IMPROVED PROCESS OF SEPARATING PRECIOUS METALS FROM LEAD AND ZINC AND APPARATUS EMPLOYED THEREFOR
Year: 1870

page_text: LETTERS PATENT to George Haseltine, of the "International Patent
Office," Southampton Buildings, London, for the Invention of
AN IMPROVED PROCESS OF SEPARATING PRECIOUS METALS FROM LEAD AND
ZINC AND APPARATUS EMPLOYED THEREFOR."-A communication from
abroad by Edward Balbach, junior, of Newark, New Jersey, United
States of America.
Sealed the 20th January 1871, and dated the 3rd December 1870.
COMPLETE SPECIFICATION filed by the said George Haseltine at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 3rd December 1870, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HASELTINE, of the "International Patent Office," Southampton Build-
ings, London, send greeting.
WHEREAS I am in possession of an Invention for "An IMPROVED
PROCESS OF SEPARATING PRECIOUS METALS FROM LEAD AND ZINO, AND APPARATUS
EMPLOYED THEREFOR," and have petitioned Her Majesty to grant unto me,
my executors, administrators, and assigns, Her Royal Letters Patent
for the same, and have made solemn Declaration that it has been com.

page_text: municated to me from abroad by Edward Balbach, junior, of Newark,
New Jersey, United States of America.
NOW KNOW YE, that I, the said George Haseltine, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed, in and by the following
statement, reference being had to the accompanying Drawing forming
a part of this Specification :---
This Invention consists, first, in a cheap and expeditious method of
separating silver or other precious metals from lead, when zinc is used
in the process of separation, by first combining the lead which contains
the silver or other precious metals with zinc, and after the alloy thus
formed has been sufficiently stirred or agitated to cause the zinc to take
up the silver or other precious metals previously contained in the lead,
then subjecting the said alloy to a "sweating" process by heating it in
a furnace with an inclined bottom or hearth to such a degree that the
lead will melt (without however melting the zinc, the silver, and other
precious metals), whereby the largest portion of the lead is caused to
run off leaving the zinc, silver, and other precious metals together with a
small quantity of lead unmelted in the furnace.
The said Invention consists, sceondly, in a moveable black lead retort
up for the
applied in a furnace in such a manner that it can be turned
reception of the alloy of zinc, silver, and other precious metals with
a small quantity of lead, and after the zinc has been distilled and con-
densed in a separate condenser can be readily turned down to discharge
the precious metals with the impurities still remaining mixed with them
to be subsequently refined.
The said Invention consists, thirdly, in combining with a retort a
furnace supported by gudgeons, which have their bearings in stationary
frames or standards, in such a manner that the furnace together with
the retort can be turned and the retort discharged and afterwards re-
charged without distributing any part of the furnace or interrupting

page_text: the furnace hung in gudgeons, and shown in position for discharging
the contents of the retort; Figure 3 is a vertical section of the same
showing the furnace in its upright position; Figure 4 is a similar
section of a modification thereof. Similar letters indicate the same
parts throughout the Drawing.
-
In carrying into practice the first part of my Invention I prepare an alloy
by combining lead containing silver or other precious metals with a suffi-
cient quantity of zinc; this part of the precess may be effected by
melting the lead in a kettle and then adding to it the melted zinc, or by
first melting the zinc in the kettle and adding to it the lead in a fused
state, the lead after having been refined is melted in a low heated furnace
with an inclined hearth and runs thence into the kettle containing the
melted zinc. This process has this advantage the lead leaves some of
its impurities in the furnace, and consequently is still further refined
before it is mixed with the zinc. The mixture is next stirred in the
kettle about fifteen minutes, or until the zino has taken up all the
precious metals from the lead, and then the alloy is cast into pigs of
suitable size. I usually put from 20 to 80 pounds of zinc in the kettle
to melt, I place one ton of lead in the furnace to be melted and mixed
with the zinc, the per-centage of zinc to be used depending upon the
richness of the lead in the precious metals. After the alloy of zinc
with the lead and precious metals has been cast into pigs, the pigs
are placed in a furnace with an inclined hearth and heated sufficiently
to melt the lead, but not enough to melt the zinc or the precious metals,
an operation technically known as "sweating." The largest portion of
the lead is thus caused to run out of the furnace, when it is cast into
pigs to be further refined if necessary into merchantable lead, while
the zinc together with the precious metals and a small quantity of
lead remain on the hearth of the furnace. By this process the lead
is separated from the zinc and precious metals much better and in
less time than by the processes heretofore used for this purpose, in
which the stirring in the kettle is continued for two or three hours,
when the fire is allowed to cool down and the zinc in combination with
the precious metals as the same rise to the surface are skimmed off, the
lead being drawn off afterwards.
After having completed the sweating process I take the dross
remaining on the inclined hearth of the furnace, and consisting chiefly
of zinc mixed with precious metals and a small quantity of lead, and

page_text: introduce the same with some fine coal into the retort d (see Figures 2, 3,
and 4), the said retort being enclosed in the furnace a, which is built up
of brick and provided with a grate b and a bridge or bearer c capable of
supporting the retort and so formed that coal may be packed at its sides
and also at the sides of the retort. To the sides of the furnace a are
secured brackets e, by preference made of cast iron; from each of these
brackets projects a gudgeon f which has its bearings in a standard g
situated one on each side of the furnace and of such a height that the
furnace can be conveniently turned on its gudgeons. From the rear
wall of the furnace projects the smoke flue g¹, and if the said furnace is
brought in an upright position, as in Figure 3, this smoke flue bears
.against the mouth of a flue h leading to the chimney or smoke stack
while the same does not interfere with the operation of swinging the
furnace on its gudgeons as shown in Figure 2. The retort is so arranged
in the furnace that it occupies an upright or upwardly inclined position,
when the furnace is brought in the position shewn in Figure 3, but by
turning the furnace to the position shewn in Figure 2 the retort is
brought into its discharging position. When a flame fire is required the
fire-place may either be attached to the movable furnace, or it may be
separate as shewn in Figure 4, where a¹ represents the movable furnace
and 6 the fire-place which communicates through a flue c¹ with the
furnace, while the flame after having circulated through the said furnace
passes through a flued to the chimney flue ; this furnace is so
constructed that the same on being turned on its gudgeons swings away
from the flue c¹ and chimney flue 7. The position of these flues may
be varied in different ways. By these means the retort can be con-
veniently charged and discharged without disturbing any portion of the
furnace and without the necessity of allowing the furnace to cool down
_after every discharge of the retort. The dross having been introduced
into the retort, can be readily heated to distil off the zinc, leaving the
precious metals with a small quantity of lead in the retort.
This last-named operation may also be accomplished in a retort and
furnace such as is shewn in Figure 1, where a represents the walls of the
furnace, 6 the grate bars, and c a bridge or bearer made narrow, so that
the coal may be packed at the sides of it, and also at the sides of the
retort d which is formed with a neck at one end, and supported by the
bearer c. The front of the furnace is provided with an opening e¹ through
which the neck of the retort projects, and this opening is sufficiently
long to allow the retort to be turned down from the position

page_text: shewn in full lines to that shewn in dotted lines. When the retort is to
be charged and heated the opening e¹ is to be filled up by fire-bricks
introduced beneath the neck of the retort d. When the heat rises to the
required degree the zinc contained in the retort is distilled off and
received in any suitable chamber connected to the neck of the said retort,
and after the zinc has been distilled the space e¹ is opened and the retort
is turned down to pour out the precious metals mixed with the remaining
impurities in the concentrated form in which this process leaves the
same. The fuel is to be supplied through a suitable opening over the
retort, and the products of combustion may be taken from the same place
to a chimney. Two of these retorts may be inserted side by side in the
same fire using one and the same chimney. In practice however I
prefer the furnace supported by gudgeons as shown in Figures 2, 3, and 4,
since in this case the operation of removing bricks from and reinserting
them under the neck of the retort can be dispensed with.
Having thus fully described the said Invention as communicated to
me by my foreign correspondent, and shown how the same may be con-
veniently and advantageously carried into practice, I claim,-
First. The within described process for separating silver or other
precious metals from lead by first combining the lead with zinc and then
subjecting the alloy thus obtained to a "sweating" process substantially
in the manner herein set forth.
Second. The arrangement of a movable blacklead retort formed with
a neck supported by a wall in the furnace substantially as set forth,
the said wall being so constructed that it can be easily removed and
reinserted.
Third. The combination of a furnace supported by gudgeons with a
retort, substantially in the manner herein shown and described.
In witness whereof, I, the said George Haseltine, have hereunto
set my hand and seal, this Second day of December, in the year
of our Lord One thousand eight hundred and seventy.
Witness,
W. J. LOWE.
GEORGE HASELTINE. (L.S.)