AN IMPROVED METHOD OF SMELTING COPPER ORE
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
SCHAFHAUTL, of Cornhill, in the City of London, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Sixth day of March, in the second year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Charles Schafhautl, Her especial licence that I, the said Charles Schafhaut,
my exors, adiñiors, and assigns, or such others as I, the said Charles Schaf-
haut, my exors, admors, or assigns, should at any time agree with, and n
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, my Invention of
"AN IMPROVED METHOD OF SMELTING COPPER ORE;" in which said Letters Patent
there is contained a proviso, obliging me,. the said Charles Schafhautl, by an
instrument in writing under my hand and seal, particularly to describe and
ascertain the nature of my said. Invention, and in what manner the same
is to be performed, and to cause the same to be enrolled in Her Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said. recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear. .
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Schafhaut!, do hereby declare the nature of my said Invention, and
the manner in which the same is to be performed, is described and ascer-
tained in the. Drawings hereunto annexed, and the following explanation
thereof, that is to say:
:
My Invention consists partly in the preparation of the commonly used

page_text: copper ores, which are in their essential parts bisulphates of copper and
iron, or poly-sulphurets, where sulphurets of copper and iron are mixed
with the sulphurets of other metals, or simple carbonates, of copper by
reducing them to a pulverized state, the finer the better, and mixing
them intimately with any alkaline or earthy base which has a great affinity
for the sulphur contained in the copper ore. As the least costly, I
prefer quicklime, such as is ordinarily used for mortar in building. And
in order to produce as perfect a mixture as I can, I put the necessary
quantity of quicklime on the top of the pulverized copper ore in an in-
closure or wooden tank or vessel to prevent the water running off, and
slaking the lime with water on the top of the ore, stirring and mixing the
lime as it slakes with the copper ore, and adding as much water as will put
the whole mass in a state of thin mortar. To hasten the process of smelting
I afterwards mix with this mass a portion of common kitchen salt or chloride
of sodium, the addition of which is not, however, absolutely necessary, but it
prevents the development of smoke and hastens the process of smelting. The
proportions which I consider best and recommend, without binding myself
to such proportions for the mixture of ores which contain from five to twelve
per cent. of copper ore, are, for five parts by weight of copper ore two parts
and a half of fresh burnt quicklime and one part of salt, where the latter is
used. This mixture may be then calcined in a common calciner, such as is at
present used for that purpose, at a red heat, until the whole is converted into a
dry powder and the coarser pieces of calcined ore on trial shew no undecom-
posed pyrites. When the ore is only a carbonate of copper no calcining is
necessary, but it may be immediately smelted with the mixture. The process
of calcining in a common calciner is always a very tedious part of the process
of smelting, and difficult to be perfectly accomplished. I therefore use a calciner
invented by myself, the construction of which calciner forms the second part of
my Invention, and which I shall herein-after describe. When the calcination
of the copper ore is finished, the mass is to be drawn red hot, and imme-
diately put into water, which runs in the central air chamber of my newly
invented calciner below the hearth of the furnace. After the calcination of
each charge of ore which the calciner contains is finished, the previously cal-
cined ore is thrown out of the air chamber during the recharging of the
calciner, and washed in the washing hearth of the calciner, which washing
hearth is marked p in the Drawings annexed, Nos. 4, 5, and 6, and to which
I refer as part of this description, and the ore must be frequently stirred,
while water is flowing in at one end of the washing hearth and running out
over the top at the other end, which must be above the level of the copper ore

page_text: contained therein. This operation should be continued until the water runs
off tolerably clear. The water thus running out contains a good deal of sul-
phuret and sulphate of lime as well as oxyde of iron and other metals; and.
although this washing.is not absolutely necessary to the smelting of copper, it
considerably quickens the operation, as the water carries off a great deal of
the sulphuret, sulphate, and oxydes before mentioned. The more perfectly
and completely the ore is subjected to the before-mentioned operation, the more
advanced will it be when smelted down in a common smelting furnace or
roaster as now in use, as the copper obtained will be in a state of white metal,
black blistered copper ore, or in an intermediate state in proportion to the care
taken in observing the foregoing directions. The metal obtained by smelting
down the calcined ore may be kept in the same furnace with a plentiful
admission of air, if not sufficiently advanced to, be put into the refining fur-
nace, care being taken to draw off the scoria or slack from the furnace,
as often as it appears, and to throw from time to time, with a shovel, sea
sand, containing a considerable quantity of marine shells, or in the absence of
sea sand, a mixture of quicklime and anthracite or stone coal.
In all cases
where the scoria or slack becomes thick, foul, and mixed with the metallic
copper, sand must be plentifully added until the scoria or slack becomes
sufficiently silicated to let the copper sink freely to the bottom; and should
the scoria or slack contain oxyde of copper, then anthracite and quicklime
in about equal proportions must be used to reduce the oxide to the metallic
state. If it is intended at the same time to produce sulphuric acid, the
copper ore must be mixed with carbonaceous matter. That which I have
found to answer best is about half the weight of the copper of plumbago or of
anthracite or stone coal, and calcine it in my newly invented calciner herein-
before referred to; or when the copper ore is very poor, it may be smelted
down and converted into what is called coarse metal in the way now com-
monly in use; and the metal be run into water over a round cast-iron plate,
so that it may be divided more minutely; this so divided metal I mix with
carbonaceous matter. I prefer either plumbago, black lead, or anthracite
free from sulphur, for the sake of their greater durability, in about the pro-
portion of one quarter the weight of the metal, and calcined in a common or in
my said newly invented calciner, till all traces of sulphur or arsenic are driven
off. This calcined matter is then smelted down in a roaster, and when
the scoria or slack, which is generally the case, becomes thick and foul, it is to
be treated with sand as herein-before mentioned, and, if it contains oxyde of
copper with anthracite, till the metal is fit for the refining furnace.
The second part of my Invention-consists in the construction of a calcining

page_text: furnace or oven, which has for its object, first, the creating a more perfect
and rapid contact of the air with the ore spread over the hearth of the calciner.
Secondly, to prevent the escape of: any sulphureous of arsenious fumes, or to
convert such sulphureous fumes, if desired, into sulphuric acid, and to effect
these objects the fire grate of the furnace is shut off from immediate commu-
nication with the air by means of the valve K.and the 'doors L, L, in the
annexed Drawing No. 3, and which are made so close as to be air-tight, or as
nearly so as may be, and to be covered with wet clay in the ordinary manner;
the closed fire-place communicates with the central air chamber f, Drawing
Nos. 1, 2, and 4, below the hearth of the calciner, and by way of the channel
b', Drawing Nos. 1, 2, 3, 5, and 6, with the hearth or chamber b, where the
ore is placed for calcining, which hearth or chamber is open to the access of
air on one side only, as shewn in Drawing No. 1, where the arrows shew the
entrance and current of air, in consequence of which the air which feeds the
fire (all other communication being cut off) enters here and rushes in one con-
tinued stream over the ore, as shewn by the direction of the arrows, oxidising
the sulphur and arsenic and carrying with it all the fumes through the air
chamber f, Drawing No. 1, and passing with the air and steam which arises
from the water "n," which fills the bottom of the ash-pit and air chamber
through the ignited fuel of the fireplace; the fumes of the sulphur are con-
verted into sulphuric acid, and stream with the flames backwards into the
flame chamber d, Drawing Nos. 2, 4, 5, and 6, and from thence over the
vaulted calcining chamber, through the passage a into the chimney i, i, Draw-
ing No. 1, where they may be easily condensed by the means of steam. The
ore after it is calcined is thrown through the channels g,g, Drawing No. 1, 2,
5, and 6, down into the air chamber, and thus exposed to the action of the
water n, which is to be allowed to flow in slowly by the botom of the ash-pit
shutting it up air-tiglit, thence proceeding into the air chamber f, and from
thence flowing out into the said place p, called the washing hearth, from which
it escapes by an opening to be made a little lower than the level of the water,
carrying with it the sulphates and sulphurets of lime and other matters,
as before mentioned. When it is intended to make sulphuric acid, the
channels g, g, must be constructed in the usual manner, so as to let the cal-
cined ore run into a pit, as is now commonly practised, and not into the air
chamberf. The cast-iron valve k is to shut off the entrance of air to the bars
of the grate, and the doors L, L, below the valve shut up the ash pit air-tight
and serve to clean out the ashes when requisite; and opposite these doors at
the other end of the furnace the air chamber is enclosed with similar doors,
which allow the workmen to withdraw the ore from the air chamber to the

page_text: washing hearth. d, d, are two channels which conduct the flames back by the
way a, a, over, the upper vault of the calcining chamber into the chimney i, i;
the bottom of both channels may contain water to create steam and to con.
dense partially the sulphuric acid. The calcining chamber b, Drawing Nos. 1,
2, and 3, consists of two parallel arches extending through the whole width of
the furnace. The lower arch, which forms the hearth on which the ore is
spread, may be constructed of slabs of fire clay, from two to two inches and
a half thick, twenty-four inches long, and twelve inches wide, the surface of
which is shewn in Drawing No. 6, b, which slabs rest on fire bricks r, r, placed
vertically, Drawing No. 2 and 5, which form passages c, c, for the flames from
the fireplace, as shewn in Drawing Nos. 2 and 5. Two funnels in the usual
manner (only one of which is shewn in the Drawing h, h, Nos. 1 and 2) convey
the ore to the calcining chamber b, but in passing through the air passage a,
care must be taken that the passage is kept air-tight, so that the returning
current of flames is not interrupted.
And in giving the description and in referring to the annexed Drawings in
explanation of the same, I claim as part of my Invention,-
Firstly, the mixing the ore with bodies of an alkaline nature which have an
affinity for sulphur in order to decompose the sulphurets, or of mixing the same
alkaline bodies and carbonaceous matter to decompose the carbonate of
copper, or the mixing the ore or metal to be calcined, roasted, or smelted with
carbonaceous matter, particularly plumbago or anthracite, and the said mix-
ture of alkaline bodies and carbonaceous matter when the scoria or slack
contains oxide of copper, and a mixture of carbonaceous matter and sea sand
when the scoria or slack contains oxide of copper and metallic copper; quick-
lime and carbonaceous matter are usual in the common process of smelting
copper, but quicklime is then only used for the first smelting in very limited
quantities as a flux, and is never applied in the calcining process, and not in
large quantities in calcining, and is never mixed with carbonaceous matter;
and carbonaceous matter is also sometimes used for reducing the scoria or
slack of the fourth smelting, which scoria or slack is the result of smelting the
calcined coarse metal; carbonaceous matters are also used in refining the
copper as a cover for toughening the same, and never in calcining, roasting, or
smelting the ore as I apply it, and to which I restrict my Invention, and do
not extend the same to the use of alkaline or carbonaceous matters as now
used.
Secondly, I claim as part of my Invention the causing the air which has
passed over the heated ore in the calcining chamber mixed with the rising
fumes and steam to pass through the fire grate of the same furnace connected

page_text: with the calciner, as shewn in the. annexed Drawings, by its own action or
through a separate furnace, before it escapes through the chimney.
In witness whereof, I, the said Charles Schafhautl, have hereunto set
my hand and seal, this Fifth day of September, in the year of our Lord
One thousand eight hundred and thirty-nine.
AND BE IT REMEMBERED, that on the Fifth day of September, in
the year of our Lord 1839, the aforesaid Charles Schafhautl came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Inrolled the Fifth day of September, in the year of our Lord One
thousand eight hundred and thirty-nine.