A method and device for removing dioxins from metal smelting tail gas by using electrolytic manganese slag

Abstract

The present invention relates to a method and device for removing dioxins from metal smelting tail gas by using electrolytic manganese slag, which belongs to the technical field of metallurgical environmental protection and solves the problems of substandard dioxin emission during electric furnace steelmaking production and low utilization rate of electrolytic manganese slag in the prior art. The method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag is to spray the electrolytic manganese slag into the flue of metal smelting tail gas, and the electrolytic manganese slag catalytically degrades dioxins, wherein the injection amount of the electrolytic manganese slag is 150-200kg / min; wherein the tail gas volume of the metal smelting tail gas is 7000-10000m 3 / h. After degradation, the dioxin toxicity equivalent concentration in the flue gas is less than 0.1ng-TEQ / m 3 , dust concentration <15mg / m 3 , which is lower than the national emission standards.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical environmental protection, and in particular to a method and device for removing dioxins from metal smelting tail gas by utilizing electrolytic manganese slag. Background Art

[0002] Electric furnace steelmaking is a short-process technology in steel production, which has the advantage of low carbon emissions. In recent years, electric furnace steelmaking has shown a rapid development trend. In 2015, the output of electric furnace steel was about 49.03 million tons, accounting for 6.1% of crude steel production. By 2018, the output of electric furnace steel had approached 100 million tons, accounting for 10% of crude steel production. With the continuous improvement of technology, electric furnace steelmaking has made great progress in green clean production, intelligent detection and control on the basis of the original high-efficiency and energy-saving smelting technology. However, electric furnace steelmaking is still developing slowly in dioxin treatment technology and electric furnace waste heat recovery technology, which restricts the improvement of the competitiveness of electric furnace short process. These are problems that must be solved in future electric furnace steelmaking.

[0003] Dioxins are the most toxic substances known in the world and are difficult to be eliminated by natural degradation. Dioxin emissions from the steel industry account for 1 / 3 of the total industrial dioxin emissions, of which the amount of dioxins emitted from the electric furnace steelmaking process is second only to the iron ore sintering process. The steel industry is the main source of industrial dioxin emissions, with annual dioxin emissions reaching 1100TEQ / g. According to the current standard (GB 28664-2012), the toxic equivalent concentration of dioxins in electric furnace smelting must be lower than 0.5ng-TEQ / Nm 3 (Some regions require less than 0.2ng-TEQ / Nm 3 ) can achieve emission standards.

[0004] According to the urgent need for reducing dioxin emissions in the electric furnace steelmaking production process, a treatment method is urgently needed that can effectively reduce dioxin emissions in electric furnace steelmaking production and achieve the goal of green production of electric furnace steelmaking. Summary of the invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a method and device for removing dioxins from metal smelting tail gas using electrolytic manganese slag, which can effectively reduce the emission of dioxins in electric furnace steelmaking production so that the toxic equivalent concentration of dioxins meets the emission standards.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] In one aspect, the present invention provides a method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag, comprising the following steps:

[0008] The electrolytic manganese slag is sprayed into the flue of metal smelting tail gas, and the electrolytic manganese slag catalyzes the degradation of dioxins. The reaction formula is:

[0009] The injection rate of the electrolytic manganese slag is 150-200kg / min;

[0010] The tail gas volume of the metal smelting tail gas is 7000-10000m 3 / h; the toxic equivalent concentration of dioxins is 0.2-0.6ng-TEQ / m 3 .

[0011] Electrolytic manganese slag is waste generated during the production of pure manganese, and is transported to the stockpile and stored in a dammed wet method. The large amount of electrolytic manganese slag not only occupies a large amount of land, but also the harmful substances in the electrolytic manganese slag penetrate into the soil, surface water and groundwater, causing serious environmental pollution and major safety hazards.

[0012] In the present invention, electrolytic manganese slag is used to catalytically degrade dioxins, which can effectively reduce the concentration of dioxins in metal smelting tail gas, reduce the emission of dioxins, and achieve efficient treatment of dioxins in electric furnace smelting tail gas, meet national emission standards, and comply with the concept of green environmental protection. In addition, the present invention uses electrolytic manganese slag to catalytically degrade dioxins in metal smelting tail gas, which can achieve secondary utilization of electrolytic manganese slag and reduce the hazards of electrolytic manganese slag, which has important practical significance.

[0013] Optionally, the electrolytic manganese slag has a particle size of less than 30 μm accounting for more than 85%.

[0014] Optionally, the MnO in the electrolytic manganese slag x The content is 6%-10%.

[0015] In the present invention, electrolytic manganese slag is sprayed into the flue, so that the electrolytic manganese slag contacts the metal smelting tail gas in the flue, and the electrolytic manganese slag catalytically degrades dioxins in the metal smelting tail gas in the flue. The present invention strictly controls the injection amount of the electrolytic manganese slag within the range of 150-200kg / min. When the injection amount of the electrolytic manganese slag is lower than 150kg / min, the electrolytic manganese slag catalytically degrades the dioxins in the metal smelting tail gas incompletely, resulting in the dioxin content failing to meet the national emission standards; when the injection amount of the electrolytic manganese slag is higher than 200kg / min, it causes a waste of resources.

[0016] In addition, in the present invention, the proportion of the electrolytic manganese slag with a particle size of less than 30 μm is greater than 85%, and MnO x The content is 6%-10%. The electrolytic manganese slag with fine particle size increases the contact area with the metal smelting tail gas, and the contact is more complete, which effectively plays the catalytic degradation function of the electrolytic manganese slag on dioxins in the metal smelting tail gas.

[0017] Optionally, the method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag comprises the following steps:

[0018] Step 1: spraying electrolytic manganese slag into a flue of metal smelting tail gas, and performing a first catalytic degradation of the electrolytic manganese slag and the metal smelting tail gas;

[0019] Step 2: sending the electrolytic manganese slag and the metal smelting tail gas into an electrostatic precipitator for a second catalytic degradation, and the electrostatic precipitator discharges the catalytic degradation products.

[0020] Optionally, in step 1, the temperature of the metal smelting tail gas is 600-800°C.

[0021] Optionally, in step 2, the reaction temperature of the electrolytic manganese slag and the metal smelting tail gas is 200-300°C.

[0022] In the present invention, electrolytic manganese slag is used to perform two catalytic degradations on metal smelting tail gas, so that the toxic equivalent concentration of dioxins in the metal smelting tail gas meets the national emission standards. The metal smelting tail gas generated from the electric furnace enters the flue, and the temperature of the metal smelting tail gas in the flue can reach 600-800°C. The electrolytic manganese slag and the metal smelting tail gas are initially contacted in the flue, and the first catalytic degradation is performed, which can remove 10%-30% of dioxins in the metal smelting tail gas.

[0023] After the first catalytic degradation in the flue, the electrolytic manganese slag and the metal smelting tail gas are sent to the electrostatic precipitator for the second catalytic degradation. The temperature in the electrostatic precipitator is in the range of 200-300°C, and the electrolytic manganese slag and the metal smelting tail gas stay in the electrostatic precipitator for a long time, so that the electrolytic manganese slag can achieve efficient catalytic degradation of dioxins in the metal smelting tail gas, and can remove 70%-90% of dioxins in the metal smelting tail gas.

[0024] Optionally, the catalytic degradation product includes dust ash, and the dust ash is returned to the electrolytic manganese slag for recycling.

[0025] Optionally, the MnO in the dust removal ash x When the content is 3%-8%, it is returned to the electrolytic manganese slag bin for continuous recycling;

[0026] The MnO in the dust removal ash x When the content is less than 3%, the dust removal ash is recycled.

[0027] In the present invention, electrolytic manganese slag contacts metal smelting tail gas in the flue and in the electrostatic precipitator respectively, so as to achieve catalytic degradation of dioxins in the metal smelting tail gas by the electrolytic manganese slag, and obtain dust removal ash after catalytic degradation.

[0028] The dust contains a certain amount of MnO x , can be recycled. x When the content of MnO in the dust is above 3%, the dust is returned to the electrolytic manganese slag bin, which increases the circulation times of the dust, improves its utilization efficiency, reduces the consumption of electrolytic manganese slag, and saves the cost of dioxin treatment; when the dust contains MnO x When the content is less than 3%, the valuable elements in the dust ash are recovered and used to make cement retarders, etc., thereby increasing the value of resource utilization of the dust ash and achieving efficient utilization of the electric furnace dust ash.

[0029] Optionally, the toxic equivalent concentration of dioxins in the metal smelting tail gas after catalytic degradation is less than 0.1ng-TEQ / m 3 , dust concentration <15mg / m 3 .

[0030] On the other hand, the present invention also provides a device for completing the method of removing dioxins from metal smelting tail gas using electrolytic manganese slag. The device includes a dust hood, a pneumatic conveying fan, an electrolytic manganese slag bin, a circulating ash bin, an electrostatic precipitator, a dust removal fan and a chimney.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0032] 1. The present invention utilizes electrolytic manganese slag to catalytically degrade dioxins in metal smelting tail gas, and controls the injection amount of electrolytic manganese slag to 150-200kg / min, which can effectively reduce the toxic equivalent concentration of dioxins in metal smelting tail gas. After degradation, the toxic equivalent concentration of dioxins is less than 0.1ng-TEQ / m 3 , in line with national emission standards. At the same time, electrolytic manganese slag is used to catalyze the degradation of dioxins, realizing the reuse of electrolytic manganese slag, effectively reducing the amount of electrolytic manganese slag stacking, and reducing the harm of electrolytic manganese slag to the land.

[0033] 2. The present invention utilizes electrolytic manganese slag to perform two catalytic degradations on dioxins in metal smelting tail gas. The first catalytic degradation of electrolytic manganese slag and metal smelting tail gas is achieved in a flue at a temperature of 600-800°C, and 10%-30% of dioxins in the metal smelting tail gas can be degraded. The second catalytic degradation of electrolytic manganese slag and metal smelting tail gas is achieved in an electrostatic precipitator at a temperature of 200-300°C, and 70%-90% of dioxins in the metal smelting tail gas can be effectively degraded.

[0034] 3. In the present invention, electrolytic manganese slag is fully contacted with dioxin, and catalytic degradation products are obtained after catalytic degradation. The catalytic degradation products include dust, and the dust contains MnO x , when MnOx When the content of MnO is above 3%, the dust removal ash is returned to the electrolytic manganese slag bin for recycling; x When the content is less than 3%, valuable elements such as iron and zinc are recovered to achieve efficient utilization of dust ash and save the cost of dioxin treatment.

[0035] 4. The present invention provides a device for treating dioxins, including a dust collecting hood, a pneumatic conveying fan, an electrolytic manganese slag bin, a circulating ash bin, an electrostatic precipitator, a dust removal fan and a chimney. The device provided by the present invention is highly flexible and can be flexibly constructed according to the configuration of electric furnace steelmaking in different enterprises, without major changes to the original production process, and has the advantages of simple process, economical and practical, and easy to implement.

[0036] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0038] Figure 1 The present invention is a schematic diagram of a device for removing dioxins from metal smelting tail gas by using electrolytic manganese slag.

[0039] In the figure, 1. Electrolytic manganese slag bin; 2. Pneumatic conveying fan; 3. Electrostatic precipitator; 4. Dust removal fan; 5. Chimney; 6. Circulating ash bin. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0041] The present invention provides a method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag, comprising the following steps:

[0042] The electrolytic manganese slag is sprayed into the flue of metal smelting tail gas, and the electrolytic manganese slag catalyzes the degradation of dioxins. The reaction formula is:

[0043] The injection rate of the electrolytic manganese slag is 150-200kg / min;

[0044] The tail gas volume of the metal smelting tail gas is 7000-10000m 3 / h; the toxic equivalent concentration of dioxins is 0.2-0.6ng-TEQ / m 3 .

[0045] Compared with the prior art, the present invention uses electrolytic manganese slag to remove dioxins from metal smelting tail gas. Under the condition that the temperature of electrolytic manganese slag and tail gas is 200-800℃, dioxins are catalytically degraded to generate carbon dioxide, water and hydrogen chloride. The toxic equivalent concentration of dioxins in the metal smelting tail gas after catalytic degradation is less than 0.1ng-TEQ / m 3 , in line with national emission standards. At the same time, it realizes the efficient utilization of electrolytic manganese slag and saves dioxin treatment costs.

[0046] It is worth noting that in order to better achieve the catalytic degradation of dioxins in metal smelting tail gas by electrolytic manganese slag, the present invention controls the injection amount of electrolytic manganese slag to be within the range of 150-200 kg / min, and controls the proportion of particles with a diameter of less than 30 μm in the electrolytic manganese slag to be greater than 85%, and the MnO in the electrolytic manganese slag to be less than 100 μm. x The content of is 6%-10%. Within the above range, the electrolytic manganese slag contacts the dioxins in the metal smelting tail gas more fully, and the catalytic degradation efficiency is higher.

[0047] Exemplarily, the injection amount of electrolytic manganese slag can be 150kg / min, 160kg / min, 170kg / min, 180kg / min, 190kg / min or 200kg / min. At the same time, the injection method of electrolytic manganese slag adopts a powder pneumatic conveying method. The electrolytic manganese slag can be sprayed into the flue from any direction, preferably from the top of the flue, relying on its own gravity to fall freely, with better fluidity and more sufficient contact with metal smelting tail gas. The injection port position of the electrolytic manganese slag is selected at a distance of 8-20m from the electrostatic precipitator according to the different injection amounts. When the distance to the electrostatic precipitator is farther, the injection amount of the electrolytic manganese slag can be relatively less, and the reaction time in the flue is longer; when the distance to the electrostatic precipitator is closer, the injection amount of the electrolytic manganese slag can be relatively increased, the reaction time in the flue is shorter, and the removal amount of dioxins is relatively less. In addition, the flue diameter is 1.5-2m. When the flow rate of electrolytic manganese slag and metal smelting tail gas is constant, the flue diameter will affect the flow rate, and the speed of the flow rate will also affect the removal efficiency, and also affect the temperature of the metal smelting tail gas. At the same time, it is necessary to consider the temperature of the electrolytic manganese slag and metal smelting tail gas entering the electrostatic precipitator. Controlling the temperature of the electrolytic manganese slag and metal smelting tail gas entering the electrostatic precipitator within 200-300℃ is more conducive to promoting the secondary catalytic degradation of dioxins in the metal smelting tail gas in the electrostatic precipitator.

[0048] Specifically, the dust concentration in the flue is 5-10g / m 3.

[0049] A certain amount of dust will be generated during the metal smelting process. In order to catalyze and degrade dioxins in the metal smelting tail gas, electrolytic manganese slag is sprayed into the flue. At this time, the dust concentration in the flue is 5-10g / m 3 within the range.

[0050] It should be noted that in order to reduce the toxic equivalent concentration of dioxins in metal smelting tail gas, the concentration of dust, and save treatment space and cost, the present invention utilizes electrolytic manganese slag to perform two catalytic degradation of dioxins in metal smelting tail gas, including the following steps:

[0051] Step 1: spraying electrolytic manganese slag into a flue of metal smelting tail gas, and performing a first catalytic degradation of the electrolytic manganese slag and the metal smelting tail gas;

[0052] Step 2: sending the electrolytic manganese slag and the metal smelting tail gas into an electrostatic precipitator for a second catalytic degradation, and the electrostatic precipitator discharges the catalytic degradation products.

[0053] Specifically, in step 1, the metal smelting tail gas and electrolytic manganese slag are first catalytically degraded in the flue. At this time, the temperature of the metal smelting tail gas is 600-800°C, and the tail gas volume is 7000-10000m 3 / h. In the flue, electrolytic manganese slag catalytically degrades dioxins in metal smelting tail gas, which can remove 10%-30% of dioxins, and generates carbon dioxide, water and hydrogen chloride after catalytic degradation. After the first catalytic degradation, the uncatalyzed metal smelting tail gas, electrolytic manganese slag and the products after the first catalytic degradation enter the electrostatic precipitator together. The metal smelting tail gas flows in the flue, and the temperature of the metal smelting tail gas in the electrostatic precipitator can be controlled to be 200-300℃ by the injection amount of electrolytic manganese slag, the diameter of the flue, the distance between the injection port of the electrolytic manganese slag and the electrostatic precipitator, etc. At this time, the electrolytic manganese slag fully catalytically degrades the dioxins in the metal smelting tail gas, of which 70%-90% of the dioxins are catalytically degraded to generate carbon dioxide, water and hydrogen chloride, which are discharged after being tested to meet the emission standards.

[0054] In engineering applications, when the diameter of the flue and the distance between the injection port of the electrolytic manganese slag and the electrostatic precipitator are fixed, taking into account the temperature fluctuations of the electrolytic manganese slag and metal smelting tail gas entering the electrostatic precipitator caused by changes in the external environment, a temperature regulating device can be installed on the pipeline between the injection port of the electrolytic manganese slag and the electrostatic precipitator, so that the temperature of the material system reaching the electrostatic precipitator is controlled within 200-300°C, so as to achieve the expected secondary catalytic degradation effect.

[0055] It should be noted that in order to reduce the cost of dioxin treatment and save resources, the dust ash from the catalytic degradation products should be recycled to avoid secondary pollution and waste of resources.

[0056] Specifically, when MnO in dust removal ash x When the content of MnO is 3%-8%, it is returned to the electrolytic manganese slag bin for continuous recycling. x It plays a major role in catalyzing the degradation of dioxins in metal smelting tail gas. In the catalytic degradation process, high-priced MnO x (such as MnO2, Mn2O5) converted into low-priced MnO x (such as MnO, Mn2O3), and in the electrostatic precipitator and subsequent transportation process, most of the low-priced MnO x It is then oxidized to high-valent MnO x , the catalytic activity is restored, so it can continue to be recycled.

[0057] Specifically, in step 3, the MnO in the dust removal ash x When the content is less than 3%, the dust removal ash is recycled.

[0058] The present invention also provides a device for removing dioxins from electrolytic manganese slag. The device comprises a dust collecting hood, an electrolytic manganese slag bin 1, a pneumatic conveying fan 2, an electrostatic precipitator 3, a dust removal fan 4, a chimney 5 and a circulating ash bin 6;

[0059] The dust collecting hood is arranged directly above the electric furnace, and the metal smelting tail gas outlet end above the dust collecting hood is connected with a flue, and along the flow direction of the metal smelting tail gas, the flue is sequentially provided with an electrolytic manganese slag injection port, an electric precipitator 3, a dust removal fan 4 and a chimney 5;

[0060] The outlet end of the electrolytic manganese slag bin 1 is connected to the electrolytic manganese slag injection port through the pneumatic conveying fan 2; the electrostatic precipitator 3 is provided with an inlet, a first outlet and a second outlet, wherein the first outlet is a flue gas outlet, and the second outlet is a dust removal ash outlet, the electrostatic precipitator 3 is connected to the flue through the inlet and the first outlet, and the first outlet is connected to the downstream dust removal fan through the flue;

[0061] A circulating ash bin 6 connected to the second outlet is provided below the electrostatic precipitator 3, and is used to collect dust generated in the electrostatic precipitator 3. A pipeline connected to the electrolytic manganese slag bin 1 is provided below the circulating ash bin 6 to realize the recycling of dust.

[0062] When the electrostatic precipitator is working, the electrolytic manganese slag and dust particles are in a high-voltage electrostatic field, and collide with the positive and negative ions and electrons between the electrodes to become charged. The electrolytic manganese slag and dust particles carrying electrons and ions move toward the opposite electrode under the action of the electric field force and accumulate on the opposite electrode. The dust on the electrode falls into the collection hopper through vibration and other methods. In the electrostatic precipitator, the electrolytic manganese slag comes into contact with the metal smelting tail gas, realizing the secondary catalytic degradation of dioxins by the electrolytic manganese slag, and further removing dioxins.

[0063] In order to explain the present invention clearly, the following examples and comparative examples are provided for illustration.

[0064] Example 1

[0065] This embodiment uses a 35t electric furnace, in which the temperature of steelmaking tail gas is 600°C and the tail gas volume is 7500m 3 / h, the toxic equivalent concentration of dioxins is about 0.5ng-TEQ / m 3 .

[0066] The electrolytic manganese slag is sprayed into the flue of the metal smelting tail gas, and the electrolytic manganese slag catalytically degrades the dioxins in the metal smelting tail gas. The reaction formula is:

[0067] The injection rate of electrolytic manganese slag is 150kg / min, and the proportion of particles with a diameter of less than 30μm in the electrolytic manganese slag is 90%. x The content is about 8%.

[0068] At the same time, the injection method of electrolytic manganese slag adopts the powder pneumatic conveying method; the injection port position of electrolytic manganese slag is selected at a distance of 15m from the electrostatic precipitator according to the injection amount; the diameter of the flue is 1.5m, and the dust concentration in the flue is about 6g / m 3 .

[0069] After testing, the toxic equivalent concentration of dioxins in metal smelting tail gas after catalytic degradation by electrolytic manganese slag is less than 0.1ng-TEQ / m 3 .

[0070] Example 2

[0071] This embodiment uses a 50t electric furnace, in which the temperature of steelmaking tail gas is 700°C and the tail gas volume is 8000m 3 / h, the toxic equivalent concentration of dioxins is about 0.4ng-TEQ / m 3 .

[0072] This embodiment utilizes electrolytic manganese slag to perform two catalytic degradations on metal smelting tail gas, including the following steps:

[0073] Step 1: Spraying electrolytic manganese slag into the flue of metal smelting tail gas, the electrolytic manganese slag and the metal smelting tail gas undergo a first catalytic degradation, the reaction formula is:

[0074] The injection rate of electrolytic manganese slag is 180kg / min, and the proportion of particles with a diameter of less than 30μm in the electrolytic manganese slag is 85%. x The content is about 7%;

[0075] At the same time, the injection method of electrolytic manganese slag adopts the powder pneumatic conveying method. The injection port position of electrolytic manganese slag is selected at a distance of 12m from the electrostatic precipitator according to the injection amount. In addition, the diameter of the flue is 1.6m, and the dust concentration in the flue is about 7g / m 3 .

[0076] Step 2: Send the electrolytic manganese slag and the metal smelting tail gas into the electrostatic precipitator for secondary catalytic degradation. The temperature of the electrolytic manganese slag and the metal smelting tail gas entering the electrostatic precipitator is 300° C. The reaction formula is: The electrostatic precipitator discharges catalytic degradation products.

[0077] After testing, the toxic equivalent concentration of dioxins in metal smelting tail gas after catalytic degradation by electrolytic manganese slag is less than 0.1ng-TEQ / m 3 , dust emission concentration <15mg / m 3 , less than 20mg / m 3 national emission standards.

[0078] Example 3

[0079] The method steps of Example 3 are substantially the same as those of Example 2, except that when the MnO x When the content of MnO is 3%-8%, it is returned to the electrolytic manganese slag bin for continuous recycling; x When the content is less than 3%, the dust removal ash is recycled.

[0080] Example 4

[0081] Reference Figure 1The present invention provides a device for removing dioxins from metal smelting tail gas by using electrolytic manganese slag, comprising an electric furnace, a dust collecting hood arranged just above the electric furnace, the size of the dust collecting hood being adapted to the electric furnace, and the dust collecting hood being used to collect the metal smelting tail gas during the smelting process of the electric furnace; the dust collecting hood is connected to an electrostatic precipitator 3 through a flue, and along the flow direction of the metal smelting tail gas, a pneumatic conveying fan 2 and an electrolytic manganese slag bin 1 are sequentially connected on the flue between the dust collecting hood and the electrostatic precipitator 3; the pneumatic conveying fan 2 blows the electrolytic manganese slag in the electrolytic manganese slag bin 1 Manganese slag is sprayed into the flue between the dust collecting hood and the electrostatic precipitator 3, so that the electrolytic manganese slag comes into contact with the metal smelting tail gas; along the flow direction of the flue gas, the dust removal fan 4 and the chimney 5 are connected in sequence on the electrostatic precipitator 3, and the dust removal fan 4 and the chimney 5 are used to discharge the flue gas generated in the electrostatic precipitator 3; a circulating ash bin is also connected below the electrostatic precipitator 3, and the circulating ash bin is used to collect the dust generated in the electrostatic precipitator 3; a pipeline connected to the electrolytic manganese slag bin 1 is arranged below the circulating ash bin to realize the recycling of dust ash.

[0082] The working process of the device provided by the present invention is as follows: the electric furnace is started to carry out metal smelting, and metal smelting tail gas is generated. The metal smelting tail gas is collected through a dust collecting hood and flows toward the electrostatic precipitator 3 through the flue; the pneumatic conveying fan 2 is started to spray the electrolytic manganese slag in the electrolytic manganese slag bin 1 into the flue filled with metal smelting tail gas, so that the metal smelting tail gas and the electrolytic manganese slag are first contacted in the flue; then, the metal smelting tail gas and the electrolytic manganese slag enter the electrostatic precipitator 3 together, and are fully contacted in the electrostatic precipitator 3 to achieve the catalytic degradation of dioxins in the metal smelting tail gas by the electrolytic manganese slag; after catalytic degradation, dust ash and flue gas are produced, wherein the dust ash is collected in a circulating ash bin, the dust ash can be recycled in the electrolytic manganese slag bin 1, and the dust ash can also be collected for resource utilization; and after the smoke is tested and meets the national emission standards, the smoke is discharged into the chimney 5 along the pipeline through the dust removal fan 4.

[0083] According to the test, the toxic equivalent concentration of dioxins in the metal smelting tail gas after catalytic degradation is less than 0.1ng-TEQ / m 3 , dust emission concentration <12mg / m 3 , less than 20mg / m 3 National emission standards, lower cost.

[0084] Comparative Example 1

[0085] The method steps of Comparative Example 1 are substantially the same as those of Example 1, except that in Comparative Example 1, the electrolytic manganese slag is replaced with manganese-containing tailings. Specifically, the manganese-containing tailings have a particle size of 0.074 to 0.5 mm, accounting for 70% of the total particle size. x The content is 1.5%.

[0086] According to the test, the toxic equivalent concentration of dioxins in the tail gas of metal smelting after catalytic degradation is > 0.2ng-TEQ / m 3 , dust emission concentration>20mg / m 3 .

[0087] Comparative Example 2

[0088] The method steps of Comparative Example 2 are substantially the same as those of Example 1, except that in Comparative Example 2, the electrolytic manganese slag is replaced with manganese-containing tailings. Specifically, the manganese-containing tailings have a particle size of 0.074 to 0.5 mm, accounting for 80% of the total particle size. x The content is 3%.

[0089] According to the test, the toxic equivalent concentration of dioxins in the tail gas of metal smelting after catalytic degradation is > 0.2ng-TEQ / m 3 , dust emission concentration>15mg / m 3 .

[0090] Compared with the prior art, the device provided by the present invention is more flexible, quick and easy to install, can be flexibly constructed according to the electric furnace steelmaking configuration of different enterprises, does not affect the original production process, and has the advantages of being economical, practical and easy to implement.

[0091] In summary, the present invention provides a method and device for removing dioxins from metal smelting tail gas by utilizing electrolytic manganese slag, which fully utilizes the electrolytic manganese slag to catalytically degrade dioxins, adopts a process of spraying electrolytic manganese slag into the metal smelting tail gas and combining it with the metal smelting tail gas, and realizes secondary degradation in the electrostatic precipitator, thereby achieving the purpose of efficient control of dioxins in metal smelting tail gas and efficient and reasonable utilization of electrolytic manganese slag, reducing the burden of dioxin control in metal smelting tail gas of enterprises, having little impact on existing production processes, and having strong innovation and application value.

[0092] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag, characterized in that: The following steps are included: Step 1: spraying electrolytic manganese slag into the flue of metal smelting tail gas, and the electrolytic manganese slag and the metal smelting tail gas undergo a first catalytic degradation; the temperature of the metal smelting tail gas is 600-800° C.; The reaction formula is: , the reaction temperature is 600-800℃; Step 2: sending the electrolytic manganese slag and the metal smelting tail gas into an electrostatic precipitator for a second catalytic degradation, and the electrostatic precipitator discharges the catalytic degradation products; In the step 2, the catalytic degradation temperature of the electrolytic manganese slag and the metal smelting tail gas is 200-300° C.; The injection rate of the electrolytic manganese slag is 150-200kg / min; The tail gas volume of the metal smelting tail gas is 7000-10000m 3 / h; the toxic equivalent concentration of dioxins is 0.2-0.6ng-TEQ / m 3 .

2. The method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag according to claim 1, characterized in that: The electrolytic manganese slag has a particle size of less than 30 μm accounting for more than 85%.

3. The method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag according to claim 1, characterized in that: The electrolytic manganese slag contains MnO x The content is 6%-10%.

4. The method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag according to claim 1, characterized in that: The catalytic degradation product includes dust removal ash, and the dust removal ash is returned to the electrolytic manganese slag for recycling.

5. The method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag according to claim 4, characterized in that: The MnO in the dust removal ash x When the content is 3%-8%, it is returned to the electrolytic manganese slag bin for continuous recycling; The MnO in the dust removal ash x When the content is less than 3%, the dust removal ash is recycled.

6. The method for removing dioxins from metal smelting tail gas by using electrolytic manganese slag according to claim 1, characterized in that: The toxic equivalent concentration of dioxins in metal smelting tail gas after catalytic degradation is less than 0.1ng-TEQ / m 3 , dust concentration <15mg / m 3 .

7. A device for removing dioxins from metal smelting tail gas using electrolytic manganese slag, characterized in that: Used to complete the method of removing dioxins from metal smelting tail gas by using electrolytic manganese slag as described in any one of claims 1 to 6, the device comprises a dust collecting hood, a pneumatic conveying fan, an electrolytic manganese slag bin, a circulating ash bin, an electrostatic precipitator, a dust removal fan and a chimney; The dust collecting hood is arranged directly above the electric furnace, and the metal smelting tail gas outlet end above the dust collecting hood is connected with a flue, and along the flow direction of the metal smelting tail gas, the flue is sequentially provided with an electrolytic manganese slag injection port, an electric precipitator, a dust removal fan and a chimney; The outlet end of the electrolytic manganese slag bin is connected to the electrolytic manganese slag injection port through a pneumatic conveying fan; the electrostatic precipitator is provided with an inlet, a first outlet and a second outlet, wherein the first outlet is a flue gas outlet, and the second outlet is a dust removal ash outlet, the electrostatic precipitator is connected to the flue through the inlet and the first outlet, and the first outlet is connected to the downstream dust removal fan through the flue; A circulating ash bin connected to the second outlet is arranged below the electrostatic precipitator, and is used to collect dust generated in the electrostatic precipitator; a pipeline connected to the electrolytic manganese slag bin is arranged below the circulating ash bin to realize the recycling of dust ash.

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