IMPROVEMENTS IN THE TREATING OR REDUCING OF COPPER ORES, AND IN THE CONSTRUCTION OF FURNACES FOR HEATING SUCH ORES, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER ORES
Year: 1843

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, EDWARD
BUDD, of Haford Copper Works, near the Town of Swansea, in the County of
Glamorgan, Copper Merchant, and WILLIAM MORGAN, of the same Place,
Refiner of Copper, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-eighth day of December, in the seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Edward Budd and William Morgan, Her especial license, full power,
sole privilege and authority, that we, the said Edward Budd and William
Morgan, our exors, admors, and assigns, or such others as we, the said
Edward Budd and William Morgan, our exors, admors, or assigns, should at
any time agree with, and no others, from time to time and at all times during
the term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, our Invention of "IMPROVEMENTS IN THE TREATING OR REDUCING OF
COPPER ORES, AND IN THE CONSTRUCTION OF FURNACES FOR HEATING SUCH ORES,
PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER ORES;" in which said
Letters Patent is contained a proviso that we, the said Edward Budd and
William Morgan, or one of us, shall cause a particular description of the
nature of our said Invention, and in what manner the same is to be performed,
to be inrolled in Her said Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
Edward Budd and William Morgan, do hereby declare that the nature of our
said Invention, and the manner which the same is to be performed, are fully
described and ascertained in and by the following statement thereof, reference
being had to the Drawings hereunto annexed, and to the figures and letters
marked thereon (that is to say):-
In order that our Invention may be fully understood, we will shortly state
the means now resorted to when treating copper ore, and then describe the
improvements which constitute the Invention secured by the present Letters
Patent.
Copper ores for the most part consist of sulphuret of copper, combined with
a large proportion of iron, various other metals in small proportions, and earthy
matter in which silica generally predominates, and the processes adopted for the
reduction of copper ores are adapted to the treatment of sulphurets of copper;
and copper ores, consisting of copper in other states of combination, such as
carbonates and oxides, are generally mixed in the furnace with sulphurets for
the purpose of their reduction. Copper ores are commonly subjected to the
following processes:-The ore is placed in a reverberatory furnace called a
calciner, where it is exposed to the action of a moderate degree of heat, not
sufficient for fusion, but sufficient for the volatilazation of a portion of the
sulphur. The result of this process is, that a considerable portion of the
surphur is driven off, and oxygen, derived from the atmospheric air, takes its
place chiefly in combination with the iron. The next process is that of
melting. This operation is performed in a reverberatory furnace, in which a great
heat is applied, as is well understood. The effect of this process is, that the cal-
cined ore being melted, the silica and other earthy matter, with the oxide of iron,
form a slag, and, being lighter than the metallic part of the ore, floats on the
surface, and is skimmed off by the workmen with a tool called a rabble. The
metallic part is then tapped or run off either into water which granulates it, or
into beds of sand forming pigs of metal. When tapped into sand, and thereby
formed into pigs, the pigs are subjected to another melting, as is well under-
stood, in a similar furnace; a surface of slag is again skimmed off, and the
metal is tapped into water and granulated. We prefer, however, the plan of
tapping at once into water, and granulating the metal at the first melting.
The granulated metal thus obtained is subjected to a process of calcination
similar to that adopted in the first instance with the ore, the result being
a further liberation of sulphur, and a further combination of oxygen with the
iron, and also to a certain extent with the copper; and when the process
is continued for a long period, a certain portion of copper also assumes the

page_text: shape of sulphate of copper; this is produced by an oxidation of sulphur and an
oxidation of copper, and a combination of the two. The metal thus calcined
is melted in a similar furnace, and by a similar process to that adopted for the
melting of the calcined ore, but a longer time is generally occupied in the
melting. A slag is skimmed off the surface, and the metal is tapped into water
or beds of sand. The melting process is repeated if the metal has not reached
the requisite degree of fineness, and occasionally the calcination is repeated.
When the metal has been brought to the state known in the trade as white
metal or pimpled copper, it is again melted in a reverberatory furnace called a
roaster, similar in construction with the melting furnaces employed in the
former meltings, with this difference, that a current of cold air is generally
admitted, and passed over the surface of the charge during certain periods of
the melting, when it can be done without reducing the temperature too low to
ensure the melting. This current of cold air is generally admitted through an
aperture in the corner of the furnace or at the top, and the object of its
admission is the oxidation of the remaining sulphur, and of foreign metals
which may be mixed with the copper, so as to purify the copper. The sulphur
goes off, and the foreign metals and earths form a slag on the surface, and are
skimmed off; a portion of the copper is also oxydised in this process, and is
skimmed off as part of the slag. The metal, which is very nearly pure copper,
say from ninety to ninety-five per cent., is then tapped into sand and run into
the shape of pigs. We have thus given a general outline of the processes
adopted for the smelting of copper ores. These processes by different manu-
facturers differ slightly in the details, and there are variations in the processes,
as are well known, when it is desired to produce copper of different qualities.
The process which remains is that of refining, which is conducted in a reverbe-
ratory melting furnace of similar construction with those used in the former pro-
cesses, and the object is to complete the purification of the copper, and to render
it in a condition to be applied to the purposes of manufacture. In the processes
usually adopted at present the atmospheric air finds its way into the calcining
furnaces through the holes in the doors of the furnaces and by other openings,
and enters cold into the furnace; a portion also finds its way through the fire-
places by means of the draught being too rapid to allow of the entire con-
sumption of the air passing through over the fuel. In the roaster the air is
admitted cold through the apertures before described. A considerable portion
of the heat produced by the fires is therefore taken up in raising the tempera-
ture of the atmospheric air to the degree necessary for its combination with
the sulphur, iron, and other metals.
The first part of our Patent consists in the use of air heated by suit-

page_text: able means before it comes over the ore under process, instead of cold air, in all
the processes above mentioned, where oxidation of the charge in the furnace
is desired.
The second part consists of treating copper ore in a peculiar construction of
furnace, by which the air may be heated without any extra consumption of fuel,
and which is attended with the advantage of preserving furnace by keeping it
cool.
We will now proceed to describe the furnaces usually adopted for the pro-
cesses before described. They will be better understood, and may be constructed
by any competent workman accustomed to the building of copper furnaces, by
reference to the accompanying Drawings.
The ore and metal calcining furnaces are of the description usually called
reverberatory. They are usually from fourteen to sixteen feet square in the
clear in the interior, having a fire-place at the back usually about three
feet in height by five feet in breadth, opening at the upper part into
the furnace over a wall of brick, which separates the fuel from the furnace,
and which is about two feet six inches high from the bottom of the furnace,
and about two feet wide, which is called the "bridge."
Figure 1 shews a sectional plan, and Figure 2 a sectional elevation, of a
calcining furnace, shewing the mode of admitting heated air into the calcining
furnace according to our Invention, which is by a number of flues, each about
five inches square, at the back of the fire-place, and separated from it by a
partition of fire brick about nine inches thick, having their external openings
at the bottom of the brickwork, leading upward to the top of the furnace, and
being carried forwards over the roof of the fire-place as far as the bridge, into
which it is let down through the sides of the furnace. A flue passes through
the bridge about nine inches high by four and a half wide, having two sets
of openings, one set at the top of the bridge about five inches from its front
surface, being each about four inches long by one inch wide, having under
them other openings sloping forwards and downwards to allow of the passage
into the calciner of ashes, or any solid matter coming over from the fire, and
which without such precaution would fill up the flue and render it useless,
the other set being situated in the inner surface of the bridge, about nine
inches from the bottom of the calciner, and being each about four inches
wide by three inches deep, for supplying heated air for the oxidation of the
ores or metals. The object of the first-mentioned set of flues which enter at
the top of the bridge is, to supply a sufficient quantity of heated atmospheric
air to complete the combustion of the gases evolved from the fuel as they pass
over the bridge into the furnace, on their way to the chimney or stack which

page_text: is placed on the opposite side or end of the furnace, whereby a higher tem-
perature is obtained with the ordinary consumption of fuel, and the injurious
influence of the carbonaceous gases on the calcining process is neutralized,
thus allowing the heated air introduced by the other set of holes immediately
above the ores or metals under process to have its full influence in effect-
ing their oxydation. The same object may be obtained by admitting the
air through two sets of flues having their external openings at the back
part of the bridge, (which goes perpendicularly to the ground, and forms the
back of the ash-pit,) in the ashpit, about three feet below the grate bars,
which openings are about five inches square, each one set of flues having
their internal openings at the top of a shield or arch of brick attached to the
top of the bridge in the inner side, and extending inwards over the bottom of
the furnace about fifteen inches. These openings into the furnaces are about
five inches by one inch, and are situated about five inches from the front of
the shield; each flue or external opening supplies air to two or more of these
internal openings. To prevent the filling up of these flues by ashes or solid
matter coming over from the fire-place, there is placed under each of them
an inverted funnel-shaped opening through the whole depth of the shield;
the other set of flues have their internal openings in the furnace, four inches
wide by three inches in depth, or thereabouts, and enter the furnace on the inner
surface of the bridge below the shield or arch, about nine inches above the
flat bottom of the calciner, and supply heated air for the oxidation of the
ores or metals. If the quantity of air admitted by the first-mentioned set of
flues is greater than is required for, or is not consumed in, the combustion
of the gases evolved from the fuel, of course the surplus passes into the fur-
nace, and acts upon the ores or metals in the same way as the air admitted
by the second-mentioned set of flues. Both sets of flues are conducted
through the brickwork of the bridge (being separated from the fire-place by
a partition of fire brick about seven inches thick) to the top of the bridge,
where they enter into two separate chambers, the one of which chambers
supplies heated air to the first-mentioned set of flues, which crosses the top
of the bridge and the shield or arch, for the combustion of the gases evolved
from the fuel, and the other supplying heated air to the second-mentioned set
of flues for the oxydation of the ores or metals in the furnace, the last-
mentioned set of flues simply crossing the top of the bridge, and thence
descending to within nine inches of the bottom of the furnace, where they
enter the furnace, both sets of chambers being at the same elevation, and
both being covered with fire bricks. The quantity of air admitted is regu-
lated by an iron or other plate suspended before the external openings in the
,

page_text: ash-pit, the supply of air being increased or diminished by the elevation or
depression of this plate. There are various other methods through which
heated air may be admitted to the furnaces through the sides of the furnaces,
as well as through the bridge. The object must be in all cases to expose as
large a surface of flues as possible to the action of the heat of the fire-place
or furnace. In applying heated air to the roaster furnace shewn at Figures
3, 4, 5, and 6, the apparatus for the admission of the heated air consists of
two or more sets of flues at the back of the fire-place, each flue or opening
being about five inches square, which are carried forward over the roof of
the fire-place, one set being introduced into the furnace over the bridge, and
infringing on the flame and carbonaceous gases, and the other set being con-
ducted down the side of the furnace into a flue about twenty-four inches
high near the bridge, and tapering to nine inches high at its termination near
the fore part of the furnace, and about six inches wide, running the whole
length of the side of the furnace opposite to where the stack or chimney may
be placed, and separated from the interior of the furnace by a partition of
fire brick about four inches and a half thick, and having six or more aper-
tures entering into the furnace along the side thereof, by which means a
number of currents of heated air are made to pass over the surface of the
metal contained in the furnace. The application of heated air has been
found of great benefit in the first and second, and in all the calcination fur-
naces, and in the roaster furnaces, and, in fact, everywhere were oxydation of
the charge is the object of the process. We have been particular in describ-
ing the exact means which we have found to answer best; but there are
various other parts of the furnace through which the air might be heated.
The dimensions of the flues and other parts which we have given, are those
which we employ, but the dimensions may be varied. A competent workman
will understand the management of a furnace, and he will regulate the
quantity of heated air admitted, and the time of admission, according to the
heat of the furnace, which, as heretofore, when admitting cold air, must
depend on the judgment of the workman. If the heat of the furnace is
sufficient to allow it, we believe that the more air he admits from the begin-
ning to the end of the process, the better and quicker will the operations be
performed. It will readily be understood, that the above furnaces, with the
use of heated air, are applicabe for the calcining of zinc ore or black jack,
and to all ores of whatever description which require to be subjected to the
process of roasting or calcining; and a workman acquainted with the necessary
treatment of black jack or other ores, will readily calcine the same in such
furnaces.

page_text: Another, the third part of our Invention, consists of a novel construction
of calcining furnace. The nature of the calcining furnaces at present gene-
rally adopted has been explained above. Our novel construction of calcining
furnace, shewn at Figures 7, 8, 9, 10, and 11, consists of a double furnace,
both being heated by the same fire. The fire-place opens into the upper
chamber or furnace; the flame, passing over the bridge as in the ordinary
calcining furnace before described, enters into and passes through the said
upper chamber or furnace, and conveying itself through four openings made
in the front part of the furnace, enters the lower chamber or furnace, and
passes backwards in the direction of the fire-place to two flues situated under
the bridge of the upper calciner, and which are connected with a stack or
chimney at the back of the fire-place; by this means the draught passes over
the surface of the charge contained in both chambers or furnaces. The bottom
of the lower calcining furnace is similar to that of calcining furnaces of the
ordinary construction. The flat bottom of the upper chamber or furnace rests
on two arches, supported in the centre by a wall about two feet in height,
running the whole length of the furnace from the bridge to the front, and
resting upon the lower bottom, and having in it a series of arched openings
to give the workman the command with the rabble of the whole of the bottom
from one side of the calciner. The bottom of the upper chamber or furnace
is pierced with thirty-six holes, to allow of the withdrawal of the surfaces
of the charge from time to time into the lower chamber when these
surfaces have been calcined to a sufficient extent in the upper chamber. The
charge thus withdrawn is allowed to remain in the lower chamber in the
shape in which it falls through the holes or openings, that is, in a sort of
cone under each opening; successive portions of the charge are withdrawn
from the upper chamber with the ordinary rabble in this manner until
the whole of the charge is deposited in the lower chamber, when a fresh
charge is placed in the upper chamber in the ordinary manner. The calcined
ore or metal is allowed to remain and accumulate in the lower chamber
until the quantity becomes inconvenient, when it is withdrawn as in the
ordinary calciner. The holes in the bottom of the upper chamber, through
which the charge is withdrawn into the lower chamber, are about six inches
square, and are closed by twelve dampers working into grooves formed in the
bottom, six being on each side of the furnace. These dampers are made of
two bars of wrought iron, placed six inches apart, and joined by welding at the
top and bottom, on which are rivetted three plates of iron one-fourth of an inch
thick and seven inches square, so fixed as to come immediately under the holes
when the damper is pushed into the groove. By withdrawing the damper

page_text: seven inches, the three holes are at once opened. The advantage of this cal-
cining furnace is, that by means of its two chambers it exposes a larger surface
of metal or ore to the action of the air and fire than can be obtained in the
ordinary calcining furnace, and for a longer period, thus ensuring a more perfect
and more rapid oxydation of the charge, and tending to create a greater or
of sulphate of copper, which is an advantage in the subsequent
process of melting. The heated air can be applied to it by the means already
described, merely making such changes in the position and direction of the
flues as the peculiar construction of the furnace renders necessary, and heated
may be applied with advantage to both chambers.
lesser
air
Another, the fourth part of our Invention, consists of a new mode of con-
structing the bottoms of copper melting and roasting furnaces, as shown at
Figures 3, 4, and 5. The mode of forming the bottoms of these furnaces
heretofore and at present adopted is to build a foundation arch of brick or
other suitable material running longitudinally underneath the furnace; a flat
platform of masonry is then made on this arch of the size of the interior of
the furnace, and on this platform is placed a layer of sand of about a foot in
thickness, which, after being properly calcined, is melted and set, after which
a second layer of sand about three inches in thickness is added, and is treated
in a similar way, when again a third layer of about five inches in thickness is
added and melted, making altogether a thickness of twenty inches of sand.
The sand employed is the common silicious sea sand, but should be free from
salt water. From want of a proper means of cooling the under part of this
mass of melted sand, and the consequent intense heat produced at a great
depth below the surface, these sand bottoms have always been found to abstract
and absorb a very large quantity of copper metal from the charges treated in
the furnaces, and considerable expence is incurred in breaking up these bottoms
when the furnace has become worn out, and a considerable amount of capital
is uselessly and unproductively occupied. To remedy this evil the plan we
have adopted is to excavate under the whole area of the furnace to the depth
of four to five feet; around the sides of this excavation a wall is raised about
five feet high, on which a number of plates of iron cast in the form of the
interior of the furnace, and about one inch in thickness, are placed across the
excavation, and are supported by pillars of brickwork, two being placed under
each plate. The joints between the plates are closed, either with clay or by
having thin strips of sheet iron placed over them, to prevent the sand which
is afterwards placed on the plates from running through. A layer of sand of
about fifteen inches in thickness is placed on the iron plate, and is calcined
and melted in the ordinary manner; to this layer another of about five inches

page_text: is added, and is similarly treated, when the bottom is complete, and the furnace
is ready for the first small charge of copper or metal, which is usually given to
season the bottom. To keep the iron plates constantly cool, a flue communi-
cating with the excavation under the furnace passes up the solid mass of
masonry in the front corner of the furnace opposite the stack through which
the rarefied air passes with great rapidity from beneath, by which means a
current of cold air is constantly brought in contact with the external surface
of the iron plates on which the bottom is supported. From the iron plates
being thus kept constantly at a moderate temperature, the sand bottom placed
on it absorbs only a very trifling quantity of the copper or copper metal com-
posing the charge in the furnace, as it (the copper or metal) is cooled and
solidified before it can reach the iron plates. The saving thereby occasioned
in interest of capital and expence of breaking up the bottoms of furnaces is
very great.
Having thus described the nature of our Invention, we would remark that
we do not confine ourselves to the precise details herein described, so long as
the peculiar character of either part of our Invention be retained; and we are
aware that reverberatory furnaces suitable for other manufactures than copper
have had heated air introduced at the bridges and other parts thereof; and
we mention this circumstance in order to state that we do not claim the intro-
duction of heated air into reverberatory furnaces generally, nor do we claim
the so-constructing reverberatory furnaces as to heat air before passing into
the same when uncombined with the process of oxydising copper ore or zinc
ore; and we are also aware that reverberatory furnaces have before been made
with cast iron bottoms when used in other processes than that of melting
copper and we are informed that a small experimental furnace for melting
copper was, before the date of our Patent, made and used with an iron
bottom, but without any provision for cooling the said iron bottom, which
would be inapplicable to large furnaces used for practical purposes; and we
mention these in order to say that we do not claim the use of iron bottoms to
furnaces unless combined with the melting of copper, and so arranged as to
allow of air or other fluid passing below to cool the same.
wish it to be understood that what we claim is,-
And we would
First, the application of air heated before it enters the furnace where copper
or zinc ore is being calcined, or copper or copper metal is being roasted, by
passing air near to or in contact with suitably arranged heated flues or ways.
Secondly, we claim calcining of copper or zinc ore and the roasting of copper
or copper metal in reverberatory furnaces, so arranged as to have air introduced
and heated by flues formed in the bridge, sides, or other parts of the furnace.

page_text: Thirdly, we claim the mode of constructing a calcining furnace whereby the
same is divided into two compartments, the upper one being heated directly by
the fire, and the lower one being heated by the heated products passing from
the upper to the lower compartment.
And, fourthly, we claim the mode of constructing the bottoms of copper
melting and roasting furnaces known as ore furnaces, metal furnaces, and
roasters, in such manner that the under surfaces may be kept cool by air or
other fluid.
In witness whereof, we, the said Edward Budd and William Morgan,
have hereunto set our hands and seals, the Twenty-sixth day of June,
in the year of our Lord One thousand eight hundred and forty-four.