A method of manufacturing an alumina crucible

Abstract

This invention belongs to the field of crucible preparation technology, specifically relating to a method for preparing an alumina crucible, comprising the following steps: Step 1: preparing a mixed solution and placing it in a ball mill; Step 2: obtaining a composite alumina slurry in the ball mill; Step 3: preparing composite alumina powder from the composite alumina slurry; Step 4: adding a binder to the composite alumina powder to obtain an alumina mixture; Step 5: molding the alumina mixture using a mold to obtain a crucible blank, wherein the mold forming process is a double-sided suction process. Compared with the prior art, the advantages and positive effects of this invention are: the double-sided suction process adsorbs fine particles in the material onto the product surface, while coarse particles are located in the middle layer of the product, thereby greatly improving the surface roughness of the finished alumina crucible, making the size of the alumina crucible more controllable, eliminating the need for a wax removal process, and effectively reducing the risk of the surface of the finished alumina crucible peeling off during use.

Description

Technical Field

[0001] This invention belongs to the field of crucible preparation technology, and specifically relates to a method for preparing an alumina crucible. Background Technology

[0002] Alumina crucibles are crucibles made of alumina sand. They are mainly used for high-temperature smelting, experimental analysis, and chemical reactions. Alumina crucibles are resistant to high temperatures and have excellent chemical stability. They also have excellent corrosion resistance and do not contaminate the molten material. In short, alumina crucibles are a non-toxic, harmless, and environmentally friendly material.

[0003] Existing methods for preparing alumina crucibles often require the use of paraffin wax as a binder, followed by a wax removal process, which is quite complex. Furthermore, the surface of the finished alumina crucibles often has pits and is quite rough, which can even lead to the peeling of the outer skin after prolonged use. Therefore, there is an urgent need for a method to prepare alumina crucibles with fewer pits and a smoother surface. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing an alumina crucible.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing an alumina crucible, comprising the following steps:

[0006] Step 1: Prepare the mixed solution and put it into the ball mill;

[0007] Step 2: Obtain composite alumina slurry in the ball mill;

[0008] Step 3: Preparation of composite alumina powder from composite alumina slurry;

[0009] Step 4: Add the composite alumina powder to the binder to obtain an alumina mixture;

[0010] Step 5: The alumina mixture is molded to obtain a crucible blank. The mold forming process is a double-sided suction process.

[0011] Preferably, the binder in step four includes water and clay.

[0012] Preferably, after obtaining the crucible blank in step five, the crucible blank is dried naturally, and then a firing process is carried out to obtain the finished crucible.

[0013] Preferably, the double-sided suction process in step five involves injecting the alumina mixture into a mold under low pressure, and the mold then drains excess moisture.

[0014] Preferably, the mold is a resin mold or a plaster mold.

[0015] Preferably, the forming pressure is controlled by hydraulic thrust during the mold forming process.

[0016] Preferably, after the composite alumina powder and binder are injected into the resin mold, they are pressurized by a press.

[0017] Preferably, step one includes weighing lanthanum nitrate, cerium nitrate, and yttrium nitrate, dissolving them in deionized water to prepare a mixed solution, and then placing the mixed solution into a ball mill.

[0018] Preferably, step two includes adding deionized water, alumina powder, and ball milling media to the mixed solution, mixing them evenly, and then ball milling to obtain a composite alumina slurry.

[0019] Preferably, step three includes placing the composite alumina slurry into a sintering furnace for drying and calcination, drying at 180 degrees Celsius for two hours, then raising the temperature to 600 degrees Celsius by increasing the temperature by eight degrees Celsius per minute, holding at that temperature for two hours, and then cooling it with the furnace.

[0020] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0021] (1) The mold forming process is a double-sided suction process. The double-sided suction process adsorbs fine particles in the material onto the surface of the product, while coarse particles are located in the middle layer of the product. This greatly improves the surface roughness of the finished alumina crucible, and the size of the alumina crucible is more controllable. It can effectively reduce the risk of the surface of the finished alumina crucible peeling off during use and effectively prevent the material from wetting the alumina crucible during use.

[0022] (2) The binder includes water and clay. The binder is a mixture of water and clay. There is no need for the wax removal process. The mixing method has been changed from using paraffin wax as the binder to using water and clay as the binder, which reduces the wax removal process, simplifies the steps, and makes the process simple and repeatable, which is beneficial to industrial production.

[0023] (3) The mold is a resin mold or a plaster mold. Compared with the commonly used stainless steel mold, the resin mold or plaster mold has a better double-sided slurry absorption effect, which can better ensure that the surface roughness of the alumina crucible after processing is smaller and the forming effect is better. The alumina mixture is injected into the mold in a low-pressure manner. The excess water in the alumina mixture is discharged through the water permeability of the mold to achieve the purpose of strengthening the alumina crucible blank. The strengthened alumina crucible greatly reduces the risk of the surface peeling off during use.

[0024] (4) After obtaining the crucible blank, the crucible blank is dried naturally and then fired to obtain the finished crucible. The firing process improves the physical properties of the crucible blank, such as hardness, density, and strength, and optimizes the physical properties, forming a fired product with certain hardness and strength and small surface roughness. At the same time, the firing process can effectively reduce the risk of the surface of the finished alumina crucible peeling off during use and effectively prevent the material from wetting the alumina crucible during use.

[0025] (5) The forming pressure is controlled by hydraulic thrust during mold forming. Compared with the pneumatic die casting process, the hydraulic control of forming pressure can ensure that the surface roughness of alumina produced in different batches is relatively small. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below:

[0027] Figure 1 This is a flowchart of the preparation method for an alumina crucible. Detailed Implementation

[0028] To better understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0030] Example 1

[0031] The following is combined with Figure 1 Please provide a detailed explanation of the preparation method for the alumina crucible, such as... Figure 1 As shown, a method for preparing an alumina crucible includes the following steps:

[0032] Step 1: Prepare the mixed solution and put it into the ball mill;

[0033] Step 2: Obtain composite alumina slurry in the ball mill;

[0034] Step 3: Preparation of composite alumina powder from composite alumina slurry;

[0035] Step 4: Add the composite alumina powder to the binder to obtain an alumina mixture;

[0036] Step 5: The alumina mixture is molded to obtain a crucible blank. The mold forming process is a double-sided suction process.

[0037] In step four, the binder consists of water and clay, and the binder is a mixture of water and clay.

[0038] After obtaining the crucible blank in step five, the crucible blank is dried naturally, and then a firing process is carried out to obtain the finished crucible.

[0039] Firing involves heating raw materials at high temperatures to induce physical or chemical changes, forming specific chemical structures that improve physical properties such as hardness, density, and strength. The temperature and residence time in the firing chamber are key factors, and different materials and production requirements necessitate different parameter settings. During the heating process, the raw materials undergo chemical changes, forming new crystal structures and fusing particles together, thereby optimizing physical properties and resulting in fired products with a certain degree of hardness and strength.

[0040] In step five, the double-sided suction process involves injecting the alumina mixture into the mold under low pressure, allowing the mold to expel excess moisture.

[0041] The mold is a resin mold.

[0042] In mold forming, hydraulic thrust is used to control the forming pressure. Existing alumina crucible manufacturing processes often employ pneumatic die casting, using compressed air. However, the pressure of this compressed air is generally difficult to control precisely. As the number of formed alumina crucibles increases and the remaining alumina mixture in the hopper changes, differences in internal structure arise between crucibles formed earlier and later within the same hopper. For example, under full compressed air pressure in the early stages, air bubbles can be effectively expelled. Later, as the compressed air pressure decreases, air cannot be expelled in time, resulting in air trapped inside the product. This leads to significant differences in surface roughness between different batches of alumina crucibles. By using hydraulic thrust to control the forming pressure, the differences in internal structure between early and later formed alumina crucibles can be effectively minimized, thus ensuring similar surface roughness across different batches.

[0043] After the composite alumina powder and binder are injected into the resin mold, they are pressurized by a press.

[0044] Step one involves weighing lanthanum nitrate, cerium nitrate, and yttrium nitrate, dissolving them in deionized water to prepare a mixed solution, and then placing the mixed solution into a ball mill.

[0045] Step two involves adding deionized water, alumina powder, and ball milling media to the mixed solution, mixing them evenly, and then ball milling to obtain a composite alumina slurry.

[0046] Step 3 involves placing the composite alumina slurry into a sintering furnace for drying and calcination. The slurry is dried at 180 degrees Celsius for two hours, then heated to 600 degrees Celsius at a rate of 8 degrees Celsius per minute, held at that temperature for two hours, and then cooled with the furnace.

[0047] The resin mold using the double-sided suction process can ensure that the molded alumina crucible has a small surface roughness while maintaining water absorption.

[0048] The ball milling media consists of alumina spherical particles, which ensures uniform mixing and prevents the introduction of other impurities during ball milling.

[0049] Example 2

[0050] The difference between this embodiment and Embodiment 1 is that the mold is a plaster mold.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method of producing an alumina crucible, characterized by, Includes the following steps: Step 1: Prepare the mixed solution and put it into the ball mill; Step 2: Obtain composite alumina slurry in the ball mill; Step 3: Preparation of composite alumina powder from composite alumina slurry; Step 4: Add the composite alumina powder to the binder to obtain an alumina mixture; Step 5: The alumina mixture is molded to obtain a crucible blank. The mold forming process is a double-sided suction process. The adhesive mentioned in step four includes water and clay; The double-sided suction process described in step five involves injecting the alumina mixture into a mold under low pressure, and the mold then drains excess water. The mold is a resin mold or a plaster mold; The forming pressure is controlled by hydraulic thrust during the mold forming process; After the composite alumina powder and binder are injected into the resin mold, they are pressurized by a press.

2. The method of claim 1, wherein: After obtaining the crucible blank in step five, the crucible blank is dried naturally, and then a firing process is carried out to obtain the finished crucible.

3. The method of claim 1, wherein: Step one involves weighing lanthanum nitrate, cerium nitrate, and yttrium nitrate, dissolving them in deionized water to prepare a mixed solution, and then placing the mixed solution into a ball mill.

4. The method for preparing an alumina crucible according to claim 1, characterized in that: Step two involves adding deionized water, alumina powder, and ball milling media to the mixed solution, mixing them evenly, and then ball milling to obtain a composite alumina slurry.

5. The method for preparing an alumina crucible according to claim 1, characterized in that: Step 3 includes placing the composite alumina slurry into a sintering furnace for drying and calcination. The slurry is dried at 180 degrees Celsius for two hours, then heated to 600 degrees Celsius at a rate of 8 degrees Celsius per minute, held at that temperature for two hours, and then cooled with the furnace.

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