GB1585842A - Process for recovering molybdenum vanadium cobalt and nickel from roasted products of used catalysts from hydrotreatment desulphurization of petroleum - Google Patents

Description

(54) PROCESS FOR RECOVERING MOLYBDENUM. VANADIUM.

COBALT AND NICKEL FROM ROASTED PRODUCTS OF USED CATALYSTS FROM HYDROTREATMENT DESULPHURIZATION OF PETROLEUM (71) We, MARUBENI CORPORATION AND FUJI FINE CHEMICAL COM PANY LIMITED, both Japanese body corporates of 3-3. Hommachi, Higashi-ku, Osaka.

Japan and 1-1. Shinbashi 6-Chome, Minato-Ku, Tokyo. Japan. respectively do 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: This invention relates to a process for the separation of nickel and cobalt components from a solution containing ammonia nickel and cobalt complex ions, More particularly this invention relates to a process for recovering molybdenum. vanadium. cobalt and nickel from products obtained by oxidative roasting. at a temperature of from about 600"C to about 950"C. of used catalysts from the hydrotreatment desulfurization of petroleum.

A number of processes have been proposed for the leaching and separation of vanadium and molybdenum components from products containing said values obtained bv oxidative roasting of used catalysts such as used desulfuration catalysts of petroleum. Such roasted products normally contain ingredients such as nickel. cobalt and the like as well as aluminium derived from the carrier. It is thus difficult to leach and separate the vanadium and molybdenum values by a simple process with high leaching and separation efficiency.

Accordingly, such leaching and separation have not been put sucessfullv into practical use.

Such known proposals include processes wherein such used catalyst is subjected to oxidation calcination with an alkali such as caustic soda. sodium carbonate or the like under a fusion condition of the alkali and the resulting calcinated product is leached with an ammonia solution under pressure or with water. Such processes have a number of disadvantages such as it is difficult and inefficient to separate vanadium and molybdenum values from such calcinated products obtained under a fusing condition of the alkali in an oxidative atmosphere. there is a large amount of liquid to be treated. and stickv materials tend to form during the calcination. Hence such processes are not suitable for commercial application.Although. according to Japanese Patent Public Disclosure No. 11995/1975 for an improvement in oxidative calcination of a spent catalyst in co-fusion conditions with sodium sulfate. the disadvantageous formation of sticky material can be eliminated during such calcination. the poor separation efficiency cannot be avoided. In fact in this Disclosure. no separation of the vanadium component from the molybdenum component is carried out. In order to separate such components. it has been proposed in Published Japanese Patent Public Disclosure No. 2611/1975 to leach and separate such components by treating a liquor containing both of the components with an organic solvent comprising a light mineral oil containing a higher trialkvlamine and a water-immiscible monovalent higher alcohol at a pH of less than 1.5.Such a proposal has. however. a disadvantage in that it needs an organic solvent which is difficult to recover and. also. it is unsuitable for commercial practice from the viewpoint of environmental pollution. In addition it requires multiple leaching and separation and the separation efficiency is not satisfactory.

It has been known to separate nickel from cobalt each in the form of a solution containing the chlorocomplex ion as an analytical procedure. This procedure takes advantage of the fact that the chlorocomplexed nickel ion acts as a cation and the chlorocomplexed cobalt ion acts as an anion in a concentrated hydrochloric acid solution, and the chlorocomplexed cobalt ion is adsorbed selectively on an anion exchange resin to elute chlorocomplexed nickel ion and the adsorbed chlorocomplexed cobalt ion is eluted by using hydrochloric acid. However, this procedure has not been put into practical use in the commercial separation of nickel from cobalt, because the use of concentrated hydrochloric acid damages equipment and causes trouble in operations.

It is an object of our invention to provide a process for use in recovering valuable molybdenum, vanadium, cobalt and nickel from roasted products of used catalysts from hydrotreatment desulfurization of petroleum by simple chemical procedures in combination with the use of inexpensive chemicals.

It is another object of our invention to provide a process for use in separating an collecting a cobalt component and a nickel component respectively, from solids including the cobalt and nickel components and some aluminium component and the like by simple chemical procedures in combination with the use of inexpensive chemicals.

According to the present invention, there is provided a process for the separation of nickel and cobalt components from a solution containing ammonia nickel and cobalt complex ions which comprises: (a) oxidizing an aqueous solution containing ammonia complex ions of divalent nickel and cobalt with molecular oxygen or a molecular oxygen-containing gas to form selectively ammonia complex ions of trivalent cobalt; (b) subjecting the resulting solution to chromatography on a weakly acidic cation exchange resin, followed by eluting with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to elute selectively the ammonia nickel complex ions and then eluting the ammonia cobalt complex ions.

The invention includes a preferred process for recovering molybdenum, vanadium, cobalt and nickel from products obtained by oxidative roasting, at a temperature of from 600"C to about 950"C, of used catalysts from the hydrotreatment desulfurization of petroleum.

In this preferred process, the roasted products are subjected to hot water alkaline leaching. The resulting aqueous leaching solution containing most of the molybdenum and vanadium components and some aluminium component dissolved therein is separated from solids including most of the cobalt and nickel components and some aluminium component and the like. The resulting aqueous leaching solution may be further processed as in our copending application 32856/77 (Serial No. 1585841) to separate the molybdenum and vanadium components.

The solids including most of the cobalt and nickel components and some aluminium component and the like are subjected to hot water acid leaching. The resulting aqueous leaching solution is separated from the solid residue. The aqueous leaching solution is recycled to the hot water acid leaching to effect the hot water acid leaching to effect the hot water acid leaching of other solids including most of the cobalt and nickel components and some aluminium component. The leaching step is repeated more than once before removing the liquid. The leaching liquid after separation from the solids is oxidized with an oxidizing agent and neutralized with an alkali, thereby precipitating aluminium, vanadium and molybdenum hydroxides. The resulting precipitate above is filtered.Alternatively, molybdenum and vanadium components are separated by the use of a cation exchange resin, from nickel, cobalt and aluminium adsorbed thereon. An ammonium salt and ammonium hydroxide are added to the nickel and cobalt components to form an ammonia complex of divalent nickel and cobalt. The aqueous solution containing ammonia complex ions of divalent nickel and cobalt is oxidized with molecular oxygen or a molecular oxygen-containing gas to form selectively ammonia complex ions of trivalent cobalt. The resulting solution is contacted with a weakly acidic cation exchange resin to adsorb the ammonia complex ions thereon, followed by eluting with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to elute selectively the ammonia nickel complex ions and then eluting the ammonia cobalt complex ions.

In the accompanying drawings: Figure 1A is a schematic flow diagram illustrating the processing steps for effecting hot water alkaline leaching of roasted used catalysts from hydrotreatment desulfurization of petroleum, to separate and collect mother liquor containing most of the molybdenum component and some vanadium and aluminium components and solids including most of the cobalt and nickel components and some aluminium component, respectively, from the leaching liquid.

Figure 1B is a schematic flow diagram illustrating the processing steps for separating and collecting molybdenum and vanadium components respectively, from the- mother liquor containing most of the molybdenum component and some vanadium and aluminium components.

Figure 2 is a schematic flow diagram illustrating the processing steps for effecting hot water acid leaching of solids including most of the cobalt and nickel components and some aluminium component, to separate and collect a cobalt component and a nickel component respectively, from the leaching liquid.

The drawings illustrate a complete preferred process for recovering molybdenum.

vanadium, cobalt and nickel components from the used catalyst. which process includes the process of the invention.

The oxidative roasting of used hvdrotreatment desulfurization catalyst is carried out in the presence of molecular oxygen, normally in air to oxidize and burn carbonaceous organics and sulfur contained in the catalyst to remove them in the form of carbon dioxide and sulfur dioxide. It is preferred to effect simple oxidative roasting without adopting the co-fusion with an alkali as is done in conventional processes. The oxidative roasting is normally carried out at a temperature ranging from about 600 to about 950 C. The resulting oxidative roasted products contain normally vanadium and molvbdenum in the form of their oxides together with Co. Ni. Al components. It generally contains V in an amount ranging from about 10% to about 20%. Mo in an amount ranging from about 4% to about 8%.Co in an amount ranging from about to about 4% and Ni in an amount ranging from about 1% to about 2%.

In the process of the invention, the oxidative roasted product containing vanadium and molybdenum values is subjected to hot water alkaline leaching at a temperature of at least 50 C, preferably at a temperature of from 50 C to 100 C, more preferably at a temperature of from 55 C to 80 C in the presence of a caustic alkali, for example in the presence of caustic soda as shown in the extraction step (a). During the leaching, the leaching liquid system is adjusted so that the concentration of free caustic alkali contained therein is at least 1OCle by weight based on the weight of the leaching system. The upper limit of the concentration is not critical but the use of a higher concentration is economically disadvantageous to that the concentration range is preferably from 10% to 30%, more preferably from 10% 25%.If the concentration of the free caustic alkali is lower than about 10%, the deposition of an alkali salt of vanadium such as NaVO3 will become undesirably difficult in the later solid-liquid separation of the liquid phase containing vanadium and molybdenum values (step (c)) and the leaching efficiency will be decreased in the leaching of vanadium and molybdenum values from the oxidative roasted products. It is thus essential to effect the leaching under the condition that there exists the free caustic alkali in a concentration higher than about 10%.

The aqueous liquid obtained by the hot water alkali leaching and containing vanadium and molybdenum values is subjected to hot solid-liquid separation at a temperature higher than that for the substantial deposition of the vanadium and molyddenum values dissolved therein, for example at a temperature of from 10 to 100 C, preferably from 50 to 80 C and more preferably from 55 to 75 C to collect the liquid phase (step(b)). Such separation may be carried out by separating and collecting the liquid phase in said hot water alkaline leaching zone or by providing a separate separation zone. The solid phase including most Co and Ni components and some Al component. is removed from the system. Thevaluable Ni and Co values can be recovered from the solid phase by the undermentioned process.

Said vanadium value can be separated and collected as solids of an alkali salt such as NaX OR by solid-liquid separation of the liquid phase obtained by the preceding step at a temperature lower than that at which said vanadium value is deposited but showing substantially no molybdenum vaue as shown in the lower temperature solid-liquid separation step (c). In the lower temperature separation step. a temperature generally lower than 10 C. normally from 0'C to 400C is used.An alkali salt of vanadium can be easily precipitated out from the allialine liquid phase at a temperature lower than 40 C. whereas molybdenum is present in the form of an alkali salt. for example. in the form of Na.NtoO.

normally as its hydrate which does not substantially precipitate out at a temperature higher than about 0 C so that such a low temperature condition can be optionally selected and utilized. The precipitation of the molybdenum value also depends on the temperature, pH condition and the like in the system, but the optimum temperature can be easily determined by experimentation. Room temperature is used most conveniently but the separation can be carried out at a temperature lower than room temperature up to about 00C by force cooling the liquid phase.As a guide indication. it is preferred to select a temperature at which a minor amount of vanadium value remains in the mother liquor phase containing predominantl! molybdenum value after the separation but as little molvbdenum value as possible is entrained in the alkali salt of vanadium value separated from the mother liquor as solids. The solid phase comprises NaVO3 hydrate having a purity of about 85% or more.

more frequently a purity of about 90%, which may be recovered as crystals having a purity of higher than 99%, for example, a purity of 99.5% or higher by recrystallizing from an aqueous solution of a caustic alkali, for example an aqueous solution of caustic soda in a concentration from about 10 to about 30%. If desired, the recovered alkali vanadate may be subjected to double decomposition with an inorganic or organic ammonium salt to convert it to ammonium vanadate. Alternatively, the vanadate may be converted to vanadic acid by decomposing it with a mineral acid such as sulfuric acid or hydrochloric acid.

After such separation of the vanadium value, the resulting mother liquor contains predominantly the molybdenum value, which is then recycled to the hot water alkaline leaching step (a) to extract freshly added raw stock of roasted products. It is necessary to carry out the hot water alkaline leaching by keeping the above-specified free caustic alkalinity conditions. This may be done by replenishing optionally the caustic alkali and water correspondingly to the water removed from the system and the free caustic alkali consumed through the systems. Preferably, the caustic alkali and water or an aqueous caustic alkali may be replenished at any point after the low temperature separation step (c) and up to the repeat of the hot water alkaline leaching step (a). More generally, such a solution may be added into the recycling mother liquor or to the leaching zone.

The recycled leaching and separation operations are repeated under the condition that the amount of molybdenum value accumulated in the system by the recycled leaching does not exceed 7% by weight calculated as Mo and based on the weight of said liquid phase resulting from the hot separation step (b) and containing vanadium and molybdenum values by removing a portion of the mother liquor containing predominantly the accumulated molybdenum value. If the Mo content becomes higher than about 7%% by weight of the liquid phase containing the molybdenum value, the molybdenum value tends to contaminate the vanadium value precipitated during the low temperature separation step (c). Thus it is essential to control the Mo content under the specified condition.

The fluidity of the mother liquor containing strongly alkaline Mo, and some Al and V and having a pH higher than 13, normally higher than about 14, is adjusted, if necessary, by adding water and then subjecting to dealkalization by a non-neutralization. If the solution is neutralized by adding an acid or subjected to double decomposition by adding a water-soluble ammonium salt into the solution, V of high purity cannot be separated from the Mo with high efficiency in yields. Particularly, if the alkaline treatment is carried out by neutralization with a mineral acid or such treatment is omitted, the ammonium salt derived from the mineral acid used for the formation of solids containing the aluminium will be disadvantageously co-precipitated in the separation step of ammonium salts of molybdenum.It is thus necessary in the process of the invention to carry out the dealkalization of aqueous alkaline solution to be treated by a non-neutralization process. The dealkalization is carried out so that the pH of the resulting solution is higher than about 11 but less than 13.

If the dealkalization is carried out so that the pH of the resulting solution is less than about 11, for example of 10.5, the aluminium will be precipitated out during the dealkalization step to cause operational trouble. If the dealkalization is carried out insufficiently so the pH of the resulting solution is higher than 13. the resulting Mo and V values are contaminated with the co-produced salts as if the aqueous alkaline solution were subjected to direct double decomposition with an ammonium salt. Hence in the process of the invention the aqueous akaline solution is treated in a dealkalization process by a non-neutralization procedure so that the pH of the resulting solution is held within the narrow range between higher than 11 and less than 13, preferably from 11 to 12.

Such dealkalization may be carried out by any known non-neutralization process such as electrodialysis, or treatment through a cation exchange resin. After being subjected to non-neutralization dealkalization. a mineral acid such as sulfuric acid or hydrochloric acid is added to the resulting solution to adjust the pH of the solution to within from 7.5 to 9.5, preferably from 8 to 9. In commercial practice, it is preferred to use sulfuric acid. The aluminium in the solution is precipitated as aluminium-containing solids mainly in the form of aluminium hydroxide together with contaminants by pH adjustment. and the solids are then removed from the system. Such separation may be carried out at room temperature. If the pH is adjusted to a value lower than 7 or less by the addition of a mineral acid, V and/or Mo values are coprecipitated with the aluminium-containing solids. If the pH is higher than about 9.5. not enough of the aluminium-containing solids are precipitated. so that V and Mo values of high purity cannot be separated.

The resulting liquid phase obtained by the preceding pH adjustment contains V and Mo values but substantially no Al. It is then subjected to double decomposition with a water-soluble ammonium salt. The double decomposition may be performed simply by adding a water-soluble ammonium salt. Such a salt may be added in the form of a solution containing the salt. The ammonium salt is added preferably in an amount calculated as NH4+ of more than one mol of V value calculated as V, for example in an amount of I to 3 mols and in an amount of more than 2 mols per mol of Mo value calculated as Mo, for example in an amount of 2 to 3 mols. The double decomposition requires no heating, but if desired it can be performed under heating.

Water-soluble ammonium salts usable in the double decomposition include inorganic ammonium salts such as chloride, nitrate, sulfate and carbonate and organie.ammonium salts such as acetate and oxalate. In commerical practice, ammonium sulfate is preferably used. By the double decomposition, the V and Mo values present in the liquid phase as alkali vanadates and molybdates are converted to the ammonium salts. After the double decomposition, the precipitated ammonium vanadates, if necessary, are separated from the system by concentrating the liquid phase. The separation is carried out preferably at a temperature at which ammonium vanadates are selectively precipitated out but substantially no ammonium molybdates are precipitated.The separation is normally carried out at a temperature higher than about 40"C, for example from about 40"C to about 100"C, more preferably from about 50"C to about 80"C. Room temperature or less may be employed, but it is preferred to concentrate the mother liquor phase for the separation step of the molybdates in order to effect sufficiently the precipitation of the Mo value from the mother liquor phase so that the hot separation of vanadates is preferred commercially in order to reduce the heat loss.

The residual mother liquor after the separation of vanadates is then concentrated if necessary and cooled to room temperature or less, for example from about room temperature to about 0 C. The precipitated ammonium molybdates are separated.

The aforementioned solids including most of the Co and Ni components and some Al component are subjected to hot water acid leaching at a temperature of from 50"C to 100"C, in the presence of an acid such as sulfuric acid or hydrochloric acid, the concentration of the free acid in the leaching liquid being adjusted to a level of from 2% to 10%, preferably of from 4% to 6% by weight based on the weight of said leaching liquid. The resulting aqueous leaching solution containing Co, Ni and Al components and some Mo and V components is separated from solid residue.The aqueous leaching solution from the preceding step is recycled to the hot water acid leaching step to effect the hot water acid leaching of other solids including most of the Co and Ni components and some Al component as above, while maintaining the acid condition of said solution. The recycled leaching is repeated several times and said aqueous leaching solution is separated and optionally removed. -The leaching liquid is oxidized with an oxidizing agent such as H2O2, NaClO or KMnO4, and then it is neutralized with an alkali such as NaOH, KOH or NH40H to a pH of from 3.5 to 5.5, thereby precipitating Al V and Mo hydroxides. The resulting precipitate is filtered to obtain a solution containing Ni and Co components.Alternatively, Al V and Mo components which are included in said leaching liquid may be removed by the following procedure. The leaching solution is oxidized with an oxidizing agent such as H2O2, NaClO or KMnO4, and is neutralized with an alkali such as NaOH, KOH or NH40H to a pH of from 1 to 2, and then is passed through a cation exchange resin, thereby adsorbing Ni. Co and Al components. but not adsorbing Mo and V components. The adsorbed ingredients are eluted with 5% to 30% by weight of sulfuric acid or hydrochloric acid and then the elute is subjected to electrodialysis to adjust the pH to 1 to 2.The resulting liquid is neutralized with an alkali such as- NaOH, KOH or NH40H and the resulting precipitate of the- Al component is filered to obtain a solution containing Ni and Co components. When NH40H is used as a neutralizing agent, the addition of an ammonium salt in the following step may be omitted.

Such raw materials containing Ni and Co or those treated to remove contaminants therefrom are treated with an aqueous ammonium hydroxide solution containing an ammonium salt. for example, by dissolution or leaching to prepare easilv a solution of ammonia-complexed nickel and cobalt ions. Usable ammonium salts may include water-soluble inorganic ammonium salts such as sulfate, nitrate, chloride. carbonate and phosphate, and water-soluble organic ammonium salts such as acetate and oxalate.

Such an aqueous solution containing ammonia-complexed divalent nickel and cobalt is oxidized with molecular oxygen or a molecular oxygen-containing gas such as air. The oxidation may be performed by bubbling such a gas into the aqueous solution. As the oxidation proceeds at room temperature, heating or cooling is not required for the reaction.

but. if desired. the aqueous solution may be warmed or cooled. The oxidation will proceed if the aqueous solution containing ammonia-complexed divalent nickel and cobalt stands in air. and such spontaneous oxidation may be adopted. if desired. The oxidation of said ammonia complex ions proceeds selectively for converting the ammonia-complexed divalent cobalt to the ammonia-complexed trivalent cobalt.For example. ammoniacomplexed divalent cobalt [CO(NH,)"]2+ is selectively oxidized in an aqueous solution prepared by using an aqueous ammonia solution containing ammonium sulfate and having an pH higher than about 10 and containing ammonia-complexed divalent ions of Co(NH3)6 2+ and [Ni(NH3)612+ to trivalent complex ions of [Co(NH3)5 (112O)i3+ and/or Co(NH3)6 3+.

The solution subjected to such selective oxidation is then subjected to adsorption using a weakly acidic cation exchange resin adsorbent. The ammonia-complexed divalent nickel ion and trivalent cobalt ion are adsorbed on the adsorbent by such adsorption treatment.

However, more of the trivalent cobalt complex ion is adsorbed than of the divalent nickel complex ion due to the difference of their adsorption capacities. When the resulting adsorbent is eluted with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition, the divalent nickel complex ion is eluted selectively.

As a water-soluble ammonium salt, any one of the above-specified ammonium salts can be used. After the elution of divalent nickel complex ion, the adsorbent is eluted, for example, with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to obtain the ammonia-complexed trivalent cobalt ion. As a buffering solution containing a water-soluble ammonium salt, the above-mentioned aqueous ammonium hydroxide solution containing a water-soluble ammonium salt is also preferably used. The concentration of the water-soluble ammonium salt may be changed depending on the type of salt. Said ammonium salt may be used in a concentration ranging from 0.2 to 0.9 mols, more preferably from 0.4 to 0.7 mols calculated as ammonium ion. The pH of the aqueous solution should be from 8 to 12, more preferably from 9 to 11 and especially from 9.5 to 10.5.For the elution of the ammonia-complexed trivalent cobalt ion after the elution of the ammonia-complexed divalent nickel ion, a similar aqueous buffering solution containing a water-soluble ammonium salt may be used, preferably at a higher concentration that that for the elution of the divalent nickel complex ion, for example, within the range of from 0.7 to 2.5 mols of the ammonium ion of the ammonium salt.

Alternatively, the elution may be accomplished with an aqueous mineral acid, such as a 5% to 20%, preferably SCTo to 10%. by weight solution of sulphuric or hydrochloric acid. There is thus no special restriction on the solution for the elution of the trivalent cobalt complex ion and any solution which can elute the trivalent cobalt complex ion may be used. The elution may be performed at room temperature.

Nickel and cobalt values separated in the form of ammonia complex ions can be converted into the oxides or hydroxides by any conventional procedure, for example, by thermal decomposition. If desired, such complex ions may be converted to nickel sulfate and cobalt sulfate by any conventional procedure.

Embodiments of this invention are illustrated in detail in the following examples. It should be understood that this invention is, however, in no way limited by the examples, which are given only for the purpose of illustration of this invention.

Example 1 500 ml of an aqueous solution containing 5% by weight of H2SO4 and having a pH of 0.52 was added to the leaching residual (120 g) which Mo and V components were leached and separated from the used catalyst at about 15% of free NaOH in Example 1. and leached at 60"C for three hours under agitation. Immediately after the leaching. the reaction mixture was filtred. The filtrate had a pH of 0.82 and a temperature of 50 C, 50% H2SO4 and water was added to the filtrate to make 500 ml so that the resulting solution had a pH of 0.52 and the leaching was repeated using the made-up solution similarly to the foregoing procedure.

Table 1 shows the data obtained when such an leaching was repeated five times. The percent leaching of V, Mo. Co. Ni and Al was 6.12%, 4.88, 47.69%. 15.80% and 1.71%, respectively.

TABLE 1 V Mo Co Ni Al 1st leaching 0.19% 0.024% 0.36% 0.13% 0.23% 437 ml 0.83 g 0.10 g 1.57 g 0.57 g 1.01 g 2nd leaching 0.47% 0.13% 0.79% 0.24% 0.40% 484 ml 2.27 g 0.63 g 3.82 g 1.16 g 1.94 g 3rd leaching 0.87% 0.23% 1.19% 0.41% 0.67% 420 ml 3.65 g 0.97 g 5.00 g 1.72 g 2.81 g 4th leaching 1.03% 0.31% 1.51% 0.45% 0.80% 450 ml 4.65 g 1.38 g 6.81 g 2.03 g 3.60 g 5th leaching 1.27% 0.51% 1.84% 0.59% 1.16% 394 ml 5.00 g 2.01 g 7.25 g 2.32 g 4.57 g The 5th leaching liquid was oxidized with H202 and then neutralized with caustic soda to a pH of 1.5, followed by passing through a cation exchange resin. The adsorbed ingredients were eluted with 10% H2SO4. The composition of the elute is shown in Table 2.

TABLE 2 Elute: 400 mt V Mo Co Ni Al 0.05% Nil 1.27% 0.41% 0.80% 0.02 z Nil 5.08 g 1.64 g 3.20 g The elute was subjected to electrodialysis to adjust the pH to 1.5 and then neutralized with aqueous ammonia to bring the pH to 4.5. followed by filtering out the resulting precipitate of Al (OH)3. The composition of the filtrate is shown in Table 3.

TABLE 3 Filtrate: 415 m@ V Mo Co Ni Al Nil Nil 1.17% 0.37% Nil Nil Nil A.86 g 1.52 g Nil (NH4)2SO4 (27.4 g) and NHlOH in an amount sufficient to provide a pH of 10.5 was added to the filtrate. The resulting aqueous solution containing ammonia complexed divalent nickel and cobalt was then oxidized with air and the oxidized solution was then absorbed on a weakly acidic cation exchange resin. The absorbed ingredients were eluted with an aqueous alkaline solution containing 0.25 mols of (NH4)2SO4 and NH4OH sufficient to provide a pH of about 10 to elute initially a solution containing nickel. The solution was replaced by 5% H2SO4 at this stage to elute a solution containing cobalt exclusively.The compositions of each solution are shown in Table 4.

TABLE 4 Co Ni Nickel solution 0.0002% 0.07% 2000 ml 0.004 g 1.48 g Cobalt solution 0.82% 0.002% 550 ml 4.53 g 0.01 g An aqueous solution of 10% caustic soda was then added to the respective resulting solutions of Co and Ni, and then they were decomposed under heating. The oxides or hydroxides obtained by the thermal decomposition were dissolved in dilute hydrochloric acid; then sulfuric acid was added and the resulting solution was concentrated to give cobalt sulfate and nickel sulfate.

The percent recovery of Ni and Co from the leaching liquid was 63.79% and 62.48%, respectively.

The percent recovery of Ni and Co from the used catalyst was 10.17% and 29.75%, respectively.

Example 2 A used catalyst from the direct desulfurization of petroleum was roasted at 800 C in an oxidative atmosphere. The roasted product had a composition as shown in Table 5.

TABLE 5 V (to) Mo () Co (%) Ni (%) Al (%) 13.3 6.5 0.72 3.4 3'.4 To the roasted product (150 g) was added 15% aqueous solution of NaOH, 500 ml of an aqueous solution containing 5% by weight of H2SO4 and having a pH of 0.52 was added to the alkaline leaching residual (120 g) and leached at 60 C for three hours under agitation.

Immediately after the leaching, the reaction mixture was filtered. The filtrate had a pH of 0.82 and a temperature of 50 C, 50% H2SO4 and water was added to the filtrate to make 500 ml, so that the resulting solution had a pH of 0.52 and the leaching was repeated using the made-up solution similarly to the foregoing procedure. Table 6 shows the data obtained when such an leaching was repeated three times.

TABLE 6 V Mo Co Ni Al 1st leaching 0.29% 0.10% 0.84% 0.18% 0.03% 500 m@ 1.45 Q 0.5 g 0.4' Q 0.9 Q 0.17 g 2nd leaching 0.65% 0.24% 0.19% 0.29% 0.07% 526 m@ 3.42 g 1.25 g 1.0 g 1.53 g 0.37 g 3rd leaching 1.02% 0.40% 0.25% 0.42% 0.13% 580 m@ 5.92 g 2.32 g 1.45 g 2.44 g 0.76 g The percent leaching of V. Mo. Co. Ni and Al was 9.89%. 7.93%. 44.75%. 15.95% and 0.52% respectively.

The 3rd leaching liquid was oxidized with H2O2 and then neutralized with an aqueous ammonia solution to a pH of 4.9. thereby to precipotate Al and some Mo and Co hydroxides. The resulting precipitate was filtered. The composition of the filtrate is shown in Table 7.

TABLE 7 Filtrate: 620 m( V Mo Co Ni Al 0.28% 0.7% 0.19% 0.36% Nil 1.72 g 0.4 g 1.17 g 2.22 a Nil An aqueous ammonia solution was added to the filtrate as indicated in Table 1S to adjust the pH to 10. thereby forming ammonia complexed divalent Ni and Co. After being oxidized with air. the oxidized solution was contacted with a weakly acidic cation exchange resin. V and Mo components are not adsorbed on the weakly acidic cation exchange resin.

The absorbed ingredients were eluted with an aqueous alkaline solution containing 0.25 mol of (NH4)2SO4 and NH4OH (pH : about 10) to elute initially a solution containing Ni.

The solution was replaced by 5% HnSO4 at this stage to elute a solution containing Co exclusively. The composition of each solution are shown in Table S.

TABLE S Co Ni Ni solution 0.0004% 0.07% 3000 ml 0.001 o 2.05 g Co solution 0.18% 0.008% 500 ml 0.92 g 0.004 g The percent recovery of Ni and Co from the leaching liquid was 84.0% and 63.4%, respectively.

The percent recovery of Ni and Co from the used catalyst was 13.4% and 28.4%.

respectively.

Comparative Example The alkaline leaching residual as shown in Example 1 was subjected to single acid leaching with 1% H2SO4, respectively. Table 9 shows results obtained together data obtained with a solution containing 2.5%. 5%. 7.5% and 10% H2SO4 in accordance with the present invention for facilitating comparison.

TABLE 9 V Mo Co Ni Al 10% H2SO4 0.20% 0.022% 0.33% 0.14% 0.25% (Subject Invention) 1.02 g 0.11 g 1.68 g 0.72 g 1.25 g 7.5% H2SO4 0.17% 0.023% 0.31% 0.13% 0.22% (Subject Invention) 0.94 g 0.13 g 1.68 g 0.72 g 1.21 g 5% H2SO4 0.14% 0.017% 0.30% 0.11% 0.17% (Subject Invention) 0.78 g 0.095 g 1.68 g 0.62 g 0.95 g 2.5% H2SO4 0.06% 0.007% 0.26% 0.09% 0.14% (Subject Invention) 0.37 g 0.044 g 1.62 g 0.57 g 0.88 g 1% H2SO4 6.0009% 0.0005% 0.27% 0.08% 0.03% (Comparative Example) 0.005 g 0.003 g 1.52 g 0.44 g 0.19 g TABLE 10 The percent leaching at 5% H2SO4 V Mo Co Ni Al 4.8 1.1 55.17 21.3 1.8 WHAT WE CLAIM IS: 1.A process for the separation of nickel and cobalt components from a solution containing ammonia nickel and cobalt complex ions which comprises: (a) oxidizing an aqueous solution containing ammonia complex ions of divalent nickel and cobalt with molecular oxygen or a molecular oxygen-containing gas to form selectively ammonia complex ions of trivalent cobalt; (b) subjecting the resulting solution to chromatography on a weakly acidic cation exchange resin, followed bv eluting with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to elute selectively the ammonia nickel complex ions and then eluting the ammonia cobalt complex ions.

2. A process for recovering molybdenum, vanadium. cobalt and nickel from products obtained by oxidative roasting, at a temperature of from 600 C to 950"C. of used catalysts from the hydrotreatment desulfurization of petroleum. which comprises: (a) subjecting said roasted products to hot water alkaline leaching at a temperature of from 50"C to 1000C in the presence of a caustic alkali. the amount of the free caustic alkali in the leaching liquid being adjusted to a level of from 10% to 30wiz by weight based on the weight of said leaching liquid: : (b) separating the resulting aqueous leaching solution containing almost all of the molybdenum and vanadium components and some aluminium component dissolved therein from solids including almost all of the cobalt and nickel components and some aluminium component at a temperature of from 50"C to 80"C so as not to result in substantial deposition of the vanadium and molybdenum components; (c) subjecting the solids from said step (b) to hot water acid leaching at a temperature of from 50"C to 1000C in the presence of sulfuric acid or hydrochloric acid. the concentration of the free acid in the leaching liquid being adjusted to a level of from

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (29)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   TABLE 9 V Mo Co Ni Al 10% H2SO4 0.20% 0.022% 0.33% 0.14% 0.25% (Subject Invention) 1.02 g 0.11 g 1.68 g 0.72 g 1.25 g 7.5% H2SO4 0.17% 0.023% 0.31% 0.13% 0.22% (Subject Invention) 0.94 g 0.13 g 1.68 g 0.72 g 1.21 g 5% H2SO4 0.14% 0.017% 0.30% 0.11% 0.17% (Subject Invention) 0.78 g 0.095 g 1.68 g 0.62 g 0.95 g

   2.5% H2SO4 0.06% 0.007% 0.26% 0.09% 0.14% (Subject Invention) 0.37 g 0.044 g 1.62 g 0.57 g 0.88 g 1% H2SO4 6.0009% 0.0005% 0.27% 0.08% 0.03% (Comparative Example) 0.005 g 0.003 g 1.52 g 0.44 g 0.19 g TABLE 10 The percent leaching at 5% H2SO4 V Mo Co Ni Al

   4.8 1.1 55.17 21.3 1.8 WHAT WE CLAIM IS: 1.A process for the separation of nickel and cobalt components from a solution containing ammonia nickel and cobalt complex ions which comprises: (a) oxidizing an aqueous solution containing ammonia complex ions of divalent nickel and cobalt with molecular oxygen or a molecular oxygen-containing gas to form selectively ammonia complex ions of trivalent cobalt; (b) subjecting the resulting solution to chromatography on a weakly acidic cation exchange resin, followed bv eluting with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to elute selectively the ammonia nickel complex ions and then eluting the ammonia cobalt complex ions.

   2. A process for recovering molybdenum, vanadium. cobalt and nickel from products obtained by oxidative roasting, at a temperature of from 600 C to 950"C. of used catalysts from the hydrotreatment desulfurization of petroleum. which comprises: (a) subjecting said roasted products to hot water alkaline leaching at a temperature of from 50"C to 1000C in the presence of a caustic alkali. the amount of the free caustic alkali in the leaching liquid being adjusted to a level of from 10% to 30wiz by weight based on the weight of said leaching liquid:: (b) separating the resulting aqueous leaching solution containing almost all of the molybdenum and vanadium components and some aluminium component dissolved therein from solids including almost all of the cobalt and nickel components and some aluminium component at a temperature of from 50"C to 80"C so as not to result in substantial deposition of the vanadium and molybdenum components; (c) subjecting the solids from said step (b) to hot water acid leaching at a temperature of from 50"C to 1000C in the presence of sulfuric acid or hydrochloric acid. the concentration of the free acid in the leaching liquid being adjusted to a level of from
2. 2% to 10% by weight based on the weight of said leaching liquid; (d) separating the resulting aqueous leaching solution containing cobalt. nickel and aluminium components, and some molybdenum and vanadium components from solid residue; (e) recycling the aqueous leaching solution from said step (d) to the hot water acid leaching in said step (c) to effect the hot water acid leaching Qf other solids from said step (b) while maintaining the acid condition of said solution; (f) repeating the recycled leaching more than once and separating said leaching, liquid; (g) oxidizing the leaching liquid with an oxidizing agent, then neutralizing it with an alkali to a pH of from 3.5 to 5.5, thereby precipitating aluminium, vanadium and molybdenum hydroxides;; (h) filtering the resulting precipitate of aluminium. vanadium and mofybdenum hydroxides; (i) adding an ammonium salt and ammonium hydroxide to the filtrate from the step (h) to adjust the pH to from 9 to 11. thereby forming ammonia complexed divalent nickel and cobalt; and separating nickel and cobalt components in accordance with claim l bv (j) oxidizing the aqueous solution containing ammonia complex ions of divalent nickel and cobalt with molecular oxygen or a molecular oxygen-containing gas to form selectively ammonia complex ions of tnvalent cobalt.

   (k) contacting the resulting solution with a weakly acidic cation exchange resin to adsorb the ammonia complex ions thereon, followed by eluting with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to elute selectively the ammonia nickel complex ions and then eluting the ammonia cobalt complex ions.
3. 3. A process as claimed in claim 2 wherein said hot water alkaline leaching in said step (a) is carried out at a temperature of from O C to 80 C.
4. 4. A process as claimed in claim 2 or claim 3 wherein said hot solid-liquid separation in said step (b) is carried out at a temperature of from 55 C to 75 C.
5. 5. A process as claimed in any one of claims 2 to 4 wherein the concentration of the free acid in the leaching liquid in said step (c) is adjusted to a level of from 4% to 6Cc bv weight based on the weight of said leaching liquid.
6. 6. A process as claimed in any one of claims 7 to 5 wherein the oxidizing agent used in the step (g) is selected from H2O2. NaClO and KMnO4.
7. 7. A process as claimed in any one of claims 7 to 6 wherein the alkali used in the step (g) is selected from sodium hydroxide. potassium hydroxide and ammonium hydroxide.

   -
8. 8. A process as claimed in any one of claims 1 to 7 wherein the ammonium salt used in the step (i) is selected from ammonium sulfate. ammonium nitrate, ammonium chloride.

   ammonium carbonate. ammonium acetate and ammonium oxalate.
9. 9. A process as claimed in any one of claims 2 to 8 wherein the pH of the filtrate in the step (i) is adjusted to from 9.5 to 10.5.
10. 10. A process as claimed in any one of claims 2 to 9 wherein the water-soluble ammonium salt used in the step (k) is selected from ammonium sulfate. ammonium nitrate.

    ammonium chloride. ammonium carbonate. ammonium' phosphate. ammonium acetate and ammonium oxalate.
11. 11. A process as claimed in any one of claims 2 to 10 wherein the concentration of the water-soluble ammonium salt used to elute the ammonium nickel complex in the step (k) is from 0.4 mol to 0.7 mol as NH4t and the pH of the buffering solution therein is from 9, to 11.
12. 12. A-process as claimed in any one of claims 7 to 11 wherein the concentration of the water-soluble ammonium salt used to elute the ammonium cobalt complex in the step (k) is from 0.7 mol to 2.5 mols as NH4
13. 13.A process as claimed in any one of claims 7 to 12 wherein the elute for the elution of the ammonium cobalt complex from the weaklv acidic cation exchange resin in the step (k) is aqueous sulfuric acid or hydrochloric acid solution. the concentraino of the sulphuric acid or hydrochloric acid being from 5% to '0T by weight based on the weight of the eluting solution.
14. 14. A process as claimed in claim 13 wherein the concentration of the elute is from said to 10% by weight.
15. 15. A process for recovering molybdenum vanadium, cobalt and nickel from products obtained by oxidative roasting, at a temperature of from 600 C to 950 C, of used catalysts from the hydrotreatment desulfurization of petroleum, which comprises: (a) subjecting said roasted products to hot water alkaline leaching at a temperature of from 50 C to 100 C in the presence of a caustic alkali, the amount of the free caustic alkali in the leaching liquid being adjusted to a level of from 10% to 30% by weight based on the weight of said leaching liquid;; (b) separating the resulting aqueous leaching solution containing almost all of the molybdenum and vanadium components and some aluminium component dissolved therein from solids including almost all of the cobalt and nickel components and some aluminium component at a temperature of from 50 C to 80 C so as not to result in substantial deposition of the vanadium and molybdenum components: (c) subjecting the solids from said step (b) to hot water acid leaching at a temperature of from 50 C to 100 C in the presence of sulfuric acid or hydrochloric acid, the concentration of the free acid in the leaching liquid being adjusted to a level,of from 2% to 10% by weight based on the weight of said leaching liquid:: (d) separating the resulting aqueous leaching solution containing cobalt, nickel and aluminium components, and some molybdenum and vanadium components from solid residue; (e) recycling the aqueous leaching solution from said step (d) to the hot water acid leaching in said step (c) to effect the hot water acid leaching of other solids from said step (b) while maintaining the acid condition of said solution (f) repeating the recycled leaching more than once and separating said leaching liquid: (g) oxidizing the leaching liquid with an oxidizing agent, then neutralizing it, with an alkali to a pH of from 1 to 2 and passing it through a cation exchange resin, thereby adsorbing nickel, cobalt and aluminium components, but not adsorbing molybde num and vanadium components:: (h) eluting the adsorbed ingredients with 5% to, 30% by weight of sulfuric acid or hydrochloric acid and then subjecting the elute to electrodialysis to adjust the pH to from 1 to 2: (i) neutralizing the resulting liquid from the step (h) with an alkali and filtering the resulting precipitate of aluminium hydroxide: (j) adding an ammonium salt and ammonium hydroxide to the filtrate from step (i) to adjust the pH to from 9 to 11. thereby forming ammonia complexed divalent nickel and cobalt: and separating nickel and cobalt components in accordance with claim 1 bv (k) oxidizing the aqueous solution containing ammonia complex ions of divalent nickel and cobalt with molecular oxygen or a molecular oxygen-containing gas to fonn selectively ammonia complex ions of tn'valent cobalt: (I) contacting the resulting solution with a weakly acidic cation exchange resin to adsorb the ammonia complex ions thereon. followed by doting with a buffering solution containing a water-soluble ammonium salt under an ammonia alkaline condition to elute 'selectively the ammonia nickel complex ions and then eluting the ammonia cobalt complex ions.
16. 16. A process as claimed in claim 15 wherein said hot water alkaline leaching in said step (a) is carried our at a temperature of from 55 C to 80 C.
17. 17. A process as claimed in claim 15 or claim 16 wherein said hot solid-liquid separation in said step (b) is carried out at a temperature of from 55-C to 75ec
18. 18. A process as claimed in any one of claims 15 to 17 wherein the concentration of the free acid in the leaching liquid in said step (c) is adjusted to a level of from 4% to 6% by weight based on the weight of said leaching liquid.
19. 19. A process as claimed in any one of claims 15 to 18 wherein the oxidizing agent used in the step (p) is selected from the group consisting of H2O2. NaCIO and liMnO,
20. 20. A process as claimed in any one of claims 15 to 19 wherein the alkali used in the step (g) is selected from sodium hydroxide, potassium hydroxide and ammonium hydroxide.
21. 21. A process as claimed in any one of claims 15 to 20 wherein the ammonium salt used in the step (j) is selected from ammonium sulfate, ammonium nitrate, ammonium chloride, ammonium carbonate, ammonium acetate and ammonium oxalate.
22. 22. A process as claimed in any one of claims 15 to 21 wherein the alkali used in the step (i) is selected from sodium hydroxide, potassium hydroxide and ammonium hydroxide.
23. 23. A process as claimed in any one of claims 15 to 22 wherein the pH of the filtrate in the step (j) is adjusted to from 9.5 to 10.5.
24. 24. A process as claimed in any one of claims 15 to 't wherein the water-soluble ammonium salt used in the step (1) is selected from amnionium sulfate. ammonium nitrate ammonium chloride. ammonium carbonate ammonium phosphate. aminonium acetate and ammonium oxalate.
25. 25. A process as claimed in any one of claims 15 to 24 wherein the concentration of the water-soluble ammonium salt used to elute the ammonium nickel complex in the step (1) is from 0.4 mol to 0.7 mol as NH2 and the pH of the buffering solution therein is from 9 to 11.
26. 26. A process as claimed in any one of claims 15 to 25 wherein the concentration of the water-soluble ammonium salt used to elute the ammonium cobalt complex in the step (1) is from 0.7 mol to 2.5 mols as NH4+.
27. 27. A process as claimed in any one of claims 15 to 26 wherein the elute for the elution of the ammonium cobalt complex from the weakly acidic cation exchange resin in the step (l) is aqueous sulfuric acid or hydrochloric acid solution from 5% to 20% by weight based on the weight of the eluting solution.
28. 28. A process as claimed in claim 27 wherein the concentration of the elute is from 5% to 10% by weight.
29. 29. A process for recovering cobalt and nickel from roasted products of used catalysts from hydrotreatment desulphurization of petroleum, substantially as hereinbefore described with reference to Example 1 or Example 2.