Method for recovering metal in waste catalyst

Abstract

The invention discloses a method for recovering metals in a waste catalyst. The method comprises the following steps: (1) crushing a solid obtained after extraction and oil removal of the molybdenum-nickel waste catalyst; (2) reacting the catalyst powder with chlorine, cooling, and transferring into an anhydrous organic solvent for ultrasonic treatment; separating to obtain a solution I and a material II; (3) mixing the material II with alkali to react, and separating to obtain a solution III and a material IV; and (4) mixing the material IV with acid to react, and separating to obtain a solution V and a material VI. The method disclosed by the invention is free of waste gas emission, environment-friendly and small in pollution, metal elements in the catalyst can be efficiently recovered, and particularly molybdenum, nickel and vanadium in the waste catalyst can be effectively separated. The metal recovery rate can reach 99% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of waste catalyst recovery, and in particular relates to a method for recovering metals in waste hydrogenation catalysts. Background Art

[0002] The large amount of hydrogenation catalyst used and the difficulty in regeneration lead to low metal recycling rate and waste of resources. At present, the basic life of residual oil hydrogenation catalyst is 8,000 hours. Each residual oil hydrogenation unit produces hundreds of tons of waste catalyst every year. China currently has more than a dozen residual oil hydrogenation units, and the annual residual oil waste catalyst can reach tens of thousands of tons. Waste catalyst contains carrier raw materials and active metals. If it is not recycled, it will cause a lot of waste of resources.

[0003] CN113293297A discloses a multi-element recycling method for waste catalysts from residual oil hydrogenation. The multi-element recycling method comprises the following steps: adding a certain proportion of sodium carbonate to the waste catalyst, calcining at high temperature in a rotary kiln, causing a sodiumization reaction, converting valuable metals such as vanadium and molybdenum into soluble salts, and recovering vanadium and molybdenum by a wet process after water immersion; converting the alumina carrier into a soluble salt, separating it from the material, and then controlling the pH and introducing carbon dioxide to make an aluminum hydroxide product; after molybdenum and vanadium are extracted and alumina is removed, nickel in the material is enriched, and then the nickel-rich slag is recovered by a wet process to finally obtain nickelous oxide. The method is suitable for recovering multi-element metals from molybdenum-nickel waste catalysts, but the method has the problems of overly complicated process and high energy consumption in the calcination stage.

[0004] In summary, the existing methods for recycling and reusing hydrogenation catalysts have problems to varying degrees, such as complicated process steps, low recycling rate of active metals and / or carriers, and low activity and short life of the prepared catalysts. Therefore, further in-depth research on the recycling and utilization of spent hydrogenation catalysts is of great significance. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for recovering metals from waste catalysts. The method of the present invention has no waste gas emissions, has low environmental pollution, can efficiently recover metal elements in the catalyst, and can especially effectively separate molybdenum, nickel and vanadium from the waste catalyst. The metal recovery rate in the present invention can reach more than 99%.

[0006] The present invention provides a method for recovering metals from waste catalysts. The method comprises the following steps:

[0007] (1) crushing the solid after extracting and removing oil from the molybdenum-nickel waste catalyst;

[0008] (2) reacting the catalyst powder with chlorine gas, cooling it, transferring it to an anhydrous organic solvent for ultrasonic treatment, and separating to obtain a solution I and a material II;

[0009] (3) mixing material II with a base for reaction, and obtaining solution III and material IV after separation;

[0010] (4) Mixing material IV with an acid for reaction, and obtaining solution V and material VI after separation.

[0011] According to the present invention, the waste hydrogenation catalyst in step (1) is a nickel-molybdenum waste catalyst, that is, a molybdenum-nickel catalyst deactivated after residual oil hydrogenation. The waste hydrogenation catalyst comprises 70% to 90% of catalyst solids and 10% to 30% of petroleum fractions by weight.

[0012] According to the present invention, the waste hydrogenation catalyst after extraction and deoiling in step (1) comprises, based on the mass of the catalyst:

[0013] 10% to 25% molybdenum calculated as molybdenum trioxide;

[0014] 3% to 10% nickel, calculated as nickel oxide;

[0015] 3% to 10% vanadium, calculated as vanadium pentoxide;

[0016] 6% to 14% carbon;

[0017] 41% to 77% carrier alumina.

[0018] According to the present invention, the organic solvent used for extraction in step (1) includes one or more of toluene, petroleum ether, and ethanol; the extraction temperature is 80-110° C., and the extraction time is 60-90 hours. The mass ratio of organic solvent to catalyst is 25-50:1. The extraction is used to remove the petroleum fraction in the nickel-molybdenum waste catalyst.

[0019] According to the present invention, in step (1), the waste hydrogenation catalyst is extracted and then dried and crushed. The drying temperature is 120-200° C. and the drying time is 3-8 hours. The crushing is to crush the waste hydrogenation catalyst to a particle size of 200-500 mesh, preferably 300-400 mesh.

[0020] According to the present invention, the purity of the chlorine gas in step (2) is 96% or more by volume. The flow rate of the chlorine gas in step (2) is 2.7 to 6.8 mL / (min·g catalyst); the reaction conditions are as follows: the reaction temperature is 300 to 400° C., and the reaction time is 40 to 90 min.

[0021] According to the present invention, in step (2), the mixture is cooled to a temperature required for ultrasonic treatment. The anhydrous organic solvent is one or more selected from acetone, tetrahydrofuran, and acetic acid. The mass ratio of the anhydrous organic solvent to the catalyst powder is 3 to 5:1.

[0022] According to the present invention, the ultrasonic frequency in step (2) is 10KHz to 150KHz, the ultrasonic treatment temperature is 20°C to 70°C, and the treatment time is 0.5 to 2h.

[0023] According to the present invention, the alkali in step (3) is sodium hydroxide. The alkali exists in the form of an alkaline solution. The mass concentration of the alkaline solution is 2wt% to 15wt%, preferably 4wt% to 10wt%. The liquid-solid mass ratio of the alkaline solution to the material II is 1 to 5:1, preferably 2 to 4:1. Further, before mixing, the alkaline solution can be heated to 30 to 90°C, preferably 50 to 80°C. The reaction temperature of the mixing reaction in step (3) is 100 to 120°C, and the reaction time is 2 to 4h.

[0024] According to the present invention, the acid in step (4) is at least one of sulfuric acid and nitric acid; the acid exists in the form of an acid solution. The molar concentration of the acid solution is 1.5 to 3 mol / L. The liquid-solid mass ratio of the acid solution to the material IV is 3 to 7:1, preferably 4 to 6:1. Further, before mixing, the acid solution can be heated to 70 to 90°C, preferably 80 to 90°C. The reaction temperature of the mixing reaction in step (4) is 90 to 100°C, and the reaction time is 2 to 3h.

[0025] According to the present invention, preferably, the solution V in step (4) can also be concentrated and crystallized, and centrifuged to obtain material VII. Solution V is a nickel sulfate solution. Material VII is the obtained nickel sulfate crystals. The concentrated crystallization is carried out at a temperature of 26 to 60° C. and a pH of 2.0 to 4.0. The crystallization time is 12 to 16 hours. Sulfuric acid can be used to adjust the pH of the solution.

[0026] According to the present invention, preferably, in step (4), material VI can also be subjected to oxidative calcination to obtain material VIII. Material VI is a vanadium-rich residue, and material VIII obtained by oxidative calcination is vanadium pentoxide. The temperature of the oxidative calcination is 500-550° C., and the time of the oxidative calcination is 120-240 min.

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

[0028] In the method of the present invention, by controlling the reaction conditions, the catalyst powder can react with chlorine, and molybdenum can be simply and highly selectively extracted from the catalyst and transferred to the solution phase (solution I). Then, the separated solid material is mixed with an alkali to obtain a liquid phase containing sodium aluminate. The solid material after the reaction with the alkali is mixed with an acid to separate a nickel salt-containing solution and a vanadium-rich residue. Further, the nickel salt-containing solution is concentrated and crystallized, and centrifuged to obtain a nickel sulfate product; the vanadium-rich residue is oxidized and calcined to obtain a vanadium pentoxide product. The method of the present invention has no waste gas emissions, low environmental pollution, and can efficiently recover metal elements in the catalyst, especially can effectively separate molybdenum, nickel and vanadium in the waste catalyst. The metal recovery rates of molybdenum, nickel and vanadium in the present invention can all reach more than 99%. DETAILED DESCRIPTION

[0029] The effects and effects of the present invention are further illustrated below by way of examples, but the following examples do not constitute a limitation of the method of the present invention.

[0030] In the present invention, % refers to mass fraction unless otherwise specified.

[0031] XRF characterization: The sample composition was analyzed using a Rigaku ZSX100e X-ray fluorescence spectrometer. The target material was Rh. The optical path atmosphere was vacuum conditions.

[0032] In the present invention, the waste hydrogenation catalyst used in each example comprises 85% of catalyst solids and 15% of petroleum fractions.

[0033] In the present invention, the extraction and deoiling conditions in each example are: the organic solvent is toluene, the extraction temperature is 100°C, and the extraction time is 72h. The composition of the waste hydrogenation catalyst after extraction and deoiling is:

[0034] 19.2% molybdenum as molybdenum trioxide;

[0035] 8.6% nickel, calculated as nickel oxide;

[0036] 4.2% vanadium as vanadium pentoxide;

[0037] 9.1% carbon,

[0038] The balance is carrier alumina.

[0039] In the present invention, the metal element recovery rate test instrument is the Agilent 5110 vertical torch bidirectional observation inductively coupled plasma emission spectrometer (ICP-OES). Accurately weigh 0.2g of the catalyst powder before and after the reaction, add 20ml of 1:1 hydrochloric acid and heat on a 270℃ hot plate until the sample is dissolved, and then test the content of each metal element before and after the reaction on the machine after the volume is fixed in a 100ml volumetric flask, thereby obtaining the recovery rate of the metal element.

[0040] The content of each metal element is calculated according to the following formula:

[0041]

[0042] Where: C i —Concentration of element i in the sample solution, mg / L;

[0043] V—total volume of sample solution, mL;

[0044] F—sample dilution multiple;

[0045] m—mass of sample, g;

[0046] ω i —Content of metal i element, μg / g.

[0047] The recovery rate of each metal element is calculated as follows:

[0048]

[0049] Where: i1 —Content of metal i element before reaction, μg / g;

[0050] ω i2 —Content of metal i element after reaction, μg / g.

[0051] Example 1

[0052] (1) Take the spent hydrogenation catalyst after industrial operation, extract and remove oil, dry it at 150°C for 5 hours, and then crush it into 300 mesh.

[0053] (2) 124 g of catalyst powder was placed in a container, and 6.3 mL / (min·g catalyst) of 98% purity chlorine gas was introduced for reaction at a temperature of 400° C. and a reaction time of 50 min. The reacted catalyst was cooled to 30° C., then transferred to 434 g of acetone and mixed evenly, and then placed in an ultrasonic generator, with acetone as the medium, and treated at 30° C. and an ultrasonic frequency of 50 KHz for 1 hour, and separated to obtain solution I and material II, respectively. Among them, material II was 100 g.

[0054] (3) Add material II to 220 g of 10 wt% sodium hydroxide solution at 70°C, then heat to 110°C and keep warm for 3 hours, with a liquid-to-solid mass ratio of 2.2:1. Filter to obtain solution III and material IV.

[0055] (4) Using 40 g of 2.5 mol / L sulfuric acid solution at 80° C. to leaching material IV (liquid-solid mass ratio is 4:1), filtering to obtain solution V and material VI. Solution V is a nickel sulfate solution. Material VI is a vanadium-rich residue.

[0056] (5) The nickel sulfate solution of solution V is heated to 30° C., sulfuric acid is added to adjust the pH value of the solution to 3.0, and concentrated and crystallized. After crystallization for 12 hours, centrifugal separation is performed to obtain a nickel sulfate product; the vanadium-rich residue of material VI is calcined at 520° C. for 150 minutes to obtain a vanadium pentoxide product.

[0057] After analysis: the recovery rate of molybdenum reached 99.8wt%, the recovery rate of nickel reached 99.7wt%, and the recovery rate of vanadium reached 99.1wt%.

[0058] Example 2

[0059] (1) Take the spent hydrogenation catalyst after industrial operation, extract and remove oil, dry it at 120°C for 6 hours, and then crush it to 350 mesh.

[0060] (2) 124 g of catalyst powder was placed in a container, and 4.5 mL / (min·g catalyst) of 98% purity chlorine gas was introduced for reaction. The reaction temperature was 350°C and the reaction time was 70 min. The reacted catalyst was cooled to 30°C and then transferred to 500 g of acetone. After being mixed evenly, it was placed in an ultrasonic generator, with acetone as the medium, and treated at 60°C and an ultrasonic frequency of 100 KHz for 0.5 hours. After separation, solution I and material II were obtained respectively. Among them, material II was 100 g.

[0061] (3) Add material II to 300 g of 8 wt% sodium hydroxide solution at 80°C, then heat to 120°C and keep warm for 2.5 hours. The liquid-to-solid mass ratio is 3:1. Filter to obtain solution III and material IV.

[0062] (4) Using 60 g of 1.5 mol / L sulfuric acid solution at 85° C. to leaching material IV (liquid-solid mass ratio is 6:1), filtering to obtain solution V and material VI. Solution V is a nickel sulfate solution. Material VI is a vanadium-rich residue.

[0063] (5) The nickel sulfate solution of solution V is heated to 50° C., sulfuric acid is added to adjust the pH value of the solution to 3.5, and concentrated and crystallized. After crystallization for 16 hours, centrifugal separation is performed to obtain a nickel sulfate product; the vanadium-rich residue of material VI is calcined at 500° C. for 240 minutes to obtain a vanadium pentoxide product.

[0064] After analysis: the recovery rate of molybdenum reached 99.7wt%, the recovery rate of nickel reached 99.5wt%, and the recovery rate of vanadium reached 99.0wt%.

[0065] Example 3

[0066] (1) Take the spent hydrogenation catalyst after industrial operation, extract and remove oil, dry it at 160℃ for 4h, and then crush it into 300 mesh.

[0067] (2) 124 g of catalyst powder was placed in a container, and 6.3 mL / (min·g catalyst) of 98% purity chlorine gas was introduced for reaction at a temperature of 400° C. and a reaction time of 50 min. The catalyst after reaction was cooled to 30° C., then transferred to 520 g of tetrahydrofuran and mixed evenly, and then placed in an ultrasonic generator, with tetrahydrofuran as the medium, and treated at 30° C. and an ultrasonic frequency of 90 KHz for 1 hour, and separated to obtain solution I and material II, respectively. Among them, material II was 100 g.

[0068] (3) Add material II to 220 g of 10 wt% sodium hydroxide solution at 60°C, then heat to 120°C and keep warm for 4 hours, with a liquid-to-solid mass ratio of 2.2:1. Filter to obtain solution III and material IV.

[0069] (4) Using 40 g of 2.5 mol / L sulfuric acid solution at 80° C. to leaching material IV (liquid-solid mass ratio is 4:1), filtering to obtain solution V and material VI. Solution V is a nickel sulfate solution. Material VI is a vanadium-rich residue.

[0070] (5) The nickel sulfate solution of solution V is heated to 40°C, and sulfuric acid is added to adjust the pH value of the solution to 3.0, and then concentrated and crystallized. After crystallization for 14 hours, centrifugal separation is performed to obtain a nickel sulfate product; the vanadium-rich residue of material VI is calcined at 500°C for 240 minutes to obtain a vanadium pentoxide product.

[0071] After analysis: the recovery rate of molybdenum reached 99.7wt%, the recovery rate of nickel reached 99.8wt%, and the recovery rate of vanadium reached 99.2wt%.

[0072] Example 4

[0073] (1) Take the spent hydrogenation catalyst after industrial operation, extract and remove oil, dry it at 150°C for 5 hours, and then crush it into 400 mesh.

[0074] (2) 124 g of catalyst powder was placed in a container, and 3.5 mL / (min·g catalyst) of 98% purity chlorine gas was introduced for reaction at a temperature of 380° C. and a reaction time of 90 min. The reacted catalyst was cooled to 30° C., then transferred to 500 g of acetic acid and mixed evenly, and then placed in an ultrasonic generator, with acetic acid as the medium, and treated at 70° C. and an ultrasonic frequency of 50 KHz for 2 hours, and separated to obtain solution I and material II, respectively. Among them, material II was 100 g.

[0075] (3) Add material II to 400 g of 5 wt% sodium hydroxide solution at 80°C, then heat to 110°C and keep warm for 3 hours, with a liquid-to-solid mass ratio of 4:1. Filter to obtain solution III and material IV.

[0076] (4) Using 50 g of 2.0 mol / L sulfuric acid solution at 90° C. to leaching material IV (liquid-solid mass ratio is 5:1), filtering to obtain solution V and material VI. Solution V is a nickel sulfate solution. Material VI is a vanadium-rich residue.

[0077] (5) The nickel sulfate solution of solution V is heated to 60° C., sulfuric acid is added to adjust the pH value of the solution to 4.0, and concentrated and crystallized. After crystallization for 12 hours, centrifugal separation is performed to obtain a nickel sulfate product; the vanadium-rich residue of material VI is calcined at 550° C. for 120 minutes to obtain a vanadium pentoxide product.

[0078] After analysis: the recovery rate of molybdenum reached 99.8wt%, the recovery rate of nickel reached 99.8wt%, and the recovery rate of vanadium reached 99.1wt%.

[0079] Comparative Example 1

[0080] Compared with Example 1, only the chlorine gas in step (2) is replaced by air. The other steps are the same as in Example 1.

[0081] After analysis: After testing, analysis and calculation, the recovery rate of molybdenum in this case reached 66.3wt%, the recovery rate of nickel reached 97.8wt%, and the recovery rate of vanadium reached 17.6wt%.

[0082] The above describes the specific implementation of the present invention in detail, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the various technical features being combined in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for recovering metals from spent catalysts, characterized in that: The steps include: (1) crushing the solid after extracting and removing oil from the molybdenum-nickel waste catalyst; (2) reacting the catalyst powder with chlorine gas, cooling it, and transferring it to an anhydrous organic solvent for ultrasonic treatment; Separating to obtain solution I and material II; (3) mixing material II with a base for reaction, and obtaining solution III and material IV after separation; (4) Mixing material IV with an acid for reaction, and obtaining solution V and material VI after separation.

2. The method according to claim 1, characterized in that: The organic solvent for extraction in step (1) includes one or more of toluene, petroleum ether and ethanol; further, the extraction temperature is 80-110° C. and the extraction time is 60-90 hours.

3. The method according to claim 1, characterized in that: The waste hydrogenation catalyst after extraction and deoiling in step (1) comprises, based on the mass of the catalyst: 10% to 25% molybdenum calculated as molybdenum trioxide; 3% to 10% nickel, calculated as nickel oxide; 3% to 10% vanadium, calculated as vanadium pentoxide; 6% to 14% carbon; 41% to 77% carrier alumina.

4. The method according to claim 1, characterized in that: The flow rate of chlorine gas in step (2) is 2.7-6.8 mL / (min·g catalyst).

5. The method according to claim 1, characterized in that: The reaction conditions in step (2) are as follows: the reaction temperature is 300-400° C., and the reaction time is 40-90 min.

6. The method according to claim 1, characterized in that: The ultrasonic frequency in step (2) is 10KHz to 150KHz, the ultrasonic treatment temperature is 20°C to 70°C, and the treatment time is 0.5 to 2h.

7. The method according to claim 1, characterized in that: The alkali in step (3) is sodium hydroxide; And / or, the alkali is present in the form of an alkali solution; the mass concentration of the alkali solution is 2wt% to 15wt%, preferably 4wt% to 10wt%; And / or, the liquid-solid mass ratio of the alkaline solution to the material II is 1 to 5:1, preferably 2 to 4:

1.

8. The method according to claim 1, characterized in that: The reaction temperature of the mixed reaction in step (3) is 100-120° C., and the reaction time is 2-4 hours.

9. The method according to claim 1, characterized in that: The reaction temperature of the mixed reaction in step (4) is 90-100° C., and the reaction time is 2-3 hours.

10. The method according to claim 1, characterized in that: Step (4) Solution V is concentrated and crystallized, and centrifuged to obtain material VII; further, the concentrated crystallization is carried out at a temperature of 26 to 60° C. and a pH of 2.0 to 4.0, and the crystallization time is 12 to 16 hours; And / or, in step (4), material VI is subjected to oxidative calcination to obtain material VIII; further, the temperature of the oxidative calcination is 500-550° C., and the time of the oxidative calcination is 120-240 min.

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