NZ245854A

NZ245854A - Recovery of molybdenum and/or vanadium from used catalyst material by alkaline leaching, neutralisation and elution from an ion exchange resin

Info

Publication number: NZ245854A
Application number: NZ245854A
Authority: NZ
Inventors: Francois Ackermann; Georges Berrebi; Pierre Dufresne; Lierde Andre Van; Marc Foguenne
Original assignee: Eurecat Europ Retrait Catalys
Priority date: 1992-02-07
Filing date: 1993-02-05
Publication date: 1994-10-26
Also published as: FR2687170B1; FR2687170A1; JPH0657353A; EP0555128A1

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £45854 24 5854 I ' - o- Ci-L.esU3t».fi2.; C%Z$2lzt2tf.; 0o/Dnloz,' SoipifloH- | " /, '"" 26 Oct 1994 ; I'OJ .V , . I ... - ■ | P.C. Jo " 1 /$(.$. ' no Patents Form No. 5 NEW ZEALAND N-Z. PATtrtT OFF JOE ,,5 FEB 1303 U PATENTS ACT 1953 COMPLETE SPECIFICATION RECOVERY OF MOLYBDENUM AND VANADIUM FROM USED CATALYSTS WE, EUROPEENNE DE RETRAITEMENT DE CATALYSEURS EURECAT, a French company of Quai Jean Jaures, 07800 La Voulte Sur Rhone, FRANCE hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 - (followed by page la) / r' e\ EL a m 3 8 5# 1^ The present invention relates to the recovery of molybdenum and vanadium from used catalysts. The Applicant who has been involved for more than ten years in the 5 retreatment of used catalysts in the refining of petroleum has developed a technique enabling used catalysts of the hydro treatment, hydrocracking or hydrogenation kind, to be treated with a view to recovering the metals of the catalyst. 10 This technique makes it possible for all valuable metals to be recycled, such as molybdenum, vanadium, tungsten, cobalt and nickel, whilst by-products contained in the catalysts (arsenic, antimony, lead, silica, phosphorus, iron, aluminium, etc.) are removed by the use of techniques which are compatible with environmentally 15 dependent constraints. Said technique is a combination of pyrometallurgical and hydrometallurgical steps, the main features of which are use of the roasting techniques, already used for the regeneration of catalysts. 20 The used catalyst is roasted at a moderate temperature, and the heat released is recycled by the combustion of the sulphur and carbon contained in the treated catalyst. In this technique, the used catalyst is initially sifted in order to 25 remove all the foreign substances such as small inert balls. TMe catalyst is then conducted to a regeneration unit in order to remove all the hydrocarbons, sulphur and carbon by combustion. Regeneration takes place in a furnace at temperatures in excess of 30 500°C and with a large excess of air. The gaseous effluents are conveyed to a post-combustion chamber and burned at temperatures in excess of 850°C, then conveyed to conventional treatment installations: washers, cyclones, filters. . . (followed by page 2)' 0 /. -Zs £ ■ 2 After regeneration, the catalyst contains less than 0.1 % carbon and sulphur. At this stage, various methods have been proposed with a view to 5 recovering, more particularly, molybdenum and possibly vanadium. Proposals have been made, in particular, for leaching in basic medium, but methods such as these are inadequate for obtaining pure molybdenum and/or vanadium, also in pure state. 10 One prior art method consists in subjecting the catalyst to simple leaching with soda. The method is not ideal since the molybdenum recovered is impure owing to the simultaneous parasitic extraction of vanadium and alumina (which forms the catalyst support). 15 Another prior art method consists in roasting the used catalyst in alkaline medium (soda, for example) at about 750 °C in a furnace, for example. Alumina, molybdenum and soda are recovered during this step: leaching in water (percolation) is then carried out which permits leaching (dissolving) of the sodium molybdate, vanadate, 20 phosphate and arsenate. At this stage, the alumina is not greatly dissolved. The residue with a base of nickel and/or cobalt metals and alumina can be sold as such or treated with a view to extracting the nickel and/or cobalt (by pyrometallurgy, for example). 25 A final treatment of the solution with a neutral pH allows aluminrum and arsenic to be removed by precipitation, and significant quantities of sodium molybdate to be obtained. However, this molybdate is still contaminated with vanadium. 30 The technique proposed in the present invention by the Applicant proves to be the most effective as far as extraction yields of molybdenum and vanadium are concerned. During the special leaching operation of the invention (alkaline medium, temperature in the order of 90°C, more usually between 50 and 100 °C) said leaching is 35 carried out continuously, for example, at counter-current in a 24 585 3 series of at least two vats, three to twelve vats or more, for example, by percolation. The present invention relates to the recovery of molybdenum and vanadium from a used catalyst, and more particularly a process for the recovery of molybdenum in a substantially pure state and of vanadium in a substantially pure state when this latter metal is present in the used catalyst. 10 The invention is therefore a part of the stages of prior art processes for the recovery of other ingredients from used catalysts, such as cobalt and/or nickel, possibly tungsten and/or arsenic, etc. The process according to the invention which is part of, or which 15 follows, roasting of the catalyst, is different from other existing processes because it is flexible, easy to use, simple, inexpensive and because the production cost of the metals is relatively competitive. 20 Other current processes usually involve: high temperature roasting techniques followed by acid leaching. These processes are usually expensive in terms of energy, and investment costs are relatively high in view of the problems of 25 acid corrosion; high pressure leaching techniques in strong alkaline medium (autoclaving). The drawback with this process is the need to dissolve all the alumina and/or silica constituting the catalyst 30 support. The originality of the process according to the invention is the discerning combination of roasting, pyrometallurgical and hydrometallurgical techniques. 35 n sa ■V ~r <■* k Also, the first step of the roasting operation of the used catalyst plays a fundamental role in the rest of the treatment. This step is under perfect control, since it involves tried and tested regeneration techniques in a revolving furnace, and is a special 5 concern of the Applicant. Moreover, these techniques are advantageous in that they are able to be used directly in existing installations with special processes which have already been tested and checked for reliability. In the process according to the invention, vanadium and molybdenum are recovered ir. pure state with yields of above 90 %. In the present invention, with a view to obtaining substantially 15 pure molybdenum and possibly substantially pure vanadium from a used, dirty or polluted catalyst, said metals of molybdenum and vanadium are recovered in the following way, after or during the various conventional purification operations for the recovery of other ingredients from said catalyst (purification operations 20 mentioned hereinabove): a) the catalytic mass is subjected to alkaline leaching. Usually, the mass is then washed in water. During the actual leaching operation, the molybdate, vanadate, phosphate, arsenate, etc... are leached, that is to say they are dissolved. The alumina is 25 not greatly dissolved. At this stage, the residue containing nickel and/or cobalt and the alumina or silica-alumina support can be treated separately with a view to removing, in particular, nickel and/or cobalt. The leaching parameters (pH, redox potential, stay time, flow rates, concentrations, 30 liquid/solid ratio, etc.) are adjusted as a function of the catalyst, in order to prevent the alumina from dissolving too much. b) The solution obtained is brought to a pH value of about 7 by adding acid (preferably sulphuric acid) with a view to removing (by precipitation) the alumina and also possibly the phosphorus and arsenic which may be contained in the catalyst, and the present invention is characterised in that: c) the purified solution containing molybdenum and possibly vanadium is brought to a pH of about 4 to 5-5 and d) adsorption of this solution is carried out on an ion-exchange resin, at stabilised pH of about 4, e) elution is carried out in order to collect molybdenum in substantially pure state. If the catalyst contains both molybdenum and vanadium, during step (e) selective elution is carried out in two stages. During the first stage, elution is carried out in acid, reducing medium with a view to recovering substantially pure vanadium, and during the second elution stage, carried out in basic medium (preferably using ammonia or soda), substantially pure molybdenum is recovered. Table I gives an idea of the type of analyses and impurities contained in used catalysts. ^ 245854 Table I Analyses of the Types of Used Hydrotreatment Catalysts of Petroleum Cuts 5 HYDR0DESULPHURATI0N CATALYST HYDRODEMETALLATION CATALYST 10 A1 1« v/> by weight) 35 28 Mo (% by weight) 8.8 6.2 V c \ ft by weight) 1.2 10.5 Ni (« ^ /» by weight) 0.3 3.1 Co (% by weight) 3-2 2.1 15 W (% by weight) 0.1 0.1 Pb !» \fi by weight) 0.01 0.1 Si (f by weight) 0.5 1.2 Fe {% by weight) 0.2 0.7 As (% by weight) 0.01 0.1 20 P (% by weight) 0.03 0.05 Na (% by weight) 0.2 0.5 25 EXAMPLE This example illustrates steps (a) (leaching) and (b) (acid treatment with removal of aluminium). 30 LEACHING PARAMETERS Catalyst: type: hydrotreatment catalyst from Table I hereinabove 35 mass: 200 g Attack Solution: type : NaOH concentration : 60 gl1 volume : 150 ml kQ Operating Conditions: time : 3 hours temperature : 90°C 24 5 8 5 4 7 TABI.FI OF RESULTS (limited here to Mo, V, Al) Residue Solution Mass or volume 174.2 g 280 ml pH - 10.9 Mo content 1.59 % 39-6 g/1 V content 0.59 * 4.3 g/1 Al content 40.71 % 5.2 g/1 Free NaOH content - 13-6 g/1 20 Leaching yields: - Mo : 85.7 % V : 65.3 % - Al : 3-0 1 25 PARAMETERS OF PRECIPITATION TN ACID MEDIUM Test temperature: - 90 ° C Base solution: 30 - volume : 100 ml - pH : 11.80 Solution of H:SQh: - concentration : 100 g/1 - volume added : 13-7 ml it. ~ o v ■■ '* u > ' Evolution of dH: - from 11.8 to 7.00 Purified solution: - volume : 114 ml - pH : 6.6 Precipitate: - mass : 2.0 g TABLE OF RESULTS 10 15 20 contents content (g/1) (mg/1) Mo V Al As Leaching solution 31-35 3-40 4.13 27-3 Solution after purification 25-29 2.14 <0.05 0.8 PRECIPITATION YIELDS 25 Mo : 8.19 % ; Al : > 98.6 1 V : 28.2 % ; As : 96.7 X Example 2: This example illustrates steps (c) and (d) (adsorption of a 30 solution, such as that obtained in Exaaple 1, on an ion-exchange resin). 24 585 9 IONIC EXCHANGE PARAMETERS Resin : - name : Amberlite IRA 9^ S 5 - type : ion-exchange of low basicity - volume : 20 ml - conditioning : H2S04 60 g/1 for 1 hour Base solution : - leaching solution 10 - volume : 75 ">1 - pH : 5-00 Operating Parameters : - temperature : 18 ° C - duration : 1 hour 15 Purified solution: - volume : 75 - pH : 4.12 TABLE QF RESULTS 20 contents content (g/1) (mg/1) Mo V Al Si Ni • S As Base solution 14.69 1 • 77 0.75 <0.02 <0.005 11.2 2.0 •* Solution after 1.64 <0.05 0.23 <0.02 <0.005 10.7 <0.05 30 IQNIC EXCHANGE YIELDS Mo : 88.8 % Al : 69.3 % S* : 4.5 % V : > 97.2 % As : > 97-5 S This sulphur is in the form of sulphate. 35 10 Example 3: This example illustrates step (d) of the process (adapted here for the impregnation of molybdenum and vanadium on three columns in series) then step (e) for selective elution. 5 ADSORPTION ON THREE COLUMNS IN SERIES Resin : - name : Amberlite IRA 9^ SP 10 - volume : 200 ml - feed : low ^ high - three columns in series - conditioning : H2S04 60 g/1 for 1 h Solution for adsorbing : 15 - solution acidified with H2S04 - concentrations : 48 g/1 Mo and 3-90 g/1 V - flow rate : 400 ml/h - pH : 4 Operating Parameters : 20 - temperature : 45 °C .-i 5 4 11 TABLE OF RESULTS 10 15 20 25 30 Concentrations at exit from columns (g/1) Time Column 1 Column 2 Column 3 (hours) Mo V Mo V Mo V 0.37 <0.05 <0.05 - - - 0.75 <0.05 <0.05 - - - 1.12 5-36 0.35 - - - 1.5 40.84 3.42 - - - 1.87 40.24 3.46 - - - 2.25 44.16 3.76 <0.05 <0.05 2.62 45.19 3.88 1.29 <0.05 3 - - 35.96 2.89 - 3-37 - - 44.63 3-67 <0.05 <0.05 3-75 - - 45.37 3.64 0.11 <0.05 4.12 - - - - 2.79 <0.05 4.5 - - - - 18.08 0.93 4.87 - - - - 38.31 3-24 5-12 — 36.61 2.99 Total adsorption : - Mo : 99-9 kg/m3 resin - V : 10.9 kg/m3 resin 35 COLUMN ELUTION (1st step, elution of vanadium in acid medium) 40 Charge: -99-9 kg/ m3 Mo and 10.9 kg/a3 V Malms. : - 20 ail Temperature : - 55 °c </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 5854 12 Eluent Solution : - mixture S02 4X and H2S0i, 33-3 g/1 - flow rate : 20 ml/h 5 TABLE OF RESULTS ELUTION VOLUME PH ELUTION YIELDS YIELDS (ml) (%) COLLECTED (?) Mo V Mo V 21 1.09 0.18 41.31 0.18 41.31 20 1.07 0.23 53-13 0.4l 94.44 20 0.80 0.51 3-13 0.92 97-57 25 0.79 0.40 1.75 1.32 99.32 24 COLUMN ELUTION (2nd stage, elution of molybdenum in basic medium) Volume : 25 - 16 ml Eluent solution : - amnoniacal solution 70 g/1 NHa0H - pH : 12.35 - flow rate : 20 ml/hour 30 TABLE OF RESULTS Elution PH ELUTION YIELDS YIELDS yield (ml) {%) Mo COLLECTED {%) Mo 22 8.53 46.67 46.67 20 9.84 50.02 96.69 20 11-3 2.18 98.87 20 11.9 0.29 99.16 20 12.0 0.15 99.31 20 12.1 0.09 99-40 20 12.1 <0.06 99.46 22 12.0 0.1 99-56 45 30 ' A /' t - S ' • - ■ Ivj * J "V v_- , 13 WHAT WE CLAIM IS:- 

1. A process for the treatment of a used catalyst, containing molybdenum and vanadium, with a view to recovering said molybdenum and said vanadium in a substantially pure state, the process optionally comprising conventional steps for recovery of other ingredients in said catalyst, the process comprising a sequence of steps adapted for the recovery of molybdenum and vanadium, said process consisting of: a) subjecting the catalytic mass to alkaline leaching to dissolve the molybdate and vanadate, said leaching optionally being followed by washing in water, b) bringing the pH of the solution obtained to a value of about 7. and treating the solution with an acid to remove by precipitation the alumina which it contains, and any arsenic which it contains, the process then being characterised in that: c) the purified solution containing molybdenum and vanadium is brought to a pH of 4 to 5,5 and d) adsorption of this solution is carried out on an ion-exchange resin, and e) elution is carried out in two steps, the first step being carried out in an acid, reducing medium, during which elution step substantially pure vanadium is recovered, the second step being carried out in a basic medium, during which elution step substantially pure molybdenum is recovered.
2. A process according to Claim 1, wherein during the leaching operation carried out in alkaline medium, the temperature is between 50 and 100°C, and the operation is carried out continuously and at counter-current in a series of at least two vats by percolation.
3. A process according to Claim 2, wherein three to fifteen vats are used in series. 2 6 APR;994 If
4. A process according to any one of Claims 1 to 3, wherein during step (b) the acid is sulphuric acid.
5. A process according to any one of Claims 1 to 4, wherein the reducing agent used during step (e) is sulphur dioxide or hydrazine.
6. A process according to any one of Claims 1 to 5, wherein in step (e) the second step of the elution process is carried out in the presence of ammonia or soda.
7. A process as claimed in claim 1, substantially as herein described with reference to the Examples.
8. A product when produced according to the process as claimed in any one of claims 1-7 inclusive. EUROPEENNE DE RETRAITEMENT DE C^ALYSEURS EURECAT </div>