Improvements in the Art of Producing Insoluble Chlorides Direct from the Metals.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in the Art of Producing Insoluble Chlorides Direct
from the Metals.
I, STANLEY CHARLES CUTHBERT CURRIE, a subject of the Queen of Great
Britain, but now residing at Room 841 Drexel Building, Fifth and Chestnut
Streets, in the City of Philadelphia in the County of Philadelphia and State of
Pennsylvania, Electrical Engineer, do hereby declare the nature of my invention
for IMPROVEMENTS IN THE ART OF PRODUCING INSOLUBLE CHLORIDES DIRECT
FROM THE METALS, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statements :-
My present invention relates to the manufacture of insoluble chlorides, such as
those of lead, silver and mercury or calomel direct from the metals lead, silver and
mercury.
The principal object of my invention is to provide a simple, inexpensive, cou-
tinuous and expeditious method of electrolytically producing insoluble chlorides
such as those of lead, silver and mercury (Hg,C₁₂) or calomel, direct from the
metals lead, silver and mercury.
In carrying my invention into effect use is made of an electrolytic vase or cell
containing a neutral electrolyte, as a neutral solution of chloride of zinc. Any
preferred form of electrolytic cell may be employed for this purpose, but for the
sake of a further description of my invention, I have illustrated in the accom-
panying drawing, a central section of an electrolytic cell that has been found
practically efficient and have indicated in writing on said drawing the composition
and arrangement of the respective parts in the production of chloride of mercury
or calomel by my improved process.
In the drawing A, is a vase or cell. B, is a cup or other preferred form of
receptacle suitably supported in the vase or cell A, and adapted to contain mercury.
This receptacle B, is made of a substance or material that is not in any way
affected by the mercury which it contains, or by the electrolyte, or by the chemical
or electrical actions which take place in the cell A. The mercury contained in the
vessel B, is constituted an anode by immersing into it the extremity of a conductor
leading from a dynamo or other source of electricity.
The metal to be converted into an insoluble chloride as lead, silver or mercury
is constituted the anode in the electrolytic vase or cell. The cathode of the cell
or vase may consist of any suitable substance or material as lead or zinc.
Preference, however, is given to the employment of a zinc cathode. The electro-
lytic cell is then subjected to the action of an electric current resulting in the
decomposition of the electrolyte into its constituent radicals, which in the present
instance is into metallic zinc and chlorine. The metallic radical zinc, is then
deposited at the cathode and may be subsequently recovered by a reversal of the
electric current or in any other preferred manner, and the acid radical, in the
present instance chlorine, goes to the anode and unites and chemically combines
therewith, forming an insoluble chloride as mercury or calomel (Hg,Cl,), chloride
of lead or chloride of silver. This insoluble chloride collects in the electrolytic
vase or cell and may be removed therefrom and washed for subsequent use.
My invention is distinguishable from the ordinary electrolytic action in the
following particulars:-In the ordinary electrolysis the acid radical of the
electrolyte appears in a gaseous state or condition at the anode if the latter is
insoluble in the bath or electrolyte, but if the same is soluble in the bath or
electrolyte then the acid radical does not appear as a gas, but the anode is dis-
integrated, and after being dissolved in the solution is deposited on the cathode

page_text: use.
In other words, the anode is gradually transferred to the cathode. In my process
the salt formed at the anode, in the present instance, insoluble mercurous
chloride, chloride of silver or chloride of lead, is not reduced and deposited at
the cathode, but collects in the vase or cell, from which it may be removed for
Moreover, according to my invention the operation of converting the anode
into an insoluble chloride may be performed in an exceedingly rapid manner.
These improved results, namely, the deposition in the vase or cell of the insoluble
chlorides, such as the chlorides of silver, lead or mercury are attributable
to the employment of a neutral electrolyte, such as a solution of chloride
of zinc.
In order to reduce the resistance of the electrolyte there may be mixed
with the chloride of zinc a certain proportion of chloride of sodium or of chloride
of potassium, but however, in practice, preference is given to the employment of.
chloride of zinc.
My invention therefore comprises the improvement in the art of manufacturing
insoluble chlorides, such as those of silver, lead or mercury electrolytically from
mercury, silver and lead, which consists in employing a neutral electrolyte, such as
a solution of chloride of zinc alone or with another material or materials.
My invention further comprises the process of manufacturing insoluble chlorides,
such as mercury, silver or lead, which consists in constituting mercury, silver or
lead, the anode in an electrolytic cell in a neutral solution of chloride of zinc alone
or with an added substance or materials, and electrolytically converting the
inercury, silver or lead into their respective insoluble chlorides; and
My invention further consists in the improvements in the manufacture of
insoluble chlorides direct from the metals in the manner hereinafter described and
pointed out in the claims.
In order that the nature and objects of the invention may be more fully under-
stood, a brief description of the process of electrolytically producing calomel direct
from metallic mercury will now be given, but it must be borne in mind that the
invention is not confined to the production of calomel.
In practice use is made of an electrolytic cell A, containing a neutral solution,
such as chloride of zinc. Mercury is then constituted the anode of the cell by con-
necting the same with a conductor or placing the same in a suitable receptacle B,
in connection with the proper conductor. The cathode of the cell may be of any
suitable material or substance, but however, preference is given to the employment
of a zinc cathode. The passing of an electric current through the electrolyte
causes a decomposition of the chloride of zinc into zinc and chlorine. The chlorine
goes to the anode and uniting with mercury to form mercurous chloride or calomel,
as it is sometimes called, and the zinc goes to and is deposited upon the cathode.
The calomel separates from the anode and is deposited in the vase or cell A, and
may be removed therefrom and washed for use. The zinc may be recovered from
the cathode and the electrolyte again brought to the neutral condition.
Having now particularly described and ascertained the nature and objects of my
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. The herein described method of producing insoluble chlorides direct from the
metals, which consists in constituting the metal or metals to be converted into a
chloride or chlorides the anode in an electrolytic cell in a neutral chloride solution
and then converting the metal or metals into an insoluble chloride or chlorides,
substantially as and for the purposes set forth.
2. The herein described method of producing insoluble chlorides direct from
the metals, which consists in constituting the metal to be converted the anode
in an electrolytic cell containing a neutral metallic chloride solution such as
chloride of zinc alone or with another substance or materials and then electro-
lytically converting said metal into an insoluble chloride, substantially as and for
the purposes set forth, -

page_text: 3. The herein described method of producing insoluble chlorides, such as the
chlorides of silver, lead and mercury, which consists in constituting the metals
to be converted as lead, silver and mercury the anode in .a
.a neutral metallic
chloride electrolyte or bath as chloride of zinc, and electrolytically converting
the metals into insoluble chlorides, substantially as and for the purposes set
forth.
Dated thin 19th dex of Au 1901
STANLEY CHARLES CUTHBERT CURRIE.
W. P. Thompson & Boult,
Agents for the Applicant.