A method for resource utilization of waste hydrogenation catalyst

Abstract

The application discloses a kind of resource utilization methods of waste hydrogenation catalyst.The method comprises the following steps: (1) waste hydrogenation catalyst pretreatment;(2) the material obtained in step (1) is treated by alkali leaching, solid-liquid separation, to obtain leaching solution and leaching residue;(3) the leaching solution obtained in step (2) is added Mo precipitant, after solid-liquid separation, the obtained solid is ammonium molybdophosphate product, the obtained liquid is used;(4) the liquid obtained in step (3) is added Co precipitant, after solid-liquid separation, the obtained solid is calcined to obtain Co oxide product.The method provided by the application not only greatly inhibits the leaching problem of Al, reduces the separation cost of subsequent Al, but also can obtain high-purity Mo and Co products, and the remaining residue can be used to prepare alumina, realizing full-element high-value utilization.The method provided by the application is simple in process, easy to operate, low in cost, and can be used in the production of waste hydrogenation catalyst recovery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste catalyst recovery, and more particularly to a resource utilization method of waste hydrogenation catalyst. BACKGROUND

[0002] Hydrogenation catalysts play an important role in the oil refining industry. With the increasingly stringent requirements for environmental protection, one of the main development directions of future oil refining is to improve the ability to produce clean fuels, and hydrogenation technology is the main measure to achieve clean oil. Hydrogenation catalysts are generally composed of carrier active alumina and metal active components. The annual demand for hydrogenation catalysts is about 150-170 thousand tons, and the service life is mostly 1-4 years. Therefore, a large amount of waste hydrogenation catalysts are generated every year. According to the National Hazardous Waste Directory (2021 edition), such waste catalysts and incineration residues are classified as hazardous waste, and the transportation and treatment methods are limited.

[0003] The common recovery methods of various waste industrial catalysts are generally divided into dry method, wet method and dry-wet combined method. At present, the dry method recovery has been relatively mature because of its simple operation and no need for too much engineering experience, but it cannot separate similar metals, and the dry method also has the disadvantages of high energy consumption and serious pollution. The wet method recovery is more suitable for processing complex secondary resources such as waste catalysts, the material transportation pipeline is closed, and no toxic and harmful gases are generated, but the wet method recovery process is long, and most of the researches are still at the laboratory stage. At present, a complete industrialized technology has not been formed at home and abroad.

[0004] The waste alumina carrier hydrogenation catalyst contains metals such as molybdenum, vanadium, cobalt and nickel, which has high economic value. At present, most of the recovery technologies mainly focus on the recovery of metals. For example, CN202011594898.1 discloses a method for recovering molybdenum from waste hydrogenation catalyst, which mixes and grinds the waste hydrogenation catalyst with red mud, then roasts and immerses in water, and after the alumina hydroxide in the leaching solution is precipitated, the molybdenum-containing acidic solution is selectively extracted with a chelating extractant. After reverse extraction, evaporation and crystallization, ammonium molybdate products are obtained. CN202010520557.3 discloses a process for recycling waste cobalt-molybdenum hydrogenation catalyst, which obtains an acid leaching solution by acid leaching treatment, directly extracts the acid leaching solution to obtain a Mo-containing extraction solution, and then performs reverse extraction, precipitation and pyrolysis to obtain a Mo-containing product. The Al-containing extraction solution is subjected to reverse extraction and subsequent treatment to obtain an Al-containing product. CN202110728404.2 discloses a method for extracting vanadium, nickel and molybdenum from waste catalyst by ammonium sulfate solution leaching, which realizes efficient leaching of vanadium, nickel and molybdenum in waste catalyst, and obtains vanadium, nickel and molybdenum-containing ammonium sulfate leaching solution and aluminum-containing tailings.

[0005] Currently, the wet treatment of waste hydrogenation catalyst mainly uses acid leaching method. A large amount of Al element is dissolved in the acid leaching process, thereby causing difficulty in subsequent separation of Al and increasing separation cost. In addition, existing literatures use alkali leaching method, for example, CN201310499213.9 and CN201610003157.9 both use alkali to treat waste catalyst, but the problem of being unable to inhibit Al leaching still exists. Therefore, it is crucial to provide a new resource utilization method of waste hydrogenation catalyst. SUMMARY

[0006] In order to solve the problem of a large amount of Al element being dissolved in the acid / alkali leaching process in the prior art, thereby causing difficulty in subsequent separation of Al and increasing separation cost, the present application provides a resource utilization method of waste hydrogenation catalyst. The method not only greatly inhibits the problem of Al leaching and reduces the separation cost of subsequent Al, but also can obtain high-purity Mo and Co products, and the remaining residue can be used to prepare alumina, realizing full-element high-value utilization. The method provided by the present application is simple in process, easy to operate, low in cost, and can be used in the production of waste hydrogenation catalyst recovery.

[0007] The first aspect of the present application provides a resource utilization method of waste hydrogenation catalyst, comprising the following steps:

[0008] (1) pretreatment of waste hydrogenation catalyst;

[0009] (2) alkali leaching treatment of the material obtained in step (1), solid-liquid separation, to obtain leaching liquid and leaching residue;

[0010] (3) adding Mo precipitant to the leaching liquid obtained in step (2), and after solid-liquid separation, the obtained solid is ammonium molybdophosphate product, and the obtained liquid is reserved;

[0011] (4) adding Co precipitant to the liquid obtained in step (3), and after solid-liquid separation, the obtained solid is calcined to obtain Co oxide product.

[0012] In the above technical solution, the waste hydrogenation catalyst in step (1) comes from a pyrolysis gasoline hydrogenation device, and the hydrogenation catalyst includes alumina, molybdenum oxide, cobalt oxide and phosphorus oxide. Before use, the hydrogenation catalyst needs to be converted from the oxidized state to the sulfided state, i.e. the hydrogenation active metals molybdenum and cobalt are converted into sulfides.

[0013] In the above technical solution, the pretreatment method in step (1) is calcination at 400℃-700℃ for 4h-12h. The waste catalyst that has been heat treated before disassembly does not need to be pretreated.

[0014] In the above technical solution, the purpose of the pretreatment in step (1) is mainly to remove the surface organic matter in the spent hydrogenation catalyst, and the organic matter includes C5 and above hydrocarbons.

[0015] In the above technical solution, the alkali leaching agent used in the alkali leaching process in step (2) is a composite leaching agent, which includes a basic solvent and an additive, wherein the basic solvent is selected from ammonia water, and the additive is selected from at least one of ammonium carbonate, ammonium bicarbonate, sodium carbonate and sodium bicarbonate; preferably, in the composite leaching agent, the concentration of the basic solvent is 0.5-10 mol / L, preferably 1-8 mol / L; and the concentration of the additive is 0.5-6 mol / L.

[0016] Further, the molar ratio of nitrogen to carbon in the composite leaching agent in step (2) is 2.25:1-12:1, preferably 4.5:1-12:1, and as a non-limiting example, it can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, etc.

[0017] Further, the reaction temperature in the alkali leaching process is 40-180℃, and the reaction time is 1-72h. Preferably, the reaction temperature in the alkali leaching process is 80-180℃, and the reaction time is 1-8h.

[0018] In the above technical solution, the leaching rate of Co in the leaching solution in step (2) is more than 20%, the leaching rate of Mo is more than 80%, and the leaching rate of Al is less than 1%.

[0019] In the above technical solution, the leaching residue generated in step (2) can be used to prepare alumina.

[0020] In the above technical solution, in step (3), the Mo precipitating agent is an inorganic acid, preferably selected from at least one of nitric acid, sulfuric acid and hydrochloric acid, and the obtained precipitate is an ammonium molybdophosphate product, which is easy to be suction filtered.

[0021] In the above technical solution, in the precipitation process of step (3), the pH is adjusted to 0.1-6, preferably 0.3-0.5; the precipitation time is 1-48h, preferably 4-24h; and the precipitation temperature is 25-105℃, preferably 45-65℃.

[0022] In the above technical solution, in step (3), the precipitation rate of Mo is more than 90%, and the obtained precipitate is an ammonium molybdophosphate product.

[0023] In the above technical solution, NH3 and CO2 generated in the Mo precipitation process are recycled and returned to step (2) for reuse.

[0024] In the technical solution, in step (4), the Co precipitant is a heavy metal capturing agent, preferably at least one selected from DTCs and xanthates, and specifically at least one selected from potassium ethyl xanthate, potassium amyl xanthate and dithiocarbamate; preferably, the molar ratio of the Co precipitant to Co in the liquid obtained in step (3) is 2:1-5:1, preferably 2:1-3:1.

[0025] In the technical solution, in step (4), the calcination condition is 600-1000 DEG C for 3-10 h.

[0026] In the technical solution, in step (4), the precipitation rate of Co is greater than 90%, and the oxide of Co is obtained.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] The method for resource utilization of waste hydrogenation catalyst provided by the present application can effectively recover waste hydrogenation catalyst that cannot be regenerated after industrial operation, and is an environmentally friendly recycling method. The method uses a specific concentration and molar ratio of carbonate / hydrogen carbonate and ammonium ion complex to effectively inhibit the leaching of Al and reduce the subsequent separation cost of Al, and adds Mo and Co precipitants respectively to obtain high-purity Mo and Co products, and the remaining slag can be used to prepare alumina, realizing full-element high-value utilization. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 XRD pattern of the Mo-containing product in Example 1;

[0030] Figure 2 SEM pattern of the Mo-containing product in Example 1. DETAILED DESCRIPTION

[0031] The following examples will further illustrate the method for synthesizing molecular sieves provided by the present application, but the scope of protection of the present application is not limited by the examples.

[0032] In the present application, the scanning electron microscope (SEM) photos of the samples are taken on a Hitachi S-4800II scanning electron microscope.

[0033] In the present application, the test conditions of XRD: molecular sieve crystal phase analysis is performed by using a Japan Rigaku-Ultima X-ray diffractometer. CuKα radiation, wavelength λ=0.15432 nm. The scanning range of the X-ray diffraction pattern is 2θ 5-50°, and the scanning speed is 10° / min.

[0034] In the present application, the leaching rate is defined as the mass of metal in the filtrate divided by the total mass of metal in the raw material, and the leaching rate of each metal is calculated according to the ICP result. The specific method is as follows: the reaction product is suction filtered, the concentration of Co, Mo and Al in the filtrate is measured by an inductively coupled plasma emission spectrometer (ICP, Varian, 725-ES), and then calculation is performed to obtain the result.

[0035] Example 1

[0036] (1) A waste Co-Mo / Al2O3 catalyst raw material is put into a muffle furnace and burned at 550°C for 4h (wherein, in mass percentage, Al2O3 is 82.17%, MoO3 is 11.17%, CoO is 3.01%, P2O5 is 2.96%, and the rest is other).

[0037] (2) 800g of the material obtained in step (1) is put into an autoclave, 8L of ammonia water and ammonium carbonate solution are poured in, wherein the concentration of ammonia water and ammonium carbonate is 0.5mol / L and 2mol / L respectively, and the molar ratio of N and C is 2.25:1. Stirring is started, the leaching temperature is 90°C, and the reaction time is 1h. The reaction product is suction filtered, and the concentration of Co, Mo and Al in the filtrate is measured by an inductively coupled plasma emission spectrometer (ICP, Varian, 725-ES). The leaching rate is defined as the mass of metal in the filtrate divided by the total mass of metal in the raw material, and the leaching rate of Co is calculated to be 20%, the leaching rate of Mo is calculated to be 90%, and the leaching rate of Al is calculated to be 0% according to the ICP result.

[0038] (3) The leaching solution obtained in step (2) is precipitated with concentrated nitric acid, and the test is performed under the conditions of pH 0.3, precipitation time 4h, and precipitation temperature 65°C. The precipitation rate of Mo is 99.3%, and the obtained precipitate is ammonium molybdate product. The leaching residue obtained in step (2) is put into a muffle furnace and calcined at 550°C for 4h to obtain γ-Al2O3 with a specific surface area of 213.6m2 / g, which is comparable to commercial alumina. The catalyst prepared with this γ-Al2O3 is used for naphthalene selective hydrogenation reaction, and the effect is comparable to that reported in the literature. 2

[0039] (4) The filtrate obtained in step (3) is added with potassium ethyl xanthate at a molar ratio of Co:Co precipitant of 1:2, and the precipitation rate of Co is 99.6%. After calcination at 800°C for 4h, the oxide of Co is obtained.

[0040] Example 2

[0041] ​According to the method of Example 1, except that the concentration of ammonia and ammonium carbonate in step (2) is 8 mol / L and 2 mol / L respectively, and the molar ratio of N and C is 6:1, the leaching rate of Co is 51%, the leaching rate of Mo is 89%, and the leaching rate of Al is 0% according to the ICP results.

[0042] Example 3

[0043] According to the method of Example 1, except that the concentration of ammonia and ammonium carbonate in step (2) is 10 mol / L and 1 mol / L respectively, and the molar ratio of N and C is 12:1, the leaching rate of Co is 53%, the leaching rate of Mo is 92%, and the leaching rate of Al is 0% according to the ICP results.

[0044] Example 4

[0045] According to the method of Example 1, except that the concentration of ammonia and ammonium bicarbonate in step (2) is 5 mol / L and 4 mol / L respectively, and the molar ratio of N and C is 2.25:1, the leaching rate of Co is 52%, the leaching rate of Mo is 82%, and the leaching rate of Al is 0% according to the ICP results.

[0046] Example 5

[0047] According to the method of Example 1, except that the concentration of ammonia and sodium carbonate in step (2) is 8 mol / L and 2 mol / L respectively, and the molar ratio of N and C is 4:1, the leaching rate of Co is 53%, the leaching rate of Mo is 85%, and the leaching rate of Al is 0% according to the ICP results.

[0048] Example 6

[0049] According to the method of Example 1, except that concentrated hydrochloric acid is added for precipitation in step (3), and the test is carried out under the conditions of pH 0.5, precipitation time 24 h, and precipitation temperature 45℃, the precipitation rate of Mo is 98.4%.

[0050] Example 7

[0051] According to the method of Example 1, except that potassium ethyl xanthate is added in step (4) with a molar ratio of Co to precipitant of 1:5, the precipitation rate of Co is 99.5%, and the oxide of Co is obtained after the precipitation is calcined.

[0052] Example 8

[0053] According to the method of Example 1, except that potassium pentyl xanthate is added in step (4) with a molar ratio of Co to precipitant of 1:4, the precipitation rate of Co is 99.4%, and the oxide of Co is obtained after the precipitation is calcined.

[0054] Example 9

[0055] According to the method described in Example 1, the difference is that in step (4), dithiocarbamate is added at a molar ratio of Co: precipitant of 1:2, the precipitation rate of Co is 99.6%, and the oxide of Co is obtained after calcination of the precipitate.

[0056] Comparative Example 1

[0057] According to the method described in Example 1, the difference is that in step (2), only 0.5 mol / L ammonia water is used as the leaching agent and ammonium carbonate is not added. According to the ICP results, the leaching rate of Co is 8%, the leaching rate of Mo is 68%, and the leaching rate of Al is 17%, which requires increasing the cost of subsequent Al separation.

[0058] Comparative Example 2

[0059] According to the method described in Example 1, the difference is that in step (2), only 2 mol / L ammonium carbonate is used as the leaching agent and no ammonia is added. According to the ICP results, the leaching rate of Co is 15%, the leaching rate of Mo is 80%, and the leaching rate of Al is 3%.

Claims

1. A method for the resource utilization of waste hydrogenation catalyst, comprising the following steps: (1) Pretreatment of waste hydrogenation catalyst; (2) The material obtained in step (1) is subjected to alkaline leaching treatment and solid-liquid separation to obtain leachate and leachate residue; (3) Mo precipitant was added to the leachate obtained in step (2). After solid-liquid separation, the solid obtained was ammonium phosphomolybdate product, and the liquid obtained was left for use. (4) The liquid obtained in step (3) is added with Co precipitant, and after solid-liquid separation, the resulting solid is calcined to obtain Co oxide product; The alkaline leaching process in step (2) uses an alkaline leaching agent, which is a composite leaching agent, including an alkaline solvent and an additive. The alkaline solvent is selected from ammonia water, and the additive is selected from at least one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate. The molar ratio of nitrogen to carbon in the composite leaching agent is 2.25:1 to 12:

1.

2. The method according to claim 1, characterized in that, The waste hydrogenation catalyst mentioned in step (1) comes from a cracked gasoline hydrogenation unit, and the hydrogenation catalyst includes alumina, molybdenum oxide, cobalt oxide and phosphorus oxide.

3. The method according to claim 1, characterized in that, The pretreatment method described in step (1) is to calcine at 400℃~700℃ for 4 h~12 h.

4. The method according to claim 1, characterized in that, The leaching rate of Co in the leachate in step (2) is more than 20%, the leaching rate of Mo is greater than 80%, and the leaching rate of Al is less than 1%.

5. The method according to claim 1, characterized in that, In step (3), the Mo precipitant is an inorganic acid.

6. The method according to claim 5, characterized in that, In step (3), the Mo precipitant is selected from at least one of nitric acid, sulfuric acid, and hydrochloric acid.

7. The method according to claim 1, characterized in that, During the precipitation process in step (3), the pH is adjusted to 0.1~6, the precipitation time is 1~48 h, and the precipitation temperature is 25~105℃.

8. The method according to claim 1, characterized in that, In step (4), the Co precipitant is a heavy metal scavenger.

9. The method according to claim 8, characterized in that, In step (4), the Co precipitant is selected from at least one of potassium ethyl xanthate, potassium pentyl xanthate, and dithiocarbamate.

10. The method according to claim 1, characterized in that, In step (4), the molar ratio of Co in the Co precipitant and the liquid obtained in step (3) is 2:1 to 5:1.

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