Method for reducing dioxin by using electrolytic manganese residue and electric field fly ash

Abstract

This invention relates to a method for reducing dioxin emissions using electrolytic manganese slag and electric field dust collector ash, belonging to the technical field of metallurgical environmental protection. The method involves mixing iron ore, fuel, flux, and iron-containing dust slag to obtain a first mixture; the first mixture does not contain electric field dust collector ash; the electrolytic manganese slag is then mixed with the electric field dust collector ash to obtain a second mixture; the first and second mixtures are then combined and sintered, generating dust collector ash and waste gas; the dioxin toxicity equivalent concentration in the waste gas is ≤0.5 ng-TEQ / m³. 3 Discharge is carried out in a timely manner. Under the action of electrolytic manganese slag, not only is the combination of chlorine and hydrocarbons in the electric field dust collector effectively inhibited, but dioxins are also catalytically degraded, reducing the dioxin concentration. This achieves efficient treatment of dioxins in the iron ore sintering process and resource utilization of the electric field dust collector, saving production costs and resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgical environmental protection, and particularly relates to a method for reducing dioxin by using electrolytic manganese residue and electric field dust. BACKGROUND

[0002] With the rapid development of social economy, the demand for steel is increasing sharply, and the steel industry is also developing rapidly, and the steel production is increasing year by year. The steel production is mainly based on the long process of blast furnace-converter, among which the sinter accounts for 70% to 80% of the blast furnace burden structure, and the output is huge.

[0003] The sinter is mainly prepared by sintering raw materials such as iron ore, fuel, flux and iron-containing dust residue. However, with the continuous production of sinter, two problems are brought about. First, environmental pollution: in the sinter production process, harmful substances such as SO2, NO x , dust and dioxin are generated, which are the most important atmospheric pollution emission source and the focus of treatment in steel production. With the gradual implementation and completion of the ultra-low emission transformation project of the steel industry, the sintering of iron ore has realized the comprehensive treatment of SO2, NO x and dust, but the treatment of dioxin in iron ore sintering is still in its infancy, and dioxin is the most toxic substance known at present and is difficult to naturally degrade and eliminate. Second, resource shortage: with the annual production of iron ore sintering, the raw fuel is continuously reduced. Therefore, people think of using electric field dust containing a large amount of iron elements and carbon elements to replace part of the raw fuel to reduce the consumption of raw fuel. However, the electric field dust also contains chlorine elements, and the chlorine elements and the macromolecular carbon (residual carbon) in the raw fuel will form dioxin (PCDD / FS) through the catalysis of some catalytic components (Cu, Fe and other transition metals or their oxides), and the reaction formula is as follows:

[0004]

[0005] As can be seen from the above reaction equation, an important way of dioxin formation in the iron ore sintering process is the combination of chlorine elements and hydrocarbons in the raw fuel. If the contact between the two is reduced and the catalytic degradation of the formed dioxin is promoted, the efficient reduction of dioxin in the iron ore sintering process can be realized. According to the urgent need for reducing dioxin in the iron ore sintering production process and the high chlorine content in the electric field dust, a method is needed to effectively remove dioxin in the iron ore sintering production process and realize the purpose of green production of iron ore sintering. SUMMARY

[0006] In view of the above analysis, the embodiments of the present application aim to provide a method for reducing dioxin by using electrolytic manganese residue and electric field dust, which effectively reduces dioxin in the iron ore sintering production process and realizes resource utilization.

[0007] On one hand, the present invention provides a method for reducing dioxin emissions using electrolytic manganese slag and electric field dust removal ash, characterized by comprising the following steps:

[0008] S1: Iron ore, fuel, flux and iron-containing dust slag are mixed to obtain the first mixture;

[0009] The first mixture does not contain dust from electric field dust removal;

[0010] S2: Electrolytic manganese slag is mixed with electric field dust to obtain a second mixture;

[0011] S3: After mixing the first mixture and the second mixture, sintering is carried out, and dust and exhaust gas are generated after sintering;

[0012] S4: Detect the toxic equivalent concentration of dioxins in the exhaust gas. When the toxic equivalent concentration of dioxins is ≤0.5 ng-TEQ / m³, the concentration is determined. 3 Discharge will be carried out at appropriate times.

[0013] This invention aims to save raw materials and reduce production costs in iron ore sintering by utilizing the dust from electric field dust collectors, which contains large amounts of iron and carbon, as a resource that can replace some of the raw materials. However, the dust from electric field dust collectors contains a large amount of chlorine, which combines with hydrocarbons, increasing the dioxin content.

[0014] In addition, electrolytic manganese slag is one of the wastes generated in the production of pure manganese, and its amount is constantly increasing with the production of manganese. At present, the treatment of electrolytic manganese slag is to transport it to the stockpile and build dams for wet storage. This not only occupies a large amount of land, but also allows a large amount of harmful substances to seep into the soil, surface water and groundwater, posing serious environmental pollution and safety hazards.

[0015] To address the aforementioned problems, this invention mixes field dust collector ash with electrolytic manganese slag to prepare a mixture. On one hand, this reduces the combination of chlorine and hydrocarbons in the field dust collector ash, inhibiting dioxin formation and controlling it at the source. On the other hand, the electrolytic manganese slag contains MnO... x MnO x It can catalytically degrade dioxins at 200-400℃ to produce carbon dioxide, water and hydrogen chloride, and the reaction equation is shown in equation (1).

[0016]

[0017] Furthermore, the proportion of particles with a diameter <30μm in the electrolytic manganese slag is >80%, and the MnO content in the electrolytic manganese slag is <80%. x The content is 5% to 10%.

[0018] Further, the proportion of particle size <38 μm in the electric field dedusting ash is >60%, and the content of Cl element in the electric field dedusting ash is 6%-10%.

[0019] Further, the mass ratio of the electrolytic manganese residue to the electric field dedusting ash is 5-7.

[0020] Further, a method for reducing dioxin by using electrolytic manganese residue and electric field dedusting ash comprises the following steps:

[0021] Step 1, iron ore, fuel, flux and iron-containing dust residue are added into a first cylindrical mixer to prepare a first mixture, and water is added for mixing;

[0022] Step 2, the first mixture is added into a second cylindrical mixer, and water is added for granulation;

[0023] Step 3, the electrolytic manganese residue and the electric field dedusting ash are mixed to prepare a second mixture, and then added into a disc balling machine, and water is added for granulation;

[0024] Step 4, the first mixture and the second mixture are uniformly laid on a sintering trolley for sintering, and sintering flue gas is generated in the sintering process;

[0025] Step 5, the sintering flue gas enters an electric precipitator under the action of a dedusting fan to generate dedusting ash and waste gas;

[0026] Step 6, the waste gas is treated by desulfurization and denitrification, and then discharged through a chimney.

[0027] Further, after the first mixture is granulated, the mass of the material balls with a particle size of 3-5 mm accounts for 30%-50% of the total mass of the material balls.

[0028] Further, after the second mixture is granulated, the mass of the material balls with a particle size of 6-9 mm accounts for 60%-80% of the total mass of the material balls.

[0029] Further, the mass ratio of the second mixture to the first mixture is 0.1-0.3.

[0030] Further, the temperature of the sintering flue gas is 150-300℃, the flue gas volume is 1.0×10 6 -1.5×10 4 m 3 / h, and the dust concentration in the sintering flue gas is 1-5 g / m 3 .

[0031] Further, the toxic equivalent concentration of dioxin in the waste gas is <0.1 ng-TEQ / m 3 , and the emission concentration of dust in the waste gas is <20 mg / m 3 .

[0032] On the other hand, the present invention provides an apparatus for removing dioxins, used to implement the method described in the present invention. The apparatus includes an electrolytic manganese slag bin, an electric field dust removal ash bin, a disc pelletizer, an iron ore bin, a fuel bin, a flux bin, an iron-containing dust slag bin, a first cylindrical mixer, a second cylindrical mixer, a sintering trolley, a flue, a sintering fan, an electrostatic precipitator, a dust removal fan, desulfurization equipment, a desulfurization induced draft fan, denitrification equipment, a denitrification induced draft fan, and a chimney.

[0033] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0034] 1. This invention utilizes the mixing of electrolytic manganese slag and electric field dust collector ash. On one hand, this effectively inhibits the combination of chlorine and hydrocarbons in the electric field dust collector ash, reducing the generation of dioxins; on the other hand, the electrolytic manganese slag contains MnO x MnO x It can catalytically degrade dioxins generated during iron ore sintering, reducing dioxin concentration. With the help of electrolytic manganese slag, it achieves efficient dioxin control during iron ore sintering, while simultaneously realizing the resource utilization of dust from the electric field dust collector, saving production costs and resources.

[0035] 2. In this invention, the proportion of particles with a diameter <30μm in the electrolytic manganese slag is >80%, and the MnO content in the electrolytic manganese slag is <80%. x The content of [unspecified substance] is 5%–10%; the proportion of particles <38μm in the electric field dust collector ash is >60%, and the chlorine (Cl) content in the electric field dust collector ash is 6%–10%; and the mass ratio of electrolytic manganese slag to electric field dust collector ash is 5–7. The combination of electrolytic manganese slag and electric field dust collector ash can effectively inhibit the generation of dioxins and catalytically degrade them, resulting in a dioxin toxicity equivalent concentration <0.1 ng-TEQ / m³. 3 .

[0036] 3. This invention involves mixing iron ore, fuel, flux, and iron-containing dust slag to obtain a first mixture, and mixing electrolytic manganese slag with electric field dust to obtain a second mixture. The first and second mixtures are then granulated and sintered, generating sintering flue gas containing dioxins. During sintering, the electrolytic manganese slag performs a first catalytic degradation of dioxins, removing 80%–90% of them. Uncatalyzed dioxins in the sintering flue gas directly enter an electrostatic precipitator for a second catalytic degradation, removing 10%–20% of the dioxins.

[0037] 4. In this invention, the electrolytic manganese slag undergoes two catalytic degradations of dioxins, generating dust and waste gas in the electrostatic precipitator. To save resources, the dust and electrolytic manganese slag are mixed and recycled, while the waste gas is discharged after denitrification and desulfurization.

[0038] The technical solutions in the present application can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present application will be described in the following description, and some advantages will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. The objects and other advantages of the present application can be achieved and obtained from the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0040] Figure 1 A schematic diagram of the working process for removing dioxins by using electrolytic manganese residue and electric field dust removal ash;

[0041] In the figure, 1 is an electrolytic manganese residue bin; 2 is an electric field dust removal ash bin; 3 is a disc balling machine; 4 is an iron ore bin; 5 is a fuel bin; 6 is a flux bin; 7 is an iron-containing dust residue bin; 8 is a first cylindrical mixer; 9 is a second cylindrical mixer; 10 is a sintering trolley; 11 is a flue; 12 is a sintering fan; 13 is an electric precipitator; 14 is a dust removal fan; 15 is a desulfurization device; 16 is a desulfurization induced draft fan; 17 is a denitration device; 18 is a denitration induced draft fan; and 19 is a chimney. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings form a part of this application and are used to explain the principles of the embodiments of the present application, but are not used to limit the scope of the present application.

[0043] The present application provides a method for reducing dioxins by using electrolytic manganese residue and electric field dust removal ash, in order to remove dioxins generated in the process of iron ore sintering and to realize the resource utilization of electric field dust removal ash, which comprises the following steps:

[0044] S1: mixing iron ore, fuel, flux and iron-containing dust residue to prepare a first mixture;

[0045] The first mixture does not contain electric field dust removal ash;

[0046] S2: mixing electrolytic manganese residue and electric field dust removal ash to prepare a second mixture;

[0047] S3: mixing the first mixture and the second mixture, and then sintering, to generate dust removal ash and waste gas after sintering;

[0048] S4: detecting the toxic equivalent concentration of dioxins in the waste gas, and when the toxic equivalent concentration of dioxins is ≤0.5 ng-TEQ / m 3The exhaust gas is discharged.

[0049] Compared with the prior art, in the present application, iron ore, fuel, flux and iron-containing dust slag are mixed to prepare a first mixture, and the first mixture does not contain electric field dust removal ash; electrolytic manganese slag is mixed with the electric field dust removal ash to prepare a second mixture, and the first mixture and the second mixture are mixed and then sintered.

[0050] In the sintering process, the electrolytic manganese slag effectively inhibits the combination of chlorine elements in the electric field dust removal ash with hydrocarbons in the first mixture, reducing the generation of dioxins; at the same time, the electrolytic manganese slag contains MnO x , which can catalytically degrade dioxins, reducing the emission concentration of dioxins, and the toxic equivalent concentration of dioxins is ≤0.1 ng-TEQ / m 3 , meeting the national emission standards. In addition, the present application realizes the recycling of electrolytic manganese slag and electric field dust removal ash, saving resources and production costs.

[0051] Specifically, the mass ratio of the iron ore, fuel, flux and iron-containing dust slag is: iron ore 70%-80%, fuel 5%-8%, flux 10%-20%, and iron-containing dust slag 5%-10%.

[0052] Specifically, the iron ore is a mixed ore of multiple iron ores.

[0053] Specifically, the fuel is coal powder or coke powder, which provides sufficient heat during the sintering process of the iron ore, ensuring the smooth progress of the sintering process.

[0054] Specifically, the flux is a mixture of dolomite, limestone and quicklime. The flux generates sufficient binding phase during the sintering process of the iron ore, ensuring the strength of the sintered ore.

[0055] Specifically, the iron-containing dust slag is various dust and slag generated during the production process of steel enterprises, such as blast furnace gravity dust removal ash, steel slag tailings or rolling steel iron skin. However, the first mixture does not contain electric field dust removal ash.

[0056] Specifically, the proportion of particle size <30 μm in the electrolytic manganese slag is >80%, and the content of MnO x in the electrolytic manganese slag is 5%-10%.

[0057] Specifically, the proportion of particle size <38 μm in the electric field dust removal ash is >60%, and the content of Cl element in the electric field dust removal ash is 6%-10%.

[0058] Specifically, the mass ratio of the electrolytic manganese slag to the electric field dust removal ash is 5-7.

[0059] It needs to be explained that, in order to remove dioxin generated in iron ore sintering more efficiently, better control the emission concentration of dioxin and dust, the application provides a method for reducing dioxin by using electrolytic manganese residue and electric field dust removal ash, comprising the following steps:

[0060] Step 1, iron ore, fuel, flux and iron-containing dust residue are added into a first cylindrical mixer to prepare a first mixture, and water is added for mixing;

[0061] Step 2, the first mixture is added into a second cylindrical mixer, and water is added for granulation;

[0062] Step 3, the electrolytic manganese residue is mixed with the electric field dust removal ash to prepare a second mixture, which is then added into a disc balling machine, and water is added for granulation;

[0063] Step 4, the first mixture and the second mixture are evenly laid on a sintering trolley for sintering, and sintering flue gas is generated during the sintering process;

[0064] Step 5, the sintering flue gas enters an electric precipitator under the action of a dust removal fan, and dust removal ash and waste gas are generated;

[0065] Step 6, the waste gas is treated by desulfurization and denitrification, and then discharged through a chimney.

[0066] Compared with the prior art, the application first prepares a first mixture and a second mixture, the first mixture is composed of iron ore, fuel, flux and iron-containing dust residue, and does not contain electric field dust removal ash; and the second mixture is composed of electrolytic manganese residue and electric field dust removal ash.

[0067] Then, the first mixture and the second mixture are granulated after adding water, and then placed on a sintering trolley for sintering to generate sintering flue gas containing dioxin. During the sintering process, the electrolytic manganese residue in the second mixture inhibits the combination of chlorine elements in the electric field dust removal ash and hydrocarbons in the first mixture, thereby reducing the generation of dioxin; at the same time, the electrolytic manganese residue contains MnO x The generated dioxin is catalytically degraded, which can remove 80% to 90% of the dioxin in the sintering flue gas.

[0068] The sintering flue gas that is not catalytically degraded enters an electric precipitator to generate dust removal ash and waste gas, and the dust removal ash contains part of the MnO x , which continues to catalytically degrade the dioxin in the sintering flue gas, which can remove 10% to 20% of the dioxin in the sintering flue gas, and finally the waste gas is treated by desulfurization and denitrification before being discharged, and the toxic equivalent concentration of dioxin in the discharged waste gas is <0.1 ng-TEQ / m 3 ; the emission concentration of dust in the waste gas is <20 mg / m 3 .

[0069] Specifically, in the step 1, the mixing time is controlled at 2-4 min, and the first cylinder mixer speed is 4-7 r / min.

[0070] Specifically, in the step 2, the water quantity is 70%-90% of the total water quantity, and the total water quantity is controlled at 7%-9% of the first mixture mass.

[0071] Specifically, in the step 2, the mixing time is controlled at 3-5 min, and the second cylinder mixer speed is 5-8 r / min.

[0072] Specifically, in the step 2, the water quantity is 10%-30% of the total water quantity.

[0073] Specifically, after the first mixture is granulated, the mass of the material balls with a particle size of 3-5 mm accounts for 30%-50% of the total material ball mass.

[0074] Specifically, in the step 3, the balling time is controlled at 7-9 min, the disc balling machine radius is 3-5 m, the speed is 4-7 r / min, and the inclination angle is 43°-50°.

[0075] Specifically, in the step 3, the water quantity is controlled at 6%-8% of the second mixture mass.

[0076] Specifically, after the second mixture is granulated, the mass of the material balls with a particle size of 6-9 mm accounts for 60%-80% of the total material ball mass.

[0077] Specifically, in the step 4, the mass ratio of the second mixture to the first mixture is 0.1-0.3.

[0078] Specifically, in the step 4, the total thickness of the granulated electrolytic manganese residue, the sintering electric field dust removal ash and the sintering mixture is 600-1000 mm.

[0079] More specifically, in the step 4, the sintering mixture is composed of three layers, and the layers from top to bottom are the first mixture ball layer, the second mixture ball layer and the bottom layer.

[0080] The thickness of the first mixture ball layer is 550-900 mm.

[0081] The thickness of the second mixture ball layer is 40-60 mm.

[0082] The bottom layer is composed of finished sintered ore with a particle size of 10-30 mm, and the thickness is 10-40 mm.

[0083] Specifically, in the step 4, the temperature of the sintering flue gas is 150-300 DEG C, the flue gas amount is 1.0*10 6 ~1.5*10 6 m 3 / h, the dust concentration in the sintering flue gas is 1-5 g / m 3 .

[0084]

[0085] Specifically, in the step 5, the temperature of the sintering flue gas is reduced to 100-200 DEG C.

[0086]

[0087] Specifically, the dust collecting ash is returned and mixed with the electrolytic manganese residue to prepare granules.

[0088] The application provides a device for removing dioxin, which is used for realizing the method and effectively inhibits and removes the dioxin generated in iron ore sintering, and realizes the resource utilization of the electrolytic manganese residue and the electric field dust collecting ash.

[0089] Referring to Figure 1 , the device comprises an electrolytic manganese residue bin 1, an electric field dust collecting ash bin 2, a disc balling machine 3, an iron ore bin 4, a fuel bin 5, a flux bin 6, an iron-containing dust residue bin 7, a first cylindrical mixer 8, a second cylindrical mixer 9, a sintering trolley 10, a flue 11, a sintering fan 12, an electric dust collector 13, a dust collecting fan 14, a desulfurization device 15, a desulfurization induced draft fan 16, a denitration device 17, a denitration induced draft fan 18 and a chimney 19.

[0090] When the device works, the electrolytic manganese residue bin 1, the electric field dust collecting ash bin 2, the iron ore bin 4, the fuel bin 5, the flux bin 6 and the iron-containing dust residue bin 7 are independently arranged and used for storing the electrolytic manganese residue, the electric field dust collecting ash, the iron ore, the fuel, the flux and the iron-containing dust residue. The iron ore, the fuel, the flux and the iron-containing dust residue are mixed and then added into the first cylindrical mixer 8 and then added into the second cylindrical mixer 9 to prepare a first mixture, and the first mixture does not contain the electric field dust collecting ash. The electrolytic manganese residue and the electric field dust collecting ash are mixed and then added into the disc balling machine 3 to prepare a second mixture, and the first mixture and the second mixture are laid on the sintering trolley 10 to be sintered.

[0091] Sintering flue gas is generated in the sintering process, and the sintering flue gas is collected in the flue 11, and then the sintering flue gas in the flue 11 flows along the pipeline to the electric dust collector 13 through the sintering fan 12; dust and waste gas are generated in the electric dust collector 13; the waste gas enters the desulfurization equipment 15 for desulfurization treatment through the dust removal fan 14 along the pipeline, and then enters the denitration equipment 17 for denitration treatment through the desulfurization induced draft fan 16, and finally the waste gas after desulfurization and denitration treatment is discharged into the chimney 19 for emission.

[0092] In order to save the treatment cost and realize the recycling use of the dust, the dust is returned to the electric field dust storage bin 2 for storage, and then mixed with the electrolytic manganese residue.

[0093] In the working of the electric dust collector, the electrolytic manganese residue and the dust particles are in a high-voltage electrostatic field, collide with positive and negative ions and electrons between the electrodes to be charged, and the electrolytic manganese residue and the dust particles with electrons and ions are moved to the heterogeneous electrode under the action of the electric field force and accumulated on the heterogeneous electrode, and the dust on the electrode is made to fall into the collection hopper through vibration and other methods. In the electric dust collector, the electrolytic manganese residue and the sintering flue gas are in contact, the electrolytic manganese residue realizes secondary catalytic degradation of dioxin, and further removes dioxin.

[0094] Specifically, a pneumatic conveying fan and another electrolytic manganese residue bin are further connected on the pipeline communicated between the flue 11 and the sintering fan 12, the electrolytic manganese residue in the electrolytic manganese residue bin is sprayed into the pipeline by the pneumatic conveying fan, and the dioxin in the sintering flue gas is catalytically degraded, and the content of dioxin is further reduced.

[0095] In order to clearly explain the present application, the following examples and comparative examples are used for illustration.

[0096] The present application uses 320m 2 The sintering trolley is taken as an example for illustration, and the sources of each raw material are shown in Table 1.

[0097] Table 1 shows the sources of each raw material

[0098]

[0099] Example 1

[0100] The present application provides a method for reducing dioxin by using electrolytic manganese residue and electric field dust, which comprises the following steps:

[0101] Step 1, the iron ore, fuel, flux and iron-containing dust residue are weighed according to the proportion of Table 1, and then added into a first cylindrical mixer to prepare 3.0*10 5 kg of first mixture, and then water is added for mixing;

[0102] The mixing time is 4 minutes, the rotating speed is 6r / min, and the added water accounts for 75% of the total water added, wherein the total water added accounts for 7% of the sintering mixture;

[0103] Step 2, the first mixture is added to a second cylindrical mixer, and water is added for granulation;

[0104] The granulation time is 5 minutes, the rotating speed is 7r / min, and the added water accounts for 25% of the total water added. After granulation, the sintering mixture balls have a particle size of 3-5mm, and the moisture content of the balls is 8%;

[0105] Step 3, the electrolytic manganese residue and the electric field dust removal ash are mixed according to a mass ratio of 1:6 to obtain 6.0×10 4 kg of the second mixture, which is then added to a disc balling machine for granulation;

[0106] The electrolytic manganese residue has a particle size of less than 30μm, and the content of MnO x is about 7%;

[0107] The electric field dust removal ash has a particle size of less than 38μm, and the content of Cl element is about 10%;

[0108] The selected disc balling machine has a radius of 4m, the granulation time is 7 minutes, the rotating speed is 6r / min, and the inclination angle is 45°. After granulation, the mixture balls have a particle size of 6-9mm, and the moisture content of the balls is 7%;

[0109] Step 4, the first mixture and the second mixture are mixed according to a mass ratio of 1:0.2 to obtain a sintering mixture, which is then uniformly laid on a sintering trolley for sintering. During the sintering process, sintering flue gas is generated and enters the main flue under the action of a sintering fan;

[0110] The sintering mixture is composed of three layers, from bottom to top, the first mixture ball layer, the second mixture ball layer, and the bottom layer;

[0111] The thickness of the first mixture ball layer is about 700mm, the thickness of the second mixture ball layer is 50mm, and the thickness of the bottom layer is 20mm;

[0112] The temperature of the flue gas generated during the sintering process is about 200℃, the flue gas volume is about 1.10×10 6 m 3 / h, the dust concentration in the flue gas is about 2g / m 3 , and the toxic equivalent concentration of dioxin in the flue gas is about 0.2ng-TEQ / m 3 .

[0113] At this time, the electrolytic manganese residue catalytically degrades the dioxin in the flue gas, and the reaction equation is represented as:

[0114] Step 5, the sintering flue gas enters the electric precipitator under the action of the dust removal fan to produce dust removal ash and waste gas;

[0115] In the electric precipitator, the temperature of the sintering flue gas is 150℃, and the dust removal ash still contains 2% of MnO x The remaining undegraded dioxin in the sintering flue gas is further catalytically degraded with the dust removal ash; the reaction equation is represented as:

[0116]

[0117] Step 6, the waste gas is treated by desulfurization and denitrification and then discharged through the chimney.

[0118] Finally, the sintering flue gas after removal of dioxin and dust is treated by desulfurization and denitrification and then discharged through the chimney to meet the emission standard; the toxic equivalent concentration of dioxin in the waste gas is <0.1 ng-TEQ / m 3 , lower than the national emission standard of 0.5 ng-TEQ / m 3 ; the emission concentration of dust is <20 mg / m 3 , lower than the national emission standard of 30 mg / m 3 .

[0119] Example 2

[0120] The application provides a method for reducing dioxin by using electrolytic manganese residue and electric field dust removal ash, comprising the following steps:

[0121] Step 1, the iron ore, fuel, flux and iron-containing dust residue are weighed according to the proportion in Table 1, and then added into a first cylindrical mixer to prepare 3.5*10 5 kg of first mixture, and water is added for mixing;

[0122] The mixing time is 3.5 min, the rotating speed is 5 r / min, the amount of added water is 80% of the total amount of added water, and the total amount of added water is controlled to be 7.5% of the amount of sintering mixture;

[0123] Step 2, the first mixture is added into a second cylindrical mixer, and water is added for granulation;

[0124] The granulation time is 4 min, the rotating speed is 6 r / min, and the amount of added water is 20% of the total amount of added water. After granulation, the proportion of the material balls with a particle size of 3-5 mm in the sintering mixture balls reaches 40%, and the water content of the material balls is 7.5%;

[0125] Step 3, the electrolytic manganese residue is mixed with the electric field dust according to the mass ratio of 1:5 to prepare 9.0x10 4 kg of the second mixture, and then added into the disc pelletizer, and water is added for granulation.

[0126] The proportion of the particle size <30 μm in the electrolytic manganese residue is 86%, and the content of MnO x is about 7.5%.

[0127] The proportion of the particle size <38 μm in the electric field dust is about 70%, and the content of Cl element is about 8%.

[0128] The radius of the selected disc pelletizer is 3 m, the granulation time is 8 min, the rotation speed is 5 r / min, and the inclination angle is 47°. After the granulation, the proportion of the material balls with the particle size of 6-9 mm in the granulated mixture is 65%, and the water content of the material balls is 6.5%.

[0129] Step 4, the first mixture and the second mixture are mixed according to the mass ratio of 1:0.25 to prepare a sintering mixture, and then the sintering mixture is uniformly laid on the sintering trolley for sintering. The sintering flue gas is generated in the sintering process and enters the large flue under the action of the sintering fan.

[0130] The sintering mixture is composed of three layers, and from bottom to top, they are the first mixture ball layer, the second mixture ball layer and the laying bottom layer.

[0131] The thickness of the first mixture ball layer is about 750 mm, the thickness of the second mixture ball layer is 40 mm, and the thickness of the laying bottom layer is 25 mm.

[0132] The temperature of the flue gas generated in the sintering process is about 180℃, the flue gas amount is about 1.20x10 6 m 3 / h, the dust concentration in the flue gas is about 3 g / m 3 , and the toxic equivalent concentration of dioxin in the flue gas is about 0.22 ng-TEQ / m 3 .

[0133] At this time, the electrolytic manganese residue catalytically degrades the dioxin in the flue gas, and the reaction equation is represented as:

[0134] Step 5, the sintering flue gas enters the electric precipitator under the action of the dust removal fan to generate dust and waste gas.

[0135] In the electric precipitator, the temperature of the sintering flue gas is 140℃, and the dust removal ash still contains 2.5% of MnO xThe remaining un-degraded dioxins in the sintering flue gas are further catalytically degraded with the dust; the reaction equation is shown as follows:

[0136]

[0137] After the waste gas is further treated by desulfurization and denitrification, it can be discharged through a chimney.

[0138] Finally, after the sintering flue gas after removal of dioxins and dust is further treated by desulfurization and denitrification, it can be discharged through a chimney to meet the standard; the toxic equivalent concentration of dioxins in the waste gas is <0.1 ng-TEQ / m 3 , lower than the national emission standard of 0.5 ng-TEQ / m 3 ; the emission concentration of dust is <15 mg / m 3 , lower than the national emission standard of 30 mg / m 3 .

[0139] Example 3

[0140] The application provides a method for reducing dioxins by using electrolytic manganese residue and electric field dust.

[0141] Step 1, the iron ore, fuel, flux and iron-containing dust residue are weighed according to the proportion in Table 1, and then added into a first cylindrical mixer to prepare 3.2*10 5 kg of first mixture, and water is further added for mixing;

[0142] The mixing time is 3 min, the rotating speed is 7 r / min, the amount of added water is 70% of the total amount of added water, and the total amount of added water is controlled to be 8% of the amount of sintering mixture;

[0143] Step 2, the first mixture is added into a second cylindrical mixer, and water is further added for granulation;

[0144] The granulation time is 3 min, the rotating speed is 8 r / min, and the amount of added water is 30% of the total amount of added water. After the sintering mixture is granulated, the proportion of material balls with a particle size of 3-5 mm reaches 35%, and the water content of the material balls is 8.5%;

[0145] Step 3, the electrolytic manganese residue and the electric field dust are mixed according to a mass ratio of 1:7 to prepare 1.0*10 5 kg of second mixture, which is further added into a disc balling machine, and water is further added for granulation;

[0146] The proportion of electrolytic manganese residue with a particle size of <30 μm is 83%, and the content of MnO x is about 8%;

[0147] The proportion of the particle size < 38 μm in the electric field dust is about 75%, and the content of Cl element is about 9%;

[0148] The radius of the selected disc balling machine is 5 m, the granulation time is 9 min, the rotation speed is 7 r / min, and the inclination angle is 46°. In the granulated mixed balls, the proportion of the balls with a particle size of 6-9 mm is 75%, and the moisture content of the balls is 7.5%;

[0149] Step 4, the first mixed material and the second mixed material are mixed according to a mass ratio of 1:0.3 to obtain a sintering mixed material, and then the sintering mixed material is uniformly laid on a sintering trolley for sintering. Sintering flue gas is generated in the sintering process and enters the large flue under the action of a sintering fan;

[0150] The sintering mixed material is composed of three layers, from bottom to top, the first mixed material ball layer, the second mixed material ball layer and the laying bottom material layer;

[0151] The thickness of the first mixed material ball layer is about 720 mm; the thickness of the second mixed material ball layer is 45 mm, and the thickness of the laying bottom material layer is 30 mm;

[0152] The temperature of the flue gas generated in the sintering process is about 220℃, the flue gas amount is about 1.30×10 6 m 3 / h, the dust concentration in the flue gas is about 2.5 g / m 3 , and the toxic equivalent concentration of dioxin in the flue gas is about 0.21 ng-TEQ / m 3 .

[0153] At this time, the electrolytic manganese slag catalytically degrades the dioxin in the flue gas, and the reaction equation is represented as:

[0154] Step 5, the sintering flue gas enters the electric precipitator under the action of a dust removal fan, and dust removal ash and waste gas are generated;

[0155] In the electric precipitator, the temperature of the sintering flue gas is 170℃, and at the same time, the dust removal ash still contains 3% of MnO x . The remaining undegraded dioxin in the sintering flue gas and the dust removal ash are further catalytically degraded; the reaction equation is represented as:

[0156]

[0157] Step 6, the waste gas can be discharged through a chimney after desulfurization and denitrification treatment.

[0158] Finally, the sintering flue gas after removal of dioxin and dust is treated by desulfurization and denitrification, and then discharged through the chimney to meet the emission standard; the toxic equivalent concentration of dioxin in the exhaust gas is less than 0.1 ng-TEQ / m 3 , lower than the national emission standard of 0.5 ng-TEQ / m 3 ; the dust emission concentration is less than 18 mg / m 3 , lower than the national emission standard of 30 mg / m 3 .

[0159] Comparative Example 1

[0160] Comparative Example 1 and Example 1 are substantially the same in the step of removing dioxin, except that the electrolytic manganese residue in Comparative Example 1 is replaced by manganese-containing tailings. Specifically, the proportion of particle size 0.074-0.5 mm in the manganese-containing tailings is 70%, and the content of MnO x in the manganese-containing tailings is 1.5%.

[0161] It is detected that the toxic equivalent concentration of dioxin in the exhaust gas is greater than 0.2 ng-TEQ / m 3 ; the dust emission concentration is greater than 20 mg / m 3 .

[0162] Comparative Example 2

[0163] Comparative Example 2 and Example 1 are substantially the same in the step of removing dioxin, except that the electrolytic manganese residue in Comparative Example 2 is replaced by manganese-containing tailings. Specifically, the proportion of particle size 0.074-0.5 mm in the manganese-containing tailings is 80%, and the content of MnO x in the manganese-containing tailings is 3%.

[0164] It is detected that the toxic equivalent concentration of dioxin in the exhaust gas is greater than 0.2 ng-TEQ / m 3 ; the dust emission concentration is greater than 15 mg / m 3 .

[0165] Through detection of the toxic equivalent concentration of dioxin and the dust emission concentration in the sintering flue gas after degradation, the removal of dioxin in iron ore sintering by the method provided in Examples 1-3 all meet the national emission standard, and even lower than the national emission standard, in which the toxic equivalent concentration of dioxin is less than 0.1 ng-TEQ / m 3 ; the dust emission concentration is less than 20 mg / m 3 .

[0166] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any change or replacement within the technical range disclosed by the present application can be easily thought by those skilled in the art, which should be covered in the protection scope of the present application.

Claims

1. A method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash, characterized in that, The method comprises the following steps: S1: mixing iron ore, fuel, flux and iron-containing dust slag to obtain a first mixture; The first mixture does not contain electric field dust removal ash; S2: mixing electrolytic manganese slag and electric field dust removal ash to obtain a second mixture; S3: mixing the first mixture and the second mixture, and then sintering to generate dust removal ash and waste gas; S4: detecting the toxic equivalent concentration of dioxins in the exhaust gas, and discharging when the toxic equivalent concentration of dioxins is ≤0.5 ng-TEQ / m 3 .

2. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 1, characterized in that, The proportion of particles with a diameter <30μm in the electrolytic manganese slag is >80%, and the MnO content in the electrolytic manganese slag is <80%. x The content is 5% to 10%.

3. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 1, characterized in that, The electric field dust removal ash has a particle size of less than 38 microns and a Cl content of 6% to 10%.

4. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 1, characterized in that, The mass ratio of the electrolytic manganese slag to the electric field dust removal ash is 1: (5 to 7).

5. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to any one of claims 1-4, characterized in that, The method comprises the following steps: Step 1: adding iron ore, fuel, flux and iron-containing dust slag into a first cylindrical mixer to obtain a first mixture, and adding water to mix; Step 2: adding the first mixture into a second cylindrical mixer to granulate, and adding water to mix; Step 3: mixing electrolytic manganese slag and electric field dust removal ash to obtain a second mixture, and then adding the second mixture into a disc balling machine to granulate, and adding water to mix; Step 4: mixing the granulated first mixture and the granulated second mixture to obtain a sintering mixture, and then uniformly laying the sintering mixture on a sintering trolley to sinter, and generating sintering flue gas during the sintering process; Step 5: the sintering flue gas enters an electric dust collector under the action of a dust removal fan to generate dust removal ash and waste gas; Step 6: the waste gas is treated by desulfurization and denitrification, and then discharged through a chimney.

6. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 5, characterized in that, After the first mixture is granulated, the proportion of balls with a particle size of 3 to 5 mm is 30% to 50%.

7. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 5, characterized in that, After the second mixture is granulated, the proportion of balls with a particle size of 6 to 9 mm is 60% to 80%.

8. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 5, characterized in that, The mass ratio of the granulated first mixture to the granulated second mixture is 1: (0.1 to 0.3).

9. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 5, characterized in that, The temperature of the sintering flue gas is 150-300℃, the sintering flue gas amount is 1.0×10 6 -1.5×10 6 m / h, and the dust concentration in the sintering flue gas is 1-5g / m 3 . 3 ​ 10. The method for reducing dioxin emission by using electrolytic manganese residue and electric field fly ash according to claim 5, characterized in that, The waste gas has a dioxin toxic equivalent concentration < 0.1 ng-TEQ / m 3 The waste gas has a dust emission concentration < 20 mg / m 3 .

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