AN IMPROVED PROCESS AND APPARATUS FOR OBTAINING ZINC AND COPPER FROM ORES OR OTHER SUBSTANCES A
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine, Lako,
"
& Co Patent Agents, Southampton Buildings London for an Invention of
"AN IMPROVED PROCESS AND APPARATUS FOR OBTAINING ZINC AND COPPER
FROM ORES OR OTHER SUBSTANCES A communication to him from abroad by
Léon Louis Charles Krafft, and John Edward Schischkar, both of Paris,
France
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 11th November 1882.
"J
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London, "AN IMPROVED PROCESS AND APPARATUS FOR
OBTAINING ZINO AND COPPER FROM ORES OR OTHER SUBSTANCES A com-
munication to him from abroad by Léon Louis Charles Krafft, and John Edward
Schischkar, both of Paris, France.
The aqueous solutions of ammoniacal gas and of carbonate of ammonia have the
property of dissolving oxides and carbonates of copper and zinc, and the latter are
precipitated if the ammonia or the carbonate of ammonia is extracted from their
solutions; it is upon the application of this proporty of the ammonia that this
method or process for the treatment of copper and zinc orcs is based.
The two ammoniacal solutions act in the same manner but it is liquid ammonia,
that is to say, ammonia in solution in water, that is referred to in the following
description.
The ammonia only dissolves the oxides and carbonates of copper and zinc in the
ores which naturally contain them, otherwise it is necessary to roast the material
completely several times over with carbon in order to decompose the sulphates,
antimoniates, arsenates and other matters which may be contained therein and
which will occasion great loss in the treatment of the material,
The solution of ammonia of commerce at twenty degrees which contains about
five hundred times its volume of ammoniacal gas, dissolves such a quantity of oxide
and carbonate that the proportion of metal dissolved is 0.13 of its weight, in
practice it is necessary to employ ten parts by weight of liquid ammonia of
commerce to one part by weight of the metal contained in the ore in the form of
oxide or carbonate.
The said invention comprises two principal series of operations, that is to say :-
First, the dissolving of the oxides or carbonates of zinc or copper in the

page_text: ammoniacal liquid the washing and separating of the gangues, and the filtration of
the liquid containing the metal in solution. And second the precipitation of the
dissolved oxides or carbonates by the expulsion of the ammoniacal gas from its
solution, the washing and separation of the said oxides or carbonates, the filtration
and cooling of the liquid still containing a certain quantity of ammonia, and finally
the regeneration of the concentrated ammoniacal liquid designed to be employed
in subsequent operation's.
..
C
In carrying out these two principal operations for the treatment of copper or
zinc ores, I employ special apparatus the arrangement of which varies according to
whether the ammoniacal gas is driven from its solution by the action of heat alone,
or by the action of a vacuum, the heat being applied only to prevent the tem-
perature in the apparatus from falling below from twenty five to thirty degrees.
When a vacuum is employed the arrangement which I prefer necessitates the
use of a powerful air-pump. When heat alone is employed, the heat is furnished
either by means of steam or by the direct application of heat from a furnace as
hereinafter described.
I will describe successively the different arrangements above indicated and
corresponding with the two modes of extracting the ammoniacal gas contained in
the-solutions.
In dissolving oxides or carbonates of zinc or copper in ammonia, I employ the
following arrangement, that is to say:The ore, pulverised and passed through a
No 20 sieve, that is to say, one of which the meshes-are less than one inillimetre, is
brought in a wagon to the top of a mixer. A charged-hopper-is-then opened by
allowing the doors to fall, these doors are again closed. by means of-rods, and the-
contents of the wagon aro emptied into the said hopper, and will servo for the-
succeeding operation and ensure the tightness of the closure.
The said mixer is made of sheet metal-and of cylindrical form, it contains a half
helix or screw blade set in motion by means of a bevel-wheel actuated by a motor;
this screw is designed to agitate and constantly return the ore into the-liquor.
After the introduction of the ore, the volume of ammonia-corresponding with the
weight of the ore is admitted by means of a cock situated at the upper part of the
apparatus the level of the liquid being easily ascertained by a gauge glass; the
operation must be effected at the ambient temperature, any elevation of the
temperaturo diminishing the quantity of ammonical gas dissolved and causing a
useless tension of the gas.
In less than two hours, the dissolution of the oxide or carbonate contained in the
ore is terminated; the agitator is then stopped and the liquid contained in the
apparatus is allowed to settle for about thirty minutes and is then successively
drawn off by three cocks placed at different levels; the ammoniacal solution
strongly agitated flows into a tank or reservoir by means of a pipe.
The sandy residues left in the mixer are still impregnated with ammonia con-
taining metallic oxide in solution; a suitable volume of pure ammoniacal liquid is
then introduced into the apparatus by the aforesaid cock and the agitator is again
set in motion. The liquid is then allowed to settle and drawn off as above
described combined with the liquid previously left in the apparatus.
The sand or pulverulent gangue remains in the apparatus, containing only nearly
pure ammonia which can be recovered; for this purpose a valve is opened and a
certain quantity of water is admitted into the mixer by means of a cock, the
agitator is then set in motion; all the sand, with a certain quantity of water, passes
into a boiler arranged for this purpose a little below the lower level of the mixer.
The said valve and cock are again closed and another series of operations is
commenced. The complete operation occupies two hours or three at the most.
In order to extract the ammonia contained in the sand and in the washing water
in the said boiler, the latter is, by means of a pipe, placed in communication with
a powerful air-pump which effects an energetic exhaustion and at the same time
steam is introduced by means of a pipe; the ammoniacal gas exhausted is driven
into chambers for regenerating the ammoniacal liquid.
"
{
4

page_text: The ammoniacal gas, under a low pressure, or in a partial vacuum, the temperaturo
of the liquid being maintained at twenty five or thirty degrees, is almost entirely
extracted in one hour. The exhaust valve is then closed, as well as the steam
inlet, and a valve and cock are opened, and after removing a manhóle on the boiler
the interior of the same is cleansed of the sand which it contains.
As above stated, the ammoniacal solution charged with zinc in solution, which
passes into the said tank or reservoir, is agitated it is again taken by a rotary
pump and forced through a pressure filter in which the filtering material is asbestos
or wool compressed between two perforated plates, the apparatus being so arranged
that these materials can be replaced with facility.
The lower conical part of the filter is furnished with a rotary shaft set in
motion by means of a belt and pulley which moves a circular brush designed to
constantly cleanse the lower porforated plate of the filter and to detach thorefrom
the sediment, which falls to the bottom of the filter where an agitator keeps it in
suspension so that it can be extracted from time to time by means of a cock.
This filtration would be needless for the cupreous solutions and for the preparation
of oxide of zinc, with a view to the manufacture of this metal; it is on the contrary
indispensable if it is desired to apply the oxide of zinc obtained to the manufacture
of colors.
This operation would be, itself, insufficient for obtaining oxide of zinc absolutely
pure with calamine; in this case, it would be necessary to immerse plates of zinc
for twenty four hours in the filtered ammoniacal liquor which would precipitate
the lead, cadmium, or other matters which might accompany the zine in the
solution.
As above stated, the oxides or carbonates contained in zinc or copper ores can bo
dissolved without employing a vacuum; in this case I employ another arrangement
of apparatus, that is to say-The mixing apparatus is formed of a cylinder of
sheet metal terminated by semi-spherical portions and turning upon two hollow
trunnions one of which receives the driving pulley and the other a pipe passing
through a stuffing box and connected to the pipes for supplying water, ammonia
and compressed air to the apparatus.
Towards the middle of the cylindrical wall of this mixer or receptacle is arranged
a filter between two sheets of metal closed by a tight cover provided with a cock;
on the opposite side of this receptacle is arranged laterally a manhole which serves
for charging the receptacle with ore.
'
The operation is as follows, the proper proportion of ammonia and of the ore to
be treated being employed, that is to say, the ore is first introduced through the
manhole which is then hermetically closed; the requisite quantity of ammonia is
then admitted by the said pipe and the apparatus is rotated. It is stopped after
working for two hours, care being bad to stop the apparatus so that the said filter
is at the under side, to this filter is then fitted a tube whose extremity is flexible, a
cock is then opened to admit compressed air, under the action of which the filtered
solution passes by the said tube into an alembic.
Instead of operating by pressure I can effect the operation equally well by
suction by previously creating a vacuum in the said alembic.
When the said receptacle is emptied the cock is closed, the said tube is dis-
connected and the washing is then proceeded with by admitting a certain
quantity of ammonia and again rotating the said receptacle, it is stopped and the
filtration effected as above described, two washings are thus effected with
ammonia, then one or two with water so as not to leave any metal in the
sediment.
The sediment is emptied out through the man hole which is brought to the
underside of the apparatus into which is admitted a strong current of water and
which is kept in motion during this operation; the waste material extracted by the
water flows into a channel arranged for this purpose below the said apparatus, and
a fresh series of operations can be proceeded with.
In the precipitation of dissolved oxides or carbonates by the extraction of the

page_text: ammoniacal gas contained in the solution when the operation is effected by means
of a vacuum, I adopt the following arrangement of the apparatus that is to say,
the filtered liquor is collected in a tank or vessel and is taken therefrom by a pump
which delivers it into an evaporator. This evaporator, which is made of strong
sheet metal, is provided in its interior with a helical agitator set in motion by
means of pinions in a similar manner to that in the aforesaid mixer; the evaporator
also contains a serpentine heating coil or pipe into which steam is admitted at the
upper end and passes out at the lower end condensed to return to the generator
from which it is supplied; a water gauge glass permits of ascertaining the exact
quantity of liquid introduced into the said evaporator.
: The filtered ammoniacal liquid, containing the metallic oxide in solution, and
maintained by means of the said coil at a temperature of about twenty five or
_thirty degrees, is then subjected to the action of an exhaust pump capable of pro-
ducing in the said evaporator a partial vacuum; under these conditious, in less than-
two hours the proportion of ammonia contained in the liquid can be reduced to one
tenth; it is needless to proceed further, because at this degree of concentration the
liquor contains only traces of zinc and because this liquor will serve to regenerato
the concentrated ammoniacal liquid.
The-metallic-oxide which is precipitated during the operation-accumulates-at-
the bottom of the apparatus and the liquid above can be drawn off successively-by-
means of three cocks placed at different levels which admit it to another tank by
means of a pipe; the agitator is then set in motion and a cock opened to admit
into a filter the oxide or the carbonate in suspension in the water; another cock
permitting, if-necessary,-the-introduction_of_pure water to effect the withdrawal
_ of the particles of oxido.
The bottom of the said filter is formed-of-a-perforated-metal-plate covered with_
wool or felt upon which are collected the residues from both the operations, to be
dried and calcined.
As above stated it is not necessary to employ a vacuum to extract the ammonia
from its solution and effect the precipitation of the oxides or carbonates of zinc or
copper; heat alone can be employed to attain these results; in this case I employ
for this purpose an arrangement in which the ammoniacal solution which passes
into the alembic is heated by a furnace or other suitable means and after some
hours of ebullition nearly the whole of the ammonia escapes by a serpentine coil
or pipe with the condensed water and passes into reservoirs in which the
ammoniacal liquid is regenerated to be employed in subsequent operations.
When it is judged that the whole of the ammonia has been extracted by
distillation an outlet cock is opened and the agitator is set in motion so as to
detach the deposit which then flows with the hot water into a filter similar to that
above described; the liquid, still slightly ammoniacal, passes into a refrigerator
having compartments in which a current of cold water circulates for the purpose of
lowering the temperature before the liquid passes into the said tanks or reservoirs,
where the ammoniacal liquid is regenerated; it is important to utilize tho said
slightly ammoniacal liquid in order to avoid a sensible loss of this alkali.
The improved process above described can be applied to the separation of the
copper and zinc contained in complex ores, either for the purpose of utilizing these
two metals only, or in order to isolate them from other metals which must be
extracted separately; thus, for example, in treating calamine containing lead, in
the manner above described, carbonate of lead is formed in the residues unattacked,
and a single washing frees it from gangue.
The construction and arrangement of the different parts of the apparatus above
described can be varied or modified without materially changing the whole
arrangement of carrying the said invention into practice.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
11th May 1883.
WILLIAM ROBERT LAKE, of the Firm of Haseltino, Lake & C° Patent Agents
Southampton Buildings, London. "AN IMPROVED PROCESS AND APPARATUS
FOR OBTAINING ZINC AND COPPER FROM ORES OR OTHER SUBSTANCES" A. com-
munication to me from abroad by Leon Louis Charlos Krafft and John Edward
Schischkar, both of Paris, France.
Tho aqueous solutions of ammoniacal gas and of carbonate of ammonia have the
property of dissolving oxides and carbonates of copper and zinc and the latter are
precipitated if the ammonia or the carbonate of ammonia are extracted from their
solutions, it is upon the application of this property of ammonia that this method
or process for the treatment of copper and zinc ores is based.
The two ammoniacal solutions act in the same manner but it is liquid ammonia,
that is to say, ammonia in solution in water, that is referred to in the following
description.
The ammonia only dissolves the oxides and carbonates of copper and zinc in the
ores, which naturally contain them, otherwise it is necessary to roast them
completely several times with carbon in order to decompose the sulphates,
antimoniates, arseniates and other matters which may be contained therein and
which will occasion a great loss in the treatment of the ores.
The solution of ammonia of commerce at twenty degrees Baumé which contains
about five hundred times its volume of ammoniacal gas, dissolves such a quantity
of oxide and carbonato that the proportion of metal dissolved is 0.13 of its weight,
in practice it is necessary to employ ten parts by weight of liquid ammonia of
commerce to one part by weight of the metal contained in the ore in the form of
oxide or carbonate.
The said invention comprises two principal series of operations, that is to say ;-
First, the dissolving of the oxides or carbonates of zinc or copper in the ammoniacal
liquid, the washing and separation of the gangue and the filtration of the liquid
containing the metal in solution. And second the precipitation of the dissolved
oxides or carbonates by the expulsion of the ammoniacal gas from its solution, the
washing and separation of the said oxides or carbonates, the filtration and cooling
of the liquid still containing a certain quantity of ammonia, and finally the
regoneration of the concentrated ammoniacal liquid designed to be employed in
subsequent operations.
In carrying out these two principal operations for the treatment of copper or
zinc ores, I employ special apparatus, the arrangement of which varios according to
whether the ammoniacal gas is driven from its solution by the action of heat alone,
or by the action of a vacuum, the heat being applied only to prevent the temperature
in the apparatus from falling below from twenty five to thirty degrees centigrade.
When a vacuum is employed the arrangement which I prefer is shown in
Figure 1 of the accompanying drawings and necessitates the use of a powerful air-
pump. When heat alone is employed, the heat is furnished either by means of
steam or by the direct application of heat from a furnace. The apparatus which
I employ in this case is shown in Figure 2.
I will describe successively the different arrangements above indicated and
corresponding with the two modes of extracting the ammoniacal gas contained in
the solutions.
In dissolving oxides or carbonates of zinc or copper in ammonia, I employ the
following arrangement as shown in Figure 1, that is to say; The ore, pulverized

page_text: and passed through a N° 20 sieve that is to say, one of which the meshes are
less than one millimetre, is brought in a wagon B to the top of a mixing vessel A.
The hopper c being charged is then opened by allowing the doors S, S, to fall, these
doors are raised again by means of rods t and the contents of the wagon are
omptied into the said hopper, and will serve for the succeeding operation and to
ensure the tightness of the closure.
The said mixing vessel A is made of sheet metal and of cylindrical form, it
contains a half helix, or screw blade H set in motion by means of a bevel gear-
wheel, actuated by a motor; this screw-blade is designed to constantly agitate
the mixture.
After the introduction of the ore the volume of ammonia corresponding with
the weight of the ore is admitted by means of a cock d' situated at the upper part
of the apparatus, the level of the liquid being easily ascertained by a gauge glass n;
the operation must be effected at the ambient temperature, any elevation of the
temperature diminishing the quantity of ammoniacal gas dissolved and causing a
useless tension of the gas.
In less than two hours, the dissolution of the oxide or carbonate contained in the
oro is terminated; the agitator is then stopped and the liquid contained in the
apparatus is allowed-to-settle for about thirty minutes and is then successively
drawn off by three cocks a-ala placed at different-levels; the clouded ammoniacal
solution flows into a tank D by means of a pipe-b.-
The sandy residues left in the mixing vessel still remain impregnated-with-
ammonia containing metallic oxide in solution; a suitable volume of pure
-ammoniacal liquid is then introduced into the apparatus by the cock d¹ and the
agitator is again set in motion; the liquid is then allowed to settle, drawn off
as above described and added to the liquid in the tank.
The sand or pulverulent gangue remains in the apparatus, containing only nearly
pure ammonia which can be recovered; for this purpose a valvo-V--is--opened and-
a certain quantity of water is admitted into the mixing vessel by means of a cock e
the agitator is then set in motion; all the sand with a certain quantity of water
passes into a boiler E arranged for this purpose a little below the lower level of
the mixing vessel. The said valve V and cock e are again closed and another
operation is commenced. The complete operation occupies two bours or three at
the most.
In order to extract the ammonia contained in the sand and in the washing water
in the boiler E, the latter is, by means of a pipe at m, placed in communication with
a powerful air-pump which effects an energetic exhaustion and at the same time
steam is introduced by means of a pipe h; the ammoniacal gas exhausted is driven
into chambers for regenerating the ammoniacal liquid.
The ammoniacal gas under a pressure of fifty centimetres of mercury and the
temperature of the liquid being maintained at twenty five or thirty degrees
centigrade is almost entirely extracted in one hour. The exhaust valve at m is
then closed, as well as the steam inlet h and a valve T and cock e¹ are opened, and
the interior of the. boiler is cleansed of the sand which it contains through the
man-hole O.
As above stated the ammoniacal solution charged with zinc in solution, which
passes into the said tank D, is cloudy, it is again taken by a rotary pump P and
forced through a pressure filter F in which the filtering material is asbestos or wool
coinpressed between two perforated plates, the apparatus being so arranged that
these materials can be replaced with facility.
The lower conical part of the filter is furnished with a rotary shaft set in motion
by means of a belt and a pulley d'which moves a circular: brush f designed to
constantly cleanse the lower perforated plate of the filter and to detach the sediment
therefrom, which sediment falls to the bottom of the filter where an agitator
keeps it in suspension so that it can be extracted from time to time by means of
a cock c.
This filtration would be needless for the cupreous solutions and for the preparation
:

page_text: of oxide of zinc, with a view to the manufacture of this metal; it is on the contrary
indispensable if it is desired to apply the oxide of zinc thereby obtained to the
manufacture of colors.
This operation would be insufficient for obtaining oxide of zinc absolutely pure
with calamine or ordinary zinc ore which is impure. In this case, it would be
necessary to immerse plates of zine for twenty four hours in the filtered ammoniacal
liquor which would precipitate the lead, cadmium, or other matters which might
accompany the zinc in the solution.
As above stated, the oxides or carbonates contained in zinc or copper ores can be
dissolved without employing a vacuum, in this case I employ another arrangement
of apparatus shown in Figure 2, that is to say; The mixing apparatus M is formed
of a cylinder of sheet metal terminated by semi-spherical portions and rovolving
upon two hollow axles, one of which receives the driving pulleys and the other a
pipe N passing through a stuffing box and connected to the pipes for supplying
water, ammonia and compressed air to the apparatus.
Towards the middle of the cylindrical wall of the receptacle M is arranged
a filter Q enclosed between two sheets of metal closed by a tight cover provided with
a cock; on the opposite sido of this receptacle is arranged laterally a manhole r
which serves for charging the receptacle with ore.
The operation is as follows, the proportions of ammonia and of the ore to be
treated being employed as above stated, that is to say -The ore is first introduced
through the manholer which is then hermetically closed, the requisite quantity of
ammonia is then admitted by the said pipe and the apparatus is rotated. It is
stopped after working for two hours, care being taken to stop the drum or receptacle
in such a manner that the filter Q is at the undersido, the tube q is then fitted, the
extremity of which tube is flexible, and the cock u is opened to admit the com-
pressed air, under the action of which the filtered solution passes from the tube o̟
into an alembic or still R.
Instead of operating by pressure, the operation might be performed equally well
by suction by previously creating a vacuum in the said alembic or still.
When the receptacle M is emptied, the cock u is closed, the tubo q is disconnected
and the washing is then proceeded with by again admitting a certain quantity of
ammonia and again rotating the said receptacle, it is afterwards stopped and the
filtration effected as above described; two washings are thus effected with ammonia,
then one or two with water so as not to leave any metal in the sediment.
The sediment is emptied out through the manhole which is brought to the
underside of the apparatus, into which admitted a strong current of water and
which is kept in motion during this operation; the waste material extracted by
the water flows into a channel Larrang for this purpose below the said apparatus,
and a fresh operation can be proceeded w. h.
1
In the precipitation of dissolved oxides or carbonates, by the extraction of the
ammoniacal gas contained in the solution, when the operation is effected by means
of a vacuum, I adopt the following arrangement of the apparatus as shown on the
right hand side in Figure 1, that is to say the filtered liquor is collected in the
tank A' and is taken therefrom by the rotary pump P¹ which delivers it into an
evaporator S. This evaporator which is made of strong sheet iron is provided
inside with a helical agitator H set in motion by means of bevel gear wheels J¹
in a similar manner to that in the mixing vessel A; the evaporator also contains a
serpentine beating coil G into which steam is admitted at K and passes out at K¹
condensed to return to the generator from which it is supplied; a water gauge
glass n¹ permits of ascertaining the exact quantity of liquid introduced into the
said evaporator.
The filtered ammoniacal liquid, containing the metallic oxide in solution and
maintained by means of the said coil G at a temperature of about from twenty five
to thirty degrees centigrade is then subjected to the action of an exhaust pump
capable of producing in the said evaporator a partial vacuum represented by
forty contimeters of mercury, under these conditions, in less than two hours the

page_text: proportion of ammonia contained in the liquid can be reduced to ono tenth; it is
needless to proceed further because at this degree of concentration the liquor
contains only traces of zinc and because this liquor will serve to regenerate the
concentrated ammoniacal liquid.
The metallic oxide which is precipitated during the operation accumulates at tho
bottom of the apparatus and the liquid is drawn off successively by means of three
cocks placed at different levels, which cocks admit it to another tank W by
means of a pipe g; the agitator H' is then set in motion and the cock y opened to
admit into a filter F¹ the oxide or the carbonato in suspension in the water;
another cock e permits if necessary, the introduction of pure water to effect the
withdrawal of tho particles of oxide.
The bottom of the filter F' is formed of a perforated metal plate covered with
wool or felt upon which are collected the residues from both the operations, to be
dried and calcined.
As above stated, it is not necessary to employ a vacuum to extract the ammonia
from its solution and effect the precipitation of the oxides or carbonates of zinc or
copper; heat alone can be employed to attain these results; in this case I employ
the arrangement shewn on the right hand side. of Figure 2. The ammoniacal
solution passed into the alembic or still R is heated by a furnace U or other
suitable means and after some hours of ebullition nearly the whole of the ammonia
escapes by a serpentine coil X with the condensed water and passes into
reservoirs-Z,-Z, Z, in which the ammoniacal liquid is regenerated to be employed
in subsequent-operations.
When it is judged that the whole-of-the-ammonia has been-exhausted by
distillation an outlet cock Y is opened and the agitator H fitted at the bottom of
the said still is set in motion so as to detach the deposit which then flows with the
hot water into a filter F" similar to the filter F' above described; the liquid still
slightly ammoniacal-passes into a refrigerator W₁ having compartments in which a
-current of cold water circulates for the purpose-of-lowering the temperature before
the liquid passes through-the pipe w into the vessels Z, Z, 2" where-the
ammoniacal liquid is regenerated; it is important to utilize_the_said slightly
ammoniacal liquid in order to avoid a sensible loss of this alkali.
The improved process above described can be applied to the separation of the
copper and zinc contained in complex ores; either for the purpose of utilizing thesc
two metals only, or in order to isolate them from other inetals which must be
extracted separately, thus, for example, in treating calamine containing lead, in the
manner above described, carbonate of lead is found in the residues unattacked and
a single washing frees it from gangue. Other materials, for example refuse copper
or zinc, such as cuttings or filings, and cupreous or zinciferous solutions, may be
treated by the above described process
The construction and arrangement of the different parts of the apparatus
above described and shewn in the accompanying Drawings may be varied or
modified without materially changing the mode of carrying the said Invention into
practice.
Having thus fully described the said Invention as communicated to me by my
foreign Correspondents and the manner of performing the same I wish it understood
that I claim
The improved process and apparatus above described and shewn in the
accompanying Drawings for obtaining zinc and copper from ores or other
substances containing these metals by means of solutions of ammonia or of
carbonate of ammonia, the improvements being essentially characterized as
follows, varying according to whether a vacuum or heat only is used to expel the
ammoniacal gas from these solutions, that is to say:-When a vacuum is used,
the employment of the following apparatuses, vie :-
First. The dissolving apparatus consisting of a vertical mixing vessel having a
helix or screw-blade and provided with a hopper and with cocks for the

page_text: introduction of ammoniacal liquid or of water as well as for the decantation of the
solutions and the discharge of the residues.
Second. The closed receiver for effecting the washings and for the extraction,
under the action of a vacuum combined with heat, of the ammoniacal gas which is
contained in the residues.
Third. The filtering apparatus operating under pressure and provided with
means for cleaning and renowing the filtering material, and for the discharge of
sediment, whereby the separation can be effected of foreign matters present in the
liquid after decantation from the mixing vessel, into which it is forced again by
means of a pump.
Fourth. The evaporator into which a pump raises the filtered liquid, and which
is designed to extract, under the action of a vacuum, the ammoniacal gas contained
in the solutions and thus cause the precipitation of the oxides or carbonates
dissolved, the said apparatus being heated by an interior serpentine coil so as to
avoid the cooling of the liquid by evaporation and being provided with a
mixing vessel having a helix or screw-blade, and with cocks for the decantation
of the liquid and the introduction, if necessary, of washing water into the
apparatus.
Fifth. The filtering apparatus designed for the separation of the precipitated
oxides or carbonates as they proceed from the evaporator.
Sixth. The utilization of the decanted liquid from the evaporator for the
regeneration of the ammoniacal liquor intended for subsequent operations, by
means of vessels into which the exhaust pump forces the ammonia as fast as it is
extracted from its solution in the said evaporator.
When heat only is used to extract the ammoniacal gas from its solution the
employment of the following apparatuses, viz :-
First. The revolving drum or receptacle designed to effect successively the
solution, the washing and the filtration of the substances introduced and provided
for this purpose with an aperture for the introduction and discharge of the said
substances, a filter and pipes for conducting the ammoniacal liquor, water and
compressed air.
Second. The alembic or still, heated by an open fire or by steam, for extracting
the ammoniacal gas from its solution in order to effect the precipitation of the
oxides or carbonates dissolved, the said still being provided with an agitator or
helix at its lower part and with cocks for regulating the ingress and egress of the
liquid and steam and the discharge of the materials treated.
Third. The filtering apparatus designed to separate the oxides or carbonates from
the liquid proceeding from the alembic or still.
Fourth. The refrigerator provided with compartments and arranged to have a
circulation of cold water to cool the filtered liquid which is intended to serve for
the regeneration of the ammoniacal liquor.
Fifth. The refrigerating serpentine coil for the condensation of vapours produced
in the alembic or still, and for cooling the ammoniacal gas coming with the vapors,
previous to its introduction into the regenerating apparatus.
Sixth. The regenerating apparatus for the concentrated ammoniacal liquor
required for the subsequent operations.
All the said apparatuses being constructed and arranged to operate substantially
as described for the purposes specified.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Eleventh day of May in the year of our Lord one thousand
WM ROBT LAKE (L.S.)