KR101041378B1 - Recovery method of valuable metals and sulfur from spent petroleum catalyst - Google Patents

Abstract

The present invention relates to a method for recovering valuable metals and sulfur from a desulfurized waste catalyst, and an object thereof is to pretreat a desulfurized waste catalyst containing both a valuable metal, coke, tar and sulfur, and to remove carbon and harmful components. It is to provide a method of simultaneously recovering valuable metals through the leaching residues while increasing the leaching rate of molybdenum in the leaching process by simultaneously removing the elemental sulfur component that inhibits the leaching reaction of denium. .

The present invention comprises a first pretreatment step of removing carbon and oil components on the surface of the spent catalyst by washing the desulfurized spent catalyst with acetone; A second pretreatment step of washing and drying with CS ₂ to remove sulfur contained in the primary pretreated desulfurization waste catalyst to increase the leaching rate of molybdenum; A distillation step of recovering the elemental sulfur component dissolved in CS ₂ used in the second pretreatment step; A first leaching step of recovering valuable metals by alkali treating the desulfurized waste catalyst which has undergone the second pretreatment step with (NH ₄ ) ₂ CO ₃ ; Characterizing a method for recovering valuable metals and sulfur from the desulfurization waste catalyst comprising a second leaching step of recovering the valuable metals by acid treatment of the leaching residues discharged from the first leaching step with sulfuric acid.

Desulfurization waste catalyst, valuable metals, acetone, CS2, leaching reaction, resource recycling

Description

Recovery method of valuable metals and sulfur from spent petroleum catalyst

The present invention relates to a method for recovering valuable metals and sulfur from a desulfurization waste catalyst. Specifically, after removing oil and sulfur components from a desulfurization waste catalyst, valuable metals such as molybdenum, vanadium and nickel are efficiently leached and used. The present invention relates to a method for recovering and recycling sulfur.

When the catalyst is used for a long time in a refinery, metal sulfides, oxides and other metal compounds are adsorbed on the surface of the catalyst, thereby inhibiting the activity and properties of the catalyst.

Since the waste catalyst removed from the desulfurization tower (reactor) may ignite, it is placed in a container bag and sealed at the same time as it is discharged from the reactor to prevent ignition by blocking contact with air.

In the case of desulfurization, the VRHDS (Vacuum Residue Hydro-Desulfurization) catalyst used for the desulfurization of heavy oil is introduced into the catalyst from crude oil by at least 10% vanadium (V), at least 5% carbon combustible, and at least 10% sulfur.

Therefore, in the case of treating the desulfurization waste catalyst, the removal of sulfur, carbon, which is a combustible substance, and the treatment of V, which has the most content among the valuable metals, are considered first, and then valuable metals such as Mo and Ni are recovered.

Desulfurization waste catalysts generate about 20,000 tons annually in Korea, and about 70% of them are recycled in Korea, 23% are exported, and about 8% are landfilled.

On the other hand, since 2005, some companies have been interested in the business of recovering V and Mo from spent catalysts due to the surge in V and Mo prices. Especially, desulfurized spent catalysts containing 10% of vanadium have high economic value and are recycled. It is judged to be promising.

Since these waste desulfurized waste catalysts are hazardous wastes, additional processes for safe treatment or recovery of metals are required, and thus, development of environment-friendly treatment and recovery technologies is urgently required.

GCMC in the United States, Full-Yield Industry in Taiwan, Taiyang Industrial in Japan, and NCC are operating commercialization plants to recover valuable metals from desulfurized spent catalysts after soda roasting using water leaching.

The application process in such a commercial plant is similar in general, but there are some differences depending on the type of material to be recovered in the form of the target component and the operation method adopted in each unit process such as crushing, roasting, leaching, and precipitation reaction.

Current commercially available dry methods include direct melting, calcination and melting, and chlorinated chloride. However, when the desulfurization waste catalyst is treated by the dry method, SO ₂ is released.

In the wet method, the waste catalyst is roasted first, followed by acid or alkali leaching. However, this method also has a problem that the leaching rate of molybdenum from the waste catalyst is very low and additional SO ₂ gas treatment process is required.

In addition, since desulfurization waste catalyst contains not only valuable metals such as nickel, vanadium and molybdenum, but also coke, tar, and sulfur components at the same time, it is necessary to remove harmful components prior to the leaching reaction to increase the leaching rate of the valuable metals. There is a need to remove harmful components before leaching.

An object of the present invention for solving the above problems is to pretreat the desulfurization waste catalyst containing valuable metals, coke, tar, sulfur components at the same time to remove carbon and harmful components and to suppress the leaching reaction of molybdenum Simultaneous removal of sulfur components increases the leaching rate of molybdenum in the leaching process, and recovers valuable metals again through the leaching residue, and simultaneously distills CS ₂ used in the sulfur removal process in the desulfurization waste catalyst. It provides a method for recovering valuable metals, including the process of recovering sulfur.

The present invention to achieve the object as described above and to perform the problem for removing the conventional drawbacks comprises a first pretreatment step of removing carbon and oil components on the surface of the spent catalyst by washing the desulfurized spent catalyst with acetone;

A second pretreatment step of washing and drying with CS ₂ to remove sulfur contained in the primary pretreated desulfurization waste catalyst to increase the leaching rate of molybdenum;

A distillation step of recovering the elemental sulfur component dissolved in CS ₂ used in the second pretreatment step;

A first leaching step of recovering valuable metals by alkali treating the desulfurized waste catalyst which has undergone the second pretreatment step with (NH ₄ ) ₂ CO ₃ ;

It is achieved by providing a recovery of valuable metals and sulfur from the desulfurization waste catalyst, characterized in that it comprises a second leaching step of recovering the valuable metals by acid treatment of the leaching residue discharged from the first leaching step with sulfuric acid.

After the second pre-treatment, a pulverization step for increasing the leaching rate of the valuable metal from the desulfurization waste catalyst; characterized in that it further comprises.

The crushing step is characterized in that the washed, dried desulfurized waste catalyst is pulverized to a particle size of 45-106 ㎛.

The first leaching step is a solid solution ratio of the desulfurization waste catalyst and the leaching solution 10%, (NH ₄ ) ₂ CO ₃ addition amount 10-40 g / L, oxygen-3.5-5.0 cc / min while supplying a reaction temperature of 30 ℃ 60 minutes It is characterized in that the step of leaching the valuable metal by the reaction.

The second leaching step (NH ₄ ) ₂ leaching the valuable metals by reacting for 60 minutes at a reaction temperature of 30 ℃ while supplying 3.5-5.0 cc / min oxygen ₂ CO _3, 10-40 g / L, sulfuric acid concentration 1M conditions Characterized in that the step.

The first pretreatment step is characterized in that the step of removing the oil and carbon components by washing the desulfurization waste catalyst for 3-7 days.

The second pretreatment step is characterized in that the step of removing the sulfur component by washing the desulfurized waste catalyst after acetone treatment for 1-2 hours and then dried at 50 ℃ for 24 to 48 hours.

In the second pretreatment step, the washing is characterized by washing at reflux for 1 to 2 hours using CS ₂ .

The desulfurization waste catalyst is characterized by using a waste catalyst in which 19.5% of alumina matrix is present as nickel, 2.0% molybdenum, 1.4%, vanadium 9.0% and 11.6% sulfur as main components.

Valuable metals recovered through the first and second leaching steps are characterized in that nickel, vanadium and molybdenum.

The present invention has the advantage that the process step is simple and economically recoverable when extracting valuable metals from the desulfurization waste catalyst,

It is possible to increase the leaching rate of molybdenum in the first stage leaching process by (NH ₄ ) ₂ CO ₃ from the desulfurization waste catalyst, and by treating the leaching residue with H ₂ SO ₄ , 97% nickel, 99% vanadium, molybdenum By recovering 84% of denium, the leaching rate of valuable metals (V, Ni, Mo) was maximized.

Desulfurization waste catalyst in the distillation process to the CS ₂ used for removing sulfur and sulfur recovery groups CS ₂ is the invention that the use of industrially useful with advantages that can be recycled invention greatly expected.

Hereinafter, the configuration and the operation of the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a process for removing elemental sulfur and recovering valuable metals from a desulfurization waste catalyst according to one embodiment of the present invention.

As shown is a valuable metal recovery method according to the present invention,

Washing the desulfurized waste catalyst with acetone to remove carbon and oil components on the surface of the spent catalyst for three days;

A second pretreatment step of washing and drying with CS ₂ to remove sulfur contained in the primary pretreated desulfurization waste catalyst to increase the leaching rate of molybdenum;

A distillation step of recovering the elemental sulfur component dissolved in CS ₂ used in the second pretreatment step;

A first leaching step of recovering valuable metals by alkali treating the desulfurized waste catalyst which has undergone the second pretreatment step with (NH ₄ ) ₂ CO ₃ ;

It comprises a second leaching step of recovering the valuable metals by acid treatment of the leaching residue discharged from the first leaching step with sulfuric acid.

The present invention further includes a pulverization step for increasing the leaching rate of the valuable metal from the desulfurization waste catalyst after the second pretreatment.

In the first leaching step, the solid solution ratio of the desulfurization catalyst and the leaching solution is 10%, (NH ₄ ) ₂ CO ₃ addition amount of 10-40 g / L, oxygen 3.5-5.0 cc / min while supplying a reaction temperature of 30 ℃ 60 It is a step of leaching valuable metals by reacting for a minute. The leaching rate of valuable metals was the best in this range.

In the second leaching step is a step of leaching valuable metals by reacting for 60 minutes at the reaction temperature of 30 ℃ while supplying oxygen 3.5-5.0 cc / min in the condition of sulfuric acid concentration of 1M. The leaching rate of valuable metals was the best in this range.

The step-by-step process will be described in more detail below.

According to one embodiment of the present invention, the catalyst used as the leaching sample is a desulfurization waste catalyst, and alumina base includes nickel 2.0%, molybdenum 1.4%, vanadium 9.0% and sulfur 11.6% as main components. (See Table 1.)

Table 1. Chemical Composition of Desulfurization Waste Catalyst Sample

Element content Weight% Al 19.5 V 9 Ni 2 Mo 1.4 S 11.6 Fe 0.4

Since the desulfurization waste catalyst contains tar and oil components, in the present invention, acetone is used as a solvent to remove these components in order to increase the efficiency of the post-treatment process.

That is, the present invention was washed for 3-7 days using a soxhlet device (oil extractor) and acetone as a solvent in order to remove the oil and carbon components from the desulfurization waste catalyst before the leaching step. In this period, the removal efficiency was the best.

Conventionally, in some patents, toluene or xylene is used as the deoiling solvent of the desulfurization waste catalyst, but solvents such as xylene or toluene may change the activity of the waste catalyst because the boiling point is 100 ° C. or 110 ° C. or higher, and the reaction temperature is 100 ° C. or more. If it is increased, the cost of energy consumption increases, so it is not suitable as a solvent.

However, acetone, a solvent used in the present invention, is suitable for removing oil because its boiling point is 56 ° C.

In addition, the present invention is to inhibit the air pollution by SO ₂ gas after washing the oil component with acetone and at the same time, when the elemental sulfur is adsorbed on the surface of the desulfurization waste catalyst, that is, molybdenum metal to form a reaction layer to prevent leaching It is necessary to remove sulfur, and to this end, a pretreatment process of washing the desulfurized waste catalyst washed with acetone by refluxing with CS ₂ is included.

Thereafter, a reaction layer was formed on the molybdenum metal, and a washing process was performed with CS ₂ to remove sulfur components that hinder the leaching of molybdenum.

To this end, using a soxhlet device and CS ₂ as a solvent to wash for 1-2 hours, and then dried at 50 ℃ for 24-48 hours to remove the oil components and single sulfur.

CS ₂ used as a solvent to remove single sulfur is a colorless solvent having the same volatility, has a low boiling point (46 ° C.), and single sulfur dissolved in CS ₂ is recovered by the next step of distillation.

Thus, in the final reaction stage, sulfur is obtained in a single state and CS ₂ is reused in the washing process.

Through this process, the sulfur is recovered as the elemental sulfur, thereby eliminating the roasting process and preventing air pollution by SO ₂ gas.

If the cleaning time is short in the above washing step, the carbon and oil components cannot be completely removed, and an uneconomical problem occurs when washing for too long. Similarly, drying is the same reason.

Then, the desulfurized waste catalyst, which was subjected to the washing and drying process, was crushed into a mortar and sieved to a particle size of 45-106 μm and stored in a vacuum desiccator. The leaching efficiency of the granularity was the best.

That is, when the waste catalyst pretreated with acetone and CS ₂ was ground, the leaching rate of the metal could be increased, so it was pulverized with a ball mill and sieved below 106 μm and used as a leaching sample having a size of 45-106 μm.

The desulfurization waste catalyst after the pulverization process was leached with (NH ₄ ) ₂ CO ₃ and H ₂ SO ₄ to maximize leaching and recovery of nickel, vanadium and molybdenum from the desulfurization waste catalyst.

X-ray diffraction analysis of the sample according to the present invention shows that most of the metal is present in oxide and sulfide states. Vanadium is present in oxide form V ₄ O ₉ and nickel is present in sulfide form Ni _3-x S ₂ , while molybdenum is present in oxide form e MoO ₃ and sulfide Mo ₃ S ₄ .

Vanadium oxides and nickel sulfides are leached in acids, but molybdenum oxides and sulfides are more easily leached in alkali than acids. In the present invention using the leaching characteristics of the metal oxides and sulfides in the present invention, the desulfurized waste catalyst, which has undergone the washing step by pretreatment, is first leached with alkali phosphorus (NH ₄ ) ₂ CO ₃ to leach molybdenum to a considerable amount, and H ₂ SO ₄ We tried to increase the leaching rate of vanadium and nickel in the secondary leaching using.

The leaching test according to an embodiment of the present invention was carried out in a 500cc pyrex reactor, the reaction solution was stirred at 500 rpm using a mechanical stirrer.

The reaction vessel and the reaction temperature were the same in the first alkali leaching with (NH ₄ ) ₂ CO ₃ and the second acid leaching with H ₂ SO ₄ , and oxygen was constantly supplied at 3.5 to 5.0 cc / min.

Experimental conditions for the first step (NH ₄ ) ₂ CO ₃ leaching was the solid-liquid ratio of desulfurization catalyst and leaching solution 10%, reaction temperature 30 ℃, reaction time 60 minutes and (NH ₄ ) ₂ CO ₃ addition amount is 10-40 The change was in the g / L range.

According to these leaching conditions, the waste catalyst washed with CS ₂ was leached _first with (NH ₄ ) ₂ CO ₃ to leach molybdenum in the desulfurized waste catalyst. Thereafter, a leaching residue containing a considerable amount of nickel and vanadium was leached secondly with 1M H ₂ SO ₄ to leach nickel and vanadium.

When the first and second leaching reactions were carried out at 30 ° C. for 60 minutes, nickel and vanadium were more than 97% and molybdenum was leached and recovered about 84%.

In particular, the leaching solution of the optimum conditions derived from the present invention is dissolved in nickel 97%, vanadium 99%, molybdenum 84%, leaching solution in which valuable metals are dissolved by using a solvent extraction (Solvent Extraction) technology, Molybdenum is separated separately.

As described above, the present invention is an economical process for maximizing the leaching rate of valuable metals (V, Ni, Mo) from the desulfurization waste catalyst and recovering elemental sulfur.

Hereinafter, a description will be given of the specific variables for the present invention.

Characterization of Removal of Sulfur Components by CS ₂

In order to improve the leaching rate of valuable metals during acid and alkali treatment from the desulfurization waste catalyst, the elemental sulfur adsorbed on the desulfurization waste catalyst surface was removed. That is, the desulfurized waste catalyst first washed with acetone was charged to a Soxhlet apparatus, and the elemental sulfur component was removed by refluxing for 1-2 hours while heating CS ₂ at 46 ^° C. or higher.

Figure 2a shows in detail the X-ray diffraction analysis results for the sample washed with acetone, Figure 2b shows the X-ray diffraction analysis results for the sample removed the sulfur component with CS ₂ in detail.

As shown in the sample washed with acetone, the peak of the single sulfur can be seen, the sample washed with CS ₂ showed no peak of single sulfur. That is, it can be seen that most of the elemental sulfur was removed from the desulfurization waste catalyst by washing with CS ₂ .

(Analysis of Changes in Addition Amount of (NH ₄ ) ₂ CO ₃ 1)

Leaching experiments were performed on desulfurized spent catalyst samples washed with acetone and CS ₂ . Desulfurization of waste catalyst and the solid-liquid ratio of 10% of the leaching solution, the reaction temperature 30 ℃, reaction time 60 minutes, the oxygen amount _{3.5~5.0 cc / min, (NH 4} ) 2 The amount 10 g / L (distilled water 1L basis) of CO ₃ The first leaching experiment was carried out under the conditions. (See Table 2.).

Table 2. Leaching rate of valuable metals in the first leaching after washing with acetone and CS ₂ (solid solution ratio 10%, reaction temperature 30 ℃, reaction time 60 minutes, oxygen input amount 3.5 ~ 5.0 cc / min)

(NH ₄ ) ₂ CO ₃ , (g / L) Ni (%) V (%) Mo (%) 10 One 21 50 20 2 34 54 30 3 36 56 40 5 38 60

As a result of leaching, 50% of Mo and 21% of V were leached, but 1% of Ni was hardly leached. In other words, nickel sulfide was easily leached in the acidic region of pH 0.5-1.0, but nickel was almost not leached in the alkaline region (pH 8.68).

(Analysis of Changes in Addition Amount of (NH ₄ ) ₂ CO ₃ 2)

Leaching experiments were performed on desulfurized spent catalyst samples washed with acetone and CS ₂ . Solids ratio of leaching solution other than desulfurization waste catalyst 10%, reaction temperature 30 ℃, reaction time 60 minutes, oxygen input amount 3.5-5.0 cc / min, (NH ₄ ) ₂ CO ₃ addition amount 40 g / L (based on 1L distilled water) The first leaching experiment was carried out under the conditions. (See Table 2.).

In the leaching test, 60% of Mo, 38% of V, and 5% of Ni were leached. Compared with molybdenum and vanadium, the leaching rate of nickel was still very low.

(Analysis of the reaction time when (NH ₄ ) ₂ CO _{3 is} added)

Leaching experiments were performed on desulfurized spent catalyst samples washed with acetone and CS ₂ . Reaction time up to 5-60 minutes under conditions of 10% solids ratio of leaching solution other than desulfurization catalyst, reaction temperature 30 ℃, oxygen input amount 3.5 ~ 5.0 cc / min, addition amount of (NH ₄ ) ₂ CO ₃ 40 g / L The leaching behavior of valuable metals was investigated by changing the values. (See Figure 3).

As a result of the leaching test, the leaching rate of Mo was 48% in the 15-minute reaction and 58% in the 30-minute reaction. In the case of V, 26% in 15 minutes, 30% in 30 minutes, 36% in 45 minutes, 38% in 60 minutes were leached. The leaching rate of Ni was 1.5-5.2%, which was very low compared to the leaching rates of Mo and V.

(Secondary Leaching Characteristics Analysis by H ₂ SO ₄ )

After the leaching of the desulfurized waste catalyst washed with acetone and CS ₂ (NH ₄ ) ₂ CO _3, 10-40 g / L, the leaching experiment was carried out with sulfuric acid for the second leaching of the leaching residue containing valuable metals. Was carried out. At this time, the leaching experiment conditions were the solid-liquid ratio of desulfurization catalyst and leaching solution 10%, reaction temperature 30 ℃, reaction time 60 minutes, oxygen input amount 3.5-5.0 cc / min, H ₂ SO ₄ 1M 250cc.

As a result of the second leaching with sulfuric acid, 90-93% of nickel was leached regardless of the amount of alkali added in the first leaching experiment. However, vanadium leached 50-61% and molybdenum 12-24%, depending on the amount of alkali added. (See Table 3)

Table 3. Leaching rate of valuable metals in the second leaching after washing with acetone, CS ₂ (H ₂ SO ₄ 1M, reaction temperature 30 ℃, reaction time 60 minutes, oxygen input amount 3.5 ~ 5.0 cc / min)

Primary leaching condition Leaching rate of each metal (NH ₄ ) ₂ CO ₃ , (g / L) Ni (%) V (%) Mo (%) 10 90 50 12 20 91 55 14 30 93 60 20 40 92 61 24

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

1 is a process for removing elemental sulfur and valuable metals from a desulfurization waste catalyst according to one embodiment of the present invention,

Figure 2a is an X-ray analysis of the sample washed with acetone in accordance with the present invention,

2b is an X-ray analysis result of the sample washed with CS ₂ according to the present invention,

3 is a graph of the leaching rate change rate of valuable metals according to the reaction time during the first leaching according to the present invention.

Claims (10)

A first pretreatment step of washing the desulfurization waste catalyst with acetone to remove carbon and oil components on the surface of the waste catalyst; A second pretreatment step of washing and drying with CS ₂ to remove sulfur contained in the primary pretreated desulfurization waste catalyst to increase the leaching rate of molybdenum; A distillation step of recovering the elemental sulfur component dissolved in CS ₂ used in the second pretreatment step; A first leaching step of recovering valuable metals by alkali treating the desulfurized waste catalyst which has undergone the second pretreatment step with (NH ₄ ) ₂ CO ₃ ; A method for recovering valuable metals and sulfur from a desulfurization waste catalyst comprising a second leaching step of recovering valuable metals by acid-treating the leaching residue discharged from the first leaching step with sulfuric acid. The method according to claim 1, After the second pre-treatment, a pulverizing step for increasing the leaching rate of the valuable metals from the desulfurization waste catalyst; recovery method of valuable metals and sulfur from the desulfurization waste catalyst further comprising. The method according to claim 2, The crushing step is a method for recovering valuable metals and sulfur from the desulfurized waste catalyst, characterized in that the washed, dried desulfurized waste catalyst is crushed to a particle size of 45-106㎛. The method according to claim 1 or 2, The first leaching step is a solid solution ratio of the desulfurization waste catalyst and the leaching solution 10%, (NH ₄ ) ₂ CO ₃ addition amount 10-40 g / L, oxygen-3.5-5.0 cc / min while supplying a reaction temperature of 30 ℃ 60 minutes A method for recovering valuable metals and sulfur from the desulfurization waste catalyst, characterized in that the step of leaching the valuable metal by the reaction. The method according to claim 1 or 2, The second leaching step (NH ₄ ) ₂ leaching the valuable metals by reacting for 60 minutes at a reaction temperature of 30 ℃ while supplying 3.5-5.0 cc / min oxygen ₂ CO _3, 10-40 g / L, sulfuric acid concentration 1M conditions Method for recovering valuable metals and sulfur from the desulfurization waste catalyst, characterized in that the step of. The method according to claim 1, The first pretreatment step is a method for recovering valuable metals and sulfur from the desulfurized waste catalyst, characterized in that to remove oil and carbon components by washing the desulfurized waste catalyst for 3 to 7 days. The method according to claim 1, The second pretreatment step is a method for recovering valuable metals and sulfur from the desulfurized waste catalyst, characterized in that the desulfurized waste catalyst after acetone treatment is washed for 1-2 hours and dried at 50 ° C. for 24 to 48 hours to remove sulfur components. . The method according to claim 1, In the second pretreatment step, the washing is carried out at reflux for 1 to 2 hours using CS ₂ to recover valuable metals and sulfur from the desulfurized waste catalyst. The method according to claim 1, The desulfurization waste catalyst is composed of valuable metals and sulfur from the desulfurization waste catalyst, characterized in that a waste catalyst having 19.5% alumina base, nickel 2.0%, molybdenum 1.4%, vanadium 9.0% and sulfur 11.6% is used as a main component. Recovery method. The method according to claim 1, The valuable metals recovered through the first and second leaching steps are nickel, vanadium and molybdenum, and recovering valuable metals and sulfur from the desulfurization waste catalyst.

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