Blast furnace flue gas dechlorinating agent prepared from red mud as well as preparation method and application of blast furnace flue gas dechlorinating agent

Abstract

The invention discloses a blast furnace flue gas dechlorinating agent prepared from red mud and a preparation method and application of the blast furnace flue gas dechlorinating agent, and belongs to the technical field of energy conservation and environmental protection. In the process, firstly, the red mud is calcined and ground into powder; and then adding silica sol and polyethylene glycol into the red mud powder, carrying out extrusion molding, and roasting to prepare the dechlorinating agent with certain strength. Compared with the conventional calcium oxide dechlorinating agent, the dechlorinating agent taking the red mud as the active component has the advantages of no pulverization, simple preparation process and low cost, and the red mud belongs to solid waste, so that the purpose of treating waste with waste can be realized when the dechlorinating agent is prepared from the red mud. The dechlorinating agent prepared by the method is used for removing hydrogen chloride in blast furnace gas, and has the characteristics of high removal rate, long penetration time and high chlorine capacity.

Description

Technical Field

[0001] This invention belongs to the field of solid waste recycling technology, specifically relating to a method for preparing a blast furnace flue gas dechlorination agent using red mud and its application. Background Technology

[0002] The blast furnace top gas contains HCl, which can easily cause corrosion of TRT blades and pipes. Therefore, it is necessary to remove HCl from the gas components before it enters the gas pipeline. Red mud is a highly alkaline solid waste generated during the alumina refining process from bauxite. It is named for its red color due to its high iron oxide content. One to two tons of red mud are generated for every ton of alumina produced, making it a representative of large-volume solid waste. Red mud is characterized by its complex composition, strong alkalinity, and fine particles, and can be used as a dechlorinating agent for blast furnace flue gas, achieving "waste treatment with waste."

[0003] Red mud contains various metal oxides, and its potential catalytic activity makes it a high-quality raw material for the low-cost preparation of porous catalysts with high specific surface area. Patent application CN120205235A discloses a method for preparing a catalyst using red mud as raw material through hydrothermal reaction and secondary calcination. This patent mixes calcined red mud with titanium dioxide acid hydrolysis waste residue and desulfurization waste liquid, and prepares the catalyst through stirring, hydrothermal reaction, and calcination. The catalyst achieves efficient removal of COD, ammonia nitrogen, total phosphorus, and heavy metal pollutants from the waste liquid through photocatalysis. Patent CN120157149A discloses a method for preparing SOD molecular sieves using red mud and fly ash. This patent mixes red mud and fly ash in a certain proportion, performs acid leaching treatment, and uses alkali melting and high-pressure hydrothermal methods to treat the acid leaching product, preparing SOD molecular sieves with high silicon-to-aluminum ratio and high crystallinity. Patent CN120097434A uses red mud as raw material, introduces dolomite to regulate the alkalinity of the system to activate the adsorption activity of the red mud, utilizes the high specific surface area of ​​diatomaceous earth to enhance mass transfer and dispersibility, and supplements it with sodium polyacrylate to achieve rapid flocculation and separation of adsorbed pollutants. This forms a synergistic removal mechanism for COD, ammonia nitrogen, and total phosphorus, significantly improving treatment efficiency. Summary of the Invention

[0004] To address the problems of current blast furnace gas dechlorination agents being prone to pulverization and having high costs, this invention provides a method for preparing a blast furnace flue gas dechlorination agent using red mud, along with its application.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A dechlorinating agent for blast furnace flue gas prepared using red mud, wherein the dechlorinating agent is composed of an active component prepared from red mud, a binder, and a pore-forming agent; wherein the active component accounts for 50-80 wt% of the total mass fraction, the binder accounts for 15-30 wt% of the total mass fraction, and the pore-forming agent accounts for 5-20 wt% of the total mass fraction.

[0007] Furthermore, the active components are calcium oxide, calcium carbonate, and other alkaline substances from red mud.

[0008] Table 1 shows the composition of red mud. It can be seen that the content of CaCO3 in red mud exceeds 40%. If this part of CaCO3 is converted into CaO, the dechlorination effect can be improved.

[0009] Table 1 Composition of Red Mud

[0010]

[0011] Furthermore, the pore-forming agent is polyethylene glycol; the binder is silica sol, or an inorganic binder based on bentonite.

[0012] A method for preparing a blast furnace flue gas dechlorination agent using red mud includes the following steps:

[0013] Step 1: Grind the dried red mud into red mud powder with a particle size of <100 mesh, and then calcine it at high temperature and cool it.

[0014] Step 2: Then, the red mud powder treated in Step 1 is mixed with binder and pore-forming agent to obtain mud slurry;

[0015] Step 3: Extrusion molding to form columnar clay strips;

[0016] Step 4: Then, the columnar clay strips are roasted a second time to obtain the dechlorination agent.

[0017] Furthermore, the pore-forming agent is polyethylene glycol; the binder is silica sol, or an inorganic binder based on bentonite.

[0018] Furthermore, the mass ratio of the red mud, pore-forming agent, and binder is 50~80:5~20:15~30.

[0019] Furthermore, in step 1, the calcination temperature is greater than 850°C, and the calcination time is 3-6 hours. Preferably, calcination is carried out at 850-1300°C for 5 hours.

[0020] Furthermore, in step 4, the temperature of the second roasting is 300℃, and the roasting time is 3~5h.

[0021] An application of a blast furnace flue gas dechlorinating agent prepared by the method described above for removing hydrogen chloride from blast furnace flue gas.

[0022] Furthermore, the dechlorination reaction conditions are: reaction temperature between room temperature and 120°C; space velocity between 500 and 2000 h⁻¹. -1 The concentration of hydrogen chloride in the purified gas is reduced to below 1 ppm, and the saturated chlorine capacity is greater than 14%.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) It realizes the resource utilization of industrial solid waste, with a simple preparation process and low cost;

[0025] (2) It has a well-developed pore structure, a large specific surface area, strong adsorption capacity, and significant chlorine capacity and dechlorination effect;

[0026] (3) The catalyst after dechlorination has high compressive strength, overcoming the disadvantage of high pulverization of traditional dechlorination agents;

[0027] (4) It has a wide applicable temperature window and can be used in the range of room temperature to 120℃;

[0028] (5) The dechlorinating agent after dechlorination can recover the metal elements in it, realize the resource recycling of pollutants, and improve the economic efficiency of the process. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the dechlorination agent preparation process;

[0031] Figure 2 This is a picture of the actual dechlorination agent. Detailed Implementation

[0032] To gain a deeper understanding of this invention, we will provide a comprehensive and detailed description. However, this invention has various implementations and is not limited to the specific examples listed herein. These examples are presented to enhance a full understanding of the disclosure of this invention.

[0033] Example 1

[0034] The dechlorination agent is prepared according to the method described in this invention: (1) the crushed red mud is ground into red mud powder with a particle size of less than 100 mesh; (2) the ground red mud powder is calcined in a muffle furnace at 900°C for 5 hours; (3) a binder mainly composed of silica sol is added, the amount of which is 10 wt% of the total dechlorination agent, and 5 wt% of a pore-forming agent mainly composed of polyethylene glycol is added, and the mixture is extruded into a column with a diameter of 4 mm; (4) the mixture is calcined in a muffle furnace at 300~350°C for 3 hours to form the dechlorination agent product.

[0035] The prepared dechlorination agent was loaded into a fixed-bed reactor to remove hydrogen chloride from the coal gas. The simulated coal gas composition was: CO concentration 30 vol%, H2 concentration 30 vol%, CO2 concentration 15 vol%, O2 concentration 0.01 vol%, and water vapor concentration 5 vol%. The flow rate of this mixed gas was set to 100 mL / min. Diluted hydrochloric acid was injected into the fixed bed through a metering pump at a flow rate of 0.1 mL / min. The hydrogen chloride content in the coal gas was 4.32 g / Nm³. 3 The dechlorination reaction conditions are: volume hourly space velocity (VHSV) 1500 h⁻¹. -1 The reaction pressure was atmospheric pressure, the dechlorination reaction temperature was 100℃, and the hydrogen chloride content in the dechlorinated gas was <1 mg / Nm³. 3 The desulfurization efficiency is >99%, and the saturated chlorine capacity of the dechlorinating agent is 16.1%.

[0036] Example 2

[0037] The dechlorination agent is prepared according to the method described in this invention: (1) the crushed red mud is ground into red mud powder with a particle size of less than 100 mesh; (2) the ground red mud powder is calcined in a muffle furnace at 900°C for 5 hours; (3) a binder mainly composed of silica sol is added, the amount of which is 15 wt% of the mass of the red mud powder, and a pore-forming agent mainly composed of polyethylene glycol is added, which is equivalent to 10 wt% of the red mud powder. The mixture is then extruded into a column with a diameter of 4 mm; (4) the mixture is calcined in a muffle furnace at 300~350°C for 3 hours to form the dechlorination agent.

[0038] The prepared dechlorination agent was loaded into a fixed-bed reactor to remove hydrogen chloride from the coal gas. The simulated coal gas composition was: CO concentration 30 vol%, H2 concentration 30 vol%, CO2 concentration 15 vol%, O2 concentration 0.01 vol%, and water vapor concentration 5 vol%. The flow rate of this mixed gas was set to 100 mL / min. Diluted hydrochloric acid was injected into the fixed bed through a metering pump at a flow rate of 0.1 mL / min. The hydrogen chloride content in the coal gas was 4.32 g / Nm³. 3 The dechlorination reaction conditions are: volume hourly space velocity (VHSV) 1500 h⁻¹. -1 The reaction pressure was atmospheric pressure, the dechlorination reaction temperature was 100℃, and the hydrogen chloride content in the dechlorinated gas was <1 mg / Nm³. 3 The desulfurization efficiency is >99%, and the saturated chlorine capacity of the dechlorinating agent is 14.5%.

[0039] Example 3

[0040] The dechlorination agent is prepared according to the method described in this invention: (1) the crushed red mud is ground into red mud powder with a particle size of less than 100 mesh; (2) the ground red mud powder is calcined in a muffle furnace at 900°C for 5 hours; (3) a binder mainly composed of silica sol is added, the amount of which is 20 wt% of the mass of the red mud powder, and a pore-forming agent mainly composed of polyethylene glycol is added, which is equivalent to 5 wt% of the mass of the red mud powder. The mixture is then extruded into a column with a diameter of 4 mm; (4) the mixture is calcined in a muffle furnace at 300~350°C for 3 hours to form the dechlorination agent.

[0041] The prepared dechlorination agent was loaded into a fixed-bed reactor to remove hydrogen chloride from the coal gas. The simulated coal gas composition was: CO concentration 30 vol%, H2 concentration 30 vol%, CO2 concentration 15 vol%, O2 concentration 0.01 vol%, and water vapor concentration 5 vol%. The flow rate of this mixed gas was set to 100 mL / min. Diluted hydrochloric acid was injected into the fixed bed through a metering pump at a flow rate of 0.1 mL / min. The hydrogen chloride content in the coal gas was 4.32 g / Nm³. 3 The dechlorination reaction conditions are: volume hourly space velocity (VHSV) 1500 h⁻¹. -1 The reaction pressure was atmospheric pressure, the dechlorination reaction temperature was 100℃, and the hydrogen chloride content in the dechlorinated gas was <1 mg / Nm³. 3 The desulfurization efficiency is >99%, and the saturated chlorine capacity of the dechlorinating agent is 13.8%.

[0042] Example 4

[0043] The dechlorination agent is prepared according to the method described in this invention: (1) the crushed red mud is ground into red mud powder with a particle size of less than 100 mesh; (2) the ground red mud powder is calcined in a muffle furnace at 900°C for 5 hours; (3) a binder mainly composed of silica sol is added, the amount of which is 15 wt% of the mass of the red mud powder, and a pore-forming agent mainly composed of polyethylene glycol is added, which is equivalent to 10 wt% of the red mud powder. The mixture is then extruded into a column with a diameter of 4 mm; (4) the mixture is calcined in a muffle furnace at 300~350°C for 3 hours to form the dechlorination agent.

[0044] The prepared dechlorination agent was loaded into a fixed-bed reactor to remove hydrogen chloride from the coal gas. The simulated coal gas composition was: CO concentration 30 vol%, H2 concentration 30 vol%, CO2 concentration 15 vol%, O2 concentration 0.01 vol%, and water vapor concentration 5 vol%. The flow rate of this mixed gas was set to 100 mL / min. Diluted hydrochloric acid was injected into the fixed bed through a metering pump at a flow rate of 0.1 mL / min. The hydrogen chloride content in the coal gas was 4.32 g / Nm³. 3 The dechlorination reaction conditions are: volume hourly space velocity (VHSV) 1500 h⁻¹. -1 The reaction pressure was atmospheric pressure, the dechlorination reaction temperature was 100℃, and the hydrogen chloride content in the dechlorinated gas was <1 mg / Nm³. 3The desulfurization efficiency is >99%, and the saturated chlorine capacity of the dechlorinating agent is 15.8%.

[0045] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for preparing blast furnace flue gas dechlorination agent using red mud, characterized in that: The dechlorination agent is composed of active components prepared from red mud, a binder, and a pore-forming agent; the active components account for 50-80 wt% of the total mass, the binder accounts for 15-30 wt% of the total mass, and the pore-forming agent accounts for 5-20 wt% of the total mass.

2. The method for preparing blast furnace flue gas dechlorination agent using red mud according to claim 1, characterized in that: The active components are CaCO3, SiO2, Al2O3, Fe2O3, TiO2, Na2O, MgO, and K2O from red mud.

3. The method for preparing blast furnace flue gas dechlorination agent using red mud according to claim 1, characterized in that: The pore-forming agent is polyethylene glycol; the binder is silica sol, or an inorganic binder based on bentonite.

4. A method for preparing a blast furnace flue gas dechlorination agent using red mud, characterized in that: Includes the following steps: Step 1: Grind the dried red mud into red mud powder with a particle size of <100 mesh, and then calcine it at high temperature and cool it. Step 2: Then, the red mud powder calcined in Step 1 is mixed with the binder and pore-forming agent to obtain mud slurry; Step 3: Extrusion molding to form columnar clay strips; Step 4: Then, the columnar clay strips are roasted a second time to obtain the dechlorination agent.

5. The method for preparing a blast furnace flue gas dechlorination agent using red mud according to claim 4, characterized in that: The pore-forming agent is polyethylene glycol; the binder is silica sol, or an inorganic binder based on bentonite.

6. The method for preparing a blast furnace flue gas dechlorination agent using red mud according to claim 4, characterized in that: The mass ratio of the red mud, pore-forming agent, and binder is 50~80:5~20:15~30.

7. The method for preparing a blast furnace flue gas dechlorination agent using red mud according to claim 4, characterized in that: In step 1, the roasting temperature is greater than 850°C, and the roasting time is 3-6 hours.

8. The method for preparing a blast furnace flue gas dechlorination agent using red mud according to claim 4, characterized in that: In step 4, the second roasting temperature is 300℃ and the roasting time is 3~5h.

9. The application of a blast furnace flue gas dechlorinating agent prepared by the preparation method according to any one of claims 4 to 8 for the removal of hydrogen chloride from blast furnace flue gas.

10. The application of the blast furnace flue gas dechlorinating agent according to claim 9 in removing hydrogen chloride from blast furnace flue gas, characterized in that: The dechlorination reaction conditions are: reaction temperature between room temperature and 120℃; space velocity between 500 and 2000 h⁻¹. -1 The concentration of hydrogen chloride in the purified gas is reduced to below 1 ppm, and the saturated chlorine capacity is greater than 14%.

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