IMPROVE- MENTS IN THE TREATMENT OF ZINC AND OTHER ORES AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1860

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincolns Inn Fields,
in the County of Middlesex, and of 166, Buchanan Street, in the City
of Glasgow, North Britain, Gentleman, for the Invention of "IMPROVE-
MENTS IN THE TREATMENT OF ZINC AND OTHER ORES AND IN THE APPARATUS
EMPLOYED THEREIN."-A communication from abroad by Adrien Muller,
of Paris, and Alexandre Lencauchez, of Besançon, both in the Empire
of France, Engineers.
Sealed the 29th January 1861, and dated the 31st August 1860.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 31st August 1860.
I, JOHN HENRY JOHNSON, of 47, Lincolns Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE TREATMENT OF ZINC AND OTHER ORES AND IN THE APPARATUS
EMPLOYED THEREIN," a communication from abroad by Adrien Muller, of Paris,
and Alexandre Lencauchez, of Besançon, both in the Empire of France,
Engineers, to be as follows:-
This Invention relates to a peculiar system or mode of treating various ores,
whether containing zinc or more volatile metals, and to certain peculiar con-
structions and arrangements of apparatus employed in such treatment..

page_text: According to this Invention it is proposed to treat the metallic oxides directly
in contact with the fuel by the aid of a blast furnace. The ores and fuel are
well desiccated in suitable stoves arranged round the top of the furnace, and
heated by the waste gases, and are ground and agglomerated into blocks, each
block containing besides the ore a sufficient quantity of wood, charcoal, or
other combustible for reducing the ore, and a suitable quantity of quicklime to
produce a good slag. The desication of the blocks is facilitated by placing
them in openwork metal waggons which allow the heat to circulate freely
round their contents. The furnace is charged by means of a double hopper
placed at the top thereof, so constructed that a charge may be permitted to
descend into the furnace without allowing at the same time any of the gases
or products of combustion to escape. The vapours of zinc with the products
of combustion pass off by a series of radiating passages into a condensing and
refrigerating chamber, the top of which is provided with cold water tanks to
assist the refrigeration of the zinc vapours. A portion of the carbonic oxide
which enters the condenser with the-vapour-of-zinc-is-subsequently-directed by
the aid of a suitable fan through a tubular blast heater, whilst another portion
is directed into an annular space which surrounds the upper part of the
furnace this space being bounded on its inner side by a slightly conical cast-
iron shaft forming the upper part of the furnace and supporting the feeding
hopper, and on its outer side by the brickwork of the furnace, the annular
space between being kept supplied with combustible gases which become
heated and then pass off to the drying ovens above referred to. In order
to check the upward draught of the furnace and cause the products of com-
bustion to pass out at the radial passages herein-before mentioned, it is
proposed to introduce a current of carbonic oxide near the upper part of the
furnace. Suitable gas burners are employed in conjunction with means for
admitting atmospheric air for facilitating the combustion of the gases in the
blast heating apparatus and at the inlets for the gas into the annular space
above referred to surrounding the inner shaft of the furnace. The fan which
it is proposed to employ for exhausting the heated gases is so constructed
that the inlet shall be considerably larger than the outlet, thereby obtaining
greater pressure and force of blast. A constant current of cold water is
passed through the spindle of the fan which is made tubular for that purpose
to prevent overheating. In order to regulate the blast a conical plug is
contained inside the tuyere, and is capable of adjustment therein so as to open
or close more or less the mouth of the tuyere. The temperature of the blast
may be indicated by a pyrometer consisting of a metal bar laid in a recess on
the surface of the blast pipe and resting on porcelain or other heat-resisting

page_text: suppports. This bar is fixed at one end, and is connected at its opposite end
with a short lever arm fast on a shaft which carries a longer arm provided
with a toothed segment on its free end. This segment gears into a pinion on
the axis of an indicator, which indicates on a divided dial, through the expansion
of the bar, the heat of the blast. The whole of the working. parts of this
pyrometer are inclosed in brickwork or other good fire-resisting medium. · ·
In the treatment of non-volatile ores, such as refractory iron ore, the
products of combustion only will pass into the condensing chambers.
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 28th February 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincolns Inn Fields, in the County of Middlesex, and
of 166, Buchanan Street, in the City of Glasgow, North Britain, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of August, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth 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 THE TREATMENT OF ZINC AND OTHER ORES, AND IN THE
APPARATUS EMPLOYED THEREIN," a communication from abroad by Adrien Muller,
of Paris, and Alexandre Lencauchez, of Besançon, both in the Empire of
France, Engineers, 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, or under the hand and seal of one of them
should particularly describe and ascertain the nature of the said Inven-
tion, 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 immediately 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 accompanying Drawings and
to the letters and figures marked thereon, that is to say:
.
The said Invention relates to a peculiar system or mode of treating various
ores, whether containing zinc or non-volatile metals, and to certain peculiar
constructions and arrangements of apparatus employed in such treatment.
According to this Invention it is proposed to treat the metallic oxides
directly in contact with the fuel, by the aid of a blast furnace. The ores and
fuel are well desicated in suitable stoves arranged round the top of the furnace,
and heated by the waste gases, and are ground and agglomerated into blocks,
each block containing besides the ore a sufficient quantity of wood charcoal
or other combustible for reducing the ore, and a suitable quantity of quicklime
to produce a good slag. The desication of the blocks is facilitated by placing
them in openwork--metal waggons, which allow the heat to circulate freely
round their contents; the furnace is charged by means of a double Lopper
placed at the top thereof, so constructed that a charge may be permitted to
descend into the furnace without allowing at the same time any of the gases or
products of combustion to escape. The vapors of zinc, with the products of
combustion, pass off by a series of radiating passages into a condensing and
refrigerating chamber, the top of which is provided with cold water tanks to
assist the refrigeration of the zinc vapors. A portion of the carbonic oxide
which enters the condenser with the vapor of zinc, is subsequently directed
by the aid of a suitable fan through a tubular blast heater, whilst another
portion is directed into an annular space, which surrounds the upper part of
the furnace, this space being bounded on its inner side by a slightly conical
cast-iron shaft forming the upper part of the furnace; and supporting the
feeding hopper, and on its outer side by the brickwork of the furnace, the
annular space between being kept supplied with combustible gases, which
become beated, and then pass off to the drying ovens above referred to. In
order to check the upward draught of the furnace and cause the products of
combustion to pass out at the radiating passages herein-before mentioned, it is
proposed to introduce a current of carbonic oxide near the upper part of the
furnace. Suitable gas burners are employed in conjunction with means for
admitting atmospheric air for facilitating the combustion of the gases in the
blast-heating apparatus, and at the inlets for the gas into the annular space
above referred to, surrounding the inner shaft of the furnace. The fan which
it is proposed to employ for exhausting the heated gases is so constructed that

page_text: the inlet shall be considerably larger than the outlet, thereby obtaining greater
pressure and force of blast; a constant current of cold water is passed through
the spindle of the.fan, which is made tubular for that purpose, to prevent over
heating. In order to regulate the blast, a conical plug is contained inside the
tuyere, and is capable of adjustment therein, so as to open or close more or
less the mouth of the tuyere. The temperature of the retort may be indicated
by a pyrometer, consisting of a metal bar laid in a recess on the surface of the
blast pipe, and resting on porcelain or other heat-resisting supports; this bar
is fixed at one end, and is connected at its opposite end with a short lever arm
fast on a shaft, which carries a longer arm provided with a toothed segment
on its free end. This segment gears into a pinion on the axis of a pointer or
indicator, which indicates on a divided.dial (by the expansion of the lear) the
heat of the blast. The whole of the working parts of this pyrometer are
enclosed in brickwork or other good fire-resisting medium.
In the treatment of non-volatile ores, such as refractory iron ore, the pro-
ducts of combustion only will pass into the condensing chambers.
And in order that the said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout all the
Figures.
Figure 1 of the Drawings represents a longitudinal vertical section of the
entire apparatus in complete working order; Figure 2 is a corresponding
sectional plan taken along the lines 1, 2, 3, 4, 5, and 6 in Figure 1; Figure 3
is a plan of the top of the blast furnace; and Figure 4 is a vertical traverse
section, taken along the line 7, 8, in Figure 1.
The hearth and tuyeres of the blast furnace A may be constructed and
arranged in the ordinary manner, but the bosses are less expanded and higher
than usual; the outlets for the gas and vapor are disposed. at the belly of the
furnace, and open into an annular flue or chamber B, which encircles the lower
part of the body of the furnace.. This flue communicates through the passage
C with the condensing chambers D for the reception of the vapors of zinc.
These chambers communicate with each other by means of openings made
alternately in the upper and lower portions of their several division walls, in
order to obtain as long a circuit for the gases and vapors through the con-
densing chambers as possible, and to render the process of condensation more
regular the first of these chambers is provided with a conical closing hopper
D' for the introduction of what is known as zinc "fume" or finely divided zinc:
The hearth or floor E, which is common to all the chambers, is slightly inclined,

page_text: in order that the condensed zinc may flow freely down it, apertures being left
for that purpose at the foot of each division wall. The roof of the four last
chambers is composed of a galvanized iron water tank F, which being kept
constantly supplied with cold water, serves as a refrigerator, and greatly ex-
pedites the condensation of any remaining vapors of zinc. Large depositing
chambers L, L, are placed in communication with the condensing chambers D,
wherein the current of the gases being considerably retarded, the fume which
has been carried along by the gases is allowed to deposit. Two sets of
depositing chambers are employed, and the gases are directed into them
alternately, thereby affording facility for their being cleaned out occasionally.
Each depositing chamber is provided with a washer M, in which a. descending
shower or stream of water acts upon the gases, which enter therein from the
next chamber, and leaving the vapors of zinc pass off into suitable apparatus
to be used as fuel in the furnace. The zinc thus obtained flows off by the
channel X, Figure 2. The interior of the furnace for a distance of two or
three yards above the belly is built of fire clay lumps,-and-the-remainder,-as
far as the mouth is composed of cast iron made in short lengths or frustrums G
joined together, as shewn. This part of the furnace is concentric with the
outer brickwork, which rests upon the hollow crown G¹. This crown is
suitably hollowed out to receive the gas burners H, which are united to it by
double elbow pipes h, which connect the interior of the crown with the gas
distributors, the whole forming an effective gas-consuming apparatus. Upon
the platform at the mouth of the furnace are erected four ovens I, for heating
the fuel and mineral by the aid of the gases which pass off from the furnace.
The charge is introduced into the furnace through a cylindro-conical hopper T,
provided with a double bottom of a similar shape. This arrangement affords
facility for introducing a charge without permitting the gases to escape. At
about two-thirds the height of the furnace is fitted a small pipe t, which admits
a certain quantity of the gas which escapes from the condensing chambers, so
as to cause the gases or vapors arising from the charges to descend, and
thereby check all upward draughts or currents.. The blast furnace is supplied
with hot air from a tubular air-heating apparatus, which is itself heated by
the combustible gases escaping from the condensing and depositing chambers.
The furnace charge is made up into the form of blocks, dried as above
described, these blocks being composed of, first, the ore to be reduced; second,
the proper quantity of wood charcoal or other combustible necessary for the
reduction of such ore; and third, a sufficient quantity of lime to form a good
cinder. The reduction of the ore in the furnace being thus accomplished by
the contact with the carbon the carbonic oxide gas will be unnecessary for this

page_text: operation. The quicklime will combine with the gangue of the ore to form
the various silicates. Thus by the use of these blocks of ore fuel and lime
combined together, the transformation of carbonic oxide into carbonic acid
and the disengagement of carbonic acid which always results from the use of
castine or flux are prevented. By this system, therefore, a gaseous current
completely free from carbonic acid gas is obtained, whilst a considerable
temperature is maintained in the furnace.
I may observe, in conclusion, that when the metallic zinc descends into the
oxidising zone of the furnace, or when the oxide is carried along by a gaseous
current, which. amounts to the same, the current or draught produced by the
combustion carries along with it considerable quantities of oxide. If the
current traverses over or through masses of incandescent fuel, whether coke or
wood charcoal, the particles of oxide carried along with it are almost imme-
diately transformed into metallic vapor by parting with their oxygen to the
fuel, which in this case performs the functions of a reducer. The wood
charcoal by reason of its great porosity has this property in a high degree.
Various arrangements of apparatus may be employed for the attainment of the
end in view, which is, to cause the products of combustion and vapors of zinc
to pass over or through as large a surface as possible of incandescent fuel, in
order that should such products of combustion and vapors of zinc carry along
with them any unreduced particles, these particles will undergo their reduction
during their passage through or over the incandescent fuel.
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, the general system or mode of
reducing and treating zinc and other ores, and the arrangement and com-
bination of apparatus employed in such treatment, as herein-before
described.
In witness whereof, I, the said John Henry Johnson, have hereunto
set my hand and seal, this Twenty-sixth day of February, One thousand
J. HENRY JOHNSON. (L.s.)