TWI542701B - Method for soaking metal in waste catalyst by acid liquid - Google Patents

Description

Method for leaching metal contained in waste catalyst by acid

The invention relates to a method for recovering metal from a waste catalyst, in particular to a method for acid leaching the metal contained in the waste catalyst produced by the hydrodesulfurization process and recycling the heavy oil therein.

In the petroleum refining industry, the catalyst for the hydrodesulfurization process of petroleum is mostly based on alumina, and then the active metal such as vanadium, molybdenum or nickel or its oxide is fixed to the carrier. surface. However, when the catalyst adsorbs a large amount of iron, phosphorus and other elements in the catalytic process, it will cause the catalyst to fail and form a so-called RDS or HDS waste catalyst. Such RDS or HDS waste catalyst may cause serious damage if it is not effectively treated. Environmental poisoning.

In fact, the RDS waste catalyst used to treat heavy oil is rich in vanadium, molybdenum, nickel, aluminum and heavy oil. The HDS waste catalyst produced by treating diesel oil is rich in molybdenum, nickel, aluminum and heavy oil. . Therefore, these waste catalysts still have the value of reprocessing for most operators.

At present, most of the sodium-based roasting method is used as an effective treatment for the waste catalyst. In addition to the heavy oil contained in the waste catalyst, the vanadium, molybdenum, nickel and other metals contained therein can be recovered.

However, the time-consuming and high-temperature of the roasting process not only consumes energy and causes a burden of processing costs, but also makes it impossible to comprehensively recover various metals, and the overall recovery efficiency does need to be further improved. Secondly, if it is used to treat RDS waste catalysts containing a large amount of heavy oil, it is easy to burn heavy oil at high temperature, and the sulfur or its compound dissolved in the heavy oil will be dispersed in the air. in this way As a result, not only can the heavy oil in the time-consuming and energy-consuming roasting process be recycled and reused, but it also has serious air pollution problems.

In view of this, it is indeed necessary to develop a novel effective treatment method for waste catalyst for use in the RDS or HDS waste catalyst produced by the hydrodesulfurization process, thereby solving various problems as described above.

The main object of the present invention is to improve the above disadvantages to provide a method for leaching the metal contained in the waste catalyst by acid, which is capable of comprehensively recovering the metal contained therein, and simultaneously recovering and reusing the rich heavy oil directly to reduce the consumption. Can reduce and reduce environmental pollution concerns.

A second object of the present invention is to provide a method for leaching a metal contained in a spent catalyst by acid, which is capable of directly decanting the metal in an oxidized state to reduce the difficulty of subsequent treatment and to enhance the metal pouring rate.

In order to achieve the foregoing object, the present invention uses a method for acid leaching a metal contained in a spent catalyst to treat a waste catalyst produced by a hydrodesulfurization process, comprising: a leaching step, the waste contact The medium mixture is immersed in a highly oxidizing acid liquid, so that the sulfur in the mixture reacts with the acid liquid to produce a mixed liquid containing the heavy oil, the decanting liquid and the residue body, and the decanting liquid And the residue body is rich in oxidized metal, wherein the waste catalyst mixture is an RDS waste catalyst or the RDS waste catalyst mixed HDS waste catalyst, and the RDS waste catalyst or the mixed waste catalyst Rich in vanadium, molybdenum, nickel, aluminum and heavy oil, the highly oxidizing acid is nitric acid, hypochlorous acid, chloric acid, chlorous acid, perchloric acid, nitrous acid or concentrated sulfuric acid, in the leaching step Further adding an auxiliary acid, and the auxiliary acid is hydrochloric acid or sulfuric acid; and a degreasing step, moving from the mixed liquid After the residue is removed, the decanted liquid and the heavy oil are layered to filter the heavy oil by oil separation to obtain the decanted liquid; and a refining step is performed to leaching the metal in the residue. Obtaining a residue leaching solution for extracting and depositing the metal contained in the leaching solution and the residue leaching solution respectively, the refining step further comprising a first extraction step and a second extraction step, wherein the first extraction step is Extracting and depositing a large amount of vanadium, nickel and a small amount of aluminum and molybdenum in the decanting liquid, and the second extraction step immersing the residue body in an alkali solution to generate the residue leachate, and then from the residue leach solution Extracting and depositing molybdenum and generating a large amount of aluminum slag, the first extraction step and the second extraction step are first co-extracting the decanted liquid with an extractant to obtain a total extraction solution, and then using an alkaline solution or The acid solution is back-extracted to obtain a stripping solution, and then the stripping solution is used to precipitate the metal contained in the extract.

The concentration of the auxiliary acid added to the acid solution is 1 to 50% by weight.

Wherein, the relative weight ratio (acid solution/mixture) of the acid liquid to the mixed material is 1 to 4. Further, the concentration of the highly oxidizing acid liquid is 5 to 40%.

Wherein, the second extraction step directly soaks the residue body in an alkali solution, so that the molybdenum contained in the residue body is poured into the residue leaching solution, and the residue leaching solution is extracted according to the first extraction step to sink the residue. Contains metal.

The lye may be a solution of sodium carbonate, sodium hydroxide or sodium chloride. The extractant may be selected from the group consisting of N-235, Alamine 336, Aliquit 306, P204, P507, N236, and TOA. Further, the alkaline solution for extraction is ammonia water, sodium hydroxide, sodium chloride or sodium carbonate, and the acidic solution for extraction is sulfuric acid, hydrochloric acid, phosphoric acid or perchloric acid.

Moreover, the method for leaching the metal contained in the waste catalyst by acid is used for treating a waste catalyst generated by the hydrodesulfurization process, comprising: a leaching step, soaking the waste catalyst mixture In a highly oxidizing acid liquid, the sulfur in the mixture is reacted with the acid liquid to produce a mixed liquid containing heavy oil, decanting liquid and residue body, and the decanting liquid and the residue are rich in the body Containing an oxidized metal, wherein the waste catalyst mixture is a HDS waste catalyst, and the HDS waste catalyst is rich in molybdenum, nickel, aluminum and heavy oil, and the highly oxidizing acid is nitric acid, Chloric acid, chloric acid, chlorous acid, perchloric acid, nitrous acid or concentrated sulfuric acid, another auxiliary acid is added in the leaching step, and the auxiliary acid is hydrochloric acid or sulfuric acid; a degreasing step, from the mixed liquid After removing the residue body, the layered liquid and the heavy oil are layered to filter the heavy oil by oil separation to obtain the decanting liquid; and a refining step, the metal in the residue body Leaching to obtain a residue leaching solution to extract and precipitate both from the decanting liquid and the residue leaching solution Metal-containing, the refining step further comprises a first extraction step and a second extraction step, the first extraction step extracting and depositing a large amount of nickel and a small amount of aluminum and molybdenum from the decanting liquid, and the second extraction The step of immersing the residue in an alkali solution to form the residue leaching solution, extracting and depositing molybdenum from the residue leaching solution and generating a large amount of aluminum slag, the first extraction step and the second extraction step are first An extractant co-extracts the decanted liquid to obtain a co-extracted solution, and then extracts the co-extracted solution with an alkaline solution or an acidic solution to obtain a stripping solution, and then the stripping solution The liquid precipitates the metal contained in the decanted liquid.

The concentration of the auxiliary acid added to the acid solution is 1 to 50% by weight.

Wherein the relative weight ratio of the acid to the mixture (acid/mix) is 1 To 4. Further, the concentration of the highly oxidizing acid liquid is 5 to 40%.

Wherein, the second extraction step directly soaks the residue body in an alkali solution, so that the molybdenum contained in the residue body is immersed in the residue leaching liquid, and the residue leaching liquid is extracted according to the first extraction step to sink the contained metal.

The lye may be a solution of sodium carbonate, sodium hydroxide or sodium chloride. The extractant may be selected from the group consisting of N-235, Alamine 336, Aliquit 306, P204, P507, N236, and TOA. Further, the alkaline solution for extraction is ammonia water, sodium hydroxide, sodium chloride or sodium carbonate, and the acidic solution for extraction is sulfuric acid, hydrochloric acid, phosphoric acid or perchloric acid.

The above and other objects, features and advantages of the present invention will become more <RTIgt; It is a RDS or HDS waste catalyst produced after the hydrodesulfurization process (collectively referred to as a waste catalyst mixture in the present invention), and the RDS waste catalyst is rich in vanadium, molybdenum, nickel, aluminum. And heavy oil, HDS waste catalyst is rich in molybdenum, nickel, aluminum and heavy oil, and the waste catalyst mixture can also be RDS waste catalyst mixed HDS waste catalyst.

Referring to FIG. 1, which is a preferred embodiment of the present invention, the method for acid leaching the metal contained in the spent catalyst comprises an acid leaching step S1, a degreasing step S2, and a refining step S3. Wherein, the product properties according to the acid leaching and degreasing can be selected in the refining step S3 for appropriate treatment, which will be described in detail later.

The leaching step S1 is to soak the waste catalyst mixture in a high oxidation property. In the acid liquid, the sulfur in the waste catalyst mixture is reacted with the acid liquid to produce a mixed liquid containing heavy oil, decanting liquid and residual body, and the decanting liquid and the residue are rich in the body Oxidized metal. Among them, the acid liquid system may select a highly oxidizing acidic liquid such as nitric acid, hypochlorous acid, chloric acid, chlorous acid, perchloric acid, nitrous acid, concentrated sulfuric acid, or the like.

In addition, the present invention further adds an auxiliary acid in the leaching step S1, and the acid value of the acid solution is lowered by the auxiliary acid to increase the metal pouring rate of the mixture immersed in the acid solution. The auxiliary acid may be selected from a strongly acidic solution such as hydrochloric acid or sulfuric acid, and the concentration of the auxiliary acid added to the acid solution is preferably from 1 to 50% by weight.

In particular, the highly oxidizing acid solution will sulphurize with the sulfur in the waste catalyst mixture, and the waste catalyst mixture immersed in the acid solution will be accompanied by a vulcanization reaction, and a large amount of acid is dissolved. Vanadium, nickel and a small amount of aluminum, molybdenum metal, and through the high oxidation characteristics of the acid, vanadium, molybdenum, nickel, aluminum and unreacted sulfur element are converted into an easily extractable oxidation state by oxidation reaction. Therefore, the mixed liquid produced by the acid treatment produces a decanted liquid and a residue body rich in the oxidized metal in addition to the heavy oil remaining. Moreover, the pour liquid has a large amount of vanadium, nickel and a small amount of aluminum and molybdenum, and the residue body has a large amount of aluminum slag and molybdenum.

In particular, in the leaching step S1, a sulfur-containing compound and a vapor compound are also formed by the sulfurization reaction. Wherein, the vaporized product can be re-reacted into the highly oxidizing acid to be reused in the leaching step S1. In detail, the vaporized product is an oxidized acid radical formed by oxidation of the acid solution, so that it can be re-reacted with water to form the acid liquid for reuse in the leaching step S1; The compound can also lower the pH of the acid solution. In order to enhance the metal pouring effect of the waste catalyst mixture in the acid solution.

Please refer to FIG. 1 again, the mixed liquid produced by the leaching step S1 includes heavy oil, decanted liquid and residue body. In order to avoid the heavy metal affecting the subsequent metal extraction effect and can directly recycle and reuse the heavy oil, it is selected. The degreasing step S2 is operated after the leaching step S1.

The degreasing step S2 removes the residue from the mixed solution, and waits for the decanted liquid to form a layer with the heavy oil to filter out the heavy oil by oil separation to obtain the decanted liquid. In detail, when the residue body is separated from the mixed liquid by a sieve, since the decanted liquid and the heavy oil each have different specific gravities, the heavy oil can be easily passed through the gravity flow method by utilizing the difference in the specific gravity of the two. Separate. In this way, the heavy oil can be recycled and reused, and the time and energy consumed by the conventional high-temperature combustion are eliminated; in addition, the residue which is separated first and the decanted liquid which does not contain heavy oil can be further purified in the subsequent step S3. According to the different attributes of the two, the appropriate way is selected to propose the metal contained in it, so that the metal can be recycled and reused comprehensively.

The purification step S3 is performed by leaching the metal in the residue to obtain a residue leaching solution for extracting and depositing the metal from the decanting liquid and the residue leaching solution, respectively. In detail, since a large amount of vanadium, nickel and a small amount of aluminum and molybdenum contained in the waste catalyst mixture have been poured into the decanting liquid after the leaching step S1, the decanting liquid may be selected directly. Some of the metal is extracted and precipitated; however, a large amount of aluminum and molybdenum remaining in the residue are leached out of the molybdenum by the alkali solution, and then extracted to precipitate the molybdenum.

In this embodiment, the refining step S3 may further include a first extracting step S31 and a second extracting step S32 as shown in FIG. 2 .

The first extraction step S31 extracts and precipitates a large amount from the decanted liquid Vanadium, molybdenum, nickel and a small amount of aluminum, molybdenum. In detail, the first extraction step S31 is first co-extracting the vanadium and molybdenum metal in the decanting liquid with an extracting agent to obtain a total extraction liquid, and then using an alkaline solution or an acidic solution. The extract is subjected to stripping, and after obtaining a stripping solution, vanadium and molybdenum are separately precipitated by the stripping solution to obtain recovered vanadium and molybdenum metal; then, a residual liquid of vanadium and molybdenum metal is extracted. After the calcium is removed by calcium carbonate, calcium sulfate can be produced, and the pH is adjusted to 7-8 to obtain a nickel-aluminum concentrate by hydrolysis. Wherein, the extracting agent may be selected from the group consisting of N-235, Alamine 336, Aliquil 306, P204, P507, N236 and TOA; the alkaline solution for extraction may be ammonia water, sodium hydroxide, sodium chloride or sodium carbonate. Etc. The acidic solution for extraction may be sulfuric acid, hydrochloric acid, phosphoric acid or perchloric acid.

The second extraction step S32 is performed by immersing the residue in an alkali solution to form the residue leaching solution, and extracting and depositing molybdenum and a large amount of aluminum slag from the residue leaching solution. In detail, the second extraction step S32 directly soaks the residue body in an alkali solution so that the molybdenum contained in the residue is immersed in the residue leaching solution; and then, the same technique as the first extraction step S31 is utilized. Means extracting the residue leachate and depositing molybdenum therein. The lye may be a solution of sodium carbonate, sodium hydroxide or sodium chloride.

In particular, in the first extraction step S31 and the second extraction step S32, the technical means for precipitating vanadium, molybdenum, nickel or aluminum by extraction and stripping can be easily understood by those skilled in the art, and is not The main technical features of the invention are located, so the details are not described in detail herein.

In summary, the present invention not only leaches vanadium, molybdenum, nickel and aluminum contained in the waste catalyst mixture through a highly oxidizing acid liquid, but also makes vanadium, molybdenum, nickel and Aluminum is converted into an easily extractable oxidation state by the high oxidation of the acid to reduce the difficulty of subsequent extraction and precipitation of the metal, thereby improving the metal pouring rate and recycling the metal comprehensively. In addition, by increasing the metal pouring rate by the present invention, it is also possible to directly use the difference in specific gravity of the material to filter out the heavy oil carried by the waste catalyst mixture by means of oil separation, in particular, selecting the treatment of the present invention. When a large amount of heavy oil RDS waste catalyst is used, it is possible to recycle and reuse a large amount of heavy oil to produce new economic value. In this way, not only the energy consumption and time consumption of traditional heavy oil burning can be saved, but also the sulfur dissolved in the heavy oil or its compound can be prevented from being dispersed in the air due to combustion, so as to further solve the problem of air pollution and achieve the reduction. The effect of environmental pollution.

In order to prove that the present invention can effectively separate heavy oil to avoid the effect of heavy oil on the pouring effect, and further improve the pour rate of vanadium, molybdenum, nickel and aluminum metal, the present embodiment uses nitric acid as the main acid leaching system, and Taking the RDS waste catalyst as an example, the following experimental analysis was performed.

In a specific embodiment of the present invention, 1000 g of the RDS waste catalyst is immersed in a nitric acid solution having a concentration of 20%, and the relative weight ratio (nitrate/mixture) of the nitric acid solution to the mixture is adjusted to be 1 to 4, respectively. Reaction for 4 hours. Herein, the chemically vaporized nitrogenate is first collected by a pumping device, and the nitric acid is produced by the chemical formula 2 in the above reaction.

HO-NO ₂ +2H ₂ SO ₄ →NO ₂ ⁺ +2H ₂ SO ₄ ^- +H ₃ O ⁺ [Chemical Formula 1]

NO ₂ ⁺ +H ₂ O→HNO ₃ [Chemical Formula 2]

After the metal contained in the decanting liquid and the residue body is separately precipitated, the final tailings are analyzed to determine the content of vanadium, molybdenum, nickel and aluminum in the tailings, as shown in Table 1. .

Table 1: Metal content measured at different nitric acid/mixing ratios.

It can be seen from Table 1 that when the relative weight ratio of the nitric acid solution to the mixture (nitrogen:mixture) is higher than 2:1, the recovery of the vanadium, molybdenum and nickel metal can be as high as 99% or more.

In a second embodiment of the present invention, 1000 g of the RDS waste catalyst is immersed in a nitric acid having a concentration of 5 to 40% under the condition that the relative weight ratio of the nitric acid solution to the mixture (nitrogen:mixing) is 3:1. The solution is reacted for 4 hours each, and after the metal contained in the decanting liquid and the residue body is separately precipitated, the final tailings are analyzed to determine vanadium, molybdenum, nickel and aluminum in the tailings. The content of metal is detailed in Table 2.

It can be seen from Table 2 that when the concentration of nitric acid is higher than 10%, the recovery rate of the vanadium, molybdenum and nickel metal can be as high as 99% or more.

Therefore, it is confirmed from Table 1 and Table 2 that the nitric acid-based acid leaching system of the present invention can improve the recovery efficiency of the vanadium, molybdenum and nickel metal without being affected by heavy oil, so as to be low in energy consumption and low in energy consumption. In a time-consuming manner, the full recovery of the metal in the RDS waste catalyst is achieved.

In addition, Tables 1 and 2 show that the final tailings have up to 90-95% of aluminum, so it is confirmed that the vanadium, molybdenum and nickel metal are not subjected to the simultaneous dumping of aluminum, and can ensure the inclination. The quality of the metal after the out. Even after immersing the RDS waste catalyst with the nitric acid, the sulfur measured in the tail slag is less than 2%, and it is known that most of the sulfur contained in the RDS waste catalyst is converted into sulfuric acid by nitric acid. And remixed in the acid.

In addition to the above, in the third embodiment of the present invention, 1000 g of the RDS waste catalyst is immersed in a concentration of 20% under the condition that the relative weight ratio of the nitric acid solution to the mixture (nitrogen:mixing) is 3:1. a nitric acid solution, and additionally adding 1 to 25% of a strong acid (such as hydrochloric acid) to react for 4 hours, and after the reaction is completed, the decanted liquid after the leaching is analyzed to determine the final vanadium, molybdenum, and nickel. And the recovery rate of aluminum metal is detailed in Table 3.

It is known from Table 3 that when a strong acid is assisted in the nitric acid leaching system, Among them, the leaching recovery effect of the vanadium, molybdenum and nickel metal is significantly improved. Thereby, it is confirmed that the addition of the auxiliary acid (such as strong acid such as hydrochloric acid or sulfuric acid) can effectively improve the recovery rate of the vanadium, molybdenum and nickel metal.

According to the above method, the method for acid leaching the metal contained in the waste catalyst can completely recover the metal contained therein, and at the same time directly recover and reuse the rich heavy oil to reduce the energy consumption and reduce the environmental pollution. . Moreover, in the method of acid leaching the metal contained in the waste catalyst, the metal can be directly decanted in the oxidation state to reduce the difficulty of subsequent treatment, thereby achieving the effect of improving the metal pouring rate.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

〔this invention〕

S1‧‧‧ leaching step

S2‧‧‧Degreasing step

S3‧‧‧ refining steps

S31‧‧‧First extraction step

S32‧‧‧Second extraction step

Figure 1 is a flow chart 1 of the operation of the present invention.

Figure 2: Flow chart 2 of the operation of the present invention.

S1‧‧‧ leaching step

S2‧‧‧Degreasing step

S3‧‧‧ refining steps

Claims (16)

The invention relates to a method for leaching a metal contained in a waste catalyst by acid, which is used for treating a waste catalyst produced by a hydrodesulfurization process, comprising: a leaching step, immersing the waste catalyst mixture in a high In the oxidizing acid solution, the sulfur in the mixture is reacted with the acid liquid to produce a mixed liquid containing the heavy oil, the decanting liquid and the residue body, and the decanting liquid and the residue are rich in oxidation. The metal catalyst, wherein the waste catalyst mixture is an RDS waste catalyst or the RDS waste catalyst mixed HDS waste catalyst, and the RDS waste catalyst or the mixed waste catalyst is rich in vanadium and molybdenum Nickel, aluminum and heavy oil, the highly oxidizing acid is nitric acid, hypochlorous acid, chloric acid, chlorous acid, perchloric acid, nitrous acid or concentrated sulfuric acid, and an auxiliary acid is additionally added in the leaching step, and The auxiliary acid is hydrochloric acid or sulfuric acid; after removing the residue from the mixed liquid, a degreasing step is performed, and the decanted liquid and the heavy oil are layered to be separated, and the heavy oil is filtered by oil separation. And the decanting liquid; and a refining step, leaching the metal in the residue to obtain a residue leaching solution Extracting and depositing the metal contained in the leachate and the residue leachate, the refining step further comprising a first extraction step and a second extraction step, the first extraction step is extracted from the decanted liquid A large amount of vanadium, nickel and a small amount of aluminum and molybdenum are deposited, and the second extraction step is performed by immersing the residue in an alkali solution to form the residue leaching solution, and extracting and depositing molybdenum from the residue leaching solution and generating a large amount of aluminum slag, the first extraction step and the second extraction step are first co-extracting the decanted liquid with an extractant to obtain a total extraction solution, and then using an alkaline solution Or the acid solution is back-extracted to obtain a stripping solution, and then the stripping solution is used to precipitate the metal contained in the extract. The method for acid leaching the metal contained in the waste catalyst according to the first aspect of the patent application, wherein the auxiliary acid is added to the acid solution in a concentration of 1 to 50% by weight. A method for acid leaching a metal contained in a spent catalyst according to the first or second aspect of the patent application, wherein the relative weight ratio of the acid to the mixture (acid/mix) is from 1 to 4. The method for acid leaching the metal contained in the waste catalyst according to the first or second aspect of the patent application, wherein the concentration of the highly oxidizing acid liquid is 5 to 40%. According to the method of claim 1, wherein the second extraction step directly soaks the residue in an alkali solution, so that the molybdenum contained in the residue is immersed in the residue. The residue is leached and the residue leaching solution is extracted according to the first extraction step to deposit the metal contained therein. A method for acid leaching a metal contained in a spent catalyst according to the fifth aspect of the patent application, wherein the alkali solution is a solution of sodium carbonate, sodium hydroxide or sodium chloride. A method for acid leaching a metal contained in a waste catalyst according to claim 1 or 5, wherein the extractant may be selected from the group consisting of N-235, Alamine 336, Aliquit 306, P204, P507, N236 and TOA. Group of. The method for acid leaching the metal contained in the waste catalyst according to the first or fifth aspect of the patent application, wherein the alkaline solution for the extraction is ammonia water, sodium hydroxide, sodium chloride or sodium carbonate, and The acidic solution for the extraction It is sulfuric acid, hydrochloric acid, phosphoric acid or perchloric acid. The invention relates to a method for leaching a metal contained in a waste catalyst by acid, which is used for treating a waste catalyst produced by a hydrodesulfurization process, comprising: a leaching step, immersing the waste catalyst mixture in a high In the oxidizing acid solution, the sulfur in the mixture is reacted with the acid liquid to produce a mixed liquid containing the heavy oil, the decanting liquid and the residue body, and the decanting liquid and the residue are rich in oxidation. The metal catalyst, wherein the waste catalyst mixture is HDS waste catalyst, and the HDS waste catalyst is rich in molybdenum, nickel, aluminum and heavy oil, and the high oxidation acid is nitric acid, hypochlorous acid, Chloric acid, chlorous acid, perchloric acid, nitrous acid or concentrated sulfuric acid, another auxiliary acid is added in the leaching step, and the auxiliary acid is hydrochloric acid or sulfuric acid; and a degreasing step is removed from the mixture After the residue body, the decanting liquid and the heavy oil are layered, and the heavy oil is filtered by oil separation to obtain the decanting liquid; and a refining step is performed to leaching the metal in the residue to obtain a residue leaching solution to extract and precipitate the gold contained in the leaching solution and the residue leaching solution respectively The refining step further comprises a first extraction step and a second extraction step, the first extraction step extracting and depositing a large amount of nickel and a small amount of aluminum and molybdenum from the decanting liquid, and the second extraction step is The residue body is immersed in an alkali solution to form the residue leaching solution, and the residue leaching solution extracts and deposits molybdenum and generates a large amount of aluminum slag. The first extraction step and the second extraction step are first extracted by an extraction process. The extract is co-extracted to obtain a total extract, and then the extract is back-extracted with an alkaline solution or an acidic solution, and after obtaining a stripping solution, the stripping solution is further The metal contained in the decanted liquid. A method for acid leaching a metal contained in a spent catalyst according to claim 9 of the patent application, wherein the auxiliary acid is added to the acid solution in a concentration of 1 to 50% by weight. A method for acid leaching a metal contained in a spent catalyst according to claim 9 or 10, wherein the relative weight ratio of the acid to the mixture (acid/mix) is 1 to 4. A method for acid leaching a metal contained in a spent catalyst according to claim 9 or 10, wherein the concentration of the highly oxidizing acid is 5 to 40%. According to the method of claim 9, wherein the second extraction step directly soaks the residue in an alkali solution, so that the molybdenum contained in the residue is immersed in the residue. The residue is leached and the residue leaching solution is extracted according to the first extraction step to deposit the metal contained therein. A method for acid leaching a metal contained in a waste catalyst according to claim 13 of the patent application, wherein the alkali solution is a solution of sodium carbonate, sodium hydroxide or sodium chloride. A method for acid leaching a metal contained in a waste catalyst according to claim 9 or 13 of the patent application, wherein the extractant may be selected from the group consisting of N-235, Alamine 336, Aliquit 306, P204, P507, N236 and TOA. Group of. a method for acid leaching a metal contained in a waste catalyst according to claim 9 or 13 of the patent application, wherein the alkaline solution for the extraction is ammonia water, sodium hydroxide, sodium chloride or sodium carbonate, and The acidic solution for the extraction is sulfuric acid, hydrochloric acid, phosphoric acid or perchloric acid.