Method for synergistic water washing of sintering machine head dust and blast furnace bag dust

Abstract

A kind of sintering machine head ash and blast furnace bag ash synergic washing method, according to the characteristics of blast furnace bag ash and sintering machine head ash, first blast furnace bag ash is enriched by fire method, then mixed with sintering machine head ash to make pulp, solve the problem of large water consumption and large scale in the process of high-salt solid waste treatment, at the same time, ammonia nitrogen in blast furnace bag ash and sintering machine head ash is recovered and utilized by using two methods, nitrate and sulfate in mother liquor are reasonably disposed, waste liquid is zero discharged, secondary pollution and rotary kiln corrosion are prevented.

Description

Technical Field

[0001] This invention relates to a synergistic water washing method, specifically a synergistic water washing method for sintering machine head ash and blast furnace bag ash, belonging to the field of sintering technology. Background Technology

[0002] Steel plants produce large amounts of high-salt solid waste, such as ash from the third and fourth sintering electric fields and blast furnace baghouse dust, which contain significant amounts of alkali and chloride metals. This waste cannot be directly returned to the system for disposal, as it could lead to equipment corrosion and kiln clogging. Currently, alkali and chloride metals are typically removed by water washing, and the wastewater is then treated and evaporated to recover crystalline salts.

[0003] Chinese patent CN101234766A, "Method for producing potassium chloride from sintering electrostatic precipitator ash in steel enterprises," reports a method for leaching sintering machine head ash using a compound solution of tap water and SDD inhibitor, achieving a potassium and sodium leaching rate of 95-99.5%. Chinese patent CN103435073A, "Method for producing potassium chloride from blast furnace gas ash in steel enterprises," reports the use of tap water to leach blast furnace gas ash, significantly reducing potassium and chloride content, and using the resulting leachate to prepare potassium chloride and sodium chloride.

[0004] In the treatment of high-salt solid waste in steel plants, evaporation and crystallization are commonly used. The process of evaporation and crystallization to produce salt is essentially a process of continuous solution concentration. Simultaneously, the leachate contains not only chloride salts but also sulfate and nitrate ions. These ions accumulate and circulate as the solution continues to concentrate. Traditionally, the mother liquor is added to the rotary kiln via spraying or batching, or, to avoid the mother liquor's influence on the crystallized salt, it is directly discharged. Sending the mother liquor into the rotary kiln via spraying or batching easily leads to kiln corrosion, while direct discharge causes secondary pollution.

[0005] Currently, sintering machine head ash and blast furnace baghouse ash are generally treated by separate water washing and resource recovery. Blast furnace baghouse ash typically contains 4-10% chloride, which is generally three times that of sintering machine head ash. Direct water washing for dechlorination requires large equipment and a large water volume, resulting in a large footprint and hindering water conservation. Both blast furnace baghouse ash and sintering machine head ash generated by steel plants are high-chlorine solid wastes that require water washing for dechlorination. Co-processing them is a better way to reduce investment and operational costs. However, existing methods simply mix blast furnace baghouse ash and sintering machine head ash without considering the characteristics of solid waste and material treatment.

[0006] In addition, the sintering machine head ash contains a lot of copper, and the water washing process will produce a copper-rich solution. The current practice is to directly precipitate the nitrogen, without effectively utilizing it, resulting in a waste of resources.

[0007] In summary, the current treatment of sintering machine head ash and blast furnace bag ash has problems such as large water consumption, ineffective utilization of copper ions in sintering machine head ash, and improper disposal of nitrate and sulfate ions in mother liquor. Summary of the Invention

[0008] To address the problems of excessive water consumption and inappropriate treatment methods for copper ions, nitrates, and sulfates in the current treatment of sintering machine head ash and blast furnace bag ash, this invention proposes a synergistic water washing method for sintering machine head ash and blast furnace bag ash. The blast furnace bag ash is treated by pyrometallurgical methods, and the resulting high-chloride dust after flue gas cooling is used in conjunction with kiln slag, which is then sorted by particle size and cooled. The resulting products are used for the treatment of sintering machine head ash. By treating blast furnace bag ash and sintering machine head ash separately according to their characteristics, the goal of zero wastewater discharge is achieved.

[0009] According to an embodiment of the present invention, a method for synergistic water washing of sintering machine head ash and blast furnace bag filter ash is provided.

[0010] A method for co-washing sintering machine head ash and blast furnace bag filter ash, the method comprising the following steps:

[0011] 1) Blast furnace bag ash is mixed with fuel and ammonia-containing water and pelletized to obtain green pellets. The green pellets are then roasted to obtain kiln slag and high-temperature flue gas.

[0012] 2) The high-temperature flue gas obtained in step 1) is cooled and dust removed to obtain high-chlorine dust and low-temperature flue gas;

[0013] 3) The kiln slag obtained in step 1) is screened to obtain large-particle kiln slag and small-particle kiln slag.

[0014] 4) After the small granular kiln slag is cooled with salt, a slag-containing mixture is obtained and / or fine granular kiln slag is separated from the small granular kiln slag, and the fine granular kiln slag is cooled with air to obtain cold slag.

[0015] 5) First, mix the high-chlorine dust obtained in step 2) with the sintering machine head ash, then add water and the slag-containing mixture obtained in step 4) to make a slurry. Perform hydrocyclone coarse separation on the slurry to obtain a mixture containing fine particles. Then, wash and filter the mixture containing fine particles to obtain a filter cake and a washing liquid.

[0016] 6) Add the cold residue obtained in step 4) to the washing liquid obtained in step 5) and react. After the reaction is completed, separate the copper-containing material and the reaction waste liquid.

[0017] 7) The reaction waste liquid obtained in step 6) is subjected to gravity and hardness removal treatment and then filtered to obtain filter residue and supernatant;

[0018] 8) First, adjust the supernatant obtained in step 7) to alkaline, then evaporate and separate the salts to obtain condensate containing ammonia nitrogen, potassium salt, sodium salt and mother liquor.

[0019] Preferably, the method further includes: 9) removing dust from the low-temperature flue gas obtained in step 2) to obtain secondary zinc oxide and clean flue gas.

[0020] Preferably, the method further includes: 10) the mother liquor obtained in step 8) is acidified and atomized and then recycled to step 4) to participate in salt cooling treatment.

[0021] Preferably, the mass ratio of blast furnace bag ash to fuel in step 1) is 50-100:1, more preferably 75-100:1.

[0022] Preferably, the moisture content of the blast furnace bag ash mixed with ammonia-containing water in step 1) is 10-14%, more preferably 11-13%.

[0023] Preferably, the ammonia nitrogen concentration in the ammonia-containing water in step 1) is 1000-3000 mg / L, more preferably 1500-2500 mg / L.

[0024] Preferably, the roasting temperature in step 1) is 1100–1500°C, more preferably 1100–1300°C.

[0025] Preferably, the roasting time in step 1) is 1.5 to 3 hours, more preferably 2 to 2.5 hours.

[0026] Preferably, the fuel in step 1) is one or both of pulverized coal and charcoal, with pulverized coal being the preferred choice.

[0027] Preferably, the cooling in step 2) is to cool the high-temperature flue gas to 150-200°C, more preferably 160-180°C.

[0028] Preferably, the cooling in step 2) is achieved by using a waste heat boiler and a surface cooler to cool the high-temperature flue gas.

[0029] Preferably, the dust removal process in step 2) involves using a bag filter to remove dust from the cooled high-temperature flue gas.

[0030] Preferably, the particle size of the large kiln slag particles in step 3) is greater than 20 mm, and more preferably 20 mm to 40 mm.

[0031] Preferably, the particle size of the small kiln slag particles in step 3) is less than 20 mm, and more preferably 3 to 20 mm.

[0032] Preferably, the fine kiln slag in step 4) has a particle size of less than 3 mm, and more preferably 0 to 3 mm.

[0033] Preferably, step 3) further includes: 31) the large granular kiln slag obtained in step 3) is cooled with water and then sent to the sintering process.

[0034] Preferably, the mass ratio of sintering machine head ash to high-chlorine dust in step 5) is 7-10:1, more preferably 8-9:1.

[0035] Preferably, the high-chlorine dust, sintering machine head ash, water and slag-containing mixture obtained in step 5) are used to obtain a slurry. The slurry is then subjected to coarse separation by cyclone separation to obtain a mixture containing fine particles. The mixture containing fine particles is then washed with water. During the mixing process, the solid-liquid ratio of the slurry is 0.25-0.5 kg / L, preferably 0.28-0.4 kg / L.

[0036] Preferably, the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is 2-6 kg / L, and more preferably 3-5 kg / L.

[0037] Preferably, the swirling process described in step 5) uses a swirling separator.

[0038] Preferably, step 5) further includes: 51) sending the obtained filter cake to the sintering process.

[0039] Preferably, the solid-liquid ratio of the cold slag and the washing liquid in step 6) is 1-5 g / L, and more preferably 2-3 g / L.

[0040] Preferably, the reaction time in step 6) is 0.5 to 1 hour, more preferably 0.6 to 0.8 hours.

[0041] Preferably, the degravation and hardening in step 7) involves adding a degravation agent and a hardening agent to the reaction waste liquid.

[0042] Preferably, the degravation agent is sodium sulfide or a degravation precipitator, and the amount added is 0.8-8 g / L, preferably 1-5 g / L.

[0043] Preferably, the hardening agent is sodium carbonate, and the amount added is 2-15 g / L, more preferably 3-10 g / L.

[0044] Preferably, the reaction time for weight removal and hardening removal is 0.5 to 2 hours, and more preferably 0.8 to 1.5 hours.

[0045] Preferably, step 8) involves adjusting the supernatant to alkalinity by using an alkaline solution to adjust the pH of the supernatant to 11-13; preferably, the alkaline solution is one or both of sodium hydroxide and potassium hydroxide.

[0046] Preferably, the salt separation by evaporation in step 8) is a multi-stage countercurrent evaporation, preferably a three-stage countercurrent evaporation.

[0047] Preferably, step 8) further includes: 81) adding the ammonia-containing nitrogen wastewater obtained in step 8) as ammonia-containing wastewater to the mixing and pelletizing process in step 1) and / or adding it as ash washing water to the washing process of the mixed liquid containing fine particles in step 5).

[0048] Preferably, the acidification in step 10) involves adjusting the pH of the mother liquor to 2-7 using concentrated sulfuric acid, more preferably 3-6.

[0049] Preferably, step 1) specifically involves: mixing blast furnace bag ash and fuel at a mass ratio of 50–100:1 (preferably 75–100:1); after mixing, adding ammonia-containing water with an ammonia nitrogen content of 1000–3000 mg / L (preferably 1500–2500 mg / L) at a moisture content of 10–14% (preferably 11–13%) to form pellets; sending the resulting green pellets into a rotary kiln; and calcining them in the rotary kiln at 1100–1500℃ (preferably 1100–1300℃) for 1.5–3 hours (preferably 2–2.5 hours) to obtain kiln slag and high-temperature flue gas.

[0050] Preferably, step 2) specifically involves: introducing the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler to cool it down to 150-200°C (preferably 160-180°C), and then separating the flue gas through a bag filter to obtain high-chlorine dust and low-temperature flue gas.

[0051] Preferably, step 3) specifically involves separating the kiln slag obtained in step 1) according to the particle size of the kiln slag, to obtain large-particle kiln slag with a particle size greater than or equal to 20 mm and small-particle kiln slag with a particle size less than 20 mm; wherein, the large-particle kiln slag is sent to the sintering process after being water-cooled.

[0052] Preferably, step 4) specifically involves: separating fine slag particles with a particle size of less than 3 mm from small slag particles with a particle size of less than 20 mm, sending the small slag particles with a particle size of 3 to 20 mm to salt cooling, obtaining a slag-containing mixture after salt cooling, and sending the fine slag particles with a particle size of less than 3 mm to air cooling, obtaining cold slag after air cooling.

[0053] Preferably, step 5) specifically involves: mixing the sintering machine head ash with the high-chlorine dust obtained in step 2) at a mass ratio of 7-10:1 (preferably 8-9:1), and adding the slag-containing mixture obtained in step 4) at a solid-liquid ratio of 0.25-0.5 kg / L (preferably 0.28-0.4 kg / L) to prepare a slurry. The slurry is then subjected to coarse separation to obtain a mixture containing fine particles. The mixture containing fine particles is then washed with water, and the water used for washing the ash is partly ammonia-nitrogen-containing condensate. The mixture is then filtered to obtain a filter cake and a washing liquid. The filter cake is then sent to the sintering process.

[0054] Preferably, step 6) specifically involves adding the cold slag obtained in step 4) to the washing liquid obtained in step 5) at a solid-liquid ratio of 1-5 g / L (preferably 2-3 g / L), reacting for 0.5-1 h (preferably 0.6-0.8 h), and then filtering to obtain copper-containing material and reaction waste liquid.

[0055] Preferably, step 7) specifically involves adding a weight removal agent and a hardening removal agent to the reaction waste liquid obtained in step 6), stirring and reacting for 0.5 to 2 hours (preferably 0.8 to 1.5 hours), and then filtering to obtain filter residue and supernatant; wherein the weight removal agent is sodium sulfide or a weight catching agent, and the amount added is 0.8 to 8 g / L (preferably 1 to 5 g / L); the hardening removal agent is sodium carbonate, and the amount added is 2 to 15 g / L (preferably 3 to 10 g / L).

[0056] Preferably, step 8) specifically involves: adjusting the pH of the supernatant obtained in step 7) to 11-13 using one or both of sodium hydroxide and potassium hydroxide; then introducing the pH-adjusted supernatant into an evaporation system; the supernatant sequentially passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor to obtain ammonia-nitrogen-containing wastewater condensate, potassium salt, sodium salt, and mother liquor; the ammonia-nitrogen-containing wastewater condensate is then used in the mixing and pelletizing process described in step 1); wherein the temperature in the triple-effect reactor is 20-60℃ (preferably 30-50℃), and the vacuum degree is -150 to -5. The temperature of the second-effect evaporation is 40-90℃ (preferably 50-80℃), and the vacuum degree is -100-30kPa (preferably -70-40kPa). The temperature of the first-effect evaporation is 70-105℃ (preferably 80-100℃), and the vacuum degree is -50-10kPa (preferably -40-15kPa). The condensate from the steam outlet of the third-effect reactor is collected, which is the ammonia-nitrogen-containing condensate. Preferably, the flow direction of the supernatant is opposite to the flow direction of the steam.

[0057] Preferably, step 9) specifically involves sending the low-temperature flue gas obtained in step 2) into a bag filter, and after dust removal, obtaining secondary zinc oxide and clean flue gas.

[0058] Preferably, step 10) specifically involves adjusting the pH of the mother liquor obtained in step 8) to 2-7 (preferably 3-6) with concentrated sulfuric acid, and then atomizing it before adding it as a high-salt cooling liquid to the salt cooling process described in step 4).

[0059] In this invention, blast furnace bag ash is first enriched using a pyrometallurgical process. The blast furnace bag ash is mixed with pulverized coal and ammonia-containing water to form pellets, which are then roasted. Chlorides, zinc, lead, and other substances in the blast furnace bag ash decompose and volatilize into the flue gas, while iron remains in the slag phase, resulting in kiln slag and high-temperature flue gas with high chlorine content. Then, by gradient cooling of the high-temperature flue gas, lead and chlorine are enriched in the dust. Testing shows that the high-chlorine dust obtained after pyrometallurgical enrichment has a chlorine content of 20-30%, while its mass is only 3-10% of the mass of the blast furnace bag ash. Washing the enriched high-chlorine dust with water significantly reduces the scale and volume of the washing process. Furthermore, comparisons show that washing the high-chlorine dust with water yields better water quality than directly washing the blast furnace bag ash; the concentration of ammonia nitrogen in the wastewater is reduced by 10 times, and the concentration of iron is reduced by 800 times.

[0060] In this invention, based on the characteristics of the kiln slag and the requirements for subsequent utilization, the obtained kiln slag undergoes staged cooling. Large-particle kiln slag is sent to a water-cooling process; fine-particle kiln slag is separated from the small-particle kiln slag and then sent to a salt-cooling process, resulting in a slag-containing mixture after cooling; the fine-particle kiln slag is sent to an air-cooling process, resulting in cold slag after cooling. This invention employs staged cooling of the kiln slag to improve cooling efficiency, while simultaneously enabling the large-particle kiln slag to be broken down and fully cooled during the water-cooling process.

[0061] In this invention, after pyrometallurgical enrichment, the resulting high-chlorine dust is mixed with sintering machine head ash to form a slurry. Since the slag-containing mixture contains a large amount of ammonia nitrogen, this invention, based on the characteristics of copper-ammonia complexation, introduces the slag-containing mixture to enhance the dissolution of copper ions from the sintering ash. The slag-containing mixture is then mixed with sintering machine head ash and high-chlorine dust to form a slurry. After slurry preparation, the slurry is coarsely separated to obtain a mixture containing fine particles. This mixture is then washed and filtered to obtain a washing liquid and a filter cake. The washing liquid contains a large amount of copper. Since the kiln slag obtained from the pyrometallurgical treatment of blast furnace bag ash has a large amount of elemental iron, cold slag is added to the washing liquid, causing an iron-copper displacement reaction, precipitating copper-containing materials. These precipitated copper-containing materials are then recovered and utilized through subsequent resource recovery methods.

[0062] In this invention, the reaction waste liquid is treated to remove heavy and hard substances, adjusted for alkali, and then evaporated to separate salts, yielding ammonia-nitrogen-containing condensate, potassium salts, sodium salts, and mother liquor, thus recovering sodium and potassium from high-salt solid waste. In addition to a large amount of chloride, the mother liquor also contains significant amounts of nitrate and sulfate ions. Based on the blast furnace bag filter ash treatment method for kiln slag, the mother liquor is acidified and then atomized to react with iron in high-temperature small-particle kiln slag, resulting in a high-concentration acidic ammonium sulfate and ammonium chloride solution, i.e., a slag-containing mixed liquor. During the co-washing process of the slag-containing mixed liquor and sintering machine head ash, the calcium in the sintering ash reacts with sulfate ions, achieving sulfate removal. Furthermore, the ammonia nitrogen in the slag-containing mixed liquor enhances the precipitation of copper ions from the sintering ash. Studies have shown that the reaction of iron with nitrate ions under acidic conditions mainly yields ammonia nitrogen, while under weakly acidic and neutral conditions, it mainly yields nitrogen gas. Therefore, to avoid the enrichment of ammonia nitrogen in the system, concentrated sulfuric acid is added to the mother liquor to adjust its pH to 2–7, based on the ammonia nitrogen concentration in the slag-containing mixed liquor. Simultaneously, the high temperature of the small-particle kiln slag and other associated substances (such as Cu) during the salt cooling process accelerate and catalyze the reaction between iron and nitrate ions. The generated nitrogen oxides are then recovered, completing the removal of nitrate ions from the mother liquor. This achieves the goal of mother liquor recycling and utilization.

[0063] In this invention, both the sintering machine head ash and the high-chlorine dust contain a certain concentration of ammonia nitrogen, and the mother liquor also produces ammonia nitrogen after iron reduction. Based on the characteristics of ammonia nitrogen, this invention designs a synergistic ash washing step. While achieving enhanced copper leaching, it utilizes an evaporation step to recover dilute ammonia water, which is then used in the pelletizing process of blast furnace bag ash. This reduces the generation of nitrogen oxides during rotary kiln roasting at the source, while the mother liquor is used for salt cooling of small-particle kiln slag.

[0064] In this invention, ammonia nitrogen is recovered through two methods: evaporation to recover dilute ammonia water and the reduction reaction of nitrate ions in the mother liquor with elemental iron. Furthermore, ammonia nitrogen is utilized through two other methods: returning dilute ammonia water to the rotary kiln for SNCR reaction and the complexation reaction of ammonia nitrogen in the slag-containing mixed liquor with copper.

[0065] In this invention, the pyrometallurgical enrichment of blast furnace ash produces high-chlorine dust and slag-containing mixed liquid, which is then mixed with sintered ash to form a slurry with a wide particle size distribution. Therefore, a hydrocyclone separator is introduced in the coarse separation process of the slurry, and a combination of slurry preparation, hydrocyclone, water washing, and filtration is adopted to ensure the stable operation of this technology and prevent problems such as uneven filter layer distribution and pipe blockage caused by direct water washing.

[0066] In this invention, large-particle kiln slag is obtained by gradient separation of kiln slag and sent to sintering to realize the high-value utilization of iron.

[0067] In this invention, in step 5), the slurry undergoes coarse separation via cyclone separation to obtain a mixture containing fine particles and coarse particles. The mixture containing fine particles proceeds to the next step, while the coarse particles are returned to the sintering process. In step 6), the copper-containing material is mainly composed of elemental copper, with other metals as dopants.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] 1. The present invention provides a method for synergistic water washing of sintering machine head ash and blast furnace bag ash. Based on the characteristics of blast furnace bag ash and sintering machine head ash, the blast furnace bag ash is first enriched by fire method, and then mixed with sintering machine head ash to make slurry, which solves the problems of large water consumption and large scale in the treatment of high-salt solid waste.

[0070] 2. The present invention provides a method for synergistic water washing of sintering machine head ash and blast furnace bag ash. It uses two methods to recover and utilize ammonia nitrogen in blast furnace bag ash and sintering machine head ash, and rationally disposes of nitrate and sulfate ions in mother liquor, thereby achieving zero discharge of waste liquid and preventing secondary pollution and rotary kiln corrosion.

[0071] 3. The present invention provides a method for synergistic water washing of sintering machine head ash and blast furnace bag ash, which effectively recovers copper resources from high-salt solid waste, increases the added value of machine head ash washing, and realizes high-value utilization of iron in kiln slag through gradient separation of kiln slag. Attached Figure Description

[0072] Figure 1 The flowchart illustrates a method for the synergistic washing of sintering machine head ash and blast furnace bag ash provided by this invention. Detailed Implementation

[0073] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0074] According to an embodiment of the present invention, a method for synergistic water washing of sintering machine head ash and blast furnace bag filter ash is provided.

[0075] A method for co-washing sintering machine head ash and blast furnace bag filter ash, the method comprising the following steps:

[0076] 1) Blast furnace bag ash is mixed with fuel and ammonia-containing water and pelletized to obtain green pellets. The green pellets are then roasted to obtain kiln slag and high-temperature flue gas.

[0077] 2) The high-temperature flue gas obtained in step 1) is cooled and dust removed to obtain high-chlorine dust and low-temperature flue gas;

[0078] 3) The kiln slag obtained in step 1) is screened to obtain large-particle kiln slag and small-particle kiln slag.

[0079] 4) After the small granular kiln slag is cooled with salt, a slag-containing mixture is obtained and / or fine granular kiln slag is separated from the small granular kiln slag, and the fine granular kiln slag is cooled with air to obtain cold slag.

[0080] 5) First, mix the high-chlorine dust obtained in step 2) with the sintering machine head ash, then add water and the slag-containing mixture obtained in step 4) to make a slurry. Perform hydrocyclone coarse separation on the slurry to obtain a mixture containing fine particles. Then, wash and filter the mixture containing fine particles to obtain a filter cake and a washing liquid.

[0081] 6) Add the cold residue obtained in step 4) to the washing liquid obtained in step 5) and react. After the reaction is completed, separate the copper-containing material and the reaction waste liquid.

[0082] 7) The reaction waste liquid obtained in step 6) is subjected to gravity and hardness removal treatment and then filtered to obtain filter residue and supernatant;

[0083] 8) First, adjust the supernatant obtained in step 7) to alkaline, then evaporate and separate the salts to obtain condensate containing ammonia nitrogen, potassium salt, sodium salt and mother liquor.

[0084] Preferably, the method further includes: 9) removing dust from the low-temperature flue gas obtained in step 2) to obtain secondary zinc oxide and clean flue gas.

[0085] Preferably, the method further includes: 10) the mother liquor obtained in step 8) is acidified and atomized and then recycled to step 4) to participate in salt cooling treatment.

[0086] Preferably, the mass ratio of blast furnace bag ash to fuel in step 1) is 50-100:1, more preferably 75-100:1.

[0087] Preferably, the moisture content of the blast furnace bag ash mixed with ammonia-containing water in step 1) is 10-14%, more preferably 11-13%.

[0088] Preferably, the ammonia nitrogen concentration in the ammonia-containing water in step 1) is 1000-3000 mg / L, more preferably 1500-2500 mg / L.

[0089] Preferably, the roasting temperature in step 1) is 1100–1500°C, more preferably 1100–1300°C.

[0090] Preferably, the roasting time in step 1) is 1.5 to 3 hours, more preferably 2 to 2.5 hours.

[0091] Preferably, the fuel in step 1) is one or both of pulverized coal and charcoal, with pulverized coal being the preferred choice.

[0092] Preferably, the cooling in step 2) is to cool the high-temperature flue gas to 150-200°C, more preferably 160-180°C.

[0093] Preferably, the cooling in step 2) is achieved by using a waste heat boiler and a surface cooler to cool the high-temperature flue gas.

[0094] Preferably, the dust removal process in step 2) involves using a bag filter to remove dust from the cooled high-temperature flue gas.

[0095] Preferably, the particle size of the large kiln slag particles in step 3) is greater than 20 mm, and more preferably 20 mm to 40 mm.

[0096] Preferably, the particle size of the small kiln slag particles in step 3) is less than 20 mm, and more preferably 3 to 20 mm.

[0097] Preferably, the fine kiln slag in step 4) has a particle size of less than 3 mm, and more preferably 0 to 3 mm.

[0098] Preferably, step 3) further includes: 31) the large granular kiln slag obtained in step 3) is cooled with water and then sent to the sintering process.

[0099] Preferably, the mass ratio of sintering machine head ash to high-chlorine dust in step 5) is 7-10:1, more preferably 8-9:1.

[0100] Preferably, the high-chlorine dust, sintering machine head ash, water and slag-containing mixture obtained in step 5) are used to obtain a slurry. The slurry is then subjected to coarse separation by cyclone separation to obtain a mixture containing fine particles. The mixture containing fine particles is then washed with water. During the mixing process, the solid-liquid ratio of the slurry is 0.25-0.5 kg / L, preferably 0.28-0.4 kg / L.

[0101] Preferably, the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is 2-6 kg / L, and more preferably 3-5 kg / L.

[0102] Preferably, the swirling process described in step 5) uses a swirling separator.

[0103] Preferably, step 5) further includes: 51) sending the obtained filter cake to the sintering process.

[0104] Preferably, the solid-liquid ratio of the cold slag and the washing liquid in step 6) is 1-5 g / L, and more preferably 2-3 g / L.

[0105] Preferably, the reaction time in step 6) is 0.5 to 1 hour, more preferably 0.6 to 0.8 hours.

[0106] Preferably, the degravation and hardening in step 7) involves adding a degravation agent and a hardening agent to the reaction waste liquid.

[0107] Preferably, the degravation agent is sodium sulfide or a degravation precipitator, and the amount added is 0.8-8 g / L, preferably 1-5 g / L.

[0108] Preferably, the hardening agent is sodium carbonate, and the amount added is 2-15 g / L, more preferably 3-10 g / L.

[0109] Preferably, the reaction time for weight removal and hardening removal is 0.5 to 2 hours, and more preferably 0.8 to 1.5 hours.

[0110] Preferably, step 8) involves adjusting the supernatant to alkalinity by using an alkaline solution to adjust the pH of the supernatant to 11-13; preferably, the alkaline solution is one or both of sodium hydroxide and potassium hydroxide.

[0111] Preferably, the salt separation by evaporation in step 8) is a multi-stage countercurrent evaporation, preferably a three-stage countercurrent evaporation.

[0112] Preferably, step 8) further includes: 81) adding the ammonia-containing nitrogen wastewater obtained in step 8) as ammonia-containing wastewater to the mixing and pelletizing process in step 1) and / or adding it as ash washing water to the washing process of the mixed liquid containing fine particles in step 5).

[0113] Preferably, the acidification in step 10) involves adjusting the pH of the mother liquor to 2-7 using concentrated sulfuric acid, more preferably 3-6.

[0114] Preferably, step 1) specifically involves: mixing blast furnace bag ash and fuel at a mass ratio of 50–100:1 (preferably 75–100:1); after mixing, adding ammonia-containing water with an ammonia nitrogen content of 1000–3000 mg / L (preferably 1500–2500 mg / L) at a moisture content of 10–14% (preferably 11–13%) to form pellets; sending the resulting green pellets into a rotary kiln; and calcining them in the rotary kiln at 1100–1500℃ (preferably 1100–1300℃) for 1.5–3 hours (preferably 2–2.5 hours) to obtain kiln slag and high-temperature flue gas.

[0115] Preferably, step 2) specifically involves: introducing the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler to cool it down to 150-200°C (preferably 160-180°C), and then separating the flue gas through a bag filter to obtain high-chlorine dust and low-temperature flue gas.

[0116] Preferably, step 3) specifically involves separating the kiln slag obtained in step 1) according to the particle size of the kiln slag, to obtain large-particle kiln slag with a particle size greater than or equal to 20 mm and small-particle kiln slag with a particle size less than 20 mm; wherein, the large-particle kiln slag is sent to the sintering process after being water-cooled.

[0117] Preferably, step 4) specifically involves: separating fine slag particles with a particle size of less than 3 mm from small slag particles with a particle size of less than 20 mm, sending the small slag particles with a particle size of 3 to 20 mm to salt cooling, obtaining a slag-containing mixture after salt cooling, and sending the fine slag particles with a particle size of less than 3 mm to air cooling, obtaining cold slag after air cooling.

[0118] Preferably, step 5) specifically involves: mixing the sintering machine head ash with the high-chlorine dust obtained in step 2) at a mass ratio of 7-10:1 (preferably 8-9:1), and adding the slag-containing mixture obtained in step 4) at a solid-liquid ratio of 0.25-0.5 kg / L (preferably 0.28-0.4 kg / L) to prepare a slurry. The slurry is then subjected to coarse separation to obtain a mixture containing fine particles. The mixture containing fine particles is then washed with water, and the water used for washing the ash is partly ammonia-nitrogen-containing condensate. The mixture is then filtered to obtain a filter cake and a washing liquid. The filter cake is then sent to the sintering process.

[0119] Preferably, step 6) specifically involves adding the cold slag obtained in step 4) to the washing liquid obtained in step 5) at a solid-liquid ratio of 1-5 g / L (preferably 2-3 g / L), reacting for 0.5-1 h (preferably 0.6-0.8 h), and then filtering to obtain copper-containing material and reaction waste liquid.

[0120] Preferably, step 7) specifically involves adding a weight removal agent and a hardening removal agent to the reaction waste liquid obtained in step 6), stirring and reacting for 0.5 to 2 hours (preferably 0.8 to 1.5 hours), and then filtering to obtain filter residue and supernatant; wherein the weight removal agent is sodium sulfide or a weight catching agent, and the amount added is 0.8 to 8 g / L (preferably 1 to 5 g / L); the hardening removal agent is sodium carbonate, and the amount added is 2 to 15 g / L (preferably 3 to 10 g / L).

[0121] Preferably, step 8) specifically involves: adjusting the pH of the supernatant obtained in step 7) to 11-13 using one or both of sodium hydroxide and potassium hydroxide; then introducing the pH-adjusted supernatant into an evaporation system; the supernatant sequentially passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor to obtain ammonia-nitrogen-containing wastewater condensate, potassium salt, sodium salt, and mother liquor; the ammonia-nitrogen-containing wastewater condensate is then used in the mixing and pelletizing process described in step 1); wherein the temperature in the triple-effect reactor is 20-60℃ (preferably 30-50℃), and the vacuum degree is -150 to -5. The temperature of the second-effect evaporation is 40-90℃ (preferably 50-80℃), and the vacuum degree is -100-30kPa (preferably -70-40kPa). The temperature of the first-effect evaporation is 70-105℃ (preferably 80-100℃), and the vacuum degree is -50-10kPa (preferably -40-15kPa). The condensate from the steam outlet of the third-effect reactor is collected, which is the ammonia-nitrogen-containing condensate. Preferably, the flow direction of the supernatant is opposite to the flow direction of the steam.

[0122] Preferably, step 9) specifically involves sending the low-temperature flue gas obtained in step 2) into a bag filter, and after dust removal, obtaining secondary zinc oxide and clean flue gas.

[0123] Preferably, step 10) specifically involves adjusting the pH of the mother liquor obtained in step 8) to 2-7 (preferably 3-6) with concentrated sulfuric acid, and then atomizing it before adding it as a high-salt cooling liquid to the salt cooling process described in step 4).

[0124] Example 1

[0125] A method for co-washing sintering machine head ash and blast furnace bag filter ash, the method comprising the following steps:

[0126] 1) Mix 84 kg of blast furnace bag ash with 0.84 kg of pulverized coal. After mixing, add condensate containing ammonia nitrogen with a nitrogen content of 2000 mg / L at a moisture content of 12% to form pellets. Send the resulting green pellets into a rotary kiln and calcine them at 1200℃ for 2 hours to obtain 63 kg of kiln slag and high-temperature flue gas.

[0127] 2) The high-temperature flue gas obtained in step 1) is introduced into the waste heat boiler and surface cooler. After the flue gas is cooled to 160°C, it is discharged. After being separated by a bag filter, 3.6 kg of high-chlorine dust and low-temperature flue gas are obtained.

[0128] 3) Separate the kiln slag obtained in step 1) to obtain 60kg of large-particle kiln slag with a particle size greater than or equal to 20mm and 3kg of small-particle kiln slag with a particle size less than 20mm. The large-particle kiln slag is sent to the sintering process after being cooled by water.

[0129] 4) Separate 0.5 kg of fine slag particles with a particle size of less than 3 mm from 3 kg of small slag particles with a particle size of less than 20 mm. Send 2.5 kg of small slag particles with a particle size of 3-20 mm to the salt cooling process. After salt cooling, 8 L of slag-containing mixed liquid is obtained. The fine slag particles with a particle size of less than 3 mm are sent to air cooling. After air cooling, 0.5 kg of cold slag is obtained.

[0130] 5) Mix the 3.6 kg of high-chlorine dust obtained in step 2) with 30 kg of sintering machine head ash (i.e., a mass ratio of 1:8.3), and add 8 L of the slag-containing mixed liquid obtained in step 4) at a solid-liquid ratio of 0.33 kg / L to prepare a slurry, 15.6 L of ammonia nitrogen-containing condensate, and 77.2 L of recycled water. Perform hydrocyclone coarse separation on the slurry to obtain 20 L of mixed liquid containing fine particles. Then, wash and filter the mixed liquid containing fine particles to obtain 18.1 kg of filter cake and 80 L of washing liquid. Send the filter cake to the sintering process.

[0131] 6) Add 0.16 kg of cold residue obtained in step 4) to the 80 L washing liquid obtained in step 5) at a solid-liquid ratio of 2 g / L. After reacting for 0.6 h, filter to obtain 0.2 kg of copper-containing material and 80 L of reaction waste liquid.

[0132] 7) Add 240g sodium sulfide and 400g sodium carbonate to the 80L reaction waste liquid obtained in step 6), stir and react for 1 hour, then filter to obtain 1kg filter residue and 79.7L supernatant.

[0133] 8) Adjust the pH of the supernatant obtained in step 7) to 12 with sodium hydroxide, and then introduce 80.5L of the pH-adjusted supernatant into the evaporation system. The supernatant passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor in sequence to obtain 24L of ammonia-nitrogen-containing condensate, 6kg of potassium chloride, 3.2kg of sodium chloride, and 8L of mother liquor. 8.4L of the ammonia-nitrogen-containing condensate is introduced into the pelletizing and mixing process described in step 1), and the remainder is returned to the water washing process described in step 5). The temperature in the triple-effect reactor is 40℃ and the vacuum degree is -80kPa; the temperature in the double-effect evaporation is 60℃ and the vacuum degree is -60kPa; and the temperature in the single-effect evaporation is 90℃ and the vacuum degree is -30kPa. The condensate from the steam outlet of the triple-effect reactor is collected, which is the ammonia-nitrogen-containing condensate. The flow direction of the supernatant is opposite to the flow direction of the steam.

[0134] 9) The low-temperature flue gas obtained in step 2) is sent into a bag filter. After dust removal, 14.4 kg of zinc oxide and clean flue gas are obtained.

[0135] 10) Adjust the pH of the 8L mother liquor obtained in step 8) to 5 with concentrated sulfuric acid, and after atomization, add it as a high-salt coolant to the salt cooling process described in step 4).

[0136] Example 2

[0137] A method for co-washing sintering machine head ash and blast furnace bag filter ash, the method comprising the following steps:

[0138] 1) Mix 84 kg of blast furnace bag ash with 0.84 kg of pulverized coal. After mixing, add condensate containing ammonia nitrogen with a nitrogen content of 2000 mg / L at a moisture content of 12% to form pellets. Send the resulting green pellets into a rotary kiln and calcine them at 1200℃ for 2 hours to obtain 63 kg of kiln slag and high-temperature flue gas.

[0139] 2) The high-temperature flue gas obtained in step 1) is introduced into the waste heat boiler and surface cooler. After the flue gas is cooled to 160°C, it is discharged. After being separated by a bag filter, 3.6 kg of high-chlorine dust and low-temperature flue gas are obtained.

[0140] 3) Separate the kiln slag obtained in step 1) to obtain 60kg of large-particle kiln slag with a particle size greater than or equal to 20mm and 3kg of small-particle kiln slag with a particle size less than 20mm. The large-particle kiln slag is sent to the sintering process after being cooled by water.

[0141] 4) Separate 0.5 kg of fine slag particles with a particle size of less than 3 mm from 3 kg of small slag particles with a particle size of less than 20 mm. Send 2.5 kg of small slag particles with a particle size of 3-20 mm to the salt cooling process. After salt cooling, 8 L of slag-containing mixed liquid is obtained. The fine slag particles with a particle size of less than 3 mm are sent to air cooling. After air cooling, 0.5 kg of cold slag is obtained.

[0142] 5) Mix the 3.6 kg of high-chlorine dust obtained in step 2) with 25.2 kg of sintering machine head ash (i.e., a mass ratio of 1:7), and add 8 L of the slag-containing mixed liquid obtained in step 4) at a solid-liquid ratio of 0.3 kg / L to prepare a slurry, 12 L of ammonia nitrogen-containing wastewater and 76 L of recycled water. Perform hydrocyclone coarse separation on the slurry to obtain 19 L of mixed liquid containing fine particles. Then, wash and filter the mixed liquid containing fine particles to obtain 17.5 kg of filter cake and 78.7 L of washing liquid. Send the filter cake to the sintering process.

[0143] 6) Add 0.157 kg of cold residue obtained in step 4) to the 78.7 L washing liquid obtained in step 5) at a solid-liquid ratio of 2 g / L. After reacting for 0.6 h, filter to obtain 0.192 kg of copper-containing material and 78.7 L of reaction waste liquid.

[0144] 7) Add 210g of sodium sulfide and 390g of sodium carbonate to the 78.7L of reaction waste liquid obtained in step 6), stir and react for 1 hour, then filter to obtain 1kg of filter residue and 78.5L of supernatant.

[0145] 8) Adjust the pH of the supernatant obtained in step 7) to 12 with sodium hydroxide, and then introduce 79.1L of the pH-adjusted supernatant into the evaporation system. The supernatant passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor in sequence to obtain 23.2L of ammonia-nitrogen-containing condensate, 5.8kg of potassium chloride, 3kg of sodium chloride, and 7.8L of mother liquor. 8.4L of the ammonia-nitrogen-containing condensate is introduced into the pelletizing and mixing process described in step 1), and 12L is returned to the water washing process described in step 5). The temperature in the triple-effect reactor is 40℃ and the vacuum degree is -80kPa; the temperature in the double-effect evaporation is 60℃ and the vacuum degree is -60kPa; the temperature in the single-effect evaporation is 90℃ and the vacuum degree is -30kPa. The condensate from the steam outlet of the triple-effect reactor is collected, which is the ammonia-nitrogen-containing condensate. The flow direction of the supernatant is opposite to the flow direction of the steam.

[0146] 9) The low-temperature flue gas obtained in step 2) is sent into a bag filter. After dust removal, 14.4 kg of zinc oxide and clean flue gas are obtained.

[0147] 10) Adjust the pH of the 7.8L mother liquor obtained in step 8) to 5 with concentrated sulfuric acid, and after atomization, add it as a high-salt coolant to the salt cooling process described in step 4).

[0148] Example 3

[0149] Repeat Example 1, except that the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is changed to 3 kg / L. After precipitation in step 6), 0.193 kg of copper-containing material is obtained.

[0150] Example 4

[0151] Repeat Example 1, except that the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is changed to 5 kg / L. After precipitation in step 6), 0.196 kg of copper-containing material is obtained.

[0152] Example 5

[0153] Repeat Example 1, except that the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is changed to 2 kg / L. After precipitation in step 6), 0.182 kg of copper-containing material is obtained.

[0154] Example 6

[0155] Repeat Example 1, except that the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is changed to 6 kg / L. After precipitation in step 6), 0.184 kg of copper-containing material is obtained.

[0156] Example 7

[0157] Repeat Example 1, except that the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixed liquid in step 5) is changed to 1 kg / L. After precipitation in step 6), 0.142 kg of copper-containing material is obtained.

[0158] Example 8

[0159] Repeat Example 1, except that the solid-liquid ratio of the high-chlorine dust, sintering machine head ash and slag-containing mixture in step 5) is changed to 8 kg / L. After precipitation in step 6), 0.149 kg of copper-containing material is obtained.

[0160] Example 9

[0161] Repeat Example 1, except that the solid-liquid ratio of the slurry during the mixing process in step 5) is 0.28 kg / L, and after precipitation in step 6), 0.196 kg of copper-containing material is obtained.

[0162] Example 10

[0163] Repeat Example 1, except that the solid-liquid ratio of the slurry during the mixing process in step 5) is 0.4 kg / L, and after precipitation in step 6), 0.198 kg of copper-containing material is obtained.

[0164] Example 11

[0165] Repeat Example 1, except that the solid-liquid ratio of the slurry during the mixing process in step 5) is 0.25 kg / L, and after precipitation in step 6), 0.188 kg of copper-containing material is obtained.

[0166] Example 12

[0167] Repeat Example 1, except that the solid-liquid ratio of the slurry during the mixing process in step 5) is 0.5 kg / L, and after precipitation in step 6), 0.190 kg of copper-containing material is obtained.

[0168] Example 13

[0169] Repeat Example 1, except that the solid-liquid ratio of the slurry during the mixing process in step 5) is 0.2 kg / L, and after precipitation in step 6), 0.152 kg of copper-containing material is obtained.

[0170] Example 14

[0171] Repeat Example 1, except that the solid-liquid ratio of the slurry during the mixing process in step 5) is 0.6 kg / L, and after precipitation in step 6), 0.158 kg of copper-containing material is obtained.

[0172] Example 15

[0173] Repeat Example 1, except that in step 6), the solid-liquid ratio of the washing liquid to the cold slag is 3 g / L, and 1.98 kg of copper-containing material is obtained.

[0174] Example 16

[0175] Repeat Example 1, except that in step 6), the solid-liquid ratio of the washing liquid to the cold slag is 1 g / L, and 1.86 kg of copper-containing material is obtained.

[0176] Example 17

[0177] Repeat Example 1, except that in step 6), the solid-liquid ratio of the washing liquid to the cold slag is 5 g / L, to obtain 1.90 kg of copper-containing material.

[0178] Example 18

[0179] Repeat Example 1, except that in step 6), the solid-liquid ratio of the washing liquid to the cold slag is 0.5 g / L, resulting in 1.47 kg of copper-containing material.

[0180] Example 19

[0181] Repeat Example 1, except that in step 6), the solid-liquid ratio of the washing liquid to the cold slag is 7 g / L, to obtain 1.55 kg of copper-containing material.

Claims

1. A method for synergistic water washing of sintering machine head ash and blast furnace bag filter ash, characterized in that: The method includes the following steps: 1) Blast furnace bag ash is mixed with fuel and ammonia-containing water and pelletized to obtain green pellets. The green pellets are then roasted to obtain kiln slag and high-temperature flue gas. 2) The high-temperature flue gas obtained in step 1) is cooled and dust removed to obtain high-chlorine dust and low-temperature flue gas; 3) The kiln slag obtained in step 1) is screened to obtain large-particle kiln slag and small-particle kiln slag. 4) After the small granular kiln slag is cooled with salt, a slag-containing mixture is obtained and / or fine granular kiln slag is separated from the small granular kiln slag, and the fine granular kiln slag is cooled with air to obtain cold slag. 5) First, mix the high-chlorine dust obtained in step 2) with the sintering machine head ash, then add water and the slag-containing mixture obtained in step 4) to make a slurry. Perform hydrocyclone coarse separation on the slurry to obtain a mixture containing fine particles. Then, wash and filter the mixture containing fine particles to obtain a filter cake and a washing liquid. 6) Add the cold residue obtained in step 4) to the washing liquid obtained in step 5) to react. After the reaction is completed, separate the copper-containing material and the reaction waste liquid. 7) The reaction waste liquid obtained in step 6) is subjected to gravity and hardness removal treatment and then filtered to obtain filter residue and supernatant; 8) First, adjust the pH of the supernatant obtained in step 7) to 11-13 using alkaline solution, then evaporate and separate the salts to obtain ammonia-nitrogen-containing condensate, potassium salt, sodium salt, and mother liquor; the evaporation and salt separation in step 8) is a multi-stage countercurrent evaporation; add the obtained ammonia-nitrogen-containing condensate as ammonia-containing wastewater to the mixing and pelletizing process in step 1) and / or add it as ash washing water to the water washing process of the mixed liquid containing fine particles in step 5); 9) The low-temperature flue gas obtained in step 2) is subjected to dust removal to obtain secondary zinc oxide and clean flue gas; 10) The mother liquor obtained in step 8) is acidified and atomized, and then recycled to step 4) to participate in the salt cooling treatment.

2. The method according to claim 1, characterized in that: Step 1) The mass ratio of blast furnace bag ash to fuel is 50~100:1; and / or The moisture content of the blast furnace bag ash mixed with ammonia-containing water in step 1) is 10-14%; and / or Step 1) The ammonia nitrogen concentration in the ammonia-containing water is 1000~3000 mg / L; and / or The calcination temperature in step 1) is 1100~1500℃; and / or The roasting time in step 1) is 1.5~3 hours; and / or The fuel mentioned in step 1) is one or both of pulverized coal and charcoal.

3. The method according to claim 2, characterized in that: Step 1) The mass ratio of blast furnace bag ash to fuel is 75~100:1; and / or The moisture content of the blast furnace bag ash mixed with ammonia-containing water in step 1) is 11-13%; and / or Step 1) The ammonia nitrogen concentration in the ammonia-containing water is 1500~2500 mg / L; and / or The calcination temperature in step 1) is 1100~1300℃; and / or The roasting time in step 1) is 2~2.5h; and / or The fuel mentioned in step 1) is pulverized coal.

4. The method according to claim 1, characterized in that: Step 2) cooling refers to cooling the high-temperature flue gas to 150~200℃; and / or Step 2) cooling refers to cooling the high-temperature flue gas using a waste heat boiler and a surface cooler; and / or Step 2) describes a dust removal process that uses a bag filter to remove dust from the cooled, high-temperature flue gas.

5. The method according to claim 4, characterized in that: The cooling described in step 2) is to cool the high-temperature flue gas to 160~180℃.

6. The method according to claim 1, characterized in that: Step 3) The large-particle kiln slag has a particle size greater than 20 mm; and / or The small granular kiln slag particles mentioned in step 3) have a particle size of less than 20 mm; and / or The fine-particle kiln slag mentioned in step 4) has a particle size of less than 3 mm; and / or Step 3) also includes: 31) After the large-particle kiln slag obtained in step 3) is cooled by water, it is sent to the sintering process.

7. The method according to claim 1, characterized in that: Step 5) The mass ratio of sintering machine head ash to high-chlorine dust is 7~10:1; and / or Step 5) The high-chlorine dust, sintering machine head ash and slag-containing mixed liquid are used to obtain a slurry. The slurry is subjected to coarse separation by hydrocyclone to obtain a mixed liquid containing fine particles. Then the mixed liquid containing fine particles is washed with water. During the mixing process, the solid-liquid ratio of the slurry is 0.25~0.5kg / L. and / or The cyclone process described in step 5) employs a cyclone separator; and / or Step 5) also includes: 51) sending the obtained filter cake to the sintering process; and / or The solid-liquid ratio of the cold slag and washing liquid in step 6) is 1~5 g / L; and / or The reaction time in step 6) is 0.5 to 1 hour.

8. The method according to claim 7, characterized in that: Step 5) The mass ratio of sintering machine head ash to high-chlorine dust is 8~9:1; and / or Step 5) The solid-liquid ratio of the slurry during mixing is 0.28~0.4 kg / L; and / or The solid-liquid ratio of the cold slag and washing liquid in step 6) is 2~3 g / L; and / or The reaction time in step 6) is 0.6~0.8h.

9. The method according to claim 1, characterized in that: Step 7) involves adding a weight removal agent and a hardening removal agent to the reaction waste liquid.

10. The method according to claim 9, characterized in that: The degravity removal agent is sodium sulfide or a gravity precipitator, added at a concentration of 0.8~8 g / L; and / or The hardening agent is sodium carbonate, and the amount added is 2~15g / L.

11. The method according to claim 10, characterized in that: The amount of the scavenging agent added is 1~5 g / L; and / or The amount of the hardening agent added is 3~10g / L.

12. The method according to claim 9, characterized in that: The reaction time for removing weight and hardness is 0.5~2 hours.

13. The method according to claim 12, characterized in that: The reaction time for degravation and dehardening is 0.8~1.5h.

14. The method according to claim 1, characterized in that: Step 8) The alkaline solution is one or both of sodium hydroxide and potassium hydroxide; and / or Step 8) describes a three-stage countercurrent evaporation process for salt separation.

15. The method according to claim 1, characterized in that: The acidification described in step 10) involves adjusting the pH of the mother liquor to 2-7 using concentrated sulfuric acid.

16. The method according to claim 15, characterized in that: The acidification described in step 10) involves adjusting the pH of the mother liquor to 3-6 using concentrated sulfuric acid.

17. The method according to any one of claims 1-16, characterized in that: Step 1) specifically involves: mixing blast furnace bag ash and fuel at a mass ratio of 50-100:1; after mixing, adding ammonia-containing water with an ammonia nitrogen content of 1000-3000 mg / L at a moisture content of 10-14% to form pellets; sending the resulting green pellets into a rotary kiln and calcining them at 1100-1500℃ for 1.5-3 hours to obtain kiln slag and high-temperature flue gas; and / or Step 2) specifically involves: introducing the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler to cool it down to 150~200℃; then, after the flue gas is separated by a bag filter, high-chlorine dust and low-temperature flue gas are obtained; and / or Step 3) specifically involves separating the kiln slag obtained in step 1) according to its particle size, resulting in large-particle kiln slag with a particle size greater than or equal to 20 mm and small-particle kiln slag with a particle size less than 20 mm; wherein, the large-particle kiln slag is sent to the sintering process after water cooling; and / or Step 4) specifically involves: separating fine slag particles with a particle size of less than 3 mm from small slag particles with a particle size of less than 20 mm; sending the small slag particles with a particle size of 3-20 mm to a salt cooler; after salt cooling, a slag-containing mixture is obtained; and sending the fine slag particles with a particle size of less than 3 mm to an air cooler; after air cooling, cold slag is obtained; and / or Step 5) specifically involves: mixing the sintering machine head ash with the high-chlorine dust obtained in step 2) at a mass ratio of 7-10:1, and adding the slag-containing mixture obtained in step 4) at a solid-liquid ratio of 0.25-0.5 kg / L to prepare a slurry. The slurry undergoes coarse separation to obtain a mixture containing fine particles. This mixture is then washed with water, using a portion of the water containing ammonia and nitrogen as condensate. The mixture is filtered to obtain a filter cake and washing liquid. The filter cake is then sent to the sintering process; and / or Step 6) specifically involves adding the cold slag obtained in step 4) to the washing liquid obtained in step 5) at a solid-liquid ratio of 1-5 g / L, reacting for 0.5-1 h, and then filtering to obtain copper-containing material and reaction waste liquid; and / or Step 7) specifically involves: adding a weight removal agent and a hardening removal agent to the reaction waste liquid obtained in step 6), stirring the reaction for 0.5 to 2 hours, and then filtering to obtain filter residue and supernatant; wherein the weight removal agent is sodium sulfide or a weight precipitator, and the amount added is 0.8 to 8 g / L; the hardening removal agent is sodium carbonate, and the amount added is 2 to 15 g / L; and / or Step 8) specifically involves: adjusting the pH of the supernatant obtained in step 7) to 11-13 using one or both of sodium hydroxide and potassium hydroxide; then introducing the pH-adjusted supernatant into an evaporation system, where the supernatant sequentially passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor to obtain ammonia-nitrogen-containing condensate, potassium salts, sodium salts, and mother liquor; the ammonia-nitrogen-containing condensate is then used in the mixing and pelletizing process of step 1); wherein the temperature in the triple-effect reactor is 20-60℃, and the vacuum degree is -150 to -50 kPa; the temperature in the double-effect evaporation is 40-90℃, and the vacuum degree is -100 to -30 kPa; the temperature in the single-effect evaporation is 70-105℃, and the vacuum degree is -50 to -10 kPa; collecting the condensate from the steam outlet of the triple-effect reactor, which is the ammonia-nitrogen-containing condensate; and / or Step 9) specifically involves: feeding the low-temperature flue gas obtained in step 2) into a bag filter, and after dust removal, obtaining secondary zinc oxide and clean flue gas; and / or Specifically, step 10) involves adjusting the pH of the mother liquor obtained in step 8) to 2-7 with concentrated sulfuric acid, and then atomizing it before adding it as a high-salt cooling liquid to the salt cooling process described in step 4).

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