An Improved Process for the Recovery of Perchloride of Iron from the Solutions of Perchloride of Iron used for Etching Purposes.
Year: 1897

page_text: Date of Application; 7th Aug., 1897
Complete Specification Left, 6th May, 1898-Accepted, 11th June; 1898
An Improved Process for the Recovery of Perchloride of Iron from
the Solutions of Perchloride of Iron used for Etching Purposes.
"
I, OTTO LUPPE, of 102, Aeussere Wienerstrasse, Munich, in the Empire of
Germany, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
The use of a solution of perchloride of iron for metallic etching on copper and
its alloys is found preferable to that of acids from a sanitary point of view as no
deleterious gases are evolved by its use.
In order to render the same from an economical point of view at least equivalent
to acids, the following process is employed which constitutes the present invention.
When used for etching purposes the perchloride of iron is partially converted
into protochloride of iron and the solution used for etching is thereby rendered
useless. Pieces of iron are placed in this solution by which means 1st the per-
chloride of iron still present is converted into protochloride and 2nd the copper
which has passed into the solution is precipitated as a valuable bi-product.
The protochloride of iron obtained as a main product is then treated with hydro-
chloric acid and chlorate of potash by which means in a very short time and
without the use of heat or the evolution of deleterious gases, it is converted into
perchloride and is then capable of being again used for metal etching.
Any other suitable substance evolving chlorine may be used in place of hydro-
chloric acid.
An Improved Process for the Recovery of Perchloride of Iron from
the Solutions of Perchloride of Iron used for Etching Purposes.
I, OTTO LUPPE, of 102, Aeussere Wienerstrasse, Munich, in the Empire of
Germany, Manufacturer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement: -
The use of a solution of perchloride of iron for metallic etching on copper and
its alloys is found preferable to that of acids from a sanitary point of view as no
deleterious gases are evolved by its use.

page_text: In order to render the same from an economical point of view at least equivalent
to acids, the following process is employed which constitutes the present invention.
When used for etching purposes the perchloride of iron is partially converted
into protochloride of iron and the solution used for etching is thereby rendered
useless. Pieces of iron are placed in this solution by which means (1st) the per-
chloride of iron still present is converted into protochloride and (2nd) the copper
which has passed into the solution is precipitated as a valuable by-product.
The protochloride of iron obtained as a main product is then treated with hydro-
chloric acid and chlorate of potash by which means in a very short time and
without the use of heat or the evolution of deleterious gases, it is converted into
perchloride and is then capable of being again used for metal etching.
Any other suitable substance evolving chlorine may be used in place of hydro-
chloric acid.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
$
A process for the regeneration of the solution of perchloride of iron employed
in etching metals, characterized by the still existing perchloride of iron being
converted by the addition of pieces of iron into protochloride, and by the metal,
for instance copper, dissolved during the etching being deposited as a by-product,
after which the solution is treated with hydrochloric acid and chlorate of potash
or other suitable substances evolving chlorine, by which means the chloride is
converted into perchloride without the use of heat and without the development
of deleterious gases and the liquid is again rendered suitable for etching purposes,
substantially as herein before set forth."
Dated this 5th day of Mo 1808
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.