Harmless treatment method and system for corrosive hazardous waste

Abstract

The invention relates to a harmless treatment method and system for corrosive hazardous wastes, and the system comprises a flue gas chlorine element removal and analysis device which comprises a sintering flue gas inlet pipeline A, a sintering flue gas outlet pipeline B, a branch I gas inlet pipeline C and a branch II gas inlet pipeline D, the sintering flue gas inlet pipeline A is communicated with the branch I gas inlet pipeline C and the branch II gas inlet pipeline D, and the output end of the branch I gas inlet pipeline C and the output end of the branch II gas inlet pipeline D are communicated with the sintering flue gas outlet pipeline B. The method has the advantages that the acid mud and the alkali mud generated by the cold rolling system are co-processed through the sintering process, the proportionality coefficient of the chlorine element entering the flue gas in the sintering raw material is online absorbed, analyzed and calculated, the addition amount of the acid mud and the alkali mud is dynamically controlled in real time, and the situation that the quality of sintered ore is affected due to improper addition amount of the acid mud and the alkali mud is avoided; and the smooth operation of the blast furnace and the service life of a gas pipe network are influenced.

Description

Technical Field

[0001] The present invention relates to the field of comprehensive utilization of wastes, and in particular to a method and system for harmlessly treating corrosive hazardous wastes. Background Art

[0002] Iron and steel enterprises use their own furnaces to harmlessly treat acid mud and alkali mud, so that part of the chloride salts and residual hydrochloric acid in the waste enters the atmosphere with the flue gas, causing serious secondary pollution to the environment. Studies have found that when the chloride salt and residual hydrochloric acid content in the sintering raw materials is low, almost all of the chloride salts and residual hydrochloric acid in the raw materials enter the flue gas after sintering, and the chloride salt and residual hydrochloric acid content entering the sintered ore products is extremely low, which has no effect on product quality and subsequent process flow; but when the chloride salt and residual hydrochloric acid content in the sintering raw materials is higher than the critical value under a certain condition, after sintering, the proportion of chloride salts and residual hydrochloric acid in the raw materials entering the sintered ore increases sharply, and a large amount of chloride salts and residual hydrochloric acid enter the sintered ore, which seriously affects the smooth operation of the blast furnace and causes acid corrosion in the blast furnace system and gas pipeline network. Because the critical value is not fixed under different sintering raw materials and process parameters, and the composition of acid mud and alkali mud is not constant, and the composition of acid mud and alkali mud produced in different time periods fluctuates greatly, the amount of acid mud and alkali mud added in the sintering process cannot be fixed. The existence of these factors increases the difficulty of treatment. There is currently no better method to control the amount of acid mud and alkali mud added in the sintering process to reduce the impact on production.

[0003] On the other hand, acid mud and alkali mud will release a large amount of chloride salt and residual hydrochloric acid during the sintering process, which promotes the formation and emission of dioxins. The presence of residual hydrochloric acid will corrode the flue gas pipelines and equipment on the one hand, and on the other hand, the presence of residual hydrochloric acid will have a negative impact on the flue gas desulfurization process, resulting in reduced desulfurization efficiency and other consequences, thus causing environmental pollution. There is currently no good economic and reasonable method for removing chloride salt and residual hydrochloric acid in sintering flue gas.

[0004] Wu Yanmei published an article entitled "The Harmless Treatment Practice of Chromium Slag in Sintering Production", which introduced the production practice of Sichuan Dagang in treating chromium-containing waste slag during sintering. Wang Hongjun et al. published an article entitled "The Application Practice of Chromium Slag in Jiugang Sintering Production", which introduced Jiugang's treatment method of using chromium slag as a sintering auxiliary material in the sintering system. Both articles are about the application of chromium-containing solid waste in the sintering system, but their technical research content only considers the impact of chromium on the output and quality of sintering production. The existence form and final destination of chromium in the process of sintering treatment of chromium-containing waste are not involved and considered, ignoring the impact of chromium-containing waste on the environment. As hazardous waste, it needs to be centrally treated harmlessly, and the method of simply treating it as a sintering auxiliary material without considering environmental factors may not only fail to achieve the harmless treatment of toxic waste, but also cause the spread of hazardous waste through sintering flue gas emissions.

[0005] The application number is CN201921036591.2, and the patent name is "Tail Gas Treatment Equipment in the Process of Disposal of Chromium-Containing Heavy Metal Hazardous Waste". It includes a dust purification device, an acid gas purification tank, and a sludge settling tank. The dust purification device can mix the steam generated during water quenching with the flue gas, and use the condensation of the steam to settle the dust in the flue gas. The dust-removed flue gas is sent into the acid gas purification tank, below the liquid level, so that the acid gas in the flue gas fully reacts with the solution, thereby purifying the acid gas. When the equipment is running, a large amount of steam is required to participate in condensation, which consumes a lot of resources and energy, and has high operating costs. The effect of steam condensation in purifying chromium-containing dust particles is limited, and the removal rate of chromium-containing dust is low.

[0006] Application number CN202010515460.3, patent name "A method and system for preparing sintering raw materials using cold-rolled alkali mud", discloses a method and system for preparing sintering raw materials using cold-rolled alkali mud, including the following steps: turning on the induced draft fan to keep the inside of the two-stage double-axis digester in a slightly negative pressure state; continuously and quantitatively inputting the cold-rolled alkali mud, quicklime and dust removal ash into the two-stage double-axis digester through a double-axis screw conveyor, a first single-axis screw conveyor and a second single-axis screw conveyor respectively to mix to obtain a mixture; using a closed belt conveyor to convey the mixture to a batching bin; using a disc feeder to convey the mixture in the batching bin to a rotary mixer, and mixing with preset raw materials to form a sintering raw material. The advantages of this application are: (1) it realizes the continuous closed conveying and quantitative addition of cold-rolled alkali mud; (2) the closed material conveying and pretreatment technology is environmentally friendly; (3) the precise quantitative measurement of cold-rolled alkali mud makes it easy to control the moisture content after mixing within a stable range. This method has certain drawbacks: First, it does not take into account that the composition of acid sludge and alkali sludge is not constant, but fluctuates significantly. Second, it does not take into account that when the amount of acid sludge and alkali sludge added reaches a critical value under certain conditions, the proportion of chlorine and residual acid entering the sintered ore will increase sharply, so it is not feasible to rely solely on quantitative addition. Third, this method does not take into account the problem that some toxic and harmful substances will overflow with the flue gas during the treatment of acid sludge and alkali sludge, causing secondary pollution.

[0007] Application number CN201310398285.4, patent name "A method for producing sintered ore using waste acid mud", discloses a method for producing sintered ore using waste acid mud, wherein the waste acid mud is roasted at low temperature for 3-4 hours in a rotary kiln using waste gas at a temperature of 200-300°C in a steel plant, water and free hydrochloric acid in the waste acid mud are removed, hydrochloric acid vapor is formed, and iron-rich residue is obtained; the roasted dry waste acid mud is crushed to less than 8 mm by a crusher and enters a sintering system, and the crushed dry waste acid mud is used as an iron material for batching, and the dry waste acid mud accounts for 3%-8% of the mass percentage of the sintered iron material. After mixing, watering, digestion, and sintering, high-quality sintered ore is produced; the hydrochloric acid vapor is pumped into a spray tower (6) by an exhaust fan (7), and the hydrochloric acid liquid is recovered by spraying. The metallurgical properties of the sintered ore are improved. This method also fails to take into account the secondary environmental pollution caused during the treatment process, as well as the problem of increased chlorine content and residual acid in sintered ore products due to improper addition of acid sludge and alkali sludge.

[0008] Application number CN201811373734.9, patent name "double-drum rotary kiln harmless disposal of chromium-containing sludge flue gas purification system", including a tilted double-drum rotary kiln, which effectively solves the dust, acid gas, nitrogen oxide waste gas treatment process in the chromium-containing sludge treatment process, so that its emissions meet the requirements of the "Hazardous Waste Incineration Pollution Control Standard" (GB18484-2001). The device passes the flue gas through the settling chamber and cyclone dust collector in sequence, and then washes it through the first water film dust removal and desulfurization spray tower, and then through the second water film dust removal and desulfurization spray tower, and then through the third water film dust removal and desulfurization spray tower. The whole system has a complex structure, and through sedimentation, cyclone dust removal, and three-stage spraying, the equipment cost and operating cost are high. In the selection of reagents, there is no targeted capture of chromium-containing dust, and chromium-containing fine dust cannot be completely captured.

[0009] The application number is CN200810058792.2, and the patent name is "Method for determining heavy metal elements in cigarette smoke using a smoke capture and absorption device". The smoke capture and absorption device includes an outer sleeve (1), an inner sleeve (2) and a sealing plug (3). The outer sleeve (1) is provided with an inlet (7) and an outlet (8). The outer sleeve (1), the inner sleeve (2) and the sealing plug (3) are sealed and matched in sequence. An upper sieve plate (6) and a lower sieve plate (4) are provided in the inner sleeve (2), and a buffer filler (5) is filled between the two sieve plates. In this method, the residence time and absorption time of smoke in the capture agent are slightly prolonged by the combined action of the upper sieve plate, the lower sieve plate, the buffer filler and other structures. In addition, the smoke is dispersed by the sieve plate and buffered by the buffer filler, and the reaction surface area of ​​smoke absorption is increased, so that the smoke components are more fully absorbed. However, the buffer filler can only play a buffering role. Its gap is too large to filter the tiny dust particles in the gas. The absorption of dust particles depends only on the short-term contact reaction between the collector and the flue gas, resulting in a low dust capture rate. In addition, the device can only absorb gases with small flow rates and low flue gas flow rates. The impact generated by the large flow rate and high flow rate of sintering flue gas passing into the device will disperse the buffer filler and even cause the collector to splash. In addition, the contact reaction time between the flue gas with a faster flow rate and the collector is shorter, resulting in insufficient absorption.

[0010] The application number is CN201921879172.5, and the patent name is "A Asphalt Smoke Absorption Device". The asphalt smoke absorption device has a structure including a cylinder, a resistance layer, an ozone layer, an ultraviolet lamp, a spray covering layer, a fan, and an exhaust port. It is characterized in that: a multi-layer filter plate is arranged at the bottom of the cylinder, the first layer of the multi-layer filter plate is provided with a screen made of asbestos mesh, the second layer is a material of activated carbon honeycomb holes, and the third layer is a screen plate covered with quicklime, and the height between two adjacent absorption layers is 300mm-500mm. The central cross-sectional position of the cylinder is the resistance layer, the spray covering layer, and the return smoke fan air collection port from top to bottom, and the spray covering layer is added with an organic flux that can absorb asphalt particles. The device uses an organic flux to absorb particulate matter in the asphalt smoke, and through the joint action of the resistance layer, the ozone layer, and the ultraviolet lamp, the asphalt smoke and oxygen are further reacted at high temperature to achieve a good absorption effect. However, the use of this device has certain limitations and disadvantages: first, the device has a complex structure and high cost. The material of the activated carbon honeycomb holes will become invalid after use and needs to be replaced regularly. The resources and energy costs consumed by the operation of the ozone layer and the resistance layer are also high, which significantly increases the operating cost of the equipment; second, in the several layers of filtering structure of the device, the asbestos mesh has limited filtering and intercepting effect on tiny dust in the flue gas, and the screen plate covered with quicklime only absorbs some acidic gases in the flue gas, and the absorption is not complete enough. The spraying of organic flux is to spray the spray liquid through tiny water droplets, and its collision with small asphalt particles in the flue gas is random, so the spraying absorption effect is poor. The combined effect of the resistance layer, ozone layer, and ultraviolet lamp only has a certain effect on organic particles in asphalt flue gas, and its effect is also very limited.

[0011] The application number is CN202021710826.4, and the patent name is "A petrochemical flue gas absorption device", which is characterized by: including an absorption tower, a scrubbing part, a chemical absorption part and a water vapor recovery part. The scrubbing part is arranged at the bottom of the absorption tower, the chemical absorption part is arranged in the middle of the absorption tower, and the water vapor recovery part is arranged at the upper part of the absorption tower. The water vapor recovery part includes a water vapor baffle, and the water vapor baffle includes a water vapor baffle groove and a water vapor recovery groove. A cold air channel is provided at the top of the water vapor baffle groove, and a water outlet groove is provided at the bottom of the water vapor recovery groove. A heat conduction plate is provided on the cold air channel, a water collecting plate is provided on the water outlet groove, and a water outlet is provided at the bottom of the water outlet groove. After the flue gas is passed into the bottom of the absorption tower, it is scrubbed and cooled at the bottom of the absorption tower, and then chemically absorbed by the acid gas, and finally the water vapor is recovered. The device effectively solves the problem of catalysts and water in flue gas after treatment in conventional absorption towers, but it still has certain limitations and disadvantages: when the flue gas passes through the scrubbing part of the device, it usually moves upward rapidly in the form of bubbles, and the reaction time between the flue gas and the absorption liquid is limited and the contact area is small, resulting in insufficient absorption of dust particles in the flue gas, and the chemical absorption and water vapor absorption parts cannot achieve the purpose of absorbing dust particles in the flue gas.

[0012] Application number CN201410223759.6, patent name "A method for detecting chromium, nickel, arsenic, selenium, cadmium and lead in cigarette sidestream smoke", characterized by: using a fishtail cover in series with a quartz fiber filter to collect cigarette sidestream smoke particulate matter, three-stage nitric acid solution in series to collect sidestream smoke gaseous matter, microwave digestion method to digest the sample, and inductively coupled plasma mass spectrometry to detect the content of chromium, nickel, arsenic, selenium, cadmium and lead in the particulate matter and gaseous matter samples. This method absorbs toxic substances in the smoke separately and then detects them. This method requires the particulate matter and gaseous matter to be processed separately, which undergoes a series of processes such as elution, extraction, digestion, ultrasonic vibration, heating and concentration. The operation is complicated, time-consuming and costly. More importantly, the method of collecting particulate matter through a quartz fiber filter cannot completely absorb the particulate matter in the smoke, and some particles with extremely small particle sizes cannot be captured.

[0013] Among the existing methods for harmless disposal of corrosive hazardous wastes in China, there is no relatively economical and reasonable treatment method that can effectively avoid the residue of chloride salts and residual hydrochloric acid in sintered ore and prevent secondary environmental pollution. Summary of the invention

[0014] The purpose of the present invention is to provide a method and system for harmlessly treating corrosive hazardous wastes. The method can achieve the harmless treatment of acid sludge and alkali sludge in the cold rolling system through the sintering process, and avoid the excessive residue of chloride salts and residual hydrochloric acid brought in by the acid sludge and alkali sludge in the sintered ore. The method does not cause secondary pollution, not only saves high hazardous waste treatment costs, but also makes full use of the iron resources in the waste, creating considerable economic and environmental benefits.

[0015] To achieve the above object, the present invention is implemented through the following technical solutions:

[0016] A method for harmless treatment of corrosive hazardous wastes, specifically comprising:

[0017] S1. preparing neutralized ash;

[0018] S2, batching and premixing the neutralized ash with other dust and mud to obtain a dust and mud mixture, wherein the neutralized ash accounts for 1% to 7% of the total dust and mud mixture;

[0019] S3, premixing the dust-sludge mixture with the iron-containing material to obtain a premix, wherein the dust-sludge mixture accounts for 14% to 17% of the total premix;

[0020] S4, the premixed material is mixed with the fuel and the flux again, and the mixture is mixed once and granulated twice to obtain a sintering mixture;

[0021] S5. Distribute, ignite and sinter the sintering mixture. During the sintering process, the sintering flue gas generated by the sintering mixture is passed through a flue gas chlorine removal and analysis device for treatment;

[0022] S6. Calculate the ratio coefficient of chlorine in the sintering raw materials entering the flue gas. The formula is as follows:

[0023]

[0024] In the formula, ω represents the ratio coefficient of chlorine element in sintering raw materials entering flue gas, Q represents the flow rate of sintering flue gas generated by the mixed material in this section during the sintering process, in cubic meters, and W represents the chloride ion concentration in the sintering flue gas absorption liquid, in mg / m 3 , C represents the mass percentage of chlorine in the sintering mixture, in %, and M represents the mass of the sintering mixture, in tons;

[0025] S7. Determine the amount of chlorine added to the sintering raw materials according to the value of the ratio coefficient ω of the chlorine element in the sintering raw materials entering the flue gas.

[0026] In S1, neutralized ash is prepared in the following steps:

[0027] S11, mixing cold rolling acid mud and cold rolling alkali mud in a ratio of 8:1 to 10:1 to make the materials undergo a neutralization reaction, and the mixed materials are neutralized mud;

[0028] S12, drying the neutralized mud at a temperature of 100-110° C. until the moisture content is less than 1%;

[0029] S13, drying process, recovering the hydrogen chloride volatilized in the neutralization mud;

[0030] S14, crushing the dried material;

[0031] S15: More than 90% of the crushed materials with a particle size less than 1 mm are neutral ash.

[0032] In S2, other dust and mud include blast furnace dust, gas mud, sintering machine head dust, converter mud, steelmaking dust, and hot-rolled iron mud; in S3, iron-containing materials include rich ore powder and concentrate.

[0033] In S5, the content is as follows:

[0034] Before laying, the sintering mixture is weighed and the chlorine content is analyzed by mass percentage to obtain the total mass of chlorine brought into the sintering raw materials;

[0035] The sintering mixture is distributed, the sintering trolleys are numbered, the starting and ending positions of the trolleys corresponding to the distribution process of the weighed sintering mixture are recorded, and ignition and sintering are performed;

[0036] During the sintering process, the flow rate of the sintering flue gas generated by the sintering mixture of this section is measured, and then the flue gas is passed into the flue gas chlorine removal and analysis device for treatment, and the total chlorine content of the absorption liquid is analyzed to obtain the total mass of chlorine in the sintering flue gas generated by this section of the sintering mixture.

[0037] In S7, the content is as follows:

[0038] When the ratio coefficient ω of chlorine in the sintering raw materials entering the flue gas is ≥0.965, increase the addition ratio of cold rolling acid mud and cold rolling alkali mud, or continue to maintain the addition amount parameter;

[0039] When the ratio coefficient ω of chlorine element in the sintering raw materials entering the flue gas is less than 0.965, it is necessary to immediately reduce the addition ratio of cold rolling acid mud and cold rolling alkali mud in the sintering raw materials.

[0040] A harmless treatment system for corrosive hazardous wastes includes a flue gas chlorine removal and analysis device, the flue gas chlorine removal and analysis device includes a sintering flue gas inlet pipe A, a sintering flue gas outlet pipe B, a branch I inlet pipe C, and a branch II inlet pipe D, the sintering flue gas inlet pipe A is connected with the branch I inlet pipe C and the branch II inlet pipe D respectively, and the output end of the branch I inlet pipe C and the output end of the branch II inlet pipe D are connected with the sintering flue gas outlet pipe B.

[0041] The internal structures of branch I air inlet pipe C and branch II air inlet pipe D are the same, both including: a branch air inlet pipe, a branch air outlet pipe, and an absorption liquid tank. The branch air inlet pipe is connected to the sintering flue gas inlet pipe A, the branch air outlet pipe is connected to the sintering flue gas outlet pipe B, the branch air inlet pipe is connected to the branch air outlet pipe, and the lower end of the branch air outlet pipe is connected to the absorption liquid tank.

[0042] A smoke filter is fixedly connected to the connection point between the branch air inlet pipe and the branch air outlet pipe. The smoke filter and the transverse section of the branch air inlet pipe are arranged perpendicular to each other. The bottom end of the smoke filter extends into the absorption liquid in the absorption liquid tank. A submersible pump is arranged in the absorption liquid tank. The submersible pump is connected to a water pipe. A spray gun is arranged at the front end of the water pipe. The submersible pump presses water out of the spray gun through the water pipe. The water pipe is arranged between the branch air inlet pipe and the smoke filter.

[0043] The spray gun is an umbrella-shaped spray gun, and a potentiometric titrator is arranged inside the absorption liquid tank, and the potentiometric titrator is used to measure the chloride ion concentration in the absorption liquid.

[0044] The absorption liquid is a mixed solution of NaOH and Ca(OH)2, in which the mass percentage concentration of NaOH is 3% to 6.5%, and the mass percentage concentration of Ca(OH)2 is 1.5% to 3%. The liquid flow rate of each spray gun is adjusted to 600 to 1200 ml / min by a submersible pump.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The sintering process is used in a coordinated manner to achieve the compliance disposal of hazardous waste, eliminate its pollution and harm to the environment, and save a lot of disposal costs and investment costs;

[0047] 2. The acid sludge and alkali sludge generated by the cold rolling system are processed in coordination with the sintering process. The proportion coefficient of chlorine in the sintering raw materials entering the flue gas is absorbed and analyzed online to dynamically and in real time control the amount of acid sludge and alkali sludge added, thus avoiding the impact of improper addition of acid sludge and alkali sludge on the quality of sintered ore, thereby affecting the smooth operation of the blast furnace and the life of the gas pipeline network;

[0048] 3. A low-cost and high-efficiency flue gas dechlorination wet process is adopted to solve the secondary pollution caused by the acid sludge and alkali sludge treatment process, improve the chlorine removal rate, achieve a removal rate far higher than the existing wet process, and reduce costs;

[0049] 4. The sintering process is used to dispose of corrosive hazardous wastes, which not only achieves the harmless disposal of acid sludge and alkali sludge and reduces their harm to the environment, but also rationally utilizes the iron resources in the waste and creates considerable economic benefits;

[0050] 5. An efficient and low-cost flue gas chlorine removal and online analysis method is adopted. The absorption liquid is sprayed into small mist droplets through an umbrella-shaped spray gun in the flue gas pipeline to fully react with the flue gas in the pipeline. At the same time, the umbrella-shaped spray gun also sprays the absorption liquid evenly onto the microporous flue gas filter. The tiny mesh is filled with absorption liquid. When the gas passes through the filter, the chlorine element is further fully intercepted. The intercepted chlorine element enters the absorption liquid tank below under the flushing action of the umbrella-shaped spray gun, and finally the analysis and detection of the chlorine element is realized through the potentiometric titration device. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a flow chart for harmless treatment of acid sludge and alkali sludge in cold rolling system.

[0052] Figure 2 It is a schematic diagram of the structure of a gaseous chlorine element removal and analysis device.

[0053] Figure 3 It is a schematic diagram of the internal structure of a branch of the gas chlorine element removal and analysis device.

[0054] In the figure: 1-branch air inlet pipe 2-branch air outlet pipe 3-submersible pump 4-spray gun 5-smoke filter 6-potentiometric titration device 7-branch absorption liquid inlet 8-branch absorption liquid outlet 9-absorption liquid tank. DETAILED DESCRIPTION

[0055] The present invention is described in detail below in conjunction with the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0056] A method and system for harmless treatment of corrosive hazardous wastes, see Figure 1 , the specific plan is as follows:

[0057] S1. Use a mixer to mix cold-rolled acid mud and cold-rolled alkali mud in a ratio of 8:1 to 10:1 to make the materials neutralize. The mixed material is neutralized mud. Since the acid is excessive and acidic, the neutralized mud is dried at 100-110℃ until the moisture content is less than 1%. The hydrogen chloride volatilized in the neutralized mud is recycled during the drying process. After the dried material is crushed, the particle size of less than 1mm must account for more than 90%, which is neutralized ash.

[0058] S2. The neutralized ash is batched and pre-mixed with other dust muds (including blast furnace dust removal ash, gas mud, sintering machine head dust removal ash, converter mud, steelmaking dust removal ash, hot rolling iron mud) to obtain a dust mud mixture, wherein the neutralized ash accounts for 1% to 7% of the total dust mud mixture.

[0059] S3. The dust-sludge mixture is pre-mixed with rich ore powder, concentrate and various iron-containing materials to obtain a premix. In this process, the dust-sludge mixture accounts for 14% to 17% of the total premix.

[0060] S4, the premixed material is mixed again with the fuel and the flux, and the mixture is mixed once and granulated twice to obtain a sintering mixture.

[0061] S5. Before spreading, the sintering mixture is weighed (recorded as M, unit t), and the mass percentage content of chlorine element is analyzed (recorded as C, unit %), and the sintering mixture is spread. The sintering trolleys are numbered, and the starting position and the end position of the trolley corresponding to the spreading process of the weighed sintering mixture are recorded, and ignition and sintering are performed; during the sintering process, the flow rate of the sintering flue gas generated by the section of the mixture is measured (recorded as Q, unit m3), and then the flue gas chlorine element removal and analysis device (device structure see Figure 2 , Figure 3 ) and the absorption liquid was analyzed for total chlorine content (recorded as W, unit mg / m 3 ), wherein the absorption liquid added to the flue gas chlorine removal and analysis device is a mixed solution of NaOH and Ca(OH)2, the mass percentage concentration of NaOH in the mixed solution is 3% to 6.5%, and the mass percentage concentration of Ca(OH)2 is 1.5% to 3%; the liquid flow rate of each spray gun is adjusted to 600 to 1200 ml / min by a circulating water pump; the treated flue gas is successively subjected to gravity dust removal, drying, electrostatic precipitator, desulfurization and denitrification, and finally achieves standard emission.

[0062] S6. Calculate the ratio coefficient ω of chlorine in the sintering raw materials entering the flue gas. The formula is as follows:

[0063]

[0064] S7. Determine whether the chlorine in the raw material is excessively added according to the coefficient ω value. When the ω value is ≥0.965, the addition ratio of acid sludge and alkali sludge can be appropriately increased according to the processing volume, or the addition parameter can be maintained; when the ω value is <0.965, the addition ratio of acid sludge and alkali sludge in the sintering raw material needs to be reduced immediately. The parameter ω uses the critical point of 0.965 as the basis for determining whether the corrosive element chlorine in the sintering raw material is excessively added.

[0065] See Figure 2 , Figure 3 A harmless treatment system for corrosive hazardous wastes includes a flue gas chlorine removal and analysis device, the flue gas chlorine removal and analysis device includes a sintering flue gas inlet pipe A, a sintering flue gas outlet pipe B, a branch I inlet pipe C, a branch II inlet pipe D, a pipe switch valve E, and a pipe switch valve F. The sintering flue gas inlet pipe A is connected to the branch I inlet pipe C and the branch II inlet pipe D respectively, and the output end of the branch I inlet pipe C and the output end of the branch II inlet pipe D are connected to the sintering flue gas outlet pipe B. The internal structures of the branch I air inlet pipe C and the branch II air inlet pipe D are the same, and both include: a branch air inlet pipe 1, a branch air outlet pipe 2, and an absorption liquid tank 9. The branch air inlet pipe 1 is connected to the sintering flue gas air inlet pipe A, and a pipe switch valve E / pipe switch valve F is provided at the entrance of the branch air inlet pipe 1. The branch air outlet pipe 2 is connected to the sintering flue gas outlet pipe B, the branch air inlet pipe 1 is connected to the branch air outlet pipe 2, and the lower end of the branch air outlet pipe 2 is connected to the absorption liquid tank 9; the branch air inlet pipe 1 is connected to the branch air outlet pipe The connection point connected with the branch air inlet pipe 2 is fixedly connected with a flue gas filter 5, and the flue gas filter 5 and the transverse section of the branch air inlet pipe 1 are arranged perpendicular to each other. The bottom end of the flue gas filter 5 extends into the absorption liquid in the absorption liquid tank 9. The flue gas filter 5 is used to absorb and intercept the chlorine element in the flue gas after being moistened with the absorption liquid. A submersible pump 33 is arranged in the absorption liquid tank 9, and the submersible pump 33 is connected to the water pipe. A spray gun 4 is arranged at the front end of the water pipe. The submersible pump 3 presses water out of the spray gun 4 through the water pipe. The water pipe is arranged between the branch air inlet pipe 1 and the flue gas filter 5. The spray gun 4 is an umbrella-shaped spray gun 4, and a potentiometric titrator 6 is arranged inside the absorption liquid tank 9. The potentiometric titrator 6 is used to measure the chloride ion concentration in the absorption liquid. A branch absorption liquid inlet 7 is provided at the upper end of the absorption liquid tank 9, and a branch absorption liquid outlet 8 is provided at the lower end of the absorption liquid tank 9. The absorption liquid inlet 7 is used to add absorption liquid into the absorption liquid tank 9, and the absorption liquid outlet 8 is used to discharge the waste absorption liquid after the absorption is completed from the absorption liquid tank 9; the absorption liquid adopts a mixed solution of NaOH and Ca(OH)2, the mass percentage concentration of NaOH in the mixed solution is 3% to 6.5%, and the mass percentage concentration of Ca(OH)2 is 1.5% to 3%, and the liquid flow rate of each spray gun 4 is adjusted to 600 to 1200 ml / min by the submersible pump 3.

[0066] Working process of flue gas chlorine removal and analysis device:

[0067] The pre-prepared absorption liquid is added to the absorption liquid tank 9 through the branch absorption liquid inlet port ⑦ of the branch I air inlet pipe C and the branch II air inlet pipe D, respectively, so that the liquid level is higher than the bottom of the flue gas filter 5; the flue gas is passed into the sintering flue gas inlet pipe A, the branch I pipe switch valve E is opened, and the branch II pipe switch valve F is closed, so that the flue gas passes through the branch I air inlet pipe C, and the circulating water pump and the circulating water umbrella-shaped spray gun 4 in the branch I air inlet pipe C are opened at the same time, so that the flue gas and the absorption liquid react fully and then are discharged through the sintering flue gas outlet pipe B. After all the flue gas to be tested in this section passes through, the total flow rate of the flue gas passing through the process is recorded, and the chloride ion concentration of the absorption liquid in the branch I air inlet pipe C is determined by the potentiometric titration device 6; the process data is brought into the S6 formula to calculate the proportional coefficient ω, and then the value of the proportional coefficient ω is used to control and adjust the addition ratio of cold rolling acid mud and cold rolling alkali mud during the sintering process.

[0068] The above process completes the chlorine removal and analysis of a section of sintering flue gas. Since sintering production is carried out continuously, it is generally necessary to continue the chlorine removal and analysis of the next section of flue gas. On the basis of the above steps, it is necessary to open the branch II pipeline switch F and close the branch I pipeline switch E to allow the flue gas to pass through the branch II air intake pipeline D. At the same time, the circulating water pump and the circulating water umbrella-shaped spray gun 4 in the branch II air intake pipeline D are turned on to allow the flue gas to fully react with the absorption liquid and then be discharged through the sintering flue gas outlet pipeline B. Then bring the data of this section of the process into the formula for calculation.

[0069] The purpose of setting the branch I air intake duct C and the branch II air intake duct D in parallel is that when one of the branches is working, the absorption liquid of the other branch can be replaced, and the two branches are used alternately. This can ensure that the chlorine removal and analysis system can work continuously without stopping and will not affect the flue gas emission.

[0070] The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0071] [Example 1]

[0072] Prepare the absorption liquid in advance and add it to the flue gas chlorine removal and analysis device. The mass percentage concentration of NaOH in the absorption liquid is 3%, and the mass percentage concentration of Ca(OH)2 is 1.5%. Use a powerful mixer to mix the acid mud and alkali mud, and then dry the neutralization mud at 100°C until it is completely dry. After the dried material is crushed, a neutralization ash that meets the particle size requirements is obtained. The neutralization ash is batched and premixed with other dust muds to obtain a dust mud mixture, in which the neutralization ash accounts for 7% of the total dust mud mixture. The dust mud mixture is then batched with a variety of iron-containing materials such as rich ore powder and concentrate, and premixed to obtain a premix. In this process, the dust mud mixture accounts for 17% of the total premix ratio. The premix is ​​again batched with fuel and flux, and after a first mixing and a second mixing and granulation, a sintering mixture is obtained. Before spreading, weigh the sintering mixture (recorded as M, unit t), and analyze the mass percentage of chlorine element (recorded as C, unit %), spread the sintering mixture, number the sintering trolley, record the starting position and end position of the trolley corresponding to the spreading process of the weighed sintering mixture, and carry out sintering; the sintering start time of the trolley starting position is the starting time of the sintering flue gas flow measurement, and the sintering end time of the trolley end position is the end time of the sintering flue gas flow measurement. Turn on the flue gas chlorine removal and analysis device, and adjust the liquid flow rate of each spray gun to 600ml / min through the circulating water pump. During the sintering process, measure the flow rate of the sintering flue gas generated by this section of the mixture (recorded as Q, unit m 3 ), and then pass the flue gas into the chlorine removal and analysis device for treatment, and analyze the total chlorine content of the absorption liquid (recorded as W, unit mg / m 3 ). The chlorine content of the treated flue gas was tested, and the removal rate of chlorine in the flue gas was calculated to be 93.18%. The process record results were substituted into the formula to calculate the proportional coefficient ω, which was 0.932. The ω value was less than 0.965, and the proportion of acid mud and alkali mud added to the sintering raw materials needed to be reduced immediately.

[0073] [Example 2]

[0074] Prepare the absorption liquid in advance and add it to the flue gas chlorine removal and analysis device. The mass percentage concentration of NaOH in the absorption liquid is 6.5%, and the mass percentage concentration of Ca(OH)2 is 3%. Use a powerful mixer to mix the acid mud and alkali mud, and then dry the neutralization mud at 110°C until it is completely dry. After the dried material is crushed, a neutralization ash that meets the particle size requirements is obtained. The neutralization ash is batched and premixed with other dust muds to obtain a dust mud mixture, in which the neutralization ash accounts for 1% of the total dust mud mixture. The dust mud mixture is then batched with a variety of iron-containing materials such as rich ore powder and concentrate, and premixed to obtain a premix. In this process, the dust mud mixture accounts for 14% of the total premix ratio. The premix is ​​again batched with fuel and flux, and after a first mixing and a second mixing and granulation, a sintering mixture is obtained. Before spreading, weigh the sintering mixture (recorded as M, unit t), and analyze the mass percentage of chlorine element (recorded as C, unit %), and spread the sintering mixture, number the sintering trolleys, record the starting position and end position of the trolley corresponding to the spreading process of the weighed sintering mixture, and then sinter. Turn on the flue gas chlorine element removal and analysis device, and adjust the liquid flow rate of each spray gun to 1200ml / min through the circulating water pump. During the sintering process, measure the flow rate of sintering flue gas generated by this section of the mixture (recorded as Q, unit m 3 ), and then pass the flue gas into the chlorine removal and analysis device for treatment, and analyze the total chlorine content of the absorption liquid (recorded as W, unit mg / m 3 ). The chlorine content of the treated flue gas was tested, and the removal rate of chlorine in the flue gas was calculated to be 94.25%. The process record results were put into the formula to calculate the proportional coefficient ω as 0.973, and the ω value was greater than 0.965, so there was no need to reduce the proportion of acid mud and alkali mud added to the sintering raw materials.

[0075] [Example 3]

[0076] Prepare the absorption liquid in advance and add it to the flue gas chlorine removal and analysis device. The mass percentage concentration of NaOH in the absorption liquid is 4.5%, and the mass percentage concentration of Ca(OH)2 is 2.3%. Use a powerful mixer to mix the acid mud and alkali mud, and then dry the neutralization mud at 105°C until it is completely dry. After the dried material is crushed, a neutralization ash that meets the particle size requirements is obtained. The neutralization ash is batched and premixed with other dust muds to obtain a dust mud mixture, in which the neutralization ash accounts for 4% of the total dust mud mixture. The dust mud mixture is then batched with a variety of iron-containing materials such as rich ore powder and concentrate, and premixed to obtain a premix. In this process, the dust mud mixture accounts for 15.5% of the total premix ratio. The premix is ​​again batched with fuel and flux, and after a first mixing and a second mixing and granulation, a sintering mixture is obtained. Before spreading, weigh the sintering mixture (recorded as M, unit t), and analyze the mass percentage of chlorine element (recorded as C, unit %), spread the sintering mixture, number the sintering trolleys, record the starting and ending positions of the trolleys corresponding to the spreading process of the weighed sintering mixture, and then sinter. Turn on the flue gas chlorine removal and analysis device, and adjust the liquid flow rate of each spray gun to 900ml / min through the circulating water pump. During the sintering process, measure the flow rate of sintering flue gas generated by this section of the mixture (recorded as Q, unit m 3 ), and then pass the flue gas into the chlorine removal and analysis device for treatment, and analyze the total chlorine content of the absorption liquid (recorded as W, unit mg / m 3 ). The chlorine content of the treated flue gas was tested, and the removal rate of chlorine in the flue gas was calculated to be 93.76%. The process record results were put into the formula to calculate the proportional coefficient ω as 0.976, and the ω value was greater than 0.965, so there was no need to reduce the proportion of acid mud and alkali mud added to the sintering raw materials.

[0077] The present invention realizes the compliant disposal of hazardous wastes by coordinating the sintering process, eliminates the pollution and harm to the environment, and saves a lot of disposal fees and investment costs; the acid sludge and alkali sludge generated by the cold rolling system are processed in a coordinated manner through the sintering process, and the proportion coefficient of the chlorine element in the sintering raw material entering the flue gas is absorbed and analyzed online to calculate the proportion coefficient, and the addition amount of the acid sludge and alkali sludge is dynamically controlled in real time, thereby avoiding the improper addition of acid sludge and alkali sludge affecting the quality of the sintered ore, thereby affecting the smooth operation of the blast furnace and the life of the gas pipeline network; a low-cost and high-efficiency flue gas dechlorination wet process is adopted to solve the secondary pollution caused by the acid sludge and alkali sludge treatment process, improve the chlorine removal rate, and achieve a removal rate far higher than the existing wet process, thereby reducing costs; by The sintering process is used to treat corrosive hazardous wastes, which not only achieves the harmless disposal of acid sludge and alkali sludge and reduces their harm to the environment, but also rationally utilizes the iron resources in the waste and creates considerable economic benefits. An efficient and low-cost flue gas chlorine removal and online analysis method is adopted. The absorption liquid is sprayed into small mist droplets through an umbrella-shaped spray gun in the flue gas pipeline, which fully reacts with the flue gas in the pipeline. At the same time, the umbrella-shaped spray gun also sprays the absorption liquid evenly onto the microporous flue gas filter. The tiny mesh holes are filled with absorption liquid. When the gas passes through the filter, the chlorine element is further fully intercepted. The intercepted chlorine element enters the absorption liquid tank below under the flushing action of the umbrella-shaped spray gun, and finally the analysis and detection of the chlorine element is realized through the potentiometric titration device.

Claims

1. A method for harmless treatment of corrosive hazardous waste, characterized in that: Specifically include: S1. preparing neutralized ash; S2, batching and premixing the neutralized ash with other dust and mud to obtain a dust and mud mixture, wherein the neutralized ash accounts for 1% to 7% of the total dust and mud mixture; S3, premixing the dust-sludge mixture with the iron-containing material to obtain a premix, wherein the dust-sludge mixture accounts for 14% to 17% of the total premix; S4, the premixed material is mixed with the fuel and the flux again, and the mixture is mixed once and granulated twice to obtain a sintering mixture; S5. Distribute, ignite and sinter the sintering mixture. During the sintering process, the sintering flue gas generated by the sintering mixture is passed through a flue gas chlorine removal and analysis device for treatment; S6. Calculate the ratio coefficient of chlorine in the sintering raw materials entering the flue gas. The formula is as follows: In the formula, ω represents the ratio coefficient of chlorine in the sintering raw materials entering the flue gas, Q represents the flow rate of sintering flue gas generated by the mixed material in this section during the sintering process, in cubic meters, and W represents the chloride ion concentration in the sintering flue gas absorption liquid, in mg / m 3 , C represents the mass percentage of chlorine in the sintering mixture, in %, and M represents the mass of the sintering mixture, in tons; S7. Determine the amount of chlorine added to the sintering raw materials according to the value of the ratio coefficient ω of the chlorine element in the sintering raw materials entering the flue gas.

2. A method for harmless treatment of corrosive hazardous waste according to claim 1, characterized in that: In S1, the steps of preparing neutralized ash are as follows: S11, mixing cold rolling acid mud and cold rolling alkali mud in a ratio of 8:1 to 10:1 to make the materials undergo a neutralization reaction, and the mixed materials are neutralized mud; S12, drying the neutralized mud at a temperature of 100-110° C. until the moisture content is less than 1%; S13, drying process, recovering the hydrogen chloride volatilized in the neutralization mud; S14, crushing the dried material; S15: More than 90% of the crushed materials with a particle size less than 1 mm are neutral ash.

3. The method for harmless treatment of corrosive hazardous waste according to claim 1, characterized in that: In S2, the other dust and mud include blast furnace dust, gas mud, sintering machine head dust, converter mud, steelmaking dust, and hot-rolled iron mud; in S3, the iron-containing materials include rich ore powder and concentrate.

4. The method for harmless treatment of corrosive hazardous waste according to claim 1, characterized in that: In S5, the content is as follows: Before laying, the sintering mixture is weighed and the chlorine content is analyzed by mass percentage to obtain the total mass of chlorine brought into the sintering raw materials; The sintering mixture is distributed, the sintering trolleys are numbered, the starting and ending positions of the trolleys corresponding to the distribution process of the weighed sintering mixture are recorded, and ignition and sintering are performed; During the sintering process, the flow rate of the sintering flue gas generated by the sintering mixture of this section is measured, and then the flue gas is passed into the flue gas chlorine removal and analysis device for treatment, and the total chlorine content of the absorption liquid is analyzed to obtain the total mass of chlorine in the sintering flue gas generated by this section of the sintering mixture.

5. The method for harmless treatment of corrosive hazardous waste according to claim 1, characterized in that: In S7, the content is as follows: When the ratio coefficient ω of chlorine in the sintering raw materials entering the flue gas is ≥ 0.965, increase the addition ratio of cold rolling acid mud and cold rolling alkali mud, or continue to maintain the addition amount parameter; When the ratio coefficient ω of chlorine element in the sintering raw materials entering the flue gas is less than 0.965, it is necessary to immediately reduce the addition ratio of cold rolling acid mud and cold rolling alkali mud in the sintering raw materials.

6. A system for harmlessly treating corrosive hazardous wastes according to any one of claims 1 to 5, characterized in that: It includes a flue gas chlorine removal and analysis device, which includes a sintering flue gas inlet pipe A, a sintering flue gas outlet pipe B, a branch I inlet pipe C, and a branch II inlet pipe D. The sintering flue gas inlet pipe A is connected with the branch I inlet pipe C and the branch II inlet pipe D respectively, and the output end of the branch I inlet pipe C and the output end of the branch II inlet pipe D are connected with the sintering flue gas outlet pipe B.

7. A harmless treatment system for corrosive hazardous waste according to claim 6, characterized in that: The internal structures of branch I air inlet pipe C and branch II air inlet pipe D are the same, both including: a branch air inlet pipe, a branch air outlet pipe, and an absorption liquid tank. The branch air inlet pipe is connected to the sintering flue gas inlet pipe A, the branch air outlet pipe is connected to the sintering flue gas outlet pipe B, the branch air inlet pipe is connected to the branch air outlet pipe, and the lower end of the branch air outlet pipe is connected to the absorption liquid tank.

8. A harmless treatment system for corrosive hazardous waste according to claim 7, characterized in that: A flue gas filter is fixedly connected to the connecting point between the branch air inlet pipe and the branch air outlet pipe. The flue gas filter and the transverse section of the branch air inlet pipe are arranged perpendicular to each other. The bottom end of the flue gas filter extends into the absorption liquid in the absorption liquid tank. A submersible pump is arranged in the absorption liquid tank. The submersible pump is connected to a water pipe. A spray gun is arranged at the front end of the water pipe. The submersible pump presses water out of the spray gun through the water pipe. The water pipe is arranged between the branch air inlet pipe and the flue gas filter.

9. A harmless treatment system for corrosive hazardous waste according to claim 8, characterized in that: The spray gun is an umbrella-shaped spray gun, and a potentiometric titrator is arranged inside the absorption liquid tank, and the potentiometric titrator is used to measure the chloride ion concentration in the absorption liquid.

10. A harmless treatment system for corrosive hazardous waste according to claim 8, characterized in that: The absorption liquid is a mixed solution of NaOH and Ca(OH)2, in which the mass percentage concentration of NaOH is 3% to 6.5%, and the mass percentage concentration of Ca(OH)2 is 1.5% to 3%. The liquid flow rate of each spray gun is adjusted to 600 to 1200 ml / min by a submersible pump.

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