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US007824633B2
(12) United States Patent
Amelunxen et al.
(10) Patent No.:
(45) Date of Patent:
US 7,824,633 B2
Nov. 2, 2010
(Continued)
FOREIGN PATENT DOCUMENTS
W09612675
(54) SYSTEM AND METHOD FOR CONVERSION
OF MOLYBDENITE TO ONE OR MORE
MOLYBDENUM OXIDES
(75) Inventors: Peter Amelunxen, Arequipa (PE); John
C. Wilmot, Anthem, AZ (US); Chris
Easton, Highlands Ranch, CO (US);
Wayne W. Hazen, Lakewood, CO (US)
(73) Assignee: Freeport-McMoran Corporation,
Phoenix, AZ (US) WO
3,674,424 A
3,829,550 A
3,834,893 A
3,854,930 A
3,860,419 A
3,911,076 A
3,932,580 A
7/1972 Stanleyet al.
8/1974 Ronzio et aI.
9/1974 Queneau et al.
12/1974 Kentro
1/1975 Weber et aI.
10/1975 Probert et aI.
1/1976 Vertes et aI.
5/1996
(Continued)
OTHER PUBLICATIONS
A.G. Kholmogorov, et aI., "Ion exchange recovery and concentration
of rhenium from salt solutions", Hydrometallurgy 51 (1999( 19-35,
Elsevier Science B.Y.
(Continued)
Jul. 20, 2007
Subject to any disclaimer, the term ofthis
patent is extended or adjusted under 35
U.S.c. l54(b) by 0 days.
(21) Appl. No.: 11/780,850
(22) Filed:
( *) Notice:
Related U.S. Application Data
(60) Provisional application No. 60/866,763, filed on Nov.
21,2006.
(51) Int. Cl.
COlG 37/14 (2006.01)
(52) U.S. Cl. 423/58; 423/53; 423/54;
423/55; 423/593.1; 423/606
(58) Field of Classification Search 423/58,
423/53,54,55,593.1,606
See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
Prior Publication Data Primary Examiner-Melvin C Mayes
Assistant Examiner-Melissa Stalder
(74) Attorney, Agent, or Firm-Snell & Wilmer L.L.P.
A system and method for producing molybdenum oxide(s)
from molybdenum sulfide are disclosed. The system includes
a pressure leach vessel, a solid-liquid separation stage
coupled to the pressure leach vessel, a solvent-extraction
stage coupled to the solid-liquid separation stage, and a base
stripping stage coupled to the solvent-extraction stage. The
method includes providing a molybdenum sulfide feed, subjecting
the feed to a pressure leach process, subjecting pressure
leach process discharge to a solid-liquid separation process
to produce a discharge liquid stream and a discharge
solids stream, and subjecting the discharge liquid stream to a
solvent extraction and a base strip process.
(57) ABSTRACT
US 2008/0118422 Al May 22,2008
(65)
1,923,652 A
3,117,860 A
8/1933 Winkler et al.
1/1964 Bjerkerud et al. 14 Claims, 3 Drawing Sheets
US 7,824,633 B2
Page 2
u.s. PATENT DOCUMENTS 4,601,890 A 7/1986 Cheresnowsky
4,604,266 A 8/1986 Cheresnowsky et al.
3,941,867 A 3/1976 Wilkomirsky et al. 4,604,267 A 8/1986 Cheresnowsky
3,988,418 A 10/1976 Kerfoot et al. 4,861,565 A * 8/1989 Sefton et al. .................. 423/55
4,000,244 A 12/1976 Mollerstedt et al. 5,804,151 A * 9/1998 Sweetser et aI. .............. 423/58
4,006,212 A 2/1977 Alper et al. 5,820,844 A 10/1998 Khan et aI.
4,046,852 A * 9/1977 Vertes et al. .................. 423/58 6,149,883 A 11/2000 Ketcham et al.
4,079,116 A 3/1978 Ronzio et al. 6,730,279 B2 5/2004 Balliett et aI.
4,083,921 A 4/1978 Wesely 7,169,371 B2 1/2007 Jones
4,138,248 A 2/1979 Narain 2005/0019247 Al * 1/2005 Balliett et aI. ............ 423/592.1
4,165,362 A 8/1979 Reynolds 2008/0124269 Al 5/2008 Daudey et aI.
4,207,296 A 6/1980 Nauta et al. 2008/0166280 Al 7/2008 Daudey et aI.
4,236,918 A 12/1980 Narain
4,273,745 A 6/1981 Laferty et aI. FOREIGN PATENT DOCUMENTS
4,296,077 A 10/1981 Heuer et al. WO W09966085 12/1999
4,379,127 A 4/1983 Bauer et al. WO W02008061231 5/2008
4,444,733 A 4/1984 Laferty et aI.
4,478,698 A 10/1984 Wilkomirsky et al. OTHER PUBLICATIONS
4,500,496 A 2/1985 Austin et al.
Notification ofTransmittal ofthe International Search Report and the
4,525,331 A 6/1985 Cheresnowsky et al.
Written Opinion of the International Searching Authority, or the
4,551,312 A 11/1985 Yuill Declaration in PCTIUS2007/084496 issued Jul. 29, 2008.
4,555,386 A 11/1985 Cheresnowsky
4,596,701 A 6/1986 Cheresnowsky et al. * cited by examiner
u.s. Patent Nov. 2, 2010 Sheet 1 of 3 US 7,824,633 B2
10
/
96
30
UPGRADE 19
---. 28 24 25 21
---. 32 23
~~20
22
34
53 ~~ 52
38 40 rr 44 ·......···0
S/L SEPARAT!ON
68 88 48
82 -fS:R~~~~G I
""' 76
86
84
FIG. 1
u.s. Patent Nov. 2, 2010 Sheet 2 of 3
200
/
US 7,824,633 B2
PROVIDE MoS2
.....-202
t
DEOIL ~204
UPGRADE ..,,-206
n
REPULP
REPULP /208
WATER
~
,
PRESSURE
,./ /210 .. LEACH
Mo03
WASH SOLID/LIQUID
WATER SEPARATION _212
I+
ORGANIC EXTRACTION ,/""214
~
~
BASIC SOLUTION.. /216 STRIP
... I+
(OPTIONAL) ~218 .... CATION EXCHANGE
FIG. 2
u.s. Patent Nov. 2, 2010 Sheet 3 of 3 US 7,824,633 B2
100
/
SUPPLY ......- 98
112
102
134
140
124
128
-94
106 . / /104 po LEACH SOLUTION DISSOLVER TANK V SUPPLY
/118
-110 '. DOWNGRADE /116 FILTRATION
CIRCUIT ... SYSTEM V
f.--120 -114
d,
LOW-GRADE ADJUSTMENT V ~108 OXIDE ~122 TANK SYSTEM
+126
CRYSTALLIZER
SYSTEM V
.1, --132
SEPARATION .....- SYSTEM
~138
llr
DRYING V STAGE
FIG. 3
US 7,824,633 B2
1
SYSTEM AND METHOD FOR CONVERSION
OF MOLYBDENITE TO ONE OR MORE
MOLYBDENUM OXIDES
2
within the vessel. As a result, Mo03 is generated in accordance
with one or more variations of the following exothermic
reaction.
SUMMARY OF THE INVENTION
MOS2+4.502(g)+2H20~Mo03+2H2S04
The present invention provides a method and a system for
converting molybdenite (MoS2 ) to one or more molybdenum
oxides. While the ways in which the present invention
addresses the various drawbacks of the prior art will be discussed
in greater detail below, in general, the invention provides
a system and method for recovering a high yield of
molybdenum oxide using a relatively non-corrosive stripping
process.
In accordance with various embodiments ofthe invention,
a method for converting molybdenite to molybdenum oxides
Several patents and other literature have taught numerous
processes and systems for carrying out one or more variations
on the above reaction to greater or lesser degrees of completion.
Some of the patents which discuss this type of process
10 include: U.S. Pat. No. 4,046,852 to Vertes, et aI., entitled
"Purification Process for Technical Grade Molybdenum
Oxide"; U.S. Pat. No. 4,165,362 to Reynolds, entitled
"Hydrometallurgical Processing of Molybdenite Ore Concentrates";
U.S. Pat. No. 4,379,127 to Bauer, et aI., entitled
15 "Method of Recovering Molybdenum Oxide"; U.S. Pat. No.
4,444,733 to Laferty, et aI., entitled "Process for Recovering
Molybdenum and Copper From Sulfide Concentrates"; U.S.
Pat. No. 4,478,698 to Wilkomirsky, et aI., entitled "Process
For Recovering Copper and Molybdenum From Low Grade
20 Copper Concentrates"; U.S. Pat. No. 4,512,958 to Bauer, et
aI., entitled "Method of Recovering Molybdenum Oxide";
U.S. Pat. No. 5,804,151 to Sweetser, et aI., entitled "Process
For Autoclaving Molybdenum Disulfide"; and U.S. Pat. No.
5,820,844 to Khan, et aI., entitled "Method for the Production
25 ofA Purified Mo03 Composition."
Many ofthese patents and other publications focus on the
oxidation reaction that converts some or all of the MoS2 to
Mo03 or other molybdenum oxides, which other oxides may
be referred to as lesser molybdenum oxides. While the oxi-
30 dation reaction is an important step in the preparation of
molybdenum oxide from molybdenum-containing ore, the
process for obtaining usable molybdenum typically includes
numerous post-oxidation reaction steps that are important to
the overall efficiency of the process.
U.S. Pat. No. 6,730,279, to Balliett et aI., entitled "Production
ofPure Molybdenum Oxide from Low Grade Molybdenite
Concentrates," which issued on May 4, 2004, illustrates
possible post-oxidation steps. For example, a process illustrated
in Balliett et al. includes an oxidation step, followed by
40 a separation step to separate the molybdenum oxide material
from a centrate. The centrate is sent to an optional amine
solvent-extraction process operated to produce a two-phase
mixture having a molybdenum-loaded organic phase and an
aqueous phase. The organic phase is stripped with concen-
45 trated sulfuric acid, at a pH less than about 3 and the recovered
molybdenum values are recycled back to the oxidation step.
Although the inventors purport that this process works, some
results indicate otherwise. Furthermore, use of concentrated
sulfuric acid to strip the organic material is detrimental to
50 most processing equipment and thus increases operating
costs of molybdenum recovery systems and processes.
Accordingly, improved methods and systems for efficiently
obtaining molybdenum oxide from molybdenite concentrates
that do not employ sulfuric acid stripping are desired.
FIELD OF INVENTION
CROSS REFERENCE TO RELATED
APPLICATIONS
BACKGROUND OF THE INVENTION
The present invention generally relates to the processing of
molybdenum and more particularly to the production of
molybdenum oxide materials (e.g., molybdenum trioxide,
Mo03 ) from molybdenum sulfide (e.g., MoS2 ).
Molybdenum is an increasingly important material and is
used for various industrial and scientific purposes. These
purposes range from imparting strength in metal alloys to use
as a chemical catalyst. Likewise, molybdenum compositions
are highly suitable for the production of a wide variety of
products, including electrical contacts, electrical filaments,
colloidal lubricant additives, and other diverse products.
Molybdenum does not occur as a free element in nature. In
nature it can be found in various common forms, such as in
ore in the form of molybdenite (MoS2 ). Molybdenite generally
forms a relatively small percentage of the ore in which it
is found. Typically, molybdenite ore consists of silicified
granite compositions having deposits of soft, black, and hex- 35
agonal MoS2 crystalline structures widely dispersed therein.
These materials are found in an average concentration ofonly
about less than 1% by weight of the entire ore body. Accordingly,
significant process steps are typically required in order
to recover molybdenum from ore.
In view of its increasing industrial and scientific importance,
substantial research activity has been devoted to the
development of improved methods for the beneficiation of
MOS2 -containing ore products. Normally, MoS2 derived
from molybdenite ore is converted by oxidization to various
oxides of molybdenum, followed by further processing in
order to obtain a purified molybdenum oxide product consisting
primarily ofmolybdenum trioxide (Mo03 ).
The molybdenite ore may be initially subjected to a physical
grinding process in which the ore is reduced in size to a
plurality of small particles. The ore particles are then further
treated to remove the desired MoS2 . This step may be accomplished
using a variety of techniques, including organic flotation
extraction procedures. As a result, the desired MoS2
may be effectively separated from ore-based waste materials 55
(conventionally known as "gangue") which consist primarily
of silica-containing by-products. Specifically, the desired
MoS2 compositions will, by control of the surface chemistry
within the flotation unit, be readily isolated in the flotation
froth. Many variations and alternatives exist in connection 60
with the isolation of MoS2 from the ore, with the selected
procedure depending on the type and grade of ore to be
processed.
Once isolated, MoS2 may converted (oxidized) to form
Mo03 by forming a slurry or suspensionofMoS2 in water and 65
thereafter heating the slurry in a pressure leach vessel. During
the heating process, an oxygen atmosphere is maintained
This application claims the benefit of provisional application
Ser. No. 60/866,763, entitled SYSTEMAND METHOD
FOR CONVERSION OF MOLYBDENITE TO ONE OR
MORE MOLYBDENUM OXIDES, filed Nov. 21, 2006.
US 7,824,633 B2
3 4
DETAILED DESCRIPTION
BRIEF DESCRIPTION OF THE DRAWING
FIGURES
FIG. 1 illustrates a system for converting MoS2 concentrate
to molybdenum oxide;
FIG. 2 illustrates a process for converting MoS2 concentrate
to molybdenum oxide; and
FIG. 3 illustrates a schematic block flow-chart of a system
for additional processing of molybdenum oxide.
The present disclosure refers to and describes a method, a
processing system, and accompanying components and
equipment. A substantial portion of the disclosure herein is
directed to a system for and a method of processing molybdenite
concentrates to produce molybdenum oxide and other
compositions. It should be appreciated that the broader process
steps described herein may be accomplished by a variety
of equipment configurations and sub-process steps, each of
which are within the scope of the present invention. For
example, the following disclosure describes filter systems on
a number of occasions. Particular equipment is generally
described as being suitable for particular filter systems. However,
other equipment may be implemented or combined with
other equipment to accomplish the function ofa filter system
described herein. Additionally or alternatively, the present
system and method may be implemented or adapted to process
other starting materials and/or to produce different final
products.
With reference to FIG. 1 and FIG. 2, a system 10 and a
process 200 to generate molybdenum oxide product (Mo03 )
from MoS2 starting materials are respectfully illustrated. The
system components and process steps are illustrated in block
diagram format to re-emphasize that the present invention is
not limited to any specific hardware or processing equipment,
with many different types of operating components being
suitable for use in the disclosed system and process.
As illustrated in FIG. 1 and FIG. 2, process 200 initially
involves a step 202 of providing a supply of molybdenum
sulfide (MoS2 ), designated as reference number 12 in FIG. 1.
Many of the initial steps in process 200, such as obtaining a
processed for final upgrading of rhenium and molybdenum.
The SX circuit may also produce a copper bearing acid solution,
which may be further processed for reclamation or recycling
of the acid and the copper.
In continuing discussion of some exemplary configurations
of the solid-liquid separation stage, the solids residue
from the solid-liquid separation stage (e.g., the last thickener
thereof) is filtered using a filtration unit. The filtration unit
may include a rotating drum, belt, pressure filter, or other
10 conventional filter. The filtrate is returned to the solid-liquid
separation stage, to the solution extraction stage, and/or fed to
the pressure leach vessel feed stream. The filter cake from the
filtration step includes oxide product, which may be utilized
or sent to further processing.
As one example of additional processing of the oxide, the
wet filter cake from the filtration step described above may be
further processed to produce one or more of commercial
products or chemical product precursors, such as, for
example, an anlillonium dimolybdate (ADM) product.
Many features ofthe present disclosure will become manifest
upon making reference to the detailed description which
follows and the accompanying sheets of drawings in which
preferred embodiments incorporating the principles of this
disclosure are provided as illustrative examples only.
20
includes optionally deoiling the molybdenite concentrate,
optionally metallurgically upgrading the concentrate, pressure
leaching a slurry ofmolybdenite concentrate, separating
the pressure leach discharge solids from the pressure leach
discharge liquid, optionally washing the resultant discharge
solids, extracting soluble molybdenum and optionally other
materials from a resultant filtrate using organic anionic solvent
extraction techniques and/or ion exchange techniques,
stripping the loaded organic material with a basic solution
(e.g., an alkali metal base solution, such as a solution including
an alkali metal hydroxide, alkali metal carbonate or bicarbonate,
or an alkaline earth metal base solution, such as a
solution including an alkaline earth metal carbonate or bicarbonate)
recycling the strip solution or a portion thereof to the
pressure leach operation, feed slurry tank, and/or a quench 15
solution system, optionally extracting sodium from the
recycle strip solution with a strong cationic ion-exchange
resin prior to recycling the molybdenum solution to the pressure
leach system, and removing a small stream of concentrated
strip solution to recover other materials.
In accordance with additional embodiments of the invention,
a system for converting molybdenite to molybdenum
oxides includes (optionally) a deoiler, (optionally) a metallurgical
upgrade stage, a pressure leach vessel, a solid-liquid
separation stage or stages, a solvent-extraction stage and/or a 25
an ion exchange stage, a stripping stage, and optionally a
cation-exchange stage.
In accordance with various aspects of the exemplary
embodiments, molybdenum oxide is recovered from molybdenum
sulfide by initially providing filtered, dried, and 30
optionally deoiled and/or upgraded MoS2 , which may be fed
directly from a prior concentration/isolation process step,
repulped after such process steps, and/or provided from some
other source of MoS2 concentrate. The MoS2 concentrate is
fed into a pressure leach vessel operating at, e.g., about 2250 35
C. and about 450 psi and about 100 oxygen psi overpressure.
The MoS2 concentrate may be fed to the pressure leach vessel
continuously. An oxygenated environment may be maintained
in the pressure leach vessel through any suitable
method, such as sparging oxygen into the pulp zone at about 40
100 psi overpressure. Additionally, quench water and/or or
coolant may be added to the vessel to maintain temperature
and pressure. The pressure leach vessel may also receive a
recycle stream including at least a portion of a liquid stream
from a solid-liquid separation stage. In some implementa- 45
tions, the recycle stream from the solid-liquid separation
stage overflow may improve the oxidation kinetics in the
vessel and thus improve the overall recovery percentage of
molybdenum from the molybdenum sulfide.
The discharge from the pressure leach vessel may be 50
depressurized in a flash tank before proceeding to the solidliquid
separation stage. In some configurations of the solidliquid
separation stage, at least 2 thickeners are operated in
counter-current mode.A portion ofthe solid-liquid separation
stage leach liquor from, e.g., a first thickener may report to a 55
solution extraction (SX) and/or an ion exchange circuit while
another portion of the leach liquor may be recirculated or
recycled back to the feed stream ofthe pressure leach vessel.
The solid-liquid separation stage liquid fraction stream proceeding
to the solution extraction circuit may be filtered in 60
one or more filtration stages before proceeding to the SX
circuit. In the SX circuit, solubilized materials, such as Mo
and Re values are removed from the solid-liquid separation
stage liquid fraction stream via an organic stage. The loaded
organic is then washed and materials (e.g., the Mo and Re 65
values) are stripped with a basic solution. The aqueous solution
including the, e. g., Mo and Re, values may then be further
5
US 7,824,633 B2
6
molybdenum sulfide supply 12, are somewhat conventional
and taught by numerous patents, including u.s. Pat. No.
5,804,151, which shares common ownership with the present
application. For the purposes of completeness, a brief
description ofthese initial steps is provided herein in substantially
the same fonn as provided in u.s. Pat. No. 5,804,151,
which is incorporated herein by reference in its entirety for all
purposes.
To obtain initial MoS2 starting material 12, molybdenum
sulfide is derived from a supply of molybdenite (MoS2 -con- 10
taining) ore (not shown), which is available from numerous
mine sites throughout the world. For example, a representative
mine site from which large supplies of molybdenite ore
may be obtained is the Henderson mine at Empire, Colo.
(USA). This mine site is generally characterized as a "pri- 15
mary" mine which is capable of producing large amounts of
relatively pure product. However, of increasing interest is
"by-product" molybdenite, which involves a secondary product
combined with copper-containing materials obtained
from "nonprimary" mine sites (e.g., the Sierrita Mine at Tuc- 20
son, Ariz. (USA) and others). System 10 and process 200 are
capable of effectively processing both "primary" and "secondary"
ore materials and should not be regarded as limited to
anyone type.
Once obtained, the molybdenite ore may be thereafter pro- 25
cessed in a conventional marmerto separate the desired MoS2
from the surrounding waste material which is nonnally comprised
of silicified granite and is commonly referred to as
"gangue." A basic procedure for isolating the MoS2 from
other components ofthe molybdenite ore is described in U.S. 30
Pat. No. 4,046,852 to Vertes et a!., which is hereby incorporated
by reference for all that it discloses. Essentially, the
molybdenite ore, which may contain only about less than 1%
by weight MoS2 in the fonn of black, hexagonal crystals, is
first subjected to a size reduction stage using a conventional 35
size reduction (e.g., grinding and crushing) apparatus known
in the mining industry for this purpose. A representative size
reduction apparatus suitable for use with the system and
process of the invention includes a standard impact milling
system or roll crusher unit. However, other grinding and 40
crushing systems may also be used, with the present invention
not being exclusively restricted to any particular type of size
reduction apparatus.
As a result of the grinding and crushing step described
above, the molybdenite ore is converted into a ground ore 45
product which is typically in particulate fonn having an average
particle size ofabout 50 to about 300 micrometers. Thereafter,
the ground ore product may be treated in many different
ways to separate the desired MoS2 therefrom. For example,
the ground ore product may be introduced into a conventional 50
flotation extraction system which employs numerous
reagents including various hydrocarbon compositions, as
well as selected wetting agents. Flotation extraction systems
are known in the mining industry, with specific infonnation
involving a representative flotation-based extraction system 55
for processing molybdenite ore being described in U.S. Pat.
No. 4,046,852, discussed above, and U.S. Pat. No. 3,834,894
to Spedden, et a!., which is also incorporated herein by reference
for all that it discloses. A wide variety of different
flotation chemicals may be used in connection with conven- 60
tional flotation systems ofthe type described above including,
but not limited to, butyl carbitol, allyl esters, and potassium
xanthates. Typically, the "float" product associated with a
representative flotation extraction system will contain the
desired isolated molybdenum sulfide that can be used as 65
starting material 12. The "sink" product is primarily of the
waste gangue, which may be discarded or further processed if
desired. Ofcourse, it is commonthat such flotation extraction
processes often utilize multiple, sequential flotation stages
and may include intervening grinding steps, depending on the
particular type of ore being processed and other extrinsic
considerations. Consequently, the present invention should
not be regarded as limited to any particular flotation extraction
procedures or other processes for obtaining molybdenum
sulfide 12, with many other conventional techniques being
applicable as discussed above.
At this stage, initial supply of molybdenum sulfide 12 is
ready for further processing, and will typically have a particle
size of about 10 to about 100 micrometers. Initial supply of
molybdenum sulfide 12 will likely have a number of residual
compositions associated therewith, which originated within
the ore product. Specifically, these materials are carried over
into initial supply ofmolybdenum sulfide 12 from the ground
ore product, with initial supply of molybdenum sulfide 12
normally containing about 0.2-35% by weight non-MoS2
materials. These non-MoS2 materials will typically include
small amounts ofresidual gangue as well as various ganguederived
metals and metal compounds (e.g., metal oxides,
chlorides, sulfides, and the like) which include, but are not
limited to, the following metals: potassium, manganese,
sodium, lead, tin, magnesium, calcium, iron, copper, bismuth,
and aluminum. The exact amount and concentration of
these materials within molybdenum sulfide starting material
12 (with such materials collectively being referred to herein
as "contaminants") will, of course, vary depending on the
particular ore body from which the initial ore was obtained, as
well as the level and/or type ofpreliminary treatment used to
produce molybdenum sulfide starting material 12. As discussed
further below, these naturally-derived contaminants
may be removed at some point during the molybdenum purification
process in order to prevent undesired contamination
of the final molybdenum products (e.g., products generated
from molybdenum trioxide (Mo03 ) produced in accordance
with process 200 described herein).
Depending on the level and type ofcontaminants present in
molybdenum sulfide supply 12 and the filtration steps desired
after the oxidation ofthe MoS2 in a pressure leach vessel 20,
MoS2 supply 12 may be subjected to one or more additional
purification steps prior to entering pressure leach vessel 20.
For example, initial molybdenum sulfide supply 12 may by
subjected to an optional deoiling step 204 and system 10 may
include optional deoiling apparatus 14. Deoiling can be used
to strip hydrocarbon material from the feed to produce an
upgraded feed 16, which increases the effective kinetics of a
pressure leach step 210, described in more detail below. Thus,
incorporation of a deoiling stage facilitates maintenance of
equipment of system 10 by reducing an amount ofhydrocarbon
material that is exposed to the equipment and increases
efficiency of process 200.
Deoiling step 204 may be perfonned using either thennal
or solvent deoiling techniques and apparatus. An exemplary
thennal deoiling process includes, e.g., exposing the feed to
an indirect fired rotary kiln. Exemplary solvent deoiling processes
include exposing the feed to an acetone or other solvent
wash stage(s).
The feed may also be exposed to an optional hydrometallurgical
upgrade apparatus 19 (step 206). Optional hydrometallurgical
upgrade step 206 may include various purification
sub-steps that may be implemented prior to the pressure leach
vessel and may include one or more sub-steps and apparatus
19 may include one or more hardware components to accomplish
the step(s). Optional upgrade step 206 may involve
leaching of molybdenum sulfide supply 12 with a selected
reagent or reagents (e.g., HCl) to "upgrade" supply 12 or 16
US 7,824,633 B2
7 8
the molybdenum sulfide particles and also to effect an
entrainment ofminute bubbles containing free oxygen (02 ) to
effect oxygen mass transfer to the aqueous slurry. The agitation
ofleach slurry 22 also promotes a mechanical scrubbing
ofthe particle surfaces for removing any film ofmolybdenum
oxide formed thereon, thereby exposing fresh molybdenum
sulfide for further reaction with free oxygen.
As introduced above, the provision of free oxygen into
pressure leach vessel 20 may be accomplished in any suitable
10 manner. As one example, oxygen-containing gas 24 may be
delivered from oxygen-containing gas supply 26. Exemplary
oxygen-containing gases include pure oxygen gas, air/oxygen
mixtures, and air, such as naturally occurring air. Oxygen-
containing gas 24 may be sparged into pressure leach
15 vessel 20 directly into leach slurry 22. Additionally or alternatively,
oxygen-containing gas 24 may be fed to pressure
leach vessel 20 into a gaseous portion of the pressure leach
vessel and allowed to mix with leach slurry 22 through the
action ofthe mechanical agitators. Sparging oxygen-contain-
20 ing gas 24 into leach slurry 22 may be preferred due to the
additional mixing and agitation effected thereby. Other suitable
methods of introducing oxygen into pressure leach vessel20
may alternatively be implemented. Oxygen-containing
gas 24 may be provided at any suitable pressure, such as a
25 pressure greater than the pressure in pressure leach vessel 20.
In some implementations, oxygen-containing gas 24 may be
sparged into leach slurry 22 at about 100 psi overpressure.
FIG. 1 also illustrates that water 28 may be delivered to
pressure leach vessel 20 from a suitable supply 30. Water 28
30 is an example of an acceptable coolant 32 that may be added
to pressure leach vessel 20 to maintain the oxidation reaction
at a desired temperature and/or pressure. Other suitable coolants
may be used as well, including coolants that include
water mixed with other components that may be selected to
35 provide additional cooling and/or pressure control effects.
Water may be a suitable coolant due to its role in the oxidation
reaction that converts MoS2 to Mo03 . Coolant stream 32 may
be delivered from fresh supply 30 as illustrated and, additionally
or alternatively, may be delivered in whole or in part from
40 recycle streams originating in other parts of the process,
whether upstream or downstream.
A discharge 34 from pressure leach vessel 20 may be
depressurized in a flash tank 36 before proceeding as a leach
45 product stream 38 to a solid-liquid separation stage 40 (step
212). Stage 40 may comprise various apparatus, such as
equipment suitable for counter-current decantation, thickening,
filtration, and centrifugation.
As indicated above, slurry 22 in the pressure leach vessel
50 20 may be at pressures greater than about 400 psi and at
temperatures greater than about 2000 C. (e.g., about 2000 C.
to about 2500 c., preferably about 2150 C. to about 2350 C.).
Depending on the configuration ofthe solid-liquid separation
stage 40, it may be desirable to reduce the temperature and/or
55 pressure ofleach product stream 38 prior to entering stage 40.
Flash tank 36 is one example of equipment that may be used
to accomplish such temperature and/or pressure reductions;
other equipment or combinations of components may be
similarly implemented.
In accordance with one embodiment ofthe invention, stage
40 is a counter-current decantation circuit. Suitable conntercurrent
decantation circuits include at least 2 thickeners operated
in counter-current mode. The general principles of
counter-current decantation are well-known and will not be
65 fully explicated herein. It is sufficient herein to snnnnarize
such circuits as including any number ofthickeners, generally
operated in series and in counter-current mode.
to material 21, i.e., preliminarily remove, various contaminant
materials from the molybdenum sulfide, such as extraneous
lead. A representative hydrometallurgical upgrade step
206 may include the step of combining initial supply of
molybdenum sulfide 12 or 16 with the selected reagent (e.g.,
HCl) in a vessel to form a slurry. The vessel may be provided
with a stirrer to ensure a thorough dispersal ofthe solids in the
slurry. The slurry may then be filtered by a suitable filter to
produce upgraded molybdenum sulfide-containing feed
material 21 and a filtrate 18 containing contaminants (e.g.,
lead) solublized by the reagent. Filtrate 18 may then be disposed
ofor treated in any suitable manner. Again, it should be
emphasized that hydrometallurgical upgrade step 206 is
optional.
Although process 200 is illustrated with optional deoiling
step 204 followed by optional hydrometallurgical upgrade
step 206, when a process includes both steps 204, 206, the
steps may be performed in any order. After either step, feed
material 21 is optionally repulped with a liquid 25 (step 208)
to form a feed material 23, which is fed to pressure leach
vessel 20.
As noted above, steps 204, 206, and 208 are optional, and
thus feed material 23, 21, 19, and starting material 12 may be
the same or altered by the optional processing steps and
apparatus as described above. In any event, MoS2 -containing
feed material (e.g., feed 23) is fed to pressure leach vessel 20,
whether directly from the MoS2 supply 12 or from the
optional upgrade steps 204, 206. Feed material 23 may comprise
an aqueous slurry comprising water and MoS2 . Feed
material 23 may assay at about 36-40% S, but may vary
depending on the purity of the initial supply ofmolybdenum
sulfide, the amount of contaminants, and treatment prior to
entry ofvessel 20. For example, it has been found that exposing
feed material 12 to a deoiling process reduces an amount
of total sulfur. Additionally or alternatively, the MOS2-containing
feed material 23 may be provided in other suitable
forms depending on the preceding process steps. For
example, MOS2 -containing feed material 23 may comprise a
filter cake having less water than a slurry. As noted below,
other streams may be fed to pressure leach vessel 20 to provide
a suitable leach slurry 22 during an oxidation step in the
pressure leach vessel (step 210).
By way of particular example, leach slurry 22 includes
sulfuric acid to facilitate the oxidation reaction. And, in accordance
with various aspects of the invention, a desired acid
concentration is maintained by recirculating an acid discharge
stream from step 212, as described below.
Pressure leach vessel 20 may be operated in either a batch
mode or a continuous mode. Pressure leach vessel 20 may
include a heater and one or more mixing motors having corresponding
blades or agitators. Pressure leach vessel 20 may
also include one or more sparger-type agitators through
which a free oxygen-containing gas 24 from a supply 26 is
admitted under pressure into pressure leach vessel 20 in the
form of a stream of bubbles. Since mechanical and spargertype
agitators are well-known, the particular mechanical and
sparger-type agitators utilized in one preferred embodiment
of the pressure leach vessel 20 are not described in further
detail. Pressure leach vessel 20 may include additional or
alternative components configured to facilitate effective mix- 60
ing of the materials in leach slurry 22 within vessel 20,
together with the proper temperatures and pressures for the
desired oxidation reaction.
As one example ofa suitable combination ofequipment for
pressure leach vessel 20, the combination of mechanical and
sparger-type agitators has been found to provide a satisfactory
degree of agitation to effect the continued dispersion of
US 7,824,633 B2
9 10
implementations of the optional filtration stages, the filtrate
will continue to SX circuit 50 as SX feed stream 54' with a
filter cake 58 being directed to additional process steps, to
disposal, or to other uses depending on the composition ofthe
filter cake. As can be understood from the foregoing discussion,
a variety of filters and other equipment may be implemented
as optional filtration stages 56. As filtration equipment
and its operation is well understood, additional
description ofthe various configurations will not be provided
herein in the interest of brevity and clarity.
In accordance with one embodiment ofthe invention, in SX
circuit 50, solubilized Mo and Re values are removed from
SX feed stream 54 or 54', filter or unfiltered, via traditional
solution extraction principles (step 214). Here again, general
solution extraction techniques are well known and will not be
described in detail; however, specific implementations and
sub-steps in utilizing solution extraction at this point in the
process to accomplish the results and functions described
herein are believed to be not well known. Accordingly, com-
20 ponents ofSX circuit 50 are described along with at least one
example of a method of using solution extraction to accomplish
the desired extraction.
With continuing reference to FIG. 1, SX circuit 50 may be
implemented and adapted to extract Mo values and/or Re
values from an aqueous stage into an organic stage. Additionally,
SX circuit 50 may be adapted to leave copper values
and/or other metal values in an acidic aqueous stage. As one
example ofa suitable solution extraction implementation, SX
circuit 50 may utilize Alamine® 336, a tertiary amine having
the chemical name oftricaprylyl amine, as the organic stage
into which the Mo values and/or Re values are extracted. As
shown in FIG. 1, an organic feed 60 to SX circuit 50 may be
delivered from an organic supply source 62. Additionally or
alternatively, organic feed 60 may be delivered from other
sources within the facility, such as via a recycle stream from
other process steps, such as shown in FIG. 1 as an optional
recycle stream 64. Alamine® 336 is one example ofa suitable
organic feed 60; other suitable organics may be similarly
utilized in accordance with this illustrative embodiment, pro-
40 vided they are selected to extract at least one ofthe Mo and Re
values from the aqueous stage. As introduced above, solution
extraction circuit 50 may be adapted to leave certain metal
values in an aqueous stream 66. As illustrated in FIG. 1,
aqueous stream 66 may exit SX circuit 50 and proceed to
additional processing apparatus 68 to recover those metal
values. As one example, some implementations ofthe present
invention may produce aqueous stage 66 including copper
values in an acidic aqueous solution. In such circumstances,
aqueous stream 66 may be directed to additional processing
50 facilities 68, such as additional leaching or solution extraction
equipment and processes to recover and/or recycle copper
and/or acid, each ofwhich may have commercial or methodological
advantages to implementers ofthe present invention.
Continuing with the discussion of the outputs from SX
circuit 50, an organic stream loaded with, for example, Mo
values and/or Re values may be washed under appropriate
circumstances following an initial extraction step. A washed
organic stage 70 may be directed to a stripping stage 72,
where the loaded organic is stripped with basic solution (e.g.,
an alkali metal base solution, such as a solution including an
alkali metal (e.g., sodium) hydroxide, alkali metal (e.g.,
sodium or potassium) carbonate or bicarbonate, or an alkaline
earth metal base solution, such as a solution including an
alkaline earth metal (e.g., calcium) carbonate or bicarbonate)
74 to strip the Mo and/or Re values into the basic solution
(step 216). By way of one example, a NaOH solution (about
15% NaOH in aqueous solution) is used as agent 76 for
End product streams, or outputs, from stage 40 generally
include an overflow liquids fraction 46 (e.g., from a first
thickener 42) and a underflow solids product 48 (e.g., from
the last thickener 44 in the series), consisting principally of
solids. In the context of the present disclosure, stage 40 is
implemented to accomplish solid/liquid separation of leach
product stream 38. Depending on the condition ofleach product
stream 38 and other design and implementation options in
the present method and system, a CCD circuit may include
greater or fewer thickeners as needed to accomplished the 10
desired separation at this stage of the process.
As illustrated in FIG. 1, a portion of liquids fraction 46
from stage 40 may be directed to a solution extraction (SX)
circuit 50 while another portion of solid-liquid separation
stage liquids fraction 46 may be recirculated or recycled back 15
to pressure leach vessel 20. For purposes of clarity, the portion
recycled to pressure leach vessel 20 is referred to herein
as a leach recycle stream 52, while the portion directed to
solution extraction circuit 50 is referred to herein as an SX
feed stream 54.
Relative amounts of liquids fraction 46 that become feed
stream 54 and leach recycle stream 52 may vary according to
the overall design ofthe equipment providing the functions of
the present invention. Additionally or alternatively, the composition
and/or flow rate of leach recycle stream 52 may be 25
adjusted based on the reaction conditions of pressure leach
vessel 20, such as to assist in creating the optimal reaction
conditions. In some implementations ofthe present invention,
leach recycle stream 52 from overflow 46 may be adapted to
improve the reaction kinetics in pressure leach vessel 20. For 30
example, leach recycle stream 52 may improve the reaction
kinetics by assisting in maintaining a desired temperature,
acid concentration, and/or pressure. Additionally or alternatively,
leach recycle stream 52 may improve the reaction
kinetics by providing seed material to accelerate the produc- 35
tion ofprecipitates from leach slurry 22. Leachrecycle stream
52 may provide a variety of other benefits to the overall
methods of the present disclosure. A portion of overflow 46
may additionally or alternatively be fed to feed stream 23
(prior to entering pressure leach vessel 20).
As illustrated in FIG. 1, system 10 may optionally include
an ion exchange stage 53. Stage 53 is generally designed to
remove metals such as rhenium. In the illustrated embodiment,
ion exchange stage 53 is interposed between solidliquid
separation stage 40 and pressure-leach vessel 20, in a 45
recycle loop. However, stage 53 may additionally and/or
alternatively be located elsewhere to capture metal values
from solid-liquid stage 40. By way of one example, stage 53
is a sulfuric acid ion exchange stage designed to remove
rhenium from overflow 46 and/or leach recycle stream 52.
With reference again to FIG. 1, SX feed stream 54 may be
filtered in one or more optional filtration stages 56 before
proceeding to SX circuit 50. SX circuit 50 may be adapted to
extract molybdenum (Mo), rhenium (Re), and/or other metal
values (e.g., rare earth metals) from the SX feed stream 54. 55
Overflow 46 may include additional metal values or other
compositions that are commercially valuable or otherwise
useful in an operator's facility. For example, overflow 46 that
becomes SX feed stream 54 may include copper, iron, or
other metal values that were contained in the original ore 60
and/or gangue. Depending on the composition of overflow
46, optional filtration stages 56 may be adapted to remove one
or more of such metal values or other compositions. Additionally
or alternatively, optional filtration stages 56 may be
adapted to remove some or all of the relatively invaluable 65
contaminants from overflow 46, such as contaminants that
may be remaining from the initial MoS2 supply. In some
US 7,824,633 B2
11
stripping step 216. However, other suitable stripping agents
76 may be used to put the Mo, Re, and/or other values back
into an aqueous solution for further processing.
A particular stripping agent 76 used may be selected based
on the organic used in the SX circuit 50, on any subsequent
processing stages 78 to which a stripped aqueous solution 80
will be subjected, and/or on other factors, such as cost and
efficiency. However, alkali metal and alkaline earth metal
basic solutions are thought to be particularly advantageous,
because they enable relatively lower acid concentrations, and
hence less corrosive conditions, to be maintained in the pressure
leach vessel 210 and subsequent processing stages. Thus,
equipment used for steps 210, 212, 214, and 216 may last
longer, and therefore an overall production costs of molybdenum
oxide may also be reduced. Subsequent processing
stages 78 may include a variety of suitable apparatus adapted
to upgrade the rhenium and/or the molybdenum values
according to the desired end product. As illustrated in FIG. 1,
stripping agent 76 may be provided from a supply tank 82.
Additionally or alternatively, stripping agent 76 may be supplied
from other sources, such as recycle streams from one or
more other process steps operated by the implementers ofthe
present invention. In addition to stripping the desired Mo
and/or Re values into the aqueous stage, stripping agent 76
may free the organic stage for other uses, such as optional
recycle stream 64 discussed above for use in SX circuit 50.
Aqueous alkali metal base including the Mo and Re values
may then be further processed for final upgrading ofrhenium
and molybdenum.
As illustrated, a portion ofstripped aqueous stream 80 may
be recycled back to pressure leach vessel 20 and/or feed
stream 23. Recycling a portion of stream 80 is advantageous
because it increases the effective yield recovery ofthe molybdenum
trioxide to the solid phase from system 10 and process
200.
System 10 and process 200 optionally respectfully include
an alkali metal (e.g., a sodium) removal apparatus and step
218. An exemplary removal step 218 employs an ion-exchange
on a strong cation resin system 83 to remove at least
some ofthe alkali metal ions before recycling a portion stripping
discharge 80 to pressure leach vessel 20 or feed stream
23.
Returning now to solid-liquid separation stage 40
described above, underflow 48 and its subsequent processing
will be described. Underflow 48 may include a substantial
portion of the solids from leach product stream 38. As
described above, underflow 48 generally comes from the
solids product of the last thickener 44 in the series of thickeners
in the stage 40. Additionally or alternatively underflow
48 may include some or all of the solids product of the last
thickener 44 together with one or more other components,
such as portions of the solids product from upstream thickeners.
Underflow 48 may be directed to a filtration unit 84 (e.g., a
CCD filtration unit), which may comprise any suitable combination
of components to accomplish the desired filtration.
Exemplary configurations of filtration unit 84 include one or
more rotating drums, belts, pressure filters, or other conventional
filters. A filtrate 86 from unit 84 may be returned to
stage 40 as recycle stream 88 and/or may be directed to
solution extraction circuit 50 as an SX feed stream 90. Relative
proportions of filtrate 86 that are utilized as recycle
stream 88 and SX feed stream 90 may be customized by an
implementer of the present invention to optimize the use of
filtrate 86.
A filter cake 92 from filtration unit 84 may include molybdenum
oxide (e.g., a primarily chemical grade oxide (CGO))
12
product 94. Product 94 may be directly utilized, such as in
products, processes, or other uses; may be directly commercialized,
such as sold to other entities as a finished product for
their use; and/or may be further processed in systems for
further refinement to Mo chemicals, such as ammonium
dimolybdate (ADM). The various possible uses ofproduct 94
are represented collectively and schematically as additional
products 96.
As one example of additional processing of oxide product
10 94, wet filter cake 92 from filtration unit 84 described above
may be further processed to produce one or more metallurgical
products, an ammonium dimolybdate (ADM) product,
and the like. A schematic block diagram of a system 100 for
producingADM is illustrated in FIG. 3. System 100 is merely
15 illustrative of the various additional products 96 that may be
implemented. As illustrated in FIG. 3, product 94 is delivered
to system 100 from a supply 98. When system 100 is in close
geographic and temporal proximity to system 10 described
above, system 100 may be fluidly coupled to system 10, such
20 that product 94 is delivered to system 100 directly from
filtration unit 84. However, system 100 may be offset from
system 10 for a number reasons that may lead to storing filter
cake 92 from filtration unit 84 for a period of time before
supplying cake 92 to system 100. In such circumstances, filter
25 cake 92 may be stored, and in some circumstances shipped,
before being utilized as supply 98 shown in FIG. 3. Additionally
or alternatively, product 94 illustrated as entering system
100 may be provided from a variety of other sources not
limited to production system 10 or process 200 described
30 above.
Regardless of the source of product 94 to system 100,
product 94 will commonly be supplied in the form of a wet
filter cake; however, product 94 may be in other forms, such
as dried and palletized product. Product 94, whether in the
35 form of a wet filter cake or otherwise, is supplied to a dissolver
tank 102. Suitable conditions in the dissolver tank 102
will typically include elevated temperatures with some agitation.
Such reaction conditions may be maintained through a
variety of suitable equipment and component configurations.
40 In dissolver tank 102, product 94 may be batch leached with,
e.g., an aqueous solution ofammonium hydroxide (NH40H)
104 from a source 106 to produce ammonium dimolybdate
(ADM), (NH4)2M0207, in solution. Product 94 may also be
continuously leached in a similar manner depending on the
45 operating conditions. In some implementations ofthe present
embodiment, system 100 may be adapted to selectively leach
product 94 in batch or continuous mode depending on other
process conditions.
As suggested by the foregoing discussion, product 94 and
50 ammonium hydroxide 104 react in dissolver tank 102 to
produce a leached slurry 110 that is directed from dissolver
tank 102 to an ADM filtration system 112. Product 94 may
include contaminants and impurities, some ofwhich may not
react in dissolver tank 102. Exemplary solid impurities that
55 may be present in product 94 include sulfide minerals and
non-hexavalent molybdenum, which may not react in dissolver
tank 102.ADMfiltration system 112 may be adapted to
separate the ADM in an aqueous solution filtrate 114 from
contaminants and other materials in a filter cake 116. Various
60 components and subcomponents may be incorporated in filtration
system 112 to accomplish the desired separation. One
exemplary ADM filtration system 112 includes a continuous
belt pressure filter. Filter cake 116 from ADM filtration system
112 may be directed to a downgrade circuit 118, which
65 may consist oftwo dryers operated in parallel. Other suitable
equipment may be included in downgrade circuit 118 to convert
filter cake 116 into a downgraded oxide 120. DownUS
7,824,633 B2
13
graded oxide 120 may be packaged and sold to customers as
a low-grade metallurgical oxide 122 or the like.
ADM filtrate 114 from ADM filtration system 112 may
proceed to an adjustment tank system 124, which includes a
pH adjustment tank. A discharge 126 from adjustment tank
system 124 is directed to a crystallizer system 128.
Returning to crystallizer system 128, crystallizing may be
performed in one ormore parallel crystallizers operating at an
elevated temperature. Additional or fewer crystallizers may 10
be used depending on the configuration of the overall system
and the intended feeds and outputs from crystallizer system
128. Similarly, the temperature and other conditions in crystallizer
system 128 may be varied to suit the other process
configuration variables and the variables that may be present 15
in the feed stream to crystallizer system 128. As illustrated in
FIG. 3, crystallizer system 128 may also produce a recycled
ammonium hydroxide stream 108, which may be recovered
from the vapors leaving crystallizer system 128. Recycled
ammonium hydroxide stream 108 from crystallizer system 20
128 is merely one example ofthe various efficiencies that may
be obtained through recycle streams and other techniques to
optimize the system 100.
In addition to the vapor stream/recycled ammonium 25
hydroxide stream 108 produced by crystallizer system 128, a
crystallizer output stream 132 may be produced by crystallizer
system 128, which output stream 132 may comprise
crystals in solution. Crystallizer output stream 132 may be
directed to a centrifugal separation system 134. The crystals 30
in solution may be separated from the solution in any suitable
manner, with centrifugal separation being a non-limiting
example of suitable separation systems.
Accordingly, centrifugal separation system 134 may
include two or more types of centrifuges and/or two or more 35
groups ofcentrifuges dedicated to different separation objectives.
With continued reference to FIG. 3, centrifugal separation
system 134 may be adapted to produce anADM product
stream 138. After exiting centrifugal separation system 134, 40
ADM product 138 proceeds to an ADM drying stage 140,
which may consist oftwo rotary kiln dryers operated in parallel
configuration at a temperature ofbetween about 1600 F.
and about 1700 F. Other suitable equipment and/or conditions
may be utilized in ADM drying stage 140. For example, in 45
some systems, it may be desirable to limit the temperature to
less than about 1750 F.
It is believed that the disclosure set forth above encompasses
at least one distinct invention with independent utility.
While the invention has been disclosed in the exemplary 50
forms, the specific embodiments thereof as disclosed and
illustrated herein are not to be considered in a limiting sense
as numerous variations are possible. The subject matter ofthe
inventions includes all novel and non-obvious combinations
and subcombinations of the various elements, features, func- 55
tions and/or properties disclosed herein.
The method and system described herein may be implemented
to convert molybdenum sulfide into molybdenum
oxide. Additionally, the present method and system may be
utilized to further refine the oxide to produce low-grade met- 60
allurgical oxide and/or annnonium dimolybdate. Additionally,
the present method and system may be implemented to
isolate copper and/or other metal values from the initial
molybdenum sulfide concentrate materials. Other advantages
and features of the present systems and methods may be 65
appreciated from the disclosure herein and the implementation
of the method and system.
14
We claim:
1. A method of forming molybdenum oxide from material
including molybdenum sulfide, the method comprising the
steps of:
providing a material including molybdenum sulfide;
pressure leaching the material including molybdenum sulfide
to form a pressure leach discharge comprising pressure
leach discharge solids and pressure leach discharge
liquid;
separating the pressure leach discharge solids and the pressure
leach discharge liquid to form a separated liquid and
separated solids comprising molybdenum oxide;
extracting at least one soluble metal value from the separated
liquid to form a loaded stream;
stripping the loaded stream using a basic solution to form a
stripped solution;
separating a molybdenum value from the stripped solution;
and
recovering the molybdenum value separated from the
stripped solution.
2. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
the step of deoiling the material including molybdenum
sulfide.
3. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
the step of upgrading the material including molybdenum
sulfide.
4. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
the step ofrecycling a stream ofthe stripped solution
to the pressure leaching of the material including molybdenum
sulfide.
5. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, wherein the
step of extracting at least soluble metal value comprises
extracting at least one metal value using an organic stage.
6. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, wherein the
step of extracting the at least soluble metal value, further
comprises a sub-step of extracting at least one additional
material.
7. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 6, wherein the
sub-step of extracting the at least one additional material
comprises extracting at least one of molybdenum, rhenium,
and rare earth metal.
8. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, wherein the
step of extracting soluble metal comprises using a technique
selected from the group consisting of solution extraction and
ion exchange.
9. The method of forming molybdenum oxide from material
including molybdenum sulfide of claim 1, wherein the
step of extracting the at least one soluble metal value comprises
using solution extraction.
10. The method offorming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
a step of recycling at least a portion of the separated
liquid to the pressure leaching the material including molybdenum
sulfide.
11. The method offorming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
a step of processing the molybdenum oxide to form
additional products.
12. The method offorming molybdenum oxide from material
including molybdenum sulfide of claim 11, wherein the
US 7,824,633 B2
15
step of processing the molybdenum oxide to form additional
products comprises fonning ammonium dimolybdate.
13. The method offorming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
the step of removing alkali metal ions from the 5
stripped solution.
16
14. The method offorming molybdenum oxide from material
including molybdenum sulfide of claim 1, further comprising
the step ofremoving additional materials from a discharge
stream of a solvent extraction process.
* * * * *