A method for regenerating a spent zinc oxide desulfurizer

Abstract

The application belongs to the technical field of waste zinc oxide desulfurizer regeneration, and provides a waste zinc oxide desulfurizer regeneration method, which comprises the following steps: S1, crushing and screening the waste zinc oxide desulfurizer, adding the waste zinc oxide desulfurizer into a reaction kettle, and stirring after adding ammonia water; S2, passing in ammonia gas and continuing to stir; S3, adding a soluble iron salt and dropping hydrogen peroxide solution; S4, carbonizing by passing in carbon dioxide gas into the reaction kettle, adjusting the PH value of the solution, and then filtering to obtain filter cake and filtrate; S5, taking the filter cake to a sulfur melting kettle for recovery, taking the filtrate to an ammonia evaporation kettle, and performing cooling and filtering on the kettle liquid to obtain basic zinc carbonate filter cake; S6, drying, calcining and crushing the basic zinc carbonate filter cake to obtain active zinc oxide powder; and S7, uniformly kneading the active zinc oxide powder with a binder, a pore-forming agent, basic zinc carbonate and water, extruding into a strip, drying, calcining and obtaining a zinc oxide desulfurizer product. The method can realize green recovery of the zinc oxide desulfurizer, does not generate waste gas and waste liquid, and is environmentally friendly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of regeneration of waste zinc oxide desulfurizer, and particularly relates to a regeneration method of waste zinc oxide desulfurizer. BACKGROUND

[0002] Ecological environment protection is a focus problem today. Hydrogen sulfide is a toxic gas with extremely strong harm and is a main component of malodorous gas, which is derived from petroleum chemical industry, wastewater treatment, metallurgy, mineral and other industrial production. Hydrogen sulfide can deactivate catalysts in industrial production, corrode equipment, and can also cause poisoning to people, and even endanger life when the content is very high. At present, the main method for removing hydrogen sulfide gas is to use a desulfurizer. The zinc oxide desulfurizer is a desulfurizer with excellent desulfurization performance at normal temperature to medium-high temperature, and has the advantages of high desulfurization precision, simple use, high sulfur capacity, wide use temperature range and the like, and is widely used in industrial desulfurization systems, and is widely used in coal chemical industry, hydrogen production and synthetic ammonia and other chemical industries for desulfurization. It is the most widely used desulfurizer at present.

[0003] The active component of the zinc oxide desulfurizer is zinc oxide, and after the reaction of zinc oxide with hydrogen sulfide, most of the zinc oxide can be converted into zinc sulfide, so as to remove hydrogen sulfide in raw materials. When the sulfur content of the desulfurizer reaches saturation, the desulfurizer no longer has the function of desulfurization. The annual consumption of zinc oxide desulfurizer products in coal chemical industry and petroleum chemical industry can reach tens of thousands of tons. The zinc content in the waste desulfurizer is still more than 50%, and if the waste desulfurizer is recycled and utilized, the pollution of three wastes can be greatly reduced, the resource recycling can be realized, which is helpful for the construction and development of a resource-saving and environment-friendly society, and has high economic value and social benefits.

[0004] At present, there is little research on the regeneration of zinc oxide desulfurizer, and the dry process is mostly used for recycling of waste zinc oxide desulfurizer. The waste zinc oxide desulfurizer is first crushed, and then calcined in air to convert zinc sulfide into zinc oxide, and then impurities are removed through processes such as acidolysis, oxidation, slag removal, zinc powder replacement and acid radical ion precipitation to obtain a zinc salt. However, this method obtains a zinc salt instead of zinc oxide, and the recovery process has high energy consumption and generates a large amount of waste slag and waste gas containing sulfur dioxide.

[0005] Alternatively, a wet process is used. There are documents reporting that the waste zinc oxide desulfurizer is reacted with sulfuric acid in a closed container at room temperature to 220℃ to convert zinc in the waste desulfurizer into zinc sulfate and sulfur into elemental sulfur. However, acid-containing waste liquid is generated in this process, which is not conducive to the environment. Another wet process is to hydrothermally react the waste zinc oxide desulfurizer with pure water or ammonia water at 150-220℃ for 12-48 hours to convert zinc sulfide into zinc oxide. However, it can be known from the reaction thermodynamics that it is difficult to perform this method, and the hydrothermal reaction requires high temperature and high pressure, which is not conducive to industrialization due to high requirements for production equipment.

[0006] The treatment method of the rest waste zinc oxide desulfurizer also has: incineration, deep burying method, chemical treatment (including chemical inhibition, pickling, high pH value cleaning solvent, adopting lime neutralization, etc.), these treatment methods will bring high cost to enterprises and secondary pollution caused by sulfur dioxide gas emission. Since these treatment methods have many disadvantages and are not widely used, it is imminent to develop an environment-friendly and high-value-added waste zinc oxide desulfurizer recycling method. SUMMARY

[0007] In view of the deficiencies in the prior art, the present application provides a regeneration method of waste zinc oxide desulfurizer, which can realize green recovery of the desulfurizer, wherein ammonia is recycled, sulfur is recovered in the form of sulfur, no waste gas and waste liquid are produced, and it is environmentally friendly.

[0008] To achieve the above purpose, the following technical scheme is adopted: a regeneration method of waste zinc oxide desulfurizer, comprising the following steps:

[0009] S1, crushing the waste zinc oxide desulfurizer, sieving to obtain powder, adding the powder into a reaction kettle, then adding ammonia water and stirring;

[0010] S2, passing ammonia gas into the reaction kettle in S1 through a liquid ammonia storage tank, and continuing to stir; in the present application, the composition of the waste zinc oxide desulfurizer can be determined by analyzing the sample with an instrument to determine the content of zinc and sulfur.

[0011] The waste desulfurizer is a mixture containing metal sulfide and elemental sulfur, if the sulfur and metal elements can be separated, then sulfur can be obtained, environmental pollution can be reduced, and the inactivated zinc oxide can be regenerated and reused, turning waste into treasure.

[0012] The waste zinc oxide desulfurizer is treated with sulfuric acid solution, in the process of adding acid, a large amount of heat will be generated, and hydrogen sulfide will be released, which is dangerous and difficult to control, therefore, the present application selects to add ammonia water, which can avoid the release of hydrogen sulfide.

[0013] Based on the above purpose, the present application first adds ammonia water in the reaction kettle, so that the zinc oxide in the waste desulfurizer can react with the ammonia water to generate tetraammine zinc hydroxide. The reaction formula is as follows:

[0014] ZnO + 4NH3·H2O → Zn(NH3)4(OH)2 + 3H2O

[0015] S3, adding soluble iron salt into the reaction kettle in S2, stirring uniformly, then adding hydrogen peroxide solution dropwise;

[0016] Since zinc sulfide is poorly soluble in ammonia water, zinc sulfide is still present in the reaction solution in the reactor after ammonia gas is introduced. To recover this zinc sulfide, the present invention adds a certain amount of soluble iron salt, then drips hydrogen peroxide to dissolve the zinc sulfide in the reaction solution, oxidizing the sulfide ions to sulfur and precipitating it. At this point, the zinc sulfide is converted to zinc oxide, which then continues to react with ammonia water to generate tetraamminezinc hydroxide. The reaction formula is as follows:

[0017]

[0018] ZnO+4NH3·H2O→Zn(NH3)4(OH)2+3H2O

[0019] Among them, soluble iron salts act as catalysts to accelerate the oxidation of sulfide ions into sulfur and promote the conversion of zinc sulfide into zinc oxide.

[0020] After the hydrogen peroxide solution in S4 and S3 is added dropwise, carbon dioxide gas is introduced into the reactor for carbonization, and the pH value of the solution is adjusted to 9-10. The reaction is continued for a period of time, and then filtered to obtain a filter cake and a filtrate;

[0021] Carbon dioxide gas is introduced into the reactor to maintain the pH of the reaction solution at around 9-10. Then, part of the tetraammine zinc hydroxide reacts with carbon dioxide to convert into tetraammine zinc carbonate. The reaction formula is as follows:

[0022] Zn(NH3)4(OH)2+CO2→Zn(NH3)4CO3+H2O

[0023] At this time, the reaction solution still contains solid sulfur, and filtering can obtain a filter cake containing sulfur and a filtrate containing Zn.

[0024] S5, the filter cake obtained in S4 is taken to the sulfur melting kettle for recovery, the filtrate is taken to the ammonia still, and then the ammonia still is heated to deammoniate. After deammoniation, the still liquid is cooled and filtered to obtain a basic zinc carbonate filter cake;

[0025] The Zn-containing filtrate is heated in an ammonia still to remove ammonia. The reaction formula is as follows:

[0026]

[0027] When the filtrate is heated in the ammonia still, tetraamminezinc carbonate in the filtrate reacts with tetraamminezinc hydroxide to form a basic zinc carbonate precipitate and ammonia gas. The ammonia gas escapes the still along with the water vapor. After deamination is complete, the still liquid containing the basic zinc carbonate precipitate is cooled and filtered to obtain a basic zinc carbonate filter cake.

[0028] The steam evaporated from the ammonia evaporation kettle is a mixed gas containing ammonia, which can be cooled and then absorbed to obtain ammonia water, which can be used as a raw material for waste desulfurizer regeneration again to avoid waste gas generation. The filtrate obtained by filtering the kettle liquid can be used as incondensable gas absorption liquid in an absorption tower, so that the raw material can be fully reused.

[0029] S6, drying, calcining and crushing the basic zinc carbonate filter cake obtained in S5 to obtain active zinc oxide powder;

[0030] The active zinc oxide powder can be obtained by heating and decomposing the basic zinc carbonate at high temperature, and the reaction formula is as follows:

[0031]

[0032] S7, kneading the active zinc oxide powder obtained in S6 with a binder, a pore-forming agent, basic zinc carbonate and water uniformly, feeding the mixture into a strip extruder to form a strip-shaped object, drying and calcining the strip-shaped object to obtain a zinc oxide desulfurizer product.

[0033] The regenerated zinc oxide desulfurizer prepared by the method has the characteristics of green and high efficiency, and the overall zinc recovery rate is greater than 95%.

[0034] Based on the above method, the following improvements can be made in the present application:

[0035] Preferably, in S1, the sieving is sieving through a 200-mesh sieve, the molar ratio of zinc to ammonia in the reaction kettle is 1:4-6, and the mass fraction of ammonia water is 5-35%.

[0036] Preferably, in S1, the stirring temperature is 30-80℃, and the stirring time is 0.5-2h.

[0037] Preferably, in S2, after the ammonia gas is introduced, the concentration of ammonia in the reaction liquid in the reaction kettle is 5-35wt%.

[0038] Preferably, in S3, the soluble iron salt is a 1-10wt% ferrous chloride solution, after the ferrous chloride is added, the molar ratio of sulfur to iron in the reaction kettle is 100:0.1-1, the stirring temperature is 30-100℃, the mass fraction of hydrogen peroxide solution is 5-30%, and the molar ratio of hydrogen peroxide to sulfur in the powder is 1:1-2.

[0039] Preferably, in S4, the reaction temperature is 20-100℃, and the reaction time is 1-4h.

[0040] Preferably, in S5, the ammonia evaporation kettle is heated to a temperature of 100-150℃.

[0041] As preferred, in the S5, the filtrate obtained by filtering the kettle liquid is used as the absorption liquid for the absorption tower, and the steam volatilized from the ammonia evaporation kettle is condensed and absorbed in the absorption tower.

[0042] As preferred, in the S6, the drying temperature of the zinc carbonate hydroxide filter cake is 100-140℃, and the calcination temperature is 250-450℃.

[0043] As preferred, in the S7, the pore-forming agent is zinc carbonate hydroxide, the drying temperature of the shaped strip is 100-140℃, and the calcination temperature is 350-450℃.

[0044] Compared with the prior art, the present application has the following beneficial effects:

[0045] 1. The regeneration method of the waste zinc oxide desulfurizer provided by the present application uses a wet method to recover the zinc oxide desulfurizer, is green and efficient, has a zinc recovery efficiency of greater than 95%, recycles ammonia, recycles water, recovers sulfur in the form of sulfur, and overcomes the defect of a large amount of waste gas in dry recovery. The method does not produce waste gas and waste liquid, and is environmentally friendly.

[0046] 2. The regeneration method of the waste zinc oxide desulfurizer provided by the present application uses hydrogen peroxide as an oxidizing agent and an iron salt as a catalyst to rapidly dissolve the insoluble zinc sulfide, and converts S 2- in the zinc sulfide into sulfur, and the iron salt can accelerate the reaction speed and improve the yield.

[0047] 3. The regeneration method of the waste zinc oxide desulfurizer provided by the present application introduces carbon dioxide to carbonize, converts part of the tetraammine zinc hydroxide into tetraammine zinc carbonate, obtains the precipitate product zinc carbonate hydroxide after ammonia evaporation, and the zinc carbonate hydroxide can be used to prepare active zinc oxide. The zinc oxide desulfurizer prepared therefrom has better activity than the zinc oxide desulfurizer prepared from zinc hydroxide.

[0048] 4. The regeneration method of the waste zinc oxide desulfurizer provided by the present application uses zinc carbonate hydroxide as a pore-forming agent, avoids mixing of other useless components into the desulfurizer, improves the zinc oxide content of the desulfurizer, and increases the sulfur capacity of the desulfurizer. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The flowchart of the regeneration method of the waste zinc oxide desulfurizer provided by the embodiment of the present application is shown in the figure.

[0050] Figure 2 The process diagram of the regeneration method of the waste zinc oxide desulfurizer provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0051] The present application will be further described in detail below with reference to specific embodiments.

[0052] Example 1

[0053] A method for regenerating a spent zinc oxide desulfurizer, comprising the following steps:

[0054] S1, crushing the spent zinc oxide desulfurizer (zinc content of about 65.4%, sulfur content of about 11%) and sieving to obtain a powder with a particle size of less than 200 mesh, then adding 100 kg of the powder into a reaction kettle, and then adding 1360 kg of 5% (wt) ammonia water, and stirring at 30°C for 2 hours;

[0055] S2, passing ammonia gas 90 Nm 3 into the reaction kettle in S1 through a liquid ammonia storage tank to keep the ammonia concentration in the reaction liquid at about 5% (wt), and continuing to stir after the ammonia gas is passed in;

[0056] S3, raising the temperature of the reaction kettle in S2 to 30°C, adding 1% (wt) ferrous chloride solution into the reaction kettle according to a sulfur-iron molar ratio of 100:0.1, stirring uniformly, and then adding 76 kg of 5% (wt) hydrogen peroxide solution into the reaction kettle dropwise, and waiting until all the zinc sulfide in the kettle is completely reacted;

[0057] S4, passing carbon dioxide gas into the reaction kettle in S3 to adjust the PH value of the solution, so that the PH value of the solution in the reaction kettle is 9, and controlling the temperature of the reaction kettle at 100°C, and continuing to react for 1 hour, and then filtering to obtain a filter cake and a filtrate, and the filter cake is sulfur;

[0058] S5, taking the filter cake obtained in S4 to a sulfur melting kettle for recovery, and taking the filtrate to an ammonia evaporation kettle, heating the ammonia evaporation kettle to 100°C to evaporate the ammonia in the kettle liquid, passing the ammonia-containing steam through a cooler to obtain ammonia water, taking the non-condensable gas to an absorption tower for ammonia recovery, and taking the recovered ammonia water to the zinc oxide recovery process, and then cooling and filtering the kettle liquid to obtain basic zinc carbonate filter cake, and taking the filtrate to the absorption tower as an absorption liquid;

[0059] The absorption tower is a packed tower, and the absorption tower is divided into two sections, and water and the filtrate of the ammonia evaporation kettle are used as absorption agents, the upper section is a water absorption section, and the lower section is an ammonia evaporation kettle filtrate absorption section.

[0060] The ammonia-containing steam from the ammonia evaporation kettle is condensed by a cooler, and the gas-water mixture is taken to the lower part of the absorption tower, the gas is discharged from the top of the tower after absorption, and the kettle liquid is taken to an ammonia water storage tank.

[0061] The volume ratio of water to the filtrate of the ammonia evaporation kettle is 0.5:1.

[0062] S6, drying the basic zinc carbonate filter cake obtained in S5 at 100°C, and then calcining at 250°C, and then crushing and sieving to obtain active zinc oxide powder 78.2 kg, and the zinc oxide recovery rate is 96%;

[0063] S7, the active zinc oxide powder obtained in S6 is kneaded with a binder and basic zinc carbonate and water, and then sent to an extruder to form a strip, the strip is dried at 100°C, and then calcined at 350°C to obtain a zinc oxide desulfurizer product.

[0064] Example 2

[0065] A method for regenerating waste zinc oxide desulfurizer, comprising the following steps:

[0066] S1, the waste zinc oxide desulfurizer (zinc content of about 65.4%, sulfur content of about 11%) is crushed and sieved to obtain a powder with a particle size of less than 200 mesh, 100 kg of the powder is added to a reaction kettle, then 510 kg of 20% (wt) ammonia water is added, and stirring is carried out at 55°C for 1.3 hours;

[0067] S2, ammonia gas is introduced into the reaction kettle in S1 through a liquid ammonia storage tank for 40 Nm 3 , so that the concentration of ammonia in the reaction solution is maintained at about 10% (wt), and after the introduction of ammonia gas is completed, stirring is continued;

[0068] S3, the reaction kettle in S2 is heated to 65°C, a 5% (wt) ferrous chloride solution is added to the reaction kettle at a sulfur-iron molar ratio of 100:0.5, stirring is uniform, then 12.7 kg of 20% (wt) hydrogen peroxide solution is added dropwise to the reaction kettle, and the zinc sulfide in the kettle is fully reacted;

[0069] S4, carbon dioxide gas is introduced into the reaction kettle in S3 to adjust the PH value of the solution, so that the PH value of the solution in the reaction kettle is 9, and the temperature of the reaction kettle is controlled at 60°C, and the reaction is continued for 2 hours, then the filter cake and filtrate are obtained by filtration;

[0070] S5, the filter cake obtained in S4 is removed to a sulfur melting kettle for recovery, the filtrate is removed to an ammonia evaporation kettle, then the ammonia evaporation kettle is heated to 125°C, the ammonia in the kettle liquid is evaporated, the ammonia-containing steam is cooled to obtain ammonia water by a cooler, the non-condensable gas is removed to an absorption tower for ammonia recovery, the recovered ammonia water can be used in the zinc oxide recovery process, then the kettle liquid is cooled and filtered to obtain a basic zinc carbonate filter cake, and the filtrate is removed to an absorption tower as an absorption liquid;

[0071] The absorption tower is a packed tower, the absorption tower is divided into two sections, and water and the filtrate of the ammonia evaporation kettle are used as absorbents, the upper section is a water absorption section, and the lower section is an ammonia evaporation kettle filtrate absorption section.

[0072] The ammonia-containing steam from the ammonia evaporation kettle is condensed by a cooler, and the gas-water mixture is removed to the lower part of the absorption tower, the gas is discharged from the top of the tower after absorption, and the kettle liquid is removed to an ammonia water storage tank.

[0073] The volume ratio of water to the filtrate of the ammonia evaporation kettle is 1:1.

[0074] S6, drying the zinc hydroxycarbonate filter cake obtained in S5 at 120°C, then calcining at 350°C, and then crushing and sieving to obtain 79.5 kg of active zinc oxide powder, with a zinc oxide recovery rate of 97.7%; S7, kneading the active zinc oxide powder obtained in S6 with a binder and zinc hydroxycarbonate, adding water, and then feeding into an extruder to form a strip, drying the strip at 120°C, and then calcining at 400°C to obtain a zinc oxide desulfurizer product.

[0075] S7, kneading the active zinc oxide powder obtained in S6 with a binder and zinc hydroxycarbonate, adding water, and then feeding into an extruder to form a strip, drying the strip at 120°C, and then calcining at 400°C to obtain a zinc oxide desulfurizer product.

[0076] Example 3

[0077] A method for regenerating waste zinc oxide desulfurizer, comprising the following steps:

[0078] S1, crushing the waste zinc oxide desulfurizer (zinc content of about 65.4%, sulfur content of about 13%) and sieving to obtain powder with a particle size of less than 200 mesh, adding 100 kg of the powder into a reaction kettle, then adding 290 kg of 35% (wt) ammonia water, and stirring at 80°C for 0.5 hours;

[0079] S2, passing ammonia gas into the reaction kettle in S1 through a liquid ammonia storage tank at a flow rate of 100 Nm 3 , so that the concentration of ammonia in the reaction solution is maintained at about 35% (wt), and continuing to stir after the ammonia gas is passed in;

[0080] S3, raising the temperature of the reaction kettle in S2 to 100°C, adding 10% (wt) ferrous chloride solution with a sulfur-iron molar ratio of 100:1 into the reaction kettle, stirring uniformly, then adding 6.4 kg of 30% (wt) hydrogen peroxide solution dropwise into the reaction kettle, and waiting until all of the zinc sulfide in the kettle is completely reacted;

[0081] S4, passing carbon dioxide gas into the reaction kettle in S3 to adjust the PH value of the solution, so that the PH value of the solution in the reaction kettle is 10, and controlling the temperature of the reaction kettle at 20°C, and continuing to react for 4 hours, then filtering to obtain a filter cake and a filtrate;

[0082] S5, recovering the filter cake obtained in S4 in a sulfur melting kettle, removing the filtrate to an ammonia evaporation kettle, then heating the ammonia evaporation kettle to 150°C to evaporate the ammonia in the kettle liquid, passing the ammonia-containing steam through a cooler to obtain ammonia water, passing the non-condensable gas to an absorption tower to recover ammonia, using the recovered ammonia water in the zinc oxide recovery process, then cooling and filtering the kettle liquid to obtain a zinc hydroxycarbonate filter cake, and removing the filtrate to an absorption tower as an absorbent;

[0083] The absorption tower is a packed tower, and the absorption tower is divided into two sections, with clear water and filtrate from the ammonia evaporation kettle as the absorbents, the upper section being a clear water absorption section, and the lower section being a filtrate from the ammonia evaporation kettle absorption section.

[0084] The ammonia-containing steam from the ammonia distillation kettle is condensed by a cooler, and the gas-water mixture is sent to the lower part of the absorption tower. After absorption, the gas is discharged from the top of the tower, and the tower kettle liquid is sent to the ammonia water storage tank.

[0085] The volume ratio of clean water to filtrate from the ammonia distillation kettle is 1:1.

[0086] S6, the basic zinc carbonate filter cake obtained in S5 is dried at 140°C, then calcined at 450°C, and then crushed and sieved to obtain active zinc oxide powder 78.9 kg, with a zinc oxide recovery rate of 96.9%;

[0087] S7, the active zinc oxide powder obtained in S6 is kneaded uniformly with a binder, basic zinc carbonate and water, and then sent to an extruder to form a strip, the formed strip is dried at 140°C, and then calcined at 450°C to obtain a zinc oxide desulfurizer product.

[0088] Comparative Example 1

[0089] The hydrothermal method is used to recover zinc oxide without adding ferrous chloride solution, hydrogen peroxide to oxidize zinc sulfide, and without a carbonization process as a distinguishing condition.

[0090] S1, the waste zinc oxide desulfurizer (zinc content about 65.4%, sulfur content about 11%) is crushed and sieved to obtain a powder with a particle size less than 200 mesh, 10g of the powder is added to a hydrothermal reaction kettle, then 100g of 20%(wt) ammonia water is added, and the reaction is carried out at 200°C for 48 hours.

[0091] S2, the reaction kettle in S1 is cooled to 35°C, filtered and washed, and the filter residue and filtrate are collected.

[0092] S3, the filtrate obtained in S2 is distilled for ammonia at 100°C to obtain a zinc hydroxide precipitate.

[0093] S4, the zinc hydroxide precipitate obtained in S3 is filtered and washed, the filter cake is dried at 120°C, and calcined at 450°C to obtain 5.51g of zinc oxide powder, with a zinc oxide recovery rate of 67.6%.

[0094] S5, the zinc oxide powder obtained in S4 is kneaded uniformly with a binder, basic zinc carbonate and water, and then sent to an extruder to form a strip, the formed strip is dried at 120°C, and then calcined at 400°C to obtain a zinc oxide desulfurizer.

[0095] Experimental verification

[0096] The zinc oxide desulfurizer products prepared in Examples 1-3 and Comparative Example 1 are tested.

[0097] The regenerated zinc oxide desulfurizer is evaluated for desulfurization performance according to the method in industry standard HG / T2513-2014, and the specific results are shown in Table 1:

[0098] Table 1 - Results of sulfur capacity test of zinc oxide desulfurizer products prepared in Examples 1-3 and Comparative Example 1

[0099]

[0100]

[0101] From the results of Table 1, it can be seen that the regenerated zinc oxide desulfurizer products prepared in Examples 1-3 have high sulfur capacity, all greater than 20%, and can be used again. The sulfur capacity of the zinc oxide desulfurizer in the comparative example is significantly lower than that of Examples 1-3, because the desulfurization activity of zinc oxide prepared from zinc hydroxide is not as good as that of zinc oxide prepared from basic zinc carbonate.

[0102] From the comparative example, we see that the yield of zinc oxide recovered directly by the ammonia method is significantly lower than the present method, because when hydrogen peroxide is used as the oxidizing agent, ferrous chloride can act as a catalyst to make the poorly soluble zinc sulfide dissolve quickly, and the S in the zinc sulfide is converted to sulfur, increasing the yield of zinc oxide; at the same time, the active zinc oxide prepared by thermal decomposition of the basic zinc carbonate obtained by carbonization has good desulfurization activity. 2-

[0103] In the present application, the mechanisms, components and parts not described in the specific structure are existing structures in the prior art. They can be directly purchased from the market.

[0104] The above are only preferred embodiments of the present application, and are not used to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A method for regenerating a waste zinc oxide desulfurizer, characterized in that: The following steps are involved: S1. Grind the waste zinc oxide desulfurizer, sieve to obtain a powder, add the powder to a reactor, then add ammonia water and stir; S2, introduce ammonia gas into the reactor in S1 and continue stirring; S3, add soluble iron salt to the reactor in S2, stir evenly, and then add hydrogen peroxide solution dropwise; After the hydrogen peroxide solution in S4 and S3 is added dropwise, carbon dioxide gas is introduced into the reactor for carbonization, and the pH value of the solution is adjusted to 9-10. The reaction is continued for a period of time, and then filtered to obtain a filter cake and a filtrate; S5, the filter cake obtained in S4 is taken to the sulfur melting kettle for recovery, the filtrate is taken to the ammonia still, the ammonia still is heated to remove ammonia, and after the removal of ammonia, the still liquid is cooled and filtered to obtain a basic zinc carbonate filter cake; S6, drying, calcining, crushing and sieving the basic zinc carbonate filter cake obtained in S5 to obtain active zinc oxide powder; S7, after kneading the active zinc oxide powder obtained in S6 with a binder, a pore-forming agent, and water, the mixture is sent to an extruder to extrude and form a strip, and then the strip is dried and calcined to obtain a zinc oxide desulfurizer product; Wherein, in said S5, the filtrate obtained by filtering the kettle liquid is sent to the absorption tower as the absorption liquid, and the steam volatilized from the ammonia still is condensed and absorbed.

2. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, wherein: In the S1, the sieving is through a 200-mesh sieve, the mass fraction of the ammonia water is 5-35%, and the molar ratio of zinc to ammonia is 1:4-6.

3. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, characterized in that: In the step S1, the stirring temperature is 30-80° C., and the stirring time is 0.5-2 h.

4. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, wherein: In the step S2, after the ammonia gas is introduced, the concentration of ammonia in the reaction liquid in the reactor is 5-35% (wt).

5. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, characterized in that: In the S3, the soluble iron salt is a 1-10% (wt) ferrous chloride solution. After the ferrous chloride is added, the molar ratio of sulfur to iron in the reactor is 100:0.1-1, the stirring temperature is 30-100°C, the mass fraction of the hydrogen peroxide solution is 5-30%, and the molar ratio of hydrogen peroxide to sulfur in the powder is 1:1-2.

6. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, characterized in that: In the step S4, the reaction temperature is 20-100° C. and the reaction time is 1-4 hours.

7. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, characterized in that: In the step S5, the deammoniation temperature of the ammonia still is 100-150°C.

8. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, characterized in that: In the step S6, the drying temperature of the basic zinc carbonate filter cake is 100-140°C, and the roasting temperature is 250-450°C.

9. The method for regenerating a waste zinc oxide desulfurizer according to claim 1, characterized in that: In the step S7, the pore-forming agent is basic zinc carbonate, the drying temperature of the formed strips is 100-140°C, and the calcination temperature is 350-450°C.

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