Improvements in Apparatus for the Reduction of Argentiferous or other Zinc Ores.
Year: 1890

page_text: Date of Application, 9th Apr., 1890
Complete Specification Left, 2nd Oct., 1890-Accepted, 22nd Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for the Reduction of Argentiferous or
other Zinc Ores.
I, Dr. OCTAVIUS LUMAGHI of 2612, Locust Street, St. Louis, in the State of
Missouri, United States of America, do hereby declare the nature of this invention to
be as follows:-
This invention has for its object mainly to provide an improved means for obtaining
the spelter separate from the lead silver and gold, for obtaining oxide of zinc, and for
the saving of a large percentage of the silver and gold, which, when ores such as are
under consideration are treated in contact with the atmosphere, are liable to be
carried off with the oxide of zinc and other volatile metals.
My improvement is, in part, based upon the familiar construction known as the
Belgian zinc furnace, in that the retorts employed are arranged and heated as in that
type of furnace, and it may also be considered as an improvement upon, or as related
to, the zinc smelting furnace upon which Letters Patent of the United States
No. 196,369 were granted to me on October 23rd 1877, in that the upper end of the
retorts is adapted to be opened to provide for an air draught.
The essential elements of the improved construction are: first, the furnace walls,
fire place and flues, are constructed so that the retorts can be held and have heat
applied to them, substantially as in the same manner as in the Belgian zinc furnace ;
second, in place of applying the condenser to the lower or charging end of the
retort, it is applied to the upper end of the retort; third, the retorts while
substantially similar to those of the Belgian zinc furnace, and adapted to be charged
at the lower end, are perforated at the upper end to provide for the escape thereat
of the gases generated from the contents of the retort; fourth, the manner of
combining the retorts and the condensers so that the zinc vapors shall be readily
condensed in the latter and when condensed, the spelter shall not flow back again
to the retorts; fifth, the means for closing the charging end of the retorts; sixth, the
novel manner of constructing that wall of the furnace where the condensers are
applied; seventh, the means for promoting the formation of oxide of zinc and its
collection.
To fully carry out the improvement, all of the elements above enumerated are needed
in conjunction, but certain portions of the work can be accomplished with but a portion
of them.
The furnaces are arranged in combination opposite each other with a sufficient space
between them to permit of the operatives attending to the condensers, said space being
roofed in and provided with end walls and doors at each side thereof, so that it can be
so enclosed to form a chamber sufficiently tight to receive the gases escaping from the
retorts to the condensers, and enable them by means of an exhaust flue to be withdrawn
from said chamber and collected in some suitable receptacle for receiving and collecting
the oxide of zinc. The furnaces may be used singly and the gases be exhausted by
the flue.
The furnaces are each constructed with a fire-place, front wall, back wall, roof, side
walls, supports for the lower and upper ends of the retorts, all substantially similar to
the Belgian zinc furnace, except that the back wall is perforated to admit the condensers,
which project through said wall.
The retorts so far as their size, general form and composition are concerned, resemble
those employed in the furnace just above mentioned. They are adapted to be charged
through an opening at the lower end, closed by a stopper, which is in the form of a
lisc, having notches in its periphery at equal distances from each other, and when the
stopper is placed in said opening one of the notches is at the bottom of the same and

page_text: the others somewhat above the centre of the retort. The upper end of the retort is
closed except that it has a central perforation about two inches in diameter.
The condensers are of the usual form. They are connected to the retort and
inclined forward and so adjusted in accordance with the inclination of the retort, that
a considerable portion of its interior is below the level of the perforation in the retort
head; thus owing to the position of the retort and condenser, both inclining downward
from their point of union, the distilled zinc gathered in the condenser cannot flow
back into the retort, and any lead or other metal that may have become liquified
during distillation can not reach the distilled zine in the condenser, but will find
its way to the lower end of the retort, where it may be recovered by tapping the
lowest notch of the stopper.
An additional feature of this part of the construction is, that the perforation in
the head of the retort, being only about one-third the inside diameter of the retort,
the gases generated therein are reduced in volume-that is, concentrated-in passing
through said perforation, the velocity of the current of the gases being also
proportionally increased, and thus the gases reach the condenser in the shape of a jet
of concentrated zinc vapor, which coming through the perforation in a straight line
strikes upon a limited area of the condenser at its upper, inner side, such impact being
proportioned to the increased velocity of the current of zinc vapor.
The cooler temperature of the inside of the condenser as compared to that in the
retort, together with the increased impact consequent upon the increased velocity of
the current of zinc vapor as it strikes the cooler surface of the condenser, causes
the complete condensation of the vapor into liquid metal, and avoids the formation
of zinc powder, which is the result of a too slow supply of zinc vapor.
Another feature of this invention is in the constructing of a dam for the condenser
out of material from the charge mixed with blue powder and which is placed inside
the smaller end of the condenser, as is usual in the art to which this invention belongs,
to regulate the flame and hold the spelter temporarily so that, the condenser being
properly inclined and adjusted, the highest point of the dam will be somewhat lower
than the lower margin of the perforation in the retort head and the distilled zinc
not flow back into the retort when suffered to remain in the condenser until it
overflows. Another feature is a circular groove which is formed in the upper end of
the retort. This groove in diameter disagrees with that of the end of the condenser,
the object being to provide a ready means for ensuring the proper relation of the
condenser and retort. For, however the retort or the condenser may be turned
around, the end of the condenser can enter the groove at one point only and at
other points is excluded therefrom and as that one point is naturally the lowest
point, the condenser however hastily it is adjusted will always assume the proper
inclination for effecting the above results.
The operation is as follows:-The retorts are placed in position in the furnace and
charged with the ores and other material, closed with the stopper and lnted, and the
furnace is fired, all in the customary manner. The condensers are applied as described
and the joint between the condenser and retort, and the spaces in the front and back
walls of the furnace around the retorts, luted. That portion of the zinc which is to
form spelter is distilled through the perforation in the retort, into the condenser where
it is condensed, the operation being hastened by reason of the gaseous current being
caused to encounter the upper inner side of the condenser. A small opening is left
above the dam in the outer end of the condenser for the usual flame to be burned
at that point as is customary. The spelter can be withdrawn from the condenser
in any suitable manner, and the liquefied lead and silver (if any) can be extracted
from the retort by tapping the lowest notch in the stopper. The contents of the
retort can be reached with a poker, as, for instance, when it is desired to scrape
the shell of the retort to separate therefrom anything which may collect upon it,
by introducing the poker at one of the upper notches in the stopper. When the
spelter has been obtained and that stage of the operation has arrived at which the
remaining zinc is to be recovered in the form of an oxide, one of the upper notches in
the stopper is opened to admit the outer air which then passes into and through the

page_text: retort and then through the condenser, in its route coming in contact with the ores
and forming oxide of zinc. From the condenser the gaseous current passes out into the
space between the furnaces whence it passes out at the flue. Any suitable means, such
as an exhaust fan, may be used to promote the movement of the air into the retorts
and the discharge and delivery of oxide of zine into the flue. While this is going on
the doors of the space are closed. Such silver and gold as passes off with the current
of oxide of zinc is carried along with it out at the flue and is ultimately collected with
such oxide.
Thus, by the same means and, if desired, without changing any part thereof, all of
the above described operations are carried on; the spelter is separately collected; the
lead and such silver as liquefies are collected by themselves; the zinc oxide is formed
and obtained; and the volatilized precious metal is saved. It may be added that the
ore material remaining within the retort has, in effect, by reason of the heating to.
which it has been subjected, been roasted, and thus made ready for subsequent
treatment elsewhere and according to any of the well-known methods for the recovery
of gold and silver.
Any suitable means, such as fragments of bricks, or of retorts, carefully luted, may
be used to close the lower end of the retorts, instead of the stopper, provided a proper
opening in said stopper is formed. The stopper is provided with an opening to receive
a handle in manipulating the same, which opening is luted when the stopper is in
place and should be slightly above the centre of the stopper so that on being
manipulated by the handle one of the notches in the periphery of the stopper will
necessarily come to the lower side of the head of the retort.
O. LUMAGHI.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.
Con mac si no
COMPLETE SPECIFICATION.,
Improvements in Apparatus for the Reduction of Argentiferous or
other Zinc Ores."
I, Dr. OCTAVIUS LUMAGHI of 2612 Locust Street, St. Louis, in the State of
Missouri, United States of America, 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 :-
This invention has for its object, mainly to provide an improved means for
obtaining the spelter separate from the lead, silver, and gold; for obtaining oxide
of zine; and for the saving of a large percentage of the silver and gold which,
when ores such as are under consideration are treated in contact with the atmosphere,
are liable to be carried off with the oxide of zinc and other volatile matters.
My improvement is in part based upon the familiar construction known as the
Belgian zinc furnace, in that the retorts employed are arranged and heated as in
that type of furnace, and it may also be considered as an improvement upon, or as
related to, the zinc-smelting furnace upon which Letters Patent of the United States,
No. 196,369 were granted to me on October 23rd 1877, in that the ends of the
retorts are adapted to be opened to provide for an air draft.
The essential elements of the improved construction are: first, the furnace walls
fireplace and flues are constructed so that the retorts can be held and have heat
applied to them substantially in the same manner as in the Belgian zinc furnace;
second, in place of applying the condenser to the lower or charging end of the
retort it is applied to the upper end of the retort; third, the retorts, while
substantially similar to those of the Belgian zinc furnace and adapted to be charged
at the lower end, are perforated at the upper end to provide for the escape thereat
of the gases generated from the contents of the retort; fourth, the manner of
combining the retorts and the condensers so that the zinc vapors shall be readily

page_text: condensed in the latter and when condensed the spelter shall not flow back again
to the retorts; fifth, the means for closing the charging end of the retorts; sixth,
the novel manner of constructing that wall of the furnace where the condensers are
applied seventh, the means for promoting the formation of oxide of zinc and its
collection.
To fully carry out the improvement all of the elements above enumerated are
needed in conjunction, but certain portions of the work can be accomplished with
but a portion of them as will appear from the following detailed description of the
apparatus and its operation, reference being had to the accompanying drawing,
forming a part of this Specification, in which
Figure 1 is a vertical cross-section of the apparatus.
Figure 2 is a perspective view of one of the retorts with a condenser attached
thereto, looking upwards towards the condenser and the upper end of the retort.
Figure 3 is a perspective view of the condenser and the upper portion of the retort,
looking sidewise thereat; and
Figure 4 is a vertical longitudinal section of the retort and condenser, the stopper
used to close the lower or charging end of the retort being shewn detached and in
front elevation.
Similar letters of reference denote similar parts in all the views.
A and A' represent the furnaces of the preferred construction arranged in com-
bination opposite each other with a sufficient space R between them to permit of the
operatives attending to the condensers, said space being provided with a roof C, end
walls D D, and doors d d at each side thereof so that it can be so enclosed as to
form a chamber sufficiently tight to receive the gases escaping from the retorts to
the condensers and enable them, by means of an exhaust flue E, to be withdrawn
from said chamber and collected in some suitable receptacle (not shewn) for receiving
and collecting the oxide of zinc. The furnaces may be used singly and the gases
be exhausted by the flue E.
The furnaces are each constructed with a fire-place a, front wall a¹, back wall a²,
roof a³, side walls a', supports a³ for the lower ends of the retorts, and supports
for the upper ends of the retorts; all of which elements are substantially as in the
Belgian zine furnace except that the back wall a² is perforated to admit the con-
densers which project through said wall, as shewn in Figure 1.
BB are the retorts which, so far as their size, general form, and composition, are
concerned, resemble those employed in the furnace just above mentioned. They are
adapted to be charged through an opening in their lower end and said opening is
closed by a stopper & which is in the form of a disc having notches 63 in its
periphery at equal distances from each other and when the stopper is placed in said
opening one of said notches is at the bottom of the same and the others somewhat
above the centre of the retort. The upper end 63 of the retort is closed except that
it has a central perforation about two inches in diameter.
C is one of the condensers, which is of the usual form and is connected to the
retort, inclined forward and so adjusted in accordance to the inclination of the retort
that a considerable portion of its interior is below the level of the perforation 64 in
the retort head; thus, owing to the position of the retort and condenser, both
inclining downward from their point of union, the distilled zinc gathered in the
condenser cannot flow back into the retort and any lead or other metal that may
have become liquefied during distillation cannot reach the distilled zinc in the
condenser but will find its way to the lower end of the retort where it may be
recovered by tapping the lowest notch of the stopper 61.
An additional feature of this part of the construction. is that the perforation b
being only about one-third the inside diameter of the retort the gases generated
therein are reduced in volume-that is, concentrated-in passing through the
perforation, the velocity of the current of the gases being also proportionally
increased, and thus the gases reach the condenser in the shape of a jet of concentrated
zinc vapor which coming through the perforation 61 in a straight line strikes upon a
limited area of the condenser at its upper, inner side such impact being proportioned

page_text: to the increased velocity of the current of zinc vapor, as indicated by the dotted
line in Figure 4. The cooler temperature of the inside of the condenser, as
compared to that in the retort, together with the increased impact consequent upon
the increased velocity of the current of zinc vapor as it strikes the cooler surface of
the condenser causes the complete condensation of the zine vapor into liquid metal,
and avoids the formation of zinc powder which is the result of a too-slow supply of
zinc vapor.
Another feature of this invention is in the construction of the dam c² for the
condenser out of material from the charge mixed with blue powder and which is
placed inside the smaller end of the condenser as is usual in the art to which this
invention belongs, to regulate the flame and hold the spelter temporarily so that, the
condenser being properly inclined and adjusted, the highest point of the dain will be
somewhat lower than the lower margin of the perforation in the retort and the
distilled zinc e cannot flow back into the retort when suffered to remain in the
condenser until it overflows.
Another feature is, forming a circular groove 6 in the upper end of the retort
which in diameter disagrees with that of the end c of the condenser, the object being
to provide a ready means for ensuring the proper relation of the condenser and
retort. For however the retort or the condenser may be turned around, the end c
of the condenser can enter the groove at one point only and at other points is
excluded therefrom and as that one point is naturally the lowest point, the condenser,
however hastily it is adjusted will always assume the proper inclination for effecting
the above results.
The operation is as follows:-The retorts are placed in position in the furnace, as
shewn in Figure 1, and duly charged with the ores and other material, closed with
the stopper and luted, and the furnace is fired, all in the customary manner.
The
condensers are applied as described, and the joint between the condenser and retort,
and the spaces in the front and back walls of the furnace around the retorts, luted.
That portion of the zine which is to forin spelter is distilled through the perforation b
in the retort into the condenser where it is condensed, the operation being hastened
by reason of the gaseous current being caused to encounter the upper inner side of
the condenser, as indicated by the dotted line x in Figure 4. A small opening c³ is
left above the dam in the outer end of the condenser for the usual flame to be burned
at that point, as is customary. Owing to the position of the condenser and its
relation to the perforation in the retort, the liquefied spelter cannot flow back into
the retort and such lead and silver as may liquefy in the retort cannot enter the
condenser. The spelter can be withdrawn from the condenser in any suitable
manner and the liquefied lead and silver (if any) can be extracted from the retort
by tapping the lowest notch in the stopper 6. The contents of the retort can be
reached with a poker, as, for instance, when it is desired to scrape the shell of the
retort to separate therefrom anything which may collect upon it, by introducing the
poker at one of the upper notches in the stopper 6. When the spelter has been
obtained and that stage of the operation has arrived at which the remaining zinc is
to be recovered in the form of an oxide, one of the upper notches in the stopper b¹
is opened to admit the outer air which then passes into and through the retort and
then through the condenser, in its route coming in contact with the ores and forming
oxide of zinc. From the condenser the gaseous current passes out into the space
whence it passes out at the flue E. Any suitable means, such as an exhaust fan (not
shewn) may be used to promote the movement of the air into the retorts and the
discharge and delivery of oxide of zinc into the flue. While this is going on, the
doors of the space R are closed. Such silver and gold as passes off with the current
of oxide of zinc is carried along with it out at the flue E and is ultimately collected
with such oxide.
Ꭱ
Thus by the same means, and, if desired, without changing any part thereof, all of
the above described operations are carried on; the spelter is separately collected; the
lead, and such silver as liquefies, are collected by themselves; the zinc oxide is
formed and obtained; and the volatilized precious metal is saved. It may be added

page_text: that the ore material remaining within the retort has, in effect, by reason of the
heating to which it has been subjected, been roasted and thus made ready for subse
quent treatment elsewhere and according to any of the well known methods for the
recovery of gold and silver.
The roof to the space enclosed at the back of the furnace may have the shape
indicated by the dotted line y in Figure 1. Any suitable means, such as fragments
of bricks or of retorts carefully luted, may be used to close the lower end of the
retorts, instead of the stopper 6, provided an opening, corresponding with that 64, in
said stopper is formed. The opening 66 shewn in the stopper is merely to receive a
handle in manipulating the same, is luted when the stopper is in place, and should
be slightly above the centre of the stopper so that on being manipulated by the
handle one of the notches 62 will necessarily come to the lower side of the head of
the retort.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, declare that what I
claim is ;
1. The combination, with a furnace having openings in its front and back walls, of
an enclosure at the rear of the furnace having a tight roof and doors and connected
with a suction device, retorts resting in said openings in the furnace walls and having
their butt ends perforated, and condensers applied to the butt ends of the retorts,
substantially as shewn and described.
2. The combination, with a retort having a central perforation in its upper end and
an annular groove surrounding said perforation and closed at its lower end by a
removable stopper, of a condenser applied to the upper end of the retort and the
groove therein, the upper end of the condenser having a diameter different from that
of said groove substantially as shewn and described.
3. The combination, with a retort, of a stopper adapted to he inserted and luted
in the lower end of the retort, said stopper being in the shape of a disc having a
series of equi-distant notches in its periphery and an opening slightly above its
centre, the latter adapted to receive a handle whereby said disc may be manipulated
to bring one of said notches at or near the bottom of the lower end of the retort,
substantially as shewn and described.
Dated this 2nd day of October 1890.