Improvements in and Means to be Employed for the Obtainment of Zinc from its Ores, and the Electro-deposition of Zinc upon Iron or other Metals or Alloys.
Year: 1895

page_text: Date of Application, 11th Feb., 1895
Complete Specification Left, 11th Dec., 1895-Accepted, 11th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements in and Means to be Employed for the Obtainment of
Zinc from its Ores, and the Electro-deposition of Zinc upon
Iron or other Metals or Alloys.
We, THE COWPER-COLES GALVANIZING SYNDICATE LIMITED of 39 Victoria
Street in the City of Westminster and SHERARD OSBORN COWPER-COLES of
16 Adam Street Manchester Square in the County of London Engineer do hereby
declare the nature of this invention to be as follows:-
or
This invention relates to the obtainment of zinc from its ores and the electro-
deposition of zinc upon iron, or other metals, or alloys, and has for one of its
objects to provide means whereby a good, and bright thick deposit of zinc can be
obtained in an efficient manner, without the formation of zinc sponge. There is
employed according to this invention in the depositing tauk or cell, an electrolyte,
or solution, composed of zinc sulphate to which is added iron-sulphate. Excellent
bright deposits of zinc upon iron can, for example, be obtained by using the
following proportions of the constituents to each gallon of water employed in
making the solution:-Zinc sulphate thirty five ounces; iron sulphate, twelve
ounces; but we do not limit ourselves to these proportions nor to using the pure
salts, as for instance the dross formed in hot galvanizing baths, or the "sick
spent solution from sulphuric acid pickling tanks, can be used or the sulphate of
iron can be crystallized from it for use in the electrolyte. Iron sulphate as found
in commerce is a ferrous salt but we find it advantageous to partially convert it
ferric salt which may be done by means of atmospheric air or oxygen or
romate of potash or any other suitable oxidizing agent. This oxidizing treat-
t may be applied to the iron sulphate before or after it is added to the sulphate
inc. The solution or electrolyte, is preferably used with zinc dust or zinc in a
finely divided form, suspended in the solution, or electrolyte and kept suspended
therein by any suitable means or placed at the bottom of the tank, or cell and
stirred up at intervals; but where very smooth coatings are desired it is preferred
to regenerate the solution, or electrolyte, by passing it into a separate vessel
and there dispersing through it, by mechanical agitation, fire heat, or other means,
zinc dust, or finely divided zinc, so as to reconvert into sulphate of zinc, the acid
which has been formed by reason of the deposit of zinc from the solution or
electrolyte, in the process of electro-deposition. The anodes may be of any
suitable material, for instance the zinc ore from which zinc is to be obtained or
where the zinc dust, or finely divided zine is used as described, they can be of iron
or lead. Or the anode may be made according to this invention from zine dust, or
zinc or zinc compound in a divided condition and formed into a coherent mass by
means of zinc sulphate, or other means of causing the divided zinc or zinc compound
to cohere. The material thus prepared may if necessary be supported in or upon
any suitable frame or container.
In some cases we find it advantageous to dip the articles to be zinced in a
solution of bichromate of potash and then dry them in an oven or on a sand bath
before placing them in the zincing bath.
Dated this 11th day of February 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.

page_text: Improvements in and Means to be Employed for the Obtainment of
Zinc from its Ores, and the Electro-deposition of Zinc upon
Iron or other Metals or Alloys.
We, THE COWPER-COLES GALVANIZING SYNDICATE LIMITED of 39 Victoria
Street, in the City of Westminster and SHERARD OSBORN COWPER-COLES of
16 Adam Street Manchester Square in the County of London Engineer 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:—
This invention relates to the obtainment of zinc from its ores, and the electro-
deposition of zinc upon iron, or other metals, or alloys; and has for one of its
objects to provide means whereby a good, bright, and thick deposit of zinc can
be obtained in an efficient manner, without the formation of zinc sponge. There
is employed according to this invention in the depositing tank or cell, an electro-
lyte, or solution, composed of zinc sulphate to which is added iron sulphate as
hereinafter more particularly explained. Excellent bright deposits of zinc upon
iron cau, for example, be obtained by using the following proportions of the con-
stituents to each gallon of water employed in making the solution :-Zine
sulphate, thirty-five ounces, and iron sulphate, twelve ounces, but we do not
limit ourselves to these proportions, nor to using the pure salts, as for instance,
the dross formed in hot galvanizing baths, or the "sick," or spent, solution from
sulphuric acid pickling tanks, can be used, or the sulphate of iron can be
crystallized from it for use in the electrolyte. Iron sulphate as found in commerce
is a ferrous salt, but we find it advantageous to partially convert it into ferric
salt which may be done by means of atmospheric air, or oxygen, or ozone, or
bichromate of potash, or any other suitable oxidizing agent. This oxidizing
treatment may be applied to the iron sulphate before, or after, it is added to the
sulphate of zinc. The solution, or electrolyte, is preferably used with zine dust,
or zinc in a finely divided condition, suspended in the solution, or electrolyte, and
kept suspended therein by any suitable means, or placed at the bottom of the
tank, or cell, and stirred up at intervals; but where very smooth coatings are
desired it is preferred to regenerate the solution, or electrolyte, by passing it into
a separate vessel and there dispersing through it, by mechanical agitation, fire heat,
or other means, zinc dust, or finely divided zinc, so as to reconvert into sulphate
of zinc acid which has been formed by reason of the deposit of zinc from the
solution, or electrolyte, in the process of electro-deposition. If the quantity of
sulphate of iron in the electrolyte should fall short of the quantity required to
maintain the brightness of the deposit, a further quantity of iron salt can be added
to the electrolyte, or any oxide of iron produced in the regenerating vat can be
dissolved by sulphuric acid of any desired strength and the solution so formed be
added to the electrolyte. The anodes may be of any suitable material, for instance
they may be formed from the zinc ore from which zinc is to be obtained, or, where
the zinc dust, or finely divided zinc is used as described, they can be of iron, or
lead, or other suitable insoluble material. Or the anode may be made according
to this invention, from zinc dust, or zinc, or a basic salt of zinc, or oxide of zinc,
formed into a coherent or compact mass by means of zinc sulphate, or sal-ammoniac,
or other means of causing the divided zinc, or zinc compound, to form such a
coherent or compact mass suitable to constitute an anode. The material thus
prepared may, if necessary, be supported in, or upon, any suitable frame, or
container.
.In some cases we find it advantageous to cover the articles to be zinced with an

page_text: adherent coating of oxide which may be done by dipping them in a solution
of bichromate of potash, or other suitable oxidizing agent, and then drying them
in an oven, or on a sand bath, before placing them in the zincing bath.
The electrolytic oxygen, liberated when the zinc is deposited, prevents the
formation of hydrogen compounds of zinc and consequently of zinc sponge. By
the electrolytic oxygen liberated at the anode the sulphate of iron which is added
to the solution is oxidized to the ferric condition at the anode and reduced to the
ferrous condition at the cathode by the hydrogen formed. The action is thus a
continuous one and utilizes the oxygen evolved at the anode.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In the electrolytic obtainment of zinc from its ores and the deposition of zinc
upon iron, or other metals, or alloys, the employment of an electrolyte consisting
of, or containing, zinc sulphate and iron sulphate, converted or partially converted
to the ferric condition and containing also zine dust, or zinc in a finely divided
state, suspended, or stirred, in the electrolyte, substantially as hereinbefore
described.
2. For the purpose described the employment with an electrolyte consisting of,
or containing, zinc sulphate and iron sulphate converted or partially converted to
the ferric condition, of means for passing the electrolyte into a separate vessel,
and thence back to the electrolytic cell, and revivifying the solution, in the said
separate vessel, by means of zinc dust, or finely divided zinc, with, or without, the
addition of zinc sulphate, substantially as herein before described.
3. In combination with the subject matter of either of the preceding claiming
clauses, the employment of an anode made from zine ore, or of zinc dust, or the
like, or a basic salt of zinc, or zinc oxide, made into a coherent, or compact, mass,
substantially as hereinbefore described.
4. For the purpose described the employment in the electrolytic vat of an
anode made of zinc dust or the like or a basic salt of zinc, or zinc oxide, compacted
into a coherent mass, substantially as hereinbefore described.
Dated this 11th day of December 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.