Preparation method and application of steel slag composite calcium-based solid waste sulfur-fixing agent
By combining steel slag composite calcium-based solid waste sulfur solid agent prepared by solid waste by combining steel slag, calcium carbide slag, shells and red mud, the problems of low resource consumption and sulfur solidification efficiency in the existing technology are solved, and efficient and environmentally friendly coal-fired sulfur solidification effect is achieved.
Patent Information
- Application Number
- CN202510538743.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-05-30
AI Technical Summary
The calcium-based sulfur solid agent used in the existing coal-fired sulfur solidification process depends on natural mineral resources, resulting in excessive resource consumption and difficulty in recycling solid waste. In addition, the solid sulfur solidification efficiency is limited and the cost is high.
By combining steel slag, calcium carbide slag, shells and red mud, a steel slag composite calcium-based solid waste sulfur solid agent is prepared, and calcined at 800°C to 900°C and grinding to obtain the sulfur solid agent.
This method not only reduces solid waste emissions, but also increases the solid sulfur ratio to 70% to 75%, while reducing production costs and promoting the development of the circular economy model of "waste-controlled pollution".
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of coal combustion desulfurization, and particularly relates to a preparation method and application of a steel slag composite calcium-based solid waste desulfurizer. Background Art
[0002] At present, the commonly used calcium-based desulfurizers in the process of coal combustion desulfurization mainly rely on natural mineral resources such as limestone and dolomite. Although such desulfurizers have a certain desulfurization effect, long-term and large-scale use will lead to the overconsumption of natural mineral resources and generate a large amount of solid waste, which is difficult to recycle. In addition, the existing desulfurizers have limited desulfurization efficiency and high costs. Therefore, there is an urgent need to develop a desulfurizer that can save mineral resources and desulfurize efficiently. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a preparation method and application of a steel slag composite calcium-based solid waste desulfurizer in view of the deficiencies of the above-mentioned prior art. The steel slag composite calcium-based solid waste desulfurizer reduces the emission of solid waste through the resource utilization of solid waste and can desulfurize efficiently.
[0004] To solve the above technical problem, the technical solution adopted by the present invention is: A preparation method of a steel slag composite calcium-based solid waste desulfurizer, and the method is as follows: S1. Crush steel slag, carbide slag, shell and red mud respectively to obtain steel slag powder, carbide slag powder, shell powder and red mud powder; S2. After mixing the steel slag powder, carbide slag powder, shell powder and red mud powder obtained in S1, obtain the mixed solid waste; S3. Calcinate the mixed solid waste obtained in S2 at a temperature of 800 °C to 900 °C for 20 min to 30 min, and after natural cooling to room temperature, grind to obtain the steel slag composite calcium-based solid waste desulfurizer.
[0005] Preferably, the particle sizes of the steel slag powder, carbide slag powder, shell powder and red mud powder in S1 are all ≤ 75 μm.
[0006] Preferably, the particle size of the steel slag composite calcium-based solid waste desulfurizer in S3 is ≤ 75 μm.
[0007] Preferably, the percentages of the following calcium-based solid wastes in the total calcium-sulfur ratio in the mixed solid waste in S2 are: steel slag powder 60%, shell powder 15% - 20%, carbide slag powder 15% and red mud powder 5% - 10%.
[0008] The present invention also provides an application of the steel slag composite calcium-based solid waste desulfurizer prepared by the above preparation method. The steel slag composite calcium-based solid waste desulfurizer is used for mixing with coal for coal combustion desulfurization.
[0009] Preferably, the steel slag composite calcium-based solid waste desulfurizer and the coal are mixed according to a total calcium-sulfur ratio of 2.0 to 2.5; The mass m of each calcium-based solid waste in the steel slag composite calcium-based solid waste desulfurizer 废 is calculated as follows: ; In the formula, m 废 is the mass of each calcium-based solid waste, g; k Ca / S is the total calcium-sulfur ratio; φ is the percentage of each calcium-based solid waste in the total calcium-sulfur ratio, %; m 煤 is the mass of the coal, g; w Ca is the mass fraction of calcium in the steel slag composite calcium-based solid waste desulfurizer, %; w S is the mass fraction of sulfur in the coal, %; M Ca is the molar mass of calcium, g / mol; M S is the molar mass of sulfur, g / mol; In the present invention, the mass fraction w of calcium in each solid waste Ca is obtained by XRF (X-ray fluorescence spectrometry) test. The sulfur in the coal is determined according to the method in the national standard GB / T214-2007, and the desulfurization rate of the coal combustion is determined according to the method in GB / T31098-2014; The formula for calculating the total calcium-sulfur ratio k Ca / S is: ; In the formula, k Ca / S is the molar ratio of calcium in the steel slag composite calcium-based solid waste desulfurizer to sulfur in the coal, that is, the total calcium-sulfur ratio; n Ca is the amount of substance of calcium in the steel slag composite calcium-based solid waste desulfurizer, mol; n S is the amount of substance of sulfur in the coal, mol; m 固 is the mass of the steel slag composite calcium-based solid waste desulfurizer, g; m 煤 is the mass of the coal, g; w Ca is the mass fraction of calcium in the steel slag composite calcium-based solid waste desulfurizer, %; w S is the mass fraction of sulfur in the coal, %; M Ca is the molar mass of calcium, g / mol; M S is the molar mass of sulfur, g / mol.
[0010] Preferably, the desulfurization rate of the steel slag composite calcium-based solid waste desulfurizer is 70% to 75%.
[0011] The desulfurization rate is calculated as: ; In the formula, η is the desulfurization rate, %; m S煤 and m S灰are the mass of sulfur in coal and the mass of sulfur in the corresponding ash residue, respectively, in g; Note: m S灰 is the coal and according to the above k Ca / S Calculated to obtain m 固 and m 煤 The ash residue obtained after the combustion process of mixing with
[0012] The present invention has the following advantages compared with the prior art: In the present invention, steel slag, carbide slag, shell and red mud are subjected to solid waste compounding, and through component complementarity (steel slag provides Ca 2 SiO 4 , shell contributes CaCO 3 , carbide slag contributes Ca(OH) 2 , red mud contributes Al 2 O 3 and CaO, optimize the calcium-sulfur ratio and pore structure, break through the performance limitations of single solid waste, achieve a win-win situation in economy and environmental protection, replace traditional desulfurizer raw materials with industrial solid waste, reduce production costs, and promote the "treatment of pollution with waste" circular economy model; the desulfurization rate is increased to 70% - 75%, which can help the clean transformation of the coal-fired industry. The present invention promotes the upgrade of coal-fired pollution control from "end treatment" to "source emission reduction", and has both scientific frontier and engineering practice value.
[0013] The present invention will be further described in detail below with reference to embodiments. Specific embodiments
[0014] Example 1 The preparation method of the steel slag composite calcium-based solid waste desulfurizer in this example is as follows: S1. Crush steel slag, carbide slag, shell and red mud respectively to obtain steel slag powder, carbide slag powder, shell powder and red mud powder; the particle sizes of the steel slag powder, carbide slag powder, shell powder and red mud powder are all ≤ 75 μm; S2. After mixing the steel slag powder, carbide slag powder, shell powder and red mud powder obtained in S1, the mixed solid waste is obtained; The percentages of the following calcium-based solid wastes in the total calcium-sulfur ratio in the mixed solid waste are: steel slag powder 60%, shell powder 20%, carbide slag powder 15%, red mud powder 5%; S3. Calcinate the mixed solid waste obtained in S2 at a temperature of 900 °C for 20 min, cool it naturally to room temperature, and then grind it to obtain the steel slag composite calcium-based solid waste desulfurizer.
[0015] This example also provides the application of the steel slag composite calcium-based solid waste desulfurizer prepared by the above preparation method. The steel slag composite calcium-based solid waste desulfurizer is used to be mixed with coal for coal-fired desulfurization.
[0016] In this embodiment, the steel slag composite calcium-based solid waste desulfurizer and coal are mixed according to a total calcium-sulfur ratio of 2.5; The total calcium-sulfur ratio in this embodiment is 2.5; the mass m of each calcium-based solid waste in the steel slag composite calcium-based solid waste desulfurizer 废 is calculated as follows: ; In the formula, m 废 is the mass of each calcium-based solid waste, g; k Ca / S is the total calcium-sulfur ratio; φ is the percentage of each calcium-based solid waste in the total calcium-sulfur ratio, %; m 煤 is the mass of coal, g; w Ca is the mass fraction of calcium in the steel slag composite calcium-based solid waste desulfurizer, %; w S is the mass fraction of sulfur in coal, %; M Ca is the molar mass of calcium, g / mol; M S is the molar mass of sulfur, g / mol; In this embodiment, the mass fraction w of calcium in each solid waste Ca is obtained by testing with XRF (X-ray fluorescence spectrometry). The sulfur in coal is determined according to the method in national standard GB / T214-2007, and the desulfurization rate of coal combustion is determined according to the method in GB / T31098-2014; The calculation formula for the total calcium-sulfur ratio k Ca / S is: ; In the formula, k Ca / S is the molar ratio of calcium to sulfur in the steel slag composite calcium-based solid waste desulfurizer, that is, the total calcium-sulfur ratio; n Ca is the amount of substance of calcium in the steel slag composite calcium-based solid waste desulfurizer, mol; n S is the amount of substance of sulfur in coal, mol; m 固 is the mass of the steel slag composite calcium-based solid waste desulfurizer, g; m 煤 is the mass of coal, g; w Ca is the mass fraction of calcium in the steel slag composite calcium-based solid waste desulfurizer, %; w S is the mass fraction of sulfur in coal, %; M Ca is the molar mass of calcium, g / mol; M S is the molar mass of sulfur, g / mol.
[0017] The calculation formula for the total calcium-sulfur ratio k Ca / S clarifies the meaning of the calcium-sulfur ratio k Ca / S and points out the relationship between m 固 and m 煤 .
[0018] The sulfur fixation rate of the steel slag composite calcium-based solid waste sulfur fixative in this embodiment is 70% at 900 °C for coal combustion.
[0019] The sulfur fixation rate is calculated as follows: ; In the formula, η is the sulfur fixation rate, %; m S煤 and m S灰 are the mass of sulfur in the coal and the mass of sulfur in the corresponding ash residue, respectively, in g; Note: m S灰 is the ash residue obtained after mixing the coal with m Ca / S calculated according to the above k 固 and m 煤 and burning them in the combustion process.
[0020] Among the raw materials in this embodiment: Steel slag: rich in CaO (40%-50%), SiO 2 (20%-30%) and a small amount of Fe 2 O 3 , its high calcium content and silicate minerals (such as Ca 2 SiO 4 ) can provide sulfur fixation active sites, but the low porosity (<15%) and small specific surface area (<1 m² / g) limit the reaction efficiency.
[0021] The steel slag in this embodiment is sourced from Xugang Iron and Steel Group and contains 42% CaO as determined by XRF; Seashells: mainly composed of CaCO 3 (>95%), which generates porous CaO after high-temperature calcination, and the specific surface area can reach 10-20 m² / g, but its thermal stability is poor and it needs to be compound-modified to improve the anti-sintering ability.
[0022] Red mud: containing Al 2 O 3 (15%-20%), Fe 2 O 3 (10%-15%), which can inhibit the high-temperature decomposition of CaSO 4 .
[0023] The red mud in this embodiment is sourced from Shandong Aluminum Co., Ltd. and has a CaO content of 41%.
[0024] Calcium carbide slag: mainly composed of Ca(OH) 2 (>70%), with high sulfur fixation reaction activity but prone to moisture absorption and caking.
[0025] The calcium carbide slag in this embodiment is sourced from Hunan Yaobo Chemical Trade Company, and its CaO content is 78%; The sulfur fixation mechanism of the steel slag composite calcium-based solid waste sulfur fixative prepared in this embodiment: Steel slag (Ca 2 SiO 4 ), shell (CaCO 3 ), and red mud (Al 2 O 3 ). In the composite desulfurizer, the Ca / S molar ratio is controlled within 2.0 - 2.5 to avoid pore blockage caused by excessive CaO. Calcium carbide slag contains porous Ca(OH) 2 which is beneficial to the adsorption of sulfur oxides. The mesopores (2 - 50 nm) formed after calcining the shell are complementary to the micropores (<2 nm) of the steel slag, constructing a hierarchical porous network and enhancing the diffusion rate of SO 2 .
[0026] When the steel slag is combined with the above other calcium-containing solid wastes, the active sites where the inert components in the steel slag may undergo sulfation reaction are promoted. Under high-temperature conditions, the crystal components in the composite solid waste can disperse with each other to form solid solutions and generate a microstructure conducive to gas-solid reactions. Due to the interaction among the components of several solid wastes after mixing, the desulfurization of the composite solid waste produces a synergistic effect.
[0027] The main components in the shell, calcium carbide slag, and red mud are CaCO 3 , Ca(OH) 2 , and CaO, which are mainly calcium-containing desulfurizers. The steel slag mainly contains Ca 2 SiO 4 , Ca 3 SiO 5 and other calcium-containing silicates. These components cooperate to form a complementary effect in the sulfation reaction. The surface diffusion, product layer diffusion, and changes in the surface morphology of the reactant particles during the desulfurization gas-solid reaction process are all related to the interaction of these components.
[0028] In addition, the multi-component combination of the steel slag composite solid waste desulfurizer enables the inert components to generate a Zener pinning force at the active sites of the active reactants, creating a steric hindrance to the sintering of the reactant particles, promoting the formation of a fluffy structure of the reaction particles, weakening the sintering of the particles, and thus facilitating the progress of the sulfation reaction.
[0029] Example 2 The preparation method of the steel slag composite calcium-based solid waste desulfurizer in this example is as follows: S1. Crush the steel slag, calcium carbide slag, shell, and red mud respectively to obtain steel slag powder, calcium carbide slag powder, shell powder, and red mud powder; the particle sizes of the steel slag powder, calcium carbide slag powder, shell powder, and red mud powder are all ≤75 μm; S2. After mixing the steel slag powder, calcium carbide slag powder, shell powder, and red mud powder obtained in S1, obtain the mixed solid waste; The percentages of the following calcium-based solid wastes in the total calcium-sulfur ratio in the mixed solid waste are as follows: steel slag powder 60%, shell powder 15%, carbide slag powder 15%, red mud powder 10%. S3. Calcinate the mixed solid waste obtained in S2 at a temperature of 800 °C for 30 min, naturally cool it to room temperature, and then grind it to obtain a steel slag composite calcium-based solid waste desulfurizer.
[0030] This embodiment also provides an application of the steel slag composite calcium-based solid waste desulfurizer prepared by the above preparation method. The steel slag composite calcium-based solid waste desulfurizer is used for mixing with coal for coal combustion desulfurization.
[0031] In this embodiment, the steel slag composite calcium-based solid waste desulfurizer and coal are mixed according to a total calcium-sulfur ratio of 2.0; the calculation method is the same as that in Embodiment 1. The desulfurization rate of the steel slag composite calcium-based solid waste desulfurizer in this embodiment during coal combustion at 1000 °C is 75%.
[0032] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent variations made to the above embodiments based on the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.
Claims
1. A method for preparing a steel slag composite calcium-based solid waste desulfurizing agent, characterized in that: The method is: S1, crushing steel slag, carbide slag, shells and red mud respectively to obtain steel slag powder, carbide slag powder, shell powder and red mud powder respectively; S2, mixing the steel slag powder, carbide slag powder, shell powder and red mud powder obtained in S1 to obtain mixed solid waste; S3. The mixed solid waste obtained in S2 is calcined at a temperature of 800° C. to 900° C. for 20 min to 30 min, naturally cooled to room temperature, and then ground to obtain a steel slag composite calcium-based solid waste desulfurization agent.
2. The method for preparing a steel slag composite calcium-based solid waste desulfurizing agent according to claim 1, characterized in that: The particle sizes of the steel slag powder, carbide slag powder, shell powder and red mud powder in S1 are all ≤75 μm.
3. The method for preparing a steel slag composite calcium-based solid waste desulfurizing agent according to claim 1, characterized in that: The particle size of the steel slag composite calcium-based solid waste desulfurization agent described in S3 is ≤75μm.
4. The method for preparing a steel slag composite calcium-based solid waste desulfurizing agent according to claim 1, characterized in that: The percentage of the following calcium-based solid wastes in the mixed solid waste described in S2 in the total calcium-sulfur ratio is: steel slag powder 60%, shell powder 15%-20%, carbide slag powder 15% and red mud powder 5%-10%.
5. An application of a steel slag composite calcium-based solid waste desulfurizing agent prepared by the preparation method according to any one of claims 1 to 4, characterized in that: The steel slag composite calcium-based solid waste desulfurizing agent is used to be mixed with coal to carry out coal combustion desulfurization.
6. The use according to claim 5, characterized in that: The steel slag composite calcium-based solid waste desulfurizing agent is mixed with the coal at a total calcium-sulfur ratio of 2.0 to 2.5; The mass m of each calcium-based solid waste in the steel slag composite calcium-based solid waste desulfurization agent 废 The calculation is as follows: ； In the formula, m 废 is the mass of each calcium-based solid waste, g; k Ca / S is the total calcium-sulfur ratio; φ is the percentage of each calcium-based solid waste in the total calcium-sulfur ratio, %; m 煤 is the mass of coal, g; w Ca is the mass fraction of calcium in the steel slag composite calcium-based solid waste desulfurizer, %; w S is the mass fraction of sulfur in coal, %; M Ca is the molar mass of calcium, g / mol; M S is the molar mass of sulfur, g / mol.
7. The use according to claim 6, characterized in that: The steel slag composite calcium-based solid waste desulfurization agent has a desulfurization rate of 70% to 75%.