AN IMPROVED PROCESS FOR SMELTING ZINC, AND APPARATUS THEREFOR.
Year: 1873

page_text: "
LETTERS PATENT to John Imray, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for the Invention of
"AN IMPROVED PROCESS FOR SMELTING ZINC, AND APPARATUS THEREFOR.'
A communication from abroad by Oscar Loiseau, of Ougrée, near
Liège, in the Kingdom of Belgium, Engineer.
-
Sealed the 9th September 1873, and dated the 5th May 1873.
PROVISIONAL SPECIFICATION left by the said John Imray at the
Office of the Commissioners of Patents, with his Petition, on the
5th May 1873.
I, JOHN IMRAY, of No. 20, Southampton Buildings, Chancery Lane,
3 in the County of Middlesex, do hereby declare the nature of the said
Invention for "AN IMPROVED PROCESS FOR SMELTING ZINC, AND APPARAtus
THEREFOR," to be as follows:-
This Invention relates to a process and apparatus for smelting zinc in
such a manner that there shall be little or no waste of metal by volatilisa-
tion; that the heat employed for smelting shall be applied directly to
the ore, and fully utilised; that retorts and other vessels ordinarily used

page_text: in reduction shall be dispensed with; and that the reduction of large
charges of ore shall be rapidly and completely effected by simple means
and by comparatively unskilled labour.
The new process consists essentially in exposing the oxide ore mingled
with powdered charcoal or carbonaceous matter in a heated oven to the
action of heated carbonic oxide gas, whereby the orc is reduced and the
metallic zinc is carried off in vapour, which is condensed into liquid zinc
by cooling the gases with which the zinc vapour is mingled under
pressure.
The apparatus by which this process is effected consists of a generating
furnace, charged with coke or charcoal or other carbonaceous substance,
into which air, preferably heated, is forced in such limited quantity that
the products of combustion consist chiefly of carbonic oxide mingled
with the unconsumed nitrogen. These products in a heated condition
are made to pass through the reducing oven, which is conveniently
placed immediately over the generating furnace, so as to receive heat
therefrom, and the floor of which is covered with a mixture of zinc ore
and carbon to such moderate thickness as will permit the gasos to act
freely upon the mass.
The gases having become charged in the oven with the vapour of
reduced zinc are led thence through exposed passages, wherein they are
cooled to such an extent as to deposit the zine in a liquid form, which
runs through tap holes in the bottoms of these passages. The conden-.
sation of the zinc vapour is aided by keeping the gases under pressure,
which is effected by forcing air into the generating furnace, and
· providing the opening for the final discharge of the gases with a loaded
valve. By immersing this outlet in water, through which the gases are
made to bubble, such portions of the zinc vapour as may be carried with
the gases are condensed.
The gases, which after passing the outlet valve may still contain a
certain amount of combustible ingredients, can be led to a boiler or other
furnace, where these ingredients can be utilised as fuel.
Sometimes it is advantageous to introduce a certain quantity of steam

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said John Imray in the Great Scal Patent Office on
the 24th October 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
IMRAY, of No. 20, Southampton Buildings, Chancery Lanc, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of May, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Imray, Her special license that I,
the said John Imray, my executors, administrators, and assigns, or such
others as I, the said John Imray, 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, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "AN IMPROVED PROCESS FOR SMELTING ZINC, AND
APPARATUS THEREFOR," a communication to him from abroad by Oscar
Loiseau, of Ougrée, near Liège, in the Kingdom of Belgium, Engineer,.
upon the condition (amongst others) that I, the said John Imray, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner tho
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next, and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Imray, 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 thereof, reference being had to the accompanying
Sheet of Drawings and to the figures and letters marked thereon, that is
to say:
This Invention relates to a process and apparatus for smelting zinc in
such a manner that there shall be little or no waste of metal by volatilisa
tion
that the heat amnloved for cinciting choll ho onlied dialle.i

page_text: the orc, and fully utilised; that retorts and other vessels ordinarily used
in reduction shall be dispensed with; and that the reduction of large
charges of ore shall be rapidly and completely effected by simple means
and by comparatively unskilled labour.
The new process consists essentially in exposing the oxide ore, mingled
with powdered charcoal or carbonaceous matter, in a heated oven to the
action of heated carbonic oxide gas, whereby the ore is reduced, and the
metallic zinc is carried off in vapour, which is condensed by cooling the
gases with which the zinc vapour is mingled under pressure, the
condensing apparatus being however maintained at such a temperature
that the zinc vapour is not precipitated in a vesicular state, but is
condensed in a liquid state.
The apparatus by which this process is effected consists of a generating
furnace, charged with coke or charcoal or other carbonaceous substance,
into which air, preferably heated, is forced in such limited quantity that
the products of combustion consist chiefly of carbonic oxide mingled with
the unconsumed nitrogen. These products in a heated condition aro
made to pass through the reducing oven, which is conveniently placed
immediately over the generating furnace, so as to receive heat therefrom,
and the floor of which is covered with a mixture of zinc ore and carbon
to such moderate thickness as will permit the gases to act freely upon
the mass.
'
The gases having become charged in the oven with the vapour of
reduced zinc are led thence through exposed passages, wherein they are
cooled to such an extent as to deposit the zinc in a liquid form, which
runs through tap holes in the bottoms of these passages. The conden-
sation of the zine vapour is aided by keeping the gases under pressure,
which is effected by forcing air into the generating furnace, and providing
the opening for the final discharge of the gases with a loaded valve. By
immersing this outlet in water, through which the gases are made to
bubble, such portions of the zinc vapour as may be carried with the
gases are condensed.
The gases, which after passing the outlet valve may still contain a
certain amount of combustible ingredients, can be led to a boiler or
other furnace, where these ingredients can be utilised as fucl.
Sometimes it is advantageous to introduce a certain quantity of steam
along with the gases into the reducing oven.

page_text: The Figures on the accompanying Sheet of Drawings show the con-
struction and arrangement of apparatus, whereby the process above
described is carried out according to this Invention.
Fig. 1 represents a longitudinal and Fig. 2 a transverse section of the
gas producing furnace and reducing oven; Fig. 3 is a sectional plan;
and Fig. 4 is a front view of the same.
Fig. 5 represents a side view of the furnace and oven connected with
the condensing apparatus, which is shown in section; and Fig. 6 repre-
sents a plan of the condensing apparatus.
A is the compartment or furnace for the production of carbonic oxide
gas; it is charged with coke introduced from above by channels J, cachi
of which is provided with an air-tight covor; I is a door for poking and
equalising the coke in the compartment A. Hot air is supplied to this
compartment by tuyeres D from a hot blast pipe B, the quantity supplied
being regulated by a valve C, to produce such combustion that only
carbonic oxide mingled with the unconsumed nitrogen of the air is
evolved. The hot gas ascends by flucs K to a chamber over the crown
of the reducing oven E, whence it enters the reducing oven by a passage L
at one end thereof. The oven E is supplied with the ore to be reduced,
mingled with coke or other carbonaceous matter in small picces, and in
such quantity as to prevent the formation of carbonic acid during
reduction. The mixed material, which may be previously heated, is
introduced from above by a channel G, provided with an air-tight cover,
and is spread over the floor F, access for raking and clearing out
residue being given by a door H. The oven E, being highly heated by
the combustion of the coke in A, and the circulation of the hot gascous
products round it, and the hot gas from A being made to play over the
ore in E in its course from the passage L to apertures M at the opposite
end of the oven, the ore becomes reduced, and zinc in a state of vapour
is carried off by the issuing gascous current. At first starting the gases
are allowed to escape from the oven by an opening N, until the issuing
flame shews that the reduction has commenced; the opening N being
then closed by a tight cover the gaseous products from the reducing oven
pass by openings O into numerous vertical channels R formed in the
masonry; the openings O are provided with slides P, to which access is
given from without by doors Q; at the end of the reducing operation the
slides P are closed. The channels Ṛ communicate with cach other by

page_text: openings », formed alternately near their upper and lower ends, so that
the gascous matter supplied to the middle channels have to pass in a
zig-zag direction, down the one and up the other, till it finally issues
from the outer channels by channels S into flucs communicating by pipes
with the condensing apparatus. It will be seen that the channels R are
made to diminish in sectional area from the middle outwards; T arc
openings provided with caps for giving access to clear the passages S;
the gascous matter in its passage through the successive channels R
deposits a large proportion of the zinc in a liquid state, which runs out
by small openings & at the bottoms of the channels R, which are sloped
to facilitate the outflow of the molten metal.
The residue of the zinc is separated from the gascous matter by tho
condensing apparatus in the following manner :-The gases after leaving
the last of the channels R are conveyed by pipes U to a number of
vertical vessels V, made of iron plate, and placed in a tank of cold
water; in these vessels there is a still farther precipitation of the
residuary zinc in a versicular or granular condition; from the last of the
series of vessels V the gases pass by a pipe U₁, the end of wliich is
immersed in water Y in a tank, and is provided with a valve X, which
can be loaded to the desired pressure by weights placed on a rod t,
projecting upwards from the lever of the valve; the valve X and mouth
of the pipe U are closed over, so that when the valve opens the gases
washed by bubbling up through the water are received in a compart-
ment Z sealed from the outer air; from this compartment the gases can
be conducted by pipes to form gascous fuel for the boilers of the blowing
engines, or for roasting or heating ores, or for other heating purposes.
Such of the zinc as may have escaped precipitation in the channels R or
vessels V is condensed and precipitated in the water Y.
Having thus described the nature of this Invention, and in what
manner the same is to be performed, as communicated to me by my
foreign corresponden, I claim,-
First. The process of reducing zinc ore by exposing it mingled with
carbonaceous matter in a heated oven to the action of licated carbonic
oxide at such temperature that the zinc is separated and carried off in a
state of vapour, substantially as herein described.
Second. The method of condensing the metallic vapour, by passing the
gases with which it is mingled under pressure through channels main-

page_text: tained at such a temperature that the zinc is deposited in a liquid state,
substantially as herein described.
Third. The method of farther condensing) and washing the gases by
passing them through cooled pipes and vessels, and finally causing them
to bubble through water, substantially as herein described.
Fourth. The combination of the reducing oven or compartment E and
the condensing channels R in one structure, with the furnace A for
generating the carbonic oxide in such manner that the heat of the latter
is utilised for maintaining the temperature of the reducing oven and
condensing channels, substantially as herein described.
Fifth. The use of condensing and washing apparatus, constructed and
operating substantially as described in reference to Figs. 5 and 6, in
combination with the gas-producing and reducing apparatus referred to
above.
Sixth. Maintaining pressure exceeding that of the atmosphere in the
several chambers, channels, and pipes of the apparatus, by the supply of
hot air under pressure to the gas-generating furnace A, and by the use
of a loaded valve X at the orifice of the discharge pipe, substantially as
herein described.
In witness whereof, I, the said John Imray, have hereunto set
my hand and seal, this Tenth day of October, in the year of our
Lord One thousand eight hundred and seventy-three.
TATE
JOHN IMRAY. (L.S.)