Improvements in the Roasting of Sulphide Ores and Mattes.
Year: 1895

page_text: Date of Application; 11th Nov., 1895
Complete Specification Loft 11th Aud 1836 Accepted 19th Sent
1806
Date of Application; 11th Nov., 1895
Complete Specification Loft 11th Aug 1838_Accepted 19th Sent
1806
PROVISIONAL SPECIFICATION.
Improvements in the Roasting of Sulphide Ores and Mattes.
I, CARL FRIEDRICH CLAUS, of 88 Yeldhain Road, Hammersmith, in the County
of Middlesex, Chemist, do hereby declare the nature of this invention to be as
follows:
My invention consists in an improved method or process of roasting sulphide
ores whereby the sulphides are converted into sulphates. Some of the sulphates
thus formed are soluble and may be obtained in solution by leaching, others being
insoluble remain with the other insoluble residue.
The said method of roasting is also applicable to ores or to mattes containing
mixtures of metallic sulphides and metallic oxides.
My invention has for its object to bring, during the roasting process, the whole
or most of the bot sulphurous acid produced by the oxidation of the sulphur
contained in that portion of the ore-charge which was last introduced into the
furnace, together with air, which is mixed with a regulated quantity of steam, into
intimate contact with the other parts of the ore-charge (which have already been
partly or wholly roasted) in order to convert the oxides or any unoxidised sulphides
in the same, into sulphates.
For this purpose I admit the air together with some steam in such a manner that
part of it comes into contact with the ore which was last introduced into the
furnace or kiln and which still contains the whole or nearly the whole of its
sulphur, and the gases resulting from the roasting of this ore pass through the mass
or body of the ore which is already wholly or partially roasted. Although I may
thus in the continuous working of the furnace admit the whole of the necessary
air at the place where the furnace is charged with fresh ore, I prefer to provide for
admitting the air at various parts or zones of the ore-charge, which are at different
stages of ronsting.
My improved roasting process will be readily understood from the following
description of the same as carried on in a vertical furnace (such as a shaft-furnace
or kiln) closed at the top with the exception of an opening (which can be closed at
will by a valve or door) through which it is fed with the orc.
On one or more sides of the furnace and at various heights are apertures through
which an abundant supply of air can be forced in by a fan or like appliance, or
drawn in by chimney-draught.
In this manner the supply of cold or heated air is divided up into a number of
currents, which, passing through the apertures above mentioned, are caused to
travel, together with the sulphurous acid formed during the roasting (and, when
fuel is being used, with the products of the complete combustion thereof),
continuously in a downward direction through the mass of the ore and in direct
contact with it, that is to say, in the direction from the last charge of ore to the
charge.which, has been longest in the furnace. In a vertical. furnace, this would
mean from the top to the bottom. Thence the gases are conveyed away through
an opening or flue."
The ore is fed into the furnace in pieces of suitable size. It may, if desired, be
previously partly roasted and pulverised. Such ore as well as other pulverulent
ores, smalls, concentrates and slines are mixed with clay and moulded so as to form
suitable pieces.

page_text: By regulating the air supply to the apertures at different heights in the side of
the furnace, I can roast the ore in such a manner that at the bottom of the furnace
it is wholly oxidised or converted into sulphates, while at the same time the portion
charged last into the furnace is comparatively little acted upon, so that there are
zones or strata of ore in different stages of progress towards complete oxidation
and this condition of the various strata may he maintained, while the furnace is
repeatedly charged and discharged.
In cases in which the ore contains an insufficient quantity of sulphur to maintain
the necessary beat, heated air or hot fuel-gases of a sufficiently oxidising character
may be introduced along with the air.
Steam is admitted with the air into the roasted or partly roasted ore in suitably
regulated quantities.
The completely roasted ore is withdrawn from the bottom of the furnace through
a suitable opening capable of being closed by a door.
Instead of a vertical furnace which I have described for purpose of illustration,
I use, by preference a horizontal furnace divided by partition walls into a number
of chambers or compartments which may be considered to represent the different
zones or strata of the vertical furnace.
Each of these compartments can be supplied with regulated quantities of air
or of air and steam through suitable pipes as may be required. Hot fuel' gases of
an oxidising character may also be used if required.
Each compartment is connected with the one following and the one preceding it
by valved passages,, so that the supplied air and the sulphurous acid and other
products of combustion can be passed in a continuous current through the mass of
ore in any desired number of the said chambors. The air, sulphurous acid and
other products of combustion pass from each chamber to the next in order, from
that last charged with ore to that in which the charge has been longest acted on in
the furnace. The current of the gases in each chamber is, by preference, from the top
towards the bottom. It then rises from the bottom through a valved flue to the
top of the next chamber whence, accompanied by an additional supply of air or of
steam and air, it passes through the mass of ore in the next chamber; and so on
through the series of chambers, to be conveyed away from the last charged chainber
by a suitable pipe or flue.
When the roasted ore is discharged from the last chamber of the series, this
chamber is recharged with fresh ore, becoming then the first, while the last
but one becomes the last. It in its turn becomes the first and so on in rotation.
By opening or closing the valves as required, each compartment of the series can
in turn be made the first, the last or an intermediate one.
It is obvious that my method of roasting sulphide ores, may be carried out in
many different forms of furnace.
Dated the 11th day of November 1895
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Roasting of Sulphide Ores and Mattes.
1, CARL FRIEDRICH CLAUS, of 88 Yeldham Road, Hammersmith, in the County
of Middlesex, Chemist, 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:-
My invention consists in an improved method or process of roasting sulphide

page_text: ores whereby the sulphides are converted into sulphates. Some of the sulphates
thus formed are soluble and may be obtained in solution by leaching, others being
insoluble remain with the other insoluble residue.
The said method of roasting is also applicable to ores or to mattes containing
mixtures of metallic sulphides and metallic oxides.
My invention has for its object to bring, during the roasting process, the whole
or most of the hot sulphurous acid produced by the oxidation of the sulphur
contained in that portion of the ore-charge which was last introduced into the
furnace, together with air, which, in some cases is mixed with a regulated quantity
of steam, into intimate contact with the other parts of the ore-charge which have!
already been partly or wholly roasted, in order to convert the oxides or any
unoxidised sulphides in the same, iuto sulphates.
For this purpose I admit the air (together with some steam if thought desirable)
in such a manner that part of it comes into contact with the ore which was last
introduced into the furnace or kiln and which still contains the whole or nearly the
whole of its sulphur, and the gases resulting from the roasting of this ore pass
through the mass or body of the ore which is already wholly or partially roastcil.
Although I may thus in the continuous working of the furnace admit the whole of
the necessary air at the place where the furnace is charged with fresh ore, I prefer
to provide for admitting the air at various parts or zones of the ore-charge, which
are at different stages of roasting.
The manner in which my invention is carried into practice will be readily
understood by reference to Figures 1 and 2 of the accompanying drawing.
These figures represent a vertical furnace (such as a shaft-furnace or kiln) closed
at the top with the exception of an opening a (which can be closed at will by a
valve or door) through which it is fed with the ore.
On one or more sides of the furnace and at various heights are apertures (such,
for instance as are shown at b, c, d and e) through which an abundant supply of air
can be forced in by a fan or like appliance, or drawn in by chimney-draught.
In this manner the supply of cold or heated air is divided up into a number of
currents, which, passing through the apertures above mentioned, are caused to travel,
together with the sulphurous acid formed during the roasting (and, whon fuel is
being used, with the products of the complete combustion thereof), continuously in
a downward direction through the mass of the ore and in direct contact with it,
that is to say, in the direction from the Jast charge of ore to the charge which has
been longest in the furnace. In a vertical furnace (such as shown in Figures 1
and 2 of the drawing) this would mean from the top to the bottom. Thence the
gases are conveyed away through an opening.or flue f.
The ore is fed into the furnace in pieces of suitable size; it may, if desired, be
previously partly roasted and pulverised. Such ores, as well as other pulverulent
ores, smalls, concentrates and slimes are mixed with clay and moulded so as to form
suitable pieces.
By regulating the air supply to the apertures at different beights in the side of
the furnace, I can roast the ore in such a manner that at the bottom of the furnace
it is wholly oxidised or converted into sulphates, while at the same time the portion
charged last into the furnace is comparatively little acted upon, so that there are
zones or strata of ore in different stages of progress towards complete oxidation,
and this condition of the various strata may be maintained, whilst the furnace is
repeatedly charged and discharged.
In cases in which the ore contains an insufficient quantity of sulphur to maintain
the necessary heat, heated air or hot fuel gases of a sufficiently oxidising character
may be introduced along with the air.
It is also found of advantage in this mode of roasting to convey steam along with
the air into the furnace.
7
'
The completely roasted ore is withdrawn from the bottom of the furnace through'
an opening g capable of being closed by a door.

page_text: Instead of a vertical furnace which I have described for purpose of illustration,
1 use, by preference, a horizontal furnace such as is shown in Figures 3, 4
and 5, divided by partition walls into a number of chambers or compart-
ments A¹, A²,
A*, which may be considered to represent the different zones
or strata of the vertical furnace.
Ench of these compartments can be supplied with regulated quantities of cold or
heated air or of air and steam (as shown for instance in Figure 3) from the pipe B
through the pipes B¹, B³,
B*. Hot fuel gases of an oxidising
character may also be used if required.
Each compartment as A', A³,".
.
A is connected with the one following
and the one preceding it by valved passages D', D'.
. . Dx, so that the
supplied air and the sulphurous acid and other products of combustion can be
passed in a continuous current through the mass of orc. in any desired number of
the said chambers. The air, sulphurous acid and other products of combustion
pass from each chamber to the next in order, from that last charged with ore
towards that in which the charge has been longest acted on in the furnace. The
current of the gases in each is, by preference, from the top towards the bottom.
It then rises from the bottom through the apertures a, a, a, a and through the
valved flue to the top of the next chamber, whence, accompanied by an additional
supply of air or of steam and air, it passes through the mass of ore in the next
chamber, and so on through the series of chambers, to be conveyed away from
the last charged chamber by one of the branch-pipes F¹, F*..
F** and the
pipe or flue F.
. •
"
When the roasted ore is discharged from the last chamber of the series, this
chamber is recharged with fresh ore, becoming then the first, while the last but one
becomes the last. It in its turn becomes the first and so on in rotation. Thus (in
reference to the drawing) if for example the chamber A had been the first
charged of the series and if in it the ore is completely roasted, the gases from it are
allowed to flow through the branch pipe F into the discharge pipe F. In
the meantime the compartment A is recharged with fresh ore whilst the oxidised
ore is removed from the compartment A.
By opening or closing the valves C, E and G as required, each compartment
of the series can in turn be made the first, the last or an intermediate one.
It is obvious that my method of roasting sulphide ores, may be carried out in
many different forms of furnace; noue of which forms do I claim as any part of my
present invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
First. The herein described process of roasting sulphide ores, according to which
the air or steam and air required for the oxidation of the sulphides into oxides and
sulphates is supplied in separate currents to various zones or struta of the ore-
charge, and is made to pass, together with the sulphurous acid and other products
of combustion, in a continuous current through the body of ore from that last
charged to, through and out of the charge which bas been longest in the furnace.
Second. The herein described process of roasting sulphide ores, according to
which cold or heated air, with or without steam, is continuously passed through the
ore in a furnace or kiln in such a manner that, after passing through that part of
the ore which has been last charged, it, along with the sulphurous acid' formed,
passes through and acts upon the parts of the ore that have already been partially
or wholly roasted.
Third. The roasting of sulphide ores by a process according to which a supply
of air or of steam and air sufficient for the oxidation of the sulphides into oxides
and sulphates, is directed into different parts of the ore-charge which are at
different stages of roasting, and flows together with the sulphurous acid and other

page_text: products of combustion in a direction from the less roasted ore to and through the
ore that has been longest in the furnace, for the purpose above specified.
Dated this 11th day of August 1896.
D. Young & Co.,
C. CLAUS.
11 & 12 Southampton Buildings, London, W.C.,.
Agents for the Applicant.