AU698786B2 - Process for the recovery of molybdenum from impure calcium molybdate resulting from the treatment of uraniferous ores - Google Patents
Process for the recovery of molybdenum from impure calcium molybdate resulting from the treatment of uraniferous ores Download PDFInfo
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- AU698786B2 AU698786B2 AU24854/95A AU2485495A AU698786B2 AU 698786 B2 AU698786 B2 AU 698786B2 AU 24854/95 A AU24854/95 A AU 24854/95A AU 2485495 A AU2485495 A AU 2485495A AU 698786 B2 AU698786 B2 AU 698786B2
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- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 title claims description 40
- 229910052750 molybdenum Inorganic materials 0.000 title claims description 40
- 239000011733 molybdenum Substances 0.000 title claims description 40
- 238000000034 method Methods 0.000 title claims description 23
- BIOOACNPATUQFW-UHFFFAOYSA-N calcium;dioxido(dioxo)molybdenum Chemical compound [Ca+2].[O-][Mo]([O-])(=O)=O BIOOACNPATUQFW-UHFFFAOYSA-N 0.000 title claims description 22
- 238000011084 recovery Methods 0.000 title claims description 8
- 239000000243 solution Substances 0.000 claims description 56
- 239000003960 organic solvent Substances 0.000 claims description 31
- 238000000605 extraction Methods 0.000 claims description 28
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 26
- 235000011149 sulphuric acid Nutrition 0.000 claims description 26
- 239000001117 sulphuric acid Substances 0.000 claims description 25
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 22
- 239000007864 aqueous solution Substances 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 14
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 11
- 239000002904 solvent Substances 0.000 claims description 8
- SEGLCEQVOFDUPX-UHFFFAOYSA-N di-(2-ethylhexyl)phosphoric acid Chemical compound CCCCC(CC)COP(O)(=O)OCC(CC)CCCC SEGLCEQVOFDUPX-UHFFFAOYSA-N 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- -1 tertiary amine salts Chemical class 0.000 claims description 4
- MPQXHAGKBWFSNV-UHFFFAOYSA-N oxidophosphanium Chemical class [PH3]=O MPQXHAGKBWFSNV-UHFFFAOYSA-N 0.000 claims description 3
- STCOOQWBFONSKY-UHFFFAOYSA-N tributyl phosphate Chemical compound CCCCOP(=O)(OCCCC)OCCCC STCOOQWBFONSKY-UHFFFAOYSA-N 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims 1
- 238000009434 installation Methods 0.000 description 9
- 235000011007 phosphoric acid Nutrition 0.000 description 9
- 229910052770 Uranium Inorganic materials 0.000 description 8
- 239000002253 acid Chemical group 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 239000008346 aqueous phase Substances 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 4
- 229910052720 vanadium Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 239000012074 organic phase Substances 0.000 description 3
- 230000020477 pH reduction Effects 0.000 description 3
- BZJTUOGZUKFLQT-UHFFFAOYSA-N 1,3,5,7-tetramethylcyclooctane Chemical group CC1CC(C)CC(C)CC(C)C1 BZJTUOGZUKFLQT-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000003085 diluting agent Substances 0.000 description 2
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 1
- 229940010552 ammonium molybdate Drugs 0.000 description 1
- 235000018660 ammonium molybdate Nutrition 0.000 description 1
- 239000011609 ammonium molybdate Substances 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 150000001450 anions Chemical group 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000005202 decontamination Methods 0.000 description 1
- 230000003588 decontaminative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004993 emission spectroscopy Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Inorganic materials O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 150000003016 phosphoric acids Chemical class 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- WQEVDHBJGNOKKO-UHFFFAOYSA-K vanadic acid Chemical compound O[V](O)(O)=O WQEVDHBJGNOKKO-UHFFFAOYSA-K 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/30—Obtaining chromium, molybdenum or tungsten
- C22B34/34—Obtaining molybdenum
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G39/00—Compounds of molybdenum
- C01G39/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Description
-s--A 1
AUSTRALIA
Patents Act 1990 COMMISSARIAT A L'ENERGIE ATOMIQUE
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT C o C- fc Ce C 0 CC 0 C C t C.
LCCC
f t t cle ci iae C Cl C C Cit C C *C C Invention Title: "Process for the recovery of molybdenum from impure calcium molybdate resulting from the treatment of uraniferous ores" The following statement is a full description of this invention including the best method of performing it known to us:- -i
I
m~I iq
DESCRIPTION
The present invention relates to a process for the recovery of molybdenum from impure calcium molybdate resulting from the treatment of uraniferous ores.
In the uranium industry and in particular in hydrometallurgical processes, carbonated solutions are produced which contain uranium and various metals such as molybdenum, which it is necessary to separate from the uranium.
This separation can be performed after acidification by precipitation with lime, which leads to the formation of an impure calcium molybdate precipitate, which more particularly contains impurities such as Si, P and/or V liable to form complexes of the heteropolyanionic type with molybdenum.
In order to recover the molybdenum from this precipitate, it is necessary to dissolve the latter in a sulphuric solution and then extract the molybdenum present in said solution, particularly in the form of heteropolyanions and/or isopolyanions, by means of an appropriate organic solvent.
20 FR-A-2 691 373 describes a process for the recovery of *molybdenum using these stages of dissolving and extracting by solvent. According to said document, the impure calcium S.,i molybdate is firstly dissolved in an aqueous sulphuric acid solution at approximately 0.25 mole/e, i.e. a pH-value close to 2 after dissolving and then the molybdenum i dissolved in the aqueous solution is extracted in an organic solvent comprising a first extractant constituted by a dialkyl phosphoric acid such as di-(2-ethylhexyl)- U phosphoric acid and a second extractant chosen from tertiary amine salts, quaternary ammonium salts, tributyl i phosphate and phosphine oxides.
1 K
I
2 This process suffers from the disadvantage of requiring the use of an organic solvent incorporating two extractant types in order to achieve satisfactory extraction yields.
Thus, due to the presence of heteropolymolybdic components in the aqueous dissolving solution, firstly there is a transfer of molybdenum heteropolyanions into the organic phase by means of the second extractant in anion or acid form as a function of the nature of the second extractant and then the proton form of the polynuclear anionic molybdenum complex in the organic phase into a dialkyl phosphoric (MoO 2 acid complex by means of the first extractant, whilst releasing the phosphoric acid, vanadic acid and/or orthosilicic acid, as well as the water in the aqueous phase.
US-A-3 751 555 and US-A-4 275 039 also illustrates the use of an organic solvent having two extractant types, such as di-(2-ethylhexyl) phosphoric acid and tributyl phosphate in order to recover the molybdenum from the molybdite or scheelite.
t*"h Throughout this specification, unless the context requires otherwise, i the word "comprise", or variations such as "comprises" or "comprising", will 15 be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
SUMMARY OF THE INVENTION The present invention specifically relates to a process for the recovery i 20 of molybdenum from impure calcium molybdate by dissolving and then S. extracting in an organic solvent, which avoids the formation of heteropolyanion complexes between the molybdenum and the impurities such as silicon, phosphorus and/or vanadium present in the starting calcium molybdate, whilst as a result simplifying the molybdenum extraction procedure and at the same time obtaining very good extraction yields.
In one aspect, the present invention is directed to a process for the i recovery of molybdenum present in impure calcium molybdate obtained from the treatment of unaniferous ores, characterized in that it comprises the j following successive steps:
L
SUi <3 ~.1 a) dissolving the calcium molybdate in an aqueous sulphuric acid solution having a sulphuric acid concentration of at least two mole/e, b) contacting the aqueous dissolving solution from step a) with an organic solvent incorporating a dialkyl phosphoric acid, with the proviso that the organic solvent does not also include tertiary amine salts, quaternary ammonium salts, tributyl phosphate or phosphine oxides; and 4
S
4 4
S
.4.
4 4 4e 44 4 4 44 4 44 '4 i-
SLP
r i Ir i r A C~..r
TZIF
I Wfn *11A4~T P 4'Th 1; U* I~LII~LYII) 3 c) separating from the aqueous solution the organic solvent which has extracted the molybdenum.
In this process, the use of an aqueous solution having at least 2 mole/e of sulphuric acid, e.g. 2 to 4 mole/1 of sulphuric acid for dissolving the calcium molybdate avoids the formation of heteropolymolybdic components in the dissolving solution. Therefore it is no longer necessary to then use for the extraction of the molybdenum two extractants in order to ensure on the one hand the transfer of the heteropolymolybdic components into the solvent and on the other their transformation into the dialkyl phosphoric (Mo 0 2 acid complex.
Thus, it has been found that the existence range in aqueous solution of heteropolymolybdic components was in the pH range 1 to 3, which corresponds to sulphuric acid concentrations of 0.2 to 2 mole/ and that the degradation of the components formed by the subsequent acidification of the solution was very slow.
In addition, by performing in accordance with the present invention the dissolving of the calcium molybdate with a sulphuric acid concentration above 2 mole/?, troublesome heteropolybdic components are not formed.
After dissolving the calcium molybdate in the aqueous sulphuric acid solution, said solution is contacted with an organic solvent incorporating a dialkyl phosphoric acid.
In general, the organic solvent is constituted by a dialkyl phosphoric acid solution in an appropriate organic diluent.
The dialkyl phosphoric acids which can be used are those in which the alkyl radicals are straight or branched radicals with 4 to 16 carbon atoms.
As an example of such an acid reference can be made to di-(2-ethylhexyl)-phosphoric acid, which is hereinafter designated by the abbreviation HDEHP.
The organic diluents used are e.g. aliphatic or aromatic hydrocarbons, e.g. hydrogenated tetrapropylene
(TPH).
*e *0 tt t C
C
C.
PC
V
14 4 The dialkyl phosphoric acid concentration of the organic solvent is generally high, because the extraction rate increases with the extractant content. Preferably, the dialkyl phosphoric acid concentration is 15 to vol. According to the invention after contacting the organic solvent with the dissolving solution, an organic solvent is obtained which contains the extracted molybdenum.
Preferably said solvent is washed with an aqueous, dilute sulphuric acid solution, e.g. having a sulphuric acid concentration of 0.5 to 1 mole/e. The molybdenum can then be reextracted from the organic solvent by means of an aqueous ammoniacal solution.
The process according to the invention can be performed in conventional cocurrent or countercurrent extraction installations such as mixer-settlers, pulsed columns, etc.
It is possible to carry out contacting at ambient pressure and temperature, but it is also possible to use higher temperatures, particularly for improving the extraction kinetics..
It is also possible to operate continuously by bringing about a countercurrent circulation of the organic 25 solvent and the aqueous solutions and recycling the aqueous washing solution of the organic solvent with the starting aqueous solution containing the molybdenum to be extracted.
Other features and advantages of the invention can be better gathered from the following non-limitative descrip- 30 tion with reference to the attached drawings, wherein show: Fig. 1 A diagram representing the heteropolymolybdic complex quantities present in a sulphuric medium as a function of the sulphuric acid concentration of the medium (in mole/e).
Fig. 2 A diagrammatic representation of an exemplified embodiment of the process of the invention.
4, 4 Su S *54*O *1 S*
S.
**8 S S 4J4 4 o S rC( 1~1 Fig. 3 A diagrammatic representation of another embodiment of the process of the invention.
Fig.'1 illustrates the behaviour of the following heteropolymolybdic complexes: phosphomolybdic complex (Mo:P atomic ratio 20:1) absorbing at 400 nm, phosphovanadomolybdic complex (Mo:P:V atomic ratio 11:1:1) absorbing at 490 nm, and silicomolybdic complex (Mo:Si atomic ratio 12:1) absorbing at 430 nm, at a concentration of 0.1 mole/e'of Mo(VI) in an aqueous sulphuric acid solution, as a function of the H2SO4 concentration (in mole/e).
The abundance of the complex in solution is represented by the optical density of the solution at the wavelength corresponding to the absorption peak of the considered complex.
In Fig. 1, curve 1 relates to the phosphomolybdic complex, curve 2 to the phosphovanadomolybdic complex and curve 3 to silicomolybdic complex.
Thus, it can be seen that beyond a sulphuric acid concentration of 2 mole/e, there is no longer any complex in solution.
This is why, according to the invention, use is made for the purpose of dissolving the calcium molybdate of an aqueous sulphuric acid solution having a HSO 4 concentration of at least 2 mole/e.
Thus, the dissolving solution incorporates virtually no heteropolymolybdic components. This result cannot be 30 achieved rapidly by carrying out the dissolving with a dilute H2SO 4 solution and then acidifying the dissolving solution, because it is found that these heteropolymolybdic components and in particular silicomolybdic components have an excessively slow degradation kinetics in concentrated acid medium. For example, a period of 15 days is necessary 6466 4* 6 6r *c o *r I o 4 ac i:: i.
~rF I C
F
L C- L I C 6 at ambient temperature in order to degrade silicomolybdic components in a 3M sulphuric medium.
The following examples illustrate the results obtained with the process of the invention.
EXAMPLE 1: DISSOLVING CALCIUM MOLYBDATE In this example, Ig of calcium molybdate having the composition given in the following Table 1 is dissolved in of an aqueous solution containing 3 mole/? of sulphuric acid, accompanied by stirring, at ambient temperature and the composition of the dissolving solution is checked by periodically taking samples and analyzing them by spectrophotometry and emission spectroscopy JCP for determining their Mo, P, V, Si and U contents.
After stirring for 45 minutes, the dissolving yield no longer undergoes any significant variation and a dissolving solution is obtained having the Mo, P, V, Si and U concentrations given in Table 1.
This Table includes for comparison purposes the results obtained when carrying out the dissolving under the same conditions, but using a 0.25 mole/e sulphuric acid S" 20 solution (pH 2) as in FR-A-2 691 373.
TABLE 1 CALCIUM DISSOLVING DISSOLVING ELEMENT MOLYBDATE SOLUTION SOLUTION 3 mole/1 H 2 SO H 2
SO
4 (pH=2) 25 (in mole/e) (in mole/e) Mo 33.660 0.212 0.159 P 1.360 5.9910- 3 1.10e10- 2 V 1.610 1.69*10- 2 1.49,10- 2 Si 0.760 1.81r10- 3 5.80*10' 3 U 0.378 7.04.10- 4 7.10- 4
I
I
mm 7 The results of Table 1 show that according to the invention an increased molybdenum dissolving is obtained.
EXAMPLE 2: MOLYBDENUM EXTRACTION Contacting takes place, accompanied by stirring, of one volume of a dissolving solution obtained as in example 1 either with 2M H SO4 or with 3M H 2
SO
4 four days after it was obtained, with 1 volume of an organic solvent consisting of 30 vol.% di-(2-ethylhexyl)-phosphoric acid and vol.% of hydrogenated tetrapropylene.
After stirring for 5 minutes at 230C, the two phases are allowed to settle and their respective molybdenum contents are determined. This operation is repeated twice contacting the aqueous solution separated from the organic solvent resulting from the preceding contact with 1 volume of new organic solvent.
The composition of the starting solution and the results obtained are given in Table 2. In this Table, the extraction yields correspond to the cumulative values ob- 'tained after 1, 2 or 3 contacts.
This Table gives for comparison purposes the results 20 obtained when working in the same way with a dissolving solution having a H2SO 4 concentration of 1 mole/e.
*4 4 4 S*4 I 1 |1 p 8 TABLE 2
DISSOLVING
SOLUTION
After 1 contact After 2 contacts
H
2 SO4 (in mole/e) Mo(VI) in mole/e Organic Mo(VI) (in mole/e) Aqueous Mo(VI) (in mole/e) Extraction yield Organic Mo(VI) (in mole/e) Aqueous Mo(VI) (in mole/e) Extraction yield Organic Mo(VI) (in mole/e) Aqueous Mo(VI) (in mole/1) Extraction yield 1 0.161 0.165 0.15 0.0753 0.135 0.129 0.0857 0.030 0.021 46.7% 81.8% 86% 0.0315 0.0164 0.0129 0.0542 0.0136 0.0081 4*t4 *4 *4.
4 44 0 .4 4.
4. 4 4 66.3% 91.7% 94.6% After 3 contacts 0.0236 0.0028 0.0017 0.0306 0.0108 0.0061 80.9% 93.4% 95.9% The results of Table 2 show that better results are obtained with the dissolving solutions obtained according to the process of the invention.
EXAMPLE 3: In this example the molybdenum is recovered from a dissolving solution obtained according to the invention, by using the installation operating in continuous manner and in countercurrent form, as is diagrammatically shown in Fig. 2.
1 -'9 MEL- I 11 Z 71-1_- .4 er rcC Cii 9 This installation comprises an extraction stage 21 and a washing stage 23 in which the organic solvent flows continuously, being introduced by the pipe 25. In this extraction stage, the organic solvent is countercurrent contacted with the dissolving solution of the calcium molybdate stored in the tank 27. This solution is introduced by the pipe 29 in the extraction stage 21.
On leaving the extraction stage pipe 31 recovers an aqueous effluent containing P, Si, V and U and virtually no molybdenum and by the pipe 33 the organic solvent containing molybdenum, as well as a few impurities.
At the washing stage 23, this organic solvent is brought into countercurrent contact with an aqueous washing solution, e.g. a 0.5 mole/e sulphuric acid solution, introduced by the pipe On leaving the washing stage pipe 37 recovers the molybdenum-containing organic solvent and pipe 39 an aqueous effluent containing the impurities deextracted from the solvent.
20 In this installation it is possible to use circulation flow rates such that the volume ratio of the organic phase to the aqueous phase is 2 in the extraction stage and in the washing stage.
This stage can be constituted by several individual stages each constituted by a mixer-settler. For example, the extraction stage can have 12 individual stages and the washing stage 4 individual stages.
In the following Table 3 are given the results obtained in this installation with a 3 mole/e sulphuric acid dissolving solution. For comparison purposes this Table also gives the results obtained with a dissolving solution in a weakly acid medium (pH then acidified in order to have a 3 mole/e sulphuric acid concentration. In this Table, the extraction yields are calculated on the basis of concentrations measured on the different aqueous phases.
i.
V- V Y"r m a
C
a S TABLE 3 Mo (VI) concentration (mole/1) yiel)A Ref lux ratio(*) Dissolving solution (3 mole/i) H 2so4 dissolving solution (3 mole/i) On entry (in 29) Extraction effluent (in 31) Washing effluent (in 39) Organic solvent (in 37) 6. 1 *10-4 0.212 2.2.10 0.10 99.7 0.05 1 .056 Dissolving solution (pH2) acidified to 3 mole/i in H 2so4 0.138 1.5.102 2.90*10- 5.55.102 88.1 1 .08 Mo flow (mole/h) in the aqueous phase to be treated Reflux ratio Mo flow (mole/h) in the dissolving solution entering the extraction operation
E/S
-Entering Mo flow Y departing Mo flow I I~t, I"i ft. C *9
C
*99*i
S.C
*4 4 94 4* o *4 *r 4 a *4 C 4 11 The results of Table 3 demonstrate that an extraction yield of 99.7% is obtained with the process according to the invention, whereas it is well below this figure (88%) when the dissolving is carried out at pH 2, followed by an acidification to 3 mole/e of H 2
S
4 EXAMPLE 4: In this example, the dissolving and then the extraction of the molybdenum take place from calcium molybdate, using the installation diagrammatically shown in Fig. 3.
Fig. 3 uses the same references as in Fig. 2 for designating the components common to both installations.
In this installation, firstly the calcium molybdate is dissolved in the container 40 using 20 m 3 of 3M H 2
SO
4 per tonne of calcium molybdate. Dissolving is carried out, accompanied by stirring, for 1 hour and at 23 0 C and then the solution is separated from solid materials by filtration in the filter 42.
The separated solution containing approximately 0.2 mole/e of molybdenum and impurities U, Si, P) is supplied by the pipe 29 to the extraction stage 21, which 20 consists of six individual stages with the washing solution leaving the washing stage 23.
The organic solvent (30% HDEHP 70% THP) is introduced by the pipe 25 and circulates in countercurrent manner with the aqueous solution.
25 On leaving the extraction stage 21, it is introduced into the washing stage 23 consisting of four individual stages, where it is countercurrent contacted with a 1 mole/1 H 2 SO aqueous solution introduced by the pipe On leaving the washing stage 23, the organic solvent, which virtually contains no molybdenum, is treated with a view to recovering the molybdenum by deextraction in an ammoniacal medium (pH 8.5 to 9) and then undergoes decontamination with respect to uranium in a carbonate medium.
It is then reacidified by H 2 SO4 and recycled to extraction stage 21. However, it is possible to avoid this i' i 3rrr r' i j e i 12 reacidification of the solvent, because the latter can be performed by the aqueous solution in the first extraction stage.
The molybdenum can be separated from the ammoniacal solution by ammonium molybdate precipitation in the acid medium (pH s 1).
Fig. 3 indicates the volumes of solutions introduced at this stage.
With this installation, molybdenum is recovered with a yield of 99.7% using a single extractant.
4* L *1 t *0a I *o *1 r* 64 c *i 4e *4 4 I I *r 94P 9 9 9. 4 9* 4 94**
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Claims (5)
1. Process for the recovery of molybdenum present in impure calcium molybdate obtained from the treatment of uraniferous ores, characterized in that it comprises the following successive steps: a) dissolving the calcium molybdate in an aqueous sulphuric acid solution having a sulphuric acid concentration of at least 2 mole/e, b) contacting the aqueous dissolving solution from stage a) with an organic solvent incorporating a dialkyl phosphoric acid with the proviso that the organic solvent does not also include tertiary amine salts, quaternary ammoniumi salts, tributyl phosphate or phosphine oxides; and c) separating from the aqueous solution the organic solvent which has extracted the molybdenum.
2. Process according to claim 1, characterized in that the sulphuric acid concentrations of the aqueous solution used in step a) is 2 to 4 mole/ e 15
3. Process according to claim 1 or 2, characterized in that the dialkyl phosphoric acid is di-(2-ethylhexyl)-phosphoric acid.
4. Process according to any one of claims 1 to 3, characterized in that it involves a supplementary washing stage of the organic solvent which has extracted the molybdenum by an aqueous solution constituted by dilute 20 sulphuric acid.
5. Process according to claim 4, characterized in that the sulphuric acid concentration of the washing solution is 0.5 to 1 mole/ C. ao.. DATED this 23rd day of September 1998 COMMISSARIAT A L'ENERGIE ATOMIQUE Patent Attorneys for the Applicant: F.B. RICE CO. 1 k L t iI4i I' ,w *C' *1 DESCRIPTIVE ABSTRACT The invention relates to a process for the recovery of the molybdenum present in impure calcium molybdate result- ing from the treatment of uraniferous ores. According to this process (in 40) the calcium molyb- date is dissolved in an aqueous solution containing at least 2 mole/e of H2SO 4 and then the molybdenum is ex- tracted (in 21) in an organic solvent comprising a dialkyl phosphoric acid such as di-(2-ethylhexyl)-phosphoric acid. After extraction, it is possible to wash the solvent (in 23) using an aqueous sulphuric acid solution and then recover the molybdenum extracted in the reextraction solvent in an ammoniacal solution. The choice of a dissolving solution having a H SO 4 Sconcentration of at least 2 mole/I avoids the formation of S 15 difficultly extractable heteropolymolybdic components. i (Fig. 3) ai a tt 1 1
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9408986A FR2722701B1 (en) | 1994-07-20 | 1994-07-20 | PROCESS FOR THE RECOVERY OF MOLYBDENE FROM IMPURED CALCIUM MOLYBDATE FROM THE PROCESSING OF URANIFEROES |
| FR9408986 | 1994-07-20 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2485495A AU2485495A (en) | 1996-02-01 |
| AU698786B2 true AU698786B2 (en) | 1998-11-05 |
Family
ID=9465578
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU24854/95A Ceased AU698786B2 (en) | 1994-07-20 | 1995-07-05 | Process for the recovery of molybdenum from impure calcium molybdate resulting from the treatment of uraniferous ores |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU698786B2 (en) |
| CA (1) | CA2154133A1 (en) |
| FI (1) | FI953493A (en) |
| FR (1) | FR2722701B1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014332B (en) * | 2013-01-16 | 2015-03-11 | 四川顺应金属材料科技有限公司 | Pretreatment method for extracting molybdenum from molybdenum ore |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2691373A1 (en) * | 1992-05-21 | 1993-11-26 | Commissariat Energie Atomique | Molybdenum extn. and purificn from aq. solns. for uranium@ industry - by organic solvent extn. with two component system contg. prim. and sec. extractants of di:alkyl phosphoric acid and phosphine oxide |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL34112A0 (en) * | 1969-04-03 | 1970-07-19 | Atomic Energy Commission | Separation and purification of molybdenium-99 |
| JPS549193A (en) * | 1977-06-23 | 1979-01-23 | Daido Oxygen | Method of separating and recovering molybdnum and tungsten |
-
1994
- 1994-07-20 FR FR9408986A patent/FR2722701B1/en not_active Expired - Fee Related
-
1995
- 1995-07-05 AU AU24854/95A patent/AU698786B2/en not_active Ceased
- 1995-07-18 CA CA002154133A patent/CA2154133A1/en not_active Abandoned
- 1995-07-19 FI FI953493A patent/FI953493A/en unknown
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2691373A1 (en) * | 1992-05-21 | 1993-11-26 | Commissariat Energie Atomique | Molybdenum extn. and purificn from aq. solns. for uranium@ industry - by organic solvent extn. with two component system contg. prim. and sec. extractants of di:alkyl phosphoric acid and phosphine oxide |
Also Published As
| Publication number | Publication date |
|---|---|
| FI953493A (en) | 1996-01-21 |
| FI953493A0 (en) | 1995-07-19 |
| FR2722701B1 (en) | 1996-08-23 |
| CA2154133A1 (en) | 1996-04-18 |
| AU2485495A (en) | 1996-02-01 |
| FR2722701A1 (en) | 1996-01-26 |
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| Date | Code | Title | Description |
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| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |