Improvements in the Process for Obtaining Zinc by Electrolysis.
Year: 1889

page_text: Date of Application, 30th Oct., 1889.
Complete Specification Left, 30th Aug., 1890-Accepted, 4th Oct., 1890
PROVISIONAL SPECIFICATION.
f
Improvements in the Process for Obtaining Zinc by Electrolysis.
I, ALEXANDER STANLEY ELMORE of The Mount Rothwell in the County of York,
Electrometallurgist do hereby declare the nature of this invention to be as follows:
My invention relates to means of obtaining zinc in a pure and compact condition'
by electrolytic deposit from a solution of a salt of zinc such as zinc sulphate.
For this purpose, I provide an electrolytic bath of wood or material not acted on by
the contents, and in this bath I place a porous cell or several such cells, or, instead of
separate porous cells, I divide the bath in compartments separated by a porous screen.
I supply the bath with zinc sulphate solution and I provide a siphon or other overflow
from the porous cell or the corresponding compartment at a little lower level than that
of the solution in the bath so as to promote the flow through the porous screen or
porous sides of the cell or cells. In these or in the corresponding compartment,"I
place an anode or several anodes, preferably of metal sucli as iron, which readily
combines with the sulphuric acid liberated by the decomposition of the zinc sulphate, this
having tho effect of checking polarisation of the bath and of lessening the amount of
electric energy required to be supplied for the decomposition of the zinc sulphate. When
the anodes are of material not readily acted on by the sulphuric acid, I cause the overflow
from the cells or compartment to pass through a body of zinc oxide or carbonate; so
as to become again a solution of zinc sulphate, to be returned to the bath for subsequent
decomposition. The cathode or cathodes may be of iron or other metal, each of them
being in the form of a disc or cylinder which is caused to revolve submerged in the
liquid of the bath, while a burnisher is moved to and fro along its surface pressed
thereon by a weight or spring.
The anodes and cathodes being connected respectively to the terminals of a dynamo
electric machine or of a battery or other source of electricity, the zinc becomes
deposited on the cathodes; but instead of being in the loose granular state such as it
would have under the ordinary conditions of electrolytic deposit, it is rendered
compact, close in texture and coherent by the burnishing to which it is subjected as it
is being deposited. When the deposit has attained the desired thickness, the zine can
-be removed in the form of round plates from the discs or it can be cut longitudinally
and stripped off the cylindrical cores.
Although I have mentioned zinc sulphate as the salt treated, other compounds of
zinc, such, for instance, as the acetate may be similarly treated.
Dated this 30th day of October 1889.
1
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Process for Obtaining Zinc by Electrolysis.
I, ALEXANDER STANLEY ELMORE of The Mount, Rothwell, in the County of York,
Electrometallurgist, 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
-
My invention relates to means of obtaining zinc in a pure and compact condition by
electrolytic deposit from a solution of a salt of zinc such as zinc sulphate.
1
For this purpose I provide an electrolytic bath of wood or material not acted on by
the contents, and in this bath 1 place a porous cell or several such cells, or, instead of
separate porous cells I divide the bath in compartments separated by a porous screen.
I supply the bath with zinc sulphate solution and I provide a siphon or other overflow
D

page_text: from the porous cell or the corresponding compartment at a little lower level than that
of the solution in the bath so as to promote the flow through the porous screen or
porous sides of the cell or cells. When the porous cell or screen is of somewhat close
texture, I provide holes through it at the level at which the liquid in the bath is
desired to stand, so that if the liquid should rise above that level it will overflow into
the cell or compartment. In these or in the corresponding compartment I place an
anode or several anodes preferably of metal such as iron which readily combines with
the sulphuric acid liberated by the decomposition of the zinc sulphate, this having
the effect of checking polarisation of the bath and of lessening the amount of electric
energy required to be supplied for the decomposition of the zinc sulphate. When the
anodes are of a kind having little or no solubility, it is of advantage for reducing
polarisation to introduce into the porous cell or compartment substances capable of
absorbing or combining with the gas or other matter set free at the anode. If, for
example, oxygen be liberated at the anode, some lower oxide of sulphur introduced
into the porous cell or compartment would take up the oxygen forming higher oxides.
In this way the electromotive force as measured at the terminals of the cell might be
considerably reduced. When the anodes are of material not readily acted on by the
sulphuric acid I cause the overflow from the cells or compartment to pass through a
body of zinc oxide or carbonate so as to become again a solution of zinc sulphate to be
returned to the bath for subsequent decomposition. The cathode or cathodes may be
of iron or other metal each of them being in the form of a disc or cylinder which is
caused to revolve submerged in the liquid of the bath while a burnisher is moved to
and fro along its surface pressed thereon by a weight or spring.
The anodes and cathodes being connected respectively to the terminals of a dynamo
electric machine or of a battery or other source of electricity the zinc becomes
deposited on the cathodes but instead of being in the loose granular state such as it
would have under the ordinary conditions of electrolytic deposit it is rendered compact
close in texture and coherent by the burnishing to which it is subjected as it is being
deposited. The purity of the deposited metal is also maintained by the action of the
porous partition which prevents the products of decomposition that appear at the anode
from reaching the cathode. When the deposit has attained the desired thickness the
zinc can be removed in the form of round plates from the discs or it can be cut longi-
tudinally and stripped off the cylindrical cores.
Although I have mentioned zinc sulphate as the salt treated other compounds of
zinc such for instance as the acetate may be similarly treated.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The herein described process for obtaining zinc in a pure and compact condition by
electrolytically depositing it on a revolving cathode subject to the action of a burnisher
in a bath of sulphate or other salt of zinc in which the compartment containing the
anode or anodes is separated as a porous cell or by a porous screen from that containing
the cathode or cathodes.
Dated this 30th day of August 1890.
ABEL & IMRAY,
Agents for the Applicant.