IMPROVEMENTS IN THE TREATMENT OF ZINC. ORES AND METALS, AND IN APPARATUS EMPLOYED THEREIN
Year: 1872

page_text: LETTERS PATENT to John Henry Johnson, of 47,. Lincoln's Inn Fields,
OTHER VOLATILE
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN THE TREATMENT OF ZINC. ORES AND
METALS, AND IN APPARATUS EMPLOYED THEREIN."-A communication
from abroad by La Société Metallurgique pour l'Exploitation des
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 10th February 1872.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE TREATMENT OF ZINC ORES AND OTHER
VOLATILE METALS, AND IN APPARATUS EMPLOYED. THEREIN," a communication
to me from abroad by La Société Metallurgique pour l'Exploitation des
Procèdès Ponsard, of Paris, France, to be as follows:-
This Invention relates to a novel mode of and means for treating zinc

page_text: ores and other volatile metals, such for example as mercury and anti-
mony, whereby the operation of reduction is rendered a continuous one,
and a furnace of comparatively small dimensions will suffice for a
considerable production of metal, particularly zinc, when treating ores of
that metal. Moreover, considerable economy in the manufacture is ¦
effected, inasmuch as the tubes, pots, and crucibles generally employed
are entirely dispensed with, whilst the charging and discharging of the
products is effected in a continuous and economical manner.
The essential features of this Invention are the charging and dis-
charging the ores of zinc and other volatile metals on to and from the
inclined sole or hearth of a reverberatory furnace, where they are
subjected to the action of an essentially reducing flame, and elevated
to a sufficient temperature to produce the distillation of the metal.
The metallic vapours pass off directly from the upper end or mouth
of the inclined furnace into a condenser, so constructed that the
carbonic oxyde gas from the furnace, more or less mixed with car-
bonic acid but still combustible, may be cooled therein, and be thence
directed to a furnace where it is burnt for the purpose of heating:
the regenerator which supplys the metal furnace with the hot air
necessary for the combustion of the gas from the gas generator.
The carbonic oxyde gas from the gas generator meets the hot air from
the heat regenerator in a combustion chamber before entering the
reverberatory furnace.. The furnace is charged from a hopper situate
in the roof of the furnace at its upper end, and is spread over the
inclined floor by rakes or otherwise worked through side doors. As fast
as the distillation of one portion of the ore is completed this portion is
pushed down into a collecting basin or well situate at the bottom of the
inclined floor, and from this receptacle a portion of the contents is
discharged from time to time through a sliding door into a wagon or
wheeled receptacle beneath.
The condenser consists of a double sided chamber having several
double partitions therein, the said sides and partitions being always
kept filled with cold water in order to form a surface condenser.
In addition to these condensing surfaces numerous rose jets may
be fitted inside the condenser in order to produce fine showers of
cold water therein. The pipe through which the cooled gases pass

page_text: from the condenser to the heating furnace before referred to, is fitted
with a throttle valve to maintain a sufficient pressure inside the con-
denser. The double sides of the condenser dip at their lower edges into
an open tank of water, and are supported on a metal frame in the said
tank.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 10th August 1872.
Once on Augu
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Mid-
dlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of February, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
that I, the said John Henry Johnson; my executors, administrators,
and assigns, or such others as I, the said John Henry Johnson, my
executors, administrators, or 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,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN TNE TREATMENT OF ZINC ORES AND OTHER VOLATILE METALS,
AND IN APPARATUS EMPLOYED THEREIN," a communication to me from abroad
by La Société Metallurgique pour l'Exploitation des Procèdès Ponsard, of
Paris, France, upon the condition (amongst others) that I, the said John
Henry Johnson, my executors or administrators, by an instrument
in writing under my hand and seal, 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 Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
"
±

page_text: NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accom-
panying Drawings, and to the letters and figures marked thereon, that
is to say :-
The said Invention relates to a novel mode or method of treating the
ores of volatile metals, more particularly zinc, and has for its chief
object the dispensing with tubes or retorts in the distillation of the ore
by reducing and distilling the ore upon the hearth of a reverberatory
furnace heated by a current of carbonic oxyde gas at an elevated tempe-
rature, or a mixture of carbonic oxyde and carbonie acid; in fact by a
carburetting gas raised to a sufficiently elevated temperature to effect
the distillation of the metal without "fritting" the materials.
The apparatus employed consists of a reverberatory furnace with an
inclined hearth, provided with a gas generator for the production of the
carbonic oxyde gas, and with a surface condenser and injectors for
cooling and condensing the metallic surfaces.
And in order that my said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings,
the same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 represents a vertical longitudinal section of the improved
furnace for treating volatile metals; Figure 2 is a transverse vertical
section of the condenser taken along the line A, B; and Figure 3 is a
horizontal section of the furnace and condenser.
The reducing gas may be produced in an ordinary gas generator, pro-
vided that care be taken to regulate exactly the quantity of hot air
(obtained from a heat regenerator) that is mixed therewith in order
that the resulting flame shall always be a reducing flame, also that the
temperature shall not be raised beyond that necessary for a proper
distillation of the ore. It is moreover desirable in this case to dispose
on the fire-bridge a series of bricks placed obliquely, and forming
passages between them in reverse directions the one from the other,
in order to mix internally the combustible gases with air, and ensure
the expansion of the flame over the whole surface of the hearth.

page_text: its lower part for that purpose.
The
It will be understood that the surface
condenser may be made of any required form and size, in proportion to
the quantity of vapours which are to be condensed therein.
vapours which have escaped the primary condenser enter as herein-
before stated, along with the gases into a second condenser composed of
metal, and maintained constantly cool by means of currents of water
and numerous jets falling in a shower for the purpose of condensing the
metal remaining in the condition of vapour, and which falls into the
lower basin of water in the state of droplets of metallic zinc, which are
readily withdrawn with rakes or shovels.
The apparatus shewn on the Drawing consists of a large vat or vessel n
composed of sheet metal, provided with an overflow pipe p, the sides of
which vessel are widened out so as to. facilitate the removal of the zinc
made. This vessel n carries on a cast-iron rectangular support a double
case of metal provided with double partitions, the internal sides q of
which form surface condensers; the apparatus is also provided with rose
jets suitably directed, which admit of a shower of cold water being
injected into the apparatus for the purpose of accelerating the cooling of
the hot gases proceeding from the furnace, the outlet of which gases are
retarded by the baffled plates formed by the double partitions q.
The incondensible gases are exhausted at the opposite end of the
condenser, either by means of an exhauster, by the aid of a chimney o,
into which they pass after having been burnt in a special furnace, in
order to serve for the heating of a heat regenerator destined to supply
the hot air for the combustion of the gases which proceed from the gas
generator, or for any other purpose.
In the Drawing annexed the gases which pass out through the pipe h
are directed to the furnace of the heat regenerator i (to which access is
readily obtained by the pit k), and serve for the heating of the air which
passes through the conduit m for the purpose of supporting combustion
in the gas generator, access to which is afforded by means of the pit 7.
It will be understood that should any particles of uncondensed vapours
still remain in the gases which leave the pipe h, they will be burnt in
the regenerator, where the oxyde of zinc formed may be collected, and
which it is simply requisite to wash in order to obtain it in the condition
of zinc white.
I may observe that the zine vanours may be condensed by the employ-

page_text: ment of cold surfaces only, and without the addition of water.in the
apparatus, in order to avoid the production of steam, which might affect
the combustion of the cold gases employed for the heating of the
regenerator. By this arrangement of condenser the re-entrance of
air and loss of metallic vapour are obviated. Moreover, by the
use of a valve disposed in the outlet pipe h a sufficiently low pressure
may be maintained in the condenser and furnace to prevent any
loss of zinc vapour, and hinder the re-admission of air into the
apparatus.
1 It immediately results from the application of the process herein.
before described that the whole of the metal contained in the ore is
collected―.
:
First. In the condition of molten metal in the primary surface
condenser.
☐ Secondly. In the condition of droplets more or less oxydised, and
capable of being readily treated in the second or injection condenser.
n
Thirdly. In the condition of zinc white in the chambers of the
regenerator.
It is obvious that by allowing the air on the contrary to freely enter
the furnace, and by maintaining therein an oxydizing flame, oxyde of
zinc or zinc white may be readily obtained, which would be deposited
in the condensers, and especially in the vessel n.
This process is equally applicable to the treatment of the ores of
volatile metals other than zinc, such as mercury and antimony; in par-
ticular it offers the advantage of a continuous operation, and enables a
considerable production of metal to be effected with a furnace of limited
dimensions. The saving thus obtained in the cost of manufacture
is moreover considerable, as by the use of this furnace the usual
tubes, pots, crucibles, and the like are dispensed with, and the charging
and discharging of the products is effected in a continuous manner and
very economically.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion, that what I consider
to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is, -

page_text: .
First. The peculiar mode or method of treating the ores of volatile
metals, as herein-before described.
Second. The continuous charging and extraction of the ores of volatile
metals on the hearth of a reverberatory furnace, where they are subjected
to the action of an essentially reducing flame at such an elevated tem.
perature as is sufficient to produce the distillation of the metal, substan-
tially as herein-before described.
Third. The application and use to and in the treatment of the ores of
zinc and other volatile metals of the peculiar system of gas generator
known as Ponsard's, which is supplied with hot air from a heat regene-
rator, such regenerator being heated by the combustion of the reducing
gases themselves, which have served to effect the distillation of the
metal, substantially as herein-before described.
Fourth. The condensation of the metallic vapours in a double surface
and injection condenser, whence the cooled reducing gases are con-
ducted and burnt so as to heat, a regenerator which supplies the gas
generator with hot air, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, this Thirtieth day of
July One thousand eight hundred and seventy-two.