KR102539557B1 - Recovery method of valuable metal from waste of desulfurization catalyst - Google Patents

Abstract

In the method for recovering valuable metals from the spent desulfurization catalyst of the present invention, the spent desulfurization catalyst is washed with a hydrocarbon-based solvent. The cleaned spent desulfurization catalyst is roasted in an oxidizing atmosphere. Valuable metals are leached from the roasted spent desulfurization catalyst. High-purity valuable metals can be recovered with high efficiency.

Description

Valuable metal recovery method of waste desulfurization catalyst {RECOVERY METHOD OF VALUABLE METAL FROM WASTE OF DESULFURIZATION CATALYST}

The present invention relates to a method for recovering valuable metals from spent desulfurization catalysts. More specifically, it relates to a method for recovering valuable metals from spent desulfurization catalysts using a leaching method.

Petroleum-based fuels containing sulfur components generate SO _x upon combustion. The generated SO _x is discharged and serves as a major cause of air pollution.

In addition, since sulfur component accelerates metal corrosion, fuel containing sulfur component shortens the lifespan of metal fuel tanks, fuel pipes, internal combustion engines, and the like.

Therefore, it is necessary to remove sulfur in crude oil in an oil refining process. Through the desulfurization process, sulfur, nitrogen, and metal compounds contained in Sungkyu products are removed. A desulfurization catalyst is used in the desulfurization process, and the performance of the desulfurization catalyst gradually decreases during the course of the desulfurization process.

The performance of the desulfurization catalyst with reduced performance may be restored through regeneration treatment so that it can be reused, but the function of the catalyst may be substantially permanently lost after several regeneration treatments. Catalysts that have permanently lost their function can usually be disposed of.

Since the waste catalyst contains various precious metals, when the precious metal is separated from the waste catalyst, the desulfurization catalyst can be reproduced through this, and thus the economic feasibility is greatly increased. In addition, recycling of spent catalysts can improve the efficiency of resource use and is also environmentally desirable.

For example, Korean Patent Registration No. 10-0700348 discloses a method for recovering molybdenum oxide by heating, sublimating, and cooling a spent desulfurization catalyst, but improvements in the purity, recovery rate, and energy efficiency of the process of valuable metals are disclosed. additionally required.

Korean Registered Patent Publication No. 10-0700348

One object of the present invention is to provide a method for recovering valuable metals from a spent desulfurization catalyst having excellent recovery rate and efficiency.

1. Washing spent desulfurization catalyst obtained from a desulfurization process including at least one of heavy oil desulfurization, light oil desulfurization, naphtha desulfurization, catalytic cracking, heavy oil catalytic cracking, or vacuum residue desulfurization waste with a hydrocarbon-based solvent; Roasting the cleaned spent desulfurization catalyst in an oxidizing atmosphere; and leaching valuable metals from the roasted spent desulfurization catalyst.

2. The method for recovering valuable metals from a spent desulfurization catalyst according to 1 above, wherein the hydrocarbon-based solvent includes kerosene.

3. The method for recovering valuable metals from the spent desulfurization catalyst according to 1 above, further comprising drying the spent desulfurization catalyst washed before roasting.

4. The method for recovering valuable metals from a spent desulfurization catalyst according to 3 above, wherein the drying is performed at 60 to 100 ° C.

5. The method for recovering valuable metals from a spent desulfurization catalyst according to 1 above, wherein the roasting is performed at 300 to 550 ° C.

6. The method for recovering valuable metals from a spent desulfurization catalyst according to 1 above, wherein the oxidizing atmosphere includes an oxidizing gas including oxygen and nitrogen.

7. The method for recovering valuable metals from a spent desulfurization catalyst according to 6 above, wherein the volume ratio of oxygen and nitrogen in the oxidizing gas is 3:7 to 5:5.

8. The method for recovering valuable metals from a spent desulfurization catalyst according to 6 above, wherein the roasting is performed while continuously supplying the oxidizing gas.

9. The method for recovering valuable metals from a spent desulfurization catalyst according to 8 above, wherein the flow rate of the oxidizing gas is 25 to 50 L/min.

10. The method for recovering valuable metals from the spent desulfurization catalyst according to 1 above, wherein less than 1% by weight of carbon relative to the carbon content of the spent desulfurization catalyst is leached out.

11. The method for recovering valuable metals from a spent desulfurization catalyst according to 1 above, further comprising recovering the leached valuable metals.

12. The method for recovering valuable metals from a spent desulfurization catalyst according to 12 above, wherein in the step of recovering the leached valuable metals, an extraction solution containing at least one of an ammonium-based compound and an ionic liquid is used.

13. The method for recovering valuable metals from a spent desulfurization catalyst according to 12 above, wherein vanadium and molybdenum contained in the extraction solution are recovered in the form of V ₂ O ₅ and CaMoO ₄ , respectively.

According to exemplary embodiments, valuable metals such as nickel, molybdenum, and vanadium can be recovered with high purity and efficiency by using a leaching method after washing the spent desulfurization catalyst with a hydrocarbon-based solvent and roasting it in an oxidizing atmosphere.

For example, hydrocarbon impurities in the spent desulfurization catalyst can be effectively removed by kerosene cleaning, and kerosene used for cleaning can be reused.

In addition, the content of organic impurities containing carbon, hydrogen, nitrogen and sulfur can be effectively reduced by oxidative roasting.

Oxidative roasting may be performed at a temperature of 550° C. or less to suppress generation of SOx.

1 and 2 are schematic flowcharts illustrating a method for recovering valuable metals from a spent desulfurization catalyst according to exemplary embodiments.
3 is an IR spectrum of the spent desulfurization catalyst before cleaning.
4 is an IR spectrum of the spent desulfurization catalyst before roasting after washing.
5 is an IR spectrum of a spent desulfurization catalyst after roasting.
6 is a photograph of a spent desulfurization catalyst before cleaning.
7 to 10 are photographs of spent desulfurization catalysts after washing and roasting.

In exemplary embodiments of the present invention, waste desulfurization catalysts including at least one of heavy oil desulfurization, light oil desulfurization, naphtha desulfurization, catalytic cracking, heavy oil catalytic cracking, or vacuum residue desulfurization wastes are washed with a hydrocarbon-based solvent and cleaned. Provided is a method for recovering valuable metals from a spent desulfurization catalyst in which the spent desulfurization catalyst is roasted in an oxidizing atmosphere and then valuable metals are leached from the roasted spent desulfurization catalyst. High-purity valuable metals can be recovered with high efficiency.

Referring to the following drawings, the embodiment of the present invention will be described in more detail. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the contents of the above-described invention, so the present invention is described in such drawings should not be construed as limited to

1 is a schematic flowchart illustrating a method for recovering valuable metals from a spent desulfurization catalyst according to exemplary embodiments.

Referring to FIG. 1, the spent desulfurization catalyst may be washed with a hydrocarbon-based solvent (eg, step S10).

As used herein, the term 'spent desulfurization catalyst' may refer to a catalyst whose catalytic activity is reduced because it is used in a desulfurization process during a crude oil refining process. The desulfurization process is, for example, heavy oil desulfurization (RHDS), diesel desulfurization, naphtha desulfurization, catalytic cracking, heavy oil catalytic cracking or reduced pressure It may include at least one of residual oil desulfurization (Vacuum Residue Desulfurization: VRDS).

For example, the spent desulfurization catalyst may be one in which valuable metals such as nickel (Ni), molybdenum (Mo), and vanadium (V) are supported on an aluminum carrier. The spent desulfurization catalyst may further include organic impurities adsorbed or aggregated to the spent desulfurization catalyst during the desulfurization process. The organic impurities may mean, for example, compounds containing elements such as carbon, hydrogen, nitrogen, and sulfur bound to the spent desulfurization catalyst.

According to exemplary embodiments, the organic impurities may be removed from the spent desulfurization catalyst and the valuable metal may be effectively recovered.

In example embodiments, the hydrocarbon-based solvent may include a compound composed of carbon and hydrogen and a mixture thereof. In some embodiments, the hydrocarbon-based solvent may include compounds consisting essentially of only carbon and hydrogen.

The hydrocarbon-based solvent can effectively remove hydrocarbon impurities contained in the spent desulfurization catalyst.

In example embodiments, the hydrocarbon-based solvent may include kerosene. In this case, the cleaning power of the hydrocarbon impurities can be remarkably improved. In addition, kerosene can be repeatedly reused in the cleaning process, or recycled as fuel, for example, after the cleaning process.

For example, during the cleaning, the hydrocarbon-based solvent may be used in a weight ratio of 1:1 to 5:1 with respect to the spent desulfurization catalyst. When the amount of the hydrocarbon-based solvent used is less than the aforementioned range, the hydrocarbon-based impurities may not be sufficiently removed from the spent catalyst. When the amount of the hydrocarbon-based solvent exceeds the above-described range, the cleaning power for the hydrocarbon-based impurities is substantially saturated, and thus the economic efficiency of the process may be reduced. Preferably, the hydrocarbon-based solvent may be used in a weight ratio of 1.5:1 to 3:1 with respect to the spent desulfurization catalyst.

In some embodiments, the spent desulfurization catalyst may not be pulverized before washing and roasting. By not pulverizing the spent desulfurization catalyst before roasting, further transformation and utilization of the spent desulfurization catalyst can be improved. For example, the particle size of the spent desulfurization catalyst may be 1 to 5 mm.

The washed spent desulfurization catalyst may be roasted in an oxidizing atmosphere (eg, step S20).

The oxidizing atmosphere may include conditions exposed to oxygen. The oxidizing atmosphere may include air or an oxidizing gas including oxygen. For example, the oxidizing atmosphere may be formed by replacing the internal gas of the reaction chamber with air or the oxidizing gas. The oxidizing gas may further include nitrogen.

Valuable metals contained in the spent desulfurization catalyst may be oxidized and converted into metal oxides by the roasting. For example, nickel oxide, molybdenum oxide, vanadium oxide, and the like may be formed by the roasting.

In some embodiments, a single oxide of a valuable metal may be formed by the roasting. For example, the single metal oxide may include only one kind of the valuable metal. The single metal oxide can be recovered as the valuable metal with high purity and high efficiency through a leaching process.

In addition, the organic impurities may be removed from the spent desulfurization catalyst by the roasting.

In exemplary embodiments, the roasting may be performed at a temperature of 300 to 550°C. When the roasting temperature is lower than 300° C., the valuable metal may not be converted into the metal oxide form or the organic impurities may be insufficiently removed. When the roasting temperature is higher than 550° C., a composite metal oxide or metal oxide composite further including two or more types of valuable metals or one type of valuable metal and an additional metal may be formed. The composite metal oxide or the metal oxide composite may have a low recovery rate of valuable metals through a leaching process. In addition, during high-temperature roasting, SOx and NOx are formed from sulfur or nitrogen, which can pollute the environment.

Preferably, the roasting temperature may be 350 to 450 °C. At 450° C., the conversion to the single metal oxide can be substantially completed, thereby increasing the energy efficiency of the process.

In example embodiments, the volume ratio of oxygen and nitrogen in the oxidizing gas may be 3:7 to 5:5.

When the ratio of oxygen is less than the above range, removal of the organic impurities and conversion into the single metal oxide may be insufficiently performed. Therefore, the leaching rate of the valuable metal may decrease in the leaching process.

Conversely, when the ratio of oxygen exceeds the above range, the reaction temperature and removal of the product may become difficult as the roasting reaction occurs vigorously. For example, as the reaction temperature excessively increases, the composite metal oxide or metal oxide composite may be formed instead of the single metal oxide. In addition, excessive side reactions of active oxygen radicals with metals and residual organic solvents may occur, and harmful gases containing Ni, V, Mo, Al, Si, SOx, or NOx may be excessively discharged.

In exemplary embodiments, the roasting may be performed in a state in which the reaction chamber is substituted with the oxidizing gas. In addition, the oxidizing gas may be continuously supplied to the reaction chamber during the roasting process. In this case, oxygen necessary for removing the organic impurities and converting them into the single metal oxide may be continuously supplied. Accordingly, the removal rate of organic impurities and the conversion rate to a single metal oxide can be increased.

In exemplary embodiments, the supply flow rate of the oxidizing gas may be 25 to 50 L/min. When the flow rate is less than 25 L/min, the conversion rate to the single metal oxide and the leaching rate of the valuable metal may decrease. Also, the removal rate of the organic impurities may decrease. When the flow rate exceeds 50 L/min, it is difficult to control the conversion of a single metal oxide by process design, excessive oxygen is supplied, resulting in excessive combustion of metals and organic solvents, adversely affecting the purity of metals, The structure may be destroyed.

The valuable metal may be leached from the roasted spent desulfurization catalyst (eg, step S30). For example, valuable metals converted into oxides in the roasting process may be extracted into a solution in the leaching process.

The leaching may be performed by an acidic leaching process using sulfuric acid, hydrochloric acid, nitric acid, and an acidic solution in which these are mixed. In addition, the leaching may be performed in a basic dance process using a basic solution. The basic solution may include an aqueous solution such as sodium hydroxide or ammonium hydroxide.

In the leaching process, additional oxidizing agents or oxidizing aids such as, for example, oxygen, manganese oxide, perchloric acid, etc. may be used. The additional oxidizing agent and the oxidizing auxiliary may additionally convert the valuable metals of the spent desulfurization catalyst into the single metal oxide form. The single metal oxide can be effectively leached by the leaching process.

2 is a schematic flowchart illustrating a method for recovering valuable metals from a spent desulfurization catalyst according to exemplary embodiments.

Referring to FIG. 2 , the spent desulfurization catalyst cleaned before roasting may be dried (eg, step S15).

The hydrocarbon-based solvent adsorbed to the spent desulfurization catalyst in the washing process may be at least partially removed by the drying. In this case, the valuable metals contained in the spent desulfurization catalyst may be effectively converted into the single metal oxide during the roasting process.

In exemplary embodiments, the drying may be performed at a temperature of 60 to 100 °C. Within the above temperature range, it is possible to effectively remove the hydrocarbon-based solvent and hydrocarbon impurities dissolved in the hydrocarbon-based solvent without side reactions. In terms of removal efficiency and speed, the drying is preferably performed at a temperature of 70 to 90 ° C.

In example embodiments, the leached valuable metal may be recovered (eg, step S40).

In some exemplary embodiments, in the step of recovering the leached valuable metal, an extraction solution containing an ammonium-based compound or an ionic liquid may be used. In addition, the pH of the extraction solution may be maintained at about 5. Organic acids such as ascorbic acid and/or inorganic acids such as hydrochloric acid may be used to adjust the pH of the extraction solution.

In addition, extraction of vanadium and molybdenum is induced by the ammonium-based compound included in the extraction solution. From the standpoint of being able to promote the extraction of vanadium and molybdenum, the ammonium-based compound may be a quaternary ammonium salt.

In addition, in some exemplary embodiments, as a preferred example of the quaternary ammonium salt contained in the extraction solution, tetramethylammonium chloride, tetramethylammonium bromide, benzyltriethylammonium chloride, methyltrioctylammonium chloride (product name Aliquat-336 or Adogen-464), tetra-n-butylammonium chloride, tetra-n-butylammonium bromide or mixtures thereof may be considered.

In addition, in some exemplary embodiments, the ionic liquid may include at least one cation of imidazolium, pyridinium, pyrazolium, or pyrrolidinium into which an alkyl group is introduced, and SbF6 - (hexafluoro antimonate), PF6 - (hexafluorophosphate), BF4 - (tetrafluoroborate), Cl- (chloride), or TFSI- (bistrifluoromethylsulfonylimide) containing at least one anion can do.

In some exemplary embodiments, the extracted vanadium may be cleaned and calcined. A cleaning solution containing an organic acid and hydrochloric acid may be used for cleaning vanadium. Also, the cleaned vanadium may be additionally calcined (first calcined). By further firing, vanadium can be precipitated in the form of V ₂ O- ₃ . The first firing may be performed at about 250 °C to 300 °C.

In addition, the precipitated V- ₂ O ₃ may be further calcined (second calcining) to recover vanadium in the form of V ₂ O ₅ . From the viewpoint of improving the uniformity and purity of V ₂ O ₅ , the second firing may be performed at 400°C to 600°C, preferably at 450°C to 550°C.

In addition, molybdenum may be removed from the extraction solution in which vanadium is recovered. In some exemplary embodiments, a mixed solution of ammonia water and ammonium chloride may be used to remove molybdenum.

In addition, CaCl ₂ may be further added to the extraction solution to which the mixed solution is added. By addition of CaCl ₂ molybdenum can be recovered in the form of CaMoO ₄ .

Through the recovery process, the valuable metal may be obtained as a solid. For example, the single metal oxide may be crystallized to obtain a solid, and the solid may be filtered to obtain a single-phase valuable metal compound.

The recovery process may be performed, for example, by neutralizing the leaching solution used in the leaching process.

According to exemplary embodiments, the leaching rate of molybdenum during the leaching may be about 97% or more based on the molybdenum content of the spent desulfurization catalyst. In addition, the leaching rate of vanadium during the leaching may be about 90% or more based on the vanadium content of the spent desulfurization catalyst.

According to exemplary embodiments, the carbon content in the leachate may be 1% by weight or less relative to the carbon content of the spent desulfurization catalyst. In this case, purity can be improved when each valuable metal is separated into a single phase in the leaching and recovery process.

Hereinafter, preferred embodiments are presented to aid understanding of the present invention, but these embodiments are only illustrative of the present invention and do not limit the scope of the appended claims, and embodiments within the scope and spirit of the present invention It is obvious to those skilled in the art that various changes and modifications to the are possible, and it is natural that these variations and modifications fall within the scope of the appended claims.

Experimental Example 1: Measurement of Valuable Metal Content in Waste Desulfurization Catalyst

Samples of spent desulfurization catalyst used in the heavy oil desulfurization process were analyzed using an Inductively Coupled Plasma (ICP) analyzer, and Ni, Mo, V, and Al contents (wt%) are shown in Table 1 below.

division Ni Mo V Al Content (wt%) 4.16 4.83 10.2 26.7

Experimental Example 2: Cleaning of spent desulfurization catalyst

The spent desulfurization catalyst sample of Experimental Example 1 was immersed in kerosene for 1, 2, 4, 24 and 48 hours, respectively, and washed.

During the washing, kerosene was used in an amount of about twice the weight of the spent desulfurization catalyst.

After washing, the spent desulfurization catalyst was dried at about 85° C. for about 1 hour.

CHNS analysis of spent desulfurization catalysts before and after cleaning shows the contents (wt%) in Table 2 below.

Cleaning time (hr) C H N S 0 (raw sample) 25.6 3.2 0.2 12.3 One 13.2 1.4 0.2 13.3 2 12.9 1.4 0.2 12.8 4 14.1 1.5 0.2 12.5 24 15.0 1.4 0.2 12.6 48 14.2 1.5 0.2 12.6

Referring to Table 2, it was confirmed that the amount of hydrocarbon impurities (components C and H) was significantly reduced when washing with kerosene for 1 hour.

Experimental Example 3: Roasting of Washed Desulfurization Waste Catalyst

The spent desulfurization catalyst cleaned for 1 hour in Table 2 was put into the reaction chamber and roasted at the temperature shown in Table 3 while introducing a mixed gas of oxygen and nitrogen (volume ratio of about 1:9) at about 25 L/min.

CHNS analysis of the roasted spent desulfurization catalyst is shown in Table 3 below.

Roasting temperature (℃) Roasting time (hr) C H N S 300 2 One 0.3 0.2 3.9 310 2 0.7 0.2 0.2 4.5 330 4 0.5 0.3 0.2 5.2 400 4 0.2 0.2 0.2 4.8

Referring to Table 3, it was confirmed that organic impurities were significantly removed during roasting at a temperature of 300° C. or higher.

Experimental Example 4: IR analysis of spent desulfurization catalyst

The spent desulfurization catalyst sample of Experimental Example 1, the spent desulfurization catalyst washed for 1 hour in Table 2, and the spent desulfurization catalyst roasted at 400° C. in Table 3 were each analyzed with an IR spectrometer to obtain IR spectra of FIGS. 3 to 5.

Comparing Figs. 3 and 4, it was confirmed that hydrocarbon impurities were significantly removed by washing.

Comparing FIGS. 4 and 5, it was confirmed that even a small amount of hydrocarbon impurities were substantially removed during roasting.

Example 1

Molybdenum and vanadium were leached from the spent desulfurization catalyst roasted at 400° C. in Table 3. Molybdenum and vananium were simultaneously extracted using an extraction solution to which Aliquat-336 (tri-n-octylmethylammonium chloride, manufactured by Sigma-Aldrich) was added. The pH of the extraction solution was 5.

Vanadium extracted by Aliquat-336 was heated at 270 °C for 2 hours to precipitate as V ₂ O _3- , and high purity V ₂ O ₅ was obtained by calcining V ₂ O ₃ at 500 °C.

Thereafter, a mixed solution of ammonia water and ammonium chloride was added to the extraction solution to remove molybdenum from the extraction solution. Molybdenum could be recovered in the form of CaMoO ₄ by supplying CaCl ₂ to the stripped molybdenum.

Examples 2 to 4

In Example 1, molybdenum and vanadium were leached in the same manner as in Example 1, except that the volume ratio of the mixed gas of oxygen and nitrogen during roasting was changed according to Table 4 below.

Experimental Example 5: Leaching amount of molybdenum and vanadium

The amounts of molybdenum and vanadium leached in Examples 1 to 4 were calculated as percentages based on the content (weight) of molybdenum and vanadium in the spent desulfurization catalyst sample of Experimental Example 1 and are shown in Table 4 below.

In Examples 1 to 4, photos of the roasted spent desulfurization catalyst are shown in Table 4 below.

Desulfurization spent catalyst sample Example 1 Example 2 Example 3 Example 4 picture Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Oxygen:nitrogen volume ratio - 1:9 2:8 3:7 4:6 Mo leach amount (%) - 67 72 89 ≥99 V Leaching amount (%) - 65 70 84 ≥95

Referring to Table 4, it was confirmed that the leaching rates of Mo and V were significantly improved in Examples 3 and 4 in which the volume ratio of oxygen:nitrogen was 3:7 or more.

Referring to FIGS. 6 to 10 , it was visually confirmed that the degree of change in the spent desulfurization catalyst increased when the oxygen content in the oxidizing gas increased. For example, it can be seen that the leaching rate of Mo and V is increased as valuable metals in the spent desulfurization catalyst are easily converted into a single metal oxide form.

Experimental Example 6: Evaluation of leaching rate according to the flow rate of oxidizing gas

In Example 3, while changing the flow rate of the oxidizing gas as shown in Table 5 below, the leaching rate of Mo and V and the content of residual carbon bound to the metal were analyzed. In order to measure the carbon content, ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer), XAS (X-ray absorption spectroscopy) and XRD (X-ray Diffraction) devices were used, and numbers below the third decimal place were omitted. .

air flow
(L/min) heating rate
(℃/min) furnace temperature
(℃) hold time
(hr) catalyst bed temperature
(℃) Mo Leachate
(%) V Leachate
(%) C content
(wt%) 25 2 450 4 410 ≥99 ≥95 0.09 6 410 ≥99 ≥95 0.06 550 4 520 ≥99 ≥95 0.05 6 520 ≥99 ≥95 0.02 5 450 4 400 ≥99 ≥95 0.64 6 410 ≥99 ≥95 0.11 550 4 510 ≥99 ≥95 0.01 6 520 ≥99 ≥95 0.01 50 2 450 4 380 ≥99 ≥95 0.31 6 380 ≥99 ≥95 0.09 550 4 510 ≥99 ≥95 0.21 6 500 ≥99 ≥95 0 5 450 4 370 ≥99 ≥95 0.25 6 370 ≥99 ≥95 0.8 550 4 490 ≥99 ≥95 0.15 6 500 ≥99 ≥95 0 5 2 450 4 415 ≥75 ≥70 1.54 6 414 ≥75 ≥70 1.48 550 4 525 ≥75 ≥70 1.39 6 525 ≥75 ≥70 1.31 5 450 4 405 ≥75 ≥70 1.79 6 414 ≥75 ≥70 1.65 550 4 513 ≥75 ≥70 1.10 6 524 ≥75 ≥70 1.02 10 2 450 4 389 ≥75 ≥70 1.13 6 383 ≥75 ≥70 0.97 550 4 511 ≥75 ≥70 1.04 6 506 ≥75 ≥70 0.91 5 450 4 372 ≥75 ≥70 1.29 6 376 ≥75 ≥70 1.17 550 4 499 ≥75 ≥70 1.31 6 505 ≥75 ≥70 1.18

Referring to Table 5, it was confirmed that when the air flow rate was 25 to 50 L/min, the leaching rate of Mo and V was significantly improved as the valuable metals in the spent desulfurization catalyst were effectively converted into a form that was easy to leach. In addition, as the hydrocarbon impurities in the spent desulfurization catalyst were effectively removed, it was confirmed that the amount of carbon in the leachate was significantly reduced.

Claims (13)

Washing a waste desulfurization catalyst containing at least one of heavy oil desulfurization, light oil desulfurization, naphtha desulfurization, catalytic cracking, heavy oil catalytic cracking, or vacuum residue desulfurization waste with a hydrocarbon-based solvent;
drying the washed spent desulfurization catalyst;
Roasting the dried waste desulfurization catalyst in an oxidizing atmosphere; and
Leaching valuable metals from the roasted spent desulfurization catalyst;
The oxidizing atmosphere includes an oxidizing gas containing oxygen and nitrogen, and the volume ratio of oxygen and nitrogen in the oxidizing gas is 3:7 to 5:5. The method for recovering valuable metals from a spent desulfurization catalyst according to claim 1, wherein the hydrocarbon-based solvent includes kerosene. delete The method for recovering valuable metals from spent desulfurization catalysts according to claim 1, wherein the drying is performed at 60 to 100°C. The method for recovering valuable metals from spent desulfurization catalysts according to claim 1, wherein the roasting is performed at 300 to 550°C. delete delete The method for recovering valuable metals from a spent desulfurization catalyst according to claim 1, wherein the roasting is performed while continuously supplying the oxidizing gas. The method for recovering valuable metals from a spent desulfurization catalyst according to claim 8, wherein the flow rate of the oxidizing gas is 25 to 50 L/min. The method for recovering valuable metals from the spent desulfurization catalyst according to claim 1, wherein less than 1% by weight of carbon relative to the carbon content of the spent desulfurization catalyst is leached out. The method for recovering valuable metals from a spent desulfurization catalyst according to claim 1, further comprising recovering the leached valuable metals. The method for recovering valuable metals from a spent desulfurization catalyst according to claim 11, wherein in the step of recovering the leached valuable metals, an extraction solution containing at least one of an ammonium-based compound and an ionic liquid is used. The method for recovering valuable metals from a spent desulfurization catalyst according to claim 12, wherein vanadium and molybdenum contained in the extraction solution are recovered in the form of V ₂ O ₅ and CaMoO ₄ , respectively.

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