Method for recovering precious metal in catalyst through microwave and microfluid opposite spraying combined enhanced vulcanization

Abstract

The invention discloses a method for recovering precious metals in a catalyst through microwave and microfluid opposite spraying combined enhanced vulcanization. The method comprises the following steps: (1) preparing a waste catalyst to be reacted and a Na2S solution in advance for later use; (2) mixing the prepared solutions, pumping the mixed solution into an injection needle cylinder, introducing the mixed solution into a micro-fluid opposite-spraying reactor through an injection pump, spraying, converging and mixing the mixed solution, and carrying out enhanced vulcanization reaction; (3) carrying out microwave treatment on the mixed and reacted solution by using a microwave generating device to enhance the settling performance; and (4) standing, observing and collecting the treated solution, filtering, collecting noble metal filter residues, and detecting the noble metal residual quantity of the filtrate. According to the method, the microwave technology and the micro-fluid opposite spraying technology cooperate with each other, the sulfuration precipitation and precious metal sulfide agglomeration sedimentation process is enhanced, precious metal Pt, Pd and Rh in the waste catalyst can be efficiently separated and recycled, and good economic benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of waste catalyst treatment and platinum group metals treatment and recycling technology, and in particular to a method for recovering precious metals from catalysts by microwave microfluidic combined spraying and enhanced sulfidation. Background Technology

[0002] In the field of industrial catalysis, precious metal catalysts are widely used due to their high efficiency and selectivity; however, long-term use leads to a decline in catalyst performance. Since spent catalysts typically contain precious metals such as Pt, Pd, and Rh, direct discharge not only causes economic losses but also has adverse environmental impacts. Therefore, precious metal recycling is currently a hot topic.

[0003] However, existing traditional sulfide precipitation treatment methods have drawbacks such as fine metal sulfide particles, uneven particle size distribution, poor sedimentation performance, and low recovery rates of precious metals Pt, Pd, and Rh, and they also cause certain environmental hazards.

[0004] Therefore, in order to solve the problems existing in the above-mentioned prior art, it is of great significance and application prospect to provide a method for efficiently recovering precious metals Pt, Pd and Rh, which is convenient for separation and more environmentally friendly. Summary of the Invention

[0005] In view of this, the present invention provides a method for the combined microwave and microfluidic spraying to enhance the recovery of precious metals from catalysts by sulfidation. By combining microfluidic spraying, microwave technology and sulfidation precipitation, the efficient recovery and separation of precious metals Pt, Pd and Rh from spent catalysts can be achieved, while also reducing the amount of sulfiding agent required.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts includes the following steps:

[0008] (1) Prepare the spent catalyst and Na2S solution to be reacted in advance for later use;

[0009] (2) Mix the prepared solutions, draw them into the syringe, and pass them into the microfluidic spray reactor through the injection pump. The mixture is sprayed, converged and mixed to produce an enhanced sulfidation reaction.

[0010] (3) The solution after the mixed reaction is microwave-treated using a microwave generator to enhance sedimentation performance;

[0011] (4) After standing, observe and collect the treated solution. After filtration, collect the precious metal residue and test the amount of precious metal residue in the filtrate.

[0012] Preferably, in step (1), the pH of the waste catalyst is adjusted to 1.0, and the concentration of the Na2S solution is 1-5 g / L.

[0013] Preferably, in step (2), the volume of the injection syringe is 150 ml, the volume ratio of the waste catalyst to the Na2S solution is 1:1, and the forward pushing speed of the injection pump is 50-70 mm / min.

[0014] Preferably, in step (2), the microfluidic jet reactor is designed and 3D printed.

[0015] Preferably, in step (2), the microfluidic spray reactor is provided with waste catalyst channels on both sides, the diameter of the waste catalyst channels is 600μm, the included angle is 30°, and the waste catalyst channels on both sides converge towards the center.

[0016] Preferably, two Na2S solution channels are provided in the middle of the two waste catalyst channels on both sides. The diameter of the Na2S solution channels is 400 μm and they are arranged vertically downward.

[0017] Preferably, in step (2), the enhanced sulfide precipitation reaction can improve the removal rate of precious metals Pt, Pd and Rh in the waste catalyst, so that their residual amounts are all less than 0.0005 g / L.

[0018] Preferably, in step (3), the microwave generator is designed and manufactured independently.

[0019] Preferably, in step (3), the microwave processing power is 200-500W and the set temperature is 30-70℃.

[0020] The above operations can promote the growth and aggregation of precious metal sulfide particles, enhance their settling properties, and facilitate subsequent separation and recycling.

[0021] The present invention achieves the following technical effects compared to the prior art:

[0022] (1) Microfluidic spraying technology: The microfluidic spraying technology introduced in this invention can greatly enhance the sulfidation precipitation reaction, shorten the reaction response time to the second level, and make the reaction more complete; and the introduction of this method can not only reduce the amount of sulfiding agent, but also improve the removal rate of precious metals Pt, Pd and Rh in waste catalysts, thereby improving economic benefits.

[0023] (2) Microwave crystallization technology: The microwave technology introduced in this invention can enhance the sedimentation performance of sulfide particles; after the mixed solution after the reaction is treated by microwave, the growth and aggregation process of precious metal sulfide particles is enhanced, giving them better sedimentation performance and facilitating subsequent separation and recycling.

[0024] (3) This invention combines microwave technology and microfluidic spraying technology to enhance the process of sulfide precipitation and precious metal sulfide agglomeration and sedimentation, which can efficiently separate and recover precious metals Pt, Pd and Rh from waste catalysts and has good economic benefits. Attached Figure Description

[0025] Figure 1 This is a diagram of the microwave-microfluidic spraying technology combined to enhance sulfide precipitation system of the present invention;

[0026] Figure 2 This is a comparison image of static placement before and after microwave irradiation treatment according to the present invention (left: without microwave treatment, right: with microwave treatment).

[0027] Figure 3 This is a comparison image of the filter before and after microwave irradiation treatment according to the present invention (left: without microwave treatment, right: with microwave treatment).

[0028] Figure 4 This is a diagram of the operating device of the present invention;

[0029] Figure 5 This is a diagram of the enhanced reaction apparatus of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention discloses a method for microwave-microfluidic combined spraying to enhance the recovery of noble metals from sulfidation catalysts, comprising the following steps:

[0032] (1) Prepare the spent catalyst and Na2S solution to be reacted in advance for later use;

[0033] (2) Mix the prepared solutions, draw them into the syringe, and pass them into the microfluidic spray reactor through the injection pump. The mixture is sprayed, converged and mixed to produce an enhanced sulfidation reaction.

[0034] (3) The solution after the mixed reaction is microwave-treated using a microwave generator to enhance sedimentation performance;

[0035] (4) After standing, observe and collect the treated solution. After filtration, collect the precious metal residue and test the amount of precious metal residue in the filtrate.

[0036] In step (1), the pH of the spent catalyst is adjusted to 1.0, and the concentration of the Na2S solution is 1-5 g / L.

[0037] In step (2), the volume of the syringe is 150 ml, the volume ratio of the waste catalyst to the Na2S solution is 1:1, and the forward pushing speed of the injection pump is 50-70 mm / min.

[0038] In step (2), the microfluidic jet reactor was designed and 3D printed independently.

[0039] In step (2), waste catalyst channels are provided on both sides of the microfluidic spray reactor. The diameter of the waste catalyst channels is 600 μm and the included angle is 30°. The waste catalyst channels on both sides converge towards the center.

[0040] Two Na2S solution channels are provided in the middle of the waste catalyst channels on both sides. The diameter of the Na2S solution channels is 400μm and they are set vertically downward.

[0041] In step (2), the enhanced sulfide precipitation reaction can improve the removal rate of precious metals Pt, Pd and Rh in the waste catalyst, so that their residual amounts are all less than 0.0005 g / L.

[0042] In step (3), the microwave generator is designed and manufactured independently.

[0043] In step (3), the microwave processing power is 200-500W and the set temperature is 30-70℃.

[0044] Example 1: Iron removal liquid sulfide precipitation

[0045] 1. Raw materials:

[0046] Waste catalyst (iron-free liquid, pH=0.55, precious metal content: Pt-0.0033g / L, Pd-0.0009 g / L, Rh-0.0132), sodium sulfide, sodium hydroxide.

[0047] 2. Pretreatment:

[0048] Add an appropriate amount of sodium hydroxide to the spent catalyst to adjust the pH to 1.0, and prepare a 5 g / L sodium sulfide solution for later use.

[0049] 3. Microfluidic jet reaction:

[0050] The prepared waste catalyst and Na2S solution were injected into 150ml syringes A and B respectively at a volume ratio of 1:1. The syringes were placed on the injection pump, and the injection pump syringes were connected to the microfluidic spray reactor through the pipeline. The injection pump was started and the retraction speed was set to 50-70mm / min. The two solutions were sprayed out from the microfluidic spray reactor and merged into one stream, and a sulfidation reaction occurred.

[0051] 4. Microwave treatment:

[0052] The solution after the mixed reaction flows through a pipe to a microwave generator, where it is treated by microwave irradiation in a microwave chamber. The microwave power is set to 200W and the temperature to 70℃. The mixed solution after microwave treatment flows directly into a collection device.

[0053] 5. Precipitation and separation of precious metals Pt, Pd, and Rh:

[0054] The collected mixed solution was allowed to stand, and the difference in the sedimentation process before and after microwave irradiation was observed. The mixed solution was filtered to obtain sulfide precipitates of precious metals Pt, Pd, and Rh, and the content of residual precious metals Pt, Pd, and Rh in the filtrate was detected.

[0055] 6. Results Analysis:

[0056] .

[0057] Example 2: Sulfation Precipitation of Displacement Solution

[0058] 1. Raw materials:

[0059] Used catalyst (replacement solution, pH=-0.94, precious metal content: Pt-0.0041g / L, Pd-0.0014 g / L, Rh-0.3867), sodium sulfide, sodium hydroxide.

[0060] 2. Pretreatment:

[0061] Take an appropriate amount of replacement fluid and prepare a 5-40 g / L sodium sulfide solution for later use.

[0062] 3. Microfluidic jet reaction:

[0063] The prepared waste catalyst and Na2S solution were injected into 60ml syringes A and B respectively at a volume ratio of 1:1. The syringes were placed on the injection pump, and the injection pump syringes were connected to the microfluidic spray reactor through the pipeline. The injection pump was started and the retraction speed was set to 80mm / min. The two solutions were sprayed out from the microfluidic spray reactor and merged into one stream, and a sulfidation reaction occurred.

[0064] 4. Microwave treatment:

[0065] The mixed solution flows through a pipe into a microwave generator, where it is irradiated with microwaves at a power of 200W and a temperature of 70℃. The microwave-treated solution then flows directly into a collection device.

[0066] 5. Precipitation and separation of precious metals Pt, Pd, and Rh:

[0067] The collected mixed solution was allowed to stand, and the difference in the sedimentation process before and after microwave irradiation was observed. The mixed solution was filtered to obtain sulfide precipitates of precious metals Pt, Pd, and Rh, and the content of residual precious metals Pt, Pd, and Rh in the filtrate was detected.

[0068] 6. Results Analysis:

[0069] .

[0070] Example 3: Neutralization liquid sulfide precipitation

[0071] 1. Raw materials:

[0072] Waste catalyst (neutralized solution, pH=-0.94, precious metal content: Pt-0.0041g / L, Pd-0.0014g / L, Rh-0.3867), sodium sulfide, sodium hydroxide.

[0073] 2. Pretreatment:

[0074] Take an appropriate amount of neutralizing solution and prepare a 5-40 g / L sodium sulfide solution for later use.

[0075] 3. Microfluidic jet reaction:

[0076] The prepared waste catalyst and Na2S solution were injected into 60ml syringes A and B respectively at a volume ratio of 1:1. The syringes were placed on the injection pump, and the injection pump syringes were connected to the microfluidic spray reactor through the pipeline. The injection pump was started and the retraction speed was set to 80mm / min. The two solutions were sprayed out from the microfluidic spray reactor and merged into one stream, and a sulfidation reaction occurred.

[0077] 4. Microwave treatment:

[0078] The mixed solution flows through a pipe into a microwave generator, where it is irradiated with microwaves at a power of 200W and a temperature of 70℃. The microwave-treated solution then flows directly into a collection device.

[0079] 5. Precipitation and separation of precious metals Pt, Pd, and Rh:

[0080] The collected mixed solution was allowed to stand, and the difference in the sedimentation process before and after microwave irradiation was observed. The mixed solution was filtered to obtain sulfide precipitates of precious metals Pt, Pd, and Rh, and the content of residual precious metals Pt, Pd, and Rh in the filtrate was detected.

[0081] 6. Results Analysis:

[0082] .

[0083] Example 4: Scale-up Experiment of Sulfide Precipitation in Concentrated Acidified Solution

[0084] 1. Raw materials:

[0085] Waste catalyst (concentrated acidified liquid, pH=-0.94, precious metal content: Pt-0.0071g / L, Pd-0.0034g / L, Rh-0.0345), sodium sulfide, sodium hydroxide.

[0086] 2. Pretreatment:

[0087] Take 5m 3 Heat the concentrated acidified solution to 70°C and prepare 1m 3 Prepare a 120 g / L sodium sulfide solution.

[0088] 3. Microfluidic jet reaction:

[0089] The prepared waste catalyst and Na2S solution are fed into a microfluidic spraying device with a flow rate of 7 L / min and a volume ratio of 5:1. The two solutions are sprayed out from the microfluidic spraying device and converge and mix into one stream, where a sulfidation reaction occurs.

[0090] 4. Precipitation and separation of precious metals Pt, Pd, and Rh:

[0091] The mixed solution was filtered to obtain sulfide precipitates of precious metals Pt, Pd, and Rh, and the content of residual precious metals Pt, Pd, and Rh in the filtrate was determined.

[0092] 5. Results Analysis:

[0093] The two sets of results are parallel samples.

[0094] .

[0095] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of precious metals from catalysts, characterized in that, Includes the following steps: (1) Prepare the spent catalyst and Na2S solution to be reacted in advance for later use; (2) Mix the prepared solutions, draw them into the syringe, and pass them into the microfluidic spray reactor through the injection pump. The mixture is sprayed, converged and mixed to produce an enhanced sulfidation reaction. (3) The solution after the mixed reaction is microwave-treated using a microwave generator to enhance sedimentation performance; (4) After standing, observe and collect the treated solution. After filtration, collect the precious metal residue and test the amount of precious metal residue in the filtrate.

2. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (1), the pH of the spent catalyst is adjusted to 1.0, and the concentration of the Na2S solution is 1-5 g / L.

3. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (2), the volume of the injection syringe is 150 ml, the volume ratio of the waste catalyst to the Na2S solution is 1:1, and the forward pushing speed of the injection pump is 50-70 mm / min.

4. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (2), the microfluidic jet reactor was designed and 3D printed independently.

5. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (2), waste catalyst channels are provided on both sides of the microfluidic spray reactor. The diameter of the waste catalyst channels is 600 μm and the included angle is 30°. The waste catalyst channels on both sides converge towards the center.

6. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 5, characterized in that, Two Na2S solution channels are provided in the middle of the two waste catalyst channels on both sides. The diameter of the Na2S solution channels is 400μm and they are set vertically downward.

7. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (2), the enhanced sulfide precipitation reaction can improve the removal rate of precious metals Pt, Pd and Rh in the waste catalyst, so that their residual amounts are all less than 0.0005 g / L.

8. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (3), the microwave generator is designed and manufactured independently.

9. The method for microwave-microfluidic combined spraying and enhanced sulfidation recovery of noble metals from catalysts according to claim 1, characterized in that, In step (3), the microwave processing power is 200-500W and the set temperature is 30-70℃.

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