Process for the preparation of monoatomic mercury catalysts from spent mercury catalysts and products thereof

Abstract

The application discloses a method for preparing a monatomic mercury catalyst by using a waste mercury catalyst as a raw material and a product thereof. The method comprises the following steps: mixing the waste mercury catalyst with a mercury chloride gasification aid, and then heating to 300-350 DEG C in an inert gas flow to perform catalytic gasification; and using a defective carbon carrier to adsorb and capture mercury chloride in tail gas of the catalytic gasification to obtain the monatomic mercury catalyst. The mercury chloride gasification aid comprises at least one of potassium nitrate, sodium nitrate, barium nitrate, zinc nitrate and cerium nitrate. The application adopts the method of catalytic gasification-defective capture to obtain the high-performance monatomic mercury catalyst in one step by using the waste mercury catalyst as a raw material. Meanwhile, the carbon carrier after catalytic mercury extraction is crushed, bonded and formed into a shape, and catalytic carbonization is performed to obtain a chlorinated defective carbon carrier, which is used as a carrier of the monatomic mercury catalyst again, so that the waste mercury catalyst is fully recycled and utilized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste mercury catalyst recycling and mercury catalyst preparation, and particularly relates to a method for preparing a single-atom mercury catalyst from waste mercury catalyst and a product thereof. BACKGROUND

[0002] Mercury catalyst is an important industrial catalyst for producing chloroethylene (acetylene chloroethylene) from acetylene and hydrogen chloride. The mercury catalyst is deactivated after being used for a certain period of time and is removed from the chloroethylene production device, becoming waste mercury catalyst. The waste mercury catalyst contains 2-3 wt.% of mercuric chloride. Since mercuric chloride is highly toxic, the random disposal of waste mercury catalyst can cause serious environmental pollution, and therefore, waste mercury catalyst is listed in the hazardous waste disposal list. At the same time, mercury is an important heavy metal resource, which plays an important role in catalysts, medicines and special devices. However, due to the increasing depletion of mercury resources in nature, it is particularly important to recycle the existing mercury resources. Therefore, efficient recycling of waste mercury catalyst can not only prevent mercury waste from harming the natural environment, but also recycle mercury resources and achieve great economic effects.

[0003] Currently, the technology for recycling waste mercury catalyst mainly focuses on how to extract mercury from waste mercury catalyst. The methods for recycling mercury mainly include liquid phase washing method, high-temperature distillation method and dry distillation method. The liquid phase washing method is to add NaCl, hydrochloric acid and other competitive adsorbents to desorb the mercuric chloride from the surface of activated carbon into the solution, and then use formaldehyde and other reducing agents to reduce the mercuric chloride into elemental mercury for recycling. Although this recycling process is simple to operate, the recovery rate of mercuric chloride is relatively low, only about 60%. The high-temperature distillation method is to first add NaOH, lime and other treatment agents to convert the mercuric chloride on the surface of activated carbon into mercuric oxide, and then heat to 700-800℃ to decompose the mercuric oxide into mercury vapor, and then condense to recover elemental mercury. In the process of extraction, inorganic salts such as lime are added to promote the volatilization of mercuric chloride. However, the addition of inorganic salts such as lime makes the ash content of the carbon carrier after mercury extraction exceed 50%, and even after acid washing and other treatments, high-performance activated carbon cannot be obtained. The dry distillation method is to directly heat the waste mercury catalyst at 500-600℃ in a nitrogen atmosphere to desorb the mercuric chloride on the surface of activated carbon into the gas phase, and then condense to recover the mercuric chloride. The use of mercuric chloride is to prepare a mercury catalyst by impregnation method, which is a complex process.

[0004] In summary, the current waste mercury catalyst recovery method, first add chemical reagent for processing, then washing or high temperature heat treatment to extract mercury element, and then prepare elemental mercury, and then prepare mercuric chloride, the whole recovery process is complex, environmental pollution. In addition, the current waste mercury catalyst treatment is mainly to refine the residual mercury as the main purpose, the carbon carrier recovered due to the crushing, collision and wear during the use of the catalyst, soaking or heat treatment during the catalyst recovery process, the mechanical strength is poor; and in order to improve the recovery rate of mercuric chloride, a large amount of chemical additives are added in the recovery process, so that the ash content of the recovered activated carbon is high and complex, the pore structure is poor, and the surface structure is seriously damaged. SUMMARY

[0005] In view of the above technical problems and the deficiencies in the art, the present application provides a method for preparing a single-atom mercury catalyst from waste mercury catalyst, which uses catalytic gasification to extract mercuric chloride and prepare a single-atom mercury catalyst. The process is simple, and the treatment of waste catalyst and the preparation of new catalyst are integrated. High-performance single-atom mercury catalyst and chlorinated defective carbon carrier are prepared at the same time. The recovered chlorinated defective carbon carrier is an excellent carrier for single-atom mercury catalyst to capture mercuric chloride, realizing the application of recycled carbon materials in the field, fully utilizing mercury resources and carbon resources, and achieving high-value utilization of waste mercury catalyst.

[0006] A method for preparing a single-atom mercury catalyst from waste mercury catalyst, comprising:

[0007] Mixing the waste mercury catalyst with a mercuric chloride gasification aid, and then heating to 300-350°C (preferably 300°C) in an inert gas stream to perform catalytic gasification, and using a defective carbon carrier to adsorb and capture mercuric chloride in the catalytic gasification tail gas to obtain a single-atom mercury catalyst; the heating rate is 30-100°C / min;

[0008] The mercuric chloride gasification aid includes at least one of potassium nitrate, sodium nitrate, barium nitrate, zinc nitrate, and cerium nitrate.

[0009] In some embodiments, the water content of the waste mercury catalyst is less than 3wt%.

[0010] The present application promotes the volatilization of mercuric chloride by using a mercuric chloride gasification aid. In some embodiments, the mass ratio of the mercuric chloride gasification aid to the waste mercury catalyst is 1-5:10, preferably 2:10.

[0011] The defective carbon carrier can include a chlorinated defective carbon carrier.

[0012] In some embodiments, the defective carbon carrier used in the present application comprises a chlorinated defective carbon carrier prepared from the waste mercury catalyst after catalytic gasification. The chlorinated defective carbon carrier has high adsorption strength and large adsorption capacity for chlorinated mercury, and the doping of the heteroatom chlorine improves the exchange process of chlorine in HCl and HgCl2 in the acetylene hydrochlorination reaction, thereby increasing the reaction rate and the reaction activity of the catalyst.

[0013] Further, the preparation method of the chlorinated defective carbon carrier can comprise: mixing, grinding and crushing the solid product of the catalytic gasification with an activating agent and a binder, and then performing kneading molding, drying and inert atmosphere carbonization to obtain the chlorinated defective carbon carrier.

[0014] In some embodiments, in the preparation method of the chlorinated defective carbon carrier, the activating agent can comprise at least one of melamine, dicyandiamide, urea and cyanuric acid. The above activating agent can promote the crosslinking of chloroethylene in the carbon deposition of the waste mercury catalyst and preliminary carbonization, and the residual chlorinated mercury gasification aid in the catalytic gasification process can become a defect inducer in the high-temperature carbonization process to form the chlorinated defective carbon carrier.

[0015] In some embodiments, in the preparation method of the chlorinated defective carbon carrier, the mass ratio of the activating agent to the waste mercury catalyst can be 1-5:10.

[0016] In the present application, the waste mercury catalyst carbon carrier after mercury extraction is finely ground and bonded and formed with a binder to form a granular chlorinated defective carbon carrier. In some embodiments, in the preparation method of the chlorinated defective carbon carrier, the binder can comprise at least one of gelatinized starch, humic acid salt and phenolic resin. The humic acid salt can be ammonium salt, etc.

[0017] In some embodiments, in the preparation method of the chlorinated defective carbon carrier, the mass ratio of the binder to the waste mercury catalyst can be 1-5:10.

[0018] In some embodiments, in the preparation method of the chlorinated defective carbon carrier, the carbonization temperature can be 800-900°C, preferably 850°C, and the time can be 2-4h, preferably 3h.

[0019] In the preparation method of the chlorinated defective carbon carrier, the inert atmosphere refers to a gas atmosphere that does not participate in the reaction, such as a nitrogen atmosphere and / or a noble gas atmosphere such as argon, etc.

[0020] In some embodiments, the mass ratio of the defective carbon carrier to the waste mercury catalyst can be 1:1-10, preferably 1:1.

[0021] In the present application, the inert gas flow refers to an inert gas flow that does not participate in the reaction, such as a nitrogen gas flow, a noble gas flow, etc.

[0022] In some embodiments, the flow rate of the inert gas stream can be 10-500 mL / min, such as 30 mL / min, 100 mL / min, etc.

[0023] In the present application, the rate of temperature increase is preferably 30-100℃ / min, such as 50℃ / min, 100℃ / min, etc.

[0024] In some embodiments, the time for catalytic gasification can be 30-480 min.

[0025] In the present application, the temperature for adsorbing and capturing mercury chloride is greater than 140℃, which is the volatilization temperature of mercury chloride powder, so that gaseous mercury chloride and the (chlorinated) defective carbon carrier form chemical adsorption, thereby forming a monolayer of dispersed mercury chloride on the surface of the (chlorinated) defective carbon carrier, and the saturated adsorption amount of mercury chloride of the (chlorinated) defective carbon carrier is much higher than the content of adsorbed and captured mercury chloride, which can ensure that mercury chloride has sufficient anchoring sites and does not agglomerate. In some embodiments, the temperature for adsorbing and capturing is greater than 140℃, and further can be no more than 250℃, and specifically can be 150-250℃, such as 150℃, 180℃, etc.

[0026] The present application also provides a monatomic mercury catalyst prepared by the method.

[0027] The existing waste mercury catalyst treatment technology has the problems of complex recovery process and inability of the carbon material after recovery treatment to be used for high-value utilization. The present application provides a method for preparing a monatomic mercury catalyst from waste mercury catalysts. The method uses waste mercury catalysts as raw materials and adopts a catalytic gasification-defect capturing method to obtain a high-performance monatomic mercury catalyst in one step. Meanwhile, the carbon carrier after catalytic mercury extraction is crushed and bonded into a shape and catalytically carbonized to obtain a chlorinated defective carbon carrier, which is used as a carrier for a monatomic mercury catalyst again, thereby realizing the full material recycling of waste mercury catalysts.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The present application uses waste mercury catalysts as raw materials to regenerate and prepare high-performance monatomic mercury catalysts in one step, and the process is simple, thereby realizing the integration of waste catalyst treatment and new catalyst preparation.

[0030] 2. The present application catalytically gasifies and captures mercury chloride in waste mercury catalysts to prepare high-performance monatomic mercury catalysts, and regenerates waste carbon carriers to obtain high-performance defective carbon carriers, thereby fully utilizing mercury resources and carbon resources and realizing the high-value utilization of waste mercury catalysts.

[0031] 3、The temperature (for example, 150-250℃) for adsorbing and capturing mercuric chloride by using the chlorination-defective activated carbon in the application is higher than the temperature (140℃) for acetylene hydrochlorination reaction, so that the monatomic mercury catalyst prepared has good thermal stability. DETAILED DESCRIPTION

[0032] The application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not used to limit the scope of the application.

[0033] Example 1

[0034] 10 kg of dried (water content less than 3wt%) waste mercury catalyst is mixed with 2 kg of gasification aid potassium nitrate, and then the mixed waste mercury catalyst is loaded into a gasification mercury extraction furnace, and 10 kg of chlorination-defective carbon carrier is loaded into a subsequent adsorption capturing furnace; then 30 mL / min of nitrogen is introduced into the gasification mercury extraction furnace, the gasification mercury extraction furnace is heated to 300℃ at a rate of 50℃ / min and kept constant for 2 h, and the adsorption capturing furnace is kept at 150℃ during this stage, then the gasification mercury extraction furnace is lowered to room temperature under nitrogen atmosphere, and the monatomic mercury catalyst prepared in the adsorption capturing furnace is taken out.

[0035] Then the carbon material after mercury extraction in the gasification mercury extraction furnace is taken out, mixed with 3 kg of activator melamine and 2 kg of binder ammonium humate, and ground, crushed and mixed in a grinder for 2 h, then the mixed carbon material is kneaded with 3 kg of water to form columnar particles with a diameter of 3-5 mm, and dried at 120℃ for 5 h. Then the dried carbon material precursor is carbonized in a carbonization furnace at a temperature of 850℃ in an inert atmosphere for 3 h to obtain a chlorination-defective carbon carrier material for preparing a monatomic mercury catalyst in the adsorption capturing furnace.

[0036] Example 2

[0037] The difference from Example 1 is only that the same amount of sodium nitrate is used instead of potassium nitrate, and the rest is the same.

[0038] Example 3

[0039] The difference from Example 1 is only that the amount of potassium nitrate is changed to 5 kg, and the rest is the same.

[0040] Example 4

[0041] The difference from Example 1 is only that the flow rate of nitrogen introduced into the gasification mercury extraction furnace is changed to 100 mL / min, and the rest is the same.

[0042] Example 5

[0043] Take 20 kg of dried waste mercury catalyst (moisture content less than 3 wt%) and mix with 4 kg of gasification aid potassium nitrate, then load the mixed waste mercury catalyst into the gasification mercury extraction furnace, load 10 kg of chlorinated defective carbon carrier into the subsequent adsorption capture furnace; then pass 30 mL / min of nitrogen into the gasification mercury extraction furnace, heat the gasification mercury extraction furnace to 300°C at a rate of 50°C / min and maintain the temperature for 2 h, the adsorption capture furnace is maintained at 150°C throughout this stage, then lower the gasification mercury extraction furnace to room temperature under nitrogen atmosphere, and take out the single-atom mercury catalyst prepared in the adsorption capture furnace.

[0044] Subsequently, take out the carbon material after mercury extraction in the gasification mercury extraction furnace, mix with 6 kg of activator melamine and 4 kg of binder ammonium humate, and grind, crush and mix in a grinder for 2 h, then add the mixed carbon material into 6 kg of water for kneading and extruding into columnar particles with a diameter of 3-5 mm, and dry at 120°C for 5 h. Then carbonize the dried carbon material precursor in a carbonization furnace at a temperature of 850°C in an inert atmosphere for 3 h to obtain a chlorinated defective carbon carrier material for preparing a single-atom mercury catalyst in the adsorption capture furnace.

[0045] Example 6

[0046] The difference from Example 1 is only that the final temperature of the gasification mercury extraction furnace is changed from 300°C to 350°C, and the rest are the same.

[0047] Example 7

[0048] The difference from Example 1 is only that the adsorption capture furnace temperature is changed from 150°C to 180°C, and the rest are the same.

[0049] Example 8

[0050] The difference from Example 1 is only that the heating rate of the gasification mercury extraction furnace is changed from 50°C / min to 100°C / min, and the rest are the same.

[0051] Example 9

[0052] Take 20 kg of dried waste mercury catalyst (moisture content less than 3 wt%) and mix with 4 kg of gasification aid potassium nitrate, then load the mixed waste mercury catalyst into the gasification mercury extraction furnace, load 10 kg of chlorinated defective carbon carrier into the subsequent adsorption capture furnace; then pass 30 mL / min of nitrogen into the gasification mercury extraction furnace, heat the gasification mercury extraction furnace to 300°C at a rate of 50°C / min and maintain the temperature for 2 h, the adsorption capture furnace is maintained at 150°C throughout this stage, then lower the gasification mercury extraction furnace to room temperature under nitrogen atmosphere, and take out the single-atom mercury catalyst prepared in the adsorption capture furnace.

[0053] The carbon material after mercury extraction in the gasification mercury extraction furnace was then taken out, mixed with 6 kg of the activating agent melamine and 4 kg of the binder ammonium humate in a grinder for grinding, crushing and mixing for 2 h, and then the mixed carbon material was added to 4 kg of water for kneading and extrusion into columnar particles with a diameter of 3-5 mm, and dried at 120°C for 5 h. Then the dried carbon material precursor was carbonized in a carbonization furnace in an inert atmosphere at a temperature of 850°C for 3 h to obtain a chlorinated defective carbon carrier material for adsorbing and capturing the single-atom mercury catalyst prepared in the furnace.

[0054] Example 10

[0055] The difference from Example 1 is only that the same mass of phenolic resin is used instead of ammonium humate, and the rest is the same.

[0056] Comparative Example 1

[0057] 10 kg of activated carbon was weighed, added to 30 L of a 30% by volume nitric acid solution, treated at 90°C for 5 h, then washed with deionized water, and then placed in a drying oven at 120°C for drying for 12 h; the dried activated carbon was then placed in a tube furnace for oxygen removal and defect creation treatment, under nitrogen, from room temperature to 800°C in 4 hours, held at 800°C for 10 min, naturally cooled to room temperature, and the sample was taken out, to obtain activated carbon rich in defects. 0.2 kg of mercuric chloride was accurately weighed, dissolved with 7 L of 0.1 mol / L hydrochloric acid solution, and after the mercuric chloride was completely dissolved, it was loaded onto the 10 kg of defective activated carbon by spraying, and impregnated at room temperature for 12 h. The above impregnated mercuric chloride catalyst was placed in a drying oven for drying, with a drying temperature set to 100°C, and dried for 8 h to remove the water in the catalyst, to obtain a single-atom mercury catalyst with a mercuric chloride content of 2%.

[0058] Comparative Example 2

[0059] Take 2 kg of coal quality carbon powder, take 0.5 kg of sucralose dissolved in 1.6 L of deionized water. After the sucralose is completely dissolved, gradually add it to the mixture of carbon powder and metal nitrate. After stirring and kneading, place it at room temperature for 10 h. The obtained sample is sent to the extruder for pressure extrusion molding to obtain columnar carbon with a diameter of 1.5 mm. Place it at room temperature for 10 h, then dry it at 110℃ for 8 h to remove excess water. The obtained sample is then sent to a rotary furnace, heated to 800℃ at a rate of 5℃ / min under nitrogen, and held at this temperature for 5 h for deep carbonization treatment. Naturally cool to room temperature to obtain chlorine-doped defective activated carbon. Accurately weigh 0.021 kg of mercury chloride and dissolve it in 0.8 L of 1 mol / L hydrochloric acid solution. Take 1 kg of the above chlorine-doped defective activated carbon and place it in the impregnation tank. After the mercury chloride is completely dissolved, add the mercury chloride impregnation solution to the impregnation tank and stir appropriately to ensure uniform impregnation. Impregnate at room temperature for 18 h, then dry at 110℃ for 12 h to obtain an ultra-low mercury catalyst with a mercury chloride mass fraction of 2 wt%.

[0060] Comparative Example 3

[0061] Take 10 kg of dried (moisture content less than 3 wt%) waste mercury catalyst and directly load it into the gasification mercury extraction furnace. Then load 10 kg of chlorine-doped defective carbon carrier into the subsequent adsorption capture furnace. Then pass 30 mL / min of nitrogen into the gasification mercury extraction furnace, heat the gasification mercury extraction furnace to 300℃ at a rate of 50℃ / min and hold for 2 h. The adsorption capture furnace is kept at 150℃ throughout this stage. Then cool the gasification mercury extraction furnace to room temperature under nitrogen atmosphere and remove the mercury catalyst prepared in the adsorption capture furnace.

[0062] Subsequently, take out the carbon material after mercury extraction from the gasification mercury extraction furnace, mix it with 3 kg of activator melamine and 2 kg of binder ammonium humate in a grinding machine for 2 h of grinding, crushing and mixing. Then add the mixed carbon material to 3 kg of water for kneading and extrusion molding into columnar particles with a diameter of 3-5 mm, and dry at 120℃ for 5 h. Then carbonize the dried carbon material precursor in a carbonization furnace at 850℃ under inert atmosphere for 3 h to obtain a chlorine-doped defective carbon carrier material for preparing single-atom mercury catalyst in the adsorption capture furnace.

[0063] Comparative Example 4

[0064] Weigh 10 kg of dried waste mercury catalyst (moisture content less than 3 wt%) and mix it with 2 kg of gasification aid potassium nitrate. Then, load the mixed waste mercury catalyst into the gasification mercury extraction furnace. Load 10 kg of untreated 3-5 mm columnar coal-based activated carbon into the subsequent adsorption capture furnace. Then, introduce nitrogen gas at 30 mL / min into the gasification mercury extraction furnace and heat it to 300℃ at 50℃ / min and keep it at that temperature for 2 hours. During this stage, the adsorption capture furnace is kept at 150℃. After that, the gasification mercury extraction furnace is cooled to room temperature in a nitrogen atmosphere, and the mercury catalyst prepared in the adsorption capture furnace is taken out.

[0065] Comparative Example 5

[0066] 10 kg of coal-based carbon powder, 3 kg of melamine activator, and 2 kg of ammonium humate binder were ground, crushed, and mixed in a grinder for 2 hours. Then, 3 kg of water was added to the mixed carbon material, which was kneaded and extruded into columnar particles with a diameter of 3-5 mm. These particles were then dried at 120°C for 5 hours. The dried carbon precursor was then carbonized in a carbonization furnace at 850°C for 3 hours in an inert atmosphere to obtain a carbon carrier material prepared from fresh coal-based carbon powder. This material was used to prepare single-atom mercury catalysts in an adsorption-capture furnace.

[0067] Then, 10 kg of dried waste mercury catalyst (moisture content less than 3 wt%) was weighed and mixed with 2 kg of gasification aid potassium nitrate. The mixed waste mercury catalyst was then loaded into the gasification mercury extraction furnace. 10 kg of carbon carrier material prepared from fresh coal char powder was loaded into the subsequent adsorption capture furnace. Nitrogen gas was then introduced into the gasification mercury extraction furnace at a rate of 30 mL / min. The gasification mercury extraction furnace was heated to 300 °C at a rate of 50 °C / min and kept at that temperature for 2 hours. During this stage, the adsorption capture furnace was kept at 150 °C. Afterward, the gasification mercury extraction furnace was cooled to room temperature under a nitrogen atmosphere, and the single-atom mercury catalyst prepared in the adsorption capture furnace was removed.

[0068] Comparative Example 6

[0069] The only difference from Example 1 is that the heating rate of the mercury gasification furnace is changed from 50°C / min to 5°C / min; all other aspects are the same.

[0070] The mercury catalysts prepared in the various examples and comparative examples were subjected to treatment at 140°C and an acetylene space velocity of 30 h⁻¹. -1 The catalytic performance was evaluated under the condition of V(HCl) / V(C2H2)=1.1:1, and the data obtained are listed in Table 1.

[0071] Table 1

[0072] Sample Conversion of acetylene (%) Selectivity to vinyl chloride (%) Example 1 99.6 >99 Example 2 96.5 >99 Example 3 98.1 >99 Example 4 99.8 >99 Example 5 99.4 >99 Example 6 98.4 >99 Example 7 99.3 >99 Example 8 99.7 >99 Example 9 97.6 >99 Example 10 99.6 >99 Comparative Example 1 93.2 >99 Comparative Example 2 95.3 >99 Comparative Example 3 30.6 >99 Comparative Example 4 43.2 >99 Comparative Example 5 95.8 >99 Comparative Example 6 94.3 >99

[0073] From the data of ethyne conversion rate of Comparative Example 1, Comparative Example 2 and Examples 1-10, it can be seen from Table 1 that the activity of the monatomic mercury catalyst prepared from the spent mercury catalyst in Examples 1-10 has reached or exceeded the activity of the monatomic catalyst prepared from fresh mercury chloride and activated carbon as the carbon carrier.

[0074] Comparing Comparative Example 1 and Example 2, Example 3, Example 4, Example 5, Example 6, Example 7 respectively, it can be found that changing the type and amount of gasification assistant, the flow rate of inert gas flow during gasification and mercury extraction, the ratio of spent mercury catalyst to defective activated carbon, the final temperature of the gasification and mercury extraction furnace and the adsorption and capture temperature will have certain influence on the ethyne conversion rate of the final mercury catalyst.

[0075] Comparing Comparative Example 1, Example 8 and Comparative Example 6, it can be found that changing the heating rate of the gasification and mercury extraction furnace will affect the ethyne conversion rate of the final mercury catalyst, and when the heating rate is lower than 30℃ / min, the ethyne conversion rate decreases significantly.

[0076] Comparing Comparative Example 1 and Example 9, Example 10 respectively, it can be found that changing the proportion of spent carbon and the binder during the preparation of the chlorinated defective activated carbon will have certain influence on the ethyne conversion rate of the final mercury catalyst.

[0077] Comparing Comparative Example 1-10 and Comparative Example 3, it can be found that without the gasification assistant during the mercury extraction process, the ethyne conversion rate of the catalyst decreases significantly, because without the gasification assistant, the mercury chloride in the spent mercury catalyst cannot be completely extracted.

[0078] Comparing Comparative Example 1-10 and Comparative Example 4, it can be found that without the chlorinated defective activated carbon during the adsorption and capture, but using ordinary coal-based activated carbon, the ethyne conversion rate of the catalyst decreases significantly, because the ordinary coal-based activated carbon does not have a large number of defects and cannot effectively adsorb and capture the mercury chloride that will be released.

[0079] Comparing Comparative Example 1-10 and Comparative Example 5, it can be found that without the spent catalyst activated carbon during the preparation of the chlorinated defective activated carbon, but using new coal powder, the ethyne conversion rate of the catalyst decreases to a certain extent, which shows that using the activated carbon material extracted from the spent mercury catalyst as the raw material for preparing the chlorinated defective activated carbon can improve the ethyne conversion rate of the catalyst, which may be that the assistant remaining in the activated carbon material extracted from the spent mercury catalyst promotes the activation of the carbon material.

[0080] In addition, it should be understood that, after reading the above description of the present application, those skilled in the art can make various modifications or modifications to the present application, and these equivalent forms also fall within the scope defined by the claims attached hereto.

Claims

1. A method for preparing a monoatomic mercury catalyst from a spent mercury catalyst, characterized by, The method comprises the following steps: The waste mercury catalyst is mixed with a mercury chloride gasification aid, and then heated to 300-350 DEG C in an inert gas stream to perform catalytic gasification, and the mercury chloride in the tail gas of the catalytic gasification is adsorbed and captured by a defective carbon carrier to obtain a monatomic mercury catalyst; the heating rate is 30-100 DEG C / min; the defective carbon carrier comprises a chlorinated defective carbon carrier prepared by recycling the waste mercury catalyst after catalytic gasification; The mercury chloride gasification aid comprises at least one of potassium nitrate, sodium nitrate, barium nitrate, zinc nitrate and cerium nitrate; The preparation method of the chlorinated defective carbon carrier comprises the following steps: the solid product of the catalytic gasification is mixed with an activating agent and a binder, ground and crushed, and then kneaded and formed, dried and carbonized in an inert atmosphere to obtain the chlorinated defective carbon carrier; The activating agent can promote the crosslinking of chloroethylene in the carbon deposition of the waste mercury catalyst and preliminary carbonization, and the residual mercury chloride gasification aid in the catalytic gasification process can become a defect inducer in the high-temperature carbonization process to form a chlorinated defective carbon carrier; the activating agent comprises at least one of melamine, dicyandiamide, urea and cyanuric acid; the mass ratio of the activating agent to the waste mercury catalyst is 1-5:10; the carbonization temperature is 800-900 DEG C, and the carbonization time is 2-4 h.

2. The method of claim 1, wherein, The water content of the waste mercury catalyst is less than 3wt%.

3. The method according to claim 1 or 2, characterized in that, The mass ratio of the mercury chloride gasification aid to the waste mercury catalyst is 1-5:

10.

4. The method of claim 3, wherein, The mass ratio of the mercury chloride gasification aid to the waste mercury catalyst is 2:

10.

5. The method of claim 1, wherein, In the preparation method of the chlorinated defective carbon carrier: The binder comprises at least one of gelatinized starch, humic acid salt and phenolic resin; The mass ratio of the binder to the waste mercury catalyst is 1-5:

10.

6. The method of claim 1, wherein, In the preparation method of the chlorinated defective carbon carrier, the carbonization temperature is 850 DEG C, and the carbonization time is 3 h.

7. The method of claim 1, 5 or 6, wherein, The mass ratio of the defective carbon carrier to the waste mercury catalyst is 1:1-10.

8. The method of claim 1, wherein, The flow rate of the inert gas stream is 10-500 mL / min.

9. The method of claim 1, wherein, The catalytic gasification time is 30-480 min.

10. The method of claim 1, wherein, The adsorption and capture temperature is 150-250 DEG C.

11. A monatomic mercury catalyst prepared by the method according to any one of claims 1-10.