Synergistic washing method for sintering machine head ash and blast furnace cloth bag ash

Abstract

A collaborative washing method for sintering machine head ash and blast furnace cloth bag ash comprises the steps that according to the characteristics of the blast furnace cloth bag ash and the sintering machine head ash, the blast furnace cloth bag ash is enriched through a pyrogenic process and then mixed with the sintering machine head ash for pulping, and the problems that in the high-salt solid waste treatment process, the water consumption is large, and the scale is large are solved; meanwhile, ammonia nitrogen in blast furnace cloth bag ash and sintering machine head ash is recovered and utilized by adopting two methods, nitrate radicals and sulfate radicals in mother liquor are reasonably treated, zero emission of waste liquor is achieved, and secondary pollution and rotary kiln corrosion are prevented.

Description

Technical Field

[0001] The present invention relates to a collaborative water washing method, specifically to a collaborative water washing method for sintering machine head ash and blast furnace bag dust, belonging to the technical field of sintering. Background Art

[0002] Steel plants contain a large amount of high-salt solid waste, such as sintering three and four electric field ash, blast furnace bag dust removal ash, which contains more alkali and chlorine metals and cannot be directly returned to the system for consumption to avoid equipment corrosion and adverse situations such as kiln blocking. Currently, generally, the removal of alkali and chlorine metals is carried out by water washing, and the wastewater is disposed of and the crystal salt is recovered by evaporation crystallization.

[0003] Chinese Patent CN101234766A, "Method for Producing Potassium Chloride by Using Sintering Electrostatic Precipitation Ash of Iron and Steel Enterprises", reports a method of leaching sintering machine head ash with a compound solution of tap water and SDD inhibitor, and the leaching rate of potassium and sodium can reach 95-99.5%. Chinese Patent CN103435073A, "Method for Producing Potassium Chloride by Using Blast Furnace Gas Ash of Iron and Steel Enterprises", reports the use of tap water to leach blast furnace gas ash, greatly reducing potassium and chlorine in the blast furnace gas ash, and using the obtained leaching solution to prepare potassium chloride and sodium chloride.

[0004] In the process of treating high-salt solid waste in steel plants, evaporation crystallization is often used. The process of evaporating and crystallizing salt is actually a process of continuously concentrating the solution. At the same time, since the leaching solution contains, in addition to chloride salts, sulfate ions, nitrate ions, etc., these ions will cause cyclic enrichment as the solution is continuously concentrated. The traditional method is to add the mother liquor to the rotary kiln by spraying or batching, or to directly discharge it to avoid the influence of the mother liquor on the crystal salt. Adding the mother liquor to the rotary kiln by spraying or batching easily causes corrosion of the rotary kiln, while direct discharge will cause secondary pollution.

[0005] Currently, for sintering machine head ash and blast furnace bag dust, generally, an independent water washing and resource utilization method is adopted. The chlorine content in blast furnace bag dust is generally 4-10%, and its amount is generally 3 times that of sintering machine head ash. If directly washed for dechlorination, the equipment is large and the water volume is large, the equipment occupies a large area, and it is not conducive to water conservation. The blast furnace bag dust and sintering machine head ash produced by steel plants are both high-chlorine solid wastes and need to be washed for dechlorination treatment. Collaborative treatment is a better way to reduce investment and operation. However, the existing methods only simply mix and treat the blast furnace bag dust and sintering machine head ash without considering the characteristics of solid waste and material treatment.

[0006] In addition, there is more copper in the sintering machine head ash. During the water washing process, a copper-rich solution will be obtained. At present, the common practice is direct precipitation treatment without effective utilization, resulting in waste of resources.

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

[0008] In view of the problems existing in the current disposal process of sintering machine head ash and blast furnace bag dust, such as large water consumption and improper disposal methods for copper ions, nitrate, and sulfate, the present invention proposes a coordinated water washing method for sintering machine head ash and blast furnace bag dust. The blast furnace bag dust is treated by pyrometallurgy, and the high-chlorine dust obtained after the flue gas is cooled is used. At the same time, the kiln slag is classified by particle size and then cooled, and the obtained product is used for the disposal of sintering machine head ash. According to the characteristics of blast furnace bag dust and sintering machine head ash, they are treated separately, achieving the goal of zero liquid discharge.

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

[0010] A coordinated water washing method for sintering machine head ash and blast furnace bag dust, the method comprising the following steps:

[0011] 1) Mix the blast furnace bag dust with fuel and ammonia water to make green balls, and then roast the green balls to obtain kiln slag and high-temperature flue gas;

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

[0013] 3) Screen the kiln slag obtained in step 1) to obtain large-particle kiln slag and small-particle kiln slag;

[0014] 4) After salt cooling the small-particle kiln slag, a slag-containing mixed liquid is obtained and / or fine-particle kiln slag is separated from the small-particle kiln slag, and the fine-particle kiln slag is air-cooled to obtain cold slag;

[0015] 5) First, mix the high-chlorine dust obtained in step 2) with sintering machine head ash, then add water and the slag-containing mixed liquid obtained in step 4) to prepare a slurry. The slurry is subjected to hydrocyclone rough separation to obtain a fine-particle-containing mixed liquid, and then the fine-particle-containing mixed liquid is washed and filtered to obtain a filter cake and washing liquid;

[0016] 6) Add the cold slag obtained in step 4) to the washing liquid obtained in step 5) for reaction. After the reaction is completed, a copper-containing material and reaction waste liquid are separated;

[0017] 7) The reaction waste liquid obtained in step 6) is subjected to heavy metal 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, and then evaporate and separate salts to obtain ammonia-nitrogen-containing sewage condensate, potassium salt, sodium salt, and mother liquor.

[0019] Preferably, the method further includes: 9) After dedusting the low-temperature flue gas obtained in step 2), secondary zinc oxide and clean flue gas are obtained.

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

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

[0022] Preferably, the moisture content after mixing the blast furnace bag dust and ammonia-containing water in step 1) is 10-14%, preferably 11-13%.

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

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

[0025] Preferably, the roasting time in step 1) is 1.5-3 h, preferably 2-2.5 h.

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

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

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

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

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

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

[0032] Preferably, the particle size of the fine particle kiln slag in step 4) is less than 3 mm, preferably 0-3 mm.

[0033] Preferably, step 3) further includes: 31) After water-cooling the large particle kiln slag obtained in step 3), it is sent to the sintering process.

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

[0035] Preferably, the high-chlorine dust, sintering machine head ash, water and slag-containing mixed liquid described in step 5) are used to obtain a slurry, the slurry is subjected to cyclone coarse separation to obtain a mixed liquid containing fine particles, and 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 to 0.5 kg / L, preferably 0.28 to 0.4 kg / L.

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

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

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

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

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

[0041] Preferably, the step 7) of removing heavy substances and hard substances is as follows: adding a heavy substance removal agent and a hard substance removal agent to the reaction waste liquid.

[0042] Preferably, the de-heavy agent is sodium sulfide or a heavy capture agent, and the addition amount is 0.8 to 8 g / L, preferably 1 to 5 g / L.

[0043] Preferably, the hardness removing agent is sodium carbonate, and the added amount is 2 to 15 g / L, preferably 3 to 10 g / L.

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

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

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

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

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

[0049] Preferably, the step 1) is specifically as follows: mixing blast furnace bag ash and fuel in a mass ratio of 50 to 100:1 (preferably 75 to 100:1), adding ammonia water with an ammonia nitrogen content of 1000 to 3000 mg / L (preferably 1500 to 2500 mg / L) at a moisture content of 10 to 14% (preferably 11 to 13%) to make balls, sending the obtained green balls into a rotary kiln, and roasting them at 1100 to 1500° C. (preferably 1100 to 1300° C.) in the rotary kiln for 1.5 to 3 hours (preferably 2 to 2.5 hours) to obtain kiln slag and high-temperature flue gas.

[0050] Preferably, the step 2) is specifically as follows: the high-temperature flue gas obtained in step 1) is introduced into a waste heat boiler and a surface cooler to cool the flue gas to 150-200°C (preferably 160-180°C), and the flue gas is separated by a bag filter to obtain high-chlorine dust and low-temperature flue gas.

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

[0052] Preferably, the step 4) is specifically as follows: separating fine-particle slag with a particle size of less than 3 mm from small-particle slag with a particle size of less than 20 mm, sending the small-particle slag with a particle size of 3 to 20 mm to salt cooling, and obtaining a slag-containing mixed liquid after the salt cooling is completed; sending the fine-particle slag with a particle size of less than 3 mm to air cooling, and obtaining cold slag after the air cooling is completed.

[0053] Preferably, the step 5) is specifically as follows: the sintering machine head ash and the high chlorine dust obtained in step 2) are mixed in a mass ratio of 7 to 10:1 (preferably 8 to 9:1), and the slag-containing mixed liquid obtained in step 4) is added at a solid-liquid ratio of 0.25 to 0.5 kg / L (preferably 0.28 to 0.4 kg / L) to prepare a slurry, the slurry is coarsely separated to obtain a mixed liquid containing fine particles, and then the mixed liquid containing fine particles is washed with water, and the water part used for washing the ash is ammonia nitrogen-containing condensed water, which is filtered to obtain a filter cake and a water washing liquid; and the filter cake is then sent to the sintering process.

[0054] Preferably, the step 6) is specifically: adding the cold slag obtained in step 4) to the water 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 a copper-containing material and a reaction waste liquid.

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

[0056] Preferably, the step 8) is specifically: using one or both of sodium hydroxide and potassium hydroxide to adjust the pH of the supernatant obtained in step 7) to 11-13, then introducing the supernatant after adjusting the pH into the evaporation system, and the supernatant passes through a three-effect reactor, a two-effect reactor and a one-effect reactor in sequence to obtain ammonia nitrogen-containing condensed water, potassium salt, sodium salt and mother liquor; and then using the ammonia nitrogen-containing condensed water in the mixing and pelletizing process described in step 1); wherein the temperature in the three-effect reactor is 20-60°C (preferably 30-50°C), and the vacuum degree is -150--5 0kPa (preferably -100 to -70kPa), the temperature of the second-effect evaporation is 40 to 90°C (preferably 50 to 80°C), and the vacuum degree is -100 to -30kPa (preferably -70 to -40kPa), the temperature of the first-effect evaporation is 70 to 105°C (preferably 80 to 100°C), and the vacuum degree is -50 to -10kPa (preferably -40 to -15kPa); the condensed water at the steam outlet of the triple-effect reactor is collected, that is, the ammonia-nitrogen-containing condensed water; preferably, the flow direction of the supernatant is opposite to the flow direction of the steam.

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

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

[0059] In the present invention, first, the blast furnace bag dust is enriched by pyrometallurgy. After the blast furnace bag dust is pelletized by mixing with pulverized coal and ammonia-containing water and then roasted, chlorides, zinc, lead, etc. in the blast furnace bag dust will decompose and volatilize into the flue gas, while the iron therein remains in the slag phase, obtaining kiln slag and high-temperature flue gas with a high chlorine content. Then, through the gradient cooling of the high-temperature flue gas, the enrichment of lead and chlorine in the dust is achieved. After detection, for the high-chlorine dust obtained by pyrometallurgical enrichment, the chlorine content can reach 20-30%, and the mass of the high-chlorine dust is only 3-10% of the mass of the blast furnace bag dust. Washing the enriched high-chlorine dust can significantly reduce the scale and amount of washing water. In addition, through comparison, it is found that when washing the high-chlorine dust, compared with directly washing the blast furnace bag dust, the water quality of the washing liquid obtained is better, 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 the present invention, according to the characteristics of the kiln slag and the requirements of subsequent utilization, the obtained kiln slag is cooled in a cascade manner. The large-particle kiln slag is sent to the water-cooling process; and the fine-particle kiln slag is separated from the small-particle kiln slag, and then the small-particle kiln slag is sent to the salt-cooling process. After cooling, a slag-containing mixed liquid is obtained; the fine-particle kiln slag is sent to the air-cooling process, and cold slag is obtained after cooling. The present invention provides a cascade cooling of the kiln slag, which improves the cooling efficiency and at the same time enables the large-particle kiln slag to be crushed during the water-cooling process and be fully cooled.

[0061] In the present invention, after the blast furnace ash is enriched by pyrometallurgy, the obtained high-chlorine dust is mixed with the sintering machine head ash to make a slurry. Since the slag-containing mixed liquid contains a large amount of ammonia nitrogen, based on the characteristics of copper-ammonia complexation in the present invention, the slag-containing mixed liquid is introduced to strengthen the dissolution of copper ions in the sintering ash. The slag-containing mixed liquid is mixed with the sintering machine head ash and the high-chlorine dust to make a slurry. After the slurry is coarsely separated, a fine-particle-containing mixed liquid is obtained, and then the fine-particle-containing mixed liquid is washed and filtered to obtain a washing liquid and a filter cake. The washing liquid contains a large amount of copper. Utilizing the characteristic that the kiln slag obtained by pyrometallurgical treatment of the blast furnace bag dust has a large amount of elemental iron, cold slag is added to the washing liquid, and an iron displacement copper reaction occurs to precipitate copper-containing materials. The precipitated copper-containing materials are recycled through subsequent resource utilization means.

[0062] In the present invention, the reaction waste liquid is deweighted, dehardened, pH-adjusted with alkali, and subjected to evaporation and salt separation to obtain ammonia-nitrogen-containing sewage condensate, potassium salts, sodium salts, and mother liquor, thus completing the recovery of sodium and potassium in the high-salt solid waste. In addition, besides containing a large amount of chlorine, the mother liquor also contains a large amount of nitrate and sulfate. Based on the pyrometallurgical treatment of blast furnace bag dust to obtain slag, after acidifying and regulating the mother liquor, it is atomized and reacted with iron in the high-temperature small-particle slag to obtain a high-concentration acidic ammonium sulfate and ammonium chloride solution, namely the slag-containing mixed liquid. During the collaborative water washing process of the slag-containing mixed liquid and sintering machine head ash, the calcium in the sintering ash reacts with sulfate ions to achieve the removal of sulfate. In addition, the ammonia nitrogen in the slag-containing mixed liquid will enhance the precipitation of copper ions in the sintering ash. Research shows that the reaction of iron with nitrate mainly produces ammonia nitrogen under acidic conditions, while mainly produces nitrogen under weakly acidic and neutral conditions. Therefore, to avoid the enrichment of ammonia nitrogen in the system, according to the ammonia nitrogen concentration in the slag-containing mixed liquid, concentrated sulfuric acid is added to the mother liquor to adjust the pH of the mother liquor to 2-7. At the same time, during the salt cooling process, the high temperature of the small-particle slag and other accompanying substances (such as Cu, etc.) will accelerate and catalyze the reaction of iron with nitrate ions, and then the generated nitrogen oxides are recovered to complete the removal of nitrate ions in the mother liquor. The purpose of recycling, consuming, and utilizing the mother liquor is achieved.

[0063] In the present invention, both the sintering machine head ash and the high-chlorine dust contain a certain concentration of ammonia nitrogen, and ammonia nitrogen will also be produced after the mother liquor is reduced by iron. Based on the characteristics of ammonia nitrogen, the present invention designs a collaborative ash washing step. While realizing the enhanced dissolution of copper, the evaporation step is used to recover dilute ammonia water, and the dilute ammonia water is used for the pelletizing process of blast furnace bag dust, so as to reduce the generation of nitrogen oxides during the roasting process of the rotary kiln at the source, and the mother liquor is used for the salt cooling of the small-particle slag.

[0064] In the present invention, the recovery of ammonia nitrogen is completed through two methods: evaporation to recover dilute ammonia water and the reduction reaction of nitrate in the mother liquor with elemental iron. And the utilization of ammonia nitrogen is completed through two methods: returning the dilute ammonia water to the rotary kiln for roasting to occur the SNCR reaction and the complexation reaction of ammonia nitrogen and copper in the slag-containing mixed liquid.

[0065] In the present invention, the pyrometallurgical enrichment of blast furnace ash produces high-chlorine dust and a slag-containing mixed liquid, which are mixed with sintering ash to make pulp, and the particle size distribution is relatively wide. Therefore, a hydrocyclone is introduced in the coarse separation process of the pulp, and a combined process of pulping, hydrocycloning, water washing, and filtration is adopted to ensure the stable operation of the present technology and prevent problems such as uneven filter layer distribution and pipeline blockage caused by direct water washing.

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

[0067] In the present invention, in step 5), the slurry is subjected to hydrocyclone rough separation to obtain a fine-particle-containing mixed liquid and coarse particles. The fine-particle-containing mixed liquid enters the next step, while the coarse particles are returned to the sintering process. The main component of the copper-containing material in step 6) is elemental copper and is doped with other metals.

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

[0069] 1. A collaborative water washing method for sintering machine head ash and blast furnace bag filter ash provided by the present invention, according to the characteristics of blast furnace bag filter ash and sintering machine head ash, first fire-enriches the blast furnace bag filter ash, and then mixes it with the sintering machine head ash to make a slurry, solving the problems of large water consumption and large scale in the process of treating high-salt solid waste.

[0070] 2. A collaborative water washing method for sintering machine head ash and blast furnace bag filter ash provided by the present invention, uses two methods to recover and utilize the ammonia nitrogen in the blast furnace bag filter ash and sintering machine head ash, reasonably disposes of the nitrate and sulfate in the mother liquor, realizes zero discharge of waste liquid, prevents secondary pollution and rotary kiln corrosion.

[0071] 3. A collaborative water washing method for sintering machine head ash and blast furnace bag filter ash provided by the present invention, effectively recovers the copper resources in the high-salt solid waste, improves the added value of the water washing of the machine head ash, and also realizes the high-value utilization of iron in the kiln slag through the gradient separation of the kiln slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a flow chart of a collaborative water washing method for sintering machine head ash and blast furnace bag filter ash provided by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0073] The technical solutions of the present invention will be illustrated below. The scope of protection claimed by the present invention includes but is not limited to the following embodiments.

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

[0075] A collaborative water washing method for sintering machine head ash and blast furnace bag filter ash, the method includes the following steps:

[0076] 1) Mix the blast furnace bag filter ash with fuel and ammonia water to make pellets, and then roast the pellets to obtain kiln slag and high-temperature flue gas;

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

[0078] 3) Screen the kiln slag obtained in step 1) to obtain large-particle kiln slag and small-particle kiln slag;

[0079] 4) The small particle slag is salt-cooled to obtain a slag-containing mixed liquid and / or the fine particle slag is separated from the small particle slag, and the fine particle slag is air-cooled to obtain cold slag;

[0080] 5) First, the high-chlorine dust obtained in step 2) is mixed with the sintering machine head ash, then water and the slag-containing mixed liquid obtained in step 4) are added to prepare a slurry. The slurry is subjected to cyclone rough separation to obtain a fine particle-containing mixed liquid, and then the fine particle-containing mixed liquid is washed and filtered to obtain a filter cake and a washing liquid;

[0081] 6) Cold slag obtained in step 4) is added to the washing liquid obtained in step 5) for reaction. After the reaction is completed, a copper-containing material and reaction waste liquid are separated;

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

[0083] 8) First, the supernatant obtained in step 7) is adjusted to alkaline, and then evaporated to separate salts, obtaining ammonia nitrogen-containing sewage condensate, potassium salts, sodium salts, and mother liquor.

[0084] Preferably, the method further includes: 9) The low-temperature flue gas obtained in step 2) is dust-removed 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 the blast furnace bag dust to the fuel in step 1) is 50-100:1, preferably 75-100:1.

[0087] Preferably, the moisture content after the blast furnace bag dust and the ammonia-containing water are mixed in step 1) is 10-14%, preferably 11-13%.

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

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

[0090] Preferably, the roasting time in step 1) is 1.5-3 h, preferably 2-2.5 h.

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

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

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

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

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

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

[0097] Preferably, the particle size of the fine particle kiln slag in step 4) is less than 3 mm, preferably 0 - 3 mm.

[0098] Preferably, step 3) further includes: 31) After the large particle kiln slag obtained in step 3) is cooled by water, it is sent to the sintering process.

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

[0100] Preferably, in step 5), the high-chlorine dust, the sintering machine head ash, water and the slag-containing mixed liquid are made into a slurry. The slurry is subjected to hydrocyclone rough separation to obtain a fine particle-containing mixed liquid, and then the fine particle-containing mixed liquid is washed. 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, the sintering machine head ash and the slag-containing mixed liquid in step 5) is 2 - 6 kg / L, preferably 3 - 5 kg / L.

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

[0103] Preferably, step 5) further includes: 51) The obtained filter cake is sent 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, preferably 2 - 3 g / L.

[0105] Preferably, the reaction time in step 6) is 0.5 - 1 h, preferably 0.6 - 0.8 h.

[0106] Preferably, the heavy metal removal and hardness removal in step 7) is: adding heavy metal removal agents and hardness removal agents to the reaction waste liquid.

[0107] Preferably, the deweighting agent is sodium sulfide or heavy metal capturer, and the addition amount is 0.8 - 8 g / L, preferably 1 - 5 g / L.

[0108] Preferably, the water softening agent is sodium carbonate, and the addition amount is 2 - 15 g / L, preferably 3 - 10 g / L.

[0109] Preferably, the reaction time for deweighting and water softening is 0.5 - 2 h, preferably 0.8 - 1.5 h.

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

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

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

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

[0114] Preferably, step 1) is specifically: mixing blast furnace bag dust and fuel at a mass ratio of 50 - 100:1 (preferably 75 - 100:1), adding ammonia-containing water with an ammonia nitrogen content of 1000 - 3000 mg / L (preferably 1500 - 2500 mg / L) to pelletize at a moisture content of 10 - 14% (preferably 11 - 13%) after mixing, feeding the obtained green pellets into a rotary kiln, and roasting at 1100 - 1500 °C (preferably 1100 - 1300 °C) in the rotary kiln for 1.5 - 3 h (preferably 2 - 2.5 h) to obtain kiln slag and high-temperature flue gas.

[0115] Preferably, step 2) is specifically: introducing the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler, cooling it 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) is specifically: 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; among them, the large particle kiln slag is sent to the sintering process after being water-cooled.

[0117] Preferably, step 4) is specifically as follows: separating fine slag particles with a particle size less than 3 mm from small slag particles with a particle size less than 20 mm, sending the small slag particles with a particle size of 3-20 mm for salt cooling, obtaining a slag-containing mixed liquid after salt cooling is completed, sending the fine slag particles with a particle size less than 3 mm for air cooling, and obtaining cooled slag after air cooling is completed.

[0118] Preferably, step 5) is specifically as follows: mixing the sintering machine head ash and the high-chlorine dust obtained in step 2) at a mass ratio of 7-10:1 (preferably 8-9:1), and adding the mixture to the slag-containing mixed liquid 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. Coarsely separating the slurry to obtain a fine-particle-containing mixed liquid, then washing the fine-particle-containing mixed liquid with water. Part of the water used for ash washing is ammonia-nitrogen-containing sewage condensate. Filtering to obtain a filter cake and a washing solution; then sending the filter cake to the sintering process.

[0119] Preferably, step 6) is specifically as follows: adding the cooled slag obtained in step 4) to the washing solution 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 a copper-containing material and a reaction waste liquid.

[0120] Preferably, step 7) is specifically as follows: adding a heavy metal removal agent and a hardness removal agent to the reaction waste liquid obtained in step 6), stirring and reacting for 0.5-2 h (preferably 0.8-1.5 h), and then filtering to obtain a filter residue and a supernatant; wherein, the heavy metal removal agent is sodium sulfide or a heavy metal capture agent, and the addition amount is 0.8-8 g / L (preferably 1-5 g / L); the hardness removal agent is sodium carbonate, and the addition amount is 2-15 g / L (preferably 3-10 g / L).

[0121] Preferably, step 8) is specifically as follows: adjusting the pH of the supernatant obtained in step 7) to 11-13 with one or both of sodium hydroxide and potassium hydroxide, and then introducing the supernatant with adjusted pH into an evaporation system. The supernatant passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor in sequence to obtain ammonia-nitrogen-containing sewage condensate, potassium salt, sodium salt, and mother liquor; then using the ammonia-nitrogen-containing sewage condensate for the pelletizing process described in step 1); wherein, the temperature in the triple-effect reactor is 20-60 °C (preferably 30-50 °C), the vacuum degree is -150 to -50 kPa (preferably -100 to -70 kPa), the temperature of the double-effect evaporation is 40-90 °C (preferably 50-80 °C), the vacuum degree is -100 to -30 kPa (preferably -70 to -40 kPa), the temperature of the single-effect evaporation is 70-105 °C (preferably 80-100 °C), the vacuum degree is -50 to -10 kPa (preferably -40 to -15 kPa); collecting the condensate at the steam outlet of the triple-effect reactor, which is the ammonia-nitrogen-containing sewage condensate; preferably, the flow direction of the supernatant is opposite to the flow direction of the steam.

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

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

[0124] Example 1

[0125] A collaborative water washing method for sintering machine head ash and blast furnace bag dust, the method comprising the following steps:

[0126] 1) Mix 84 kg of blast furnace bag dust with 0.84 kg of pulverized coal. After mixing, add sewage condensate containing ammonia nitrogen with an ammonia nitrogen content of 2000 mg / L according to a moisture content of 12% to pelletize, and send the obtained green pellets into a rotary kiln, and roast at 1200 °C in the rotary kiln for 2 h to obtain 63 kg of kiln slag and high-temperature flue gas;

[0127] 2) Introduce the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler, discharge the flue gas after cooling to 160 °C, and then separate it through a bag filter to obtain 3.6 kg of high-chlorine dust and low-temperature flue gas;

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

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

[0130] 5) Mix 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 obtain a slurry, 15.6 L of ammonia-nitrogen-containing sewage condensate, and 77.2 L of recycled water. Conduct hydrocyclone rough separation on the slurry to obtain 20 L of fine-particle-containing mixed liquid, and then conduct water washing and filtration on the fine-particle-containing mixed liquid 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 slag obtained in step 4) to the 80 L of washing liquid obtained in step 5) at a solid-liquid ratio of 2 g / L, react for 0.6 h and then filter to obtain 0.2 kg of copper-containing material and 80 L of reaction waste liquid;

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

[0133] 8) Adjust the pH of the supernatant obtained in step 7) to 12 with sodium hydroxide, and then introduce the 80.5 L of supernatant with adjusted pH 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 24 L of ammonia-nitrogen-containing sewage condensate, 6 kg of potassium chloride, 3.2 kg of sodium chloride, and 8 L of mother liquor. Introduce the ammonia-nitrogen-containing sewage condensate into the pelletizing mixing process described in step 1) at 8.4 L, and the rest is returned to the water washing described in step 5); among them, the temperature in the triple-effect reactor is 40 °C, the vacuum degree is -80 kPa, the temperature of the double-effect evaporation is 60 °C, the vacuum degree is -60 kPa, the temperature of the single-effect evaporation is 90 °C, and the vacuum degree is -30 kPa; collect the condensate at the steam outlet of the triple-effect reactor, which is the ammonia-nitrogen-containing sewage condensate; the flow direction of the supernatant is opposite to the flow direction of the steam;

[0134] 9) Send the low-temperature flue gas obtained in step 2) to a bag filter. After dust removal, obtain 14.4 kg of secondary zinc oxide and clean flue gas;

[0135] 10) Adjust the pH of the 8 L of 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 collaborative water washing method for sintering machine head ash and blast furnace bag dust, the method comprising the following steps:

[0138] 1) Mix 84 kg of blast furnace bag dust with 0.84 kg of pulverized coal. After mixing, add ammonia-nitrogen-containing contaminated condensate with an ammonia-nitrogen content of 2000 mg / L to form pellets according to a moisture content of 12%. Feed the obtained green pellets into a rotary kiln and calcine them at 1200 °C in the rotary kiln for 2 h to obtain 63 kg of kiln slag and high-temperature flue gas;

[0139] 2) Introduce the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler. After the flue gas is cooled to 160 °C, it is discharged. After separation 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 60 kg of large-particle kiln slag with a particle size greater than or equal to 20 mm and 3 kg of small-particle kiln slag with a particle size less than 20 mm. The large-particle kiln slag is sent to the sintering process after water cooling;

[0141] 4) Separate 0.5 kg of fine-particle kiln slag with a particle size less than 3 mm from 3 kg of small-particle kiln slag with a particle size less than 20 mm. Send 2.5 kg of small-particle kiln slag 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-particle kiln slag with a particle size less than 3 mm is sent to air cooling. After air cooling, 0.5 kg of cold slag is obtained;

[0142] 5) Mix 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) according to a solid-liquid ratio of 0.3 kg / L to obtain a slurry, 12 L of ammonia-nitrogen-containing contaminated condensate, and 76 L of recycled water. Carry out hydrocyclone rough separation on the slurry to obtain 19 L of fine-particle-containing mixed liquid, and then carry out water washing and filtration on the fine-particle-containing mixed liquid 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 slag obtained in step 4) to 78.7 L of the washing liquid obtained in step 5) according to a solid-liquid ratio of 2 g / L, react for 0.6 h and then filter to obtain 0.192 kg of copper-containing material and 78.7 L of reaction waste liquid;

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

[0145] 8) Adjust the pH of the supernatant obtained in step 7) to 12 with sodium hydroxide, and then introduce the 79.1 L supernatant with adjusted pH 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 23.2 L of ammonia-nitrogen-containing sewage condensate, 5.8 kg of potassium chloride, 3 kg of sodium chloride, and 7.8 L of mother liquor. Introduce the ammonia-nitrogen-containing sewage condensate into the pelletizing and mixing process described in step 1) at 8.4 L, and return 12 L to the water washing described in step 5); wherein, the temperature in the triple-effect reactor is 40 °C, the vacuum degree is -80 kPa, the temperature of the double-effect evaporation is 60 °C, the vacuum degree is -60 kPa, the temperature of the single-effect evaporation is 90 °C, and the vacuum degree is -30 kPa; collect the condensate at the steam outlet of the triple-effect reactor, which is the ammonia-nitrogen-containing sewage condensate; the flow direction of the supernatant is opposite to the flow direction of the steam;

[0146] 9) Feed the low-temperature flue gas obtained in step 2) into a bag filter, and after dust removal, obtain 14.4 kg of secondary zinc oxide and clean flue gas;

[0147] 10) Adjust the pH of the 7.8 L 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 mixed liquid 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 in the mixing process of step 5) is 0.28 kg / L. 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 in the mixing process of step 5) is 0.4 kg / L. 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 in the mixing process of step 5) is 0.25 kg / L. 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 in the mixing process of step 5) is 0.5 kg / L. 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 in the mixing process of step 5) is 0.2 kg / L. 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 in the mixing process of step 5) is 0.6 kg / L. After precipitation in step 6), 0.158 kg of copper-containing material is obtained.

[0172] Example 15

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

[0174] Example 16

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

[0176] Example 17

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

[0178] Example 18

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

[0180] Example 19

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

Claims

1. A collaborative water washing method for sintering machine head ash and blast furnace bag dust, characterized in that: The method includes the following steps: 1) Mix blast furnace bag dust with fuel and ammonia-containing water, pelletize to obtain green pellets, and then obtain slag and high-temperature flue gas after roasting the green pellets. 2) The high-temperature flue gas obtained in step 1) is cooled and dedusted to obtain high-chlorine dust and low-temperature flue gas. 3) Screen the slag obtained in step 1) to obtain large-particle slag and small-particle slag. 4) Cool the small-particle slag with salt to obtain a slag-containing mixed liquid and / or separate fine-particle slag from the small-particle slag. The fine-particle slag is cooled with air to obtain cold slag. 5) First, mix the high-chlorine dust obtained in step 2) with sintering machine head ash, then add water and the slag-containing mixed liquid obtained in step 4) to prepare a slurry. The slurry is subjected to hydrocyclone rough separation to obtain a fine-particle-containing mixed liquid, and then the fine-particle-containing mixed liquid is washed and filtered to obtain a filter cake and washing liquid. 6) Add the cold slag obtained in step 4) to the washing liquid obtained in step 5) for reaction. After the reaction is completed, a copper-containing material and reaction waste liquid are separated. 7) The reaction waste liquid obtained in step 6) is subjected to heavy metal and hardness removal treatment and then filtered to obtain filter residue and supernatant. 8) First, adjust the supernatant obtained in step 7) to alkaline, and then evaporate and separate salts to obtain ammonia-nitrogen-containing sewage condensate, potassium salt, sodium salt, and mother liquor.

2. The method according to claim 1, wherein: The method further includes: 9) After the low-temperature flue gas obtained in step 2) is dedusted, secondary zinc oxide and clean flue gas are obtained; and / or 10) The mother liquor obtained in step 8) is acidified and atomized and then recycled to step 4) to participate in salt cooling treatment.

3. The method according to claim 2, wherein: The mass ratio of the blast furnace bag dust to the fuel in step 1) is 50-100:1, preferably 75-100:1; and / or The moisture content after mixing the blast furnace bag dust with ammonia-containing water in step 1) is 10-14%, preferably 11-13%; and / or The ammonia-nitrogen concentration in the ammonia-containing water in step 1) is 1000-3000 mg / L, preferably 1500-2500 mg / L; and / or The roasting temperature in step 1) is 1100-1500 °C, preferably 1100-1300 °C; and / or The roasting time in step 1) is 1.5-3 h, preferably 2-2.5 h; and / or The fuel in step 1) is one or both of pulverized coal and charcoal, preferably pulverized coal.

4. The method according to claim 2 or 3, characterized in that: The cooling in step 2) is to cool the high-temperature flue gas to 150-200 °C, preferably 160-180 °C; and / or The cooling in step 2) is to cool the high-temperature flue gas by using a waste heat boiler and a surface cooler; and / or The dust removal treatment in step 2) is to remove dust from the cooled high-temperature flue gas by using a bag filter.

5. The method according to any one of claims 2 to 4, characterized in that: The particle size of the large-particle slag in step 3) is greater than 20 mm, preferably 20-40 mm; and / or The particle size of the small-particle slag in step 3) is less than 20 mm, preferably 3-20 mm; and / or The particle size of the fine-particle slag in step 4) is less than 3 mm, preferably 0-3 mm; and / or Step 3) further includes: 31) After the large-particle slag obtained in step 3) is cooled with water, it is sent to the sintering process.

6. The method according to any one of claims 2-5, characterized in that: The mass ratio of the sintering machine head ash to the high-chlorine dust in step 5) is 7-10:1, preferably 8-9:1; and / or The high-chlorine dust, sintering machine head ash, water, and slag-containing mixed liquid described in step 5) are used to obtain a slurry. The slurry is subjected to hydrocyclone rough separation to obtain a fine-particle-containing mixed liquid, and then the fine-particle-containing mixed liquid is washed with water. During the mixing process, the solid-liquid ratio of the slurry is 0.25 to 0.5 kg / L, preferably 0.28 to 0.4 kg / L; and / or The solid-liquid ratio of the high-chlorine dust, sintering machine head ash, and slag-containing mixed liquid described in step 5) is 2 to 6 kg / L, preferably 3 to 5 kg / L; and / or The hydrocyclone process described in step 5) uses a hydrocyclone separator; and / or Step 5) further includes: 51) sending the obtained filter cake to the sintering process; and / or The solid-liquid ratio of the cold slag and the washing liquid described in step 6) is 1 to 5 g / L, preferably 2 to 3 g / L; and / or The reaction time described in step 6) is 0.5 to 1 h, preferably 0.6 to 0.8 h.

7. The method according to any one of claims 2-6, characterized in that: The removal of heavy metals and hardness in step 7) is: adding a heavy metal removal agent and a hardness removal agent to the reaction waste liquid; Preferably, the heavy metal removal agent is sodium sulfide or a heavy metal capture agent, and the addition amount is 0.8 to 8 g / L, preferably 1 to 5 g / L; and / or The hardness removal agent is sodium carbonate, and the addition amount is 2 to 15 g / L, preferably 3 to 10 g / L; Preferably, the reaction time for the removal of heavy metals and hardness is 0.5 to 2 h, preferably 0.8 to 1.5 h.

8. The method according to any one of claims 2-7, characterized in that: Adjusting the supernatant to alkaline in step 8) is: adjusting the pH of the supernatant to 11 to 13 using an alkaline solution; preferably, the alkaline solution is one or two of sodium hydroxide and potassium hydroxide; and / or The evaporation and salt separation in step 8) is multi-stage countercurrent evaporation, preferably three-stage countercurrent evaporation; and / or Step 8) further includes: 81) adding the ammonia-nitrogen-containing sewage condensate obtained in step 8) as ammonia-containing wastewater to the mixed pelletizing process described in step 1) and / or as ash washing water to the water washing process of the fine-particle-containing mixed liquid described in step 5).

9. The method according to any one of claims 2-8, characterized in that: The acidification in step 10) is to adjust the pH of the mother liquor to 2 to 7 using concentrated sulfuric acid, preferably 3 to 6.

10. The method according to any one of claims 2-9, characterized in that: Step 1) specifically is: mixing blast furnace bag dust and fuel at a mass ratio of 50 to 100:1 (preferably 75 to 100:1), after mixing, adding water with a moisture content of 10 to 14% (preferably 11 to 13%) to pelletize with ammonia-containing water with an ammonia-nitrogen content of 1000 to 3000 mg / L (preferably 1500 to 2500 mg / L), sending the obtained green pellets into a rotary kiln, and roasting in the rotary kiln at 1100 to 1500 °C (preferably 1100 to 1300 °C) for 1.5 to 3 h (preferably 2 to 2.5 h) to obtain kiln slag and high-temperature flue gas; and / or Step 2) specifically is: introducing the high-temperature flue gas obtained in step 1) into a waste heat boiler and a surface cooler, cooling it to 150 to 200 °C (preferably 160 to 180 °C), and then separating the flue gas through a bag filter to obtain high-chlorine dust and low-temperature flue gas; and / or Step 3) specifically includes: separating the 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; among them, the large particle kiln slag is sent to the sintering process after water cooling; and / or Step 4) specifically includes: separating fine particle kiln slag with a particle size less than 3 mm from the small particle kiln slag with a particle size less than 20 mm, sending the small particle kiln slag with a particle size of 3 - 20 mm for salt cooling, and obtaining a slag-containing mixed liquid after salt cooling, sending the fine particle kiln slag with a particle size less than 3 mm for air cooling, and obtaining cold slag after air cooling; and / or Step 5) specifically includes: mixing the sintering machine head ash and the high-chlorine dust obtained in step 2) according to a mass ratio of 7 - 10:1 (preferably 8 - 9:1), and adding to the slag-containing mixed liquid 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. Coarsely separating the slurry to obtain a fine particle-containing mixed liquid, then washing the fine particle-containing mixed liquid. Part of the water for ash washing is ammonia-nitrogen-containing sewage condensate, filtering to obtain a filter cake and a washing liquid; then sending the filter cake to the sintering process; and / or Step 6) specifically includes: 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 a copper-containing material and a reaction waste liquid; and / or Step 7) specifically includes: adding a heavy metal removal agent and a hardness removal agent to the reaction waste liquid obtained in step 6), stirring and reacting for 0.5 - 2 h (preferably 0.8 - 1.5 h), and then filtering to obtain a filter residue and a supernatant; among them, the heavy metal removal agent is sodium sulfide or a heavy metal capture agent, and the addition amount is 0.8 - 8 g / L (preferably 1 - 5 g / L); the hardness removal agent is sodium carbonate, and the addition amount is 2 - 15 g / L (preferably 3 - 10 g / L); and / or Step 8) specifically includes: adjusting the pH of the supernatant obtained in step 7) to 11 - 13 with one or both of sodium hydroxide and potassium hydroxide, and then introducing the supernatant with adjusted pH into an evaporation system. The supernatant passes through a triple-effect reactor, a double-effect reactor, and a single-effect reactor in sequence to obtain ammonia-nitrogen-containing sewage condensate, potassium salt, sodium salt, and mother liquor; then using the ammonia-nitrogen-containing sewage condensate for the mixed pelletizing process described in step 1); among them, the temperature in the triple-effect reactor is 20 - 60 °C (preferably 30 - 50 °C), the vacuum degree is -150 - -50 kPa (preferably -100 - -70 kPa), the temperature of the double-effect evaporation is 40 - 90 °C (preferably 50 - 80 °C), the vacuum degree is -100 - -30 kPa (preferably -70 - -40 kPa), the temperature of the single-effect evaporation is 70 - 105 °C (preferably 80 - 100 °C), the vacuum degree is -50 - -10 kPa (preferably -40 - -15 kPa); collecting the condensate at the steam outlet of the triple-effect reactor, which is the ammonia-nitrogen-containing sewage condensate; preferably, the flow direction of the supernatant is opposite to the flow direction of the steam; and / or The specific operation of step 9) is as follows: 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 The specific operation of step 10) is as follows: adjusting the pH of the mother liquor obtained in step 8) to 2-7 (preferably 3-6) with concentrated sulfuric acid, and then after atomization, adding it as a high-salt cooling liquid to the salt cooling process described in step 4).

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