A method for selectively recovering molybdenum and nickel from spent nickel-molybdenum catalyst

Abstract

The present application relates to a kind of method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst, belong to catalyst recovery technical field.The method of the present application is pretreated after waste nickel-molybdenum catalyst, using sulfuric acid and hydrogen peroxide leaching, using P227 selectively from leaching solution extraction molybdenum, after alkaline reagent back extraction through evaporation crystallization sintering high-purity molybdenum oxide is obtained;Then use the synergistic extractant containing Cyanex301 and TOPO from raffinate extraction Ni, after washing and hydrochloric acid back extraction of nickel-containing organic phase is obtained the enrichment liquid of nickel, then add precipitant, after precipitation sintering, obtain high-purity nickel oxide product.The method is through one step leaching and simultaneously collects molybdenum and nickel, and the recovery rate of molybdenum and nickel is more than 93%, while the purity of product is more than 99.0%, and process operation is simple, energy consumption is low, can fully recover valuable metals in waste catalyst, is an economic saving type, resource friendly type process, widely used in catalyst recovery field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst recovery, in particular to a method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst. BACKGROUND

[0002] Hydrodesulfurization catalysts have been widely used in gasoline, heavy hydrocarbon and petrochemical industry due to their characteristics of reducing sulfur content in oil refining process. However, during long-term use, the catalyst loses its active ingredients, and heavy metals and carbon are deposited on the surface of the catalyst, which reduces its catalytic activity and becomes a toxic waste. According to statistics, more than 120,000 tons of hydrodesulfurization catalysts are discarded by the global petrochemical industry every year. Improper disposal of these waste catalysts not only poses a potential serious threat to the ecological environment and human health, but also leads to the loss of a large amount of valuable metals. Waste catalysts contain valuable metals such as molybdenum, nickel, cobalt and vanadium, among which the molybdenum content is more than 10%, and the nickel content is about 1%-8%. These valuable metals are important strategic resources for the country. Therefore, recycling waste hydrodesulfurization catalysts not only can reduce environmental pollution, but also can alleviate the pressure of shortage of important national resources, and at the same time can obtain certain economic benefits, which has important research value.

[0003] Currently, the research on waste catalyst recovery process in China mostly focuses on the recovery of single metal such as molybdenum, and the research on comprehensive recovery process of double metal and multi-metal is less and in the initial stage. CN102041388A discloses a method for recovering metals from waste catalyst containing molybdenum and nickel. The method mixes the calcined molybdenum-nickel catalyst with alkaline substances and continues to calcine, and then uses acid substances to leach and filter the obtained powder to obtain a filtrate. The filtrate is treated by precipitation method to obtain ammonium molybdate precipitate, aluminum hydroxide precipitate and nickel precipitate in turn, and the crude product is treated again to obtain ammonium molybdate product and nickel sulfate product. However, the method is complex in operation, and the use in production will greatly increase the operation cost, and the recovery rate and purity of the obtained molybdenum and nickel products are low. CN106222418A discloses a comprehensive process for recovering molybdenum, nickel, bismuth and cobalt from waste catalyst. The method first treats the waste catalyst by alkali leaching to obtain a molybdenum-containing leaching solution and a leaching residue. The molybdenum-containing leaching solution is converted into ammonium heptamolybdate product by acid precipitation and ammonia water. The leaching residue is leached by nitric acid to obtain a solution containing bismuth, cobalt and nickel, and then the bismuth oxide nitrate precipitate, high cobalt sulfate and nickel carbonate products are obtained in turn by precipitation method. Although the method can recover multiple metals at the same time, it needs two steps of leaching, and the direct recovery rate of each element is low. CN113789446A discloses a method for recovering molybdenum, vanadium and nickel from waste catalyst. The method calcines the waste catalyst in advance, then calcines the pretreated waste catalyst with alkaline solution, and then leaches with deionized water under ultrasonic to obtain a leaching solution containing aluminum, vanadium and molybdenum and a leaching residue. After the leaching solution is separated from aluminum by precipitation method, ammonium chloride is added to obtain ammonium metavanadate solid, and after calcination, vanadium pentoxide is obtained. Then the remaining molybdenum is recovered by a composite material. After the leaching residue is extracted by an organic acid, nickel is recovered by a new composite material. However, the method needs to calcine the waste catalyst, which has high operating temperature, high energy consumption and produces toxic gas. At the same time, multiple leaching operations are needed, which increases the complexity of the process.

[0004] Therefore, it is necessary to develop a method for comprehensive recovery of noble metals molybdenum and nickel from waste catalyst, which is simple in operation, green and environmentally friendly, and has high metal recovery rate. SUMMARY

[0005] The purpose of the present application is to provide a method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst, which can not only selectively recover molybdenum and nickel, but also has a recovery rate of molybdenum and nickel of more than 93% under optimal conditions, and the purity of the obtained molybdenum oxide and nickel oxide products is more than 99%. At the same time, the method only needs one step of leaching, and molybdenum and nickel can be recovered by extraction method, which reduces the operation steps and types of equipment, and greatly reduces the process cost.

[0006] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0007] The application provides a method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst, comprising the following steps:

[0008] Step 1, washing the waste nickel-molybdenum catalyst with a detergent to remove organic components on the surface of the catalyst, drying, crushing and sieving, and then storing;

[0009] Step 2, preparing a mixed acidic leaching solution containing sulfuric acid and hydrogen peroxide;

[0010] Step 3, mixing the powder of step 1 with the mixed acidic leaching solution of step 2 for leaching, and filtering to obtain a leaching solution;

[0011] Step 4, adjusting the leaching solution of step 3 to pH = 0-1 with sulfuric acid, and using an extractant, i.e., a solution of di(2-ethylhexyl) phosphinic acid (P227), for single-stage or multi-stage countercurrent extraction, and separating to obtain a first raffinate and a molybdenum-containing loaded organic phase; the molybdenum-containing loaded organic phase is back-extracted with an alkaline solution to obtain a back-extraction solution 1; the back-extraction solution 1 is concentrated by evaporation and then sintered to obtain molybdenum oxide;

[0012] Step 5, adjusting the first raffinate of step 4 to pH = 1-3 with an ammonia solution, and using an extractant, i.e., bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex 301), for single-stage or multi-stage countercurrent extraction, and separating to obtain a second raffinate and a nickel-containing organic phase; the nickel-containing organic phase is back-extracted with a hydrochloric acid solution to obtain a back-extraction solution 2; a precipitant is added to the back-extraction solution 2 for precipitation and sintering reaction to obtain nickel oxide.

[0013] In the above technical solution, preferably, the detergent in step 1 is acetone, carbon tetrachloride, or methane, etc., the drying temperature is 80-100℃, and the particle size of the crushed catalyst is between 50-200 meshes.

[0014] In the above technical solution, preferably, the concentration of sulfuric acid in the mixed acidic leaching solution in step 2 is 0.5-1.5 mol / L, and the concentration of hydrogen peroxide is 3-8 wt.%.

[0015] In the above technical solution, preferably, the leaching conditions in step 3 are as follows: the reaction temperature is 25-35℃, the leaching time is 20-30 min, and the liquid-solid ratio is (0.1-1 g):10 mL.

[0016] In the above technical solution, preferably, the extractant in step 4 is a solution of di(2-ethylhexyl) phosphinic acid (P227) with a concentration of 0.3-1 mol / L, and the extraction conditions are as follows: the phase ratio of the organic phase to the aqueous phase (O:A) is (0.2-5):1, the extraction temperature is 25-35℃, and the extraction time is 10-30 min.

[0017] In the above technical solution, preferably, the basic solution used in the back extraction in step 4 is ammonia, sodium hydroxide solution, ammonium carbonate solution, or ammonium hydrogen carbonate solution, etc., and the back extraction conditions are: the concentration of the basic solution is 0.4-1 mol / L, the phase ratio (O:A) of the organic phase and the aqueous phase is (0.33-5):1, the back extraction temperature is 25-35℃, and the back extraction time is 10-30 min.

[0018] In the above technical solution, preferably, the sintering temperature in step 4 is 500℃, and the sintering time is 2h.

[0019] In the above technical solution, preferably, the extractant in step 5 is a synergistic extractant composed of bis(2,4,4-trimethylpentyl) dithiophosphonic acid (Cyanex 301) and tri-n-octyl phosphine oxide (TOPO), and the composition of the extractant is: the concentration of Cyanex 301 is 0.3-0.6 mol / L, and the concentration of TOPO is 0-0.3 mol / L; and the extraction conditions are: the phase ratio (O:A) of the organic phase and the aqueous phase is (0.14-3):1, the extraction temperature is 25-35℃, and the extraction time is 10-30 min.

[0020] In the above technical solution, preferably, the concentration of the hydrochloric acid solution in step 5 is 8-10 mol / L, and the specific back extraction conditions are: the phase ratio (O:A) of the organic phase and the aqueous phase is (0.25-4):1, the back extraction temperature is 25-35℃, and the back extraction time is 10-20 min.

[0021] In the above technical solution, preferably, the precipitant added in the back extraction solution 2 in step 5 is ammonia, sodium hydroxide, ammonium oxalate, etc., and the sintering temperature is 300-500℃.

[0022] The beneficial effects of the present application are:

[0023] The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalysts has the advantages of simple process operation, low energy consumption, and high product purity, and can obtain a leaching solution containing molybdenum and nickel through one-step leaching operation, and can recover molybdenum and nickel through extraction, with a recovery rate of more than 93%, and a purity of more than 99%, which is an economical and environment-friendly recovery process. In the process, sulfuric acid and hydrogen peroxide mixed leaching agent is used to extract the waste catalyst, which has a low operating temperature and low energy consumption compared with the commonly used alkali roasting method, and the leaching rates of molybdenum and nickel are both more than 94%, while the leaching rate of impurity aluminum is less than 15%. In addition, P227 is used as the molybdenum extractant in the process, which basically does not extract nickel, aluminum, iron, etc., so that a high-purity molybdenum-rich solution can be obtained, and the extraction phase separation time is short and the interface phenomenon is good. The present application uses Cyanex 301+TOPO synergistic extractant to recover nickel in the raffinate, which not only greatly improves the extraction capacity of nickel, but also reduces the back extraction liquid acidity during back extraction, so that the nickel-containing loaded organic phase can be completely back extracted. Attached Figure Description

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 This is a process flow diagram of the method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalysts according to the present invention.

[0026] Figure 2 The images show the XRD patterns of the molybdenum oxide product and standard sample from Example 2, where: a1 is the XRD pattern of the molybdenum oxide product, and b1 is the standard XRD pattern of the molybdenum oxide sample.

[0027] Figure 3 The XRD patterns of the nickel oxide product and standard sample in Example 2 are shown below, where: a2 is the XRD pattern of the nickel oxide product and b2 is the standard pattern of the nickel oxide sample. Detailed Implementation

[0028] To better understand the present invention, the present invention will be further described below with reference to specific embodiments.

[0029] Example 1

[0030] Combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalysts according to the present invention includes the following steps:

[0031] Step 1: Wash the waste nickel-molybdenum catalyst three times with acetone to remove the organic components on its surface. After washing with water, dry it at 80°C to remove the residual moisture in the catalyst. Then, pulverize it into 100-mesh powder and store it in a desiccator for later use.

[0032] Step 2: Prepare a mixed acidic leachate containing sulfuric acid and hydrogen peroxide, wherein the sulfuric acid concentration is 0.5 mol / L and the hydrogen peroxide concentration is 4 wt.%.

[0033] Step 3: Mix the powder from Step 1 with the mixed acidic leachate from Step 2 and leach under the following conditions: reaction temperature 25℃, leaching time 20 min, and liquid-to-solid ratio 0.5 g: 10 mL. Filter to obtain the leachate. The composition of the leachate is shown in the table below:

[0034]

[0035] Step 4, the leaching solution of step 3 is adjusted to pH = 0.5 with sulfuric acid, and three-stage countercurrent extraction is performed using 0.3 mol / L P227, with the extraction conditions being: temperature 25℃, extraction time 30 min, phase ratio O:A = 1:3; after separation, a first raffinate and a loaded organic phase containing molybdenum are obtained, and the loaded organic phase containing molybdenum contains 15.76 g / L Mo. After washing the loaded organic phase containing molybdenum with 0.1 mol / L sulfuric acid, three-stage countercurrent stripping is performed using 0.4 mol / L ammonium carbonate solution, with the stripping conditions being: temperature 25℃, time 30 min, phase ratio O:A = 3:1; after separation, a first stripping solution is obtained, and the first stripping solution contains 46.56 g / L Mo. The first stripping solution is concentrated by evaporation to obtain ammonium molybdate, and the ammonium molybdate is sintered in a muffle furnace at 500℃ for 2h to obtain a molybdenum oxide product.

[0036] Step 5, after the first raffinate of step 4 is adjusted to pH = 3 using an ammonia solution, single-stage extraction is performed using 0.45 mol / L of a synergistic extractant ([Cyanex301]:[TOPO] molar concentration = 5:1), with the extraction conditions being: temperature 25℃, extraction time 20 min, phase ratio O:A = 1:5; after separation, a second raffinate and a nickel-containing organic phase are obtained, and the nickel-containing organic phase contains 3.95 g / L Ni. The nickel-containing organic phase is first washed twice with 1M hydrochloric acid, and then stripped with 10M hydrochloric acid solution to obtain a second stripping solution, with the stripping conditions being: temperature 25℃, time 20 min, phase ratio O:A = 3:1. Ammonium oxalate solution is added to the second stripping solution, with the ammonium oxalate solution containing 0.5 mol / L ammonium oxalate and 0.5 mol / L hydrochloric acid, and the pH of the second stripping solution is adjusted to 1.5. After stirring for 1h at 50℃, a nickel oxalate solid is obtained by filtration. The nickel oxalate solid is dried and placed in a muffle furnace, and sintered at 400℃ for 1h to obtain a nickel oxide sample. The precipitation pH is 1.5, the temperature is 50℃, and the precipitation time is 1h, and a nickel oxalate solid is obtained after filtration. The nickel oxalate solid is dried and placed in a muffle furnace, and sintered at 400℃ for 1h to obtain a nickel oxide sample.

[0037] In this embodiment, the recovery rate of molybdenum is 94.1%, and the purity of the molybdenum oxide product is 99.9%. The recovery rate of nickel is 91.63%, and the purity of the nickel oxide product is 97.5%.

[0038] Example 2

[0039] In combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application comprises the following steps:

[0040] Step 1, the waste nickel-molybdenum catalyst is washed three times with acetone to remove organic components on its surface, washed with water, dried at 80℃ to remove residual water in the catalyst, and then crushed into 100 mesh powder and stored in a desiccator for subsequent use.

[0041] Step 2, a mixed acid leaching solution containing sulfuric acid and hydrogen peroxide is prepared, with the sulfuric acid concentration being 0.5 mol / L and the hydrogen peroxide concentration being 4wt.%.

[0042] Step 3, the powder of step 1 was mixed with the mixed acid leaching solution of step 2, and the leaching conditions were as follows: the reaction temperature was 25°C, the leaching time was 20 min, and the liquid-solid ratio was 0.5 g:10 mL. The leaching solution was filtered, and the composition of the leaching solution was as shown in the following table:

[0043]

[0044] Step 4, the leaching solution of step 3 was adjusted to pH=0.5 with sulfuric acid, and three-stage countercurrent extraction was performed using 0.3 mol / L P227, and the extraction conditions were as follows: the temperature was 25°C, the extraction time was 30 min, and the phase ratio O:A=1:3. After separation, the first raffinate and the loaded organic phase containing molybdenum were obtained, and the loaded organic phase containing molybdenum contained 15.76 g / L Mo. After washing the loaded organic phase containing molybdenum with 0.1 mol / L sulfuric acid, three-stage countercurrent stripping was performed using 0.4 mol / L ammonium carbonate solution, and the stripping conditions were as follows: the temperature was 25°C, the time was 30 min, and the phase ratio O:A=3:1. After separation, the stripping solution 1 was obtained, and the stripping solution 1 contained 46.56 g / L Mo. The stripping solution 1 was concentrated by evaporation treatment to obtain ammonium molybdate, and the ammonium molybdate was sintered in a muffle furnace at 500°C for 2 h to obtain a molybdenum oxide product.

[0045] Step 5, after the first raffinate of step 4 was adjusted to pH=1 using an ammonia solution, three-stage countercurrent extraction was performed using 0.45 mol / L of a synergistic extractant ([Cyanex301]:[TOPO]=5:1), and the extraction conditions were as follows: the temperature was 25°C, the extraction time was 20 min, and the phase ratio O:A=1:5. After separation, the second raffinate and the organic phase containing nickel were obtained, and the organic phase containing nickel contained 4.01 g / L Ni. The organic phase containing nickel was washed twice with 1M hydrochloric acid, and after stripping with a 9M hydrochloric acid solution, the stripping solution 2 was obtained, and the stripping conditions were as follows: the temperature was 25°C, the time was 20 min, and the phase ratio O:A=3:1. Ammonium oxalate solution was added to the stripping solution 2, and the amount of the ammonium oxalate solution was calculated according to the following formula: The precipitation pH was 1.5, the temperature was 50°C, and the precipitation time was 1 h. After filtration, the nickel oxalate solid was obtained. The nickel oxalate solid was dried and placed in a muffle furnace, and sintered at 400°C for 1 h to obtain a nickel oxide sample.

[0046] In this example, the recovery rate of molybdenum was 94.1%, the purity of the molybdenum oxide product was 99.9%, and the XRD patterns of the molybdenum oxide product and the standard sample are shown in Figure 1 . The recovery rate of nickel was 93.1%, the purity of the nickel oxide product was 99.0%, and the XRD patterns of the nickel oxide product and the standard sample are shown in Figure 2 .

[0047] Example 3

[0048] Combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application is specifically described as follows:

[0049] Step 1, the waste nickel-molybdenum catalyst is washed with carbon tetrachloride for three times to remove the organic components on the surface, and then dried at 80℃ after water washing to remove the residual water in the catalyst, and then crushed into 100 mesh powder and stored in a desiccator for subsequent use.

[0050] Step 2, a mixed acid leaching solution containing sulfuric acid and hydrogen peroxide is prepared, wherein the concentration of sulfuric acid is 0.5 mol / L and the concentration of hydrogen peroxide is 3 wt.%.

[0051] Step 3, the powder of step 1 is mixed with the mixed acid leaching solution of step 2 for leaching, and the leaching conditions are as follows: the reaction temperature is 25℃, the leaching time is 20 min, and the liquid-solid ratio is 0.5 g:10 mL. The leaching solution is obtained by filtration, and the composition of the leaching solution is shown in the following table:

[0052]

[0053] Step 4, the leaching solution of step 3 is adjusted to pH=0.5 with sulfuric acid, and three-stage countercurrent extraction is carried out using 0.3 mol / L P227, and the extraction conditions are as follows: the temperature is 25℃, the extraction time is 30 min, and the phase ratio O:A=1:3. After separation, the first raffinate and the molybdenum-containing loaded organic phase are obtained, and the molybdenum-containing loaded organic phase contains 15.59 g / L Mo. The molybdenum-containing loaded organic phase is washed with 0.1 mol / L sulfuric acid, and then three-stage countercurrent stripping is carried out using 0.4 mol / L ammonium carbonate solution, and the stripping conditions are as follows: the temperature is 25℃, the time is 30 min, and the phase ratio O:A=3:1. After separation, the stripping solution 1 is obtained, and the stripping solution 1 contains 46.40 g / L Mo. The stripping solution 1 is concentrated by evaporation to obtain ammonium molybdate, and the ammonium molybdate is sintered in a muffle furnace at 500℃ for 2h to obtain molybdenum oxide product.

[0054] Step 5, after the first raffinate of step 4 is adjusted to pH=1 using an ammonia solution, three-stage countercurrent extraction is carried out using 0.45 mol / L synergistic extractant ([Cyanex301]:[TOPO] molar concentration=5:1), and the extraction conditions are as follows: the temperature is 25℃, the extraction time is 20 min, and the phase ratio O:A=1:5. The second raffinate and the nickel-containing organic phase are obtained by separation, and the nickel-containing organic phase contains 3.92 g / L Ni. The nickel-containing organic phase is first washed twice with 1M hydrochloric acid, and then stripped with 9M hydrochloric acid solution to obtain stripping solution 2, and the stripping conditions are as follows: the temperature is 25℃, the time is 20 min, and the phase ratio O:A=3:1. Ammonium oxalate solution is added to the stripping solution 2, and the concentration of the ammonium oxalate solution is 0.5 mol / L. The precipitated nickel oxalate solid was dried and placed in a muffle furnace, sintered at 400°C for 1 h to obtain a nickel oxide sample.

[0055] In this embodiment, the recovery rate of molybdenum was 93.51%, and the purity of the molybdenum oxide product was 99.9%. The recovery rate of nickel was 91.35%, and the purity of the nickel oxide product was 99.1%.

[0056] Example 4

[0057] In combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application is described in detail as follows:

[0058] Step 1. The waste nickel-molybdenum catalyst was washed with carbon tetrachloride three times to remove the organic components on its surface, then dried at 80°C after water washing to remove the residual water in the catalyst, and then crushed into 100 mesh powder and stored in a desiccator for subsequent use.

[0059] Step 2. A mixed acid leaching solution containing sulfuric acid and hydrogen peroxide was prepared, wherein the concentration of sulfuric acid was 0.5 mol / L, and the concentration of hydrogen peroxide was 5 wt.%.

[0060] Step 3. The powder of step 1 was mixed with the mixed acid leaching solution of step 2 for leaching, and the leaching conditions were as follows: the reaction temperature was 25°C, the leaching time was 20 min, and the liquid-solid ratio was 0.5 g:10 mL. The leaching solution was obtained by filtration, and the composition of the leaching solution is shown in the following table:

[0061]

[0062] Step 4. The leaching solution of step 3 was adjusted to pH=0.5 with sulfuric acid, and three-stage countercurrent extraction was performed using 0.3 mol / L P227, and the extraction conditions were as follows: the temperature was 25°C, the extraction time was 30 min, and the phase ratio O:A was 1:3. After separation, the first raffinate and a molybdenum-containing loaded organic phase were obtained, and the molybdenum-containing loaded organic phase contained 15.90 g / L Mo. The molybdenum-containing loaded organic phase was washed with 0.1 mol / L sulfuric acid, and then three-stage countercurrent stripping was performed using 0.4 mol / L ammonium carbonate solution, and the stripping conditions were as follows: the temperature was 25°C, the time was 30 min, and the phase ratio O:A was 3:1. After separation, stripping solution 1 was obtained, which contained 47.19 g / L Mo. Ammonium molybdate was obtained by evaporation and concentration treatment of stripping solution 1, and the ammonium molybdate was sintered at 500°C in a muffle furnace for 2 h to obtain a molybdenum oxide product.

[0063] Step 5, the first raffinate of step 4 was adjusted to pH = 1 using ammonia solution, and then was subjected to three-stage countercurrent extraction using 0.45 mol / L synergistic extractant ([Cyanex301]:[TOPO] = 5:1 in molar concentration) under the following conditions: temperature 25°C, extraction time 20 min, phase ratio O:A = 1:5; a second raffinate and a nickel-containing organic phase were obtained by liquid separation, and the nickel-containing organic phase contained 4.08 g / L Ni. The nickel-containing organic phase was first washed twice with 1 M hydrochloric acid, and then was subjected to stripping with 9 M hydrochloric acid solution to obtain a stripping solution 2, under the following conditions: temperature 25°C, time 20 min, phase ratio O:A = 3:1. Ammonium oxalate solution was added to the stripping solution 2, wherein The precipitation pH was 1.5, the temperature was 50°C, the precipitation time was 1 h, and a nickel oxalate solid was obtained after filtration. The nickel oxalate solid was dried and placed in a muffle furnace, and was sintered at 400°C for 1 h to obtain a nickel oxide sample.

[0064] In this embodiment, the recovery rate of molybdenum was 95.33%, and the purity of the molybdenum oxide product was 99.8%. The recovery rate of nickel was 94.6%, and the purity of the nickel oxide product was 98.9%.

[0065] Example 5

[0066] In combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application comprises the following steps:

[0067] Step 1, the waste nickel-molybdenum catalyst was washed with acetone three times to remove the organic components on the surface, and was dried at 80°C after water washing to remove the residual water in the catalyst, and then was crushed into a 100-mesh powder and stored in a desiccator for subsequent use.

[0068] Step 2, a mixed acid leaching solution containing sulfuric acid and hydrogen peroxide was prepared, wherein the concentration of sulfuric acid was 0.5 mol / L, and the concentration of hydrogen peroxide was 4 wt.%.

[0069] Step 3, the powder of step 1 was mixed with the mixed acid leaching solution of step 2 for leaching, under the following conditions: reaction temperature 25°C, leaching time 20 min, liquid-solid ratio 0.5 g:10 mL. A leaching solution was obtained by filtration, and the composition of the leaching solution is shown in the following table:

[0070]

[0071] Step 4, the leaching solution of step 3 is adjusted to pH = 0 with sulfuric acid, and three-stage countercurrent extraction is performed using 0.5 mol / L P227, with the extraction conditions being: temperature 25°C, extraction time 30 min, phase ratio O:A = 1:3; after separation, a first raffinate and a loaded organic phase containing molybdenum are obtained, the loaded organic phase containing molybdenum contains 15.63 g / L Mo. The loaded organic phase containing molybdenum is washed with 0.1 mol / L sulfuric acid, and then three-stage countercurrent stripping is performed using 0.4 mol / L ammonium carbonate solution, with the stripping conditions being: temperature 25°C, time 30 min, phase ratio O:A = 3:1; after separation, a stripping solution 1 is obtained, which contains 45.99 g / L Mo. The stripping solution 1 is concentrated by evaporation to obtain ammonium molybdate, and the ammonium molybdate is sintered in a muffle furnace at 500°C for 2 h to obtain a molybdenum oxide product.

[0072] Step 5, after the first raffinate of step 4 is adjusted to pH = 1 using an aqueous ammonia solution, three-stage countercurrent extraction is performed using 0.45 mol / L of a synergistic extractant ([Cyanex301]:[TOPO] molar concentration = 5:1), with the extraction conditions being: temperature 25°C, extraction time 20 min, phase ratio O:A = 1:5; after separation, a second raffinate and a nickel-containing organic phase are obtained, the nickel-containing organic phase containing 4.01 g / L Ni. The nickel-containing organic phase is first washed twice with 1M hydrochloric acid, and then stripped with 9M hydrochloric acid solution to obtain a stripping solution 2, with the stripping conditions being: temperature 25°C, time 20 min, phase ratio O:A = 3:1. An ammonium oxalate solution is added to the stripping solution 2, with the ammonium oxalate solution containing 0.5 mol / L ammonium oxalate and 0.5 mol / L sulfuric acid, and the pH value of the stripping solution 2 being adjusted to 1.5. The precipitation pH is 1.5, the temperature is 50°C, and the precipitation time is 1 h, and after filtration, a nickel oxalate solid is obtained. The nickel oxalate solid is dried and placed in a muffle furnace, sintered at 400°C for 1 h to obtain a nickel oxide sample.

[0073] In this embodiment, the recovery rate of molybdenum is 92.9%, and the purity of the molybdenum oxide product is 99.9%. The recovery rate of nickel is 93.1%, and the purity of the nickel oxide product is 99.0%.

[0074] Example 6

[0075] In combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application comprises the following steps:

[0076] Step 1, the waste nickel-molybdenum catalyst is washed three times with acetone to remove organic components on its surface, washed with water, dried at 80°C to remove residual water in the catalyst, and then crushed into 100 mesh powder and stored in a desiccator for subsequent use.

[0077] Step 2, a mixed acid leaching solution containing sulfuric acid and hydrogen peroxide is prepared, with the sulfuric acid concentration being 0.5 mol / L and the hydrogen peroxide concentration being 4 wt.%.

[0078] Step 3, the powder of step 1 is mixed with the mixed acid leaching solution of step 2 for leaching, the leaching conditions are: the reaction temperature is 25℃, the leaching time is 20 min, and the liquid-solid ratio is 0.5 g:10 mL. The leaching solution is obtained by filtration, and the composition of the leaching solution is shown in the following table:

[0079]

[0080] Step 4, the leaching solution of step 3 is adjusted to pH=0.5 with sulfuric acid, and two-stage countercurrent extraction is carried out using 0.6 mol / L P227, the extraction conditions are: the temperature is 25℃, the extraction time is 30 min, and the phase ratio O:A=1:3; after separation, the first raffinate and the loaded organic phase containing molybdenum are obtained, and the loaded organic phase containing molybdenum contains 15.70 g / L Mo. The loaded organic phase containing molybdenum is subjected to three-stage countercurrent stripping with 0.4 mol / L ammonium carbonate solution, the stripping conditions are: the temperature is 25℃, the time is 30 min, and the phase ratio O:A=3:1; after separation, the stripping solution 1 is obtained, and the stripping solution 1 contains 46.12 g / L Mo. The stripping solution 1 is concentrated by evaporation treatment to obtain ammonium molybdate, and the ammonium molybdate is sintered in a muffle furnace at 500℃ for 2h to obtain a molybdenum oxide product.

[0081] Step 5, after the first raffinate of step 4 is adjusted to pH=1 with an ammonia solution, three-stage countercurrent extraction is carried out using 0.45 mol / L synergistic extractant ([Cyanex301]:[TOPO] molar concentration=5:1), the extraction conditions are: the temperature is 25℃, the extraction time is 20 min, and the phase ratio O:A=1:5; after separation, the second raffinate and the organic phase containing nickel are obtained, and the organic phase containing nickel contains 4.01 g / L Ni. The organic phase containing nickel is first washed twice with 1M hydrochloric acid, and then stripped with 9M hydrochloric acid solution to obtain stripping solution 2, the stripping conditions are: the temperature is 25℃, the time is 20 min, and the phase ratio O:A=3:1. Ammonium oxalate solution is added to the stripping solution 2, wherein The precipitation pH is 1.5, the temperature is 50℃, and the precipitation time is 1h, and the nickel oxalate solid is obtained after filtration. The nickel oxalate solid is dried and placed in a muffle furnace, sintered at 400℃ for 1h to obtain a nickel oxide sample.

[0082] In this embodiment, the recovery rate of molybdenum is 93.2%, and the purity of the molybdenum oxide product is 99.7%. The recovery rate of nickel is 93.1%, and the purity of the nickel oxide product is 99.0%.

[0083] Example 7

[0084] In combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application comprises the following steps:

[0085] Step 1, the spent nickel-molybdenum catalyst was washed with acetone three times to remove the organic components on the surface, dried at 100°C after water washing to remove the residual water in the catalyst, then crushed into 200 mesh powder and stored in a desiccator for subsequent use.

[0086] Step 2, a mixed acid leaching solution containing sulfuric acid and hydrogen peroxide was prepared, wherein the concentration of sulfuric acid was 1.5 mol / L and the concentration of hydrogen peroxide was 8 wt.%.

[0087] Step 3, the powder of step 1 was mixed with the mixed acid leaching solution of step 2 for leaching, with the leaching conditions being: reaction temperature 35°C, leaching time 30 min, liquid-solid ratio 0.5 g:10 mL. The leaching solution was obtained by filtration, and the composition of the leaching solution is shown in the following table:

[0088]

[0089] Step 4, the leaching solution of step 3 was adjusted to pH=1 with sulfuric acid, and three-stage countercurrent extraction was performed using 1 mol / L P227, with the extraction conditions being: temperature 35°C, extraction time 30 min, phase ratio O:A=1:3; after separation, the first raffinate and the molybdenum-containing loaded organic phase were obtained, the molybdenum-containing loaded organic phase contained 16.37 g / L Mo. The molybdenum-containing loaded organic phase was washed with 0.1 mol / L sulfuric acid, and then three-stage countercurrent stripping was performed using 1 mol / L ammonium carbonate solution, with the stripping conditions being: temperature 35°C, time 30 min, phase ratio O:A=3:1; after separation, stripping solution 1 was obtained, which contained 48.12 g / L Mo. Ammonium molybdate was obtained by evaporation and concentration treatment of stripping solution 1, and molybdenum oxide product was obtained by sintering ammonium molybdate in a muffle furnace at 500°C for 2 h.

[0090] Step 5, after the first raffinate of step 4 was adjusted to pH=3 using an ammonia solution, two-stage countercurrent extraction was performed using 0.6 mol / L synergistic extractant ([Cyanex301]:[TOPO] molar concentration=5:1), with the extraction conditions being: temperature 35°C, extraction time 30 min, phase ratio O:A=1:5; after separation, the second raffinate and the nickel-containing organic phase were obtained, the nickel-containing organic phase contained 4.13 g / L Ni. The nickel-containing organic phase was first washed twice with 1M hydrochloric acid, and then stripped with 10M hydrochloric acid solution, to obtain stripping solution 2, with the stripping conditions being: temperature 35°C, time 20 min, phase ratio O:A=3:1. Ammonium oxalate solution was added to stripping solution 2, with The precipitation pH was 1.5, the temperature was 50°C, and the precipitation time was 1 h, and after filtration, nickel oxalate solid was obtained. The nickel oxalate solid was dried and placed in a muffle furnace, sintered at 500°C for 1 h to obtain a nickel oxide sample.

[0091] The recovery rate of molybdenum is 96.73%, and the purity of the molybdenum oxide product is 99.9%. The recovery rate of nickel is 94.99%, and the purity of the nickel oxide product is 99.1%.

[0092] Example 8

[0093] In combination Figure 1 The method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalyst according to the present application is specifically described as follows:

[0094] Step 1, the waste nickel-molybdenum catalyst is washed with acetone three times to remove the organic components on its surface, dried at 80°C after water washing to remove the residual water in the catalyst, then crushed into 50 mesh powder and stored in a desiccator for subsequent use.

[0095] Step 2, a mixed acid leaching solution containing sulfuric acid and hydrogen peroxide is prepared, wherein the concentration of sulfuric acid is 0.5 mol / L, and the concentration of hydrogen peroxide is 3 wt.%.

[0096] Step 3, the powder of step 1 is mixed with the mixed acid leaching solution of step 2 for leaching, and the leaching conditions are as follows: reaction temperature is 25°C, leaching time is 20 min, and liquid-solid ratio is 0.5 g:10 mL. The leaching solution is obtained by filtration, and the composition of the leaching solution is shown in the following table:

[0097]

[0098] Step 4, the leaching solution of step 3 is adjusted to pH=0 with sulfuric acid, and three-stage countercurrent extraction is carried out using 0.5 mol / L P227, and the extraction conditions are as follows: temperature is 25°C, extraction time is 30 min, and phase ratio O:A=1:3. After separation, the first raffinate and the molybdenum-containing loaded organic phase are obtained, and the molybdenum-containing loaded organic phase contains 15.61 g / L Mo. The molybdenum-containing loaded organic phase is washed with 0.1 mol / L sulfuric acid, and then three-stage countercurrent stripping is carried out using 0.4 mol / L ammonium carbonate solution, and the stripping conditions are as follows: temperature is 25°C, time is 10 min, and phase ratio O:A=3:1. After separation, the stripping solution 1 containing 46.15 g / L Mo is obtained. The stripping solution 1 is concentrated by evaporation treatment to obtain ammonium molybdate, and the ammonium molybdate is sintered in a muffle furnace at 500°C for 2 h to obtain a molybdenum oxide product.

[0099] Step 5, after the first raffinate of step 4 is adjusted to pH = 1 using an ammonia solution, the fourth stage countercurrent extraction is performed using 0.3 mol / L synergistic extractant ([Cyanex301]:[TOPO] = 5:1 in terms of molar concentration) under the following conditions: temperature 25℃, extraction time 10 min, phase ratio O:A = 1:5; the second raffinate and the nickel-containing organic phase are obtained by separation, and the nickel-containing organic phase contains 3.98 g / L Ni. The nickel-containing organic phase is first washed twice with 1M hydrochloric acid, and then is subjected to third stage countercurrent stripping with 8M hydrochloric acid solution to obtain a stripping solution 2, the stripping conditions are: temperature 25℃, time 10 min, phase ratio O:A = 3:1. Ammonium oxalate solution is added to the stripping solution 2, wherein The precipitation pH is 1.5, the temperature is 50℃, the precipitation time is 1h, and the nickel oxalate solid is obtained after filtration. The nickel oxalate solid is dried and placed in a muffle furnace, and sintered at 300℃ for 1h to obtain a nickel oxide sample.

[0100] In this embodiment, the recovery rate of molybdenum is 93.23%, and the purity of the molybdenum oxide product is 99.9%. The recovery rate of nickel is 92.33%, and the purity of the nickel oxide product is 99.2%.

[0101] In summary, the method for selectively recovering molybdenum and nickel from waste nickel-molybdenum catalysts of the present application pretreats the catalyst to remove the organic matter remaining on the surface thereof, and then crushes it into fine particles. The molybdenum and nickel in the catalyst are selectively leached by using a mixed acid leaching agent composed of sulfuric acid and hydrogen peroxide, and the leaching of aluminum is inhibited, thereby obtaining a sulfate solution containing molybdenum and nickel. Then, the molybdenum is selectively extracted by using an extractant P227, and after stripping with an alkaline reagent, a high-purity molybdenum enrichment solution is obtained, and a high-purity molybdenum oxide product is obtained by an evaporation crystallization sintering method. Then, the nickel is extracted from the raffinate by using a synergistic extractant containing Cyanex301 and TOPO, and after washing and hydrochloric acid stripping of the nickel-rich organic phase, a nickel enrichment solution can be obtained, and the enrichment multiple reaches 15 times. Then, a precipitant is added, and after precipitation and sintering, a high-purity nickel oxide product is obtained. This process can collect molybdenum and nickel at the same time through one-step leaching, and the recovery rates of molybdenum and nickel are both more than 93%, and the purity of the products is more than 99.0%. This process is simple to operate and low in energy consumption, and can fully recover valuable metals from waste catalysts, and is an economical and resource-friendly process, which can be widely applied in the field of catalyst recovery.

[0102] Obviously, the above embodiments are only examples for the purpose of clarity, and are not limiting on the embodiments. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. It is not necessary or possible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for selectively recovering molybdenum and nickel from spent nickel-molybdenum catalysts, characterized in that, Includes the following steps: Step 1: Wash the waste nickel-molybdenum catalyst with detergent to remove the organic components on its surface, dry it, pulverize it, sieve it and store it. Step 2: Prepare a mixed acidic leachate containing sulfuric acid and hydrogen peroxide; Step 3: Mix the powder from Step 1 with the mixed acidic leachate from Step 2 and leach, then filter to obtain the leachate. Step 4: Adjust the pH of the leachate from Step 3 to 0-1 with sulfuric acid, and perform single-stage or multi-stage countercurrent extraction using di(2-ethylhexyl)phosphonic acid solution as the extractant. Separate the liquid to obtain the first raffinate and the molybdenum-loaded organic phase. The molybdenum-loaded organic phase is back-extracted with an alkaline solution to obtain back-extract 1. Back-extract 1 is then concentrated by evaporation and sintered to obtain molybdenum oxide. Step 5: Adjust the pH of the first raffinate from Step 4 to 1-3 using ammonia solution, and then perform single-stage or multi-stage countercurrent extraction using the extractant bis(2,4,4-trimethylpentyl)dithiophosphonic acid. Separate the liquid to obtain the second raffinate and a nickel-containing organic phase. After back-extraction of the nickel-containing organic phase with hydrochloric acid solution, obtain back-extraction solution 2. Add a precipitant to back-extraction solution 2 to carry out precipitation and sintering reaction to obtain nickel oxide.

2. The method according to claim 1, characterized in that, In step 1, the detergent is acetone, carbon tetrachloride, or methane, the drying temperature is 80-100℃, and the particle size of the catalyst is pulverized between 50-200 mesh.

3. The method according to claim 1, characterized in that, In step 2, the sulfuric acid concentration in the mixed acidic leachate is 0.5-1.5 mol / L, and the hydrogen peroxide concentration is 3-8 wt.%.

4. The method according to claim 1, characterized in that, The leaching conditions in step 3 are: reaction temperature 25-35℃, leaching time 20-30min, and liquid-to-solid ratio of (0.1-1g):10mL.

5. The method according to claim 1, characterized in that, In step 4, the extractant is a 0.3-1 mol / L solution of di(2-ethylhexyl)phosphonic acid, and the extraction conditions are: the ratio of organic phase to aqueous phase is (0.2-5):1, the extraction temperature is 25-35℃, and the extraction time is 10-30 min.

6. The method according to claim 1, characterized in that, In step 4, the alkaline solution used for back-extraction is ammonia, sodium hydroxide, ammonium carbonate, or ammonium bicarbonate. The back-extraction conditions are: alkaline solution concentration of 0.4-1 mol / L, organic phase to aqueous phase ratio of (0.33-5):1, back-extraction temperature of 25-35℃, and back-extraction time of 10-30 min.

7. The method according to claim 1, characterized in that, In step 4, the sintering temperature is 500℃ and the time is 2 hours.

8. The method according to claim 1, characterized in that, In step 5, the extractant is a synergistic extractant composed of bis(2,4,4-trimethylpentyl)dithiophosphonic acid and tri-n-octylphosphine oxide. The extractant composition is as follows: the concentration of bis(2,4,4-trimethylpentyl)dithiophosphonic acid is 0.3-0.6 mol / L, and the concentration of tri-n-octylphosphine oxide is 0-0.3 mol / L. The extraction conditions are: the ratio of organic phase to aqueous phase is (0.14-3):1, the extraction temperature is 25-35℃, and the extraction time is 10-30 min.

9. The method according to claim 1, characterized in that, In step 5, the concentration of hydrochloric acid solution is 8-10 mol / L. The specific back-extraction conditions are: the ratio of organic phase to aqueous phase is (0.25-4):1, the back-extraction temperature is 25-35℃, and the back-extraction time is 10-20 min.

10. The method according to claim 1, characterized in that, In step 5, the precipitant added to the back-extraction solution 2 is ammonia, sodium hydroxide, or ammonium oxalate, and the sintering temperature is 300-500℃.

Images