IMPROVEMENTS IN THE TREAT.. MENT OF COPPER ORES FOR OBTAINING COPPER AND OTHER PRODUCTS THERE- FROM
Year: 1878

page_text: LETTERS PATENT to Thomas Henry Cobley, of Kingsbury House, Dunstable,
in the County of Bedford, for the Invention of "IMPROVEMENTS IN THE TREAT..
MENT OF COPPER ORES FOR OBTAINING COPPER AND OTHER PRODUCTS THERE-
FROM."
PROVISIONAL SPECIFICATION left by the said Thomas Henry Cobley at the
Office of the Commissioners of Patents on the 22nd November 1878.
THOMAS HENRY COBLEY, of Kingsbury House, Dunstable, in the County of Bedford.
"IMPROVEMENTS IN THE TREATMENT OF COPPER ORES FOR OBTAINING COPPER AND
OTHER PRODUCTS THEREFROM."
My Invention relates to the treatment of copper ores so as to obtain therefrom
solutions suitable for electrolytic deposition of copper and other products, some of
which may be employed in the said treatment. When the ore contains chiefly
sulphides, as in the case of copper pyrites, I roast it, pulverised if necessary, first at
a moderately low temperature, driving off by sublimation a portion of the sulphur
(which may be used for the production of sulphur or sulphuric acid or otherwise),
and afterwards at a higher temperature with free access of air. The roasted ore is
then lixiviated with steam, water, or liquor from the depositing tanks with the
addition, when necessary, of sulphuric acid. The solutions thus obtained may be
strengthened by passing them repeatedly through masses of the roasted ore.
and other impurities are removed from the solutions by the addition of powdered
limestone or chalk, or by passing the solutions through beds of these materials.
Otherwise the strong solutions containing salts of copper, iron, alumina, and other
substances are allowed to cool and crystallise, whereupon the crystallised salts can
be removed and the mother liquor can be used for attacking fresh quantities of
orc. Or the solutions may be evaporated to a pasty condition by passing through
them the hot sulphurous fumes proceeding from the roasting, the fumes being thus
cooled ready for their subsequent treatment. The crystals or pasty masses obtained
1
Iron

page_text: as above described contain matters which obstruct electrolytic action. To remove.
these I calcine at a temperature comparatively below red leat, so as not to decom-
pose the sulphate of copper, but to reduce the iron compounds to subsulphate, oxide,
and other insoluble conditions. The mass thus calcined being again dissolved
furnishes a solution of sulphate of copper suitable for electrical deposition. The
hydrated oxide of copper may be precipitated from the solutions by caustic lime, or
the carbonate of copper by magnesite, dolomite, or carbonate of lime applied at
boiling heat. Sulphate of copper is obtained from these products by the action of
sulphuric acid, which may be that produced from the sulphurous fumes of the
roasting, or that contained in the liquors of the depositing vats. In the latter
case in order to economise time and labour the oxides and carbonates of copper may
be fed into the vats in which the electrical deposition of copper is effected. Through
these vats I also pass the sulphurous acid fumes resulting from the roasting of the
ore, so as to absorb oxygen and thus prevent polarisation, and for this purpose other
gases, such as carbonic oxide or products of combustion of fuel, may be employed.
From the liquors containing sulphate of copper more or less freed from iron and
other impurities, as above described, I precipitate metallic copper by means of a
current of electricity, which may be obtained from any known source, but con-
veniently from the working of a dynamo-electric machine. I convert the sulphurous
fumes and gases into sulphuric acid and sulphur by condensing them in acidulated
water or the solution of an alkaline sulphate, such as sulphate of soda, and then
subjecting the liquor to electrical action until the acid is present in large quantity.
The liquor is then left to settle till the sulphur subsides, when it is separated by
decantation. The decanted acid can then be concentrated or it may be at once
applied in dissolving the ore.
The process described with suitable modifications is applicable to ores containing
carbonates and oxides of copper. The carbonate ores are roasted to facilitate the
mechanical separation of the gangue and the concentration of the copper oxide, which
may be effected by any known means. The oxide with the addition of pitch, tar,
or resin may be pressed into briquettes and reduced to metallic copper in the usual
way. Or the oxide may be dissolved in sulphuric acid or the liquors of the
depositing vats to form sulphate of copper for electrical deposition. By feeding the
vats with the oxide the solution under deposition may be maintained in a con-
dition of normal strength. Carbonates of copper contained in the ores may be
converted into sulphates by roasting them with an admixture of sulphide ore or
with the crude sulphur resulting from the electrical treatment of the sulphurous
fumes and gases.
The roasted product is then lixiviated and treated as above
described with reference to the sulphates of copper otherwise obtained.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Henry Cobley in the Great Seal Patent Office on the 21st
May 1879.
THOMAS HENRY COBLEY, of Kingsbury House, Dunstable, in the County of Bedford.
"IMPROVEMENTS IN THE TREATMENT OF COPPER ORES FOR OBTAINING COPPER AND
OTHER PRODUCTS THEREFROM."
My Invention relates to the treatment of copper ores so as to obtain therefrom
solutions suitable for electrolytic deposition of copper and other products, some of
which may be employed in the said treatment. When the ore contains chiefly
sulphides as in the case of cupreous pyrites, it is to be carefully roasted or calcinor
so as to eliminate the extraneous sulphur and convert the sulphide into a soluble
sulphate. This conversion may be effected by any known means, but it is preferred
to effect it by exposing the crushed pyrites in a closed furnace provided with a
chamber for collecting the sulphur fumes to a temperature at which the one atom of
sulphur is driven off leaving the mass in the form of protosulphide.
The proto-
sulphide thus obtained is drawn upon the hearth of an oxidiser and roasted down
till sulphate is formed. In order to complete sulphatisation at the close of the
roasting a little powdered pyrites or sulphur may be thrown in. The mass is then
removed to lixiviating tanks where it is lixiviated by steam or steam and water or
liquor from the depositing tanks hereinafter mentioned. Before lixiviation the
roasted mass may be tempered with a little dilute sulphuric acid or persulphate in
order to take up oxide formed during the roasting. The solutions may be.
strengthened by passing them repeatedly through fresh masses of the roasted ore.
Iron and other impurities are removed from the solutions when cold by the ad-
dition of powdered limestone or chalk, magnesite, or dolomite, or by passing the
solutions through beds of these materials. Or the solutions containing salts of
copper, iron, alumina, and other substances are concentrated to a crystalising
strengh, then allowed to cool and crystalise, whereupon the crystalised salts can be
removed and the mother liquors can be used for attacking fresh quantities of ore.
Or the solutions may be evaporated to a pasty condition by passing over or through
them the hot sulphurous fumes proceeding from the roasting, the fumes being thus,
cooled ready for their subsequent treatment or application. The crystals or pasty
masses obtained as above described contain matters which obstruct electrolytic
action. To remove these I calcine at a temperature below read heat, so as not to
decompose the sulphate of copper, but to reduce the iron compounds to subsulphate,
oxide, and other insoluble conditions. The mass thus calcined being again dissolved
furnishes a solution of sulphate of copper suitable for electrical deposition.
effecting the electrical deposition of copper from the solutions thus obtained in order
to economise time and labour I feed the solution with oxide or carbonate of copper,
so as to keep up the strength of the depositing liquor. To prevent polarisation
during deposition I introduce into the depositing vats fumes of sulphurous acid from
the roasting ore so as to absorb oxygen, and for this purpose other gases, such as
carbonic oxide or products of combustion of fuel, may be employed. For the pre-
cipitation of metallic copper I employ currents of electricity, which may be obtained
from any known source, but conveniently from the working of a dynamo-electric
machine. I convert the sulphurous fumes into sulphuric acid and sulphur by con-
densing them in acidulated water or a solution of an alkaline sulphate, such as
sulphate of soda or sulphate of alumina, through which a current of electricity is
conducted until the acid is present in considerable quantity. The mixture being
then left to settle till the sulphur subsides the acid liquor is decanted and may be
concentrated in the usual way, or it may be at once applied in dissolving ore.
In
The process described with suitable modifications is applicable to ores containing
carbonates of copper. In order to facilitate the mechanical separation of the gangue
and to concentrate the copper I find it advantageous to drive off the carbonic acid

page_text: by a gentle roasting. The roasted ore is then placed in a receptacle in which loose
stone blocks are carried round by revolving arms as in apparatus for grinding flint
or for treating silver ores. While the mass is being triturated water is allowed to
flow over it, so as to facilitate the operation and to float over the fine particles,
which are collected in settling vats. The enriched slimes thus obtained may be
farther dressed and smelted in the usual way, or they may be dissolved in sulphuric
acid or liquors from the depositing vats to form sulphate of copper, from which
metallic copper is electrically deposited, as above described. By feeding the de-
positing vats with the oxide the strength of the depositing solution may be main-
tained. The carbonate or concentrated oxide may likewise be converted into
sulphate by roasting them with the crude sulphur resulting from the electrical
treatment of the sulphurous fumes or the condensed fumes of the roasting or with
an admixture of powdered pyrites. The roasted product is then lixiviated and
treated as above described with reference to the sulphates of copper otherwise
obtained.
Having thus described the nature of my Invention and in what manner the same
is to be performed, I claim in the treatment of copper ores for obtaining copper and
other products therefrom,-
First. Converting cupreous pyrites by calcination into protosulphide, substantially
as and for the purpose herein set forth.
Second. Preparing solutions containing sulphate of copper suitable for depositing
copper by electricity, as herein described.
Third. Checking polarization during the electric deposition by introducing into
the depositing solution sulphurous acid fumes, carbonic oxide, or gaseous products of
combustion, substantially as herein described.
Fourth. Maintaining the strength of the depositing solution by feeding it with
oxide or carbonate of copper, substantially as herein described.
Fifth. Concentrating carbonate of copper ore and facilitating separation of the
gangue by roasting and trituration in water, substantially as herein described.
Sixth. Converting copper carbonate or concentrated oxide into sulphate suitable
for electrical deposition by roasting with sulphur or sulphide and lixiviation, sub-
stantially as herein described.
Seventh. Treating the sulphurous acid fumes by the electric current for the pro-
duction of sulphuric acid and sulphur, as herein described.
In witness whereof, 1, the said Thomas Henry Cobley, have hereunto set my
hand and seal, this Sixteenth day of May, in the year of our Lord One
thousand eight hundred and seventy nine.
TUTO
TIENDY CORTY
THOMAS HENRY COBLEY. (L.S.)