United States Patent [19]
Ruskan et al.
[Il]
[45]
4,310,490
Jan. 12, 1982
[54] APPARATUS FOR ENRICHING THE IRON
CARBONYL CONTENT OF A RECYCLE GAS
STREAM
Primary Examiner-Bradley Garris
Attorney, Agent, or Firm-Dennis K. Shelton; Bruce G.
Klaas
A method and apparatus for enriching the iron carbonyl
content of a recycle gas stream produced in an iron
carbonyl decomposition or reaction process to enable
reuse of the recycle gas stream in the iron carbonyl
decomposition or reaction process by cooling the recycle
gas stream, adding carbon monoxide to the recycle
gas stream, compressing the recycle gas stream to a
pressure of about 20 to about 38 atmospheres under
conditions suitable to prevent substantial decomposition
of residual iron carbonyl, and contacting the compressed
gas stream at a temperature of about 650 to
about 1600 C. with a reduced iron containing material in
the presence of hydrogen sulfide under conditions suitable
to produce substantially condensed iron carbonyl.
In a particularly preferred embodiment, the recycle gas
stream is initially split into first and second portions, the
first portion of the recycle gas stream is cooled, enriched
with carbon monoxide, compressed and contacted
with the reduced iron containing material to
produce substantially condensed iron carbonyl, and at
least a portion of the condensed iron carbonyl is vaporized
and then combined with the second portion of the
recycle gas stream to produce an iron carbonyl enriched
gas stream. The iron carbonyl enriched gas
stream may then be reintroduced into the iron carbonyl
decomposition or reaction process.
[75] Inventors: Richard P. Ruskan, Houston, Tex.;
Humayon Z. Zafar, Wichita, Kans.;
Duane N. Goens, Golden, Colo.;
David E. Hyatt, Wheatridge, Colo.;
Charlie W. Kenney, Lakewood, Colo.
[73] Assignee: Pentanyl Technologies, Inc., Boulder,
Colo.
[21] Appl. No.: 192,415
[22] Filed: Sep. 29, 1980
Related U.s. Application Data
[62] Division of Ser. No. 139,422, Apr. II, 1980, Pat. No.
4,250,157.
[51] Int. Cl.3 BOIJ 3/04; BOlJ 8/04
[52] U.S. Cl. 422/188; 422/200;
422/208; 422/235
[58] Field of Search 422/188, 200, 201, 235,
422/208; 423/149, 417; 25/0.5 BA; 252/372
[56] References Cited
U.S. PATENT DOCUMENTS
1,614,625 1/1927 Muller-Cunradi 423/417
1,783,744 12/1930 Mittasch et al. 423/417
1,828,376 10/1931 Muller-Cunradi 423/417
2,086,881 7/1937 Schlecht et al. 423/154
2,378,053 6/1945 Wallis et al. 423/138
3,112,179 11/1963 Schmeckenbecher 423/417
46
42
[57]
48
115
ABSTRACT
15 Claims, 1 Drawing Figure
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94
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108
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16
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108
115
34 18
32
3J
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46 .CJ'.)
A'g-I 42 ~
48 ;; ~
~ 83 -- (1)
=:s
~
/94
113
-
50 r - ./ ~8 III 641 I I I 92 - I ~
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16 P
........
J:"l.
........
\0
28 I 6:1 hI:: 'I r- oc I I r -- dlh I 'J' I I I 00
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10
2
sufficient velocity to prevent deposition of iron carbonyl
on the iron oxide material. U.S. Pat. No.
1,783,744 discloses a similar process wherein higher gas
velocities are utilized in conjunction with lower reac-
5 tion temperature and pressure conditions. U.S. Pat. No.
1,828,376 also utilizes high gas velocities to produce
iron carbonyl by passing carbon monoxide at a pressure
of between 50 and 120 atmospheres over porous iron
lumps at a temperature between 90° and 100° C.
Other attempts at the efficient production of iron
carbonyl have utilized modified reaction materials. For
example, U.S. Pat. No. 2,086,881 discloses a process for
producing iron and nickel carbonyl from sulfur bearing
matte materials preferably between 140° and 300° C.
and at pressures preferably of 50, 100 or 200 atmospheres
or even more. U.S. Pat. No.3, 112, 179 discloses
a process for preparing iron and nickel carbonyl by
mixing nickel oxide powder with sponge iron to form a
mixture containing 50 to 98% by weight of sponge iron
and 50 to 2% by weight of nickel oxide powder, pelletizing
the mixture, reducing the oxides in the pellets, and
then passing a stream of carbon monoxide through the
pellets at a temperature of 70° to 170° C. while maintaining
the carbon monoxide pressure at a sufficiently high
level to prevent substantial decomposition of nickel
carbonyl.
Still other attempts at efficiently producing iron carbonyl
have suggested that the presence of sulfur in an
active form may increase the efficiency of iron carbonyl
production. However, the form of the sulfur bearing
material utilized in such a process appears to be critical
in determining efficiency of iron carbonyl production.
For example, as disclosed in U.S. Pat. No. 2,378,053, ".
.. although as has been recognized, sulfur in the form of
35 sulfides such as nickel sulfide is effective to increase the
velocity of the reaction involved in the production of
nickel carbonyl from reduced nickel, nevertheless the
addition of solid sulfides to reduced iron such as described
hereinbefore is not effective. Furthermore, gaseous
sulfides have been found to be ineffective also in
view of the fact that there is an excessive local action
near the inlet port for the gaseous sulfides and relatively
ineffective action at points remote from the gas inlet.
Thus, it is manifest that sulfides are not effective in
increasing the velocity of the reaction between iron and
carbon monoxide to produce iron carbonyl". U.S. Pat.
No. 2,378,058 then discloses that the reaction between
reduced iron and carbon monoxide can be accelerated
by treating the iron containing material with a soluble
solution ofheavy metal sulfates prior to reduction of the
iron containing material.
While the basic reaction of carbon monoxide gas with
reduced iron containing material to form iron carbonyl
has been known for many years, the prior art processes
for production of iron carbonyl have not proceeded
with sufficient efficiency to enable substantial commercial
production, or have entailed economically prohibitive
reaction conditions or material treatment prior to
production. Thus, several proposed industrial processes
involving the decomposition or reaction of iron carbonyl,
as heretofore described, have not been commercially
feasible.
It has now been determined that iron carbonyl may
be produced in a highly efficient manner enabling its use
on a commercial scale in an iron carbonyl decomposition
or reaction process by cooling a recycle gas stream
produced in an iron carbonyl decomposition or reaction
process to a temperature of about 5° to about 15° c.,
4,310,490
1
APPARATUS FOR ENRICHING THE IRON
CARBONYL CONTENT OF A RECYCLE GAS
STREAM
This is a division ofapplication Ser. No. 139,422, filed
Apr. 11, 1980 now U.S. Pat. No. 4,250,157.
BACKGROUND AND SUMMARY OF THE
INVENTION
This invention relates to a method and apparatus for
enriching the iron carbonyl content of a recycle gas
stream, and more particularly to a method and apparatus
for receiving a recycle gas from an iron carbonyl
decomposition or reaction process and enriching the 15
iron carbonyl content with the gas to enable reuse of the
gas stream in the iron carbonyl decomposition or reaction
process.
It has previously been suggested that highly pure
metallic iron may be produced under the proper condi- 20
tions by passing carbon monoxide over reduced iron
containing material to form iron carbonyl, and then
decomposing the iron carbonyl to deposit iron and release
the carbon monoxide. More recently, it has been
suggested that iron carbonyl decomposition or reaction 25
processes may be useful in the desulfurization of hydrocarbons
such as disclosed in U.S. Pat. No. 2,756,182, in
the removal of sulfur during the gasification of coal,
such as disclosed in U.S. Pat. No. 2,691,573, in the desulfurization
of petroleum crude and primary refinery 30
products, such as disclosed in U.S. Pat. No. 3,996,130, in
the removal of pyrite and ash from coal, such as disclosed
in U.S. Pat. No. 3,938,966, and in the removal of
organic sulfur from coal, such as disclosed in U.S. Pat.
No. 4,146,367.
A typical process for producing a metallic carbonyl
entails passing carbon monoxide, or gases containing a
substantial portion of carbon monoxide, over the metal
of which the carbonyl is to be formed. The metal to be
acted upon by carbon monoxide is typically obtained by 40
gaseous reduction of an oxide of the metal. Although
other carbonyls may be formed in this manner, substantial
commercial production appears to have been limited
to nickel carbonyl, since the reaction may take
place at relatively low pressure and temperatures, as for 45
example at atmospheric pressure and a temperature of
about 40° C. to about 50° C. Iron carbonyl, on the other
hand, is much more difficult to form, and is typically
produced by the reaction of carbon monoxide with iron
generally obtained by the reduction of iron ore, but at 50
temperatures and pressures much higher than are required
for the production of nickel carbonyl from reduced
nickel. For example, temperatures on the order
of 175° C. or higher and pressures in the range offrom
100 to 200 atmospheres, or even as high as 2,000 atmo- 55
spheres, have been employed in attempts to make the
reaction proceed sufficiently rapidly to make iron carbonyl
production efficient.
Several attempts have been made to efficiently produce
iron carbonyl by modifying reaction conditions. 60
For example, U.S. Pat. No. 1,614,625 discloses a process
for producing iron carbonyl by passing carbon monoxide
under a pressure of about 200 atmospheres over iron
metal at a temperature of about 200° C. U.S. Pat. No.
1,759,268 discloses a process for producing iron car- 65
bonyl by passing carbon monoxide at a pressure of
about 50 atmospheres or more over reduced oxides of
iron at a temperature of about 100 to about 200° C. at a
4-
1 to about 8%, and most preferably about 4 to about 6%
by volume residual iron carbonyl.
Although the recycle gas stream may be processed as
a whole in accordance with the inventive concepts, it is
5 a presently particularly preferred embodiment to initially
split the recycle gas stream into at least first and
second portions, to treat one portion to produce iron
carbonyl and then to recombine the separate portions of
the recycle gas stream. Thus, although the inventive
10 concepts are hereinafter described in connection with a
split recycle gas stream, it is to be understood that the
recycle gas stream may also be processed as a whole. In
accordance with the foregoing, the recycle gas stream is
initially split into two portions, a first portion of which
15 is processed, as hereinafter further described, to produce
additional iron carbonyl, and a second portion
which is enriched with vaporized iron carbonyl and
returned directly to the iron carbonyl reaction or decomposition
process.
The first portion of the recycle gas stream is treated
by cooling the first portion to a temperature of about 5°
to about 15° C., preferably about 10° C. During cooling,
a portion of the iron carbonyl and water in the gas
stream is condensed, and the liquid iron carbonyl is
25 recovered and stored for subsequent use. Carbon monoxide
is then added to the cooled gas stream to form a
carbon monoxide enriched recycle gas stream.
The carbon monoxide enriched gas stream is compressed
to a pressure of about 20 to about 38 atmo-
30 spheres, more preferably about 27 to about 36 atmospheres,
and most preferably about 30 to about 34 atmospheres,
under conditions suitable to prevent the decomposition
of a substantial amount of the iron carbonyl
remaining in the gas stream. Iron carbonyl in the
carbon monoxide enriched gas stream may decompose
under certain combinations of gas stream temperature,
pressure and iron carbonyl content. In particular, decomposition
of iron carbonyl may occur during compression
of the carbon monoxide enriched gas stream
due to a temperature rise resulting from the adiabatic
heat of compression and/or the heat of mechanical
inefficiency of the compressor. However, it has been
found that iron carbonyl decomposition can be substantially
reduced by compressing the gas stream in multiple
stages with interstage cooling of the gas stream to a
temperature of about 5° to about 15° C. In a presently
particularly preferred embodiment, the gas stream is
compressed to the desired degree in four separate stages
with relatively low initial stage compression ratios and
with interstage cooling to a temperature of about 10° C.
After compression, the first portion of the recycle gas
stream is contacted with an activated, reduced iron
containing material at a temperature of about 6SO to
about 160° C., more preferably about 125° to about 150°
C., and most preferably about 130° to about 135° C.
Suitable iron containing materials include all iron containing
materials in which the iron is capable of being
reduced to a high degree. For example, sponge iron has
been found to be particularly well suited as an iron
containing material in the process of the invention due
to its partially prereduced condition and commercial
availability, although other iron containing materials
may be employed.
In order to activate the sponge iron, or other iron
containing material, the sponge iron is charged into a
sealable vessel and the vessel is sealed and evacuated or
purged, such as with a steam ejector, vacuum device,
suitable purge gas or the like. The sponge iron is then
4,310,490
DESCRIPTION OF THE PRESENTLY
PREFERRED EMBODIMENTS
As used herein, the term "iron carbonyl" means iron
compounds containing a plurality of carbonyl groups.
Although it is presently thought that the predominate
form of iron carbonyl produced by the process of the 35
invention and present in the recycle gas stream is iron
pentacarbonyl, Fe(CO)s, it is further expected that
lesser amounts of other iron carbonyls, such as iron
butacarbonyl, Fe(CO)4, iron nonacarbonyl, Fe2(CO)9,
iron dodecacarbonyl, Fe3(CO)12, etc., may be present 4Q
both in the condensed iron carbonyl and in the recycle
gas stream. All such compounds are intended to be
included in the term "iron carbonyl". Although it is not
fully understood at this time, it may be possible that the
equilibrium existing between various iron carbonyl 45
forms under the process conditions disclosed herein
may contribute to both enhanced iron carbonyl yields
and effectiveness of the recycle gas stream in the iron
carbonyl decomposition or reaction process.
Recycle gas to be treated according to the process of 50
the present invention can be any by-product gas produced
as a result of an iron carbonyl reaction or decomposition
process. For example, the recycle gas may be
produced by reaction iron carbonyl with iron disulfide
to produce "iron-rich disulfide" in the coal beneficiat- 55
ing process disclosed in U.S. Pat. No. 3,938,966 of Kindig
et aI., by reacting the iron carbonyl with coal to
obtain organic sulfur removal, or from other processes
in which iron carbonyl is reacted or decomposed to
form iron or iron compounds and carbon monoxide. A 60
typical recycle gas stream suitable for use in connection
with the inventive concepts comprises residual, unreacted
or undecomposed iron carbonyl, carbon monoxide
produced in the iron carbonyl reaction or decomposition
process, and possibly other by-product or leakage 65
gases such as nitrogen, carbon dioxide, hydrogen and
water vapor. The recycle gas stream may comprise, for
example, about 0.0 to about 10%, more preferably about
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic drawing of the process and
apparatus of an illustrative embodiment of the present
invention.
3
adding carbon monoxide to the cooled gas stream to
produce a carbon monoxide enriched gas stream, compressing
the carbon monoxide enriched gas stream to a
pressure of about 20 to about 38 atmospheres under
conditions suitable to prevent the decomposition of
substantial amounts of iron carbonyl in the carbon monoxide
enriched gas stream, and contacting the compressed
gas stream at a temperature of about 65° to
about 160° C. with a reduced iron containing material in
the presence of an iron carbonyl production enhancing
amount of hydrogen sulfide under conditions suitable to
producing substantially condensed iron carbonyl. Preferably,
the recycle gas stream is split into first and second
portions, the first portion is cooled, enriched with
carbon monoxide, compressed and contacted with the
reduced iron containing material to produce substantially
condensed iron carbonyl, and at least a portion of
the condensed iron carbonyl is vaporized and combined
with the second portion of the recycle gas stream to
produce an iron carbonyl enriched recycle gas stream. 20
The iron carbonyl enriched recycle gas stream may
then be reintroduced into the iron carbonyl decomposition
or reaction process.
132
146
148
157
158
159
Critical
Temperature
('C. )
6
TABLE I
20
27
30
34
36
38
Pressure
(Atmospheres)
It has been found that a majority of the iron carbonyl
formed in the vessel condenses under the foregoing
reaction conditions providing a driving force for the
forward iron carbonyl generation reaction, while not
substantially impeding the kinetic mechanism which is
generally thought to require migration of carbon monoxide
molecules to active iron sites. The reaction vessel
is preferably sized and designed so that substantially all
of the carbon monoxide in the compressed gas stream is
converted to iron carbonyl. After contacting the compressed
gas stream with sponge iron in the reaction
vessel, the gas stream, comprising various inert gases,
carbon monoxide and iron carbonyl is cooled, such as in
a tail gas cooler, to condense and recover additional
iron carbonyl.
The activity of the iron containing material in the
reaction. vessel has been found to decrease over time
due to phenomena which are not completely understood,
but which may result from reaction of iron in the
iron containing material with trace quantities of oxygen
in the compressed recycle gas stream, from a build-up of
carbon on the iron bed, or from the physical blocking of
active iron sites by substances such as hydrocarbon
material which are typically present in carbon monoxide
containing synthesis gas. It has been determined that
any such decrease in iron activity can be at least partially
reversed by the presence of iron carbonyl production
enhancing amounts of hydrogen sulfide during the
carbonylation reaction. Enhancing amounts of hydrogen
sulfide may be maintained in the reaction vessel by
the intermittent or continuous injection of hydrogen
sulfide into the compressed recycle gas stream or by the
45 utilization of trace hydrogen sulfide and other effective
sulfur containing gases which may be present in the
carbon monoxide synthesis gas. In extreme cases where
the carbonylation reaction has resulted in substantial
deactivation of the iron containing material, it has been
determined that restoration of activity may be obtained
by further reduction of the iron containing material
with reducing gas, as hereinbefore described, followed
by reactivation with hydrogen sulfide.
The condensed iron carbonyl produced according to
the foregoing process is then vaporized and combined
with the second portion of the recycle gas stream to
provide an iron carbonyl enriched gas stream comprising,
for example, about S to about 20%, more preferably
about 6 to about 14%, and most preferably about 8 to
about 12%, by volume iron carbonyl, for reuse in the
iron carbonyl reaction or decomposition process. Vaporization
of the condensed iron carbonyl may be obtained,
for example, by heating the condensed iron carbonyl
to a temperature of about lOS· to about 140· C.
under a pressure of, for example, about 32 atmospheres,
and thereafter reducing the pressure to about 1 atmosphere
while introducing the iron carbonyl into the
second portion of the recycle gas stream, whereby the
4,310,490
Fe+5C(),o±Fe(CO)s
5
preheated to a temperature ofabout 600· to about 760·
C., preferably to about 650· C. at a pressure of about 2
to about 3 atmospheres, such as by passing heated nitrogen
through the sealed vesseL When the sponge iron
has been preheated to the desired temperature level,· a 5
reducing gas, such as hydrogen, carbon monoxide or
mixtures thereof, is slowly passed through the column
to further reduce the sponge iron and to activate the
sponge iron for subsequent reaction with the compressed
recycle gas stream. Due to its greater ability to 10
reduce iron at a given temperature level, hydrogen, and
reducing gases comprising a relatively large hydrogen
concentration, are the presently preferred reducing gas
for use in connection with the present invention. Water
vapor and other gaseous materials produced during 15
sponge iron reduction, together with unconsumed hydrogen,
are purged from the top of the sealed vessel.
When the purged gas stream no longer evidences the
production of additional water vapor or carbon dioxide,
the sponge iron is cooled to the desired reaction temper- 20
ature of about 65· to about 160· C., more preferably
about 12S· to about ISO· C., and most preferably to
about 130· to about l3S· C., under a protective blanket
ofthe reducing gas or other inert gas to prevent oxidation
of the reduced sponge iron. Final activation of the 25
sponge iron is then obtained by charging the sponge
iron in the vessel with an iron carbonyl production
enhancing amount of hydrogen sulfide. Effective
amounts of hydrogen sulfide have been found to be
about 0.2% to about 0.4%, preferably about 0.3%, of 30
sulfur per unit of sponge iron in the vessel, when diluted,
for example, in the cooling blanket of reducing or
inert gas. The activated, reduced sponge iron, or other
iron containing material is then contacted with the compressed,
carbon monoxide enriched recycle gas stream 35
at a temperature of about 6S· to about 160· C., more
preferably about l2S· to about ISO· C., and most preferably
about 130· to about l3S· C., and at apressure of
about 20 to about 38 atmospheres, more preferably
about 27 to about 36 atmospheres, and most preferably 40
about 30 to about 34 atmospheres, by slowly passing the
compressed recycle gas stream over the sponge iron to
produce iron carbonyl, predominately by the reaction:
The exothermic heat of reaction formed during iron
carbonyl production is removed to maintain the sponge
iron at the desired temperature leveL
It is critical to the efficient operation of the present 50
process that the operating carbonylation temperature
for any given pressure be maintained at a level less than
that at which phase equilibria and chemical equilibria
commonly exist. If the operating temperature exceeds
this critical level, a reVerse carbonylation reaction may 55
occur. If the operating temperature is approximately
equal to this critical level, the forward carbonylation
reaction will proceed until iron carbonyl gas saturation
is obtained, at which point chemical equilabria is
reached and the forward reaction will substantially 60
stop. If the operating temperature is maintained below
this· critical level, the forward carbonylation reaction
proceeds, iron carbonyl gas saturation is ultimately
reached, and thereafter iron carbonyl condenses, favoring
continuation of the forward reaction since chemical 65
equilibria is not obtained; Based upon current information,
it appears that the critical temperature levels for
various given pressure levels are as follows:
8
duit means 44 at a temperature of about 185° to about
190° C.
Cooling means 46 is provided in the system for receiving
the compressed carbon monoxide enriched recycle
gasstream from the compressor means 42 through
conduit means 44 and for cooling the recycle gas stream
to the desired carbonylation temperature of about 65° to
about 160° C. After cooling, the recycle gas stream is
transferred through conduit means 48 to an activated
reduced iron containing material filled reaction chamber
means formed by a suitable reaction vessel, such as
reaction vessel 50, for carrying out the carbonylation
reaction.
In the illustrative, presently preferred embodiment of
FIG. 1, the system comprises three separate reaction
chamber means formed by reaction vessels 50, 52, 54,
with the reaction vessels 50, 52 being shown on stream
in the production of iron carbonyl, and the reaction
vessel 54 being shown as used for iron containing material
reduction, as is hereinafter further described. In this
manner, the production of iron carbonyl according to
the present invention may be operated continuously by
simultaneously activating and reducing iron containing
material in, for example, reaction vessel 54, while carrying
out iron carbonyl production in, for example, reaction
vessels 50, 52. Then, when the reduced iron content
of, for example, reaction vessel 50 becomes substantially
depleted, the reaction vessel 50 may be taken off stream,
the functional position of reaction vessel 52 can be
shifted to that previously occupied by reaction vessel
50, the reaction vessel 54 containing newly reduced iron
containing material may be placed on stream in the
functional position previously occupied by reaction
35 vessel 52, and the reaction vessel 50 may be filled with
fresh iron containing material and placed in the reduction
cycle in the functional position previously occupied
by reactor vessel 54. Although illustrative embodiment
of FIG. 1 is presently particularly preferred in that
it permits continuous operation of the system by rotation
of the functional position of reaction vessels SO, 52,
54, it is contemplated that the inventive concepts may
be employed in a batch or continuous system utilizing
one or two reaction vessels, or in a batch or continuous
45 system utilizing four or more reaction vessels.
From the foregoing, it is apparent that the system of
the invention further comprises means, such as reaction
vessels 50, 52, for receiving compressed carbon monoxide
enriched recycle gas from cooler means 46 and for
providing a reaction chamber containing activated,
reduced iron containing material wherein the iron containing
material is contacted with the compressed recycle
gas at a temperature of about 65° to about 160° C.,
more preferably about 125° to about 150° C., and most
preferably about 130° to about 135° C., and at a pressure
of about 20 to about 38 atmospheres, more preferably
about 27 to about 36 atmospheres, and most preferably
about 30 to about 34 atmospheres. The reaction vessels
50, 52, 54 are preferably of vertically oriented, cylindrical
design so as to form reaction columns. For example,
the reaction columns may be about 3 feet in diameter,
about 22 feet in length, provided with coils or the like
adapted for the passage of steam or water therethrough
to cool the reduced iron containing material and to
maintain the reaction temperature within desired limits,
as hereinafter further described, and adapted to withstand
both the reduction and carbonylation temperature
and pressure conditions of the process.
4,310,490
7
iron carbonyl is simultaneously vaporized and combined
with the second portion of the recycle gas stream.
The foregoing process may be more fully understood
in connection with FIG. 1, which is a schematic drawing
of a presently preferred embodiment of the appara- 5
tus of the invention. A by-product gas stream produced
by an iron carbonyl reaction or decomposition process
and to be treated by the system of the present invention
is introduced into the treatment system through recycle
gas input conduit means 10. The recycle gas is split into 10
a first portion which is transferred to cooling means 12
through conduit means 14, and a second portion which
is transferred to iron carbonyl vaporization means 16
through "conduit means 18.
Cooling means 12 for cooling the first portion of the 15
recycle gas stream to a temperature of about 5° to about
15° C, preferably about 10° C., may comprise two or
more separate gas coolers 20, 22, as shown in FIG. 1, or
may comprise a single gas cooler. In the illustrative
embodiment of FIG. 1, cooling means 12 is particularly 20
adapted to receiving an input recycle gas stream at
temperatures on the order of 185° C, or higher, and
cooling the gas stream to temperatures on the order of
50° C. in the first gas cooler 20 and to the desired tem- 25
perature of about 5° to about 15° C. in the second gas
cooler 22. During cooling of the recycle gas, a portion
of the iron carbonyl in the recycle gas will condense in
the coolers 20, 22. Any such condensed iron carbonyl is
recovered from the coolers 20, 22 and transferred 30
through conduit means 24, 26, respectively, and conduit
means 28 to intermediate iron carbonyl collection
means 30, and through conduit means 32 to iron carbonyl
storage means 34 for subsequent use, as will be
hereinafter further described.
After cooling to the desired temperature, the cooled
recycle gas is transferred out of gas cooler 22 through
conduit means 36. A carbon monoxide containing gas is
introduced into the cooled recycle gas stream from
carbon monoxide source 38 through conduit means 40 40
to produce a carbon monoxide enriched recycle gas
stream in the conduit means 36. The carbon monoxide
enriched recycle gas stream is then transferred through
the conduit means 36 to recycle gas compressor means
42.
The system further comprises recycle gas compressor
means 42 for compressing the carbon monoxide enriched
recycle gas to a pressure of about 20 to about 38
atmospheres under conditions suitable to prevent the
decomposition of a substantial amount of iron carbonyl 50
in the carbon monoxide enriched recycle gas stream. As
previously set forth, iron carbonyl decomposition is
minimized by compressing the recycle gas stream in
multiple stages with interstage cooling of the partially
compressed gas stream. In a presently particularly pre- 55
ferred embodiment, recycle gas compressor means 42
comprises a four stage recycle gas compressor having a
relatively low first stage compression ratio of, for example,
about 1.6, a relatively high last stage compression
ratio of, for example about 3.9, and incrementally in- 60
creasing intermediate stage compression ratios of, for
example, about 2.1 and 2.8, respectively. The compressor
means 42 further comprises three interstage gas
coolers (not shown) adapted to cool the partially compressed
recycle gas stream to a temperature of about 5° 65
to about 15° C. between the individual stages of the
recycle gas compressor, the recycle gas stream being
transferred out of the compressor means through con4,310,490
10
removed from the condenser means 79 such as through
conduit means 83 for subsequent treatment prior to
discharge into the atmosphere. Upon determination that
no iron carbonyl remains in the reaction vessel 54, the
spent iron containing material is discharged from the
vessel and the vessel is filled with suitable, fresh iron
containing material, such as sponge iron or the like. The
filled vessel is then sealed and air is evacuated from the
vessel through conduit means 78, such as by introducing
steam through conduit means 80 into ejector means
82.
The system further comprises heater means, such as
nitrogen supply source 84, heater 86 and interconnecting
conduit means 88, 90, for heating the iron containing
material to a temperature sufficient for enabling efficient
reduction of the iron containing material. It has
been found that the iron containing material may be
efficiently reduced at temperatures of about 6200 to
about 7600 C., preferably about 6500 C. In the illustrative
embodiment of FIG. 1, nitrogen from nitrogen
supply source 84 is transferred through conduit means
88 into heater 86 and then through conduit means 90
into reaction vessel 54, where the heated nitrogen heats
the iron containing material to the desired temperature
level. In order to conserve nitrogen, nitrogen recycle
means 91 may additionally be provided for recycling
the nitrogen from the vessel through the heater and
back into the vessel. In the illustrative embodiment of
FIG. 1, the nitrogen recycle means comprises pump
means 92, nitrogen cooler means 94 for receiving heated
nitrogen from the vessel 54 and cooling the nitrogen
during the last portions of the heating cycle to a temperature
within the operating limits of the pump means 92,
and conduit means 96, 98 and 100 operatively interconnecting
vessel 54, nitrogen cooler means 94, pump
means 92 and heater 86. When the iron containing material
has been heated to the desired level, the nitrogen
supply is closed off and a reducing gas, such as hydrogen,
heated to a temperature of about 620· to about 7500
C., preferably about 6500 C., is introduced into the
vessel 54, such as from hydrogen supply source 102,
through conduit means 104, heater 86 and conduit
means 90, to reduce the iron in the iron containing
material to a highly metalized state. Water vapor produced
during iron reduction, and unconsumed hydrogen,
are purged from the reaction vessel 54, such as
through conduit means 78. When the desired degree of
iron reduction has been obtained in reaction vessel 54,
the vessel 54 is ready to be used for the production of
50 iron carbonyl, as heretofore described.
From the foregoing, it is apparent that the system of
the invention provides for continuous production of
iron carbonyl by utilizing two reaction vessels, such as
vessels 50, 52 for iron carbonyl production while simultaneously
reducing fresh iron containing material in a
third reaction vessel, such as reaction vessel 54. In this
manner, when the metalized iron content of the material
in one carbonylation vessel, such as vessel 50, becomes
substantially depleted, it may be pulled off-line from the
carbonylation process, replaced in functional position
by the second carbonylation vessel, such as vessel 52,
while the newly reduced reaction vessel, such as vessel
54, is brought in line in the carbonylation process in the
functional position formerly held by the vessel 52, all
without substantial interruption of the iron carbonyl
production process.
The apparatus further comprises vaporization means
16 for vaporizing the condensed iron carbonyl and re-
9
The temperature of vessels 50, 52 is adjusted, for
example, to about 650 C. to about 1600 C. at a pressure
of about 20 to about 38 atmospheres by passing steam
through coils in the reaction vessels, and then an iron
carbonyl production enhancing amount of hydrogen
sulfide from hydrogen sulfide supply source 56 is introduced
into the vessels 50, 52 through conduit means 58,
60. The compressed, carbon monoxide enriched gas is
then introduced into the top of reaction vessel 50
through conduit means 48 and allowed to pass slowly 10
downwardly through the reaction vessel where it
contacts the activated, reduced iron containing material
and reacts with the material to form iron carbonyl.
Excess heat produced by the exothermic heat of reaction
is removed from the reaction vessel, such as by 15
passing water or the like through the coils in the reaction
vessel. A majority of the iron carbonyl formed in
reaction vessel 50 condenses under the foregoing carbonylation
conditions, and is removed from reaction vessel
50 through conduit means 62. Any unreacted gas, 20
vaporized iron carbonyl, and other tail gases, are removed
from the bottom of reaction vessel 50 and transferred
to the top of reaction vessel 52 through conduit
means 64. The tail gases from reaction vessel 50 are then
passed slowly downwardly through reaction vessel 52 25
where they are allowed to contact the activated, reduction
iron containing material in reaction vessel 52 under
the same reaction conditions and react with the material
to form additional iron carbonyl. Similarly to reaction
vessel 50, excess heat produced by the exothermic heat 30
of reaction is removed from reaction vessel 52. A majority
of the newly formed iron carbonyl condenses in
the reaction vessel 52 and is removed from the bottom
of the reaction vessel 52 through conduit means 66. The
apparatus may further comprise tail gas cooler means 68 35
for receiving tail gas from reaction vessel 52, such as
through conduit means 69 and cooling the tail gas to
condense additional iron carbonyl. Uncondensed gases
are transferred away from cooler means 68 through
conduit means 70 for subsequent treatment prior to 40
discharge or disposal, while condensed iron carbonyl is
recovered and removed from the cooler means through
conduit means 72.
Condensed iron carbonyl recovered from reaction
vessels 50, 52 and tail gas cooler means 68 is transferred 45
through conduit means 62, 66, 72 and received by receiver
means 74 for receiving the condensed iron carbonyl
and maintaining the iron carbonyl at a temperature
and pressure level about equal to that within reaction
vessels 50, 52.
The presently preferred, illustrative embodiment
shown in FIG. 1 further comprises reaction vessel 54,
which is shown as used for iron containing material
reduction in FIG. 1. The reaction vessel 54, having been
previously utilized in the carbonylation cycle for the 55
production of iron carbonyl, contains material having a
substantially reduced metallic iron content. The reaction
vessel 54 is depressurized and slowly and carefully
purged with air from air supply means 76 to deactivate
the iron heel, to destroy residual iron carbonyl, and to 60
cool the iron heel in the reaction vessel. The purged
gases are removed from the vessel through conduit
means 711 and passed through condenser means 79 for
condensing any residual iron carbonyl from the purge
gas stream. Any condensed iron carbonyl is transferred 65
from condensor means 79 to iron carbonyl collection
means 30 such as through conduit means 81, while the
substantially iron carbonyl free purge gas stream is
4,310,490
11
combining the vaporized iron carbonyl with the second
portion of the recycle gas stream to produce an iron
carbonyl enriched gas stream for use in the iron carbonyl
decomposition or reaction process. As shown in
FIG. 1, condensed iron carbonyl recovered from reac- 5
tion vessels 50, 52 and collected in receiver means 74 is
transferred from the receiver means to the vaporization
means 16 through conduit means 106, 108. Vaporization
means 16 comprises heater means, such as heater 110, in
the conduit means 108 for preheating the condensed 10
iron carbonyl to a temperature of about 105° to about
140° C., at a pressure of about 20 to about 38 atmospheres,
and vaporization column means 111 for receiving
iron carbonyl from heater 110, reducing the pres- 15
sure of the iron carbonyl to about 1 atmosphere to vaporize
the iron carbonyl and combining the vaporized
iron carbonyl with the second portion ofthe recycle gas
stream. Preheated iron carbonyl from heater 110 is
introduced into the vaporization column means and is 20
vaporized therein. The second portion of recycle gas is
simultaneously introduced into the vaporization column
means through conduit means 18 and is combined with
the vaporized iron carbonyl in any desired proportions
to produce an iron carbonyl enriched gas stream. The 25
enriched gas stream, comprising, for example, 10% iron
carbonyl, is transferred out of vaporization means 16
through conduit means 113 and is recycled to the iron
carbonyl decomposition or reaction process. Any iron
carbonyl which condenses in vaporization column 30
means 111 is collected in a bottom portion thereof and
is transferred to iron carbonyl collection means 30 such
as through conduit means 115.
During periods of excess iron carbonyl production or
vaporization means shut-down, condensed iron car- 35
bonyl is transferred from receiver means 74 through
conduit means 106, 112 to iron carbonyl storage means
34. Cooling means, such as cooler 114, are preferably
provided in the conduit means 112 for cooling the iron
carbonyl to a temperature less than about 90° C. prior to 40
transferring the iron carbonyl to the storage means.
During periods of iron carbonyl production shortage,
make-up iron carbonyl is transferred from storage
means 34 to vaporization means 16 through conduit
means 106, 108 as required. 45
While the foregoing process and apparatus have been
described in connection with various presently preferred
and illustrative embodiments, various modifications
may be made without departing from the inventive
concepts. All such modifications are intended to be 50
within the scope of the appended claims, except insofar
as limited by the prior art.
What is claimed is:
1. An apparatus for enriching the iron carbonyl con- 55
tent of a recycle gas stream comprising residual iron
carbonyl and carbon monoxide and produced in an iron
carbonyl decomposition or reaction process to enable
reuse of the recycle gas stream in the iron carbonyl
decomposition or reaction process, comprising: 60
recycle gas stream splitting means for receiving a
recycle gas stream from an iron carbonyl decomposition
or reaction process and splitting the gas
stream into a first portion and a second portion;
cooler means for cooling the first portion of the recy- 65
cle gas stream to a temperature of about 5° to about
15° C., thereby condensing at least a portion of the
residual iron carbonyl in the gas stream;
12
carbon monoxide supply means for supplying carbon
monoxide to the cooled first portion of the gas
stream;
compressor means for compressing the carbon monoxide
enriched gas stream to a pressure of about 20
to about 38 atmospheres under conditions suitable
to prevent the decomposition of substantial
amounts of iron carbonyl in the gas stream;
reaction vessel means containing reduced iron containing
material for receiving the gas stream from
the compressor means and for providing a reaction
chamber wherein the gas stream is contacted with
the iron containing material at a temperature of
about 65° to about 160° C. at a pressure of about 20
to about 38 atmospheres to produce substantially
condensed iron carbonyl;
vaporization means for vaporizing the condensed
iron carbonyl;
combination means for combining at least a portion of
the vaporized iron carbonyl with the second portion
of the recycle gas stream to produce an iron
carbonyl enriched recycle gas stream; and
fluid communication means providing fluid communication
between the recycle gas stream splitting
means, the carbon monoxide supply means, the
cooler means, the compressor means, the reaction
vessel means, the vaporization means and the combination
means.
2..The apparatus of claim 1 wherein the cooler means
comprises a first gas cooler and a second gas cooler.
3. The apparatus of claim 2 wherein the first gas
cooler includes means for cooling the first portion of the
recycle gas stream to a temperature of about 50° C.
4. The apparatus of claim 2 wherein the second gas
cooler includes means for cooling the first portion ofthe
recycle gas stream to a temperature of about 5° to about
15° C.
5. The apparatus of claim 1 which further comprises
collection means for collecting iron carbonyl condensed
in the cooler means.
6. The apparatus of claim 1 wherein the compressor
means comprises multiple stage compressor means for
compressing the carbon monoxide enriched gas stream
in multiple compression stages and for cooling the carbon
monoxide enriched gas stream between compression
stages.
7. The apparatus of claim 6 wherein the multiple
stage compressor means comprises a four stage gas
compressor.
8. The apparatus of claim 7 wherein the four stage gas
compressor has a relatively low first stage compression
ratio, a relatively high last stage compression ratio and
incrementally increasing intermediate stage compression
ratios.
9. The apparatus of claim 6 wherein the multiple
stage compressor means includes means for cooling the
carbon monoxide enriched gas stream to a temperature
of about 5° to about 15° C. between the compression
stages.
10. The apparatus of claim 1 wherein the reaction
vessel means comprises at least three reaction vessels, at
least two of the reaction vessels being adapted to provide
the reaction chamber at anyone time, and the
remaining reaction vessels being adapted to provide a
chamber for the reduction of iron containing material.
11. The apparatus of claim 10 wherein the reaction
vessels are formed by vertically oriented cylindrical
columns.
4,310,490
13
12. The apparatus of claim 11 wherein the reaction
vessels further comprise coils adapted for the passage of
steam or water therethrough to cool the reduced iron
containing material.
13. The apparatus of claim 10 which further com·
prises heater means for heating iron containing material
in the reaction vessels to a temperature sufficient for
enabling reduction of the iron containing material.
14. The apparatus of claim 13 wherein the heater
means comprises a nitrogen supply source, a heater and
14
conduit means providing fluid communication between
the nitrogen source, the heater and the reaction vessels.
15. The apparatus of claim 1 wherein the vaporization
means comprises heater means for heating the con·
5 densed iron carbonyl to a temperature of about 105° to
about 140° C. at a pressure of about 20 to about 38
atmospheres, and vaporization column means for reo
ceiving iron carbonyl from the heater means, reducing
the pressure of the iron carbonyl to about 1 atmosphere
10 to vaporize the iron carbonyl and combining the vaporized
iron carbonyl with the second portion of the recycle
gas stream.
* * * * *
15
20
25
30
35
40
45
50
55
60
65
l&Qջhih^IPAmal;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none'>Nonmagnetic 98.4 1.85 95.1
Calculated Feed 100.0 1.92 100.0
Yes 150 15 Magnetic 13.2 12.7 93.1
Nonmagnetic 86.8 0.143 6.9
Calculated Feed 100.0 1.80 100.0
No 150 15 Magnetic 0.73 14.8 6.0
Nonmagnetic 99.27 1.71 94.0
Calculated Feed 100.0 1.81 100.0
Yes 150 90 Magnetic 30.4 5.28 88.2
Nonmagnetic 69.6 0.308 Il.a
Calculated Feed 100.0 1.82 100.0
No 150 90 Magnetic 0.44 8.58 2.1
4,289,529
17 18
TABLE 10-continued
Pretreatment
Fe(COls Temperature Time Weight Grade Zinc
Treatment ('C,) (minutes) Product (%) (%) Distr.
Nonmagnetic 99.56 1.74 97.9
Calculated Feed 100.0 1.77 100.0
Yes none none Magnetic 36.5 3.50 70.5
Nonmagnetic 63.5 0.842 29.5
Calculated Feed 100.0 1.81 100.0
No (heated none none Magnetic 0.37 12.9 2.7
to 135' C.) Nonmagnetic 99.63 1.71 97.3
Calculated Feed 100.0 1.75 100.0
What is claimed is:
1. In a process for the beneficiation of a sulfide ore
from gangue, excluding coal, wherein the ore is treated 15
with a metal containing compound under conditions
which cause the metal containing compound to react
substantially at the surface ofthe metal sulfide particles
to the substantial exclusion of the gangue particles so as
to alter the surface characteristics of the metal sulfide 20
values thereby causing a selective enhancement of the
magnetic susceptibility of one or more metal sulfide
values of the ore to the exclusion of the gangue iiI order
to permit a physical separation between the metal sulfide
values and the gangue, the improvement compris- 25
ing:
treating the ore with heat prior to its treatment with
the metal containing compound.
2. The process of claim 1 wherein the heat pretreatment
is conducted at a temperature of at least about 80· 30
Co
3. The process of claim 2 wherein the heat pretreatment
is conducted in the presence of a gas selected from
the group consisting of steaJ:Il, nitrogen, hydrogen, carbon
monoxide, carbon dioxide, ammonia, hydrogen 35
sulfide, sulfur dioxide, methane, air, ethane,· propane,
butane and other hydrocarbons in the gaseous state at
the pretreatment temperature.
4. Theprocess of claim 3 wherein the gas is employed
in an amount of at least about 2 cubic meters per hour 40
per metric ton of sulfide ore being treated.
5. The process of claim 3 wherein the gas is steam at
a temperature of at least 100· C. and employed in an
amount of from about 1 weight percent to about 50
weight percent water, based on the weight of the metal 45
sulfide ore.
6. The process of claim 2 or claim 3 wherein the
treatment of the ore with the metal containing compound
is conducted at a temperature within a range of
125· C. less than the general decomposition temperature 50
of the metal ccntaining compound in a specific system
for the ore being treated.
7. The process of claim 6 wherein the metal containing
compound is employed in an amount of from about
0.1 to 100 kilograms per metric ton of ore. 55
8. In a process for the beneficiation of a metal sulfidt::
ore from gangue, excluding coal, wherein the ore is
treated with from about 0.1 to about 100 kilograms of
metal containing compound per metric ton of ore at a
temperature within a range of 125· C. less than the 60
general 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 to about
4 hours to cause the metal containing compound to
react substantially at the surface of the metal sulfide 65
particles to the substantial exclusion ofthe gangue particles
so as to alter the surface characteristics of the metal
sulfide values thereby causing a selective enhancement
of the magnetic susceptibility of one or more. metal
sulfide values contained in the ore to the exclusion of
the gangue in order to permit a physical separation, the
improvement comprising:
the treatment of the· ore with heat prior to treating it
with the metal containing compound.
9. The process ofclaim 1 or claim 8 wherein the metal
containing compound is an iron containing compound.
10. The process of claim 9 wherein the iron containing
compound is selected from the group consisting of
ferrous chloride, ferric chloride, ferrocene, ferrocene
derivatives, ferric acetylacetonate, and ferricacetylacetonate
derivatives.
11. The process of claim 1 or claim 8 wherein the
metal containing compound is a carbonyl. .
12. The process. of claim 11 wherein the carbonyl is
selected from the group consisting of iron, cobalt, and
nickel.
i3. The. process of claim 12 wherein the carbonyl
comprises an iron carbonyl.
14.. The process of claim 9 .wherein the ore is pretreated
toa temperature of at least about 80· C. for a
time period of at least about0.1 hours.
15. The process of claim 14 wherein the ore. is pretreated
to a temperature of from about 125· C. to about
450· C. for a time period offrom about 0.20 t6 about 4
hours.
16. The process ofclaim 14 wherein the heat pretreatment
is conducted in the presence of a gas selected from
the group consisting of steam, nitrogen,hydrogen, carbon
monoxide, carbon dioxide, ammonia, hydrogen
sulfide, sulfur dioxide, methane, air, ethane, propane,
butane, and other hydrocarbon compounds in the gase~
ous state at the pretreatment temperature.
17. The process of claim 16 wherein the gas is employed
in an amount of at least about 12 cubic meters
per hour per metric ton of ore being processed.
18. The process of claim 16 wherein the gas is steam
at a temperature of from about 150·. C. to about 450' C.
and comprised of from about 5 weight percent to about
30 weight percent· water, based on the weight of the
metal sulfide ore.
19. The process of claim 17 wherein the gas is nitrogen.
20. The process of claim 17 wherein the gas is hydrogen.
21. The process of claim 17 wherein the gas is carbon
monoxide.
22. The process of claim 15 wherein the metal containingcompound
is an iron carbonyl and the treatment
of the ore with the iron carbonyl 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.
4,289,529
20
selected from the group consisting of steam, nitrogen,
hydrogen, and carbon monoxide.
44. The process of claim 43 wherein the ore is galena
and the gas is selected from the group consisting of
steam, nitrogen and hydrogen.
45. The process of claim 43 wherein the ore is sphalerite
and the gas is nitrogen.
46. In a process for the beneficiation of a sulfide ore
from gangue, excluding coal, wherein the ore is treated
with an iron carbonyl compound under conditions
which cause the iron carbonyl compound to react substantially
at the surface of the metal sulfide particles to
the substantial exclusion of the gangue particles so as to
alter the surface characteristics of the metal sulfide
15 values thereby causing a selective enhancement of the
magnetic susceptibility of one or more metal sulfide
values of the ore to the exclusion of the gangue in order
to permit a separation between the metal sulfide values
and the gangue, the improvement comprising:
treating the ore with heat prior to its treatment with
the iron carbonyl compound.
47. The process of claim 46 wherein the heat pretreatment
is conducted at a temperature of at least 800 C.
48. The process of claim 47 wherein the sulfide ore is
selected from the group consisting of galena, sphalerite,
molybdenite, stibnite, smaltite, chalcopyrite, orpiment,
cinnabar, bornite, arsenopyrite, realgar, pentlandite and
tetrahedrite.
49. The process of claim 47 or claim 48 wherein the
heat pretreatment is conducted in the presence of a gas
selected from the group consisting of steam, nitrogen,
hydrogen, carbon monoxide, carbon dioxide, ammonia,
hydrogen sulfide, sulfur dioxide, methane, air, ethane,
propane, butane, and other hydrocarbons in the gaseous
state at the pretreatment temperature.
50. The process of claim 49 wherein the pretreatment
is conducted at a temperature of from about 1750 C. to
about 2500 C.
51. The process of claim 49 wherein the gas is steam
at a temperature offrom about 1500 C. to about 4500 C.
and comprises from about 10 weight percent to about 25
weight percent water, based on the weight of the sulfide
ore being treated.
52. The process of claim 50 wherein the gas is hydrogen
employed in an amount of at least 120 cubic meters
per hour per metric ton of ore being treated.
53. The process of claim 50 wherein the gas is carbon
monoxide employed in an amount of at least about 120
cubic meters per hour per metric ton of ore being
treated.
54. The process of claim 50 wherein the gas is nitrogen
employed in an amount of at least about 120 cubic
meters per hour per metric ton of ore being treated.
55. The process of claim 50 wherein the iron carbonyl
is iron pentacarbonyl employed in an amount of from
about 2 to about 20 kilograms per metric ton of ore at a
temperature of 150 C. less than the general decomposition
temperature of the iron pentacarbonyl in a specific
system for the ore being treated for a time of from about
0.05 to about 4 hours.
56. The process of claim 11 wherein the ore is pretreated
to a temperature of at least about 800 C. fora
time period of at least about 0.1 hours.
57. The process of claim 56 wherein the ore is pretreated
to a temperature of from about 1250 C. to about
4500 C. for a time period of from about 0.20 to about 4
hours.
19
23. The process of claim 22 wherein the ore is treated
with heat and a gas selected from the group consisting
of steam, nitrogen, hydrogen, and carbon monoxide.
24. The process of claim 23 wherein the metal sulfide
ore is selected from the group consisting of galena, 5
sphalerite, molybdenite, stibnite, smaltite, chalcopyrite,
orpiment, cinnabar, bornite, arsenopyrite, realgar, pentlandite
and tetrahedrite.
25. The process of claim 24 wherein the ore is galena.
26. The process of claim 24 wherein the ore is molyb- 10
denite.
27. The process of claim 24 wherein the ore is stibnite.
28. The process of claim 24 wherein the ore is smaltite.
29. The process of claim 24 wherein the ore is chalcopyrite.
30. The process of claim 24 wherein the ore is orpiment.
31. The process of claim 24 wherein the ore is cinna- 20
bar.
32. The process of claim 24 wherein the ore is bornite.
33. The process of claim 24 wherein the ore is arsenopyrite.
34. The process of claim 24 wherein the ore is realgar. 25
35. The process of claim 24 wherein the ore is pentlandite.
36. The process of claim 24 wherein the ore is tetrahedrite.
37. The process of claim 23 wherein the gas is steam. 30
38. In a process for the beneficiation of a metal sulfide
ore from gangue, excluding coal, wherein the metal
sulfide ore is selected from a group consisting of galena,
molybdenite, sphalerite, bornite, cinnabar, arsenopyrite,
smaltite, chalcopyrite, orpiment, realgar, pentlandite, 35
stibnite, and tetrahedrite and wherein the ore is treated
with from about 2 to about 20 kilograms of an iron
containing compound per metric ton of ore at a temperature
within a range of 1250 C. less than the general
decomposition temperature of the iron containing com- 40
pound in a specific system for the ore being treated to
cause the iron containing compound to react substantially
at the surface of the metal sulfide particles to the
substantial exclusion of the gangue particles so as to
alter the surface characteristics of the metal sulfide 45
values thereby causing a selective enhancement of the
magnetic susceptibility of one or more metal sulfide
values contained in the ore to the exclusion of the
gangue in order to permit their magnetic separation, the
improvement for the ore in a specific system compris- 50
ing:
heating the ore to a temperature of at least about 800
C. prior to its treatment with the iron containing
compound.
39. The process of claim 38 wherein the iron contain- 55
ing compound is ferrocene and the heat pretreatment is
conducted in the presence of a gas selected from the
group consisting of steam, nitrogen, hydrogen, and
carbon monoxide.
40. The process of claim 39 wherein the ore is galena. 60
41. The process of claim 39 wherein the ore is sphalerite
and the gas is selected from the group consisting of
steam and nitrogen.
42. The process of claim 39 wherein the ore is molybdenite
and the gas is selected from the group consisting 65
of steam, hydrogen, and carbon monoxide.
43. The process of claim 38 wherein the iron containing
compound is ferric acetylacetonate and the gas is
• • • • •
4,289,529
21 22
58. The processorclaimS6 wherein the heat pretreat- 60. The process or claim 59 wherein the 'gas is steam
ment is conducted in the presence oh gaS selected from at a temperatureof from about ISO· C. to about 450· C.
. . '.'. and comprised of from about 5 weight percent to about
the group consisting ofsteam, nitrog~n, hydrogen, car- 30 weight percent water, based on the weightofthe
. boil monoxide, carbon dioxide, ammonia, hydrogen 5 metal sulfide ore.
sulfide, sulfur dioxide, methane, air, ethane, propane, 61. The process of claim 59 wherein the gas is nitrobutane
and other hydrocarbon compounds in the gase- gen.
.' ous state at the pretreatment. temperat\lre. 62. The process of claim 59 wherein the gas is hydrogen.
59. The process or claim 58 wherein the gas is em-· 10 . 63. The process of claim 59 wherein the gas is carbon'
plc;>yed in an amount orat least 12 cubic meters per hour .. monoxide; .
. per metric ton of ore being processed.
15
20
25
30
35
40
45
50
55
60
65