United States Patent [19]
Kindig et at
[11]
[45]
4,276,081
* Jun. 30, 1981
[21] Appl. No.: 101,583
[22] Filed: Dec. 10, 1979
Shubert 209/214
Kindig et al. 44/1 R
McEwan et al 423/417
Kindig et al. 44/1 R
Kindig et al. 44/1 R
Kindig et al. 44/1 R
Westcott : 209/8
Kindig et al. ,..................... 209/214
ABSTRACT
12/1975
2/1976
1111977
7/1978
10/1978
10/1978
2/1980
6/1980
3,926,789
3,938,966
4,056,386
4,098,584
4,119,410
4,120,665
4,187,170
4,205,979
[57]
76 Claims, No Drawings
FOREIGN PATENT DOCUMENTS
28375 7/1931 Australia 75/6
179095 7/1954 Austria 75/112
4527990 11/1980 Canada 75/6
119156 8/1959 U.S.S.R 209/212
OTHER PUBLICATIONS
Henderson, J. G., et al., Metallurgical Dictionary, Rheinhold
Publishing Corp., N. Y., p. 227 (1953).
Sinclair, J. S., Coal Preparation and Power Supply at
Collieres, London, pp. 15-17, (1962).
Primary Examiner-Michael L. Lewis
Attorney, Agent, or Firm-Sheridan, Ross, Fields &
McIntosh
In a process for beneficiating one or more mineral values
of sulfide ores and/or metal oxide ores selected
from the group consisting of bauxite, taconite, apatite,
titanium oxides and the metal oxides of Groups IlIB,
IVB, VB, VIB, VlIB, VIIIB, IB, lIB and IVA by treating
the ore with a metal containing compound under
conditions such as to selectively enhance the magnetic
susceptibility of the mineral values to the exclusion of
the gangue in order to permit a separation between the
values and gangue, the improvement comprising removing
at least a portion of any elemental sulfur present
from the ore prior to the treatment with a metal containing
compound.
References Cited
Related U.S. Application Data
Continuation-in-part of Ser. No. 950,177, Oct. 10, 1978,
abandoned.
Assignee:
Notice:
Int. CI.3 C22B 1/02
U.S. CI 75/7; 75/6;
75121
Field of Search 75/1 R, 1 T, 6-9,
75/21, 28, 7277, 82, 87, 111, 122; 423/23, 138,
25; 209/8, 9, 212-214; 427/47, 252,253,255,
129, 132
U.S. PATENT DOCUMENTS
933,717 9/1909 Lockwood et al. 209/214
1,053,486 2/1913 Ethenington 75/1 R
2,132,404 10/1938 Dean 423/25
2,332,309 10/1943 Drummond 427/252
2,612,440 9/1952 Altmann 75/0.5
2,944,883 7/1960 Queneau et al 75/0.5
3,220,875 11/1965 Queneau et al 427/47
3,252,791 5/1966 Frysinger et al 75/119
3,323,903 6/1967 O'Neill et al 75/0.5
3,466,167 9/1969 Illis et al. 75/112
3,490,899 1/1970 Krivisky et al 423/25
3,669,644 6/1972 Sato 423/25
3,671,197 6/1972 Mascio 75/6
3,758,293 9/1973 Viviani et al 75/6
[73]
[* ]
[63]
[54] PROCESS FOR BENEFICIATING ORES
[75] Inventors: James K. Kindig, Arvada; Ronald L.
Turner, Golden, both of Colo.
Hazen Research, Inc., Golden, Colo.
The portion of the term of this patent
subsequent to Jun. 3, 1997, has been
disclaimed.
[51]
[52]
[58]
[56]
BEST MODE FOR CARRYING OUT THE
INVENTION
2
means, including, for example, heat pretreatment, steam
pretreatment, solvent extraction and chemical reaction.
The process of the present invention is particularly
useful for concentrating sulfide or metal oxide minerals
from ore mixtures containing sufficient elemental sulfur
such that the sulfur interferes with the interaction of the
10 metal containing compound and the mineral values.
The process entails the p.retreatment to remove elemental
sulfur from the ore, thereafter treating the ore with
a metal containing compound in order to selectively
enhance the magnetic susceptibility of various mineral
15 values contained within the ore. The treated mixture
can then be treated by magnetic means to produce a
beneficiated product.
The connection of elemental sulfur in sulfide ores
varies greatly, and may range from less than one part
per million to greater than 8,000 parts per million. Although
many metal oxide ores do not contain elemental
sulfur in their naturally occurring state, a number of
such ores do exist in the presence of varying amounts of
elemental sulfur. This wide range is dependent upon the
type of ore and the particular mineral deposit. Concentrations
of elemental sulfur as small as one part per
million, at least in some ores, are sufficient to hinder the
selective magnetic susceptibility enhancement reaction.
Higher concentrations of elemental sulfur generally
create a greater hindrance. Therefore, essentially any
removal of elemental sulfur prior to performing the
magnetic susceptibility enhancement treatment improves
the recovery of mineral values. Preferably the
concentration of elemental sulfur following treatment
for its removal will be less than about 100 parts per
million, more preferably less than about 50 parts per
million and most preferably less than about 10 parts per
million, based on the total weight of the ore being
treated.
Essentially any process for removing elemental sulfur
from: the ore can be utilized as the pretreatment means.
Examples of suitable processes include heat treatment,
steam treatment and solvent extraction.
The heat pretreatment essentially comprises heating
the ore in order to remove the elemental sulfur. It is
generally preferred that the pretreatment comprise
heating the ore to a temperature of from about 800 C., to
about 5000 C., more preferably to a temperature of from
about 1500 C. to about 3500 C., and most preferably to
a temperature of from about 1750 C. to about 2500 C.
This heat pretreatment is preferably maintained for at
least about 0.1 hour and more preferably for at least
about 0.5 hours. Generally higher temperatures necessitate
shorter periods of time in order to accomplish the
pretreatment.
The heat pretreatment step may be conducted in the
presence of one or more gaseous additives, and this is
preferably under many circumstances. Examples of
suitable gaseous additives inclUde nitrogen, steam, carbon
monoxide, carbon dioxide, ammonia, methane, air,
ethane, propane, butane and other hydrocarbon compounds
which exist in the gaseous state at the pretreatment
temperature. Some of these additives, under certain
conditions, serve as chemical reactants in removing
elemental sulfur. '
When these additives are employed, it is preferable
that they be employed in an amount of at least about 2,
4,276,081
1
DISCLOSURE OF THE INVENTION
PROCESS FOR BENEFICIATING ORES
CROSS-RELATED PATENT APPLICATIONS
This application is a continuation-in-part application 5
of U.S. Ser. No. 950,177 filed Oct. to, 1978 now abandoned.
TECHNICAL FIELD
This invention relates to an improved means for treating
sulfide or metal oxide ores to separate the mineral
values from gangue material by selectively enhancing
the magnetic susceptibility of the mineral values so that
they may be magnetically removed from the gangue.
BACKGROUND ART
As is well.known, mining operations in the past for
recovering various metals (e.g., lead and copper) have
utilized high grade ore deposits where possible. Many
of these deposits have been exhausted and mining of 20
lower grade ores is increasing. The processing of these
leaner ores consumes large amounts of time, labor, reagents,
power and water with conventional processing.
In addition to the increased expense associated with
the extraction of these metals from low grade ores, 25
proposed processes for separation of certain of the suI·
fide ores are technically very difficult and involve elab·
orate and expensive equipment. In many cases the expense
incurred by such separation would be greater
than the commercial value of the metal, such that the 30
mineral recovery, while theoretically possible, is economically
unfeasible.
Our copending patent applications Ser. No. 086,830
ftled Oct. 22, 1979 entitled "Process for Beneficiating
Sulfide Ores" and Ser. No. 921,583 filed July 3, 1978 35
entitled "Process for Beneficiating Oxide Ores" teach
the treatment of these ores with a metal containing
compound under conditions such as to selectively enhance
the magnetic susceptibility of the mineral values
to the exclusion ofthe gangue, allowing for a separation 40
ofthese values from the gangue. However, the presence
of a particular impurity can have a profound effect on
this type of process. More particularly, it has been
found that the presence of elemental sulfur has an adverse
effect on the recovery of mineral values in a pro- 45
cess which enhances the magnetic susceptibility of the
mineral values. Pretreating the raw ore to remove at
least a portion of the elemental sulfur present, and thereafter
selectively enhancing the magnetic susceptibility
of the mineral values so that they may be physically 50
separated from the gangue, substantially enhances the
effectiveness of the separation of the mineral values
from the gangue.
55
The process of the present invention entails beneficiating
sulfide ores or metal oxide ores selected from the
group consisting of bauxite, taconite, apatite, titanium
oxides and the metal oxides of groups IIIB, IVB, VB,
VIB, VIIB, VIIIB, IB, lIB and IVA containing elemen- 60
tal sulfur by pretreating the ore to remove at least a
portion of the elemental sulfur, and thereafter treating
the ore with a metal containing compound under conditions
such as to selectively enhance the magnetic susceptibility
of the mineral values to the exlcusion of the 65
gangue, thereby permitting the removal ofthese values
from the gangue. The pretreatment for removing the
elemental sulfur may be performed by any suitable
\
4,276,081
3
more preferably at least about 12 and most preferably at
least about 120 cubic meters per hour per metric ton of
ore being processed.
A particularly preferred additive is steam. Heat pretreatment
with steam is preferably conducted within a 5
temperature range of from about 100· C. to about 500·
C. and more preferably from about ISO· C. to about
350· C. and most preferably from about 1750 C. to about
250· C. Preferably the pretreatment should be conducted
for at least about 0.1 hours, more preferably for 10
at least about 0.25 hours and most preferably for at least
about 0.5 hours. The amount of water preferably ranges
from about 1 weight percent to about 50 weight percent,
more preferably from about 5 weight percent to
about 30 weight percent and most preferably from 15
about 10 weight percent to about 25 weight percent,
based on the weight of the ore being treated.
Alternatively, the ore can be pretreated with a solvent
or a combination of solvents to effect elemental
sulfur removal. Examples of suitable solvents include 20
petroleum ether, carbon tetrachloride, toluene, acetone,
ethyl alcohol, methyl alcohol, ether, carbon disulfide,
liquid ammonia and other compounds suitable to dissolve
elemental sulfur. Preferred solvents include carbon
tetrachloride, petroleum ether, toluene and ace- 25
tone.
The amount of a particular solvent used will be dependent
on lhe degree of solubility the elemental sulfur
exhibits in the solvent at the treatment temperature.
Generally, it is preferable that the solvent be employed 30
in an amount of at least about one half, more preferably
at least about 3 and most preferably at least about 10
liters per kilogram of ore.
After the initial pretreatment step to remove the elemental
sulfur, the ore is treated to selectively enhance 35
the magnetic susceptibility of the mineral values.
"Enhancing the magnetic susceptibility" of the ore as
used herein is intended to be defined in accordance with
the following discussion. Every compound of any type
has a specifically defined magnetic susceptibility, which 40
refers to the overall attraction of the compound to a
magnetic force. An alteration of the surface magnetic
characteristics will alter the magnetic susceptibility.
The metal treatment of the inventive process alters the
surface characteristics of the ore particles in order to 45
enhance the magnetic susceptibility of the particles. It is
to be understood that the magnetic susceptibility of the
original particle is not actually changed, but the particle
itself is changed at least at its surface, resulting in a
particle possessing a greater magnetic susceptibility 50
than the original particle. For convenience of discussion,
this alteration is termed herein as "enhancing the
magnetic susceptibility" of the particle or ore itself.
The sulfide minerals which are capable ofundergoing
a selective magnetic enhancement in accordance with 55
the process include the metal sulfides of Groups VIB,
VIIB, VIIIB, IB, lIB, IlIA, IVA and VA. These sulfides
preferably specifically include the sulfides of molybdenum,
tungsten, manganese, rhenium, iron, ruthenium,
osmium, cobalt, rhodium, iridium, nickel, palla- 60
dium, platinumm, copper, gold, silver, zinc, cadmium,
mercury, tin, lead, arsenic, antimony and bismuth.
The metal oxide minerals which are capable of undergoing
a selective magnetic enhancement in accordance
with the process include the metal oxides of Groups 65
I1IB, IVB, VB, VIB, VIIB, VIIIB, IB, lIB and IVA,
the titanium oxides of Group IVB, aluminum hydrate,
i.e., bauxite, of Group lIlA, taconite, chrysocolla and
4
apatite. It is recognized that taconite and chrysocolla
are classified as silicates and apatite is classified as a
phosphate, and it is further recognized that apatite does
not contain elements generally classified as metals
(other than calcium). However, for the purposes of this
inventive process they are classified as metal oxides.
The preferred oxide minerals include bauxite, apatite,
cuprite, cassiterite, carnotite, scheelite, chrysocolla and
hematite.
The gangue minerals from which the metal sulfides
and metal oxides can be separated include those minerals
which do not undergo a sufficient magnetic susceptibility
enhancement as· a result of the process. These
gangue minerals include, for example, silica, alumina,
gypsum, muscovite, dolomite, calcite, albite and feldspars,
as well as various other minerals. The term
gangue as used herein refers to inorganic minerals with
which sulfide and oxide ores are normally associated.
The term does not include coal.
In those ores which contain naturally relatively
strongly magnetic constituents, such as magnetite, the
magnetic material may first be removed by passing the
mixture through a magnetic separator. The nonmagnetic
portion obtained by this precleaning step is then
subjected to the pretreatment for sulfur removal and
treatment with a metal containing compound to enhance
the magnetic susceptibility.
Prior to the sulfur removal pretreatment or treatment
with the metal containing compound, the ore must be
ground to liberate the metal sulfide or metal oxide particles
from the gangue particles, if the respective components
do not already exist in this liberated state. The ore
may be crushed finer than necessary to achieve liberation,
but this is not generally economically feasible. It is
generally satisfactory to crush the ore to at least about
minus 14 mesh, although many ores require grinding to
minus 65 mesh or fmer.
Numerous metal containing compounds are capable
of enhancing the magnetic susceptibility of the metal
sulfides and metal oxides in accordance with the invention.
Many iron containing compounds possess the capability
of enhancing the magnetic susceptibility of the
mineral values of the ore, as long as the compound is
adaptable so as to bring the iron in the compound into
contact with the mineral value under conditions such as
to cause an alteration of at least a portion of the surface
of the mineral value.
Iron containing compounds capable of exerting sufficient
vapor pressure, with iron as a component in the
vapor, so as to bring the iron into contact with the value
at the reacton temperature are suitable, as well as other
organic and inorganic iron containing compounds
which can be dissolved and/or "dusted" and brought
into contact with the mineral value contained within the
ore. Preferred compounds within the vapor pressure
group are those which exert a vapor pressure, with iron
as a component in the vapor, of at least about 10 millimeters
of mercury, more preferably of at least about 25
millimeters of mercury and most preferably of at least
about 50 millimeters of mercury at the reaction temperature.
Examples of groupings which fall within this
vapor pressure definition include ferrocene and its derivatives
and beta-diketone compounds of iron. Specific
examples include ferrocene and iron acetylacetonate.
Other organic compounds which may be utilized to
enhance the magnetic . susceptibility include those
which may be homogeneously mixed with a carrier
liquid and brought into contact with the components of
4,276,081
5
the ore. Such mixtures include, for example, solutions,
suspensions and emulsions. These mixtures must be such
as to provide sufficient metal to contact the surface of
the mineral value. Suitable carrier liquids include, for
example, acetone, petroleum ether, naphtha, hexane, 5
benzene and water; but this, of course, is dependent
upon the particular metal compound being employed.
Specific groupings include, for example, ferrocene and
its derivatives and the carboxylic acid salts of iron, such
as, iron octoate, iron naphthenate, iron stearate and 10
ferric acetylacetonate.
Additionally, solid organic iron containing compounds
capable of being directly mixed with the ore in
solid form possess the capability of enhancing the magnetic
susceptibility of the metal sulfides and metal ox- 15
ides. The compound must be in solid form at the mixing
temperature and be of sufficiently fine particles size in
order to be able to be well dispersed throughout the ore.
The particle size is preferably smaller than about 20
mesh, more preferably smaller than about 100 mesh and 20
most preferably smaller than about 400 mesh. Compounds
within this grouping include ferrocene and its
derivatives, iron salts of organic acids, and beta-diketone
compounds of iron. Specific examples include
ferrous formate, l,l'-diacetyl ferrocene, and 1,l'-dihy- 25
droxymethyl ferrocene.
Various inorganic compounds are also capable of
producing an enhanced magnetic susceptibility. Preferred
inorganic compounds include ferrous chloride,
ferric chloride and the metal carbonyls, including, for 30
example, iron, nickel, cobalt, molybdenum, tungsten
and chromium carbonyls and derivatives of these compounds.
Iron carbonyl is a preferred carbonyl for imparting
this magnetic susceptibility, particularly iron
pentacarbonyl, iron dodecacarbonyl and iron nonacar- 35
bonyl. The more preferred metal containing compounds
capable of enhancing the magnetic susceptibility
are iron pentacarbonyl, ferrocene and ferric acetylacetonate,
with iron pentacarbonyl being the most prefurred.
~
The process is applied by contacting the iron containing
compound with the ore at a temperature wherein
the iron containing compound selectively decomposes
or otherwise reacts at the surface of the metal sulfide or
metal oxide particles to alter their surface characteris- 45
tics, while remaining essentially unreactive, or much
less reactive, at the surface of the gangue particles. The
temperature of the reaction is a critical parameter, and
dependent primarily upon the particular compound and
the particular ore. The preferred temperature can be 50
determined by heating a sample of tbe specific iron
containing compound and the specific ore together until
the decomposition reaction occurs. Suitable results generally
occur over a given temperature range for each
system. Generally, temperatures above the range cause 55
non-selective decomposition while temperatures below
the range are insufficient for the reaction to occur.
While as indicated above, techniques other than
vapor injection methods may be employed as applicable
depending upon the metal containing compound being 60
utilized, the following discussion primarily applies to
vapor injection techniques, specifically iron pentacarbonyl,
as these are generally preferred. Similar considerations,
as can be appreciated, apply to the other described
techniques. 65
The preferred temperatures when iron pentacarbonyl
is employed as the treating gas are primarily dependent
upon the ore being treated. It is generally preferred to
6
select a temperature which is within a range of 125° C.,
more preferably 50° C. and most preferably 15° C. less
than the general decomposition temperature of the iron
carbonyl in the specific system. The general decomposition
temperature is intended to mean the temperature at
which the iron carbonyl decomposes into iron and carbon
monoxide in indiscriminate fashion, causing a magnetic
enhancement of the gangue as well as the metal
sulfide or metal oxide. The "specific system" is intended
to include all components and parameters, other than,
of course, temperature, of the precise treatment, as the
general decomposition temperature varies with different
components and/or different parameters. This decomposition
temperature range can be readily determined
by analytical methods and often a trial and error
approach is preferred to determine the precise temperature
range for each specific system.
The amount of the metal containing compound used
and the time of treatment can be varied to maximize the
selective enhancement treatment. With respect to iron
carbonyl the preferred amount employed is from about
0.1 to about 100 kilograms per metric ton of feed, more
preferably from about 1 to about SO kilograms per metric
ton of feed, and most preferably from about 2 to 20
kilograms per metric ton of feed. The treatment reaction
is generally conducted for a period of time of from
about 0.05 to about 4 hours, more preferably from about
0.15 to about 2 hours and most preferably from about
0.25 to about 1 hour.
After the feed mixture containing the metal sulfide or
metal oxide values has been treated with a metal containing
compound, it can then be subjected to a magnetic
separation process to effect the separation of the
sulfides or mineral value of the metal oxides. Any of
many commercially available magnetic separators can
be used to remove these values from the gangue. For
example, low or medium intensity separations can be
made with a permanent magnetic drum separator, electromagnetic
drum separators, induced roll separators,
or other configurations known to those skilled in the
art. Since most sulfides are liberated at a mesh size of 65
mesh or finer, a wet magnetic separatic::. process is
more effective. Thus, high intensity, high gradient wet
magnetic separators are preferred for the sulfides. Also
electrostatic techniques may be employed as the primary
separation means, or in addition to the magnetic
separation means. The selective change in surface characteristics
changes the electrical conductivity of the
particle in analogous fashion to changing the particle's
magnetic characteristics. Additionally, due to the fact
that the sulfide or metal oxide surface characterisitcs
have been selectively altered, the sulfides or metal oxides
are often more amenable to processes such as flotation
and chemical leaching.
EXAMPLE I
Two sets of experiments were made with two different
synthetic ores, 5 percent molybdenite and 3 percent
sphalerite, both mixed with Ottawa sand. The first set of
these samples were all treated for 30 minutess with 8
kilograms of iron carbonyl per metric ton of feed. The
molybdenite ore was treated at a temperature of 140°
C., whereas the sphalerite ore was treated at 135° C.
The second set ofsamples were treated exactly the same
as the flrst set with the exception that prior to the treat"
ment the elemental sulfur present with the sulfides was
removed by prolonged refluxing with petroleum ether.
All the samples were subjected to a wet magnetic sepa7
4,276,081
8
ration process, and the analyses of the products thus with 8 kilograms of iron carbonyl per metric ton of
obtained are presented in Table 1. feed. The second set of samples was pretreated to re·
TABLE I
Elemental
Sulfur, Metal
ppm in Weight Grade Distr,
Mineral Mineral Product (%) (%) Metal (%)
Molybdenite 7S Magnetic 8,6 2,10 Mo 90,8
Nonmagnetic 91.4 0.D2 Mo 9,2
Calculated Feed 100.0 0.20 Mo 100,0
Molybdenite Removed Magnetic 4.9 3.35 Mo 81.2
Nonmagnetic 95.1 0.04 Mo 18.8
Calculated Feed 100,0 0.20 Mo 100.0
Sphalerite 387 Magnetic 14,3 4,20 Zn 67.3
Nonmagnetic 85,7 0,34 Zn 32.7
Calculated Feed 100,0 0,89 Zn 100.0
Sphalerite Removed Magnetic 6,7 3.35 Zn 85.7
Nonmagnetic 93.3 0,04 Zn 14.3
Calculated Feed (00,0 0.26 Zn 100.0
EXAMPLE 2 20 move elemental sulfur by extraction with hot petroleum
ether, followed by treatment with iron carbonyl under
Samples of different minerals were ground to minus the same conditions as the first set. The temperature of
6S mesh and mixed with minus 6S mesh silica sand to the iron carbonyl treatment varied for the different
produce 3 percent synthetic ores. There were two sets minerals and is given in Table 2, along with the comparof
each sample. The first set was treated for 30 minutes ative results of the tests.
TABLE 2
Elemental Temperature
Sulfur in Of Fe(CO)s Metal
Mineral Treatment Weight Grade Distr.
Mineral (ppm) ('C,) Product (%) (%) Metal (%)
Bornite I 140 Magnetic 3.6 29.7 4 78.3
Nonmagnetic 96.4 0,313 Cu 21.7
Calculated Feed 100,0 1.38 Cu 100.0
Bornite Removed 140 Magnetic 1.9 44.5 Cu 62.3
Nonmagnetic 98,1 0.530 Cu 37,7
Calculated Feed 100.0 1.38 Cu 100,0
Cinnabar 190 Magnetic 1.6 48.1 Hg 43.9
Nonmagnetic 98.4 1.0 Hg 56.1
Calculated Feed 100.0 1.75 Hg 100.0
Cinnabar Removed 190 Magnetic 1.7 54.5 Hg 54.1
Nonmagnetic 98.3 [0.8]1. Hg 45.9
Calculated Feed 100,0 [1.71] Hg 100.0
Arsenopyrite 4 125 Magnetic 7.4 1.01 As 31.0
Nonmagnetic 92.6 0.18 As 69.0
Calculated Feed 100.0 0.24 As 100.0
Arsenopyrite Removed 125 Magnetic 4.4 1.56 As 47.3
Nonmagnetic 95.6 0.08 As 52,7
Calculated Feed 100,0 0.14 As 100.0
Smaltite 4 115 Magnetic 1.2 5,37 Co 22.1
Nonmagnetic 98.8 0.23 Co 77.9
Calculated Feed 100.0 0.29 Co 100.0
Smaltite Removed 115 Magnetic 0.9 5.04 Co 31.4
Nonmagnetic 99.1 0.10 Co 68.6
Calculated Feed 100.0 0.14 Co 100.0
Smaltite 4 115 Magnetic 1.2 3.35 Ni 22.5
Nonmagnetic 98.8 0.14 Ni 77.5
Calculated Feed 100.0 0.18 Ni 100.0
Smaltite Removed 115 Magnetic 0.9 3.37 Ni 30.4
Nonmagnetic 99.1 0.Q7 Ni 69.6
Calculated Feed 100.0 0.10 Ni 100.0
Chalcocite 4 140 Magnetic 3.4 50.8 Cu 90.5
Nonmagnetic 96.6 0.188 Cu 9.5
Calculated Feed 100.0 1.89 Cu 100.0
Chalcocite Removed 140 Magnetic 2.7 55.8 Cu 86.8
Nonmagnetic 97.3 0.242 Cu 13.2
Calculated Feed 100.0 1.74 Cu 100.0
Chalcopyrite 110 140 Magnetic 1.8 20.5 Cu 48.4
Nonmagnetic 98,2 0,401 Cu 51.6
Calculated Feed 100.0 0.77 Cu 100.0
Chalcopyrite Removed 140 Magnetic 2.5 20.0 Cu 63.5
Nonmagnetic 97.5 0.295 Cu 36,5
Calculated Feed 100.0 0.78 Cu 100.0
Orpiment 823 110 Magnetic 20.1 2.0 As 40.0
Nonmagnetic 79.9 0.74 As 60.0
Calculated Feed 100.0 0.99 As 100.0
Orpiment Removed 110 Magnetic 26.5 2.06 As 49.7
Nonmagnetic 73.5 0.75 As 50.3
9
4,276,081
10
TABLE 2-continued
Elemental Temperature
Sulfur in Of Fe(CO)s Metal
Mineral Treatment Weight Grade Distr.
Mineral (ppm) ("C.) Product (%) (%) Metal (%)
Calculated Feed 100.0 1.10 As 100.0
Realgar 439 95 Magnetic 23.2 2.02 As 36.5
Nonmagnetic 76.8 1.06 As 63.5
Calculated Feed 100.0 1.28 As 100.0
Realgar Removed 95 Magnetic 22.3 1.13 As 27.4
Nonmagnetic 77.7 0.86 As 72.6
Calculated Feed 100.0 0.92 As 100.0
Pentlandite 4558 105 Magnetic 18.2 0.733 Ni 67.4
in Pyrrhotite Nonmagnetic 81.8 0.079 Ni 32.6
Calculated Feed 100.0 0.198 Ni 100.0
Pentlandite Removed 105 Magnetic 2.8 5.18 Ni 80.6
in Pyrrhotite Nonmagnetic 97.2 0.036 Ni 19.4
Calculated Feed 100.0 0.180 Ni 100.0
Stibnite 8081 85 'Magnetic 7.6 4.82 Sb 47.8
Nonmagnetic 92.4 0.43 Sb 52.2
Calculated Feed 100.0 0.77 Sb 100.0
Stibnite Removed 85 Magnetic 1.3 9.80 Sb 43.7
Nonmagnetic 98.7 0.17 Sb 56.3
Calculated Feed 100.0 0.30 Sb 100.0
Tetrahedrite 24 117 Magnetic 2.9 4.43 Cu S8.8
Nonmagnetic 97.1 0.06 Cu 31.2
Calculated Feed 100.0 0.19 Cu 100.0
Tetrahedrite Removed 117 Magnetic 2.8 4.80 Cu 73.4
Nonmagnetic 97.2 0.05 Cu 26.6
Calculated Feed 100.0 0.18 Cn 100.0
Tetrahedrite 24 117 Magnetic 2.9 0.256 Zn 31.0
Nonmagnetic 97.1 0.017 Zn 69.0
Calculated Feed 100.0 0.024 Zn 100.0
Tetrahedrite Removed 117 Magnetic 2.8 0.287 Zn 67.4
Nonmagnetic 97.2 0.004 Zn 32.6
Calculated Feed 100.0 0.012 Zn 100.0
Tetrahedrite 24 117 Magnetic 2.9 0.78 Ag 85.3
Nonmagnetic 97.1 0.004 Ag 14.7
Calculated Feed 100.0 0.027 Ag 100.0
Tetrahedrite Removed 117 Magnetic 2.8 0.97 Ag 73.4
Nonmagnetic 97.2 0.010 Ag 26.6
Calculated Feed 100.0 0.037 Ag 100.0
Tetrahedrite 24 117 Magnetic 2.9 2.34 Sb 53.4
Nonmagnetic 97.1 0.061 Sb 46.6
Calculated Feed 100.0 0.127 Sb 100.0
Tetrahedrite Removed 117 Magnetic 2.8 2.47 Sb 87.7
Nonmagnetic 97.2 0.010 Sb 12.3
Calculated Feed 100.0 0.078 Sb 100.0
IValues in brackets are calculated from other analyses
EXAMPLE 3
Four samples of a synthetic 3 percent stibnite ore 45
were prepared by mixing minus 6S mesh stibnite ore
with minus 6S mesh silica sand. The resultant 3 percent
stibnite ore contained 274 parts per million of elemental
sulfur. One sample received no pretreatment and was
treated with 8 kilograms of iron pentacarbonyl per 50
metric ton of sample at a temperature of 8S' C. for 30
minutes.
The other samples were pretreated with steam, hot
air or petroleum ether to effect the removal of elemental
sulfur and then treated with iron pentacarbonyl in the 55
same manner as the first sample.
The steam pretreatment consisted of treating the
sample with 250 kilograms of steam per metric ton of
sample at a temperature of 200° C. for one hour. The
pretreatment with hot air to remove elemental sulfur 60
was accomplished by spreading the sample in a thin
layer in metal pans and placing these pans in a forced air
drying oven having a temperature of 225' C. for two
hours. The petroleum ether pretreatment consisted of
removing elemental sulfur from a sample through four 65
extractions with this solvent.
All of the samples, after the iron carbonyl treatment,
were subjected to a wet magnetic separation process.
Analyses of the resulting products are given in Table 3.
TABLE 3
Ele- Antimental
mony
Pre- Sulfur Weight Grade Distr.
treatment (ppm) Product (%) (%) (%)
None 274 Magnetic 8.1 3.56 63.4
Nonmagnetic 91.9 0.181 36.6
Calculated Feed 100.0 0.45 100.0
Steam Magnetic 1.24 27.7 58.1
Nonmagnetic 98.76 0.251 41.9
Calculated Feed 100.0 0.59 100.0
Hot Air Magnetic 0.78 20.1 57.9
Nonmagnetic 99.22 0.115 42.1
Calculated Feed 100.0 0.27 100.0
Petroleum 75 Magnetic 2.17 8.78 64.3
Ether Nonmagnetic 97.83 0.108 35.7
Extraction Calculated Feed 100.0 0.30 100.0
EXAMPLE 4
Samples of a synthetic 3 percent galena ore were
prepared by mixing minus 65 mesh galena are wit4
minus 65 mesh silica sand. The resultant 3 percent galena
ore contained 26 parts per million of elemental
sulfur. One sample received no pretreatment and was
4,276,081
11
treated with 8 kilograms of iron pentacarbonyl per
metric ton of sample at a temperature of 1200 C. for 30
minutes.
The other samples were pretreated with steam, hot
air, petroleum ether or heat plus nitrogen to effect the
removal of elemental sulfur, and then treated with iron
pentacarbonyl in the same manner as the first sample.
The steam, hot air and petroleum ether pretreatments
were done in the same manner as described in Example
12
treated with iron carbonyl. The iron pentacarbonyl
treatment was conducted at 1350 C. for 30 minutes with
a dosage of 8 kilograms of iron carbonyl per metric ton
of sample being injected during the first ten minutes of
5 the treatment. Again, the reactor was purged prior to
and following the treatment with a stream of nitrogen
gas. All of the samples were subjected to a wet magnetic
separation process and analyses of the products
thus obtained are presented below in Table 5.
TABLE 5
Sulfur Tungsten
Contained in Weight Grade Distr.
Test Mineral (ppm) Product (%) (%) (%)
Spiked with sulfur, 50 Magnetic 42.2 0.46 43.9
no pretreatment Nonmagnetic 57.8 0.43 56.1
Calculated Feed 100.0 0.44 100.0
Spiked with sulfur, <I Magnetic 27.0 0.80 48.8
and pretreated Nonmagnetic 73.0 0.31 51.2
Calculated Feed 100.0 0.44 100.0
40
What is claimed is:
1. In a process for beneficiating sulfide ores and metal
oxide ores from gangue, excluding coal, wherein the
metal oxide ore is selected from the group consisting of
bauxite, apatite, and the metal oxides of Groups lIB,
IVB, VB, VIB, VIIB, VIIIB, IB, lIB and IVA, which
contain elemental sulfur, wherein the ore is treated with
a metal containing compound under conditions which
30 cause the metal containing compound to react substantially
at the surface of the metal sulfide or oxide particles
to the substantial exclusion of the gangue particles
so as to alter the surface characteristics of the metal
values thereby causing a selective enhancement of the
35 magnetic susceptibility of one or more metal sulfide or
oxide values of the ore to the exclusion of the gangue in
order to permit a physical separation between the values
and the gangue, the improvement comprising:
removing at least a portion of the elemental sulfur
from the ore prior to its treatment with the metal
containing compound.
2. The process of claim 1 wherein. the means for removing
the elemental sulfur comprises heating the ore
to a temperature of from about 80· C. to about 500· C.
45 for a time period of at least about 0.1 hours.
3. The process of claim 2 wherein the heat pretreatment
step is conducted in the presence of a gas selected
from the group consisting of nitrogen, steam, carbon
monoxide, carbon dioxide, ammonia, air, methane, eth.
ane, propane, butane and other hydrocarbon compounds
which exist in the gaseous state at the pretreatment
temperature.
4. The process of claim 3 wherein the gas is steam.
5. The process of claim 4 wherein the steam pretreatment
is conducted within a temperature range of from
about 100· C. to about SOO· C. for at least about 0.1
hours with from about 1 weight percent to about SO
weight percent water, based on the weight of the ore
being treated.
6. The process of claim 1 wherein the means for removing
elemental sulfur comprises solvent extraction.
7. The process of claim 6 wherein the solvent is selected
from the group consisting of petroleum ether,
carbon tetrachloride, toluene, acetone, ethyl alcohol,
methyl alcohol, ether, carbon disulfide and liquid ammonia.
8. The process of claim 2 or claim 7 wherein the
elemental sulfur concentration of the ore following the
A 150 gram sample of synthetic scheelite ore was
made by blending minus 6S mesh scheelite ore (3 per- 50
cent) in minus 65 mesh silica sand. Since the scheelite
ore contained only trace amounts of sulfur, SO parts per
million of sulfur was added to the sample by dissolving
0.0075 grams of sulfur in petroleum ether, mixing the
sulfur solution with the ore and evaporating the ether. 55
A 50 gram split of this sulfur spiked ore was treated
with iron pentacarbonyl in a rotary glass reactor at a
temperature of 1350 C. for 30 minutes. The iron carbonyl
was injected during the first ten minutes of the
treatment at a dosage of 8 kilograms of iron pentacar- 60
bonyl per metric ton of feed. The reactor was purged
prior to and following this treatment with nitrogen gas.
The remaining 100 grams of scheelite ore was exposed
to a hot air pretreatment. The material was
spread in a 9 inch stainless steel pan and placed in a 65
drying oven at a temperature of 22S0 C. for two hours.
The sample was split with one split being used for the
analysis of elemental sulfur and the other split being
TABLE 4
Elemental
Lead
Pre- Sulfur Weight Grade Distr.
treatment (ppm) Product (%) (%) (%)
None 26 Magnetic 7.3 20.9 81.7
Nonmagnetic 92.7 0.370 18.3
Calculated Feed 100.0 1.87 100.0
Petroleum 4 Magnetic 2.3 23.8 78.1
Ether Nonmagnetic 97.7 0.157 21.9
Extraction Calculated Feed 100.0 0.700 100.0
Hot Air <I Magnetic 0.51 29.6 19.0
Nonmagnetic 99.49 0.645 81.0
Calculated Feed 100.0 0.790 100.0
Steam <I Magnetic 2.3 25.5 79.8
Nonmagnetic 97.7 0.152 20.2
Calculated Feed 100.0 0.74 100.0
Heat Magnetic 3.6 12.0 58.3
and N2 Nonmagnetic 96.4 0.321 4\.7
Calculated Feed 100.0 0.74 100.0
EXAMPLES
3. The pretreatment with heat and nitrogen consisted of
passing nitrogen through the reactor at a flow rate of
one reactor volume of gas every 4.3 minutes. These
conditions were maintained for one hour.
All of the samples, after the iron carbonyl treatment,
were subjected to a wet magnetic separation process. 25
Analyses of the resulting products are given in Table 4.
4,276,081
13
pretreatment for the removal of elemental sulfur is less
than about 100 parts per million.
9. The process of claim 2 or claim 7 wherein the
elemental sulfur concentration following the pretreatment
for the removal of elemental sulfur is less than 5
about 50 parts per million. .
10. In a process for the beneficiation of a metal sulfide
ore or a metal oxide ore from gangue, excluding coal,
wherein the metal oxide ore is selected from the group
consisting of bauxite, apatite, and the metal oxides of 10
Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB and IVA,
which contain elemental sulfur, wherein the ore is
treated with from 0.1 to about 100 kilograms of a metal
containing compound per metric ton of ore at a temperature
within the range of 125· C. less than the general 15
decomposition temperature of the metal containing
compound in a specific system for the ore being treated
for a period of time of from about 0.05 tq about 4 hours
to cause the metal containing compound to react substantially
at the surface of the metal sulfide or oxide 20
particles to the substantial exclusion of the gangue particles
so as to alter the surface characteristics ofthe metal
values thereby causing a selective enhancement of the
magnetic·susceptibility of one or more metal sulfide or
oxide values contained in the ore to the exclusion of the 25
gangue so as to permit a separation between the values
and the gangue, the improvement comprising:
removing at least a portion of the elemental sulfur
from the ore prior to its treatment with the metal
containing compound. 30
11. The process of claim 1 or claim 10 wherein the
metal containing compound is an iron containing compound.
12. The process of claim 11 wherein the iron containing
compound is selected from the group consisting of 35
ferrous chloride, ferric chloride, ferrocene, ferrocene
derivatives, ferrous acetylacetonate, ferric acetylacetonate,
ferric acetylacetonate derivatives and iron carbonyls.
13. The process of claim 12 wherein the means for 40
removing the elemental sulfur comprises heating the ore
to a temperature of from about 80· C. to about 500· C.
for a period of time of at least about 0.1 hours.
14. The process ofclaim 13 wherein the heat pretreatment
step is conducted in the presence of a gas selected 45
from the group consisting of nitrogen, steam, carbon
monoxide, carbon dioxide, ammonia, methane, air, ethane,
propane, butane and other hydrocarbon compounds
in the gaseous state at the pretreatment temperature.
50
15. The process of claim 14 wherein the gas comprises
steam at a temperature of from about 150· C. to
about 350· C. for a time period of at least about 0.25
hours and employed in an amount of from about 5 to
about 30 weight percent water, based on the weight of 55
the ore being treated.
16. The process of claim 10 wherein the means for
removing elemental sulfur comprises solvent extraction.
17. The process of claim 16 wherein the solvent is
selected from the group consisting of carbon tetrachlo- 60
ride, toluene, petroleum ether, acetone, methyl alcohol,
ethyl alcohol, ether, carbon disulfide and liquid ammonia.
18. The process of claim 17 wherein the solvent is
employed in an amount of at least about 0.5 liters of 65
solvent per kilogram of ore.
19. The process of claim 18 wherein the solvent is
petroleum ether.
14-
20. The process of claim 14 wherein the gas is employed
in an amount of 12 cubic meters per hour per
metric ton of ore.
21. The process of claim 20 wherein the gas is nitrogen.
22. The process of claim 13 wherein the elemental
sulfur concentration of the ore following the pretreatment
is less than about 50 parts per million.
23. The process of claim 13 wherein the elemental
sulfur concentration of the ore following the pretreatment
is less than about 10 parts per million.
24. The process of claim 13 wherein the iron containing
compound is employed in an amount of from about
I to about 50 kilograms per metric ton of ore and the
selective magnetic enhancement reaction is carried out
at a temperature within a range of 50· C. less than the
general decomposition temperature of the iron containing
compound in a specific system for a period of time
from about 0.15 to about 2 hours.
25. The process of claim 24 wherein the iron containing
compound is an iron carbonyl and the treatment
process is carried out at a temperature within a range of
IS· C. less than the general decomposition temperature
of the iron carbonyl in the specific system for the ore
being treated.
26. The process of claim 24 wherein the mineral values
are physically separated from the gangue by a magnetic
separation process.
27. The process of claim 24 wherein the mineral values
are physically separated from the gangue by an
electrostatic technique.
28. In a process for the beneficiation of a metal sulfide
ore selected from the group consisting of galena, molybdenite,
sphalerite, bornite, cinnabar, arsenopyrite,
smaltite, chalcocite, chalcopyrite, orpiment, pentlandite,
stibnite and tetrahedrite or a metal oxide ore selected
from the group consisting of bauxite, apatite and
the metal oxides of Groups IIIB, IVB, VB, VIB, VIIB,
VIIIB, IB, IIB and IVA, which contain elemental sulfur,
by treating the ore with from about 1 to about 50
kilograms of an iron containing compound selected
from the group consisting of ferrous chloride, ferric
chloride, ferrocene, ferric acetylacetonate, ferrous acetylacetonate,
and iron pentacarbonyl per metric ton of
ore at a temperature within a range of 125" C.less than
the general decomposition temperature of the iron containing
compound in a specific system for the ore being
treated for a period of time from about 0.15 to about 2
hours to cause the iron containing compound to react
substantially at the surface of the metal sulfide or oxide
particles to the substantial exclusion ofthe gangue particles
so as to alter the surface characteristics of the metal
values thereby causing a selective enhancement of the
magnetic susceptibility of one or more metal sulfide or
oxide values of the ore to the exclusion of the gangue in
order to permit a magnetic separation between the values
in gangue, the improvement comprising:
removing at least a portion of the elemental sulfur
from the ore prior to its treatment with the iron
containing compound.
29. The process of claim 28 wherein the means for
removing the elemental sulfur comprises heating the ore
to a temperature of from about ISO· C. to about 350· C.
for a time period of at least about 0.5 hours.
30. The process of claim 29 wherein the heat pretreat:
ment step is conducted in the presence of a gas selected
from the group consisting of nitrogen, steam, hydrogen,
carbon monoxide, carbon dioxide, ammonia, methane,
16
50. In a process for the belleticiation of sulfide ores
and metal oxide ores from gangue, excluding coal,
wherein the metal oxide ore is selected from the group
consisting of bauxite, apatite, and the metal oxides of
Groups IIIB, IVB, VB, VIB, VIlB, VIIIB, IB, lIB, and
IVA, which contain elemental sulfur, wherein the ore is
treated with an iron carbonyl under conditions which
cause the iron carbonyl to react substantially at the
surface of the metal sulfide or oxide particles to the
substantial exclusion of the gangue particles so as to
alter the surface characteristics of the metal values
thereby causing a selective enhancement of the magnetic
susceptibility of one or more metal sulfide or oxide
values of the ore to the exclusion of the gangue in order
to permit a physical separation between the values and
the gangue, the improvement comprising:
removing at least a portion of the elemental sulfur
from the ore prior to its treatment with the iron
carbonyl.
51. The process of claim 50 wherein the means for
removing the elemental sulfur comprises heating the are
to a temperature of from about 1500 C. to about 3500 C.
for a time period of at least about 0.5 hours.
52. The process of claim 51 wherein the heat pretreatment
step is conducted in the presence of a gas selected
from the group consisting of nitrogen, steam, carbon
monoxide, carbon dioxide, ammonia, air, methane, ethane,
propane, butane and other hydrocarbon compounds
which exist in the gaseous state at the pretreatment
temperature.
53. The process of claim 52 wherein the gas is steam
at a temperature from about 1500 C. to about 3500 C. for
a time period of at least about 0.25 hours with from
about 5 weight percent to about 30 weight percent
water, based 011 the weight of the ore being treated.
54. The process of claim 53 wherein the means for
removing elemental sulfur comprises solvent extraction
with the solvent being selected from the group consist..
ing of carbon tetrachloride, petroleum ether, toluene,
acetone, methyl alcohol, ethyl alcohol, ether, carbon
disulfide, and liquid ammonia.
55. The process of claim 54 wherein the solvent is
petroleum ether which is employed in an amount of at
least about 3 liters per kilogram of ore being treated.
56. The process of claim 51 or claim 52 wherein the
elemental sulfur concentration following the pretreatment
for the removal of elemental sulfur is less than
about 50 parts per million.
57. The process of claim 54 wherein the elemental
sulfur concentration following the pretreatment for the
removal of elemental sulfur is less than about 50 parts
per million.
58. The process of claim 51 or claim 54 wherein the
metal sulfide ore is selected from the group consisting of
galena, molybdenite, sphalerite, bornite, cinnabar, arsenopyrite,
smaltite, chalcocite, chalcopyrite, orpiment,
pentlandite, stibnite and tetrahedrite.
59. The process of claim 53 or claim 55 wherein the
60 metal sulfide ore is selected from the group consisting of
galena, molybdenite, bornite, cinnabar, arsenopyrite,
smaltite, chalcocite, chalcopyrite, orpiment, pentlandite,
stibnite and tetrahedrite.
60. The process of claim 51 or claim 52 wherein the
metal oxide ore is scheelite.
61. The process of claim 16 wherein the elemental
sulfur concentration of the ore following the pretreatment
is less than about 10 parts per million.
50
4,276,081
15
air, ethane, propane, butane, and other hydrocarbon
compounds in the gaseous state at the pretreatment
temperature.
31. The process of claim 30 wherein the gas is steam
at a temperature from about 1750 C. to about 2500 C. for 5
a time period of at least about 0.25 hours and employed
in an amount of from about 10 to about 25 weight percent
based on the weight of the ore being treated.
32. The process of claim 28 wherein the means for
removing elemental sulfur comprises solvent extraction 10
with the solvent being selected from the group consisting
of carbon tetrachloride, petroleum ether, toluene,
acetone, methyl alcohol, ethyl alcohol, ether, carbon
disulfide and liquid ammonia.
33. The process of claim 32 wherein the solvent is 15
petroleum ether which is employed in an amount of at
least about 3 liters per kilogram of ore being treated.
34. The process of claim 29 or claim 31 wherein the
iron containing compound is iron pentacarbonyl employed
in an amount from about 2 to about 20 kilograms 20
per metric ton of ore and the process is conducted at a
temperature within a range of 150 C. less than the general
decomposition temperature of the iron carbonyl in
the specific system for a time period of from about 0.15 25
to about 2 hours and the heat pretreatment for sulfur
removal is conducted at a temperature of from about
1750 C. to about 2500 C. for a time period of at least
about 0.5 hours.
35. The process of claim 33 wherein the iron contain- 30
ing compound is iron pentacarbonyl employed in an
amount of from about 2 to about 20 kilograms per metric
ton of ore and the process is conducted at a temperature
within a range of 150 C. less than a general decomposition
temperature of the iron carbonyl in the specific 35
system for the ore being treated for a time period of
from about 0.15 to about 2 hours.
36. The process of claim 34 wherein the metal oxide
ore is.scheelite.
37. The process of claim 35 wherein the ore is sphal- 40
erite.
38. The process of claim 34 wherein the sulfide ore is
selected from the group consisting of galena, molybdenite,
bornite, cinnabar, arsenopyrite, smaltite, chalcocite,
chalcopyrite, orpiment, pentlandite, stibnite and 45
tetrahedrite.
39. The process of claim 38 wherein the sulfide ore is
galena.
40. The process of claim 38 wherein the sulfide ore is
stibnite.
41. The process of claim 38 wherein the sulfide ore is
bornite.
42. The process of claim 38 wherein the sulfide ore is
chalcocite.
43. The process of claim 38 wherein the sulfide ore is 55
orpiment.
44. The process of claim 38 wherein the sulfide ore is
pentlandite.
45. The process of claim 38 wherein the sulfide ore is
cinnabar.
46. The process of claim 38 wherein the sulfide ore is
arsenopyrite.
47. The process of claim 38 wherein the sulfide ore is
smaltite.
48. The process of claim 38 wherein the sulfide ore is 65
tetrahedrite.
49. The process of claim 30 wherein the gas is nitrogen
and the ore is galena.
• • • • •
18
cite, chalcopyrite, orpiment, pentlandite, stibnite and
tetrahedrite.
67. The process of claim 66 wherein the sulfide ore is
galena.
68. The process of claim 66 wherein the sulfide ore is
stibnite.
69. The process of claim 66 wherein the sulfide ore is
bornite.
70. The process of claim 66 wherein the sulfide ore is
chalcocite.
71. The process of claim 66 wherein the sulfide ore is
orpiment.
72. The process of claim 66 wherein the sulfide ore is
15 pentlandite.
73. The process of claim 66 wherein the sulfide ore is
cinnabar.
74. The process of claim 66 wherein the sulfide ore is
arsenopyrite.
75. The process of claim 66 wherein the sulfide ore is
smaltite.
76. The process of claim 66 wherein the sulfide ore is
tetrahedrite.
4,276,081
17
62. The process of claim 16 wherein the iron containing
compound is employed in an amount of from about
1 to about 50 kilograms per metric ton of ore and the
selective magnetic enhancement reaction is carried out
at a temperature within a range of 50' C. less than the 5
general decomposition temperature of the iron containing
compound in a specific system for the ore being
treated for a period of time from about 0.15 to about 2
hours.
63. The process ofclaim 62 wherein the iron contain- 10
ing compound is an iron carbonyl and the treatment
process is carried out at a temperature within a range of
15' C. less than the general decomposition temperature
of the iron carbonyl in the specific system for the ore
being treated.
64. The process of claim 62 wherein the mineral values
are physically separated from the gangue by a magnetic
separation process.
65. The process of claim 62 wherein the mineral values
are physically separated from the gangue by an 20
electrostatic technique.
66. The process of claim 35 wherein the sulfide ore is
selected from the group consisting of galena, molybdenite,
bornite, cinnabar, arsenopyrite, smaltite, chalco-
25
30
35
40
45
50
55
60
65