinbefore stated.
a, a, are the positive compartments. Under ordinary circumstances, the central
compartment would require an enormous quantity of mercury to he proportionate
with the surface of the porous diaphragms which separate the anode and cathode
compartments, and still the process could not be worked since the pressure of this
considerable quantity of quicksilver filling up the compartment would break the
porous partitions, or the quicksilver would penetrate into the positive compartments,
but we do away with this difficulty, which would make the process inapplicable
by adopting a well-known contrivance, which consists in fixing in the central
compartment a mass d of cement or other substance in such a manuer as to leave
only a small interspace between it and the porous partitions, which a small quantity
of quicksilver will fill up. If this mass d is now covered with mercury e, we
have a layer of mercury spread on and around a large copper amalgamated
surface acting as cathode in combination and contact with a thin vertical lamina
of mercury, thus forming an uninterrupted layer of mercury on the top of the
' amalgamated mass, when the sodium being lighter rises as fast as it is produced

page_text: by the electrolysis between the sides of the above mentioned amalgamated mass
and the porous diaphragm. Thus however wide and long may be the thin layer of
mercury on the top of the amalgamated mass, however shallow or deep may be the
compartments, the conductivity and efficiency of the electrolytic apparatus will be
at the maximum, and plates 40 sq. feet woull be as well and rapidly amalgamated
as if their surface was only 4 feet.
The pressure of the mercury on the porous diaphragms is reduced to a minimum
by inserting in the gap close to them as many perforated sheets of copper or
other metal, which lessen the quantity of mercury to be used on all sides of the
amalgamated mass.
The reaction which takes place is so well known that we need not insist on it.
The sodium is deposited on the vertical mercurial cathodes and rises to the surface
where the layer of mercury which covers the amalgamated mass, absorbs it and
forms an amalgam as rich as required, which may be used with or without the
aid of the electric current, either for mercurizing copper or other metal plates, or
in the mining districts for the recovery of gold in the batteries, or in amalgamating
pans or from its solutions. We may also have amalgamated lead, or porous lead,
or the like, or an alloy of metals in the gap between the amalgam ited mass and the
positive compartments. In this manner, the mercury which covers the amalgamated
block is in contact and in combination with their vertical cathodes formed by
amalgamated porous lead or copper filings, and the like, and with perforated
amalgamated sheets of copper as hereinbefore stated.
Other arrangements of the same kind can be devised for obtaining a large
surface with a minimum quantity of quicksilver in the commercial production and
application of amalgam. The one which we prefer is the last one (Fig. 7), but we
may adopt other apparatuses constructed on the same principle.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. The production of amalgams by the electrolytic decomposition of a concen-
trated solution of chloride of sodium, or other solution, which may supply sodium
or potassium or other alkaline metal to a very large surface of mercurial cathode
as herein before described and illustrated.
2. The use in the production and application of a soliun amalgam for the
mercurization of copper plates and for other purposes of compartments formed
by porous diaphragms substantially as herein before specifically described and
illustrated.
3. The construction and use of an electrolyser and of an amalgamator as repre-
sented in Fig. 5, or of an apparatus as represented in Fig. 7 for the production and
the supply of amalgam.
4. The instantaneous mercurization of copper or other metal plates when in
contact with the analgam electrically produced and revivified as herein before
stated.
5. The above described arrangement Fig. 7 for obtaining a large surface of
mercury in the negative compartments for the purposes herein before set forth.
6. The combination of a layer of mercury on the upper part of an amalgamated
mass in the negative compartment with thin mercurial cathodes as specifically
described and illustrated and for the purposes set forth.
Dated this 9th day of August 1895.
EMILE ANDREOLI.
GABRIEL ANDREOLI.