Chromium-containing crucible and preparation method thereof

Abstract

The invention discloses a chromium-containing crucible and a preparation method thereof, and the chromium-containing crucible comprises the following raw material components in percentage by mass: 23-26% of white corundum; 29 to 31% of mullite; 13-15% of aluminum oxide; 1-3% of silica powder; 19 to 21% of tabular corundum; 5-7% of chromium oxide; 0.5 to 1.5 percent of an additive; the chromium-containing crucible prepared by the invention is longer in service life, and the service life of the chromium-containing crucible can be prolonged to 45 or more than 45 from the original 30; chromium oxide is introduced and the raw material ratio is optimized, so that the density of the crucible is remarkably improved, molten metal bonding is effectively prevented, and slag bonding is less during smelting; the bonding strength between the slag and the crucible wall is lower, and the slag is easier to clean.

Description

Technical Field

[0001] The invention belongs to the technical field of crucible preparation, and in particular relates to a chromium-containing crucible and a preparation method thereof. Background Art

[0002] Corundum crucible is mainly composed of porous molten alumina, which is hard and resistant to melting. Therefore, it is also called alumina crucible. It has excellent properties of high temperature resistance, rapid cooling and heating resistance, and chemical corrosion resistance, and is widely used in high temperature melting fields.

[0003] In the traditional preparation method, the raw materials used are often mullite, white corundum, alumina, etc. The resulting crucibles are often not dense enough, which causes the high-temperature molten metal to easily adhere to the inner wall of the crucible, causing the product to contain impurities, thereby affecting the quality of the product and greatly reducing the life of the crucible. Summary of the invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a chromium-containing crucible and a preparation method thereof, which effectively solves the problems raised in the above background.

[0005] To achieve the above object, the present invention provides the following technical solution: a chromium-containing crucible, comprising the following raw material components in mass percentage:

[0006] White corundum: 23-26%;

[0007] Mullite: 29-31%;

[0008] Alumina: 13-15%;

[0009] Silica powder: 1-3%;

[0010] Tabular corundum: 19-21%;

[0011] Chromium oxide: 5-7%;

[0012] Additives: 0.5-1.5%.

[0013] Preferably, the additive is silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0014] Preferably, a method for preparing a chromium-containing crucible comprises the following steps:

[0015] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0016] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0017] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0018] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0019] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at a temperature of 1400-1600°C in a reducing atmosphere to obtain a dense crucible product.

[0020] Preferably, in S5, the high temperature sintering time is 70-72 hours.

[0021] Preferably, in S1, the D50 particle size of the fine powder is 5-8 μm.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The chromium-containing crucible prepared by the present invention has a longer service life, which can be increased from 30 furnaces to 45 furnaces or more;

[0024] 2. The present invention significantly improves the density of the crucible by introducing chromium oxide and optimizing the raw material ratio, effectively preventing the adhesion of the molten metal, and reducing the adhesion of the slag during smelting;

[0025] 3. The bonding strength between the slag and the crucible wall is lower, and the slag is easier to clean. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] The present invention provides a chromium-containing crucible, comprising the following raw material components in percentage by weight:

[0028] White corundum: 23-26%;

[0029] Mullite: 29-31%;

[0030] Alumina: 13-15%;

[0031] Silica powder: 1-3%;

[0032] Tabular corundum: 19-21%;

[0033] Chromium oxide: 5-7%;

[0034] Additives: 0.5-1.5%.

[0035] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0036] A method for preparing a chromium-containing crucible comprises the following steps:

[0037] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0038] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0039] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0040] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0041] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at a temperature of 1400-1600°C in a reducing atmosphere to obtain a dense crucible product.

[0042] In S5 of this embodiment, the high temperature sintering time is 70-72 hours.

[0043] In S1 of this embodiment, the D50 particle size of the fine powder is 5-8 μm.

[0044] Embodiment 1:

[0045] A chromium-containing crucible comprises the following raw material components in percentage by weight:

[0046] White corundum: 25%;

[0047] Mullite: 30%;

[0048] Alumina: 14%;

[0049] Silica powder: 3%;

[0050] Tabular corundum: 20%;

[0051] Chromium oxide: 7%;

[0052] Additives: 1%.

[0053] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0054] The purity of chromium oxide is not less than 99%.

[0055] A method for preparing a chromium-containing crucible comprises the following steps:

[0056] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0057] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0058] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0059] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0060] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at 1500°C in a reducing atmosphere to obtain a dense crucible product.

[0061] In S5 of this embodiment, the high temperature sintering time is 70 hours.

[0062] In S1 of this embodiment, the D50 particle size of the fine powder is 6 μm.

[0063] Embodiment 2:

[0064] A chromium-containing crucible comprises the following raw material components in percentage by weight:

[0065] White corundum: 25%;

[0066] Mullite: 30%;

[0067] Alumina: 14%;

[0068] Silica powder: 3%;

[0069] Tabular corundum: 21%;

[0070] Chromium oxide: 6%;

[0071] Additives: 1%.

[0072] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0073] The purity of chromium oxide is not less than 99%.

[0074] A method for preparing a chromium-containing crucible comprises the following steps:

[0075] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0076] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0077] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0078] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0079] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at 1500°C in a reducing atmosphere to obtain a dense crucible product.

[0080] In S5 of this embodiment, the high temperature sintering time is 70 hours.

[0081] In S1 of this embodiment, the D50 particle size of the fine powder is 6 μm.

[0082] Embodiment 3:

[0083] A chromium-containing crucible comprises the following raw material components in percentage by weight:

[0084] White corundum: 25%;

[0085] Mullite: 30%;

[0086] Alumina: 14%;

[0087] Silica powder: 3%;

[0088] Tabular corundum: 22%;

[0089] Chromium oxide: 5%;

[0090] Additives: 1%.

[0091] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0092] The purity of chromium oxide is not less than 99%.

[0093] A method for preparing a chromium-containing crucible comprises the following steps:

[0094] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0095] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0096] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0097] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0098] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at 1500°C in a reducing atmosphere to obtain a dense crucible product.

[0099] In S5 of this embodiment, the high temperature sintering time is 70 hours.

[0100] In S1 of this embodiment, the D50 particle size of the fine powder is 6 μm.

[0101] Embodiment 4:

[0102] A chromium-containing crucible comprises the following raw material components in percentage by weight:

[0103] White corundum: 25%;

[0104] Mullite: 30%;

[0105] Alumina: 14%;

[0106] Silica powder: 3%;

[0107] Tabular corundum: 21%;

[0108] Chromium oxide: 6%;

[0109] Additives: 1%.

[0110] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0111] The purity of chromium oxide is not less than 99%.

[0112] A method for preparing a chromium-containing crucible comprises the following steps:

[0113] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0114] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0115] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0116] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0117] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at 1500°C in a reducing atmosphere to obtain a dense crucible product.

[0118] In S5 of this embodiment, the high temperature sintering time is 72 hours.

[0119] In S1 of this embodiment, the D50 particle size of the fine powder is 7 μm.

[0120] Embodiment 5:

[0121] A chromium-containing crucible comprises the following raw material components in percentage by weight:

[0122] White corundum: 25%;

[0123] Mullite: 30%;

[0124] Alumina: 14%;

[0125] Silica powder: 3%;

[0126] Tabular corundum: 21%;

[0127] Chromium oxide: 6%;

[0128] Additives: 1%.

[0129] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0130] The purity of chromium oxide is not less than 99%.

[0131] A method for preparing a chromium-containing crucible comprises the following steps:

[0132] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0133] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0134] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0135] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0136] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at 1500°C in a reducing atmosphere to obtain a dense crucible product.

[0137] In S5 of this embodiment, the high temperature sintering time is 70 hours.

[0138] In S1 of this embodiment, the D50 particle size of the fine powder is 7 μm.

[0139] Embodiment 6:

[0140] A chromium-containing crucible comprises the following raw material components in percentage by weight:

[0141] White corundum: 25%;

[0142] Mullite: 30%;

[0143] Alumina: 14%;

[0144] Silica powder: 3%;

[0145] Tabular corundum: 21%;

[0146] Chromium oxide: 6%;

[0147] Additives: 1%.

[0148] The additives in this embodiment are silica sol and sodium lignosulfonate in a mass ratio of 1:1.

[0149] The purity of chromium oxide is not less than 99%.

[0150] A method for preparing a chromium-containing crucible comprises the following steps:

[0151] S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state;

[0152] S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture;

[0153] S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape;

[0154] S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%;

[0155] S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at 1550°C in a reducing atmosphere to obtain a dense crucible product.

[0156] In S5 of this embodiment, the high temperature sintering time is 70-72 hours.

[0157] In S1 of this embodiment, the D50 particle size of the fine powder is 7 μm.

[0158] Comparative Example 1

[0159] A chromium-containing crucible comprises the following raw materials in mass fractions: white corundum: 35%; mullite: 30%; alumina: 20%; silicon micropowder: 2%; 2# mud: 2%; plate-shaped corundum: 10%; additives: 1%, and the rest is the same as in Example 1.

[0160] Comparative Example 2

[0161] A chromium-containing crucible comprises the following raw materials in mass fractions: white corundum: 25%; mullite: 30%; alumina: 14%; silicon micropowder: 3%; plate-shaped corundum: 27%; additives: 1%, and the rest is the same as in Example 1.

[0162] The above embodiments and comparative examples were subjected to performance tests, and the test results are shown in Table 1.

[0163] Table 1 Performance test values ​​of embodiments and comparative examples

[0164] Sample Bulk density g / cm3 Refractoriness ℃ Use temperature ℃ Example 1 3.5 185 ＞1650℃ Example 2 3.6 186 ＞1650℃ Example 3 3.4 183 ＞1650℃ Example 4 3.2 180 ＞1650℃ Example 5 3.3 182 ＞1650℃ Comparative Example 1 2.5 170 1550℃ Comparative Example 2 2.3 165 1510℃

[0165] Table 2 Crucible composition and content (wt%)

[0166] Sample Al2O3 SiO2 Fe2O3 CrO3 Example 2 87 8.6 0.1 5.1

[0167] The crucibles of Comparative Examples 1 and 2 were used to produce hydrogen storage alloys, and the service life of the crucibles was 30 furnaces. The service life of the crucible of Example 2 was more than 45 furnaces, and the maximum number of furnaces used was 52 furnaces.

[0168] It can be seen from the above table that the performance of the embodiment is better than that of the comparative example. The main reason may be that the addition of chromium oxide improves the fluidity of each component during high-temperature sintering, makes the molecular structure of the crucible denser, and improves the strength and hardness. Due to the dense structure, the erosion of the inner wall of the crucible by the high-temperature molten metal can be effectively reduced, and the crucible's resistance to thermal expansion and contraction is increased. Therefore, the high-temperature molten metal is not easy to adhere to the inner wall of the crucible.

[0169] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0170] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A chromium-containing crucible, characterized in that: The raw material components include the following mass percentages: White corundum: 23-26%; Mullite: 29-31%; Alumina: 13-15%; Silica powder: 1-3%; Tabular corundum: 19-21%; Chromium oxide: 5-7%; Additives: 0.5-1.5%.

2. A chromium-containing crucible according to claim 1, characterized in that: The additives are silica sol and sodium lignosulfonate in a mass ratio of 1:

1.

3. The method for preparing a chromium-containing crucible according to claim 1 or 2, characterized in that: The following steps are involved: S1, mixing and grinding: mixing the above raw materials according to the proportion and grinding them into a fine powder state; S2. Mixing ingredients: Add appropriate amount of water and additives to the ground fine powder, mix thoroughly to form a uniform mixture; S3, molding: putting the mixture into a mold, and through a vibration molding process, ensuring that the materials are closely arranged to form a crucible body of the desired shape; S4, drying: drying the formed crucible blank until the moisture content is no more than 0.5%; S5. High temperature sintering: Place the dried crucible blank in a high temperature furnace and sinter it at a temperature of 1400-1600°C in a reducing atmosphere to obtain a dense crucible product.

4. The method for preparing a chromium-containing crucible according to claim 3, characterized in that: In S5, the high temperature sintering time is 70-72 hours.

5. The method for preparing a chromium-containing crucible according to claim 3, characterized in that: In the S1, the D50 particle size of the fine powder is 5-8 μm.