Vanadium-resistant refractory

Abstract

The present application relates to the field of refractory material, and particularly to a kind of anti-vanadium erosion refractory material, the chemical general formula of the refractory material is: (Mg a Ca b Sr c Ba 1‑a‑b‑c ) x (V d Nb e Ta f Mn 1‑d‑e‑f )2O x+5 , its crystal structure belongs to trigonal system;With adjustable component ratio, wherein 2≤x≤3, 0≤a≤0.1, 0.8≤b≤1, 0≤c≤0.1, 0.9≤d≤1, 0≤e≤0.05, 0≤f≤0.05.The present application can effectively improve the anti-vanadium erosion performance of the material by introducing vanadium-containing compounds into the refractory material, the component ratio of the refractory material and the replaceability of the precursor make it have better adaptability and flexibility to meet the requirements of different industrial equipment.

Description

Technical Field

[0001] This invention relates to the field of refractory materials, specifically to a vanadium-resistant refractory material. Background Technology

[0002] V₂O₅ is an important upstream product in the production of vanadium-nitrogen alloys and is widely used in chemical, aerospace, and other fields. However, current industrial V₂O₅ production requires heating in a melting furnace, and the corrosion of refractory materials by molten V₂O₅ is a serious problem. Traditional furnace lining materials such as clay bricks and chrome corundum bricks are prone to severe corrosion under the influence of high-temperature liquid V₂O₅, resulting in short furnace lining service life and frequent refractory replacements, increasing production costs. Furthermore, refractory spalling reduces the purity of the final product and affects yield. Studies have shown that chemical corrosion and physical erosion by molten oxides are the main causes of severe furnace lining corrosion.

[0003] Vanadium melting furnaces can utilize a variety of refractory materials, such as traditional silica bricks (SiO2), fused cast alumina (Al2O3), chromium corundum bricks (Cr2O3-Al2O3), fused cast mullite (Al2O3-SiO2), magnesium chromium spinel (MgCr2O4), magnesium aluminum spinel (MgAl2O4), and magnesia-carbon bricks (MgO-C). Currently, the working lining material for melting furnaces used to prepare V2O5 is mainly high-alumina refractory material, whose main phases are corundum, mullite, and a glassy phase. Because high-alumina bricks react with V2O5 at high temperatures to form low-melting-point substances, there are issues with their service life.

[0004] Vanadium can form oxides in different valence states under different temperature and oxygen partial pressure conditions. V₂O₃ has a melting point of approximately 2243 K (1970 °C), V₂O₄ forms a refractory binary system with other oxides, while V₂O₅ is a stable phase with a melting point of approximately 953 K (680 °C). The initial liquid phase formation temperature between V₂O₅ and Al₂O₃ is approximately 913 K (640 °C), allowing V₂O₅ to react rapidly and corrode refractory materials at the furnace operating temperature.

[0005] Vanadium primarily damages alkaline refractories through erosion of the bonding phase. V₂O₅ penetrates deeply into high-alumina bricks, causing them to deteriorate; these bricks are mainly eroded by melting and penetration. Magnesia-chromium (MgAl₂O₄) spinel refractories exhibit strong resistance to erosion and penetration by molten V₂O₅; however, the MgO within them reacts with V₂O₅ to form MgV₂O₆, reducing their corrosion resistance. Magnesia-carbon (MgO-C) bricks form a decarburized layer under vanadium impregnation conditions. If ineffective sintering results in a loose structure and poor bonding strength of this decarburized layer, making the brick susceptible to erosion and peeling damage from the molten pool.

[0006] Therefore, there is a need for a new type of vanadium-resistant refractory material for use as the lining of melting furnaces, in order to reduce the number of furnace repairs, lower production costs, and improve the purity and yield of the final product. Summary of the Invention

[0007] In view of the problems mentioned in the background art, the purpose of the present invention is to provide a vanadium-resistant refractory material. By including vanadium compounds in the refractory material, the vanadium erosion resistance of the material can be effectively improved. The composition ratio and the replaceability of the precursor of the refractory material make it more adaptable and flexible to meet the requirements of different industrial equipment.

[0008] The technical solution provided by this invention is: a vanadium-resistant refractory material, wherein the general chemical formula of the refractory material is:

[0009] (Mg a Ca b Sr c Ba 1-a-b-c ) x (V d Nb e Ta f Mn 1-d-e-f )2O x+5 Its crystal structure belongs to the trigonal crystal system;

[0010] It has adjustable component ratios, where 2≤x≤3, 0≤a≤0.1, 0.8≤b≤1, 0≤c≤0.1, 0.9≤d≤1, 0≤e≤0.05, and 0≤f≤0.05.

[0011] Furthermore, the precursors include, but are not limited to, calcium compounds, vanadium compounds, and oxides, wherein the calcium compounds include calcium hydroxide and calcium carbonate, and the vanadium compounds include vanadates and ammonium vanadate.

[0012] Furthermore, the composition ratio of divalent and pentavalent metal elements and oxygen in the refractory material can be optimized according to the sintering temperature and the final application of the material.

[0013] Furthermore, the composition ratio of the refractory material can be characterized and verified by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy.

[0014] Furthermore, the refractory material also includes other suitable additives, including ceramic fibers and reinforcing particles, to further improve the physical and mechanical properties of the material.

[0015] Furthermore, the refractory material exists in block, sheet, granular, coating or other forms to adapt to various application scenarios.

[0016] Furthermore, the refractory material is synthesized via a solid-state reaction method.

[0017] Furthermore, the refractory material is subjected to sintering, hot pressing, or other suitable processes to enhance its density and mechanical strength.

[0018] Furthermore, the refractory material is used to resist vanadium corrosion. The refractory material has excellent high temperature resistance and can be used stably in high temperature environments of 1000℃ to 1400℃. It is suitable for high temperature industrial equipment, including but not limited to steel furnaces, oil refining furnaces, and chemical reactors.

[0019] The beneficial effects of this invention are: it proposes a new approach to synthesizing vanadium-resistant refractory bricks by introducing vanadium-containing compounds. Since V already occupies lattice sites, when liquid V₂O₅ comes into contact with it, only a dynamic equilibrium V ion exchange occurs, without the formation of a new phase through chemical reaction. Therefore, it possesses excellent vanadium corrosion resistance.

[0020] In practical applications, the component ratio can be flexibly adjusted according to specific industrial equipment and process requirements to obtain the best material performance. Adjusting the ratio between different precursors can control the structure and interaction of the material, thereby achieving the best combination of materials. This flexibility makes the refractory material of the present invention have broad application potential in different industrial fields.

[0021] The vanadium-resistant refractory material disclosed in this invention has a variety of advantages, including but not limited to high-temperature stability, vanadium erosion resistance and flexible adjustability. This refractory material can be used in various high-temperature industrial equipment, such as steel furnaces, oil refining furnaces, chemical reactors, etc., to protect the equipment from vanadium erosion damage.

[0022] Therefore, the vanadium-resistant refractory material provided by the present invention has the following advantages:

[0023] 1. Excellent resistance to vanadium corrosion: Through reasonable composition design and control, the refractory material can effectively resist the erosion of liquid V2O5 and extend the service life of the vanadium melting furnace.

[0024] 2. Reduced production costs: Extended service life of refractory materials reduces the frequency of refractory replacement, lowers maintenance and replacement costs, and thus reduces production costs.

[0025] 3. Improve product quality: The excellent properties of refractory materials can prevent refractory spalling and structural damage, reduce impurities and contamination, and improve the purity and yield of the final product. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of XRD measurement values ​​in Embodiment 1 of the present invention.

[0027] Figure 2These are schematic diagrams of the dense block structure of Embodiments 1 and 2 of the present invention.

[0028] Figure 3 This is a schematic diagram of XRD measurement values ​​in Embodiment 2 of the present invention. Detailed Implementation

[0029] The present invention is illustrated below with specific embodiments, which are not intended to limit the scope of the invention.

[0030] Example 1:

[0031] The present invention provides a method for preparing the material, comprising the following steps:

[0032] 1) Weighing materials: according to the general formula Mg 0.01 Ca 2.97 Sr 0.01 Ba 0.01 To determine the stoichiometric ratio of V2O8, weigh high-purity MgCO3, CaCO3, SrCO3, BaCO3, and V2O5 in sequence, and weigh an appropriate amount of flux.

[0033] 2) Place the powder obtained in step 1) into an agate mortar, add an appropriate amount of alcohol and grind for 20-40 minutes. After it dries, scrape off the powder adhering to the mortar wall and dry grind for 10-30 minutes. Then place it in a high-temperature alumina crucible.

[0034] 3) Place the high-temperature alumina crucible in a box furnace and set the program for pre-firing. Heat to 600℃ at a heating rate of 5-10℃ / min and hold for 2-6 hours. Cool to room temperature with the furnace. Take out the sample and place it in a ball mill jar for ball milling for 4 hours.

[0035] 4) Measure the XRD, and the results are as follows: Figure 1 As shown;

[0036] 5) Fill the ball-milled powder from step 3) into a custom-made mold coated with a layer of lubricant. Then place the mold into a tablet press and increase the pressure to about 10 MPa. Maintain this pressure for 1 minute to achieve high compaction of the powder and form a dense structure with a blocky structure, such as... Figure 2 As shown;

[0037] 6) Transfer the solid block from step 5) back to the high-temperature alumina crucible and place it in a box furnace. Heat it to 1300℃ and calcine it at high temperature for 3-10 hours. Then cool it to 800℃ at a cooling rate of 5-10℃ / minute and then cool it to room temperature with the furnace.

[0038] 7) Test the vanadium corrosion resistance of the block at 1300℃. The specific steps are as follows: fill the central depression of the block obtained in step 6) with V2O5 powder, place it in a high-temperature furnace, heat it to 1300℃ and keep it at that temperature for 4 hours. After cooling with the furnace, take out the block, cut it vertically and measure the depth of V2O5 erosion.

[0039] In step 1) of the preparation method of the vanadium-resistant material of the present invention, the flux can be at least one of alkali metal chloride, B2O3, and H3BO3. The amount of flux used is 1 wt% relative to the total weight of the raw materials.

[0040] Steps 2) and 6) of the preparation method of the vanadium-resistant material described in this invention can significantly improve the purity of the synthesized sample.

[0041] Example 2:

[0042] Weighing materials: according to the general formula Ca2(V 0.95 Nb 0.02 Ta 0.02 Mn 0.01 The stoichiometric ratio of 2O7 is determined by weighing high-purity CaCO3, V2O5, Nb2O5, Ta2O5, and MnO2 in sequence, and then weighing an appropriate amount of flux.

[0043] Everything else is the same as in Example 1, except that the XRD pattern is as follows: Figure 3 As shown.

[0044] Comparative Example 1

[0045] Commercial silica bricks were processed into the block material shape shown in the examples;

[0046] The specific steps for testing the vanadium corrosion resistance of the block at 1300℃ are as follows: fill the central depression of the block with V2O5 powder, place it in a high-temperature furnace, heat it to 1300℃ and keep it at that temperature for 4 hours, and after cooling it with the furnace, take out the block, cut it vertically and measure the depth of V2O5 erosion.

[0047] Comparative Example 2

[0048] Commercial high-alumina bricks were processed into the block material shape shown in the embodiments;

[0049] The test of the block's resistance to vanadium corrosion at 1300℃ was conducted by filling the central depression of the block with V2O5 powder, placing it in a high-temperature furnace, heating it to 1300℃ and holding it there for 4 hours, cooling it with the furnace, removing the block, cutting it vertically, and measuring the depth of V2O5 corrosion.

[0050] Table 1: Results of Vanadium Erosion Experiment

[0051] Vanadium erosion depth Example 1 <1mm Example 2 1mm Comparative Example 1 >5mm Comparative Example 2 >5mm

[0052] By measuring the vanadium erosion depth of Comparative Examples 1, 2, 1, and 2, it was found that: the V2O5 erosion depth measured in Example 1 was <1 mm, the V2O5 erosion depth measured in Example 2 was 1 mm, the V2O5 erosion depth measured in Example 3 was >5 mm, and the V2O5 erosion depth measured in Example 4 was >5 mm. It can be seen that the vanadium erosion depth of Examples 1 and 2 is much lower than that of Comparative Examples 1 and 2.

[0053] The vanadium-resistant refractory material provided by this invention has broad application prospects, and its technical effects and economic benefits are significant. The preparation method of this refractory material is simple and feasible, with relatively low cost, and can be conveniently applied to industrial fields such as vanadium melting furnaces, thereby promoting the development of related industries.

[0054] Furthermore, the vanadium-resistant refractory material of this invention can be further optimized and improved according to specific needs. By adjusting the ratio and formulation of the core protective component and the expanded component, more refractory material combinations can be explored while ensuring vanadium resistance, in order to meet the needs of different industrial sectors for refractory materials.

[0055] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A vanadium-resistant refractory material, characterized in that, The method for preparing the refractory material includes the following steps: 1) Weighing materials: according to the general formula Mg 0.01 Ca 2.97 Sr 0.01 Ba 0.01 The stoichiometric ratio of V2O8 is determined by weighing high-purity MgCO3, CaCO3, SrCO3, BaCO3, and V2O5 in sequence, and weighing an appropriate amount of flux. The flux is at least one of alkali metal chloride, B2O3, and H3BO3, and the amount of flux used is 1 wt% relative to the total weight of the raw materials. 2) Place the powder obtained in step 1) into an agate mortar, add an appropriate amount of alcohol and grind for 20-40 minutes. After it dries, scrape off the powder adhering to the mortar wall, dry grind for 10-30 minutes, and then place it in a high-temperature alumina crucible. 3) Place the high-temperature alumina crucible in a box furnace and set the program for pre-firing. Heat to 600℃ at a heating rate of 5-10℃ / min and hold for 2-6 hours. Cool to room temperature with the furnace. Take out the sample and place it in a ball mill jar for ball milling for 4 hours. 4) Fill the ball-milled powder from step 3) into a custom mold coated with a layer of lubricant, then place the mold into a tablet press and increase the pressure to 10 MPa. Maintain this pressure for 1 minute to achieve high compaction of the powder and form a dense structure with a blocky structure. 5) Transfer the solid block from step 4) back to the high-temperature alumina crucible and place it in a box furnace. Heat it to 1300℃ and calcine it at high temperature for 3-10 hours. Then cool it to 800℃ at a cooling rate of 5-10℃ / minute and then cool it to room temperature with the furnace.

2. A vanadium-resistant refractory material, characterized in that, The method for preparing the refractory material includes the following steps: 1) Weighing materials: according to the general formula Ca2(V 0.95 Nb 0.02 Ta 0.02 Mn 0.01 To determine the stoichiometric ratio of 2O7, weigh high-purity CaCO3, V2O5, Nb2O5, Ta2O5, and MnO2 in sequence, and weigh an appropriate amount of flux; the flux is at least one of alkali metal chloride, B2O3, and H3BO3, and the amount of flux used is 1 wt% relative to the total weight of the raw materials. 2) Place the powder obtained in step 1) into an agate mortar, add an appropriate amount of alcohol and grind for 20-40 minutes. After it dries, scrape off the powder adhering to the mortar wall, dry grind for 10-30 minutes, and then place it in a high-temperature alumina crucible. 3) Place the high-temperature alumina crucible in a box furnace and set the program for pre-firing. Heat to 600℃ at a heating rate of 5-10℃ / min and hold for 2-6 hours. Cool to room temperature with the furnace. Take out the sample and place it in a ball mill jar for ball milling for 4 hours. 4) Fill the ball-milled powder from step 3) into a custom mold coated with a layer of lubricant, then place the mold into a tablet press and increase the pressure to 10 MPa. Maintain this pressure for 1 minute to achieve high compaction of the powder and form a dense structure with a blocky structure. 5) Transfer the solid block from step 4) back to the high-temperature alumina crucible and place it in a box furnace. Heat it to 1300℃ and calcine it at high temperature for 3-10 hours. Then cool it to 800℃ at a cooling rate of 5-10℃ / minute and then cool it to room temperature with the furnace.

3. A vanadium-resistant refractory material as described in claim 1 or 2, characterized in that, The refractory material is used to resist vanadium corrosion. It has excellent high temperature resistance and can be used stably in high temperature environments of 1000℃ to 1400℃, making it suitable for high temperature industrial equipment.

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