An Improved Process of and Apparatus for Enriching and Separating Ores.
Year: 1888

page_text: Date of Application, 6th Oct., 1888
Complete Specification Left, 6th July, 1889-Accepted, 17th Aug., 1889
PROVISIONAL SPECIFICATION.
An Improved Process of and Apparatus for Enriching and
Separating Ores.
I, JOHAN GOTTFRIED LANDSTROM, of Granefors near Carlshamn, in the Kingdom of
Sweden, Engineer and Manager of Iron Works, do hereby declare the nature of this
invention to be as follows:-
My invention relates to a process of enriching and separating ores and to apparatus
therefor.
I have found by experiment that when sulphurets or arsenic sulphurets are calcined
or heated with access of air, the degree of temperature at which they yield their
sulphur and become oxidized differs considerably with different metallic compounds.
For instance copper pyrites become decomposed at a temperature under the boiling.
point of mercury, while common iron-pyrites require red heat and cobalt-nickel
glance and arsenic-nickel pyrites require white or incandescent heat for their
oxidation.
By reason of the property which certain oxides and sulphates of iron, nickel and
cobalt possess of being attached by the magnet, and by reason of the circumstance.
mentioned above, viz. :-t that a sulphuret or an arseniuret can be reduced to an
oxide when subjected to a suitable degree of beat it is possible to render them magnetic
and to base thereon a process of separating and enriching oros by magnetic separation,
when the ores consist of compounds of the said kinds.
It is well known that the magnetic metals are not attracted by the magnet under
all degrees of oxidation, and therefore it is necessary, when calcining or oxidizing
their sulphurets or arseniurets, to proceed so that only magnetic degrees of oxidation
are produced. This can be effected only under a suitable degree of heat and by
inclosing the ore from the fireplace itself and by finely dividing the ore, so that all
the molecules of the same may during a certain time he exposed to the action of the
air whilst being heated. If the flame should come in contact with the substances to
be calcined the calcination cannot be effected nor the required uniform heat be
maintained, consequently oxides of different degrees will be produced, some of which
are not magnetic, and it is then impossible to separate the ore.
My improved method of enriching and separating ferruginous, cobalt, or nickel
mixtures of sulphurets and arseniurets, consists in repeatedly heating. such mixtures
at the particular temperature adapted to each metallic compound.
Copper pyrites and cobalt-nickel pyrites I heat to a temperature not exceeding 350°
Celsius for from 10 to 15 minutes; common iron-pyrites to 600° Celsius for from 20
to 30 minutes, and grey cobalt (Speiskobolt) and cobalt-nickel glance to incandescense..
During the heating the separated and broken ore is inclosed in a muffle or other
suitable furnace to which air is admitted, but in such a manner that the flame does
not come into contact with the ore.
After each heating operation the mixture is treated by means of an ore-separator
with the view of first reducing the different ores successively in a magnetic state and
then separating the ore which was last rendered magnetic.
The said ore-separator advantageously comprises two obliquely superposed cylinders
having revolving brushes in connection with them.
These cylinders are at their circumferences provided with permanent or electro
magnets fixed in rows and surrounded with cement, the said rows being separated
by partitions of sheet iron or wood.
The magnets of the lower cylinder are stronger than those of the upper, so that

page_text: as the ore falls from a sieve upon the top cylinder, part of it will be retained thereby,
while the remainder falls down upon and is retained by the lower cylinder.
The ore is removed from the respective cylinders by the brushes.
Dated the 6th day of October 1888.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Process of and Apparatus for Enriching and
Separating Ores.
I, JOHAN GOTTFRIED LANDSTRÖM, of Granefors, near Carlshamm, in the Kingdom
of Sweden, Engineer and Manager of Ironworks, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
My invention relates to a process of onriching and separating ores and to apparatus
.therefor.
I have found by experiment that when sulphurets or arsenic sulphurets are calcined
or heated with access of air, the degree of temperature at which they yield their
sulphur and become oxidized differs considerably with different metallic compounds.
For instance, copper pyrites become decomposed at a temperature under the
boiling point of mercury, while common iron-pyrites require red heat and
cobalt-nickel glance and arsenic-nickel pyrites require white or incandescent heat for
their oxidation.
By reason of the property which certain oxides and sulphates of iron, nickel and
cobalt possess of being attracted by the magnet and by reason of the circumstance
mentioned above, viz. that a sulphuret or an arseniuret can be reduced to an oxide
when subjected to a suitable degree of heat it is possible to render them magnetic
and to base thereon a process of separating and enriching ores by magnetic separation
when the ores consist of compounds of the said kinds.
It is well known that the magnetic metals are not attracted by the magnet under
all degrees of oxidation and therefore it is necessary, when calcining or oxidizing
their sulphurets or arseniurets to proceed so that only magnetic degrees of oxidation
are produced. This can be effected only under a suitable degree of heat and by enclosing
the ore, from the fireplace itself and by finely dividing the ore so that all the
molecules of the same may during a certain time be exposed to the action of the air
whilst being heated. If the flame should come in contact with the substances to be
calcined the calcination cannot be effected nor the required uniform heat be maintained
consequently oxides of different degrees will be produced, some of which are not
magnetic and it is then impossible to separate the ore.
For the sake of example I will describe the process as applied for enriching and
separating a mineral or an ore consisting of a mixture of nickel or cobalt magnetic
pyrites, copper pyrites, iron pyrites, cobalt-nickel glance or any other mineral which
can only be transformed into a magnetic state, and rock when incandescent.
The ore broken to the fineness of sand is charged in an uncalcined state onto the
magnetic separator which extracts the nickel-cobalt iron pyrites. Air is then
admitted to the non-magnetic remainder which is heated in such a manner that the
flame does not come into contact with the ore powder. This heating takes place in
a inuffle furnace or, in order that the heating may be continuous, in a horizontal
revolving calcining cylinder, adapted for the purpose, at the inner side provided with
spiral grooves and fired. from below; the material is fed into one end and issues from
the other end perfectly calcined. The air has thus free passage through the cylinder.
The heating teinperature is such that only the copper pyrites is calcined (oxidized) by
which it becomes magnetic and may, when being cooled, be extracted by a suitable

page_text: magnetic ore separator. The separated non-magnetic remainder is again introduced
into the furnace and subjected to a stronger heat of such a degree that only the iron
pyrites is calcined (oxidized) and becomes magnetic when it can be extracted by the
magnets. The non-magnetic remainder is once more introduced into the furnace and
heated to incandescence when the cobalt-nickel glance becomes magnetic and may be
extracted. The residue, which consists of rock, may also contain some of the oxides
of the non-magnetic metals, as oxides of zinc, lead, silver, etc., which are enriched by
the extraction of the others.
The copper pyrites and cobalt nickel pyrites should be heated to a temperature not
exceeding 350° Celsius for from 10 to 15 minutes; the common iron pyrites to 600°
Celsius for from 20 to 30 minutes, and grey cobalt (Speiskobolt) and cobalt-nickel
glance to incandescence.
The process is particularly well adapted for enriching copper-pyrites, when these occur
together with common iron-pyrites, inasmuch as copper-pyrites oxidize, comparatively,.
more easily than the common iron-pyrites and become magnetic, when they can be
extracted by the magnets. Pure nickel-pyrites (Gunnarite) likewise becomes magnetic
about as easily as the copper-pyrites. Finally, it should be remarked that, by
imparting magnetism of varying strength to the magnets of both cylinders of the
separator hereinafter described, the degree of enrichment of a particular ore
may be varied.
For this purpose the strength of the magnets in the upper cylinder is such that they
are unable to raise or attract the ore grains containing more than a certain percentage
of rock, while the magnets of the lower cylinder, which are of greater power, can
raise or attract grains containing more rock. In this way a richer product is obtained
at the upper cylinder than at the lower.
In order to enable the invention to be fully understood I will proceed to describe
the same by reference to the accompanying drawing, in which
Figure 1 is a vertical section of the ore separator, and
Figure 2 is a front view of the same partly in section.
Figure 3 is a detail.
The various parts of the apparatus are arranged between two walls A; at the upper
part is the hopper B into which the finely broken ore is charged and by means of
an agitator C is fed down into the sieve D placed below the funnel. In the sieve D
which by means of suitable mechanism is agitated, the larger grains are separated but
smallar grains fall down between the guiding plates E fixed on the magnet cylinders F
and G which constitute the actual ore separators. The cylinders F and G consist of
drums on which are fixed parmanent or electro magnets H (Figure 3) arranged in
rows around the drums and surrounded by cement and are also connected to the
drums, by means of staples I. Between the magnets is a partition K of wood or
sheet iron.
The magnets of the upper cylinder F are not so powerful as the magnets in the
lower cylinder G by which means (whether it is desired to separate grains of ore of
different richness, or different ores, with magnetism of varying strength) the richer
ore the more magnetic ore is retained by the magnets of the upper cylinder and
carried along to the brush L revolving in the opposite direction to the cylinder and
is brushed down into the shoot Q. The stronger magnets of the lower cylinder G
are capable of attracting grains containing more rock, that is to say, the ore grains
of feebler magnetism pass round with the cylinder to the brush M and are brushed
down into the shoot N. The rock, which may contain non-magnetic ores such as
lead-glance, sulphide of zinc or the like, passes into the receptacle Ö.
The drawing illustrates the manner in which motion is transferred to the different
parts of the machine by means of cords or belts running over pulleys fixed on the
shafts of the magnet-cylinder and the brushes outside the apparatus. The motion of
the cylinders should however be regulated by means of toothed wheels, fixed on the
cylinder shafts or in any other suitable manner in which a regular motion of the
cylinders can be effected. The cylinders are so adjusted with respect to each other
that, during their motion, magnetic poles of different denominations always meet each

page_text: other at the point where the cylinders run next to each other. In this way for every
magnet passing the other in the different cylinders an attraction is set up which
constantly excites the magnetism and contributes to the maintenance of the magnetism
in an unimpaired state..
The brushes are arranged. in movable bearings. After finishing work and before:
the machine is allowed to stop, the brushes are removed and the magnets are allowed:
to collect as much as possible of the ore grains thus constituting an armature which
also contributes to the inaintenance of the magnetism of the magnets.
It is obvious, that the dimensions of the machine, particularly the width of the
cylinders, may be increased according to the capacity desired and that by using an
additional cylinder with still stronger magnets the separation may be still further
continued or improved.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. The method of enriching and separating ferruginous, cobalt or nickel mixtures
of sulphurets and arseniurets consisting in repeatedly heating such mixtures at the:
particular temperature adapted to each metallic compound, for example copper pyrites.
and cobalt-nickel pyrites are heated to a temperature not exceeding 350° Celsius for
from 10 to 15 minutes; common iron pyrites to 600° Celsius for from 20 to 30
minutes; and grey cobalt (Speiskobolt) and cobalt-nickel glance to incandescence;
the separated and broken ore being enclosed in a muffle or other suitable furnace
during the heating, air being admitted to the furnace in such a manner that the
flame does not come into contact with the ore and after such heating operation the
mixture being treated by means of an ore separator with the view of first reducing
the different ores successively in a magnetic state and then separating the ore which.
was last rendered magnetic, substantially as herein before described.
2. The manufacture and use of an ore separator consisting of two obliquely
superposed cylinders F, G having revolving brushes L and M, the peripheries of the
cylinders being provided with permanent or electro magnets fixed in rows and
surrounded with cement, the said rows being separated by partitions of sheet iron or
wood; the magnets of the lower cylinder are stronger than those of the upper cylinder
so that as the ore falls from a sieve upon the top cylinder part of it will be retained
while the remainder falls down upon and is retained by the lower cylinder, the ore
being removed from the cylinders by the respective brushes, substantially as, and for
the purpose, hereinbefore described and illustrated in the accompanying drawing.
Dated the 6th day of July 1889
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.