IMPROVEMENTS FOR SEPARATING COPPER. AND OTHER METALS FROM THEIR ORES
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I HENRY
DAVY, of Ottery Saint Mary, in the County of Devon, Gentleman, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Second day of Septem-
ber, One thousand eight hundred and forty-seven, in the eleventh year of Her.
reign, did, for Herself, Her heirs and successors, give and grant unto me, the.
said Henry Davy, my exors, admors, and assigns, Her especial licence, full power,
sole privilege and authority, that I, the said Henry Davy, my exors, admors,
and assigns, or such others as I, the said Henry Davy, my 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, my, Invention of "IMPROVEMENTS FOR SEPARATING COPPER.
AND OTHER METALS FROM THEIR ORES;" in which said Letters Patent is contained
a proviso, that I, the said Henry Davy, should cause a particular description
of the nature of my said Invention, and in what manner the same is to be
performed, by an instrument in writing under my hand and seal, to be inrolled
in Her 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, I, the said
Henry Davy, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are particularly described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked thereon,
that is to say:-
The first part of this Invention refers to the apparatus for heating air, and for
the more convenient, effectual, and economical production of what is called the
hot blast, to be employed in blast furnaces for the smelting of iron, copper, and
other metals.
According to my Invention, it will in some cases be sufficient simply to
introduce into pipes, similar to those at present, or hereafter employed, for heat-
ing air, pieces or fragments of fire brick or of iron, or of other suitable substance,
in such quantities as may be found not too much to obstruct the current of air;
and I prefer for the cooler parts to introduce pieces of copper, blackened or
reddened by superficial oxidation or otherwise, and for the hotter parts pieces
of fire-brick dipped in a solution of nitrate of copper, by which when heated
A
they will acquire a blackened surface, favorable for the radiation of heat.
similar result may be obtained by causing the air, for the sake of extended
surface, to pass through a number of smaller pipes instead of through a single
larger one, such small pipes, as the case may require, being united into a single
main pipe either near the entrance or exit from the flue, or both. But the
arrangement which I believe will combine the greatest advantages will be
understood by reference to the annexed Figure 1, which represents a tranverse
section of the hot-air pipe with its interior appendages, and of the smoke flue
in which it is enclosed. a is the brickwork in which the flue is enclosed; b,
the lining of the flue, shaped as represented in the Figure, but with the
concavities and convexities as great as convenience will admit of for extension
of surface; this lining may be made of plates of cast iron in the cooler, and of
tiles of fire clay in the (fire brick material) in the hotter parts of the flue. c is
a stratum of pounded charcoal or coke or dry sand between the lining of the
fluo and the brick work to confine the heat; d is the hot-air pipe, with eleva-
tions and depressions for extension of surface, corresponding with the concavities,
and convexities in the lining of the flue in such a manner as that the opposing
surfaces of the one and the other may be nearly equidistant at all points; e, e,
are a number of pieces of sheet or plate iron or other material, single or double,
uniting on a central axis f, and extending into the concavities of the air pipe d
so as to present opposing surfaces to receive the radiated heat from the inner
surface of the air pipe and communicate it to the air.

page_text: It will be found advantageous in those portions of the apparatus which are
most remote from the fire by which the flue is heated) to make use of piping
much thinner than that which can be safely adopted in those parts which will be
exposed to a higher temperature; the tubes thus arranged may be arched or
bent in any suitable figure, as have been heretofore practised. This method of
heating air may be employed either in connection with a blowing machine or
without, as in cases where the current of air through the air pipe may take
place spontaneously in consequence of heat applied.
And whereas it may be in some cases desirable to raise the air to an
extremely high temperature, such as would, perhaps, preclude the employment
of cast iron for the pipes or for the twyere, I propose in such cases to substitute
pipes and twyeres of fire clay or crucible ware, lined internally with thin sheet
platina, to prevent leakage from cracks which may occur in such pipes, and
bound externally with hoops or spiral turns of platina wire, or of bar iron cased
with platina foil, to hold the pieces together, whenever such cracks in the
piping may occur; and in order to prevent injury to the platina from the
sulphur contained in the coal when the fuel is employed, it may be desirable to
pass the air already heated as much as possible in the iron pipes through pipes
such as I have just described, placed in a second or separate flue or fire-place
in which wood charcoal only is burned; and the sheet platina for lining the
pipes may be platinized, according to Mr. Smee's method of galvanism, to
increase its radiating power.
And, further, it will be advantangeous in those portions of the apparatus
which are most remote from the fire by which the flue is heated to make use of
piping much thinner than that which can be safely adopted in those parts
which will be exposed to a higher temperature, this method of heating may
be employed either in connection with a blowing machine or without.
The second part of my Invention refers to the roasting or calcination of cer-
tain ores of copper or copper pyrites, and such ores of metals generally as contain
sulphur, by means of hot air, which should be raised to a temperature of seven
hundred degrees of Fahrenheit, or upwards, passed over or through them in a
suitable apparatus, and to the saving of the sulphurous and sulphuric acid thus
produced by treatment with nitric or nitrous acid vapour, as in the ordinary
inanufacture of oil of vitriol or sulphuric acid. The acid liquor thus obtained
may be manufactured into suitable sulphuric acid by concentration in the usual
way, or it may be added to the roasted ore of copper to dissolve the
oxide of copper contained therein, by which means a solution of sulphate of
copper is obtained, from which the copper may be precipitated in the metallic
state by the immersion therein of iron plates.

page_text: The third part of my Invention refers to an improvement in the construction
of the blast furnace to be used in the smelting of cer.ain or.s, particularly
those of copper ores known as oxides and carbonates. When charcoal or coke
is used in the blast furnace it is well known that the carbon thereof becomes
converted in the act of combustion into carbonic acid gas, but this in passing
afterwards through the heated fuel which lies above it will combine with a
quantity of carbon equal or nearly equal to that which it already contains, and
thus become converted into inflammable carbonic oxide gas, which without it
meets with fresh air will not burn until it reaches the exit of the furnace where
its combustion will produce a certain degree of heat, the effect of which is lost,
and a considerable portion of the fuel is consequently consumed wastefully. If
common coal be used instead of charcoal or coke, then there will probably be
in addition to the carbonic oxide a quantity of carburetted hydrogen burnt to
waste at the exit of the furnace.
In order to render intelligible the nature of my improvement I must
refer to Figure 2, which represents a sketch of the furnace that I employ
in the smelting of ores of copper, known as the oxides and carbonates of
copper. a is one of the twyers through which the hot blast is conducted
at a proper distance above the hearth or bottom of the furnace; b, b, is
the mixture of ore and fuel contained in the body of the furnace; is a
prolongation of the furnace upwards, separated from the body of the furnace
by a grating d, which consists of moveable bars capable of being pulled out when
required; e, e, are apertures for the admission of fresh air, partly below, but
principally just above the grating, capable of regulating the quantity of air
admitted; f, a flue for insuring the proper indraught of air through these
apertures; g, an opening for introducing the charge of ore or fuel, with a cover
capable of being closely fitted. Supposing this furnace to be in action, then
the proper quantity of ore mixed with whatever flux it may require for a
single periodical charge of the furnace is introduced at the aperture 9 into c
where it will rest upon the grating d, and gradually become heated to a certain
temperature by the combustion of the gas or gases before mentioned, in con-
sequence of the admission of fresh air into this part of the furnace. When the
proper time arrives for the admission of a fresh charge into this part of the
furnace, then tle bars of the grating d are to be slided out, and the hot ore
will pass into the body of the furnace, and a corresponding proportion of fuel is
immediately to be introduced through the same aperture g, so that it may also
fall at once into the body of the furnace, where it will lie upon the hot ore;
after this the bars of the grating at d are to be slided back and a new charge
of cold ore introduced into c to acquire its preparatory heat, as before.

page_text: According to this arrangement, it is evident that we have the power of so
regulating the admission of air that it may at option be either in excess or
deficient for the perfect combustion of the inflammable gases. A furnace
constructed on the same principle may be used for the smelting of other
description of copper ores besides the oxidés and carbonates of that metal, but
those ores in which these largely predominate may be successfully smelted into
copper of moderately good quality by one operation in the blast furnace.
The fourth part of this Invention refers 'particularly to the smelting in the
blast furnace of those ores of copper known as the oxides and carbonates, or of
ores in which the oxides and carbonates largely predominate. These, when
they contain no other advantitious metallic oxides but those of iron or man-
ganese, may be successfully smelted into metallic copper of moderately good
quality by one operation in the blast furnace.. I.commence. by ascertaining by
a rough analysis of a fair sample the proportion which the silica, if any, in the
ore bears to the iron or manganese, or both, which it may contain, and if the
silica be about in the proportion of as five to the metallic iron, and manganese
(existing in the oxides thereof) as seven, then the ore may be smelted without
the addition of any flux, provided it contain .no considerable quantity of .other
earthy substances; but if the proportions differ from those above stated, then, as
the case may be, either quartz, sand, or else the oxide. either. of iron..or of
manganese must be added, so as to obtain about the before-mentioned pro,
portions in the mixture; and practically this object will generally be obtained
wholly or in part by due mixture of ores already containing-more or.less either
of silica or of the oxides of iron or manganese; and in practice the proportions
may, after sufficient experience, often be judged of by the eye without resorting
in every case to analysis. The richer and poorer ores ought also to be so mixed
that the average does not contain more, however much less, than from twenty
to twenty-five per cent. of copper, in order that there may be a due proportion
of slag to cover and protect from re-oxidation the surface of the reduced copper.
The ore or mixture is then to be exposed to beat in the herein-before de-
scribed blast furnace blown with hot air, and fed with charcoal, coke, or coal,
or mixtures thereof, as fuel; the melted copper will then settle at the bottom
of the furnace, from which it may be tapped, and cast in the usual manner,
while the other fused ingredients of the ore, and the mixtures that may have
been made therewith, and the ashes of the fuel, will together melt for the most
part into a fusible slag which will run out of the furnace separate from the metal.
I wish it to be understood that I make no claim to the employment of hot
air generally for melting purposes; but I claim the improvement in the method
of heating air, which consists essentially in increasing the heating surface

page_text: without proportionately augmenting the general dimensions of the apparatus,
according to the arrangement herein described.
I make no claim to the obtaining of sulphuric acid by the combustion of
iron pyrites, but I claim the roasting of copper and other ores containing
sulphur by means of hot air and the conversion of the products of the sulphur
into sulphuric acid.
Thirdly, I claim the so arranging or constructing blast furnaces so as to
introduce air towards the upper part for the purpose of inflaming the products,
as above described.
And, fourthly, I claim the mode of smelting copper ores by a due admixture
in blast furnaces, as above described.
In witness whereof, I, the said Henry Davy, have hereunto set my hand
and seal, this Twenty-eighth day of February, in the year of our Lord
One thousand eight hundred and forty-eight