Process for Recovering Zinc and Alkali from Spent Liquors of Lalande Voltaic Batteries.
Year: 1888

page_text: Date of Application, 4th Feb., 1888
Complete Specification Left, 3rd Nov., 1888
Complete Specification Accepted, 8th Jan., 1889
Process for Recovering Zinc and Alkali from Spent Liquors of
Lalande Voltaic Batteries.
I, HUGH ARCHIBALD FERGUSSON of No. 4 Wilton Street, Grosvenor Place in the
County of Middlesex, Electrician, do hereby declare the nature of this invention to
be as follows
My invention relates to the recovery of zinc and alkali from the spent liquors of
Lalande voltaic batteries.
In these batteries, as is well known, a solution of caustic alkali, such as potash, is
employed as exciting liquid, and zinc as one of the elements. The spent liquor
contains the alkali and a large proportion of zine combined with it in solution. I place
this spent liquor in an insulated vessel in which there are a number of vertical iron
plates and alternating with thein and separated from them by intervals a number of
clean zinc plates which may have their surfacos amalgamated, or for these may be
substituted plates of other metal with amalgamated surfaces. Í connect all the iron
plates to one terminal of a dynamo-electric machine or other electrical generator and
all the other plates to the other terminal so that an electric current passes through the
layers of liquid between the plates. The effect of this is to produce a flocculent deposit
of zinc on the zinc or amalgamated surfaces, which deposit falls off or may be scraped
off and collected at the bottom of the vessel. From time to time I run off a portion
of the liquor at the bottom, this carrying with it the flocculent zinc. I strain off the
liquid by filter pressing and I thus obtain pure metallic zinc. I return the liquid
strained off to the electrising vessel and I continue this process until the liquor is
cleared of zinc and remains as a solution of the caustic alkali.
In cases where the spent liquor contains impurities resulting from the employment
of impure zinc in the battery, the liquor may in the first place be cleared from these
impurities by hanging in a vessel containing it a number of clean zinc plates. The
effect of this is to cause precipitation of most of the impurities, and this action may
be promoted by heat.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Process for Recovering Zinc and Alkali from Spent Liquors of
Lalande Voltaic Batteries.
I, HUGH ARCHIBALD FERGUSSON of No. Wilton Street Grosvenor Place in the
County of Middlesex, Electrician 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 the recovery of zinc and alkali from the spent liquors of
Lalande voltaic batteries.
In these batteries, as is well known, a solution of caustic alkali, such as potash, is
employed as exciting liquid and zinc as one of the elements. The spent liquor
contains the alkali and a large proportion of zinc combined with it in solution. I
place this spent liquor in an insulated vessel in which there are a number of vertical
iron plates and alternating with them and separated from them by intervals a number
of clean zinc plates which may have their surfaces amalgamated or for these may be
substituted plates of other metal with amalgamated surfaces I connect all the iron
plates to one terminal of a dynamo electric machine or other electrical generator and
all the other plates to the other terminal so that an electric current passes through
the layers of liquid between the plates. The effect of this is to produce a flocculent
deposit of zinc on the zinc or amalgamated surfaces, which deposit falls off or may be
scraped off and collected at the bottom of the vessel. From time to time I run off a
portion of the liquor at the bottom, this carrying with it the flocculent zinc, I strain
off the liquid by filter pressing and I thus obtain pure metallic zinc. I return the
liquid strained off to the electrising vessel, and I continue this process until the liquor
is cleared of zinc and remains as a solution of the caustic alkali.
In cases where the spent liquor contains impurities resulting from the employment
of impure zinc, the liquor may in the first place be cleared from these impurities by
hanging in a vessel containing it a number of clean zinc plates. The effect of this
is to cause precipitation of-most of the impurities, and this action may be promoted
by beat.
As the zine deposited in flocculent or spongy form is liable to become oxidated, it
should either at once be solidified by pressure or fusion or if it be retained for any
time in the spongy condition, it should be protected by impregnation with paraffin or
other suitable protective material.

page_text: 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 1
claim is :-
The herein described process for recovering zinc and alkali from spent liquor of
Lalande batteries, by subjecting the liquor to electrolytic action in thin layers between
iron plates and zinc or amalgainated plates, filter pressing the mixture of liquor and
deposited zinc returning the pressed out liquid to the electrolytic bath for further
action and forming the zinc into blocks or ingots by pressure or fusion.
1000
ABEL & IMRAY,
Agents for the Applicant.