IMPROVEMENTS IN THE TREATMENT OF CUPREOUS PYRITES
Year: 1878

page_text: LETTERS PATENT to Henry Hills, of the Paragon, Blackheath, in the County
of Kent, and Charles Henry Hills, of West House, Tynemouth, in the County
of Northumberland, Gentlemen, for the Invention of "IMPROVEMENTS IN
THE TREATMENT OF CUPREOUS PYRITES."
Sealed the 17th May 1878, and dated the 14th March 1878.
PROVISIONAL, SPECIFICATION left by the said Henry Hills and Charles
Henry Hills at the Office, of the Commissioners of Patents on the 14th March
1878.
HENRY HILLS, of the Paragon, Blackheath, in the County of Kent, and CHARLES
HENRY HILLS, of West House, Tynemouth, in the County of Northumberland,
Gentlemen. ".IMPROVEMENTS IN THE TREATMENT OF CUPREOUS PYRITES."
Our Invention relates to the treatment after calcination of a certain class of
cupreous pyrites, rich in iron and sulphur, and containing but little silica, and is
especially applicable to the ores imported into Great Britain from Spain and Portugal,
or ores of a similar composition.
The ordinary process for the treatment of these ores is to crush them to coarse
powder, mixed with salt, roast them in close or other furnaces, lixiviate the mass
with hot water and weak acid, and then precipitate the copper from the solution
with iron. This process is attended by the disadvantage that the ore has to be so
finely crushed, in order to extract the copper, as to render the said ore unfit to be
subsequently smelted into iron in blast furnaces, and consequently the general
practice is to use the said ores simply for fettling iron furnaces.
Now the objects of our Invention are to render a considerable portion of the
oxide of iron residue obtained in the treatment of the aforesaid pyrites available
for reduction to metallic iron in blast furnaces, to make the remainder into the
ordinary fettling ore, known as "purple ore," and also to extract from the said ores
the copper contained therein, together with the silver and gold (if any). .
,

page_text: For these purposes we proceed as as follows:-The cupreous pyrites after having
been calcined and deprived of the greater part of its sulphur in the manufacture of
sulphuric acid or for other purposes, may first be screened to separate the portion of
the ore which is small enough for the purposes of the process herein-after described,
and the larger pieces may be passed through suitable crushing machines and screens
(or the ore may be passed direct through the crushing machines without previous
screening), the mesh of the screens or the size of the apertures therein being from a
quarter to half an inch, according to the character of the ore to be treated, and the
care that has been taken in its calcination.
The ore so crushed is by preference passed over a screen of fine mesh or perforation 1
to separate the smallest particles or dust which may be treated in calcining or
chloridizing furnaces, either alone or in admixture with coarser portions of the
ore after the lixiviation (herein-after described) of the latter for treatment as herein-
after described.
The remainder of the ore is by preference carried forward into suitable filter vats
and lixiviated with weak muriatic or sulphuric acid and water, used hot by prefer-
ence, or with hot water alone, and the liquors so obtained are run into vats
containing iron for the precipitation in the usual manner of the copper held in
solution.
The ore thus deprived of the soluble salts of copper and iron is to be classified
and dressed by "jigging" or other suitable water-dressing machinery for the pur-
pose of separating by gravity the bulk of the kernel copper formed in calcination
and the unburnt sulphides of copper and iron from the rest of the ore, which may
be either smelted into regulus copper or recalcined as at first, and this applies more
especially to the larger sized portion of the ore crushed and screened out as before
described.
It is not essential for the working of the Invention that any of the crushed ore,
which is sufficiently small to chloridize in the ordinary way, should be passed
through the water-dressing process, but only the coarser sizes which are available
for smelting to iron, but in all cases it facilitates the extraction of copper.
The first lixiviation, hercin-before described, may also be dispensed with, and the
crushed ore be dressed, after passing the crushing machines and classifying sieves ;
the liquors used for the dressing process being drawn off from time to time into
copper precipitating vats and replaced by fresh water.
The lightest part of the ore (principally oxides, which form the greatest portion
of the ore) which passes away from the dressing machine is then to be conveyed to
suitable furnaces, and either roasted to oxidize the sulphides and sub-salts which
remain or mixed with salt and chloridized. Or if the copper is found refractory and
difficult to roast or chloridize quickly enough, a little iron salt or raw pyrites may
be added to facilitate the treatment. The ore is then passed again into the filter
vats and lixiviated with hot water and a sufficient quantity of weak acids to dis-
solvo out the copper.
If the ore is oxidized in the furnaces and it contains silver and gold, or either, the
said ore may after the copper is washed out be mixed with a small quantity of salt
or brine, and be again passed rapidly through furnaces to chloridize the precious
metal or metals, which can then be lixiviated out and be precipitated by iron,
together with the small quantity of copper that is left in the ore from the first
lixiviations, or be precipitated by other suitable precipitants and the precipitate
obtained therefrom may be treated for the precious metals by any suitable method.
Or if this ore has been chloridized, the precious metals can be recovered by Claudet's
iodide process or by any other available process.
After passing the classifying screens and dressing machinery, the different sizes
of ore so classified may be kept and treated separately or together, or the smaller
sizes may be treated with larger quantities of salt by the present method of treat-
ment, known as "Henderson's process." But the larger sizes of the crushed ore
which it is one of the chief objects of this process to obtain (and which cannot be
obtained by the chloridizing process as it is at present conducted for this class of

page_text: calcined cupreous pyrites, owing to the small size of crush, which is found necessary
for the complete extraction of the copper) are available as iron ore for reduction to
iron in blast furnaces, while the remainder, consisting of small lumps and powder,
can be used as fettling ore or for other purposes. The proportion of the larger sizes
obtained by this process will vary from 20 to 50 per cent. of the whole, according
to the nature of the ore and the size of the screens used, and will be of much higher
value than the ordinary "purple ore," as at present prepared, which is crushed too
small to be utilized in blast furnaces.
The kernal copper and unburnt portions of the ore separated by the dressing
process will be rich in copper, and contain from about 5 to 15 per cent. of this metal,
varying according to the per-centages contained in the raw mineral. This portion
of the ore may be divided into two or more qualities.
The richest in copper may be smelted for that metal direct, as herein-before stated,
and the part containing the least copper may be recalcined in suitable furnaces for
the manufacture of sulphuric acid, or be roughly calcined in open furnaces, and then
passed again through the original process.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Hills and Charles Henry Hills in the Great Seal Patent Office
on the 14th September 1878.
HENRY HILLS, of the Paragon, Blackheath, in the County of Kent, and CHARLES
HENRY HILLS, of West House, Tynemouth, in the County of Northumberland,
Gentlemen: "IMPROVEMENTS IN THE TREATMENT OF CUPREOUS PYRITES."
Our Invention relates to the treatment after calcination of a certain class of
cupreous pyrites, rich in iron and sulphur, and containing but little silica, and is
especially applicable to the ores imported into Great Britain from Spain and Portugal,
or ores of a similar composition.
The ordinary process for the treatment of these ores is to crush them to coarse
powder, mix with salt, roast them in close or other furnaces, lixiviate the mass with
hot water and weak acid, and then precipitate the silver by Claudet's iodide process,
and the copper from the solution with iron. This process is attended by the dis-
advantage that the ore has to be so finely crushed, in order to extract the copper,
as to render the said ore mechanically unsuitable for smelting into iron in blast
furnaces, and consequently the general practice is to use the said ores simply for
fettling iron furnaces.
Now the objects of our Invention are to render a considerable portion of the
oxide of iron residue obtained in the treatment of the aforesaid pyrites suitable for
reduction to metallic iron in blast furnaces, to make the remainder into the ordinary
fettling ore known as "purple ore," and also to extract from the said ores the copper
contained therein together with the silver and gold (if any).
For these purposes we proceed as follows:-The cupreous pyrites after having
been calcined and deprived of the greater part of its sulphur in the manufacture of

page_text: sulphuric acid or for other purposes may first be screened to separate the portion of
the ore which is small enough for the purpose of the process, herein-after described,
and the larger pieces may be passed through suitable crushing machines and
screens (or the ore may be passed direct through the crushing machines without
previous screening), the mesh of the screens or the size of the apertures therein
being from a quarter to three-quarters of an inch, according to the character of the
ore to be treated, and the care that has been taken in its calcination.
The ore so crushed is by preference passed over a screen of fine mesh or perfo-
ration to separate the smallest particles or dust, such mesh being of the sizes usually
employed for preparing cupreous ores for the chloridizing process, and the ore which
passes through such mesh may be treated in calcining or chloridizing furnaces,
either alone or in admixture with coarser portions of the ore after the lixiviation
(herein after described) of the latter for treatment as herein-after described.
The smaller or dust portion of the ore screened out, as described above, will
contain lower per-centages of copper and sulphur than the original bulk of the
calcined cupreous pyrites contained. The chloridizing of this portion of the ore
is consequently easier.
The remainder of the ore is by preference carried forward into suitable filter vats
and lixiviated with weak muriatic or sulphuric acid and water, used hot by prefer-
ence, or with hot water alone, and the liquors so obtained are run into vats
containing iron for the precipitation in the usual manner of the copper held in
solution.
The ore thus deprived of the soluble salts of copper and iron is to be classified
and dressed by jigging or other suitable water-dressing machinery for the purpose
of separating by gravity the bulk of the kernel copper forined in calcination and
the unburnt sulphides of copper and iron from the rest of the ore, which may be
either smelted into regulus copper or recalcined as at first; and this applies
more especially to the larger sized portion of the ore crushed and screened out, as
before described.
It is not essential for the working of the Invention that any of the crushed ore,
which is sufficiently small to chloridize in the ordinary way, should be passed
through the water-dressing process, but only the coarser sizes which are available
for smelting to iron, but in all cases it facilitates the extraction of copper.
The first lixiviation, herein-before described, may also be dispensed with, and the
crushed ore be dressed after passing the crushing machines and classifying sieves,
the liquors used for the dressing process being drawn off from time to time into
copper precipitating vats and replaced by fresh water.
The lightest part of the ore (principally oxides, which form the greatest portion of
the ore) which passes away from the dressing machine, is then to be conveyed to
suitable furnaces, and either roasted to oxidize the sulphides and sub-salts which
remain, or mixed with salt and chloridized. The ore is then passed again into the
filter vats and lixiviated with hot water and a sufficient quantity of weak acids to
dissolve out the remaining copper.
If the ore is oxidized in the furnaces, and it contains silver and gold, or either,
the said ore may, after the copper is washed out, be mixed with a small quantity of
salt or brine, and be again passed rapidly through furnaces to chloridize the precious
metal or metals which can then be lixiviated out, and be precipitated by iron,
together with the small quantity of copper that is left in the ore from the first
lixiviations, or be precipitated by other suitable precipitants, and the precipitate
obtained therefrom may be treated for the precious metals by any suitable method.
Or if this ore has been chloridized, the precious metals can be recovered by Claudet's
iodide process, or by any other available process.
After passing the classifying screens and dressing machinery, the different sizes
of ore so classified may be kept and treated separately or together; but the larger
sizes of the crushed ore, which it is one of the chief objects of this process to obtain
(and which cannot be obtained by the chloridizing process, as it is at present con-
ducted for this class of calcined cupreous pyrites, owing to the small size of crush

page_text: which is found necessary for the complete extraction of the copper) are available as
iron ore for reduction to iron in blast furnaces, while the remainder, consisting of
small lumps and powder, can be used as fettling ore, or for other purposes. The
proportion of the larger sizes obtained by this process will vary from 20 to 50 per
cent. of the whole, according to the nature of the ore and the size of the screens
used, and will be of much higher value than the ordinary "purple ore" as at
present prepared, which is crushed too small to be economically utilized in blast
furnaces.
.
The kernel copper and unburnt portions of the ore separated by the dressing
process will be rich in copper, and contain from about 5 to 20 per cent. of this metal,
varying according to the per-centages contained in the raw mineral. This portion
of the ore may be divided into two or more qualities.
The richest in copper may be smelted for that metal direct, as herein-before stated,
and the part containing the least copper may be recalcined in suitable furnaces for
the manufacture of sulphuric acid, or be roughly calcined in open furnaces, and then
passed again through the original process.
Having thus described the nature of our Invention, and the manner in which
the same is to be performed, we claim in respect thereof,-
Firstly. The application of the jigging or water-dressing process, essentially as
herein-before described, to the separation of unburnt sulphides and kernal copper
from calcined cupreous pyrites, and thus rendering a large proportion of the
oxide of iron residue of such pyrites available for direct smelting in ordinary
blast furnaces.
Secondly. The chloridizing and lixiviating of the ore after the jigging and oxidation
thereof, as herein-before described, in order to obtain the silver and gold, or either,
with the copper remaining in the said ore after the first lixiviation.
In witness whereof, I, the said Charles Henry Hills, have hereunto set
my hand and seal, this Twelfth day of September, in the year of our Lord
One thousand eight hundred and seventy-eight.
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