A process and device for co-processing waste incineration fly ash in a steel dust zinc-extraction rotary kiln

Abstract

The application provides a process and device for treating waste incineration fly ash in a rotary kiln for zinc extraction from steel dust, which comprises the following steps: S1, heating treatment of the rotary kiln; S2, stirring and uniformly mixing the fly ash with an emulsifier, and then spraying the fly ash slurry into the kiln head of the rotary kiln for high-temperature roasting and detoxification through a screw pump, a Roots blower and a high-pressure sprayer in sequence; S3, mixing and granulating the steel dust and coke powder, and then inputting the mixture into the rotary kiln from the kiln tail for reaction; and S4, the volatile heavy metals in the fly ash and the steel dust enter a flue gas treatment system with flue gas to obtain a by-product secondary zinc oxide, and the non-volatile heavy metal melt solidifies and is poured into a water quenching tank from the kiln head of the rotary kiln to obtain kiln slag. The process is simple, the fly ash is sprayed into the rotary kiln from the kiln head after emulsification, the dioxin can be effectively removed by using the high-temperature section, and the by-product secondary zinc oxide and other heavy metal elements can be effectively recovered, so that the resource utilization of the steel dust and the waste incineration fly ash is realized, and the economic benefit can be improved.

Description

Technical Field

[0001] This invention relates to the field of waste treatment technology, and in particular to a process and apparatus for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas. Background Technology

[0002] With the rapid progress and development of my country's economy, environmental protection and sustainable development are receiving increasing attention. The treatment of pollutants such as municipal solid waste and industrial waste is gaining importance, and waste incineration technology is being applied more and more widely. During waste incineration, byproducts such as fly ash and low-ash are generated. Fly ash, in particular, contains dioxins and high concentrations of heavy metals, and is classified as hazardous waste, therefore requiring harmless treatment before final disposal. Currently, the main methods for disposing of waste incineration fly ash are cement / chelating agent solidification and stabilization landfill and cement kiln co-processing. Landfilling occupies a large amount of land, which is inconsistent with the principles of sustainable development. Cement kiln co-processing has limited capacity, with fly ash only added at a rate of 3% to 5% of cement clinker. There is an urgent need to find new ways to utilize fly ash resources. Furthermore, this treatment method cannot recover and reuse useful substances in the fly ash, greatly reducing its utilization value. Currently, when using rotary kilns to treat waste, dioxins may not be completely decomposed. A secondary combustion chamber needs to be installed at the tail end of the rotary kiln to further remove dioxins from the flue gas and achieve emission standards. This treatment method increases the cost of treatment to some extent. Summary of the Invention

[0003] In view of this, the present invention proposes a process and apparatus for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue dust.

[0004] The technical solution of this invention is implemented as follows:

[0005] A process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas, characterized by the following steps:

[0006] S1. Divide the interior of the rotary kiln into four sections, namely Section I, Section II, Section III, and Section IV, from the kiln tail to the kiln head. Heat the rotary kiln and set the temperature of each section as follows: Section I 300-700℃, Section II 700-1000℃, Section III 1000-1300℃, and Section IV 800-1000℃.

[0007] S2. The fly ash and emulsifier are mixed to obtain fly ash slurry. The fly ash slurry is then transported to the high-pressure sprayer through the screw pump and the Roots blower. The fly ash slurry is then sprayed into the kiln head of the rotary kiln through the high-temperature nozzle of the high-pressure sprayer for high-temperature calcination.

[0008] S3. After mixing steel dust and coke powder, the mixture is moistened and granulated to obtain a mixture. The mixture is then conveyed from the kiln tail to the rotary kiln for reaction.

[0009] S4. The fly ash and volatile heavy metals in the steel dust that have been roasted at high temperature in step S2 are recycled into the flue gas treatment system along with the flue gas to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high temperature and high pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0010] Furthermore, the emulsifier is a nonionic emulsifier with an HLB value of 17-18.

[0011] Furthermore, the emulsifier is one or a combination of two or more of MOA-23, TX-30, and TX-40.

[0012] Furthermore, the weight ratio of the fly ash slurry to the emulsifier is 50-80:1.

[0013] Furthermore, in step S2 above, the stirring temperature is 60-80℃, the stirring speed is 800-1200 r / min, and the stirring time is 60-80 min.

[0014] Furthermore, in step S2 above, the spraying speed of the high-pressure sprayer is 0.4 to 0.6 m / s; in step S3 above, the conveyor conveying speed is 1 to 3 m / s.

[0015] Furthermore, in step S3 above, the weight ratio of steel dust to coke powder is 2-4:1; and the moisture content of the mixture is 10-15%.

[0016] Furthermore, the temperatures corresponding to the four sections inside the rotary kiln are respectively set as follows: Zone I 350-700℃, Zone II 700-845℃, Zone III 1000-1050℃, and Zone IV 800-980℃.

[0017] Furthermore, the total length of the rotary kiln is 50-60m, the total firing time is 150-200min, the length of sections III and IV inside the rotary kiln is 20-25m, the temperature of section III is 1160-1240℃, the temperature of section IV is 900-980℃, and the fly ash residence time is 50-72min.

[0018] An apparatus for the co-processing of waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes a rotary kiln, a screw pump, a Roots blower, a high-pressure sprayer, a mixer, a conveyor, and a flue gas treatment system. The flue gas treatment system includes a settling chamber, a waste heat boiler, a surface cooler, a bag filter, and a tail gas desulfurization system. The screw pump is sequentially connected to the Roots blower and the high-pressure sprayer, and the nozzle of the high-pressure sprayer is connected to the kiln head of the rotary kiln. The mixer is connected to the kiln tail of the rotary kiln via a conveyor. One end of the settling chamber is connected to the kiln tail of the rotary kiln via a pipe, and the other end of the settling chamber is sequentially connected to the waste heat boiler, the surface cooler, the bag filter, and the tail gas desulfurization system via pipes. A chute is provided at the bottom of zone IV of the rotary kiln, and a high-temperature, high-pressure water gun is installed in the chute, with a water quenching tank below.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The process of this invention is simple. Fly ash can be directly sprayed from the kiln head into the high-temperature section of the kiln for high-temperature roasting and detoxification, promoting the efficient degradation of dioxins. The dioxin removal rate reaches 99.992-99.995%, which is comparable to the effect of removing dioxins in a secondary combustion chamber. This can reduce the step of setting up a secondary combustion chamber at the tail of the rotary kiln and save the construction cost of the secondary combustion chamber required in the existing co-processing methods.

[0021] 2. By recovering heavy metal elements from steel dust and waste incineration fly ash, the resource utilization of steel dust and waste incineration fly ash has been realized, and the recycling of kiln slag and zinc oxide brings certain economic benefits.

[0022] 3. The addition of emulsifiers is to improve the stability and flowability of fly ash during transportation, thereby more efficiently degrading and detoxifying harmful substances such as dioxins in fly ash and improving efficiency. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the present invention;

[0024] Figure 2 This is a schematic diagram of the apparatus for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas, according to the present invention.

[0025] Figure 3 This is a schematic diagram of the process apparatus for Comparative Example 2.

[0026] Icons: 1-Rotary kiln; 2-Screw pump; 3-Roots blower; 4-High-pressure sprayer; 5-Water quenching tank; 6-Mixer; 7-Conveyor; 8-Settling chamber; 9-Waste heat boiler; 10-Surface cooler; 11-Bag filter; 12-Tail gas desulfurization system. Detailed Implementation

[0027] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0028] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0029] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0030] See Figures 1 to 3 .

[0031] The following standards were followed when detecting dioxins in this embodiment and comparative examples:

[0032] (1) HJ77.3-2008 Determination of dioxins in solid waste by isotope dilution high-resolution gas chromatography-high-resolution mass spectrometry, used for dioxin sampling and detection in fly ash;

[0033] (2) HJ77.2-2008 Determination of dioxins in ambient air and exhaust gas by isotope dilution high-resolution gas chromatography-high-resolution mass spectrometry, used for sampling and detection of dioxins in flue gas.

[0034] Example 1

[0035] The apparatus used in this embodiment for the co-processing of waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes a rotary kiln 1, a screw pump 2, a Roots blower 3, a high-pressure sprayer 4, a mixer 6, a conveyor 7, and a flue gas treatment system. The flue gas treatment system includes a settling chamber 8, a waste heat boiler 9, a surface cooler 10, a bag filter 11, and a tail gas desulfurization system 12. The screw pump 2 is sequentially connected to the Roots blower 3 and the high-pressure sprayer 4, and the nozzle of the high-pressure sprayer 4 is connected to the kiln head of the rotary kiln 1. The mixer 6 is connected to the kiln tail of the rotary kiln 1 via the conveyor 7. One end of the settling chamber 8 is connected to the kiln tail of the rotary kiln 1 via a pipe, and the other end of the settling chamber 8 is sequentially connected to the waste heat boiler 9, the surface cooler 10, the bag filter 11, and the tail gas desulfurization system 12 via pipes. A chute is provided at the bottom of zone IV of the rotary kiln 1, and a high-temperature and high-pressure water gun is provided in the chute, with a water quenching tank 5 below it.

[0036] The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes the following steps:

[0037] S1. Divide the interior of the rotary kiln into four sections, from the kiln tail to the kiln head, namely Section I, Section II, Section III, and Section IV. Heat the rotary kiln and set the corresponding temperatures for each section as follows: Section I 350-700℃, Section II 700-845℃, Section III 1000-1050℃, and Section IV 800-980℃.

[0038] S2. Weigh fly ash and MOA-23 emulsifier at a weight ratio of 60:1, and stir for 60 minutes at a temperature of 60℃ and a rotation speed of 800 r / min to obtain fly ash slurry. Then, the fly ash slurry is transported to a high-pressure sprayer through a screw pump and a Roots blower. The fly ash slurry is sprayed into the kiln head of the rotary kiln through the high-temperature nozzle of the high-pressure sprayer at a spray speed of 0.4 to 0.6 m / s for high-temperature calcination treatment, so that the fly ash emulsion stays in the III and IV zones for 50 to 72 minutes.

[0039] S3. Steel dust and coke powder are mixed at a weight ratio of 2:1, granulated, and humidified to obtain a mixture with a moisture content of 10-12%. The mixture is then conveyed from the kiln tail to the rotary kiln at a speed of 1-3 m / s via a conveyor for reaction.

[0040] S4. The fly ash and volatile heavy metals in the steel dust that have undergone high-temperature roasting in step S2 are processed and recovered along with the flue gas into the flue gas treatment system to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high-temperature and high-pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0041] After processing using the process described in this embodiment, dioxins were measured in the treated flue gas collected from the tail end of the rotary kiln, and the dioxin removal rate reached 99.992%.

[0042] Example 2

[0043] The apparatus used in this embodiment for the co-processing of waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes a rotary kiln 1, a screw pump 2, a Roots blower 3, a high-pressure sprayer 4, a mixer 6, a conveyor 7, and a flue gas treatment system. The flue gas treatment system includes a settling chamber 8, a waste heat boiler 9, a surface cooler 10, a bag filter 11, and a tail gas desulfurization system 12. The screw pump 2 is sequentially connected to the Roots blower 3 and the high-pressure sprayer 4, and the nozzle of the high-pressure sprayer 4 is connected to the kiln head of the rotary kiln 1. The mixer 6 is connected to the kiln tail of the rotary kiln 1 via the conveyor 7. One end of the settling chamber 8 is connected to the kiln tail of the rotary kiln 1 via a pipe, and the other end of the settling chamber 8 is sequentially connected to the waste heat boiler 9, the surface cooler 10, the bag filter 11, and the tail gas desulfurization system 12 via pipes. A chute is provided at the bottom of zone IV of the rotary kiln 1, and a high-temperature and high-pressure water gun is provided in the chute, with a water quenching tank 5 below it.

[0044] The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes the following steps:

[0045] S1. Divide the interior of the rotary kiln into four sections, namely Section I, Section II, Section III, and Section IV, from the kiln tail to the kiln head. Heat the rotary kiln and set the temperature of each section as follows: Section I 300-700℃, Section II 700-1000℃, Section III 1000-1300℃, and Section IV 800-1000℃.

[0046] S2. Weigh fly ash and emulsifier at a weight ratio of 80:1, and stir for 80 minutes at a temperature of 60-80℃ and a rotation speed of 1200 r / min until well mixed. Then, transport the fly ash slurry to a high-pressure sprayer through a screw pump and a Roots blower. Spray the fly ash slurry into the kiln head of the rotary kiln at a spray speed of 0.4-0.6 m / s through the high-temperature nozzle of the high-pressure sprayer for high-temperature calcination treatment, so that the fly ash emulsion stays in the III and IV zones for 50-72 minutes. The emulsifier is composed of MOA-23 and TX-30 in a weight ratio of 1:1.

[0047] S3. Steel dust and coke powder are mixed in a weight ratio of 4:1, granulated, and humidified to obtain a mixture with a moisture content of 11-13%. The mixture is then conveyed from the kiln tail to the rotary kiln at a speed of 1-3 m / s via a conveyor for reaction.

[0048] S4. The fly ash and volatile heavy metals in the steel dust that have undergone high-temperature roasting in step S2 are processed and recovered along with the flue gas into the flue gas treatment system to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high-temperature and high-pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0049] After processing using the process described in this embodiment, dioxins were measured in the treated flue gas collected from the tail end of the rotary kiln, and the dioxin removal rate reached 99.994%.

[0050] Example 3

[0051] The system includes a rotary kiln 1, a screw pump 2, a Roots blower 3, a high-pressure sprayer 4, a mixer 6, a conveyor 7, and a flue gas treatment system. The flue gas treatment system includes a settling chamber 8, a waste heat boiler 9, a surface cooler 10, a bag filter 11, and a tail gas desulfurization system 12. The screw pump 2 is sequentially connected to the Roots blower 3 and the high-pressure sprayer 4, and the spray nozzle of the high-pressure sprayer 4 is connected to the kiln head of the rotary kiln 1. The mixer 6 is connected to the kiln tail of the rotary kiln 1 via the conveyor 7. One end of the settling chamber 8 is connected to the kiln tail of the rotary kiln 1 via a pipe, and the other end of the settling chamber 8 is sequentially connected to the waste heat boiler 9, the surface cooler 10, the bag filter 11, and the tail gas desulfurization system 12 via pipes. A chute is provided at the bottom of zone IV of the rotary kiln 1, and a high-temperature, high-pressure water gun is installed in the chute, with a water quenching tank 5 below it.

[0052] The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes the following steps:

[0053] S1. Divide the interior of the rotary kiln into four sections, namely Section I, Section II, Section III, and Section IV, from the kiln tail to the kiln head. Heat the rotary kiln and set the corresponding temperatures for each section as follows: Section I 300-700℃, Section II 700-1000℃, Section III 1160-1240℃, and Section IV 800-1000℃.

[0054] S2. Weigh fly ash and TX-30 emulsifier at a weight ratio of 70:1, and stir for 70 minutes at a temperature of 70℃ and a rotation speed of 900 r / min until well mixed. Then, transport the fly ash slurry to a high-pressure sprayer through a screw pump and a Roots blower. Spray the fly ash slurry into the kiln head of the rotary kiln at a spray speed of 0.4 to 0.6 m / s through the high-temperature nozzle of the high-pressure sprayer for high-temperature calcination treatment, so that the fly ash emulsion stays in the III and IV zones for 50 to 72 minutes.

[0055] S3. Steel dust and coke powder are mixed in a weight ratio of 3:1, granulated, and humidified to obtain a mixture with a moisture content of 12-13%. The mixture is then conveyed from the kiln tail to the rotary kiln at a speed of 1-3 m / s via a conveyor for reaction.

[0056] S4. The fly ash and volatile heavy metals in the steel dust that have undergone high-temperature roasting in step S2 are processed and recovered along with the flue gas into the flue gas treatment system to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high-temperature and high-pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0057] After processing using the process described in this embodiment, dioxins were measured in the treated flue gas collected from the tail end of the rotary kiln, and the dioxin removal rate reached 99.992%.

[0058] Example 4

[0059] The system includes a rotary kiln 1, a screw pump 2, a Roots blower 3, a high-pressure sprayer 4, a mixer 6, a conveyor 7, and a flue gas treatment system. The flue gas treatment system includes a settling chamber 8, a waste heat boiler 9, a surface cooler 10, a bag filter 11, and a tail gas desulfurization system 12. The screw pump 2 is sequentially connected to the Roots blower 3 and the high-pressure sprayer 4, and the spray nozzle of the high-pressure sprayer 4 is connected to the kiln head of the rotary kiln 1. The mixer 6 is connected to the kiln tail of the rotary kiln 1 via the conveyor 7. One end of the settling chamber 8 is connected to the kiln tail of the rotary kiln 1 via a pipe, and the other end of the settling chamber 8 is sequentially connected to the waste heat boiler 9, the surface cooler 10, the bag filter 11, and the tail gas desulfurization system 12 via pipes. A chute is provided at the bottom of zone IV of the rotary kiln 1, and a high-temperature, high-pressure water gun is installed in the chute, with a water quenching tank 5 below it.

[0060] The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes the following steps:

[0061] S1. Divide the interior of the rotary kiln into four sections, namely Section I, Section II, Section III, and Section IV, from the kiln tail to the kiln head. Heat the rotary kiln and set the temperature of each section as follows: Section I 350-700℃, Section II 700-1000℃, Section III 1160-1240℃, and Section IV 900-980℃.

[0062] S2. Weigh fly ash and emulsifier at a weight ratio of 75:1, and stir for 65 minutes at a temperature of 65℃ and a rotation speed of 1000 r / min until well mixed. Then, transport the fly ash slurry to a high-pressure sprayer through a screw pump and a Roots blower. Spray the fly ash slurry into the kiln head of the rotary kiln at a spray speed of 0.4-0.6 m / s through the high-temperature nozzle of the high-pressure sprayer for high-temperature calcination treatment, so that the fly ash emulsion stays in the III and IV zones for 50-72 minutes. The emulsifier is one or a combination of two or more of MOA-23, TX-30, and TX-40.

[0063] S3. Steel dust and coke powder are mixed at a weight ratio of 3.5:1, granulated, and humidified to obtain a mixture with a moisture content of 14-15%. The mixture is then conveyed from the kiln tail to the rotary kiln at a speed of 1-3 m / s via a conveyor for reaction.

[0064] S4. The fly ash and volatile heavy metals in the steel dust that have been roasted at high temperature in step S2 enter the settling system with the flue gas and settle. They are then treated and recovered by the flue gas treatment system to obtain secondary zinc oxide as a by-product. The molten solidified non-volatile heavy metals are flushed into the water quenching tank by high temperature and high pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0065] After processing using the process described in this embodiment, dioxins were measured in the treated flue gas collected from the tail end of the rotary kiln, and the dioxin removal rate reached 99.995%.

[0066] Comparative Example 1

[0067] No emulsifier was added during the processing of this comparative example, and the rest was the same as in Example 1.

[0068] The system includes a rotary kiln 1, a screw pump 2, a Roots blower 3, a high-pressure sprayer 4, a mixer 6, a conveyor 7, and a flue gas treatment system. The flue gas treatment system includes a settling chamber 8, a waste heat boiler 9, a surface cooler 10, a bag filter 11, and a tail gas desulfurization system 12. The screw pump 2 is sequentially connected to the Roots blower 3 and the high-pressure sprayer 4, and the spray nozzle of the high-pressure sprayer 4 is connected to the kiln head of the rotary kiln 1. The mixer 6 is connected to the kiln tail of the rotary kiln 1 via the conveyor 7. One end of the settling chamber 8 is connected to the kiln tail of the rotary kiln 1 via a pipe, and the other end of the settling chamber 8 is sequentially connected to the waste heat boiler 9, the surface cooler 10, the bag filter 11, and the tail gas desulfurization system 12 via pipes. A chute is provided at the bottom of zone IV of the rotary kiln 1, and a high-temperature, high-pressure water gun is installed in the chute, with a water quenching tank 5 below it.

[0069] The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes the following steps:

[0070] S1. Divide the interior of the rotary kiln into four sections, from the kiln tail to the kiln head, namely Section I, Section II, Section III, and Section IV. Heat the rotary kiln and set the corresponding temperatures for each section as follows: Section I 350-700℃, Section II 700-845℃, Section III 1000-1050℃, and Section IV 800-980℃.

[0071] S2. The fly ash slurry is sprayed into the kiln head of the rotary kiln through the high-temperature nozzle of the high-pressure sprayer at a spraying speed of 0.4 to 0.6 m / s for high-temperature calcination treatment, so that the fly ash emulsion stays in the III and IV zones for 50 to 72 minutes.

[0072] S3. Steel dust and coke powder are mixed at a weight ratio of 2:1, granulated, and humidified to obtain a mixture with a moisture content of 10-12%. The mixture is then conveyed from the kiln tail to the rotary kiln at a speed of 1-3 m / s via a conveyor for reaction.

[0073] S4. The fly ash and volatile heavy metals in the steel dust that have undergone high-temperature roasting in step S2 are processed and recovered along with the flue gas into the flue gas treatment system to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high-temperature and high-pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0074] After processing using the process described in this embodiment, dioxins were measured in the treated flue gas collected from the tail end of the rotary kiln, and the dioxin removal rate reached 95.892%.

[0075] Comparative Example 2

[0076] In this comparative example, fly ash emulsion is added to a rotary kiln from the kiln tail along with steel dust and coke powder for treatment, and the flue gas is discharged from the kiln head into the settling chamber. A schematic diagram of the device connection process in this comparative example is shown below. Figure 3 As shown.

[0077] The apparatus used in this comparative process for the co-processing of waste incineration fly ash in a rotary kiln for zinc extraction from steel flue dust.

[0078] The system includes a rotary kiln 1, a screw pump 2, a Roots blower 3, a high-pressure sprayer 4, a mixer 6, a conveyor 7, and a flue gas treatment system. The flue gas treatment system includes a settling chamber 8, a waste heat boiler 9, a surface cooler 10, a bag filter 11, and a tail gas desulfurization system 12. The screw pump 2 is sequentially connected to the Roots blower 3 and the high-pressure sprayer 4, and the spray nozzle of the high-pressure sprayer 4 is connected to the kiln tail of the rotary kiln 1. The mixer 6 is connected to the kiln tail of the rotary kiln 1 via the conveyor 7. One end of the settling chamber 8 is connected to the kiln head of the rotary kiln 1 via a pipe, and the other end of the settling chamber 8 is sequentially connected to the waste heat boiler 9, the surface cooler 10, the bag filter 11, and the tail gas desulfurization system 12 via pipes. A chute is provided at the bottom of zone IV of the rotary kiln 1, and a high-temperature, high-pressure water gun is installed in the chute, with a water quenching tank 5 below it.

[0079] The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas includes the following steps:

[0080] S1. Divide the interior of the rotary kiln into four sections, from the kiln tail to the kiln head, namely Section I, Section II, Section III, and Section IV. Heat the rotary kiln and set the corresponding temperatures for each section as follows: Section I 350-700℃, Section II 700-845℃, Section III 1000-1050℃, and Section IV 800-980℃.

[0081] S2. Weigh fly ash and MOA-23 emulsifier at a weight ratio of 60:1, and stir for 60 minutes at a temperature of 60℃ and a rotation speed of 800 r / min to obtain fly ash slurry. Then, the fly ash slurry is transported to a high-pressure sprayer through a screw pump and a Roots blower. The fly ash slurry is sprayed into the tail of the rotary kiln through the high-temperature nozzle of the high-pressure sprayer at a spray speed of 0.4 to 0.6 m / s for high-temperature calcination treatment, so that the fly ash emulsion stays in the III and IV zones for 50 to 72 minutes.

[0082] S3. Steel dust and coke powder are mixed at a weight ratio of 2:1, granulated, and humidified to obtain a mixture with a moisture content of 10-12%. The mixture is then conveyed from the kiln tail to the rotary kiln at a speed of 1-3 m / s via a conveyor for reaction.

[0083] S4. The fly ash and volatile heavy metals in the steel dust that have undergone high-temperature roasting in step S2 are processed and recovered along with the flue gas into the flue gas treatment system to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high-temperature and high-pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

[0084] After the process of this comparative example, the dioxins in the treated flue gas collected from the kiln head of the rotary kiln were measured, and the dioxin removal rate reached 97.758%.

[0085] The above results indicate that by treating fly ash using this process and apparatus, the emulsified fly ash is directly injected into the high-temperature zone from the kiln head, achieving complete dioxin decomposition. This eliminates the need for a secondary combustion chamber for subsequent processing. In contrast, fly ash treatment using kiln tail feeding involves the material first entering zones I and II (100-600℃). However, the decomposition temperature of dioxins is above 800℃, potentially leading to incomplete dioxin decomposition and necessitating a secondary combustion chamber. National regulations mandate the use of a secondary combustion chamber for calcining hazardous waste to ensure the flue gas remains at a sufficient temperature for a certain time, effectively removing dioxins and achieving emission standards. Furthermore, this invention co-treats fly ash with steel dust and sludge, with the fly ash blending ratio reaching over 40%, increasing the fly ash utilization rate.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas, characterized in that, Includes the following steps: S1. Divide the interior of the rotary kiln into four sections, from the kiln tail to the kiln head, namely Section I, Section II, Section III, and Section IV. Heat the rotary kiln and set the corresponding temperatures for each section as follows: Section I 300~700℃, Section II 700~1000℃, Section III 1000~1300℃, and Section IV 800~1000℃. S2. The fly ash and emulsifier are mixed to obtain fly ash slurry. The fly ash slurry is then transported to the high-pressure sprayer through the screw pump and the Roots blower. The fly ash slurry is then sprayed into the kiln head of the rotary kiln through the high-temperature nozzle of the high-pressure sprayer for high-temperature calcination. S3. After mixing steel dust and coke powder, the mixture is moistened and granulated to obtain a mixture. The mixture is then conveyed from the kiln tail to the rotary kiln for reaction. S4. The fly ash and volatile heavy metals in the steel dust that have been roasted at high temperature in step S2 are recycled into the flue gas treatment system along with the flue gas to obtain secondary zinc oxide as a by-product; the molten solidified material of non-volatile heavy metals is flushed into the water quenching tank by high temperature and high pressure water from the chute at the kiln head of the rotary kiln to obtain kiln slag.

2. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, The emulsifier is a nonionic emulsifier with an HLB value of 17-18.

3. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, The emulsifier is one or a combination of two or more of MOA-23, TX-30, and TX-40.

4. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, The weight ratio of fly ash slurry to emulsifier is 50~80:

1.

5. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, In step S2, the stirring temperature is 60~80℃, the stirring speed is 800~1200r / min, and the stirring time is 60~80min.

6. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, In step S2 above, the spraying speed of the high-pressure sprayer is 0.4~0.6m / s; in step S3 above, the conveyor conveying speed is 1~3m / s.

7. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, In step S3 above, the weight ratio of steel dust to coke powder is 2~4:1; the moisture content of the mixture is 10~15%.

8. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, The temperatures corresponding to the four sections inside the rotary kiln are set as follows: Zone I 350~700℃, Zone II 700~845℃, Zone III 1000~1050℃, and Zone IV 800~980℃.

9. The process for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue gas according to claim 1, characterized in that, The total length of the rotary kiln is 50-60m, the total firing time is 150-200min, the length of sections III and IV inside the rotary kiln is 20-25m, the temperature of section III is 1160-1240℃, the temperature of section IV is 900-980℃, and the fly ash residence time is 50-72min.

10. The apparatus for co-processing waste incineration fly ash in a rotary kiln for zinc extraction from steel flue dust according to any one of claims 1 to 9, characterized in that, The system includes a rotary kiln (1), a screw pump (2), a Roots blower (3), a high-pressure sprayer (4), a mixer (6), a conveyor (7), and a flue gas treatment system. The flue gas treatment system includes a settling chamber (8), a waste heat boiler (9), a surface cooler (10), a bag filter (11), and a tail gas desulfurization system (12). The screw pump (2) is connected in sequence to the Roots blower (3) and the high-pressure sprayer (4). The nozzle of the high-pressure sprayer (4) is connected to the kiln head of the rotary kiln (1). Connection; the mixer (6) is connected to the kiln tail of the rotary kiln (1) via the conveyor (7); one end of the settling chamber (8) is connected to the kiln tail of the rotary kiln (1) via a pipe, and the other end of the settling chamber (8) is connected to the waste heat boiler (9), surface cooler (10), bag filter (11), and tail gas desulfurization system (12) in sequence via pipes; a chute is provided at the bottom of zone IV of the rotary kiln (1), and a high-temperature and high-pressure water gun is provided in the chute and a water quenching pool (5) is provided below it.

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