A process for recovering vanadium and molybdenum from spent petrochemical catalysts

Abstract

The application belongs to the technical field of solid waste resource recycling and treatment in petrochemical industry, and particularly discloses a method for recovering vanadium and molybdenum from waste petrochemical catalysts. The method directly mixes granular waste petrochemical catalysts with an activating agent, and then performs short-time calcination in a microwave environment to obtain calcined slag. The calcined slag is directly treated by a low-speed stirring water immersion process, and after solid-liquid separation, leaching liquor containing rare metals vanadium and molybdenum and leaching slag which can be directly used as a catalyst carrier raw material are obtained. The method can realize rapid recovery of rare metals such as vanadium and molybdenum in waste petrochemical catalysts, has short recovery and treatment time, high recovery rate, and the waste catalysts after recovery and treatment have high alumina content and can be directly used as catalyst carrier raw materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid waste resource recycling and treatment in petrochemical industry, in particular to a method for recovering vanadium and molybdenum from waste petrochemical catalysts. BACKGROUND

[0002] With the rapid development of modern chemical industry at home and abroad, the demand for vanadium, molybdenum and other raw materials is increasing year by year. Relying solely on the extraction of vanadium, molybdenum and their compounds from ores cannot meet the needs of production development, so the recycling and reuse of secondary resources containing vanadium and molybdenum have important strategic significance.

[0003] Waste petrochemical catalyst is an important secondary resource, which is rich in vanadium, molybdenum and other rare metals, and some even far exceed the content of corresponding components in some poor ores, but it also contains harmful elements such as S and C, and is a dangerous solid secondary resource with important economic value. Due to the complexity of the composition of waste petrochemical catalyst, it is difficult to treat, so it is of great environmental and economic benefit to carry out comprehensive recycling and utilization research of waste petrochemical catalyst.

[0004] Currently, there are two methods for recycling and treating waste catalysts: fire treatment and wet treatment. The fire treatment generally involves high-temperature roasting first, followed by leaching. The traditional fire treatment process has problems such as high energy consumption, long time consumption and environmental pollution, which gradually cannot meet the current environmental protection requirements. Wet treatment methods include atmospheric acid leaching and atmospheric alkali leaching. The main problems of the wet treatment process are poor adaptability of raw materials, metal dispersion and low production efficiency. The existing treatment of waste petrochemical catalysts generally refers to the traditional fire process or wet process, and it is found in the actual treatment process that there are problems such as low resource recovery rate, high energy consumption, and the aluminum-based carrier is also easily leached out, which increases the difficulty of separation of vanadium and molybdenum and is not conducive to the reuse of the catalyst carrier. SUMMARY

[0005] The technical problem solved by the present application is to provide a method for recovering vanadium and molybdenum from waste petrochemical catalysts, which can realize the rapid recovery of vanadium, molybdenum and other rare metals in waste petrochemical catalysts, has short recovery and treatment time, high recovery rate, and the recovered waste catalyst can be directly used as a catalyst carrier raw material.

[0006] The technical solution adopted by the present application is: the present application provides a method for recovering vanadium and molybdenum from waste petrochemical catalysts, comprising the following steps:

[0007] Mixing the waste petrochemical catalyst with an activating agent, then short-time roasting in a microwave environment to obtain roasting slag;

[0008] Treating the roasting slag by low-speed stirring water leaching process, then solid-liquid separation to obtain leaching solution containing rare metals vanadium and molybdenum and leaching residue.

[0009] As an embodiment of the present application, the waste petrochemical catalyst is a waste catalyst with alumina as a carrier, preferably after being deoiled and mixed with an activating agent. The granular waste petrochemical catalyst after being deoiled is directly mixed with the activating agent and then subjected to subsequent treatment, without the need of grinding the waste petrochemical catalyst and then mixing with the activating agent.

[0010] As an embodiment of the present application, the activating agent is sodium chloride and / or sodium sulfate. For example, the activating agent can be sodium chloride, sodium sulfate or a mixture of sodium chloride and sodium sulfate.

[0011] Further preferably, the activating agent is mixed with the waste petrochemical catalyst after being made into a thick paste by adding water.

[0012] As an embodiment of the present application, the amount of the activating agent is 1-3 times, preferably 1-2.5 times of the total moles of vanadium and molybdenum in the waste petrochemical catalyst.

[0013] As an embodiment of the present application, the waste petrochemical catalyst mixed with the activating agent is first subjected to short-time drying and then short-time calcination; the short-time drying is controlled for 5-12 min and at a temperature of 80-110°C.

[0014] Preferably, the short-time drying is controlled for 10 min and at a temperature of 100°C.

[0015] As an embodiment of the present application, the microwave conditions for the short-time calcination are: microwave power of 1000-1500 W and time control of 8-10 min. The calcination temperature for the short-time calcination is 600-700°C.

[0016] As an embodiment of the present application, the low-speed stirring water immersion process for treating the calcination residue includes: preparing a water immersion material by adding water to the calcination residue, and then controlling the temperature for stirring reaction. Preferably, the temperature is controlled at 60-75°C.

[0017] Preferably, the solid-liquid ratio of the water immersion material is 0.20-0.40 g / mL.

[0018] As an embodiment of the present application, the stirring speed is controlled at 100-200 rpm.

[0019] As an embodiment of the present application, the water immersion treatment time is 10-20 min.

[0020] As an embodiment of the present application, the leaching residue obtained by the present application has an alumina content of ≥98% by mass, with high purity, and can be used for preparing petrochemical catalysts and directly used as a carrier raw material for preparing new petrochemical catalysts.

[0021] The raw material waste petrochemical catalyst treated in the application is a waste catalyst with alumina as a carrier after deoiling treatment, which has a unique structure, wherein vanadium and molybdenum mainly exist in the form of oxides and sulfides and are adsorbed on the surface of the alumina carrier. The effective separation of rare metals from the carrier alumina is a common difficult problem, because alumina is amphoteric, and the traditional process generally uses acid or alkaline medium to recover rare metals, so the dissolution of aluminum cannot be avoided, and the treatment causes aluminum to be dispersed in the leaching residue and leaching liquid, which is not conducive to subsequent recycling.

[0022] The inventors found that the oxides and sulfides of vanadium and molybdenum in the waste petrochemical catalyst are strong microwave absorbing substances, and the carrier alumina is a weak microwave absorbing substance. Based on the difference in microwave performance and the special structure of the waste catalyst, the recovery treatment scheme of the application is proposed. In the microwave short-time roasting process, the microwave has the characteristic of selective heating of specific substances. The vanadium and molybdenum on the surface of the carrier alumina are rapidly heated to the reaction temperature with the activator, realizing the soluble conversion of the vanadium and molybdenum phase, while the carrier alumina has poor wave absorption ability and slow heating speed, and basically does not react with the activator, thus realizing the rapid and efficient dissolution of the rare metals vanadium and molybdenum and the effective separation from the carrier metal alumina. The leaching liquid treated by the application has high vanadium and molybdenum content and very low aluminum content; aluminum mainly exists in the leaching residue, and the mass percentage of alumina in the leaching residue is ≥98%, with high purity, which can be directly used as a carrier raw material for preparing new petrochemical catalysts.

[0023] It is also found in the research that if the microwave roasting time is too long, the alumina can also reach the reaction temperature with the activator due to the effect of heat transfer, so it is very important to control the roasting time. By controlling the microwave roasting time within a suitable time, the effective conversion of vanadium and molybdenum and the inhibition of the reaction of alumina can be realized.

[0024] The application directly microwave short-time roasts the granular waste catalyst, discards the grinding process required by the traditional process, and significantly reduces the energy consumption of the process. When the activator is mixed with the cylindrical granular waste petrochemical catalyst, in order to ensure that the activator can uniformly cover the surface of the cylindrical particles, the activator is mixed with the cylindrical granular waste catalyst after being mixed with water to form a viscous state, and then short-time heating and drying are performed, realizing uniform mixing.

[0025] The roasting slag obtained by the microwave roasting treatment is treated by low-speed stirring water immersion process without destroying the overall particle size and structure of the carrier metal therein, that is, the stirring speed and stirring time of the immersion process are strictly controlled. If the stirring speed is too fast or the stirring time is too long, the particles are easily crushed, which is not conducive to the direct recycling and reuse of the carrier metal. Since the microwave short-time roasting realizes the efficient soluble conversion of vanadium, molybdenum and other rare metals, the soluble substances directly adhere to the surface of the cylindrical particle catalyst, and the short-time low-speed stirring immersion process can ensure the high leaching rate of vanadium and molybdenum and the reusability of the carrier metal, and the leaching solution containing vanadium and molybdenum and the high-purity cylindrical catalyst carrier which can be directly reused are obtained.

[0026] The method for recovering vanadium and molybdenum from waste petrochemical catalyst provided by the application directly mixes the granular waste catalyst with an activator, then performs short-time roasting in a microwave environment to obtain roasting slag, and then directly uses a low-speed stirring water immersion process to treat the roasting slag to obtain a leaching solution and a leaching residue. Experiments show that most of the vanadium and molybdenum in the waste petrochemical catalyst can be leached by using the method, the recovery rates of vanadium and molybdenum can reach 95-98% and 96-98% respectively, the leaching rate of the carrier metal aluminum is less than 0.5%, the purity of the obtained leaching solution is high, and the subsequent purification process of vanadium and molybdenum is greatly simplified. The leaching residue after leaching contains ≥98% of aluminum oxide, has high purity, and can be directly used as a raw material for preparing a new petrochemical catalyst carrier.

[0027] The method for recovering vanadium and molybdenum from waste petrochemical catalyst provided by the application realizes the rapid recovery of vanadium and molybdenum in the waste catalyst and the effective separation from the carrier metal, and the recovery treatment method has low production cost, low labor intensity and short processing time, improves the processing amount of the waste catalyst, is more conducive to promoting the resource treatment of the waste catalyst, and realizes energy saving, emission reduction and green production in the vanadium and molybdenum industry. DETAILED DESCRIPTION

[0028] The technical solutions of the application will be described in detail below through specific examples.

[0029] In the following examples or comparative examples, the reagents used are all commercially available. The percentages in each example are mass percentages.

[0030] Example 1

[0031] The raw material waste petrochemical catalyst treated in this example is a waste aluminum-based catalyst provided by a domestic petrochemical enterprise after oil removal treatment, which has a cylindrical solid particle shape, and its main valuable metal chemical composition analysis is shown in the following table, wherein the content of each element is the mass percentage content.

[0032]

[0033] The method for recovering vanadium and molybdenum in the embodiment comprises the following steps:

[0034] S1: The activating agent sodium sulfate (the amount is 1.2 times of the total moles of vanadium and molybdenum in the waste petrochemical catalyst) is mixed with water to form a thick slurry, and then the granular waste petrochemical catalyst is directly added and uniformly stirred and mixed;

[0035] Then, it is placed in an oven for short-time drying, the drying time is 10 min, and the drying temperature is 100℃;

[0036] After drying, it is placed in a microwave roasting device for short-time roasting, and the microwave conditions are controlled as follows: microwave power is 1500W, roasting temperature is 600℃, and roasting time is 8 min, to obtain roasted slag;

[0037] S2: The roasted slag obtained in step S1 is slurried with water to obtain water immersion material with a solid-liquid ratio of 0.30 g / mL, and then temperature-controlled stirring reaction is performed, the stirring speed is 150 rpm, the water immersion temperature is 70℃, and the stirring time is 15 min;

[0038] After water immersion treatment, solid-liquid separation is performed to obtain leaching solution containing rare metals vanadium and molybdenum and leaching residue.

[0039] Analysis shows that most of the vanadium and molybdenum in the waste petrochemical catalyst enter the leaching solution, the vanadium recovery rate is 98%, the molybdenum recovery rate is 97%, and the aluminum leaching rate is 0.4%. The aluminum oxide content in the leaching residue is 98.5%.

[0040] In the leaching solution, the mass fraction of vanadium is 57.64% and the mass fraction of molybdenum is 41.84% according to the total mass of metals, the leaching solution mainly contains vanadium and molybdenum, and the purity is high.

[0041] Example 2

[0042] The raw material waste petrochemical catalyst treated in the embodiment is the same as that in embodiment 1.

[0043] The method for recovering vanadium and molybdenum in the embodiment comprises the following steps:

[0044] S1: The activating agent sodium sulfate (the amount is 1.2 times of the total moles of vanadium and molybdenum in the waste petrochemical catalyst) is mixed with water to form a thick slurry, and then the granular waste petrochemical catalyst is directly added and uniformly stirred and mixed;

[0045] Then, it is placed in an oven for short-time drying, the drying time is 10 min, and the drying temperature is 100℃;

[0046] After drying, the waste petrochemical catalyst is placed in a microwave calcination device for short-time calcination, and the microwave conditions are controlled as follows: microwave power 1000 W, calcination temperature 700 DEG C, and calcination time 9 min, to obtain calcination residue;

[0047] S2: The calcination residue obtained in step S1 is mixed with water to obtain water immersion material with a solid-liquid ratio of 0.20 g / mL, and then temperature-controlled stirring reaction is carried out, with a stirring speed of 200 rpm, a water immersion temperature of 60 DEG C, and a stirring time of 20 min.

[0048] After the water immersion treatment, solid-liquid separation is performed to obtain leaching solution containing rare metals vanadium and molybdenum and leaching residue.

[0049] Analysis shows that most of the vanadium and molybdenum in the waste petrochemical catalyst enter the leaching solution, the vanadium recovery rate is 97%, the molybdenum recovery rate is 96%, and the aluminum leaching rate is 0.2%. The aluminum oxide content in the leaching residue is 98%.

[0050] In the leaching solution, the mass fraction of vanadium is 57.79% and the mass fraction of molybdenum is 41.95% according to the total mass of metals, and the leaching solution mainly contains vanadium and molybdenum with high purity.

[0051] Example 3

[0052] The raw material waste petrochemical catalyst treated in this embodiment is the same as that in Embodiment 1.

[0053] The method for treating and recovering vanadium and molybdenum in this embodiment specifically includes the following steps:

[0054] S1: A mixture of activating agents sodium chloride and sodium sulfate (the amount is 2 times the total molar number of vanadium and molybdenum in the waste petrochemical catalyst) is mixed with water to form a thick slurry, and then the granular waste petrochemical catalyst is directly added and uniformly stirred and mixed;

[0055] Then, the mixture is placed in an oven for short-time drying, with a drying time of 10 min and a drying temperature of 100 DEG C.

[0056] After drying, the waste petrochemical catalyst is placed in a microwave calcination device for short-time calcination, and the microwave conditions are controlled as follows: microwave power 1000 W, calcination temperature 700 DEG C, and calcination time 9 min, to obtain calcination residue;

[0057] S2: The calcination residue obtained in step S1 is mixed with water to obtain water immersion material with a solid-liquid ratio of 0.20 g / mL, and then temperature-controlled stirring reaction is carried out, with a stirring speed of 200 rpm, a water immersion temperature of 60 DEG C, and a stirring time of 20 min.

[0058] After the water immersion treatment, solid-liquid separation is performed to obtain leaching solution containing rare metals vanadium and molybdenum and leaching residue.

[0059] The analysis shows that most of the vanadium and molybdenum in the waste petrochemical catalyst enter the leaching solution, the vanadium recovery rate is 97%, the molybdenum recovery rate is 96%, and the aluminum leaching rate is 0.3%. The aluminum oxide content in the leaching residue is 99%.

[0060] The mass fraction of vanadium in the leaching solution is 57.71% and the mass fraction of molybdenum is 41.89% according to the total mass of metals, the leaching solution mainly contains vanadium and molybdenum, and the purity is high.

[0061] Example 4

[0062] The raw material waste petrochemical catalyst treated in this embodiment is the same as that in Embodiment 1.

[0063] The method for recovering vanadium and molybdenum in this embodiment specifically comprises the following steps:

[0064] S1: Mix the mixture of activating agents sodium chloride and sodium sulfate (the amount is 2.5 times the total moles of vanadium and molybdenum in the waste petrochemical catalyst) with water to form a thick slurry, then directly add the granular waste petrochemical catalyst and stir to mix uniformly;

[0065] Then put it into an oven for short-time drying, the drying time is 10 min and the drying temperature is 100℃;

[0066] After drying, put it into a microwave roasting device for short-time roasting, the microwave conditions are controlled as follows: microwave power 1500W, roasting temperature 600℃, roasting time 10 min, to obtain roasted slag;

[0067] S2: Slurry the roasted slag obtained in step S1 with water to obtain water immersion material with a solid-liquid ratio of 0.30 g / mL, then control the temperature and stir to react, the stirring speed is 100 rpm, the water immersion temperature is 75℃, and the stirring time is 15 min;

[0068] After water immersion treatment, solid-liquid separation is performed to obtain leaching solution containing rare metals vanadium and molybdenum and leaching residue.

[0069] The analysis shows that most of the vanadium and molybdenum in the waste petrochemical catalyst enter the leaching solution, the vanadium recovery rate is 95%, the molybdenum recovery rate is 98%, and the aluminum leaching rate is 0.2%. The aluminum oxide content in the leaching residue is 98.5%.

[0070] The mass fraction of vanadium in the leaching solution is 56.78% and the mass fraction of molybdenum is 42.96% according to the total mass of metals, the leaching solution mainly contains vanadium and molybdenum, and the purity is high.

[0071] From the above examples, it can be seen that the vanadium and molybdenum recovery rates can reach 95-98% and 96-98% respectively by treating the waste petrochemical catalyst by the method of the present application, and the leaching rate of aluminum in the carrier is less than 0.5%. The aluminum oxide content in the leaching residue after leaching is greater than or equal to 98%, which has high purity and can be directly used as a raw material for preparing a new petrochemical catalyst carrier. The leaching solution obtained has high purity, and the subsequent purification process of vanadium and molybdenum is greatly simplified.

[0072] Comparative Example 1

[0073] The raw material waste petrochemical catalyst treated in the present comparative example is the same as that in Example 1. The method for recovering vanadium and molybdenum in the present comparative example specifically includes the following steps:

[0074] S1: crushing and finely grinding the waste petrochemical catalyst, and obtaining a finely ground residue with a grinding fineness of 85% less than 0.074 mm (i.e. the material with a particle size less than 0.074 mm accounts for 85% of the total material mass);

[0075] The finely ground residue is mixed with an activating agent, which is a mixture of sodium chloride and sodium sulfate, and the amount of the activating agent is 2 times the total molar amount of vanadium and molybdenum in the waste petrochemical catalyst;

[0076] After the finely ground residue is uniformly mixed with the activating agent, it is placed into a microwave roasting device for short-time roasting under the following microwave conditions: microwave power 1000 W, roasting temperature 700°C, and roasting time controlled at 10 min; and a roasted residue is obtained;

[0077] S2: slurrying the roasted residue obtained in step S1 with water to obtain a water-slurried material with a solid-liquid ratio of 0.30 g / mL, and then controlling the temperature for stirring and reaction, with a stirring speed of 200 rpm and a water-slurrying temperature of 75°C, and a stirring time of 20 min;

[0078] After the water-slurrying treatment, solid-liquid separation is performed to obtain a leaching solution containing rare metals vanadium and molybdenum and a leaching residue.

[0079] Analysis shows that, by finely grinding the waste petrochemical catalyst before treatment, the vanadium recovery rate is 38%, the molybdenum recovery rate is 31%, and the aluminum leaching rate is 53%. The aluminum oxide content in the leaching residue is 48%.

[0080] In the leaching solution, the mass fraction of vanadium is 21.36%, the mass fraction of molybdenum is 12.78%, and the mass fraction of aluminum is 65.85%. The composition of the leaching solution is complex, and the purity of vanadium and molybdenum is low.

[0081] The composition of the leaching solution is complex, which increases the difficulty of subsequent process treatment; the aluminum oxide content in the leaching residue after leaching is low, only 48%, and further treatment is required before it can be used as a catalyst carrier raw material.

[0082] By the comparative example, it is shown that the method of treating the waste petrochemical catalyst after being ground has poor effect, mainly because after being ground, the contact reaction area between the alumina and the activating agent is obviously increased, the strong wave-absorbing phase can be transferred to the alumina through heat conduction, causing the temperature of the alumina to increase, and then react with the activating agent, resulting in a significant decrease in the recovery rate of vanadium and molybdenum and a significant increase in the leaching rate of aluminum.

[0083] Comparative Example 2

[0084] The raw material waste petrochemical catalyst treated in the comparative example is the same as in Example 1. The method of recovering vanadium and molybdenum in the comparative example specifically includes the following steps:

[0085] S1: The activating agent (the activating agent is a mixture of sodium chloride and sodium sulfate, and the amount is 2 times the total moles of vanadium and molybdenum in the waste petrochemical catalyst) is mixed with water to form a thick slurry, and then directly added to the granular waste petrochemical catalyst and stirred to mix evenly;

[0086] Then put it into an oven for short-time drying, the drying time is 10 min, and the drying temperature is 100℃;

[0087] After drying, put it into a microwave roasting equipment for short-time roasting, the microwave condition control is: microwave power 1000W, roasting temperature 700℃, roasting time 10 min, to obtain the roasting slag;

[0088] S2: The roasting slag obtained in step S1 is loaded into a filter screen container and washed with circulating water, the number of times of circulating water washing is 5, and the water washing temperature is 75℃, to obtain a leaching solution containing rare metals vanadium and molybdenum and a washing slag.

[0089] After analysis, the recovery rate of vanadium is 68%, the recovery rate of molybdenum is 63%, and the leaching rate of aluminum is 0.8%. The content of alumina in the washing slag is 79%.

[0090] In the leaching solution, the mass fraction of vanadium is 58.63% and the mass fraction of molybdenum is 39.84% based on the total mass of metals, the purity is relatively high, but the overall recovery rate of vanadium and molybdenum is low, the purity of alumina in the leaching slag is low, and it still needs to be further treated before it can be used as a catalyst carrier raw material.

[0091] The comparative example shows that the effect of circulating water washing is not good during water immersion treatment, which is based on the wave-absorbing properties of the sodium chloride and sodium sulfate activating agent, which causes the vanadium and molybdenum products to mainly adhere to the surface of the carrier alumina layer by layer during the microwave roasting process. Directly using the water washing process to treat the roasting slag is difficult to completely strip the vanadium and molybdenum products from the surface of the carrier, thus reducing the recovery rate of vanadium and molybdenum.

[0092] Comparative Example 3

[0093] The raw material waste petrochemical catalyst treated in this comparative example is the same as in Example 1. This comparative example mainly investigates the leaching effect of vanadium and molybdenum in the waste petrochemical catalyst during muffle furnace roasting. The specific treatment steps are as follows:

[0094] S1: Mix the activator (sodium sulfate, the amount of which is 1.2 times the total molar amount of vanadium and molybdenum in the waste petrochemical catalyst) with water to make a viscous slurry, and then directly add the granular waste petrochemical catalyst and stir evenly.

[0095] Then, place it in an oven for short-term drying, with a drying time of 10 minutes and a drying temperature of 100℃;

[0096] After drying, the residue was placed in a muffle furnace for calcination under the following conditions: calcination temperature 700℃, and calcination times of 10 min, 30 min, 60 min, 90 min, 120 min, and 150 min, respectively, to obtain calcined residue.

[0097] S2: The calcined residue obtained in step S1 was mixed with water to form a slurry. The solid-liquid ratio of the water-impregnated material was 0.30 g / mL. Then, the reaction was carried out under controlled temperature and stirring. The stirring speed was 200 rpm, the water impregnation temperature was 75℃, and the stirring time was 20 min.

[0098] After solid-liquid separation, a leachate containing rare metals vanadium and molybdenum and a leachate residue were obtained.

[0099] The leaching results of this comparative example are shown in the table below:

[0100]

[0101] As can be seen from the table above, when using a muffle furnace for roasting, the aluminum leaching rate is high during water leaching, and the resulting leachate has a complex composition, which increases the difficulty of subsequent processing. The alumina content in the leaching residue after leaching is 55-75%, and further processing is required before it can be used as a catalyst carrier raw material.

[0102] Experimental Example 1

[0103] The raw material waste petrochemical catalyst treated in this experimental example is the same as in Example 1. This experimental example mainly investigates the leaching effect of different roasting times on vanadium and molybdenum in the waste petrochemical catalyst under microwave conditions. The specific treatment steps are as follows:

[0104] S1: Mix the activator (sodium chloride, the amount of which is 2.5 times the total molar amount of vanadium and molybdenum in the waste petrochemical catalyst) with water to make a viscous slurry, and then directly add the granular waste petrochemical catalyst and stir evenly.

[0105] Afterwards, short-time drying is carried out in an oven, the drying time is 10 min, and the drying temperature is 100℃;

[0106] After drying, roasting is carried out in a microwave roasting device, the roasting conditions are as follows: the microwave power is 1000W, the roasting temperature is set to 600℃ and 700℃ respectively, and the roasting time is set to 2 min, 4 min, 5 min, 8 min, 10 min and 13 min respectively; and roasting slag is obtained;

[0107] S2: the roasting slag obtained in step S1 is mixed with water, the solid-liquid ratio of the obtained water immersion material is 0.30 g / mL, then temperature-controlled stirring reaction is carried out, the stirring speed is 200 rpm, the water immersion temperature is 75℃, and the stirring time is 20 min;

[0108] Afterwards, solid-liquid separation is carried out, and the leaching solution containing rare metals vanadium and molybdenum and the leaching residue are obtained.

[0109] The leaching experiment results of the present experimental example are shown in the following table:

[0110]

[0111] It can be seen from the above experiments that, during microwave roasting, the roasting time has a significant influence on the leaching of vanadium and molybdenum and aluminum, and the roasting time is preferably controlled to 8-10 min.

[0112] The above examples show that, by using the method of the present application, the rapid recovery of vanadium and molybdenum from waste petrochemical catalysts can be realized, and the effective separation from the carrier metal can also be realized, and the recovery efficiency of vanadium and molybdenum is significantly improved; the obtained leaching residue has high purity and can be directly used as a waste catalyst cylindrical carrier, realizing real recycling and reducing the overall process treatment cost.

Claims

1. A method for recovering vanadium and molybdenum from waste petrochemical catalysts, characterized in that, Including the following steps: Waste petrochemical catalyst is mixed with an activator and then subjected to short-time calcination in a microwave environment to obtain calcined residue. The microwave conditions for the short-time calcination are: microwave power of 1000-1500W and time control of 8-10min; the calcination temperature for the short-time calcination is 600-700℃. The roasted residue was treated with a low-speed stirring water leaching process, followed by solid-liquid separation to obtain a leachate and leachate residue containing rare metals vanadium and molybdenum. The low-speed stirring water immersion process for treating the roasted slag includes: adding water to the roasted slag to prepare a water immersion material, then stirring and reacting under controlled temperature, with the temperature controlled at 60-75℃, the stirring speed controlled at 100-200 rpm, and the water immersion treatment time at 10-20 min. The waste petrochemical catalyst is a waste catalyst with alumina as a carrier, which is mixed with an activator after being deoiled; the activator is sodium chloride and / or sodium sulfate, which is mixed with water to form a viscous slurry and then mixed with the waste petrochemical catalyst; the amount of the activator is 1 to 3 times the total molar amount of vanadium and molybdenum in the waste petrochemical catalyst.

2. The method according to claim 1, characterized in that, The waste petrochemical catalyst is mixed with the activator and then dried for a short time, followed by a short-time calcination; the short-time drying time is 5 to 12 minutes, and the drying temperature is 80 to 110°C.

3. The method according to claim 1, characterized in that, The solid-liquid ratio of the water-immersed material is 0.20–0.40 g / mL.

4. The method according to claim 1, characterized in that, The leaching residue contains ≥98% alumina and is used to prepare petrochemical catalysts.

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