Improvements relating to the Treatment of Ores and other Compounds containing Metals and Sulphur, and to Apparatus therefor.
Year: 1892

page_text: Date of Application, 5th Apr., 1892
Complete Specification Left, 5th Jan., 1893-Accepted. 5th July 1893
PROVISIONAL SPECIFICATION.
Improvements relating to the Treatment of Ores and other
Compounds containing Metals and Sulphur, and to Apparatus
therefor.
We, HENRY RYAN LEWIS, of 7, Draper's Gardens, in the City of London,
Mining Engineer and Metallurgist, and CHARLES GELSTHARP, of 86, Addison
Road, Heaton, Newcastle-on-Tyne, in the County of Northumberland, Metallurgist,
do hereby declare the nature of this invention to be as follows:-
This invention relates to the treatment of ores and other compounds containing
metals and sulphur, and to apparatus therefor, and has for its object the extraction
of the metals from such ores or compounds and the recovery of the sulphur and
other valuable products contained therein.
An important feature of our said invention is the treatment of the ores or
compounds in such a manner that the sulphur burnt off from the same in one stage
of the process, is utilized for maintaining the required temperature in a succeeding
stage thereof, and the gases or vapours evolved in these two stages are kept
separate from each other, so that sulphuric acid or sulphur may be obtained from
the gases or vapours evolved in the first stage, whilst hydrochloric acid or
sulphuric acid and any volatilized metals are obtained from the gases or vapours
evolved in the succeeding stage of the process.
Our said invention comprises an improved process wherein the said ores or
compounds, after being crushed or ground, are roasted or calcined and chlorinated
in a furnace or apparatus in which, after the required temperature has been
obtained by the burning of fuel, such as coal, coke or wood, such temperature will
be maintained by the burning of the sulphur contained in the said ores
compounds, without any additional or extra fuel, and in which the gases or vapours
evolved may be separated and valuable products obtained therefrom.
ог
According to the class or grade of the ores or compounds, we vary the process
and apparatus which we employ. In treating first-class ores or compounds, we
first crush or grind them, and then pass them through an improved calcining or
roasting furnace or apparatus constructed with a number of horizontal beds or
shelves one above another, of much larger dimensions than those at present in use,
but so arranged that, after the proper temperature is obtained by the burning of
coal, coke, wood or other fuel, such temperature will be kept up by the burning
of the sulphur contained in the ore or compounds while passing over the shelves or
beds, without any extra fuel. We convey the hot gases or vapours produced in
the upper beds or shelves by the burning of the sulphur in the ore or compounds,
by means of suitable flues and dampers or gates, under the lower beds or shelves
for the purpose of heating the ore or compound thereon, and then by flues into a
condenser or vitriol chamber. We convey the gases or vapours produced on the
lower beds or shelves, by means of separate flues and dampers or gates, into a
condenser, without allowing them to come in contact with the ore treated or the
gases produced on the upper beds, so that any metals that may be volatilized may
be recovered, and the sulphuric or hydrochloric acid condensed; these acids may
be used for leaching the roasted ores or compounds.
After the bulk of the sulphur is burnt off on the upper beds, and the ore or
compounds are passed down on to the lower beds or shelves, we close the gates or
dampers between the lower and upper beds or shelves, and, when necessary,
introduce a quantity of common salt or other chloride or acid or sulphate of iron or
other sulphate, or a mixture of these substances, and thoroughly mix the same
with the ore or compound, so that the metals may be all converted into chlorides

page_text: or sulphates. The ore or compound is then drawn out of the apparatus and may
be smelted or leached, and the metals precipitated by any well-known method.
In treating the second class of ores or compounds, after crushing or grinding
them, we pass them through an improved roasting or calcining furnace or apparatus
constructed with a number of horizontal beds or shelves arranged one above
another, and communicating with one another by suitable channels, and adjoining
the beds or shelves, or under the bottom beds or shelves, we construct a chamber
or fire-place which we keep filled with hot coke or other carbonaceous matter, or
with peroxide of iron. We connect with this chamber, another similar.chamber,
filled with checkered or pigeon-holed brickwork. These chambers are so placed
that, after they have been heated to the required temperature, they will be kept
hot by the burning of the sulphur in the ore or compounds. The hot gases or
vapours produced by the burning of the sulphur in the ores on the upper shelves,
we convey by suitable flues with gates or dampers, through the chamber containing
the hot coke or carbonaceous matter, or peroxide of iron, then through the chamber
containing the checkered brickwork (for the purpose of decomposing any compounds
of sulphur with carbon, hydrogen or oxygen) and under the lower beds or shelves
for the purpose of heating the ore or compound thereon, and then into cooling
chambers, where the sulphur is deposited and collected; or, when the first
chamber is filled with peroxide of iron, the gases, after passing through it, are
passed through tubes cooled with water, when the sulphuric anhydride is condensed
and collected. The coke is kept hot by being supplied with the air contained in
the said hot gases or vapours, or, when necessary, a small quantity of air is admitted
to the chamber or fire-place for this purpose.
To the lower beds or shelves of the furnace or apparatus, we connect a separate
flue, with suitable gates or dampers, so that the gases or vapours produced on the
said lower beds or shelves may be conveyed into a separate chimney or condenser
(without coming in contact with the ore or gases on the upper beds or shelves) so
that any metals which may be volatilized may be recovered, and the sulphuric acid
or hydrochloric acid condensed. When the ores or compounds have been
sufficiently roasted on the upper shelves and have been passed down onto the lower
beds or shelves and the bulk of the sulphur burnt off, we add, if necessary, a
quantity of common salt or other chloride or acid, or sulphate of iron or other
sulphate, while the ores or compounds are maintained at the proper temperature by
the hot gases passing from the upper shelves under the lower shelves or beds.
The ore or compounds are thoroughly mixed with the salt or chloride or acid or
sulphate until all the metals are converted into chlorides or sulphates. The ores
or compounds are then drawn out of the apparatus, and may then be smelted or
leached, and the metals recovered from the solutions by any well-known method.
Dated this 5th day of April 1892.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants..
COMPLETE SPECIFICATION.
Improvements relating to the Treatment of Ores and other
Compounds containing Metals and Sulphur, and to Apparatus
therefor.
We, HENRY RYAN LEWIS, of 7 Drapers' Gardens, in the City of London,
Mining Engineer and Metallurgist, and CHARLES GELSTHARP of 86 Addison
Road, Heaton, Newcastle on Tyne, in the County of Northumberland, Metallurgist,
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:-
Our invention relates to the treatment of ores and other compounds containing

page_text: mecals and sulphur, and to apparatus therefor; and has for its object the extraction
of the metals from such ores or compounds, and the recovery of the sulphur and
other valuable products contained therein.
An important feature of our said invention is the treatment of the ores or
compounds in such a manner that the sulphur burnt off from the same in one stage
of the process is utilized for maintaining the required temperature in a succeeding
stage thereof, and the gases or vapours evolved in these two stages are kept
separate from each other, so that sulphuric acid or sulphur or sulphuric anhydride
may be obtained from the gases or vapours evolved in the first stage, whilst hydro-
chloric acid or sulphuric acid and any volatilized metals are obtained from the
gases or vapours evolved in the succeeding stage of the process.
Our said invention comprises an improved method or process of roasting or
calcining, and, if necessary, chlorinating or sulphatizing the ores or compounds, in
which process the sulphur contained in the said ores or compounds is oxidized or
burnt, and a part of the same is converted into gas or vapour, from which the
sulphur is recovered as sulphuric acid or sulphur or sulphuric anhydride; whilst
the other part combines with the metals contained in the ores or compounds to form
sulphates, and the heat produced by the oxidation or burning of the sulphur in the
first stage of the process is utilized for maintaining the required temperature in a
succeeding stage thereof; in this succeeding stage, when required, the metals
contained in the ores or compounds are chlorinated or sulphatized by adding to
them a small quantity of common salt or other chloride, chlorine, or a suitable
acid, or sulphate of iron or other sulphate, or a mixture of these substances, and
thoroughly mixing the same with the ores or compounds until all or nearly all the
metals are converted into sulphates or chlorides. The ores or compounds are
then leached with water and a small quantity of acid, and the metals are
precipitated and separated from the solutions obtained, by any well-known method
or process.
Our said invention also comprises an improved method of recovering the sulphur
or sulphuric acid or hydrochloric acid or chlorine and any volatilized metals, which
method consists in so separating the gases or vapours evolved while roasting or
calcining and chlorinating or sulphatizing the ores or compounds, that the sulphurous
or sulphuric acid evolved in the first stage of the process may be kept entirely free
from an excess of atmospheric air, and also from the products of combustion of the
fuel and from chlorine or hydrochloric acid and from metals volatilized in the latter
stage of roasting, so that the sulphur can be recovered from such sulphurous or
sulphuric acid by passing it through hot carbonaceous matter, and then into cooling
or depositing chambers; or by passing it over or through hot peroxide of iron, and
hen into cooling tubes and condensers, and there collecting the sulphuric acid or
nhydride. Or the sulphurous acid may be passed through cooling chambers or
ondensers and then into lead chambers in mixture with nitric acid fumes and steam,
nd thus be converted into vitriol; the gases evolved and metals volatilized in the
econd stage of the process being, at the same time, kept from getting mixed with
he large volume of sulphurous acid, or with an excess of atmospheric air, or with
he products of combustion of the fuel, so that they are easily condensed, and the
cids or metals recovered therefrom, by passing them, by means of suitable tubes
rflucs, through a condenser or condensers packed with chequered brick-work or
oke or both, and down which water is kept constantly trickling.
Our said invention also comprises improvements in the construction of the furnace
apparatus for roasting or calcining and chlorinating or sulphatizing the ores or
mpounds, by means of which improvements the ores or compounds can be
oroughly roasted or calcined, and chlorinated or sulphatized, without fuel (except
starting), the burning or oxidizing of the sulphur contained in the ores or
mpounds on the upper shelves of the furnace or apparatus producing the heat
cessary to maintain the lower shelves at the temperature required to convert the
etals contained in the ores or compounds into sulphates or chlorides.
According to the class or grade of the ores or compounds to be treated, we vary

page_text: the process and apparatus which we employ. In treating first-class ores or
compounds, we first crush or grind them, and then pass them through an improved
calcining or roasting furnace or apparatus constructed with a number of horizontal
beds or shelves, one above another, of much larger dimensions than those at present
in use; these beds or shelves are so arranged that, after the proper temperature is
obtained by the burning of coal, coke, wood, or other fuel, such temperature will be
kept up by the burning of the sulphur contained in the ores or compounds while
passing over the shelves or beds, without any extra fuel. The hot gases or vapours
produced on the upper beds or shelves by the burning of the sulphur in the ores or
compounds, we convey by means of suitable flues and dampers or gates, under the
lower bed or shelves, for the purpose of heating the ores or compounds thereon, and
then by other flues into cooling chambers and condensers or vitriol chambers. When
necessary we convey the gases or vapours produced on the lower beds or shelves,
by means of separate flues and dampers or gates, into a condenser or condensers
without allowing them to come in contact with the ore treated or the gases
produced on the upper beds or shelves, so that any metals that may be volatilized
can be recovered, and the sulphuric or hydrochloric acid condensed. These acids
may be used for leaching the roasted ores or compounds.
After the bulk of the sulphur is burnt off on the upper beds and the ores or
compounds are passed down on to the lower beds or shelves, we close the gates or
dampers between the lower and upper beds or shelves, and, when necessary, we
introduce a quantity of common salt or other chloride or acid, or sulphate of iron
or other sulphate, or a mixture of these substances, and thoroughly mix the same
with the ores or compounds on the lower beds or shelves, so that the metals may be
all converted into chlorides or sulphates. The ores or compounds on the lower beds
or shelves are then drawn out of the apparatus, and may be smelted or leached, and
the metals precipitated by any well-known process.
In treating the second class of ores or compounds, after crushing or grinding
them, we pass them through an improved roasting or calcining furnace or apparatus
constructed with a number of horizontal beds or shelves, arranged one above
another, and communicating with one another by suitable channels; and adjoining
the beds or shelves, or under the bottom beds or shelves, we construct a chamber or
fire-place, which, when we desire to produce or recover free sulphur or sulphuric
anhydride, we keep filled with hot coke or other carbonaceous matter, or with
peroxide of iron. We connect with this chamber, another suitable chamber filled
with chequered or pigeon-holed brick-work. These chambers are so placed that,
after they have been heated to the required temperature, they will be kept hot by
the burning of the sulphur in the ores or compounds. If required, we use these
carbon or peroxide of iron chambers in treating the first class ores when we wish to
produce free sulphur or sulphuric anhydride.
The hot gases or vapours produced by the burning of the sulphur in the ores
on the upper shelves, we convey, by suitable flues provided with gates or dampers,
through the chamber containing the hot coke or other carbonaceous matter or
peroxide of iron, then through the chamber containing the chequered brick-work
(for the purpose of decomposing any compounds of sulphur with carbon, hydrogen,
or oxygen) and under the lower beds or shelves for the purpose of heating the
ores or compounds thereon, and then into cooling chambers, where the sulphur is
deposited and collected; or, when the first chamber is filled with peroxide of iron,
the gases, after passing through it, are passed through tubes cooled with water,
where the sulphuric anhydride is condensed and collected. The coke is kept hot
by being supplied with the air contained in the said hot gases or vapours, or, when
necessary, a small quantity of air is admitted to the chamber or fireplace for this
purpose.
To the lower beds or shelves of the furnace or apparatus we connect a separate
flue, with suitable gates or dampers, so that the gases or vapours produced on the
said lower beds or shelves may be conveyed into a separate chimney or condenser
(without coming in contact with the ore or gases on the upper.beds or shelves), so

page_text: that any metals which may be volatilized can be recovered, and the sulphuric acid
or hydrochloric acid condensed. When the ores or compounds have been suffi-
ciently roasted on the upper shelves and have been passed down on to the lower
beds or shelves, and the bulk of the sulphur has been burnt off, we add, if
necessary, a quantity of common salt or other chloride or acid, or sulphate of irou
or other sulphate, while the ores or compounds are maintained at the proper
temperature by the hot gases passing from the upper shelves under the lower
shelves or beds. The ores or compounds are thoroughly mixed with the salt or
chloride or acid or sulphate until all the metals are converted into chlorides or
sulphates. The ores or compounds are then drawn out of the apparatus, and may
be smelted or leached and the inetals recovered from the solutions and from the
residue by any well-known method or process.
In the accompanying drawings-
our
Figure 1 is a front view of an apparatus. constructed according to
improvements, one furnace being shown in elevation and another in vertical
section.
Figure 2 is a transverse section of the said apparatus on the line x, x, Figure 1.
Figure 3 is a transverse section of the said apparatus on the line x¹, x²,
Figure 1.
Figure 4 is a plan illustrating the arrangement of and mode of working the
cooling tubes and chambers, the condensers and the vitriol chambers.
Figure 5 is a section on the line y, y, Figure 4, and
Figure 6 is a section on the line y', y', Figure 4.
The improved furnace or apparatus consists of four or more vertical walls
supporting a number of horizontal shelves fixed at short distances apart, one
above another, and covered with an arched or flat roof, with our specially
arranged channels or flues and dampers or gates for separating the gases and
for passing the ores or compounds from one shelf to another, and for conveying
the heat produced on the upper shelves or beds underneath the lower shelves
or beds, and for passing the gases or vapours produced on the upper shelves
through hot carbonaceous matter, or through hot peroxide of iron and through
cooling chambers or condensers, and for passing the gases or vapours evolved on
the lower beds or shelves into separate condensers.
A, A indicate the improved furnaces, of which any desired number may be
employed, arranged side by side.
a, a are the horizontal beds or shelves of the furnace; b, bare the working
doors through which the stirring of the ore or the moving of the same from either
shelf to the shelf beneath may be accomplished by means of rakes or paddles,
worked either by hand or by mechanical appliances. c, e are dampers or gates
for closing the openings through which the roasted or chlorinated ore is passed
Into the vaults d. e, e are doors for permitting the withdrawal of the roasted or
chlorinated ore from the said vaults. f,fare plugs, lids or valves for closing the
openings or flues leading from the lower set of shelves or beds to the upper set
thereof, and also the central opening or flue leading from the lowermost shelf a
of the upper set to the shelf next above it. g, gare flues for conducting the hot
gases from the upper shelves or beds a into coke chambers or peroxide of iron
hambers h, or into channels or flues through which they pass into the space
underneath the lower shelves or beds a¹. g', g' are dampers for closing the said
lues g., h, are iron boxes used for charging coke or carbonaceous matter into
he chambers . j is the chequered brickwork under the lower shelves a', for
etaining the heat, and also for so mixing the sulphur and carbon, or sulphide of
arbon gases that the sulphur may be completely separated in the cooling and
epositing chambers hereinafter described. k is a flue for conveying the gases
volved on the upper shelves, after passing underneath the lower shelves, to
oolers and depositing chambers, or to vitriol chambers as required. is a channel
r flue for conveying the gases evolved or metals volatilized on the lower shelves
r beds a', into separate condensers or directly into a chimney if required.

page_text: m is an iron hopper for charging the regulated quantity of ore into the furnace.
n, n are flues leading from the carbon or peroxide of iron chambers h, to the
chequered brick-work p for decomposing the sulphur compounds. 9 is a flue
leading from the chequered brick-work p to a cooler, condenser, depositing chamber
or chimney as the case may be.
The horizontal shelves or beds a, a¹ arc, for certain classes of ores, made hollow,
so that coal-gas or petroleum may be burned in the space within them to maintain
the required temperature.
The chamber may be kept full of hot coke or carbonaceous matter or of
peroxide of iron, or may be left empty, as required, according to the different
classes of ores to be treated or to whether it is intended to recover the sulphur in
the form of sulphuric acid, sulphuric anhydride or free sulphur, or not to recover
the sulphur at all (if not required), or only to pass a part of the hot gases
under the lower shelves. The coke or carbon in the chamber is kept red hot by
the hot gases passing through it; this chamber is, however, only necessary when
it is desired to recover the sulphur as free sulphur.
Referring to Figures 4, 5 and 6, r, r indicate tubes which are kept cool with
water, and through which the gases or vapours evolved in the first stage of the
roasting are conducted, after they have passed through the hot peroxide of
iron in the chambers h, and in which the sulphuric anhydride is condensed and
collected. These tubes are not required when vitriol or free sulphur is to be
produced in place of the sulphuric anhydride.
8, s are cooling chambers in which the greater part of any metals that may have
been volatilized in the first stage of roasting are deposited and collected, and in which,
when necessary, we provide a number of horizontal or sloping shelves whereon we
place a layer of the roasted and moistened ore; over or through this layer of ore
we pass the sulphurous acid gas. The said ore we remove and replace with fresh
ore as required. Or the roasted and moistened ore may be caused to trickle down
the sloping shelves while the 'sulphurous acid gas is passing up through the
chambers s. The oxides of zinc and other metals absorb the sulphuric and part
of the sulphurous acid, forming sulphates or sulphites, while any metals that may
have been volatilized are deposited on the damp or moistened ore.
s', are condensers in which the remainder of the metals that may have been
volatilized or evolved in the first stage of roasting are condensed and collected.
These condensers are packed with bricks or coke or other suitable material, and,
when necessary, water or sulphuric acid is kept percolating down the same, while
the sulphurous acid gas is passing through them.
t is a tower packed with coke or other suitable material, through which the
sulphurous acid gas and steam pass, after leaving the condensers s', while strong
sulphuric acid containing nitrous acid is kept percolating down. The nitrous acid
is thus liberated, and passes, along with the sulphurous acid, through a flue t³, into
vitriol chambers u, wherein the sulphurous acid, by the action of the nitric acid,
steam and air, is converted into vitriol or sulphuric acid. The gases not con-
densed in these chambers are then passed through a flue u¹ into and through a
tower packed with coke or other suitable material, and through which strong
sulphuric acid is kept percolating, which absorbs all the nitrous acid. This tower
is connected by a flue with the chimney o, which, if made of suitable dimensions,
will produce sufficient draught to draw the gases from the furnaces through the
whole apparatus. If necessary, however, exhausting fans may be used to create
sufficient draught.
83, 83 are cooling chambers, which are partly filled or packed with bricks or
other suitable material, and through which the gases or vapours evolved in the
first stage of roasting may be conducted, after passing through the hot coke or
carbonaceous matter and through the chequered brickwork and then through
the cooling chambers s, and in which the free sulphur will be condensed and
collected. These chambers are also connected, by means of a flues, with the
chimney o, for the purpose of drawing the gases or vapours from the furnaces

page_text: through the cooling and condensing apparatus. These chambers are not required
when producing vitriol.
3,83 are condensers packed with bricks or coke or other suitable materials, and
through which the gases or vapours evolved on the lower beds or shelves are
passed, while water or dilute acid is kept percolating down through them, and
in which the volatilized metals and any hydrochloric or sulphuric or sulphurous
acid or chlorine or chlorides are condensed, the same being collected in the
tanks v.
, ware nitre-pots placed over the flue k, and used for generating nitric acid
vapour, which is conveyed by the flues w¹, t, into the vitriol chamber to along
with the sulphurous acid, for the purpose of converting it into sulphuric acid.
», are tanks for receiving the acids from the absorbing and denitrating
towers t and t¹; v2, v² are tanks for receiving the acid liquors or metals condensed
in the condensers s'; v³, are tanks or vessels for receiving the sulphur condensed
in the chambers s'.
According to the class or grade of ores or compounds to be treated, we, as above
stated, vary the process and apparatus which we employ. In treating the first-
class ores or compounds, we first crush or grind them, and then place the fine ore in
the charging hopper m. We then burn a small quantity of coal, coke, wood or other
fuel under or on the bottom shelf or bed a', until the upper shelves are brought to
a good red heat. We then open the valve in the charging hopper m so as to allow
sufficient ore to pass on to the upper shelf to cover it to a depth of from two to
four inches. We then spread the ore evenly over the shelf, and stir it well
every hour, or oftener if required, for from four to twelve hours, according to
the quality of the ore. We then pass the ore on to the second shelf and put
a fresh charge on the top shelf, and, after spreading the ore evenly over the
shelves and well stirring or turning over the ore on both shelves every hour or so,
for from four to twelve hours, we then pass the ore from the second shelf on to the
third shelf, and pass the ore from the top shelf on to the second shelf, and then put
a fresh charge on the top shelf, and continue in this way moving the ore at regular
intervals from one shelf to another lower shelf until all the shelves are full, except
the lowest one.
We then stop using fuel and close the two side plugs or lids fon
No. 5 shelf, and to the ore on No. 6 shelf, when it requires chlorinating, or when
the metals require more completely converting into sulphate, we add a small
quantity of common salt or other chloride or hydrochloric or sulphuric acid, or
chlorine or sulphate of iron, or other sulphate, or a mixture of these substances,
as may be necessary, and thoroughly mix the same with the ores or compounds
by stirring with rakes or paddles introduced through the doors b, and actuated
either by hand or by mechanical appliances at intervals of one hour or so, for
from four to twelve hours, according to the quality of the ores.
We then pass
the ore from No. 6 on to No. 7 bed or shelf and then close the plug f on the
centre of No. 4 shelf and open the two side plugs fon No. 5 shelf, and then pass
the ore from No. shelf on to No. 6 shelf; then close the two side plugs ƒ on
No. 5 shelf and open the plug on the centre of No. 4 shelf; we then pass the
ore from each of the upper shelves on to a lower shelf. Then to the ore on
No. 6 shelf, when required, we add a small quantity of common salt or other
chloride or acid, or chlorine, or sulphate of iron or other sulphate, or a mixture of
these substances as before, and keep the ore on all the shelves stirred every hour or
so for from four to twelve hours. The ore on the lowermost shelf we then draw
through the dampers or gates c into the vaults d, and then go on repeating the
charging, moving and stirring of the ore and the mixing thereof with salt or the
like, at regular intervals, as above described. The roasted or chlorinated ore is
then removed, and leached or smelted as required.
The sulphur in the ore while passing over the upper shelves is oxidized or burnt,
and produces sufficient heat to keep the lower shelves hot. The hot sulphur or
sulphurous acid gas or vapour is, for this purpose, conveyed by the flues or
channels g, through the chambers h, and flues i, and through the chequered brick-

page_text: work into the flue k, whence it is conducted into cooling or depositing chambers
and sors, being mixed, when required, with nitric acid fumes and steam and
passed into vitriol chambers u.
The sulphur may be recovered as free sulphur from the cooling and depositing
chambers s, if the hot gas has passed through the hot carbonaceous matter and
chequered brick-work; or as sulphuric anhydride in the tubes r, if the sulphurous
acid gas has passed over the hot peroxide of iron. In the vitriol chamber u, the
sulphur is recovered as sulphuric acid. The hot sulphurous acid produced on the
upper beds or shelves, passing through the channel and brick-work j, maintains
the ore on the lower shelves at a dull red heat, so that, when the common salt or
other chloride, acid or chlorine or sulphate of iron or other sulphate, or mixtures
of these substances are added, the metals contained in the ores or compounds are
converted into chlorides or sulphates. The gases or vapours evolved on the two
lower shelves a are conveyed by the channel or flue into a condenser s³ where all
the hydrochloric acid, sulphuric acid, chlorine, and volatilized metals are completely
condensed, the same being collected in the tanks v. The acid liquor produced in
the condenser and containing the volatile metals is then used for washing
the roasted ore, so that the metals in it can be precipitated along with the
metals contained in the ore, or they may be precipitated separately, when
required.
When treating second-class ores, the charging, stirring, and moving of the ore
from one shelf on to another is carried out as above described, only without
adding salt or the like to the ore on No. 6 shelf. According to the nature or
quality of the ores to be treated, we vary the weight of the ore charged and
the intervals of charging; and we also vary the number of shelves in the furnace,
and the position of the plugs or lids, that is to say, we put them on a shelf or two
higher or lower as required. With ordinary ores or compounds, one of our
improved double furnaces or apparatus will roast or calcine and chlorinate
100 tons per week, without any extra or additional fuel except what is required in
starting. When we desire to recover the sulphur contained in the ore or com-
pounds in the form of sulphuric acid, we simply pass the hot sulphurous acid gas
produced on the upper shelves through the chanuel g, and down through the
chamber h, without contact with carbonaceous matter, then through the flue i and
through the brick-work j under the lowermost bed or shelf a' and then over the
nitre-pots to which give off nitric acid vapour, and through the cooling and
condensing chambers 8, s¹, and then into an ordinary vitriol or lead chamber u,
into which a jet of steam is introduced, and in which the sulphuric acid is
collected.
If we desire to recover the sulphur contained in the ores or compounds in the
form of free sulphur, we keep the chambers full of coke or carbonaceous matter,
and pass the hot sulphurous acid gas through the channels g, and through the
chambers containing the carbon, which is kept red hot by the hot gases passing
through it, and then through the channel i and through the chequered brick-work j
under the lowermost shelf, or through the channels n, Figure 3, and through the
chequered brick-work p (if all the heat is not required under the lower bed), and
then into cooling and depositing chambers s and s², from which the free sulphur
is removed as required.
are
If the sulphur is to be recovered as sulphuric anhydride, the chambers
filled with peroxide of iron, and the hot sulphurous acid gas produced on the upper
shelves is passed through the channels g, and through the peroxide of iron in the
chambers, and then through the channels and chequered brick-work ; (or
through the flues n if all the heat is not required under the lower shelf) and
then into the cooling tubes r, from which the sulphuric anhydride may be withdrawn
as it accumulates.
When the ores or compounds are of such a nature that, after they are roasted
and moistened and exposed to the action of the sulphurous acid gas (produced in
roasting the ores), they will condense or retain any volatilized metals and absorb

page_text: sufficient sulphurous and sulphuric acid to convert the metals or metallic oxides
into sulphites or sulphates, then, unless it is intended to produce vitriol, sulphur
or sulphuric anhydride for sale or for other purposes, all the condensers, cooling
tubes and vitriol chambers may be dispensed with, and the gases evolved or metals
volatilised on the lower shelves of the improved furnace may then be allowed to
pass over the ore on the upper shelves and to mix with the gases or vapours
produced thereon and pass through the channel g, flue i and chequered brick-work j
to the flue and thus into the cooling chambers. The roasted ore, after
absorbing the sulphurous acid and other substances in the chambers 8, would then
be leached with water and a little acid, if necessary, and the metals precipitated or
recovered from the solutions obtained, and the residue smelted or treated by any
well-known method or process for extracting the metals therefrom.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we wish it understood that
we do not claim generally or irrespectively of our improvements hereinbefore
described, the use of furnaces having horizontal beds or shelves arranged one above
another, as we are aware that such furnaces have been used for roasting or
calcining ores; but we are not aware that such furnaces have heretofore been
constructed in such a manner that the heat produced on the upper shelves could be
conducted beneath the lower shelves and the gases or vapours evolved on the upper
and lower shelves could be separately collected and condensed; and we declare
that what we claim is ;-
First. In the roasting or calcination of ores or compounds containing metals and
sulphur, the utilization of the heat produced by the burning or oxidation of the
sulphur contained in portions of the ores or compounds under treatment, for
maintaining the heat required to effect the roasting or calcination of other portions
of such ores or compounds, with or without the use of extra or additional fuel,
substantially as hereinbefore described.
Second. The treatment of ores or compounds containing metals and sulphur, by a
process wherein the sulphur burnt off from the ores or compounds in one stage of.
the process is utilized for maintaining the heat in a succeeding stage thereof, and
the gases or vapours evolved in these two stages are separately collected and
condensed, for the purposes above specified.
Third. The treatment of ores or compounds containing metals and sulphur, by a
process in which the sulphur contained in the said ores or compounds is oxidized or
burnt and from a part of the resulting gas or vapour the sulphur is recovered as
sulphuric acid, sulphur or sulphuric anhydride, whilst the other part thereof
combines with the metals to form sulphates, the heat produced by the oxidation of
the sulphur in the first stage of the process being utilized to maintain the required
temperature in a succeeding stage thereof, substantially as herein before described.
Fourth. The improved process of treating ores or compounds containing metals
and sulphur, consisting in roasting or calcining and chlorinating or sulphatizing the
said ores or compounds, recovering the greater proportion of the sulphur therefrom
either as free sulphur or as sulphuric anhydride or as sulphuric acid, and
condensing and recovering the volatilised metals, substantially as hereinbefore
described.
Fifth. In a process such as we have hereinbefore described, the conversion of
the oxide of zinc or other oxides in the roasted and moistened ore into sulphates or
sulphites, by passing the sulphurous acid gas over or through such ore, sub-
stantially as herein before described.
Sixth. A roasting or calcining furnace so constructed that the hot gases or
vapours from the upper beds or shelves can be passed under the lower beds or
shelves to maintain the heat thereof, substantially as hereinbefore described.
Seventh. A roasting or calcining furnace having beds or shelves arranged one
above another and provided with flues or passages for conducting the gases or
vapours therefrom into coolers, condensers or vitriol chambers, and with dampers,
B

page_text: gates or valves for controlling the flow of the said gases or vapours, so that the
gases or vapours produced on the upper beds or shelves and those produced on the.
Tower beds or shelves may be separately collected and condensed, for the purpose
above specified.
Eighth. The improved furnace constructed substantially as described with
reference to Figures 1, 2, and 3 of the drawings, for the purposes above specified.
Ninth. The modification of our improved furnace wherein we employ hollow
beds or shelves arranged to be heated internally, substantially as hereinbefore
described.
Tenth. The combination of the roasting or calcining furnaces, and the coolers,
condensers and vitriol chambers connected therewith, substantially as described
with reference to Figures 4, 5 and 6 of the drawings, for the purposes above
specified.
Dated the 4th dox of January 1893
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.