Experimental method for researching influence of alkali metal on iron-containing furnace charge of blast furnace
By using the alkali metal vapor adsorption method in a vacuum environment to study the effects of alkali metals on blast furnace iron-containing burdens, the problem of the difficulty in separating the individual action mechanism of alkali metals in traditional methods was solved. The migration path of alkali metals and the deterioration law of burdens under vacuum were revealed, providing theoretical support for blast furnace operation and raw material optimization.
Patent Information
- Application Number
- CN202511364843.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2026-01-06
AI Technical Summary
Traditional research methods have shown that alkali metals are difficult to migrate and adsorb in an undisturbed environment during blast furnace smelting, which affects their metallurgical performance. This results in unsystematic mechanistic studies, significant background gas interference, and difficulty in isolating the individual effects of alkali metals.
In a vacuum environment, alkali metal vapor adsorption was used to erode the iron-containing furnace charge in a blast furnace. A mixture of anhydrous potassium carbonate and activated carbon powder was used to generate gaseous elemental potassium and sodium, which were then circulated and enriched into the charge layer through a perforated baffle to eliminate interference from oxygen and reducing gases, thus enabling experimental comparison of different alkali metal concentration gradients.
The study of the independent action mechanism of alkali metals without background gas interference was realized, revealing the phase migration law of sinter and pellets under vacuum, and providing a theoretical basis for blast furnace operation and raw material optimization.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of ironmaking raw material technology, and in particular relates to an experimental method for studying the influence of alkali metals on blast furnace iron-bearing burdens. Background Technology
[0002] During blast furnace smelting, alkali metals (K / Na) accumulate in the furnace charge through a volatilization-condensation cycle, leading to problems such as sinter pulverization, decreased pellet strength, and furnace wall nodule formation. Traditional studies often employ atmospheric pressure or simulated blast furnace atmospheres (CO / CO2 / N2) for alkali metal erosion experiments, but these methods struggle to control alkali metal concentrations and are susceptible to interference from background gases, making it impossible to isolate the individual mechanisms of alkali metal action. Existing technologies lack experimental methods to investigate the impact of alkali metal migration and adsorption on metallurgical properties under undisturbed conditions, resulting in unsystematic mechanistic research. This invention improves experimental methods, contributing to the optimization of processes that enhance the resistance of blast furnace feedstocks to alkali metal erosion. Summary of the Invention
[0003] The purpose of this invention is to provide an experimental method for studying the effects of alkali metals on blast furnace iron-bearing burdens. Addressing the problems of significant background gas interference and difficulty in separating the individual action mechanisms of alkali metals in traditional atmospheric pressure or simulated blast furnace atmosphere experiments, this invention erodes blast furnace iron-bearing burdens under vacuum conditions using alkali metal vapor adsorption, eliminating interference from oxygen and reducing gases. By comparing burdens with different alkali metal concentration gradients with those without alkali metals, the migration paths of alkali metals under vacuum are clarified, realizing the individual action mechanism of alkali metals without background gas interference. This provides a theoretical basis for optimizing the alkali metal resistance of blast furnace raw materials.
[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0005] This invention provides an experimental method for studying the effects of alkali metals on iron-containing blast furnace burdens, comprising the following steps:
[0006] S1. Mix anhydrous potassium carbonate, sodium and activated carbon powder in a certain amount, place it at the bottom of the corundum crucible, then place a perforated partition on top, put iron-containing furnace charge on the upper part of the partition, and cover with a sealing plate.
[0007] In step S1: Anhydrous potassium carbonate, sodium carbonate and activated carbon powder are mixed in a certain amount. The amount of anhydrous potassium carbonate, sodium carbonate and activated carbon powder mixed is determined according to the reaction equations (1-1) and (1-2). Anhydrous sodium carbonate and anhydrous potassium carbonate are used as the alkali metal enrichment source in this step. The experimental amount of activated carbon powder is calculated according to the reaction equation.
[0008] 2C + K₂CO₃ = 2K + 3CO (1.1)
[0009]
[0010] 2C + Na₂CO₃ = 2Na + 3CO (1.2)
[0011]
[0012] In the formula: H1 and H2 are the experimental amounts of anhydrous potassium carbonate and sodium carbonate, respectively, in g; C1 and C2 are the experimental amounts of activated carbon powder that react with potassium carbonate and sodium carbonate to produce potassium and sodium gaseous elements, respectively, in g; x is the experimental amount of iron-containing furnace charge, in g; y is the alkali metal enrichment amount, in %; M1, M2, M3, M4, and M5 are the relative molecular masses of anhydrous potassium carbonate, elemental potassium, activated carbon powder, anhydrous sodium carbonate, and elemental sodium, respectively.
[0013] S2. Place the corundum crucible from S1 into a muffle furnace. After ensuring the vacuum level inside the furnace using a vacuum pump, heat the furnace for 80-100 minutes, hold it at 850-950℃ for 100-1400 minutes to perform gas-phase adsorption, and then cool it to room temperature to obtain alkali-rich iron-containing furnace charge.
[0014] Furthermore, during the process of raising the temperature to 900℃, potassium carbonate and sodium carbonate react with activated carbon powder to generate potassium and sodium gaseous elements. These potassium and sodium gaseous elements pass through the perforated baffle and are then circulated and enriched in the iron-containing furnace charge layer.
[0015] Furthermore, in step S2, the corundum crucible is placed in a muffle furnace, sealed, and then the air inside the furnace is pumped down to below -0.1 MPa to ensure the vacuum level inside the furnace.
[0016] Furthermore, in step S2, the temperature is increased to 850-950℃ at a heating rate of 0.8-1.2℃ / min and held for gas-phase adsorption.
[0017] Furthermore, in step S2, the material is held at this temperature for 120 minutes and then cooled to room temperature to obtain alkali metal-enriched iron-containing furnace charge.
[0018] Furthermore, in step S2, the temperature is increased to 850-950℃ at a heating rate of 1℃ / min and held for gas-phase adsorption.
[0019] Furthermore, the temperature is raised to 900℃ and kept warm.
[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:
[0021] 1. This invention provides an experimental method for studying the effects of alkali metals on blast furnace iron-containing burdens under vacuum conditions. It addresses the challenges of significant background gas interference and difficulty in separating the individual action mechanism of alkali metals in traditional atmospheric pressure or simulated blast furnace atmosphere experiments. By eliminating the interference of oxygen and reducing gases (such as CO / CO2) under an environment of ≤-0.1MPa, the method achieves the first-ever study of the individual action mechanism of soda ash metals.
[0022] 2. Based on the precise measurement of the ratio of anhydrous potassium carbonate / sodium carbonate to activated carbon using chemical reaction equations, the concentration gradient of 0%, 1%, and 2% alkali metals is controlled, overcoming the limitation of traditional solution immersion methods in simulating high-temperature steam concentration. Through customized crucible structure (reaction layer + perforated baffle + furnace charge layer) and temperature control mechanism, the phase migration law of sintered ore and pellets under vacuum is revealed, and the law of alkali metal enrichment on furnace charge deterioration is clarified, providing a theoretical basis for blast furnace operation (such as controlling the temperature of the upper part of the furnace body) and raw material optimization. Detailed Implementation
[0023] An experimental method for studying the effects of alkali metals on iron-bearing blast furnace burdens.
[0024] S1. Mix anhydrous potassium carbonate, sodium carbonate and activated carbon powder, place them at the bottom of the corundum crucible, put a perforated partition on top, put iron-containing furnace charge on top of it, and cover with a sealing plate.
[0025] S2. Then, the corundum crucible described in S1 is placed in a vacuum muffle furnace. After ensuring the vacuum level, the furnace is heated and held at a constant temperature to allow for alkali metal gas phase adsorption. After naturally cooling to room temperature, an alkali metal-rich iron-containing furnace charge is obtained.
[0026] Based on the preparation of samples before the experiment according to step S1, experimental schemes were set up to investigate the effects of different alkali metal enrichment on sinter and pellets. A total of 10 groups of experiments were conducted, namely, no potassium or sodium added - sinter, no potassium or sodium added - pellets, 1% potassium - sinter, 2% potassium - sinter, 1% potassium - pellets, 2% potassium - pellets, 1% sodium - sinter, 2% sodium - sinter, 1% sodium - pellets, and 2% sodium - pellets.
[0027] The required amounts of potassium carbonate, sodium carbonate, and activated carbon powder are shown in Tables 1 and 2. To ensure the full reaction of anhydrous potassium carbonate and sodium carbonate, an excess of activated carbon powder is added. The composition analysis of the iron-containing furnace charge is shown in Table 3.
[0028] Table 1. Amounts of potassium carbonate and activated carbon powder before the experiment (g)
[0029]
[0030] Table 2. Amounts of sodium carbonate and activated carbon powder before the experiment (g)
[0031]
[0032] Table 3. Composition analysis of iron-bearing furnace charge (%)
[0033] sample TFe FeO <![CDATA[SiO2]]> CaO MgO <![CDATA[Al2O3]]> S P F Sintered ore 55.77 9.26 5.25 10.71 2.12 1.94 0.027 0.068 0.11 Pellet Ore 63.78 1.65 4.34 1.32 0.81 1.02 0.003 \ 0.06
[0034] According to step S2, the prepared test sample was placed in a custom-made corundum crucible (anhydrous potassium carbonate, sodium, and carbon powder were mixed at the bottom, a perforated partition was in the middle, and the iron-containing furnace charge was on top). A sealing plate was placed on top, and the crucible was placed in a vacuum muffle furnace. A vacuum pump was used to pressurize the furnace air to below -0.1 MPa to ensure a vacuum level. The temperature was then increased to 900℃ at a rate of 1℃ / min for gas-phase adsorption. After holding at this temperature for 120 min, the crucible was cooled to room temperature, yielding alkali metal-enriched iron-containing furnace charge. Subsequent analysis of the microcrystalline structure and composition can be performed to investigate the influence mechanism of alkali metals on the iron-containing furnace charge. The mass change of the iron-containing furnace charge before and after the experiment is shown in Table 4.
[0035] Table 4. Changes in the mass of iron-containing furnace charge before and after the experiment (g)
[0036]
[0037] In summary, this invention provides an experimental method for studying the effects of alkali metals on blast furnace iron-bearing burdens. Addressing the problems of significant background gas interference and difficulty in separating the individual action mechanisms of alkali metals in traditional atmospheric pressure or simulated blast furnace atmosphere experiments, this invention erodes blast furnace iron-bearing burdens under vacuum conditions using alkali metal vapor adsorption, eliminating interference from oxygen and reducing gases. By comparing burdens with different alkali metal concentration gradients with those without alkali metals, the migration paths of alkali metals under vacuum are clarified, achieving the individual action mechanism of alkali metals without background gas interference. This reveals the phase migration patterns of sintered ore and pellets under vacuum, clarifies the deterioration law of burdens caused by alkali metal enrichment, and provides a theoretical basis for blast furnace operation (such as controlling the temperature of the upper part of the furnace body) and raw material optimization.
[0038] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method of investigating the effect of alkali metals on blast furnace burden comprising the steps of: The method comprises the following steps: S1, mixing anhydrous potassium carbonate, sodium and activated carbon powder according to a certain amount, placing them at the bottom of a corundum crucible, placing a perforated partition on them, placing iron-containing furnace charge on the upper part of the partition, and covering a sealing plate; In step S1, the anhydrous potassium carbonate, sodium and activated carbon powder are mixed according to a certain amount, and the mixing amount of the anhydrous potassium carbonate, sodium and activated carbon powder is determined according to reaction equations (1-1) and (1-2). In this step, anhydrous sodium carbonate and anhydrous potassium carbonate are used as the alkali metal enrichment source, and the experimental amount of activated carbon powder is calculated according to the reaction equation. 2C+K2CO3=2K+3CO(1.1) 2C+Na2CO3=2Na+3CO(1.2) In the formula, H1 and H2 are the experimental amounts of anhydrous potassium carbonate and sodium, respectively, g; C1 and C2 are the experimental amounts of activated carbon powder for generating potassium and sodium gas phase elements by reacting with potassium carbonate and sodium, respectively, g; x is the experimental amount of iron-containing furnace charge, g; y is the alkali metal enrichment amount, %; M1, M2, M3, M4 and M5 are the relative molecular masses of anhydrous potassium carbonate, elemental potassium, activated carbon powder, anhydrous sodium carbonate and elemental sodium, respectively; S2, placing the corundum crucible of S1 into a muffle furnace, using a vacuum pump to ensure the vacuum degree in the furnace, heating for 80-100 min, keeping the temperature at 850-950℃ for 100-1400 min, carrying out gas phase adsorption, and cooling to room temperature to obtain alkali metal-enriched iron-containing furnace charge.
2. The experimental method for investigating the effect of alkali metals on blast furnace burden according to claim 1, characterized in that: During the process of rising to 900℃, potassium carbonate and sodium carbonate will react with activated carbon powder to generate potassium and sodium gas phase elements, which will circulate and enrich in the iron-containing furnace charge layer through the perforated partition.
3. The experimental method for investigating the effect of alkali metals on blast furnace burden according to claim 1, characterized in that: In step S2, the corundum crucible is placed into a muffle furnace, and the air in the furnace is pumped to below -0.1 MPa after sealing to ensure the vacuum degree in the furnace.
4. The experimental method for investigating the effect of alkali metals on blast furnace burden according to claim 1, characterized in that: In step S2, the temperature is raised to 850-950℃ at a heating rate of 0.8-1.2℃ / min, and gas phase adsorption is carried out.
5. The experimental method for investigating the effect of alkali metals on blast furnace burden according to claim 1, characterized in that: In step S2, the temperature is raised to 850-950℃ at a heating rate of 0.8-1.2℃ / min, and gas phase adsorption is carried out.
6. The experimental method for investigating the effect of alkali metals on blast furnace burden according to claim 4, characterized in that: In step S2, the temperature is raised to 850-950℃ at a heating rate of 0.8-1.2℃ / min, and gas phase adsorption is carried out.
7. The experimental method for studying the effect of alkali metals on blast furnace burden according to claim 1, 4 or 6, characterized in that: The temperature is raised to 900℃ and kept.