Process for Effecting Electrolytic Deposit with Aluminium.
Year: 1890

page_text: Date of Application, 14th June, 1890
Complete Specification Left, 13th Mar., 1891-Accepted, 9th May, 1891
PROVISIONAL SPECIFICATION.
Process for Effecting Electrolytic Deposit with Aluminium.
I, SALO WOHLE, of 27 Burton Crescent, in the County of Middlesex, Chemist,
do hereby declare the nature of this invention to be as follows:-
:-
My invention relates to a process for effecting electrolytic deposit with aluminium
on metals or other suitable cathodes. I prepare the liquid for the electrolytic bath
in the following manner.
First, I dissolve alum in warm water, using say 2 kilos. alum in crystal to
3 kilos. of water, preferably distilled. Secondly, I make a similar solution of about
the same weight of carbonate of potash with the addition of a small quantity, 8 to
10 grammes of carbonate of ammonia. 1 mix the two solutions, causing effervescence
and precipitation. When the effervescence has quite ceased, I separate the pre-
cipitate and carefully wash it with water.
I then form a second solution of alum, about 4 kilos. dissolved in 10 kilos. of warm
water, and add to it 2 kilos. of pure potassium cyanide in solid form. I pour this
second solution over the washed precipitate previously mentioned and boil the
mixture for about half an hour. I then add water about 10 kilos., and about
2 kilos. of potassium cyanide, and again boil the whole for about quarter of an hour.
I filter so as to separate the precipitate from the liquid which is then ready for use
in the electrolytic bath. It is to be understood that, although I have stated
quantities of the materials employed, I give these proportions by way of example
of what I find practically serviceable, but these proportions may be somewhat
varied according as the qualities of the materials employed may themselves vary.
With the liquid produced as above described I charge the electrolytic bath in
which I use as anodes perforated plates of aluminium arranged so that they can be
conveniently raised or lowered. I connect these and the cathodes that are to receive
deposit respectively to the terminals of a battery or of a dynamo machine and
transmit an electrical current through the bath, which by preference heat to
about 150° Fahr.
By attaching to the aluminium anodes pieces of other metals, gold, silver, nickel,
copper or the like, the tint of the deposited aluminium can be somewhat varied.
When the aluminium deposited presents its natural grey tint, it may be brightened
by dipping the plated article in a solution of caustic soda which has also the effect
of impeding oxidation.
Dated this 14th day of June 1890.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Process for Effecting Electrolytic Deposit with Aluminium.
I, SALO WOHLE, of 27 Burton Crescent, in the County of Middlesex, Chemist,
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 a process for effecting electrolytic deposit with aluminium
on metals or other suitable cathodes. I prepare the liquid for the electrolytic bath
in the following manner :-First, I dissolve ammonia alum in warm water, using
say 2 kilos. alum to 10 kilos. of water, preferably distilled. Secondly I make a
similar solution of about the same weight of pearl-ash to which may be added a
[Pic |

page_text: small quantity of 8 to 10 grammes of carbonate of ammonia. I mix the two
solutions causing effervescence and precipitation. When the effervescence has
ceased, separate the precipitate and carefully wash it once with water. I then
form a second solution of ammonia alun about 4 kilos. dissolved in 25 kilos. of
warm water, and add to it 2 kilos. of pure potassium cyanide. I pour this second
solution over the washed precipitate previously mentioned and boil the mixture for
about half an hour in a covered iron vessel, preferably jacketted to ensure uni-
formity of heating. I then add water, about 20 kilos., and about 2 more kilos. of
potassium cyanide, and again boil the whole for about a quarter of an hour. I filter
so as to separate the precipitate from the liquid, which is then ready for use in the
electrolytic bath. It is to be understood that although I have stated quantities of
the materials employed, I give these proportions by way of example of what I find
practically serviceable, but these proportions may be somewhat varied according as
the qualities of the materials employed may themselves vary.
With the liquid produced as above described I charge the electrolytic bath in
which use as anodes perforated or slotted plates of aluminium arranged so that
they can be conveniently raised or lowered. I connect these and the cathodes that
are to receive deposit, respectively, to the terminals of a battery or of a dynamo
machine and transmit an electrical current through the bath, which by preference
I heat from about 80° to 150° Fahrenheit.
By attaching to the aluminium anode pieces of other metals, gold, silver, nickel,
copper or the like, the tint of the deposited metal can be somewhat varied. When
the deposit presents a grey tint, it may be brightened by dipping the plated article
in a solution of caustic soda, which has also the effect of impeding oxidation.
Sometimes a bath made as described is not at once fit for the electrolytic action
desired. In such a case the liquid may be poured back on the solid materials
from which it was filtered, and, after several days it may be filtered again for
usc. It is also found that the plating quality of the bath is generally improved
if a piece of aluminium has been put in the liquid as it is boiled to form the
bath as above described.
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 effecting electrolytic deposit with aluminium
on suitable cathodes by preparing as described from alum, pearl-ash and
potassium cyanide the liquid charge for the electrolytic bath, providing the bath
with perforated or slotted aluminium plates as anodes, and subjecting this bath to
electrical action.
Dated this 13th day of March 1891.
ABEL & IMRAY,
Agents for the Applicant.