IMPROVEMENTS IN THE PROCESS AND APPARATUS FOR CALCINING SULPHIDE ORES OF COPPER AND OTHER METALS."
Year: 1881

page_text: "
LETTERS PATENT to Robert Mackenzie, of La Puebla de Guzman, in the
Province of Huelva, Spain, at present of No. 28, Southampton Buildings, in
the County of Middlesex, for an Invention of IMPROVEMENTS IN THE
PROCESS AND APPARATUS FOR CALCINING SULPHIDE ORES OF COPPER AND
OTHER METALS."
PROVISIONAL SPECIFICATION left by the said Robert Mackenzie at the
Office of the Commissioners of Patents on the 11th October 1881.
ROBERT MACKENZIE, of La Puebla de Guzman, in the Province of Huelva,
Spain, at present of No. 28, Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN THE PROCESS AND APPARATUS FOR CALCINING SULPHIDE
ORES OF COPPER AND OTHER METALS."
My Invention relates to a process and apparatus for continuously roasting or
calcining sulphide ores of copper and other metals, whereby I am enabled to
abridge considerably the time occupied and to diminish the labour required, as also
to obviate the inconvenience and nuisance resulting from the fumes evolved in the
process as it is usually conducted. For this purpose I effect the roasting in a closed
furnace, which is fed by a hopper at the top and from which the roasted
material is withdrawn by inclined lateral shoots at the bottom. While the
material is roasting I cause steam to pass through it. This may be done by
introducing steam from an extraneous source at the bottom of the furnace, or by
causing water to trickle over inclined surfaces at the bottom. I prefer, however,
for simplicity of construction and action, to place at the bottom of the furnace a
shallow tank, which I keep supplied with water. The steam generated from this
water by the heat of the roasting material above rises through the body of ore in
the furnace and greatly accelerates the roasting process. The fumes rising from
the roasting material are conveyed from the upper part of the furnace by a lateral
flue to a condenser of any known kind. A convenient method of condensing is to

page_text: lead the fumes to the top of a vertical tower or column in which a shower of water
is caused to descend along with the fumes, which are finally drawn through water
at the bottom by an ejector or exhauster. The ore at the upper part of the furnace
may in some cases have water discharged in a shower upon it. The furnace tank
above mentioned is kept supplied with a surplus of water, so that there is always
a little overflow of hot water charged with products from the calcined ore.
This
water, or that flowing from the bottom of the tower or column, may be used to
moisten heaps of ore for lixiviation and also in the precipitating tanks, so as to
economise the consumption of iron therein; also the fumes that enter the tower or
column, and which contain a large proportion of sulphurous acid, may be treated
in the known manner for the production of sulphuric acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Robert Mackenzie in the Great Seal Patent Office on the 11th
April 1882.
ROBERT MACKENZIE, of La Puebla de Guzman, in the Province of Huelva,
Spain, at present of No. 28, Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN THE PROCESS AND APPARATUS FOR CALCINING SULPHIDE
ORES OF COPPER AND OTHER METALS."
My Invention relates to a process and apparatus for continuously roasting or
calcining sulphide ores of copper and other metals, whereby I am enabled to
abridge considerably the time occupied and to diminish the labour required, as also
to obviate the inconvenience and nuisance resulting from the fumes evolved in the
process as it is usually conducted. For this purpose I effect the roasting in a closed
furnace, which is fed by a hopper at the top and from which the roasted material
is withdrawn by inclined lateral shoots at the bottom. While the material is
roasting I cause steam to pass through it. This may be done by introducing steam
from an extraneous source at the bottom of the furnace, or by causing water to
trickle over inclined surfaces at the bottom. I prefer, however, for simplicity of
construction and action, to place at the bottom of the furnace a shallow tank, which
I keep supplied with water. The steam generated from this water by the heat of
the roasting material above rises through the body of ore in the furnace and
greatly accelerates the roasting process. The fumes rising from the roasting
material are conveyed from the upper part of the furnace by a lateral flue to a
condenser of any known kind, or to an apparatus for producing sulphuric acid.
A convenient method of condensing is to lead the fumes to the top of a vertical
tower or column in which a shower of water is caused to descend along with the
fumes, which are finally drawn through water at the bottom by an ejector or
exhauster. The ore at the upper part of the furnace may in some cases have water
discharged in a shower upon it. The furnace tank above mentioned is kept
supplied with a surplus of water, so that there is always a little overflow of hot
water charged with products from the calcined ore. This water, or that flowing
from the bottom of the tower or column, may be used to moisten heaps of ore for
lixiviation and also in the precipitating tanks, so as to economise the consumption
of iron therein; also the fumes that enter the tower or column, and which contain
a large proportion of sulphurous acid, may be treated in the known manner for
the production of sulphuric acid.
The apparatus which I employ may be varied in form and proportions; I will,
however, for the sake of clearness of explanation, describe one form, as shown in
the accompanying Drawings. Fig. 1 is a transverse section, Fig. 2 is a longitudinal
section, and Fig. 3 is a plan on X, X, of a roasting or calcining furnace arranged
according to my Invention. The furnace is of brickwork or masonry A, preferably
strengthened by exterior iron bands or casing, and somewhat contracted about the
middle of its height, as at a. It is fed with ore introduced by a hopper B at the
top, and the ore as it descends is roasted, the calcined material being withdrawn
from time to time into trucks by inclined shoots C furnished with doors. On the
bed of the furnace I place a shallow tank D, which I keep supplied with water
introduced by a pipe, and in order to ensure the constant presence of water I
supply it somewhat in excess, so that there is always a little overflow by another
pipe. Part of the tank D may be occupied by a pyramid d of open brickwork.
The steam generated from the water in the tank D by the heat of the material
roasting above rises through the body of ore in the furnace and greatly accelerates
the roasting process. The fumes rising from the roasting material are conducted
from the upper part of the furnace by one or other, or by both, of two lateral

page_text: flues E, in each case to the upper part of a vertical shaft or tower F, in which a
shower of water is caused to descend with the fumes, which are finally drawn
through water at the bottom by the draught of an ejector or exhauster. In some
cases a little water may be discharged on the ore at the top of the furnace. Each
of the shafts or towers F may have flues E communicating with furnaces at both
sides of them, as indicated in Fig. 3, so that either or both of these furnaces may
deliver their fumes into either or both of the shafts adjoining them. The flues E
should also have valves or dampers, so that the communication with either furnace,
or with both, may be closed for cleansing or repair. The overflow water from the
tanks D, as well as that from the bottoms of the shafts F, may be used to moisten
heaps of ore for lixiviation, or it may be employed in the precipitating process, in
which its use will greatly economise the consumption of iron. As the fumes
contain a large proportion of sulphurous acid they may be treated in the shafts F
for the production of sulphuric acid by any of the known processes for that
purpose. When the ore treated contains volatilisable metals these passing off with
the fumes become condensed in the shafts.
Although I have described the arrangement of a water tank D as being a simple
method for producing the steam to rise through the ore obviously instead of this
arrangement steam from an extraneous boiler might be introduced by a pipe at the
lower part of the furnace with a like effect on the ore roasting above; or the water
instead of being supplied to a shallow tank might be made to trickle over inclined
surfaces at the bottom of the furnace.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,-
First. In the process of calcining sulphide ores, introducing steam at or near the
bottom of the mass of ore under treatment in a closed furnace or kiln, substantially
as and for the purposes herein set forth.
Second. In a calcining kiln or furnace for roasting sulphide ores, the use of
a tank supplied with water for generation of steam at or near the bottom, sub-
stantially as herein described.
In witness whereof, I, the said Robert Mackenzie, have hereunto set my
hand and seal, this Seventh day of April, in the year of our Lord One
thousand eight hundred and eighty two.