Application of an electrofused magnesium lanthanum / cerium-based refractories in rare earth steel ladles
The problem of rare earth loss in rare earth steel smelting was solved by electrofused magnesium lanthanum/cerium-based refractory materials, which improved the rare earth yield and the refractory performance of the ladle, and achieved the stability of the rare earth steel smelting process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHEASTERN UNIV CHINA
- Filing Date
- 2024-04-30
- Publication Date
- 2026-06-30
Smart Images
Figure CN118515493B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of refractory materials technology, specifically relating to the application of an electrofused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles. Background Technology
[0002] The stability of rare earth steel smelting processes and its properties has long been a key challenge hindering its production and application. This manifests in low rare earth yield, difficulty in controlling inclusions, and severe nozzle blockage, leading to inconsistent rare earth steel performance. The root cause lies in the fact that current rare earth steel smelting processes still utilize traditional refractory materials in their ladles and tundishes.
[0003] Traditional refractory materials are primarily magnesia-based, often incorporating Al₂O₃ to enhance their resistance to erosion and thermal shock. When Al₂O₃ is present in the refractory material, [Ce] in the molten steel reacts with Al₂O₃ to form CeAlO₃, gradually creating a cerium-containing rare earth aluminate layer. With increasing smelting time, [Ce] and [S] in the molten steel further react with CeAlO₃ to form an outer layer containing Ce₂O₂S, exhibiting dendritic growth. Simultaneously, the presence of Al₂O₃ also causes rare earth loss, severely impacting rare earth yield.
[0004] Domestic patent application number 202210242457.8 discloses a refractory material for a steel ladle used in rare earth steel smelting and its manufacturing method. The steel ladle includes a furnace body 1 and a slag line 2. The refractory material of the furnace body 1 is made of magnesium-calcium rare earth material, and the refractory material of the slag line 2 is made of magnesium-carbon rare earth material. The rare earth element is one or two of CeO2 and La2O3. The furnace body refractory material and the slag line refractory material developed by this invention have high erosion resistance.
[0005] However, the refractory materials for steel ladles disclosed in this patent and existing technologies simply involve introducing rare earth oxides into the refractory material to prepare refractory materials containing rare earth oxides. Currently, there is no evidence of using rare earth oxides and magnesium oxide to prepare rare earth-based fused magnesia raw materials through electrofusion, and then using these rare earth-based fused magnesia raw materials as a basis for preparing refractory materials required for rare earth steel smelting. Summary of the Invention
[0006] In view of the above analysis and in response to the shortcomings of the existing technology, the present invention provides an application of fused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, in order to solve the problem of erosion and loss of refractory materials by rare earths in the current rare earth steel smelting process.
[0007] The technical solution of this invention is:
[0008] The application of an electrofused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, wherein the rare earth steel contains lanthanum and / or cerium, and the ladle refractory material includes the furnace body and slag line.
[0009] The furnace body refractory material is made from fused magnesia-lanthanum / cerium-based refractory material and binder. By mass percentage, it includes 40%–50% fused magnesia-lanthanum / cerium sand with a particle size of 3–1 mm, 20%–25% fused magnesia-lanthanum / cerium sand with a particle size of 1–0.1 mm, 30%–50% fused magnesia-lanthanum / cerium sand with a particle size ≤0.088 mm, and an additional 4%–6% binder. The slag line refractory material is made from fused magnesia-lanthanum / cerium-based refractory material, flake graphite, phenolic resin, and antioxidant. By mass percentage, it includes 40%–50% fused magnesia-lanthanum / cerium sand with a particle size of 1–0.1 mm, 30%–50% fused magnesia-lanthanum / cerium sand with a particle size ≤0.088 mm, 10%–15% flake graphite, an additional 5%–7% phenolic resin, and 2%–6% antioxidant.
[0010] Furthermore, in the application of the above-mentioned fused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, the chemical composition of the fused magnesium lanthanum / cerium carbon-based refractory material includes, by mass percentage: MgO: 80-90%, La2O3: 0-20%, and CeO2: 0-20%.
[0011] Furthermore, in the application of the aforementioned fused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, the binder used in the furnace body refractory material is one of magnesium chloride, magnesium phosphate, or magnesium sulfate.
[0012] Furthermore, in the application of the aforementioned fused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, the flake graphite used in the slag line refractory is high-purity flake graphite with a purity ≥99.5% and a particle size ≤0.180mm; the phenolic resin is thermosetting, industrial grade, with a carbonization rate of 30-50%; and the antioxidant is at least one of metallic aluminum, metallic silicon, and metallic lanthanum with a purity ≥99.5% and a particle size range of ≤0.075mm.
[0013] Furthermore, in the application of the above-mentioned fused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, the preparation method of the furnace body refractory material is as follows: the raw materials are uniformly mixed according to the formula, pressed into green billets, and after drying, the green billets are subjected to high-temperature firing treatment at 1500-1650℃ to obtain the furnace body refractory material.
[0014] Furthermore, in the application of the above-mentioned fused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, the preparation method of the slag line refractory material is as follows: the raw materials are uniformly mixed according to the formula, pressed into green billets, dried, and then heat-treated at 200-300℃ to obtain the slag line refractory material.
[0015] Advantages and beneficial effects of the present invention:
[0016] 1. This invention uses fused magnesium lanthanum / cerium sand as the base material, and introduces rare earth oxides into the refractory material through electrofusion. This reduces the risk of rare earth oxides being washed into the steel by the molten steel, and even if they are washed into the molten steel, their content is small and they are eutectic with magnesium oxide, with a density much lower than that of the molten steel, so they can float.
[0017] 2. Refractory materials prepared using fused magnesium lanthanum / cerium-based materials, due to the presence of rare earth oxides in their raw materials, can inhibit the reaction between rare earth steel and refractory materials during direct contact with rare earth steel.
[0018] 3. Because the fused magnesium lanthanum / cerium sand in this invention has high thermal shock resistance and high corrosion resistance, the fused magnesium lanthanum / cerium-based refractory material prepared by it does not contain Al2O3, which greatly reduces the reaction between rare earth elements in rare earth steel and refractory materials, reduces the loss of rare earth elements, and improves the recovery rate of rare earth elements. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the longitudinal section of a steel ladle;
[0020] In the diagram, 1 represents the furnace body, and 2 represents the slag line. Detailed Implementation
[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following three examples are for illustrative purposes only and should not be used to limit the scope of the present invention.
[0022] This invention provides the application of an electrofused magnesium lanthanum / cerium-based refractory material in a ladle for smelting rare earth steel. The rare earth steel contains 0.005–0.1% Ce and 0.005–0.1% La by mass, which can be added separately or simultaneously. The refractory material in the ladle is arranged according to the distribution of the molten steel and top slag, such as… Figure 1 As shown, it is divided into two parts: furnace body 1 and slag line 2. The ladle is constructed in accordance with conventional construction methods.
[0023] The refractory material of furnace body 1 is made of fused magnesia-lanthanum / cerium-based refractory material and binder. By mass percentage, it includes 40% to 50% fused magnesia-lanthanum / cerium sand with a particle size of 3 to 1 mm, 20% to 25% fused magnesia-lanthanum / cerium sand with a particle size of 1 to 0.1 mm, 40% to 50% fused magnesia-lanthanum / cerium sand with a particle size ≤ 0.088 mm, and 4% to 6% binder. The binder is one of magnesium chloride, magnesium phosphate, or magnesium sulfate.
[0024] The slag line 2 refractory material uses fused magnesia-lanthanum / cerium-based refractory material, flake graphite, phenolic resin, and antioxidant as raw materials. By mass percentage, it comprises 40%–50% fused magnesia-lanthanum / cerium sand with a particle size of 1–0.1 mm, 30%–50% fused magnesia-lanthanum / cerium sand with a particle size ≤0.088 mm, 10%–15% flake graphite, 5%–7% phenolic resin, and 2%–6% antioxidant. The flake graphite used in the slag line refractory material is high-purity flake graphite with a purity ≥99.5% and a particle size ≤0.180 mm; the phenolic resin is thermosetting, industrial grade, with a carbonization rate of 30–50%; the antioxidant is at least one of metallic aluminum, metallic silicon, and metallic lanthanum, with a purity ≥99.5% and a particle size range ≤0.075 mm.
[0025] The chemical composition of the fused magnesium lanthanum / cerium carbon-based refractory material, by mass percentage, includes MgO: 80-90%, La2O3: 0-20%, and CeO2: 0-20%.
[0026] The method for preparing the furnace body refractory is as follows: the raw materials are mixed evenly according to the formula, pressed into green blanks, dried, and then subjected to high-temperature firing treatment at 1500-1650℃ to obtain the furnace body refractory.
[0027] The preparation method of the slag line refractory material is as follows: the raw materials are uniformly mixed according to the formula, pressed into green blanks, dried, and then heat-treated at 200-300℃ to obtain the slag line refractory material.
[0028] Example 1.
[0029] This embodiment describes the application of an electrofused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles. The ladle refractory material comprises two parts: the furnace body and the slag line. Rare earth steel is selected with lanthanum content of 0.06% by mass.
[0030] The furnace body refractory material is made from fused magnesia-lanthanum / cerium-based refractory material and binder. By mass percentage, it includes 40% fused magnesia-lanthanum sand with a particle size of 3-1 mm, 20% fused magnesia-lanthanum sand with a particle size of 1-0.1 mm, 40% fused magnesia-lanthanum sand with a particle size ≤0.088 mm, and an additional 5% binder, which is magnesium chloride. After the above raw materials are uniformly mixed, they are pressed into green blanks. After the green blanks are dried, they are subjected to high-temperature firing treatment at 1550℃ to obtain the furnace body refractory material.
[0031] The slag line refractory material is made from fused magnesia-lanthanum / cerium-based refractory material, flake graphite, phenolic resin, and antioxidants. By mass percentage, it includes 50% fused magnesia-lanthanum sand with a particle size of 1-0.1 mm, 40% fused magnesia-lanthanum sand with a particle size ≤0.088 mm, 10% flake graphite with a particle size ≤0.180 mm, plus 7% phenolic resin and 2% antioxidant lanthanum powder with a particle size range ≤0.075 mm. The above raw materials are uniformly mixed and pressed into green blanks. After drying, the green blanks are heat-treated at 220°C to obtain the slag line refractory material.
[0032] The chemical composition of the fused magnesium lanthanum / cerium-based refractory material comprises, by mass percentage, 90% MgO and 10% La2O3.
[0033] A comparative experiment on the erosion of rare earth steel molten steel and rare earth protective slag was conducted according to GB / T8931-2007 standard, comparing it with traditional steel ladle materials, aluminum-magnesium furnace body materials, and magnesium-aluminum-carbon slag wire materials. Samples of the rare earth steel were then analyzed after the experiments. The comparison showed that the erosion rate of the fused magnesium-lanthanum-based furnace body refractories and slag wire refractories decreased by an average of 12%, while the rare earth lanthanum recovery rate in the steel increased by 10%.
[0034] Example 2.
[0035] This embodiment describes the application of an electrofused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles. The ladle refractory material comprises two parts: the furnace body and the slag line. Rare earth cerium is selected and configured with lanthanum at a mass percentage of 0.06%.
[0036] The furnace body refractory material is made from fused magnesia-lanthanum / cerium-based refractory material and binder. By mass percentage, it includes 45% fused magnesia-cerium sand with a particle size of 3-1 mm, 20% fused magnesia-cerium sand with a particle size of 1-0.1 mm, 35% fused magnesia-cerium sand with a particle size ≤0.088 mm, and an additional 4% binder, which is magnesium sulfate. After the above raw materials are uniformly mixed, they are pressed into green blanks. After the green blanks are dried, they are subjected to high-temperature firing treatment at 1500℃ to obtain the furnace body refractory material.
[0037] The slag line refractory material is made from fused magnesia-lanthanum / cerium-based refractory material, flake graphite, phenolic resin, and antioxidants. By mass percentage, it includes 45% fused magnesia-cerium sand with a particle size of 1-0.1 mm, 45% fused magnesia-cerium sand with a particle size ≤0.088 mm, 10% flake graphite with a particle size ≤0.180 mm, plus 7% phenolic resin and 4% antioxidant cerium powder with a particle size range ≤0.075 mm. The above raw materials are uniformly mixed and pressed into green blanks. After drying, the green blanks are heat-treated at 200°C to obtain the slag line refractory material.
[0038] The chemical composition of the fused magnesium lanthanum / cerium-based refractory material comprises, by mass percentage, 90% MgO and 10% CeO2.
[0039] A comparative experiment on the erosion of rare earth steel molten steel and rare earth protective slag was conducted according to GB / T8931-2007 standard, comparing it with traditional steel ladle materials, aluminum-magnesium furnace body materials, and magnesium-aluminum-carbon slag wire materials. Samples of the rare earth steel were then analyzed after the experiments. The comparison showed that the erosion rate of the fused magnesium-cerium-based furnace body refractories and slag wire refractories decreased by an average of 10%, while the recovery rate of rare earth lanthanum in the steel increased by 15%.
[0040] Example 3.
[0041] This embodiment describes the application of an electrofused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles. The ladle refractory material comprises two parts: the furnace body and the slag line. Rare earth steel is selected with lanthanum and cerium at a mass percentage of 0.03%.
[0042] The furnace body refractory material is made from fused magnesia-lanthanum / cerium-based refractory material and binder. By mass percentage, it includes 40% fused magnesia-lanthanum / cerium sand with a particle size of 3-1 mm, 20% fused magnesia-lanthanum / cerium sand with a particle size of 1-0.1 mm, 40% fused magnesia-lanthanum / cerium sand with a particle size ≤0.088 mm, and an additional 5% binder, which is magnesium chloride. The above raw materials are uniformly mixed and pressed into green blanks. After drying, the green blanks are subjected to high-temperature firing treatment at 1550°C to obtain the furnace body refractory material.
[0043] The slag line refractory material is made from fused magnesium lanthanum / cerium-based refractory material, flake graphite, phenolic resin, and antioxidants. By mass percentage, it includes 50% fused magnesium lanthanum / cerium sand with a particle size of 1-0.1 mm, 40% fused magnesium lanthanum / cerium sand with a particle size ≤0.088 mm, 10% flake graphite with a particle size ≤0.180 mm, plus 7% phenolic resin and 3% antioxidants (aluminum, lanthanum powder, and cerium with a particle size range ≤0.075 mm). The above raw materials are uniformly mixed and pressed into green blanks. After drying, the green blanks are heat-treated at 220°C to obtain the slag line refractory material.
[0044] The chemical composition of the fused magnesium lanthanum / cerium-based refractory material comprises, by mass percentage: MgO: 85%, La2O3: 7.5%, and CeO2: 7.5%.
[0045] A comparative experiment on the erosion of rare earth steel molten steel and rare earth protective slag was conducted according to GB / T8931-2007 standard, comparing the erosion rates of the molten magnesium lanthanum-based furnace body material and the magnesia-alumina-carbon slag wire material with those of the traditional steel ladle material and the magnesia-alumina-carbon slag wire material. Samples of the rare earth steel were then analyzed. The comparison showed that the erosion rate of the molten magnesium lanthanum-based furnace body refractories and slag wire refractories decreased by an average of 16%, while the rare earth lanthanum recovery rate in the steel increased by 17%.
Claims
1. The application of an electrofused magnesium lanthanum / cerium-based refractory material in the smelting of rare earth steel ladles, characterized in that, The rare earth steel contains lanthanum and / or cerium, and the refractory material of the ladle includes the furnace body and slag line; The furnace body refractory material is made from fused magnesia-lanthanum / cerium-based refractory material and binder. By mass percentage, it includes 40%~50% fused magnesia-lanthanum / cerium sand with a particle size of 3~1mm, 20%~25% fused magnesia-lanthanum / cerium sand with a particle size of 1~0.1mm, 30%~50% fused magnesia-lanthanum / cerium sand with a particle size ≤0.088mm, plus 4%~6% binder. The slag line refractory material is made from fused magnesia-lanthanum / cerium-based refractory material, flake graphite, phenolic resin and antioxidant as raw materials. By mass percentage, it includes 40%~50% fused magnesia-lanthanum / cerium sand with a particle size of 1~0.1mm, 30%~50% fused magnesia-lanthanum / cerium sand with a particle size ≤0.088mm, 10%~15% flake graphite, plus 5%~7% phenolic resin and 2%~6% antioxidant. The flake graphite used in the slag line refractory material is high-purity flake graphite with a purity ≥99.5% and a particle size ≤0.180mm; the phenolic resin is thermosetting, industrial grade, with a carbonization rate of 30~50%; the antioxidant is at least one of metallic aluminum, metallic silicon, and metallic lanthanum with a purity ≥99.5% and a particle size range of ≤0.075mm. The preparation method of the slag line refractory material is as follows: the raw materials are uniformly mixed according to the formula, pressed into green blanks, and after drying, the green blanks are heat-treated at 200~300℃ to obtain the slag line refractory material. The chemical composition of the electrofused magnesium lanthanum / cerium-based refractory material, by mass percentage, includes MgO: 80-90%, La2O3: 0-20%, and CeO2: 0-20%.
2. The application of the fused magnesium lanthanum / cerium-based refractory material according to claim 1 in the smelting of rare earth steel ladles, characterized in that, The binder used in the furnace body refractory material is one of magnesium chloride, magnesium phosphate, or magnesium sulfate.
3. The application of an electrofused magnesium lanthanum / cerium-based refractory material according to claim 1 or 2 in the smelting of rare earth steel ladles, characterized in that, The method for preparing the furnace body refractory is as follows: the raw materials are mixed evenly according to the formula, pressed into green blanks, dried, and then subjected to high-temperature firing treatment at 1500~1650℃ to obtain the furnace body refractory.