TWI870808B - Method for recovering metal from waste catalyst using heating technology - Google Patents

Abstract

The present invention discloses a method for recovering metals from waste catalysts by using a heating technology. The process includes a step of performing a pulverization treatment on the waste catalyst to form a waste catalyst powder, a step of adding a strong acid to the waste catalyst powder to form a reaction solution, a step of placing the reaction solution in a high-pressure heating container for a heating reaction, a step of performing a liquid-slag separation, a step of performing a collection of a supernatant and a precipitated slag, and a step of separately precipitating different metals, so as to extract and recover metals such as nickel, cobalt, vanadium, etc. from waste catalyst slag containing nickel-cobalt concentrate.

Description

Method for recovering metal from waste catalyst using heating technology

The present invention relates to the technical field of recovering nickel and cobalt concentrate from waste catalysts, and specifically to a method of recovering metals from waste catalysts using heating technology, so as to effectively recover nickel and cobalt metal elements from waste materials to alleviate the supply crisis of nickel and cobalt metals.

According to the report, the global demand for precious metals has increased significantly in recent years. Precious metals mainly refer to gold, silver, and transition metals including cobalt, nickel, palladium, platinum, rhodium, ruthenium, nirconium, etc. Some transition metals such as nickel (Ni) and cobalt (Co) are widely used in metallurgy, chemical industry and battery industry and have wide application value. For example, the lithium-ion battery industry has been booming in recent years. According to the International Energy Agency (IEA), by 2030, 10% to 20% of the world's cars will be electric cars, reaching about 210 million to 250 million vehicles. Nickel metal is one of the important elements of the cathode material in lithium batteries. The demand for nickel is expected to increase several times. Therefore, if effective technology can be developed to recycle nickel metal elements from waste, it will alleviate the global nickel metal supply crisis.

In addition to its application in lithium batteries, nickel itself is also widely used in catalytic converters for cars and motorcycles. Since fuel oil for cars and motorcycles emits sulfur oxides after combustion, which causes air pollution, in order to reduce the sulfur oxides produced during combustion, various advanced countries have stipulated that oil refineries must reduce the sulfur content of diesel from the original 500ppm to 15ppm. Therefore, the oil industry has added the process of hydrodesulfurization (HDS) to the fuel manufacturing process to reduce pollution to the environment. The catalyst material required in the hydrodesulfurization process is generally formed from alumina (Al ₂ O ₃ ) colloid, which is dried and calcined to form a high-porosity, high-surface-area carrier, then immersed in a mixed solution of ammonium molybdate and cobalt nitrate, and then dried, calcined, and impregnated several times before being subjected to a sulfurization treatment. However, since the catalyst will absorb sulfur (S), carbon (C), vanadium (V), iron (Fe), molybdenum (Mo), nickel (Ni), cobalt (Co) and other trace elements during the hydrodesulfurization process, after long-term use, the accumulation of metal impurities and carbon deposition may cause the catalyst to become blocked and poisoned, that is, it no longer has the function of purifying exhaust gas and turns into solid waste. Therefore, it needs to be replaced and disposed of regularly. About 10,000 to 12,000 tons of waste hydrogenation desulfurization catalysts are produced each year in Taiwan, which contain many valuable metals adsorbed on the catalysts during the process, such as vanadium, molybdenum, and nickel. If the waste catalysts can be recycled, the thorny waste problem can be solved and the valuable metals can be recovered at the same time.

The above-mentioned waste catalyst slag containing nickel and other precious metals (blue sludge) is the residue obtained by alkaline roasting of hydrogen desulfurized waste catalyst (Co-Mo-Ni/Al ₂ O ₃ waste catalyst). At present, the annual production of blue sludge in Taiwan is about 7,000 tons. Due to the current inadequacy of technology and equipment of relevant industries, it is still mainly disposed of by landfill. However, Taiwan's land area is narrow, and legal sites for waste disposal are becoming increasingly difficult to obtain. Therefore, the resource recovery technology of waste catalyst containing nickel has become an urgent issue. Common technologies include the following: for example, Taiwan's Patent No. I295691 "Method for Recycling Waste Denitrification Catalyst", No. I401213 "Method for Recycling Nickel-Cobalt Concentrate from Waste Hydrogen Desulfurization Catalyst", No. I468524 "Method for Recovering Vanadium and Tungsten from Waste Selective Catalytic Reduction Catalyst" and U.S. Patent Nos. 4,657,745, 4,670,229, 5,445,728 and other patent cases disclose processes for recovering valuable metals from waste catalysts.

In summary, the above recycling methods and equipment have some problems and are not ideal. Some of them are too low in recovery rate, or too high in recovery cost due to high-temperature smelting energy consumption, and cannot be effectively economically applied. Therefore, most of them are currently transported to smelters for refining into nickel raw materials or stabilization and landfill treatment, which has the concern of polluting the environment. In other words, how to solve the above problems is what the industry expects and what the present invention intends to explore.

In view of the above shortcomings and needs, the inventor has used his many years of experience in related technologies and product design and manufacturing to research and create on the above topics, and actively seek solutions. After continuous efforts in research and trials, he finally successfully developed a method for recycling metals from waste catalysts using heating technology, thereby overcoming the shortcomings and deficiencies faced by existing technologies for recycling metals from waste catalysts.

Therefore, the main purpose of the present invention is to provide a method for recovering metals from waste catalysts using heating technology, so as to effectively recover precious metals from waste catalysts and significantly improve the recovery rate of precious metals.

In addition, another main purpose of the present invention is to provide a method for recycling metals in waste catalysts using heating technology, which can effectively reduce the energy consumption during recycling to achieve economic benefits of recycling.

In addition, another main purpose of the present invention is to provide a method for recovering metals in waste catalysts using heating technology, which can turn waste catalysts into resources to solve the problem of existing stable landfill treatment and overcome the concern of environmental pollution.

Based on this, the present invention mainly realizes the above-mentioned purpose and effect through the following technical means, and its process steps include: a pulverization treatment of waste catalyst is performed to form a waste catalyst powder; a strong acid is added to the waste catalyst powder to form a reaction solution: a specific weight of waste catalyst powder is added to a 3.5-4.5 times sulfuric acid strong acid liquid; a high-pressure heating container is placed to heat the reaction solution: the high-pressure heating container is placed in a heating system The system is heated and stirred to form a resource solution to be precipitated, the heating temperature is 150℃~220℃, and the stirring reaction time is 15min~150min; liquid-slag separation: the aforementioned resource solution to be precipitated is separated into liquid phase and solid phase to produce liquid supernatant and solid slag; the supernatant and slag are collected separately; and different metals are precipitated separately: the supernatant is added with a precipitant of corresponding concentration according to the metal to be precipitated, and the supernatant is separated and purified by a typical precipitation technology to recover the metal.

Thus, the present invention adds strong acid to the waste catalyst powder, places it in a high pressure autoclave for oil bath heating reaction, and then uses high-speed centrifugation to separate the liquid and solid phases. After collecting the supernatant of the liquid phase and the precipitate of the solid phase, the metal is extracted and precipitated from the supernatant to achieve the purpose of extracting and recovering metals from the waste catalyst slag containing nickel and cobalt concentrate. The extraction method provided by the present invention can effectively shorten the extraction recovery time and increase the recovery rate to more than 90%. At the same time, it can effectively reduce the energy consumption during recovery to achieve the economic benefits of recycling, and then the waste catalyst can be resourced to solve the problem of existing stable landfill treatment, thereby overcoming the concern of environmental pollution and effectively improving its economic benefits.

The present invention further achieves the aforementioned purpose and effect by using the following technical means; which include: Preferably, the waste catalyst powder in the step of adding the waste catalyst powder to a strong acid to form a waste catalyst powder of a reaction solution is formed by drying, grinding and sieving, and the particle size of the waste catalyst powder meets the range of ASTM sieve number #50~#200.

Preferably, in the step of adding the aforementioned waste catalyst powder to a strong acid to form a solution to be reacted, the weight ratio of the waste catalyst powder to the strong acid liquid is 1:3.8~4.2.

Preferably, the strong acid liquid can be obtained from concentrated sulfuric acid (H ₂ SO ₄ ).

Preferably, the high-pressure heating container in the step of placing the aforementioned solution to be reacted into a high-pressure heating container for heating reaction can be a high-pressure autoclave.

Preferably, the heating temperature in the step of placing the aforementioned solution to be reacted in a high-pressure heating container for heating reaction is 180°C to 220°C, and the stirring reaction time is 60min to 120min.

Preferably, in the step of placing the aforementioned solution to be reacted into a high-pressure heating container for heating reaction, the high-pressure heating container is placed in a heating system using a silicone oil bath for heating and stirring.

Preferably, the step of performing liquid-slag separation utilizes high-speed centrifugation to separate the liquid-slag.

Preferably, in the step of separately precipitating different metals, the supernatant is added with extractants of corresponding concentrations according to the metals to be extracted and precipitated, and the supernatant is separated and purified by extraction technology to recover the metals.

Preferably, in the step of precipitating different metals separately, dialkylphosphonic acid (CYANEX272) with a concentration of at least 20% can be added to the supernatant as an extractant, and the supernatant can be extracted, separated, purified, and recovered to obtain nickel and cobalt, and stripped using sulfuric acid to adjust the pH to 3.0-5.0 to form a nickel sulfate solution. For the recovery of cobalt, sulfuric acid with a concentration of at least 4M is used to adjust the pH to 0-1 to form a cobalt sulfate solution.

In order to enable the review committee to further understand the structure, features and other purposes of the present invention, the following are some preferred embodiments of the present invention, and are described in detail with the help of drawings, so that those familiar with the technical field can implement them in detail.

Figure 1: Schematic diagram of the process steps of the best embodiment of the method of recovering metals from waste catalysts using heating technology according to the present invention.

Figure 2: The nickel metal concentration diagram of the hydrothermal extraction at different temperatures and times in the method of recovering metals from waste catalysts using heating technology in the present invention.

The present invention is a method for recovering metal from waste catalysts using heating technology. The technical content of the present invention is described below through a specific implementation form, so that people familiar with this technology can easily understand the advantages and effects of the present invention from the content disclosed in this manual. However, the present invention can also be implemented or applied through other different specific implementation forms.

The present invention discloses a method for recovering metals from waste catalysts by using heating technology, as shown in the first figure. The process includes a step of performing a pulverization treatment of the waste catalyst to form a waste catalyst powder, a step of adding a strong acid to the waste catalyst powder to form a reaction solution, a step of placing the reaction solution in a high-pressure heating container for heating reaction, a step of performing liquid-slag separation, a step of performing a step of collecting a supernatant and a precipitated slag, and a step of precipitating different metals, so as to recover metals from the waste catalyst slag (blue mud, blue sludge〕to extract and recover metals such as nickel, cobalt, vanadium, etc., and the detailed description of the process steps is as follows; first, the step of performing a powdering treatment of the spent catalyst to form a spent catalyst powder is to dry, grind and screen the spent catalyst blue mud containing nickel and cobalt concentrate to form a spent catalyst powder, which mainly uses drying technology such as hot air drying, natural sun drying, etc. to dry the spent catalyst (blue mud), and then uses crushing and grinding machines such as jaw crusher, crusher, pulverizer, grinder, rotary mill or grinding mill The dried waste catalyst is ground into powder, and finally the powder is screened by a screening machine such as a vibrating sifter, a shaking sieve, or a standard sieve to obtain waste catalyst powder with a particle size in the range of ASTM sieve number #50~#200; secondly, the waste catalyst powder is added with a strong acid to form a reaction solution: an appropriate amount of waste catalyst powder is added to a 3~4.5 times sulfuric acid-based strong acid liquid. The present invention is best to add 3.8~4.2 times the strong acid liquid, and the strong acid liquid can be taken from a concentrated sulfuric acid solution _{[ H2SO4} 〕, which is to add the above-mentioned waste catalyst powder of a specific weight to the above-mentioned strong acid liquid with a specific weight ratio to form a reaction solution containing the waste catalyst; then, the above-mentioned reaction solution is placed in a high-pressure heating container for heating reaction: the above-mentioned reaction solution is placed in a high-pressure heating container, and the high-pressure heating container can be a high-pressure autoclave, and the high-pressure autoclave is placed in a silicone oil bath heating system The high pressure autoclave is heated and stirred in a silicone oil bath of a heating system, wherein the heating system can be selected from a silicone oil bath heating system, so that the waste catalyst powder in the reaction solution reacts with the strong acid liquid to form a resource solution to be precipitated, and the heating temperature is 150°C to 220°C, and the optimal heating temperature of the present invention is 180°C to 220°C, and the stirring reaction time is 15min to 15min. 0min, and the optimal stirring reaction time of the present invention is 60min~120min; then, the step of liquid-slag separation is performed: after the heating and stirring reaction, the solution to be precipitated is left to cool to room temperature of about 23°C, and the liquid phase and solid phase of the resource solution to be precipitated after the heating and stirring are separated, wherein the separation can be performed by a high-speed centrifuge or a filter to produce a liquid supernatant and a solid slag; The steps of collecting the supernatant and the precipitate are performed separately: after the resource solution to be precipitated is separated at a high speed, the supernatant and the precipitate are collected separately; and finally, the steps of precipitating different metals separately are performed: the supernatant is added with a precipitating agent of a corresponding concentration according to the metal to be precipitated, and the supernatant is separated and purified to recover the metal by using an existing precipitation technology, wherein the precipitation technology can be selected from an extraction precipitation method or a solvent precipitation method. For example, dialkylphosphonic acid (CYANEX272) with a concentration of at least 20% is added to the supernatant as an extractant, and the supernatant is extracted, separated, purified, and recovered to obtain nickel and cobalt. Sulfuric acid is then used for stripping, and the pH is adjusted to 3.0-5.0 to form a nickel sulfate solution. For the recovery of cobalt, sulfuric acid with a concentration of at least 4M is used to adjust the pH to 0-1 to form a cobalt sulfate solution.

The preferred embodiment of the present invention for recovering metal from waste catalyst by heating technology is to process waste catalyst blue mud containing nickel and cobalt concentrate into waste catalyst powder by drying, grinding and screening, and obtain 5 grams of waste catalyst powder with a particle size in the range of ASTM screening number #50~#200. Then, 5 grams of waste catalyst powder is added to 20 grams of 5N sulfuric acid concentrated solution of sulfuric acid system [5N _{H2SO4 ]} to form a reaction solution containing the above-mentioned waste catalyst. Then, the above-mentioned solution to be reacted is placed in an autoclave, and the autoclave is placed in a silicone oil bath heating system. The autoclave is heated and stirred in the silicone oil bath of the heating system to form a resource solution to be precipitated. In this embodiment, 160°C, 180°C and 220°C are used as the heating temperatures of the experiments, and 15min, 60min and 120min are used as the stirring reaction times of the three experiments. The reaction is then cooled to room temperature of about 23°C and then heated at high speed. The centrifuge separates the liquid phase and solid phase of the resource solution to be precipitated, and produces a liquid supernatant and a solid sludge. The supernatant and the sludge are then collected separately. The nickel metal extraction effect under different heating temperatures and reaction times is tested through experiments. The nickel metal concentration in the nickel sulfate solution obtained after the reaction will be analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for elements, and the recovery efficiency is calculated and compared to determine the optimal reaction conditions. After the supernatant is diluted 1000 times, the nickel metal concentration is analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). As shown in Figure 2, the experimental results show that when the stirring temperature is 180℃ and 200℃, the concentration of collectable nickel reaches 10,000ppm after only 15 minutes of stirring; while at 200℃, the nickel concentration after 15min and 60min of stirring has no obvious change. When the stirring time is 120min, the nickel concentration of the solution at different test temperatures of 160℃, 180℃ and 200℃ can reach 10,000ppm, and the nickel concentration of the sample at 200℃ even reaches more than 12,000ppm. The slag was stirred at 200℃ for 15min and 120min for elemental analysis. The two groups were subjected to repeated experiments. The experimental results showed that the nickel content of the slag was only 0.92%±0.01 and 0.53%±0.05, as shown in Table 1.

In this embodiment, the above two groups of samples were subjected to repeatability testing and analyzed by ICP-OES for various metals. In addition to nickel (Ni), aluminum (Al), cobalt (Co), iron (Fe), lithium (Li) and vanadium (V) were also measured to determine the content of precious metals, as shown in Table 2 and Table 3.

Table 2: Analysis of precious metal elements recovered after 15 minutes of reaction at 200℃

Finally, the supernatant is added with extractants of corresponding concentrations according to the metals to be extracted and precipitated, and the metals to be recovered are separated and purified by the existing extraction technology. For example, dialkylphosphonic acid [CYANEX272] with a concentration of at least 20% is added to the supernatant as an extractant, and the supernatant is extracted, separated and purified to recover nickel and cobalt, and sulfuric acid is used for stripping, and the pH is adjusted to 3.0-5.0 to form a nickel sulfate solution. For the recovery of cobalt, sulfuric acid with a concentration of at least 4M is used to adjust the pH to 0-1 to form a cobalt sulfate solution. According to the above experimental results, the nickel metal concentration precipitation rate reaches more than 90% under the conditions of reaction at a temperature of 200°C for 15min and 120min.

The present invention uses a heating technology to recover metals from waste catalysts. The waste catalysts are treated into waste catalyst powders, strong acid is added, and the waste catalysts are placed in a high-pressure heating container for oil bath heating reaction. The liquid and solid phases are then separated by high-speed centrifugation. After the supernatant of the liquid phase and the precipitate of the solid phase are collected separately, the metals are extracted and precipitated from the supernatant to achieve extraction from the waste catalyst slag containing nickel and cobalt concentrate. The purpose of recycling metals such as nickel and cobalt is to effectively shorten the extraction recovery time and increase the recovery rate to more than 90%. At the same time, it can effectively reduce the energy consumption during recycling to achieve the economic benefits of recycling, and then the waste catalyst can be resourced to solve the problem of existing stable landfill treatment, thereby overcoming the concern of environmental pollution.

The above embodiments are only preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any changes or embellishments made to the main design concept and spirit of the present invention that have no substantive significance and the technical problems they solve are still consistent with the present invention should be included in the scope of protection of the present invention.

From this, we can understand that this invention is a very creative creation. In addition to effectively solving the problems faced by practitioners, it also greatly improves the efficacy. In the same technical field, there is no same or similar product creation or public use. At the same time, it has improved efficacy. Therefore, this invention has met the requirements of invention patents regarding "novelty" and "progressiveness", and an invention patent application is filed in accordance with the law.

Claims (10)

A method for recovering metals from waste catalysts using heating technology, the process steps of which include: performing a powdering treatment on the waste catalyst to form a waste catalyst powder; adding the waste catalyst powder to a strong acid to form a solution to be reacted: taking a specific weight of the waste catalyst powder and adding it to a 3.5-4.5 times sulfuric acid-based strong acid liquid; placing the solution to be reacted in a high-pressure heating container for heating reaction: placing the solution to be reacted in a high-pressure heating container, and placing the high-pressure heating container in a heating system for heating and stirring to form a resource solution to be precipitated, wherein The heating temperature is 150℃~220℃, and the stirring reaction time is 15min~150min; one performs liquid-slag separation: the aforementioned resource solution to be precipitated is separated into liquid phase and solid phase to produce liquid supernatant and solid slag; one performs separate collection of supernatant and slag; and one precipitates different metals separately: the supernatant is added with precipitating agents of corresponding concentrations according to the metals to be precipitated, and the supernatant is separated and purified to recover the metals by typical precipitation technology; wherein the waste catalyst contains nickel-cobalt concentrate, and the precipitating agent contains dialkylphosphonic acid with a concentration of at least 20%. The method for recovering metals from waste catalysts using heating technology as described in claim 1 is characterized in that the waste catalyst powder in the step of adding a strong acid to form a reaction solution is formed by drying, grinding and sieving, and the particle size of the waste catalyst powder meets the range of ASTM sieve number #50~#200. The method for recovering metals from waste catalysts using heating technology as described in claim 1 is characterized in that the weight ratio of the waste catalyst powder to the strong acid liquid in the step of adding the waste catalyst powder to a strong acid to form a reaction solution is 1:3.8~4.2. The method for recovering metals from waste catalysts using heating technology as described in claim 1 or 3 is characterized in that the strong acid liquid can be obtained from concentrated sulfuric acid (H ₂ SO ₄ ). The method for recovering metals from waste catalysts using heating technology as described in claim 1 is characterized in that the high-pressure heating container in the step of placing the aforementioned solution to be reacted in a high-pressure heating container for heating reaction can be a high-pressure autoclave. The method for recovering metals from waste catalysts using heating technology as described in claim 1 is characterized in that the heating temperature in the step of placing the aforementioned solution to be reacted in a high-pressure heating container for heating reaction is 180°C to 220°C, and the stirring reaction time is 60min to 120min. The method for recovering metals from waste catalysts using heating technology as described in claim 1, 5 or 6 is characterized in that: in the step of placing the aforementioned solution to be reacted in a high-pressure heating container for heating reaction, the high-pressure heating container is placed in a heating system using a silicone oil bath for heating and stirring. The method for recovering metal from waste catalyst using heating technology as described in claim 1 is characterized in that: the liquid-slag separation step uses high-speed centrifugation to separate the liquid-slag. The method of recovering metals from waste catalysts by using heating technology as described in claim 1 is characterized in that: in the step of separating different metals, the supernatant is added with extractants of corresponding concentrations according to the metals to be extracted and separated, and the supernatant is separated and purified by extraction technology to recover the metals. The method for recovering metals from waste catalysts using heating technology as described in claim 9 is characterized in that: in the step of separating different metals, dialkylphosphonic acid (CYANEX272) with a concentration of at least 20% can be added to the supernatant as an extractant, and the supernatant is extracted, separated, purified, and recovered to obtain nickel and cobalt, and sulfuric acid is used for stripping to adjust the pH to 3.0-5.0 to form a nickel sulfate solution. For the recovery of cobalt, sulfuric acid with a concentration of at least 4M is used to adjust the pH to 0-1 to form a cobalt sulfate solution.