IMPROVEMENTS IN THE METHOD OF TREATING ZINC ALLOYS FOR THE PURPOSE OF RECOVERING THE ZINC THEREFROM.
Year: 1873

page_text: LETTERS PATENT to James Wright, of No. 156, Gresham House,.
Old Broad Street, City of London, Civil Engineer, for the Invention
of "IMPROVEMENTS IN THE METHOD OF TREATING ZINC ALLOYS FOR THE
PURPOSE OF RECOVERING THE ZINC THEREFROM.”. A communication from
abroad by Mariano Guillam
11
PROVISIONAL SPECIFICATION left by the said James Wright at the
Office of the Commissioners of Patents, with his Petition, on the
21st August 1873.
I, JAMES WRIGHT, of No. 156, Gresham House, Old Broad Street,
City of London, Civil Engineer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE METHOD OF TREATING ZINC ALLOYS
FOR THE PURPOSE OF RECOVERING THE ZINC THEREFROM," to be as follows:-
My Invention relates to improvements in the method of recovering
zinc which has been used for desilvering or separating other metals,
chiefly those of lead.

page_text: Hitherto in desilvering lead when zinc is used after melting the
supernatcnt liquid metal which floats on the top is an alloy composed
of lead, silver, and zinc, the great mass in the bottom of the melting
pot being the lead deprived of its silver. The alloy is then put in the
reverberating furnace and the zinc is separated, forming an oxide, which
is then deoxidised and again ready for use. The process of oxidation.
and deoxidation causes a very considerable loss, and the object of my
Invention is to avoid this loss in the zinc.
I have discovered that when an alloy having zinc as an ingredient
is submitted in a closed dry crucible to a white heat the zinc volatilises
and passes over without oxidation in a pure metallic state; to carry
out this I arrange in a furnace one or more crucibles or melting pots,
into which the alloy containing the zinc is placed, a tube passes from
cach of the crucibles and connects it with a closed receiver; the mouth
of the crucible being then closed, and the pipe connexions with the
crucible and receiver, as well as the crucible mouth, being luted or
hermetically closed, the whole resembling a still or alembic. The
furnace being then brought into action upon a white heat being
obtained the zinc volatilises and passes through the pipe and is deposited
in the receiver in a metallic state, by which process a great saving is
effected.
I claim the application of my Invention to all processes when it is
11
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said James Wright in the Great Seal Patent Office 2
on the 20th February 1874.
•
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
WRIGHT, of No. 156, Gresham House, Old, Broad Street, City of
London, Civil Engineer, send greeting.
0
.
WHEREAS Hei most Excellent Majesty Queen Victoria, by Her 3
Letters Patent, bearing date the Twenty-first day of August, in the
year of our Lord One thousand eight hundred and seventy-three, in
the thirty-seventh year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said James Wright, Her special
licenco that I, the said James Wright, my executors, administrators, 3

page_text: and assigns, or such others as I, the said James Wright, my
executors, administrators, and assigns, should at any time agree with
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
5 exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE METHOD OF TREATING ZING ALLOYS FOR THE PURPOSE
OF RECOVERING THE ZINC THEREFROM," (a communication to me from abroad
by Mariano Guillem, of Marseilles, France), upon the condition
0 (amongst others) that I, the said James Wright, my executors or
administrators, by an instrument in writing under my, or their,.or
one of their hands and scals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
5 Scal Patent Office within six calendar months next and immediately.
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Wright, do hereby declare,
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
> following statement, that is to say :—
Hitherto in all the different processes for desilverizing lead the
method adopted for recovering the zinc which has been used for
separating the silver is most unprofitable, in so far that by its complete
oxidization it is both diminished in quantity and value.
The object of my Invention is to avoid this oxidization, deterioration,
and loss of the zinc so used, and by a method and means, herein-after
described, to recover the same in a practically pure metallic state.
In order to understand the peculiar application of my system and
Invention I will briefly describe the present way in which zinc is used
in the desilverization of lead, and so far as is necessary indicating the
course of the operations; showing how my Invention is intended to
act and the point in the operations where it is to be introduced.
C
The processes of desilverization are,-
1st. The argentiferous lead having been put into the first of the
large melting pots or crucibles is then mixed with the requisite
quantity.of.zinc.to. attract the silver, which then collects on. the surface

page_text: of the pot, as a compound of lead, zinc, and silver (zinciferous silver.
lead). The scummings or supernatant layers are then removed to the,
concentrating pots or crucibles, and being remolted a great part of the:
lead is precipitated or falls to the bottom of the pot, the upper layers
of the liquid compound consisting mainly of metallic silver in com-
bination with zinc, and of course a diminished amount of lead. The
last process may be again and again repeated, the lead continually.
falling to the bottom, and the supernatant layers containing less and
less, or being more and more pure combinations of silver and zinc.
On the concentration being completed the remaining process is to.
separate the silver from the zine, and here it is that I propose to apply.
my Invention. Hitherto this has been done in several ways cither by
oxidization by the reverberating or other furnace, or by open vola-
tilization, or by chlorization; by all of these processes the action upon:
the zinc is to set it free in such a state as to be greatly diminished in
quantity and value.
My Invention consists in distilling or volatilizing the resulting
compound of zinciferous silver when taken finally from the con-
centrating crucibles in such a manner that the zinc is collected without
oxidization and in a practically metallic state.
In order to illustrate my process I append the accompanying
Drawings, which are intended to shew in a general way the method
and means I use to carry out my Invention, modifications of those will
of course be adopted according to the peculiar circumstances of each
case and of the alloy or compound to be acted upon.
.
Figure 1 is a transverse section, and Figure 2 a plan of a hermetically.
closed crucible set in a furnace. The crucible may be of metal or of
clay, such as would be sufficiently refrangible to withstand the fire;
it consists of 3 parts, the main body of the pot E, the cover C, and
the pipet; these are all luted, so as to seal it hermetically; the pipe
passes into the receiver or condenser F, which also consists of the
bodyf, f, being formed in the shape of a truncated cone, the top 9,
and the bottom h, the whole luted with clay; the body is furnished
with a hole to receive the pipe t, and serves also to draw off the heated
air.
The concentrated scummings or supernatant liquid, consisting mainly
of zinc and silver, are deposited within the crucible, which is then closed

page_text: hermetically, the pipe inserted within the condenser F, which is also
closed, the air being quite dry, the furnace raises the mixture to a white
heat, and in this state the zinc is separated from the silver and distills
or volatilizes over and through the pipe, where it is received and con-
densed in a pure metallic state; when cooled the resulting metals
· may be removed from the respective vessels. .
Having now described the nature of my Invention, and shown the
method and means by which I carry out the same, I wish it understood
that which I claim, and wish secured to me by the before in part recited
Letters Patent is, the recovery of the zinc used in the process of
desilvering lead by means of distillation or sublimation in a close
vessel, so that the said zinc is obtained in a practically pure metallic
state by means of the apparatus and by the process here-within described
and set forth, and I also claim the application of the said process and
means to similar operations in metallurgy.
In witness whereof, I, the aforesaid James Wright, have hereunto set
my hand and seal, this Twentieth day of February, One thousand
eight hundred and seventy-four.