KR101107010B1 - Recovery method of valuable metals by pretreatment of spent petroleum catalyst and sulphuric acid - Google Patents

Abstract

The present invention relates to a pretreatment of a desulfurization waste catalyst and a method for recovering valuable metals using sulfuric acid. The object of the present invention is to remove harmful components in advance before leaching reaction of desulfurization waste catalysts containing valuable metals, coke, tar, and sulfur components. It is to provide a method for leaching and recovering valuable metals in a simple process while preventing environmental pollution.

The composition of the present invention comprises the steps of: (A) a pre-treatment step of washing the desulfurization waste catalyst with acetone and drying to remove carbon and oil components on the surface of the waste catalyst; (B) treating the desulfurized waste catalyst from which the oil component has been removed by leaching sulfuric acid to leach valuable metals; and a method for recovering valuable metals using sulfuric acid.

Desulfurization waste catalyst, valuable metals, acetone solvent, sulfuric acid leaching, resource recycling

Description

Recovery method of valuable metals by pretreatment of spent petroleum catalyst and sulphuric acid}

The present invention relates to a pretreatment of a desulfurization waste catalyst and a method for recovering valuable metals using sulfuric acid, and more particularly, to a process of leaching valuable metal components with sulfuric acid after washing the oil component from the desulfurization waste catalyst with acetone.

Desulfurization waste catalyst, which is a solid waste discharged from the petrochemical industry, contains various metals and organic substances such as Al, Ni, Co, V, and Mo.

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

Molybdenum and vanadium, in particular, are the main raw materials for catalysts widely used in the petrochemical, chemical and aerospace industries and are important strategic metals used in the steel industry.

In the past, most of these metals were extracted and used from ore or mineral resources, but recently, attention has been focused on the development of technology for recovering these metals from waste resources and secondary resources due to price increases due to resource depletion and shortage of supply.

Meanwhile, about 20,000 tons of desulfurized waste catalyst is generated annually in Korea, and about 70% of the generated amount is recycled in Korea, 22% is exported, and about 8% is landfilled.

In particular, the 10% desulfurized spent catalyst containing about 10% vanadium has high economic value and is considered to be promising to be recycled.

In general, the desulfurized waste catalyst containing molybdenum and vanadium varies depending on the number of times used and the impurity content, but is generally disposed of after two to three years at a refinery.

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

GCMC in the US, Full-Yield Industry in Taiwan, Taeyang Industrial Co. in Japan, and NCC are operating commercialization plants to recover valuable metals from petrochemical waste catalysts using the water leaching method after soda roasting.

The overall process in such a commercial plant is similar, but there are differences in each unit process such as crushing, roasting, and leaching depending on the type of metal to be recovered.

However, when the desulfurization waste catalyst is treated by the dry method, SO _{2, which} is a harmful gas, is generated, and thus, a problem that requires an additional SO ₂ gas treatment process is emerging.

In addition, since the desulfurization waste catalyst contains not only valuable metals to be extracted but also coke, tar and sulfur components at the same time, it is necessary to remove harmful components in advance of the leaching reaction.

An object of the present invention for solving the above problems is a simple process while removing the harmful components in advance of the leaching reaction of the desulfurization waste catalyst containing valuable metals, coke, tar, sulfur components to prevent environmental pollution, It is to provide a method for leaching and recovering valuable metals.

The present invention to achieve the object as described above and to perform the problem for removing the conventional defects (A) a pre-treatment step of removing the carbon and oil components on the surface of the spent catalyst by washing and drying the desulfurized spent catalyst with acetone;

(B) treating the desulfurized waste catalyst from which the oil component has been removed with sulfuric acid (leaching) to leach valuable metals; and providing a pretreatment of the desulfurized waste catalyst and recovering valuable metals using sulfuric acid, the method comprising: Is achieved.

The present invention is also characterized in that it further comprises a; after the step (A), (C) a pulverization step for increasing the leaching rate of valuable metals from the desulfurization catalyst.

Step (C) is characterized in that the washed, dried desulfurized waste catalyst is ground to a particle size of 45-106 ㎛.

In the step (B), the desulfurization spent catalyst and sulfuric acid were used as a solid-liquid ratio of 10 to 40%, and reacted for 5 to 180 minutes at a reaction temperature of 30 to 50 ° C. while supplying 3.5 to 5.0 cc / min of oxygen under a sulfuric acid concentration of 1 M. It is characterized in that the step of leaching valuable metals.

The desulfurization waste catalyst is characterized in that the waste catalyst in which nickel, molybdenum, vanadium and sulfur are present as a main component on the alumina base.

The leaching valuable metal is characterized in that any one or more of nickel, vanadium, molybdenum.

Step (A) is a step of removing the oil component by washing the desulfurization waste catalyst for 3 to 7 days and then dried at 50 ℃ for 24 to 72 hours.

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

When sulfur is separated into leach residues in order to suppress air pollution by SO ₂ gas when recovering valuable metals from spent catalysts, it is a useful invention with an environmentally-friendly advantage of recovering more than 80% of nickel and vanadium. By separating the denium into leach residues, it is an invention that is expected to be used in the industry which can further process only molybdenum having low leaching efficiency when leaching sulfuric acid.

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 graph showing the X-ray analysis of the desulfurized waste catalyst washed with acetone, Figure 2 is a graph of leaching rate of valuable metals with the change of reaction time, Figure 3 is a SEM-EDX analysis photograph of the leaching residue.

The present invention comprises (A) a pretreatment step of washing the desulfurized waste catalyst with acetone and drying to remove oil components on the surface of the spent catalyst; (B) a step of leaching valuable metals by treating the desulfurized waste catalyst from which the oil component has been removed by a chemical leaching method.

In addition, after the step (A), (C) may further comprise a grinding step to increase the leaching rate of the desulfurization waste catalyst.

Step (A) was a pre-leaching step to remove oil components from the desulfurization waste catalyst, using a soxhlet device (oil extractor) and acetone as a solvent for about 3-7 days and then dried at 50 ℃ for 24-72 hours. The washed and dried desulfurized waste catalyst was pulverized with a mortar and then sieved to 45-106 μm particle size and stored in a vacuum desiccator.

If the cleaning time is short in the above it is not possible to remove the carbon and oil components completely, it causes an uneconomical problem when washing too long. Similarly, drying is the same reason.

In the present invention, after washing the oil component with acetone, the sulfur component is to be separated into a leach residue in order to suppress air pollution by SO ₂ gas. In addition, leaching with sulfuric acid to recover more than 80% of valuable metals such as nickel, vanadium and molybdenum.

In the present invention, the catalyst used as the leaching sample is a desulfurization waste catalyst, and nickel, molybdenum, vanadium and sulfur are present as the main components in the alumina base.

The present invention includes a pretreatment step of washing with acetone to remove carbon and oil components from the desulfurization waste catalyst.

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 higher. 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 can increase the leaching rate of the metal when the waste catalyst pretreated with acetone as in step (C) can increase the leaching rate of the metal and pulverized in a ball mill and used as a leaching sample.

X-ray diffraction analysis (see Table 1) for the sample according to the present invention shows that most of the metal is present in the 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 .

Table 1. Leaching Rate of Valuable Metals by Reaction Temperature

(Solid ratio: 10%, Sulfuric acid concentration: 1M, Oxygen amount: 3.5-5.0 cc / min)

Molybdenum (%) Vanadium (%) Nickel (%) Time
(min.) 30 ^o C 40 ^o C 50 ^o C 30 ^o C 40 ^o C 50 ^o C 30 ^o C 40 ^o C 50 ^o C 0 16 18 20 35 46 50 30 45 52 10 20 23 25 43 60 62 40 60 65 30 24 26 28 70 75 78 65 70 75 45 26 30 35 82 89 90 75 78 85 60 27 32 37 84 90 97 78 88 96 90 28 33 38 86 92 98 83 92 97

In the present invention, the leaching reaction was carried out in a relatively low temperature range of 30-50 ℃, nickel and vanadium present in the desulfurization waste catalyst can be easily leached in sulfuric acid atmosphere of about 1M.

 At acidic pH levels between 0.5 and 0.6, significant amounts of nickel sulfide and vanadium oxide in the spent catalyst sample are leached into the solution. However, molybdenum sulfide is only partially leached compared to other metals.

 Since the elemental sulfur forms a reaction layer on the molybdenum metal to prevent leaching, it is necessary to remove the elemental sulfur as a reaction layer in order to leach molybdenum.

In the final leachate of the present invention, nickel, vanadium and molybdenum are present as main metal ions.

In addition, the main component of the solid leach residue is alumina (Al ₂ O ₃ ) and there is some Mo sulfide not leached into sulfuric acid. The leaching solution in which the valuable metal is dissolved separates nickel and vanadium using a solvent extraction technique.

Hereinafter, the leaching step by the sulfuric acid leaching method according to step (B) in the present invention. In the present invention, 250 cc of 1M sulfuric acid solution was prepared in an Erlenmeyer flask, and then, a predetermined amount of desulfurized waste catalyst was added thereto, and stirred with a mechanical stirrer. The experimental conditions were agitation speed of 500 rpm, and the most preferable result was a reaction time of 5 to 180 minutes. The best results were obtained at 30-50 ℃ and solid concentration of 10-40%.

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

(Desulfurization catalyst characteristics investigation)

X-ray diffraction analysis was performed on the sample to investigate the physical characteristics of the desulfurized spent catalyst. The leaching agent can be determined according to the properties of the inorganic phase present in the sample, that is, the application of oxides or sulfides. In the case of a sulfide sample, since an oxidant is required during leaching, the phase states of nickel, vanadium and molybdenum present in the desulfurization waste catalyst are first shown in FIG. 1. As shown, sulfur is present as single sulfur, vanadium is present in oxide form V ₄ O ₉ , nickel is present in sulfide form Ni _3-x S ₂ , while molybdenum is an oxide of e MoO ₃ and sulfide It coexists in Mo ₃ S ₄ form.

(Influence of leaching time)

Leaching conditions of valuable metals were derived from the desulfurized waste catalyst washed with acetone.

Leaching characteristics of the valuable metals with varying reaction time were investigated while supplying 3.5-5.0 cc / min of oxygen at 10% solids ratio and 1M sulfuric acid concentration. (See Figure 2)

As a result of leaching test, leaching speed of valuable metals was fast up to 30 minutes of initial reaction, but leaching speed was not changed from 1 hour after reaction time. In other words, Ni was 70.9%, V was 77.7%, Mo 23.0% was leached at 30 minutes, and Ni was 78.9%, V was 83.9%, Mo 26.7% at 60 minutes. In 90 minutes of reaction, 84.9% of Ni, 86.7% of V, and 28.5% of Mo were leached. The leaching rate of valuable metals did not change during 90 ~ 180 minutes.

It is considered that the sulfur generating layer present on the surface of molybdenum inhibits leaching of Mo and thus the leaching rate of Mo is lower than that of other metals.

SEM-EDX analysis confirmed the presence of Mo sulfide in the leaching residue. (See Fig. 3)

(Influence of reaction temperature)

Leaching conditions of valuable metals were derived from the desulfurized waste catalyst washed with acetone.

Leaching characteristics of the valuable metals with varying reaction temperatures were investigated with oxygen supply of 3.5-5.0 cc / min under a 10% solids ratio and 1M sulfuric acid concentration. (See Table 1)

As a result of the leaching experiment, the reaction temperature was changed in the range of 30-50 ℃ at 10 ℃ intervals. As the reaction temperature increased under all experimental conditions, the leaching rate of valuable metals increased. In 90 minutes, molybdenum leached 28% at 30 ° C, 33% at 40 ° C, 38% at 50 ° C, and vanadium leached at 86% at 30 ° C, 92% at 40 ° C and 98% at 50 ° C. . Nickel leached 83% at 30 ° C, 92% at 40 ° C and 97% at 50 ° C.

(Influence of high liquid concentration)

Leaching conditions of valuable metals were derived from the desulfurized waste catalyst washed with acetone.

The leaching characteristics of valuable metals with varying solid concentrations were investigated while supplying oxygen at 3.5-5.0 cc / min under the reaction time of 90 minutes, sulfuric acid concentration of 1M and reaction temperature of 30 ℃. (See Table 2)

As a result of the leaching experiment, the solid solution concentration was changed in the range of 10-40%. As a result, the leaching rate of the molybdenum decreased rapidly as the solid solution concentration increased. In other words, molybdenum leaching was 28% at a high liquid concentration of 10%, but only 12% at 20% and 7% at 40%.

Table 2. Leaching Rate of Valuable Metals with Changes in Liquid Concentration

(Reaction time: 90 minutes, sulfuric acid concentration: 1M, reaction temperature: 30 ℃,

 Oxygen amount: 3.5 to 5.0 cc / min)

metal
Pulp density
(%) Ni (%) V (%) Mo (%) 10 83 86 28 20 86 88 12 30 87 89 9 40 85 88 7

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 graph showing the results of X-ray analysis of desulfurized spent catalyst washed with acetone,

2 is a graph of leaching rate of valuable metals according to the change of reaction time,

3 is a SEM-EDX analysis photograph of the leaching residue.

Claims (7)

(A) a pretreatment step of washing the desulfurized waste catalyst with acetone and drying to remove carbon and oil components on the surface of the spent catalyst; (B) a step of leaching valuable metals by treating the desulfurized waste catalyst from which the oil component is removed by a sulfuric acid leaching method; In the step (B), the desulfurization spent catalyst and sulfuric acid are solid solution ratio of 10 to 40%, and reacted for 5 to 180 minutes at a reaction temperature of 30 to 50 ° C. while supplying 3.5 to 5.0 cc / min of oxygen under a sulfuric acid concentration of 1 M. Pretreatment of the desulfurization waste catalyst and sulfuric acid recovery method using sulfuric acid, characterized in that the leaching of valuable metals. The method according to claim 1 After the step (A), (C) a pulverization step for increasing the leaching rate of the valuable metals from the desulfurization waste catalyst; pre-treatment and recovery of valuable metals using sulfuric acid, characterized in that it further comprises. The method according to claim 2 The step (C) is a pre-treatment of the desulfurized waste catalyst and recovery of valuable metals using sulfuric acid, characterized in that the washed, dried desulfurized waste catalyst is pulverized to a particle size of 45-106㎛. delete The method according to claim 1, The desulfurization waste catalyst is a pre-treatment of a desulfurization waste catalyst and a valuable metal recovery method using sulfuric acid, wherein the desulfurization waste catalyst is a waste catalyst in which nickel, molybdenum, vanadium and sulfur are present as a main component in an alumina base. The method according to claim 1, The leaching valuable metal is any one or more of nickel, vanadium, molybdenum, pre-treatment of the desulfurization catalyst and recovery of valuable metal using sulfuric acid. The method according to claim 1, Step (A) is a pre-treatment of the desulfurized waste catalyst and a valuable metal recovery method using sulfuric acid, characterized in that the desulfurized waste catalyst is washed for 3 to 7 days and then dried at 50 ° C. for 24 to 72 hours to remove oil components. .

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