KR101545968B1 - Method for recovery of valuable metals from waste materials - Google Patents

Abstract

The present invention can efficiently separate valuable metals such as molybdenum and cobalt from the leach solution by leaching wastes containing valuable metals such as waste catalysts as leachate through a solvent extraction method, The present invention relates to a method for recovering an economically valuable metal.
The method according to the present invention comprises the steps of: (a) contacting a first organic solvent with a spent catalyst leach solution to selectively extract molybdenum from the first organic solvent; (b) separating the molybdenum from the first organic solvent (C) selectively extracting cobalt from the second organic solvent by contacting a second organic solvent with the extracted filtrate from which the molybdenum has been extracted, and (d) 2 < / RTI > organic solvent.

Description

[0001] METHOD FOR RECOVERY OF VALVE METALS FROM WASTE MATERIALS [0002]

The present invention relates to a method for recovering valuable metals from waste catalysts, and more particularly, to a method for recovering valuable metals such as molybdenum and cobalt from a leach solution through a leaching solution after leaching the spent catalyst containing a valuable metal, And a method of recovering an economically valuable metal by recycling a material used in each process.

Cobalt is a valuable metal and it does not have any resources in Korea, so most of domestic consumption is dependent on imports. In addition, cobalt is used as an electrode material, and it is expected that future price will rise due to expansion of battery market. Therefore, recovery of cobalt from secondary sources occurring in Korea is very important in terms of ensuring the basic materials required for industrial development. In addition, taking into account the fact that the ore containing the valuable metals is poor, the mineralization of the ore is expected to follow the recent petroleum. Therefore, the recovery technology of the valuable metals from the waste resources generated in the domestic or nearby countries is essential for the continuous development of the domestic industry .

Meanwhile, cobalt and molybdenum are contained in waste catalysts used in the petrochemical refining process. During purification, rare metals such as vanadium and nickel are incorporated into the spent catalyst. Therefore, it is important to recover metals such as molybdenum, vanadium and nickel as well as cobalt contained in a large amount from waste catalysts generated in a petrochemical refining process in high purity.

Methods for recovering valuable metals contained in spent catalysts include gas-phase transprot, support dissolution, melting, and leaching.

In the vapor phase transfer process, a large amount of energy is consumed by evaporating and recovering the noble metal. In the carrier dissolution process, the carrier is selectively dissolved in an acid or a base. Therefore, the purification process is complicated and requires a large amount of solvent. Melting process Since a noble metal is recovered by using a difference in melting point and density between a carrier and a noble metal after dissolving the catalyst, a large amount of energy is required and impurities are also dissolved at the same time, so that subsequent purification is difficult.

Generally, a wet smelting process including a leaching process, a separation process, and a purification process is economically advantageous in recovering valuable metals from resources such as waste catalysts.

On the other hand, when an organic solvent such as TOPO is used to recover a valuable metal such as molybdenum contained in the spent catalyst leach solution, more than 99% of molybdenum can be extracted from the leached solution. However, in order to remove the extracted molybdenum, it is necessary to use a concentrated acid or a base. Such a process using a concentrated acid and a base has a problem in that the process cost is increased and the economical efficiency is lowered.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a process for recovering molybdenum and cobalt from waste catalyst leaching solution by solvent extraction, Or the base can be removed and the salt used for leaching can be efficiently regenerated, thereby providing a method for economically recovering valuable metals.

According to a first aspect of the present invention, there is provided a method for producing molybdenum, comprising the steps of: (a) bringing a first organic solvent into contact with a waste catalyst leach solution to selectively extract molybdenum from the first organic solvent; (b) (C) selectively extracting cobalt from the second organic solvent by contacting a second organic solvent with the extracted filtrate from which the molybdenum has been extracted, and (d) removing the molybdenum from the first organic solvent by And removing the cobalt from the second organic solvent from which the cobalt is extracted.

According to one embodiment of the present invention, a valuable metal such as molybdenum and cobalt contained in the spent catalyst can be efficiently separated.

Further, according to one embodiment of the present invention, in recycling the organic solvent used in each step, it is possible to use a low-concentration acid, which can increase the economical efficiency of the process.

Further, according to the embodiment of the present invention, recycling of the hydrochloric acid used for leaching the spent catalyst is easy, and the economical efficiency of the process can be improved.

1 is a process flow diagram illustrating a process for recovering valuable metals from a spent catalyst according to an embodiment of the present invention.
FIG. 2 shows leaching rates of valuable metals (Mo, Co, Al, Fe, Ni and Si) according to the concentration of hydrochloric acid and the leaching time at room temperature.
FIG. 3 shows the difference in leaching rate depending on leaching temperature when leaching using 2 mol / L hydrochloric acid and 3 mol / L hydrochloric acid.
Fig. 4 shows the leaching rate according to the leaching ratio at the time of leaching.
5 shows the extraction rates of the valuable metals (Mo, Co, Al) according to the concentration of TBP.
6 shows the extraction rates of the valuable metals (Co and Al) and hydrochloric acid (HCl) according to the concentration of Alamine 308. FIG.
7 shows the extraction isotherm curves for cobalt extraction using Alamine 308 under predetermined test conditions (2.9 mol / L hydrochloric acid leach solution, Alamine: 0.1 mol / L, diluent: kerosene, A / O ratio: extraction isotherm plot.
Figure 8 shows the extraction rate of hydrochloric acid according to the concentration of TEHA.
9 is a McCabe-Thiele plot when hydrochloric acid is extracted using TEHA under predetermined test conditions (2.9 mol / L hydrochloric acid leaching solution, TEHA: 0.1 mol / L, diluent: Kerosene, O / A ratio: 1 to 6) .
10 is a McCabe-Thiele plot of a process for removing hydrochloric acid from TEHA in which hydrochloric acid is extracted with a predetermined test condition (TEHA: 1.35 mol / L, diluent: kerosene, stripper: distilled water, O / A ratio: 1 to 7) .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described 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.

Also, when a part is referred to as "including " an element, it does not exclude other elements unless specifically stated otherwise.

The present inventors have succeeded in recovering molybdenum and cobalt, which are valuable metals, from a spent catalyst (Mo / Co-Al ₂ O ₃ ) used in a petrochemical purification process by a solvent extraction method at a high recovery rate and at the same time, As a result of intensive research on a method for efficiently recovering valuable metals from waste catalysts, it is possible to economically remove molybdenum (Mo) selectively from a waste catalyst leach with a first organic solvent which is easy to remove, (Co) can be selectively separated from the leached filtrate of the first organic solvent by using a second organic solvent which can be easily removed, and the third organic solvent which is easy to remove can be used for leaching cobalt Hydrochloric acid can be selectively separated from the filtrate, and the leachate, the first organic solvent, the second organic solvent, the third organic solvent, and hydrochloric acid as the leaching solution can be easily recycled at low cost The cost of recovering the valuable metal can be greatly reduced, leading to the present invention.

As shown in FIG. 1, the process for recovering valuable metals from the spent catalyst according to the present invention comprises a cleaning step (S10) of a spent catalyst, a leaching step (S20) of a washed spent catalyst, a solid-liquid separation step (S30) (S40) of extracting molybdenum (Mo) from the leach solution using TBP, a stripping step (S50) of molybdenum (Mo) extracted, and a step of extracting molybdenum (S80) of extracting cobalt (Co), a step (S70) of removing extracted cobalt (Co), a step (S80) of extracting hydrochloric acid using TEHA from the extracted filtrate from which cobalt (Co) , And a step (S90) of removing the extracted hydrochloric acid.

The washing step (S10) of the spent catalyst is a step for removing soluble organic impurities contained in the waste catalyst. The organic impurities adhered to the surface of the waste catalyst are removed using a solvent capable of removing organic components such as acetone And then dried in an oven heated to about 80 캜 for 6 hours or more. In the present invention, acetone is used as a cleaning solvent. However, the present invention is not limited thereto, and any material capable of exhibiting an effect similar to acetone may be used without limitation.

The leaching step (S20) of the spent catalyst is a step of dissolving molybdenum (Mo) and cobalt (Co), which are valuable metals, from the spent catalyst and may be carried out by adding hydrochloric acid (HCl) or hydrogen peroxide (H ₂ O ₂ ) A material mixed with an oxidizing agent such as sodium chloride (NaClO) may be used, and an extract containing hydrogen peroxide (H ₂ O ₂ ) of 2 to 5 times the stoichiometric ratio of chlorine to be extracted to hydrochloric acid may be used.

The solid-liquid separation step (S30) may be performed using various known solid-liquid separation processes, for example, a vacuum filter may be used to separate the leachate from the leach residue.

The extracting step S40 of the molybdenum (Mo) is a step of selectively extracting only molybdenum (Fe) from the leaching solution. The extracting agent is preferably TBP (Tri-n-butyl Phosphate) / L, most of the molybdenum (Mo) can be recovered from the leachate, so that it is preferably 0.5 mol / L or more. The TBP may include a kerosene having a low cost and material stability as a diluent, and is not limited to a material capable of dissolving TBP such as toluene.

The molybdenum (Mo) stripping process (S50) is a process for recovering molybdenum and regenerating TBP. As the removing process, hydrochloric acid may be used. The concentration of hydrochloric acid may be 0.1 to 3M diluted hydrochloric acid.

It is preferable to use Alamine 308 (Tri-iso-octyl Amine) as the extraction step (S60) of cobalt (Co) from the extraction filtrate from which molybdenum (Mo) is extracted. When Alamine 308 is used as the extracting agent, molybdenum Mo) and cobalt (Co) are co-extracted, they must be used after molybdenum (Mo) is removed. The Alamine 308 may include a kerosene having a low cost and material stability as a diluent, and is not limited to a substance capable of dissolving Alamine 308 such as toluene. Almost all cobalt (Co) is extracted at a concentration of 0.5 mol / L or more of Alamine 308, and the extraction rate of impurities such as aluminum (Al) is very low. However, since the removal of Alamine 308 is not easy as the concentration of Alamine 308 increases, the concentration of Alamine 308 is preferably 0.1 mol / L to 0.5 mol / L. At this time, if the concentration of Alamine 308 is kept as low as 0.1 mol / L, it is preferable to perform at least three stages of multi-stage extraction. When Alamine 308 is used, it may further include a modifier such as 1-decanol to inhibit the formation of the third phase.

The step (S70) of removing the extracted cobalt (Co) is a step of removing cobalt (Co) from the cobalt (Co) extract and regenerating the extractant Alamine 308. The removal is preferably dilute hydrochloric acid (HCl) The concentration of hydrochloric acid (HCl) used as a large liquid is at least 0.5 M or more, preferably 1 M or more.

It is preferable to use TEHA (tri 2-ethyl hexyl amine) as the extracting step (S80) of hydrochloric acid (HCl) as the leaching solution from the extraction filtrate from which cobalt (Co) is extracted. When TEHA is used as the extracting agent, It is necessary to extract at least three stages. The TEHA may include a kerosene having a low cost and material stability as a diluent, and is not limited to a material capable of dissolving TEHA such as toluene. At this time, extraction of hydrochloric acid using TEHA is preferably performed in two or more stages in order to increase the extraction rate.

The step (S90) of removing the extracted hydrochloric acid (HCl) is a step of removing hydrochloric acid (HCl) from the hydrochloric acid (HCl) extract and regenerating the extractant TEHA. Distilled water can be used for the removal.

Hereinafter, the present invention will be described in detail based on preferred embodiments of the present invention. However, it should be understood that the present invention is not limited to the following preferred embodiments. Various modifications can be made by those skilled in the art But should be understood to include examples.

Waste catalyst  Leaching

The spent catalyst used in the examples of the present invention is a Mo / Co-Al ₂ O ₃ catalyst used in a petrochemical process. The spent catalyst was washed with acetone and dried at about 80 ° C for 12 hours.

Although the shape of the spent catalyst is a cylindrical shape, it was made into powders having a size range of 50 to 250 μm through pulverization and classification, and then the leaching efficiency was measured according to the particle size through a preliminary test. However, The difference in leaching rate was insignificant. The following leaching was carried out with particles having an average particle size of 250 mu m.

The waste catalyst particles used in the examples of the present invention were examined for chemical components using XRF and ICP-AES, and the results are shown in Table 1 below.

Mo Co Ni Fe Si Al 8.1 wt% 2.5 wt% 0.02 wt.% 0.03 wt.% 0.01 wt% 44.5 wt.%

As shown in Table 1, the waste catalysts used in the examples of the present invention mainly include molybdenum, cobalt and aluminum, and nickel, iron and silicon were contained in an extremely small amount. On the other hand, vanadium (V) was not detected at all, which appears to have vanadium (V) removed in the washing process.

2 shows the results of measurement of the leaching rates of the valuable metals (Mo, Co, Al, Fe, Ni, and Si) according to the concentration of hydrochloric acid and the leaching time at room temperature. 2B shows the case where the hydrochloric acid concentration is 2 mol / L, FIG. 2C shows the case where the hydrochloric acid concentration is 3 mol / L, and FIG. 2D shows the case where the hydrochloric acid concentration is 4 mol / L . The leaching rate was 5 wt.% S / L.

As can be seen from Figs. 2A to 2D, the leaching time does not greatly affect the leaching rate of the valuable metal, and the leaching rate tends to saturate with leaching time of 1 hour or more. Therefore, the leaching time is preferably 1 hour or more.

As the concentration of hydrochloric acid increased from 1 mol / L to 4 mol / L, the leaching rate of molybdenum (Mo) increased from 55.7% to 70%, while the leaching rate of cobalt (Co) increased from 81.2% to 68% Respectively. On the other hand, the leaching rate of aluminum (Al), iron (Fe) and nickel (Ni) was very low, less than 10%, and the leaching rate of silicon (Si) was about 20 to 50%. Since the leaching rates of molybdenum (Mo) and cobalt (Co) are similar at a concentration of hydrochloric acid of 2 to 4 mol / L, the concentration of hydrochloric acid is preferably 2 to 4 mol / L and from 2 to 3 mol / It is advantageous.

FIG. 3 shows the results of measuring the difference in leaching rate depending on the change in leaching temperature (25 ° C. to 110 ° C.) when leaching using 2 mol / L hydrochloric acid and 3 mol / L hydrochloric acid.

As shown in FIG. 3, the leaching rate of the metal-rich metal increases as the temperature increases. The maximum leaching rate at 110 ° C is 79% for molybdenum (Mo) at 3 mol / L of hydrochloric acid, And 88.6% respectively. Therefore, it can be seen that the concentration of hydrochloric acid is more advantageous than 3 mol / L of 2 mol / L.

Fig. 4 shows the result of evaluating the leaching rate according to the leaching ratio. The leaching time was 1 hour, the leaching temperature was 90 ℃, and the hydrochloric acid concentration was 3 mol / L. As can be seen in Fig. 4, the leach rate decreases as the ratio of the high liquid amount increases, so that the pulp density is preferably 5 wt%.

From the above results, leaching of waste catalyst was performed under the following conditions.

Leaching temperature 90 ° C Reaction time 1 hours Waste Catalyst Particle Size 0.25 mm Pulp density 5 wt.% S / L Hydrochloric acid concentration 3 mol / L

Specifically, the leaching reaction was carried out by adding hydrochloric acid to a sealed vessel (500 mL), heating the leachate to a reaction temperature of 90 ° C while stirring at 300 rpm, adding waste catalyst powder, and stirring for 1 hour.

After the leaching reaction, the undissolved residues were separated by using a vacuum filter. The components of the leaching solution except for the non-dissolved residues were measured using ICP-OES. The chemical composition of the leached solution Were as shown in Table 3 below.

HCl (M) Mo (g / L) Co (g / L) Al (g / L) 3 3.9 1.175 18.9

As can be seen from Table 3, molten aluminum (Mo) and cobalt (Co) contained impurities in a small amount of aluminum (Al), silicon (Si) and nickel (Ni) .

Extraction and recovery of molybdenum (Mo)

In the embodiment of the present invention, TBP (99% of tri-n-butyl phosphate, available from Yakurin Chemical Industry Co., Ltd.) and an organic solvent containing kerosene as a diluent were used for selective extraction of molybdenum (Mo) contained in the hydrochloric acid leaching solution.

5 shows the extraction rates of the valuable metals (Mo, Co, Al) according to the concentration of TBP. As shown in FIG. 5, molybdenum (Mo) exhibits an extraction rate of almost 100% at a TBP concentration of 0.5 mol / L or more, and thereafter, the extraction rate does not change even when the TBP concentration is increased. Therefore, the concentration of TBP is preferably 0.5 mol / L or more.

Since the TBP extracted from molybdenum (Mo) is easily removed with diluted hydrochloric acid, the extraction of molybdenum (Mo) through TBP enables the recovery of molybdenum (Mo) to be carried out economically.

In the embodiment of the present invention, molybdenum (Mo) extracted with TBP can be completely removed even with 0.1 M dilute hydrochloric acid, and TBP from which molybdenum (Mo) has been removed is recycled for extraction of molybdenum (Mo).

Extraction and recovery of cobalt (Co)

Cobalt (Co) was extracted from the extracted raffinate of molybdenum by recovering molybdenum (Mo) using Alamine 308 and an organic solvent containing kerosene as a diluent.

FIG. 6 shows the extraction rates of the valuable metals (Co and Al) and hydrochloric acid (HCl) according to the concentration of Alamine 308 (0.1 to 2 mol / L). As shown in FIG. 6, the range in which a large amount of cobalt (Co) can be extracted is the case where the concentration of Alamine 308 is 0.5 mol / L or more, and the extraction rate of cobalt is kept almost constant at this point. On the other hand, the extraction rate of hydrochloric acid (HCl) tends to increase greatly from 1.5% to 64% as the concentration of Alamine 308 increases from 0.1 mol / L to 2 mol / L. In contrast, the extraction rate of aluminum (Al) is almost negligible. Also, as the concentration of Alamine 308 increases, the possibility of the appearance of the third phase increases. Therefore, it is desirable to keep the concentration of Alamine 308 as low as possible. On the other hand, an inhibitor such as 1-decanol may be added to inhibit the third phase, and 7.5% of 1-decanol was used in the examples of the present invention.

The concentration of Alamine 308 is preferably kept as low as 0.1 to 1.0 mol / L, and more preferably, the concentration of Alamine 308 is 0.1 to 0.5 mol / L.

In order to inhibit the extraction of hydrochloric acid and the formation of the third phase, extraction with Alamine 308 at a concentration of 0.1 mol / L makes it difficult to extract once, so the extraction isotherm plot ), And the results are shown in Fig. 7 shows the extraction isotherm curves for cobalt extraction using Alamine 308 under predetermined test conditions (2.9 mol / L hydrochloric acid leach solution, Alamine: 0.1 mol / L, diluent: kerosene, A / O ratio: extraction isotherm plot. As shown in FIG. 7, the extraction rate of cobalt was 99.8% and the loss ratio of hydrochloric acid was only about 3.4%. Therefore, even if the concentration of Alamine 308 is kept as low as 0.1 mol / L, the cobalt can be recovered at a high recovery rate.

Thus, Alamine 308 from which cobalt is extracted is easily removed through acidic distilled water maintained at pH 1.0.

Extraction and recovery of hydrochloric acid (HCl)

From the extracted raffinate of cobalt through the above-mentioned recovery process of cobalt (Co), hydrochloric acid (HCl) was extracted using TEHA and an organic solvent containing kerosene as a diluent and regenerated for leaching.

Figure 8 shows the extraction rate of hydrochloric acid according to the concentration change of TEHA (0.1 ~ 1.5 mol / L). As shown in FIG. 8, when the TEHA concentration was increased from 0.1 mol / L to 1.5 mol / L, the extraction ratio of hydrochloric acid increased from 4.8% to 48.7%. At this time, aluminum was not extracted with TEHA.

9 is a graph showing the isothermal extraction curves for determining the number of stages in which a large amount of hydrochloric acid can be extracted. / A ratio: 1 ~ 6) is the McCabe-Thiele plot when hydrochloric acid is extracted using TEHA. The extraction was carried out at constant temperature and volume.

As shown in FIG. 9, it was found that most of the hydrochloric acid could be extracted through the two stages at the A / O ratio of 0.5, and hydrochloric acid was extracted from the two stages through the two stages. As a result, hydrochloric acid was extracted at an extraction rate of 96.4% .

Distilled water was used to remove hydrochloric acid from TEHA from which hydrochloric acid was extracted.

10 shows a McCabe-Thiele plot of a process of removing hydrochloric acid from TEHA under predetermined test conditions (TEHA: 1.35 mol / L, diluent: kerosene, detergent: distilled water, O / A ratio: 1 to 7).

As the A / O ratio increased from 1 to 3, the removal rate of hydrochloric acid was 52.7%. The removal rate of hydrochloric acid was affected by the aspect ratio of the water / organic phase. To 95.5%. From this, it can be seen that the removal of hydrochloric acid using TEHA allows the removal of most hydrochloric acid from the A / O ratio of 0.5 to 2 stages. Through this process, the concentration of actually removed hydrochloric acid was 0.01 mol / L and showed a removal rate of 99.2%.

As described above, according to the method of the present invention, valuable metals such as molybdenum (Mo) and cobalt (Co) can be recovered from the leached solution of the spent catalyst at low cost, and hydrochloric acid ) Can be recycled at a high level, which can greatly reduce the cost of recovering valuable metals.

Claims (13)

(a) contacting molten catalyst leached with hydrochloric acid with a first organic solvent containing TBP (Tri-n-butyl Phospate) to selectively extract molybdenum;
(b) removing molybdenum from the molybdenum-extracted first organic solvent using an aqueous hydrochloric acid solution;
(c) contacting the extraction filtrate from which the molybdenum is extracted with a second organic solvent containing Alamine 308 ((Tri-iso-octyl Amine) to selectively extract cobalt from the second organic solvent;
(d) removing cobalt from the second organic solvent from which the cobalt has been extracted using an aqueous hydrochloric acid solution. The method according to claim 1,
Wherein the spent catalyst leach solution is a solution of spent catalyst dissolved in hydrochloric acid. 3. The method of claim 2,
(e) contacting the extracted filtrate from which cobalt is extracted with a third organic solvent to extract the hydrochloric acid into the third organic solvent,
(f) removing the hydrochloric acid from the third organic solvent from which the hydrochloric acid has been extracted. delete delete The method of claim 3,
Wherein the third organic solvent comprises TEHA (tri 2-ethyl hexyl amine). delete The method according to claim 1,
Wherein the first organic solvent comprises TBP (Tri-n-butyl Phospate) and kerosene, and the TBP concentration is 0.5 mol / L or more. The method according to claim 1,
The second organic solvent comprises Alamine 308 (Tri-iso-octyl Amine) and kerosene, and the concentration of Alamine 308 (Tri-iso-octyl Amine) is in the range of 0.1 mol / L to 0.5 mol / A method for recovering valuable metals from an extract. The method according to claim 6,
Wherein the third organic solvent comprises tri-ethyl hexyl amine (TEHA) and kerosene, and the extraction is performed in two or more stages. 4. The method according to any one of claims 1 to 3,
Wherein the second organic solvent further comprises a modifier for inhibiting the formation of the third phase. 12. The method of claim 11,
Wherein the reforming agent is 1-decanol. The method of claim 3,
The removal of the step (f) is performed by distilled water.

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