A horizontal centrifugal casting method for quartz crucibles

Abstract

This invention relates to a horizontal centrifugal casting method for quartz crucibles, specifically in the field of quartz crucible technology, comprising the following steps: S1, starting the horizontal centrifugal casting equipment and controlling it to a first rotation speed, then controlling the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to be 1-10°, adding release material to the mold of the horizontal centrifugal casting equipment, and then performing vacuuming; S2, performing a first glass melt injection and a second glass melt injection into the mold, then controlling the axis of the horizontal centrifugal casting equipment to rotate parallel to the horizontal plane, then controlling the horizontal centrifugal casting equipment to a second rotation speed and performing a third glass melt injection, and then demolding to obtain the quartz crucible. The horizontal centrifugal casting method for quartz crucibles provided by this invention, through improvements to the process, helps to further improve the thickness uniformity of the obtained crucible, while further reducing the occurrence of bubble aggregation at the radius (R-angle), which is beneficial to improving the performance of the obtained quartz crucible.

Description

Technical Field

[0001] This invention relates to the field of quartz crucible technology, and more specifically to a horizontal centrifugal casting method for quartz crucibles. Background Technology

[0002] Currently, quartz crucibles are essential basic industrial materials for the photovoltaic industry in the fabrication of solar cells and the development of large-scale integrated circuits, and the industry is also moving towards larger diameters and longer lifespans. The inner layer of the quartz crucible needs to be in direct contact with high-purity molten silicon, and is generally a transparent layer with as few bubbles as possible to avoid crystal pulling defects caused by the rupture of bubbles on the surface of the quartz crucible. Currently, this structure of the quartz crucible is controlled using a vertical rotating mold vacuum method. Specifically, after quartz sand is layered and formed on the inner surface of the vertical mold, the centrifugal force generated by the rotation of the mold keeps the quartz sand adhering to the inner wall of the mold. Then, the quartz sand is melted using an electric arc method, and by combining different vacuum conditions, quartz crucibles with the desired bubble content are manufactured. However, this traditional method cannot avoid the problem of molten quartz glass movement caused by differences in centrifugal force at different locations. In particular, the quartz sand / molten quartz glass at the bottom of the mold is easily thrown to the radius (R) corner of the mold under greater centrifugal force, resulting in a thickness deviation where the bottom of the quartz crucible is too thin and the radius corner is too thick. At the same time, it also causes the problem of air bubbles accumulating on the surface of the crucible's radius corner, which is not only detrimental to the consistency of product dimensions, but also to the Czochralski process of single crystal silicon. Therefore, overcoming the centrifugal force of the mold is of great importance for manufacturing quartz crucibles with uniform thickness and fewer air bubbles in the radius corner.

[0003] Centrifugal casting is a special casting process, particularly suitable for the single-piece and batch production of cylindrical castings, and therefore has great potential for producing quartz crucibles of similar shapes. In horizontal centrifugal casting, the rotation axis is horizontal, so the centrifugal force (component force) on the liquid material on the inner wall of the rotating mold is parallel to the direction of gravity, effectively eliminating the movement phenomenon caused by excessive centrifugal force in vertical molds. Specifically, since the direction of centrifugal force always points from the center of curvature (inside the mold) to the outside of the mold, for the liquid material on the inner wall of the mold in horizontal centrifugal casting, the centrifugal force (component force) on the lower half is in the same direction as gravity, which makes it adhere more firmly to the mold wall. The centrifugal force (component force) on the upper half is in the opposite direction to gravity, and the centrifugal force (component force) is partially canceled by gravity, so it will not move due to a large centrifugal force. That is, the liquid material on the inner wall of the rotating mold will not undergo significant positional movement. This effectively overcomes the problem of molten quartz glass movement in vertical centrifugal casting. Compared with vertical centrifugal casting, it can improve the thickness uniformity of the quartz crucible at various positions and reduce the phenomenon of bubble accumulation on the surface of the R-corner of the quartz crucible.

[0004] For example, CN218893575U discloses a horizontal quartz crucible melting device, including a support, a mold with its central axis along the horizontal direction fixed on the support, a water-cooling jacket on the outer periphery of the mold, and an electrode lifting component with electrodes fixed on it.

[0005] However, when using existing horizontal quartz crucible melting equipment for centrifugal casting of quartz crucibles, it was found that there are still problems such as low thickness uniformity and bubble aggregation at the R-angle. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a horizontal centrifugal casting method for quartz crucibles, so as to solve the problems of low thickness uniformity and bubble aggregation at the R-angle found when performing centrifugal casting of quartz crucibles using a horizontal quartz crucible melting device.

[0007] To achieve this objective, the present invention adopts the following technical solution: This invention provides a horizontal centrifugal casting method for quartz crucibles, the horizontal centrifugal casting method comprising the following steps: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to be 1-10°. Add the release material into the mold of the horizontal centrifugal casting equipment and then perform vacuuming. S2. First and second glass melt injections are made into the mold. Then, the axial rotation of the horizontal centrifugal casting equipment is controlled to be parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to the second speed and a third glass melt injection is made. After demolding, a quartz crucible is obtained.

[0008] The horizontal centrifugal casting method for quartz crucibles provided by this invention improves the uniformity of crucible thickness by adopting a multi-feeding method, while also reducing the occurrence of bubble aggregation at the radius (R-angle), which is beneficial to improving the performance of the resulting quartz crucibles.

[0009] As a preferred embodiment of the present invention, the first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), and γ is the density of the quartz crucible (kg / m³). 3 .

[0010] As a preferred embodiment of the present invention, the release material includes quartz sand.

[0011] Preferably, the particle size of the quartz sand is 0.5-5 mm; Preferably, the purity of the quartz sand is ≥99.9%.

[0012] As a preferred technical solution of the present invention, the amount of quartz sand injected is such that it covers the inner surface of the mold to form a powder layer of 0.1-3 mm.

[0013] As a preferred technical solution of the present invention, the endpoint of the vacuuming is when the absolute vacuum degree of the mold is ≤0.05MPa.

[0014] As a preferred technical solution of the present invention, the first glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 8-10°, and 30-35% of the total amount of glass melt forming the quartz crucible is injected into the mold.

[0015] As a preferred technical solution of the present invention, the second glass liquid injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 4-5°, and 30-35% of the total amount of glass liquid forming the quartz crucible is injected into the mold.

[0016] As a preferred embodiment of the present invention, the second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), and γ is the density of the quartz crucible (kg / m³). 3 .

[0017] As a preferred embodiment of the present invention, the third glass liquid injection is to inject the remaining glass liquid into the mold.

[0018] As a preferred technical solution of the present invention, the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it during demolding is 1-5°.

[0019] Compared with existing technical solutions, the present invention has the following beneficial effects: (1) The method provided by the present invention uses a horizontal centrifugal casting process to neutralize the centrifugal force and gravity, reduce the movement of quartz glass liquid and bubbles at the bottom of the mold, and finally obtain a high-performance fully transparent quartz crucible with uniform size and thickness and no R-corner bubble aggregation.

[0020] (2) The gradient centrifugation method of adding quartz glass solution in multiple stages can better counteract the centrifugal force during the molding of quartz glass solution and eliminate air bubbles in quartz glass solution. At the same time, this also reduces the load and shear pressure on the mold caused by adding excessive quartz glass solution to the horizontal mold at one time, reduces the risk that the quartz glass solution cannot adhere tightly to the inner wall of the mold, and avoids the problem of the quartz crucible collapsing inward. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an exemplary horizontal centrifugal casting quartz crucible; Figure 2 This is a schematic diagram of the detection points in an embodiment of the present invention.

[0022] In the diagram: 1-drive shaft, 2-vacuum channel, 3-mold support, 4-mold, 5-outer shell, 6-feed port; α is the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane above it, and β is the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it.

[0023] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0024] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows: This embodiment provides a horizontal centrifugal casting method for quartz crucibles, the horizontal centrifugal casting method comprising the following steps: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to be 1-10°. Add the release material into the mold of the horizontal centrifugal casting equipment and then perform vacuuming. S2. First and second glass melt injections are made into the mold. Then, the axial rotation of the horizontal centrifugal casting equipment is controlled to be parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to the second speed and a third glass melt injection is made. After demolding, a quartz crucible is obtained.

[0025] In this invention, adding the quartz glass solution in multiple stages allows it to better adhere to the inner wall of the mold, thereby reducing the air bubble content and making the size and thickness of the quartz crucible more uniform with fewer air bubbles. At the same time, adding all the quartz glass solution at once would place an excessive load and shear pressure on the transverse mold. The sudden change in gravity would prevent the centripetal force provided by the mold from neutralizing the gravity in time. This is not only detrimental to neutralizing the centripetal force, but also easily causes the quartz crucible to collapse inward during molding. Therefore, adding the solution in three (or more) stages can help improve the performance and safety of the crucible.

[0026] In this invention, the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is controlled to be 1-10°, for example, it can be 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9° or 10°, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0027] In this invention, the axial direction of the horizontal centrifugal casting equipment is the same as the axial direction of the transmission shaft. The axial direction of the horizontal centrifugal casting equipment is parallel, that is, the transmission shaft is parallel to the horizontal plane.

[0028] For example, the horizontal centrifugal casting equipment used is such as Figure 1 As shown, the drive shaft 1 of the entire mold 4 is equipped with a vacuum pump to evacuate the inner cavity of the mold 4; a vacuum channel 2 is provided between the mold support 3 and the mold 4; the mold 4 is made of high-purity graphite or cast iron, the mold shell 5 is used to ensure the vacuum is achieved, the mold is supported by a support device so that it can be suspended vertically to the ground and can be rotated longitudinally by the drive shaft 1; the feed port 6 is used to feed reaction raw materials, such as quartz sand or quartz liquid, such as an external high-purity glass molten pool, which is pumped into the interior of the mold 4 by a pumping device, and the pipeline can move horizontally and vertically.

[0029] Among them, the use of quartz liquid can eliminate the traditional quartz sand preforming process and heat source supply method such as graphite electrodes, and instead use the method of directly pumping quartz glass liquid, which improves the production efficiency of quartz crucibles and avoids the potential carbon element pollution risk of quartz electrodes.

[0030] In this invention, an auxiliary heating device can also be installed inside the mold to heat the mold, preventing the quartz glass solution from solidifying too quickly and extending the molding time, such as direct heating or heat exchange.

[0031] In this invention, "above the horizontal plane" refers to a position above a certain horizontal plane, such as the horizontal plane where the axis of the drive shaft is located; correspondingly, "below the horizontal plane" refers to a position below the horizontal plane, and the angle between the axis of the horizontal centrifugal casting equipment and "above the horizontal plane" is _____. Figure 1 In the middle α, the angle between the axial direction of the horizontal centrifugal casting equipment and the upper horizontal plane is α. Figure 1 β in the middle.

[0032] Specifically, the first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), and γ is the density of the quartz crucible (kg / m³). 3 .

[0033] The quartz sand has a particle size of 0.5-5mm.

[0034] In this invention, the particle size range of the quartz sand is an aggregate of particles of any size within that range. It can be an aggregate of uniformly sized particles, or an aggregate of all particles within a certain range, such as an aggregate of uniformly sized particles with a particle size of 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. The particles are uniformly sized aggregates, or aggregates of all particles within the particle size range of 0.5-1 mm, or aggregates of all particles within the particle size range of 0.5-2 mm, or aggregates of all particles within the particle size range of 1-3 mm, or aggregates of all particles within the particle size range of 1.5-3.5 mm, or aggregates of all particles within the particle size range of 2-4 mm, or aggregates of all particles within the particle size range of 3-5 mm, or aggregates of all particles within the particle size range of 0.5-5 mm.

[0035] The release material includes quartz sand; other release materials besides quartz sand may also be used to separate the quartz crucible from the inner wall of the mold and remove the quartz crucible.

[0036] The purity of the quartz sand is ≥99.9%, for example, it can be 99.9%, 99.92%, 99.94%, 99.96%, 99.98%, 99.99%, or 99.999%, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0037] The amount of quartz sand injected is such that it covers the inner surface of the mold to form a powder layer of 0.1-3 mm. For example, it can be 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0038] The endpoint of the vacuuming is when the absolute vacuum degree of the mold is ≤0.05MPa. For example, it can be 0.05MPa, 0.04MPa, 0.03MPa, 0.02MPa, 0.01MPa, 0.005MPa or 0.001MPa, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0039] Wherein, the first glass melt injection is when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 8-10°, 30-35% of the total amount of glass melt forming the quartz crucible is injected into the mold. For example, it can be 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5%, 34%, 34.5% or 35%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0040] In this invention, the first glass melt injection is carried out at an angle of 8-10° between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane. For example, it can be 8°, 8.5°, 9°, 9.5° or 10°, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0041] The second glass melt injection refers to injecting 30-35% of the total amount of glass melt to form the quartz crucible into the mold when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 4-5°. For example, it can be 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5%, 34%, 34.5%, or 35%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0042] In this invention, the angle between the axial direction of the second glass melt injection device and the horizontal plane above it is 4-5°, for example, it can be 4°, 4.2°, 4.4°, 4.6°, 9.8° or 5°, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0043] When adding release material to the mold of the horizontal centrifugal casting equipment, the angle controlled is less than the angle controlled during the first and second glass melt injections. Therefore, the axial angle between the horizontal centrifugal casting equipment and the horizontal plane should be adjusted to the corresponding limited range during the first and second glass melt injections.

[0044] Wherein, the second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), and γ is the density of the quartz crucible (kg / m³). 3 .

[0045] In this invention, the outer diameter of the quartz crucible product refers to the diameter from the outer straight wall of the quartz crucible to the center, and the inner diameter of the quartz crucible product refers to the diameter from the inner straight wall of the quartz crucible to the center.

[0046] The third glass melt injection refers to injecting the remaining glass melt into the mold.

[0047] The SiO2 mass percentage content in the molten glass used in the casting process must be ≥99.99%, such as 99.99%, 99.991%, 99.992%, 99.994%, 99.996%, 99.998%, 99.999%, or 99.9999%, but not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0048] In the demolding process, the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below is 1-5°, for example, it can be 1°, 2°, 3°, 4° or 5°, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0049] In this invention, the maximum centrifugal force (MPa) that the quartz glass solution can withstand at the first and second rotational speeds is calculated, and the density of the quartz crucible (kg / m³) is also calculated. 3 The inherent performance parameters of the quartz glass solution and quartz crucible products can be obtained according to commonly used verification methods in the art. Among them, the mold inner diameter / m in the calculation of the first rotation speed can be designed according to conventional design requirements in the art combined with the dimensions of the obtained crucible. For example, the mold inner diameter is 10-25mm larger than the required outer diameter of the crucible.

[0050] Furthermore, to illustrate the excellent effects achievable by the horizontal centrifugal casting method for quartz crucibles provided by this invention, practical examples are used for explanation, as follows: Example 1 This embodiment provides a horizontal centrifugal casting method for a quartz crucible, wherein the target quartz crucible is designed with the following dimensions: a 24-inch crucible with an outer diameter of 610 mm and an inner diameter of 580 mm. The specific preparation process is as follows: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to 4°. Add quartz sand (particle size 2-4.5mm, purity 99.9%) to the mold of the horizontal centrifugal casting equipment. Then evacuate the mold until the absolute vacuum degree of the mold is 0.01MPa. S2. First and second glass liquid injections are made into the mold. Then, the axial rotation of the horizontal centrifugal casting equipment is controlled to be parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to the second speed and a third glass liquid injection is made. Then, the mold is demolded to obtain a quartz crucible. Wherein, the first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), chosen as 630 mm; P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160 MPa; and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The amount of quartz sand injected is such that it covers the inner surface of the mold to form a 2mm powder layer; The first glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 9.5°, injecting 32% of the total amount of glass melt into the mold to form the quartz crucible; The second glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 4.5°, injecting 32% of the total amount of glass melt into the mold to form the quartz crucible. The second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160MPa, and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The third glass melt injection is the injection of the remaining glass melt into the mold; The angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it during the demolding process is 4°.

[0051] The specifications of the obtained quartz crucible are detailed in Table 1.

[0052] Example 2 This embodiment provides a horizontal centrifugal casting method for a quartz crucible, wherein the target quartz crucible is designed with the following dimensions: 28 inches, outer diameter 710 mm, and inner diameter 680 mm. The specific preparation process is as follows: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to 8°. Add quartz sand (particle size 0.5-3mm, purity 99.9%) to the mold of the horizontal centrifugal casting equipment. Then evacuate the mold until the absolute vacuum degree of the mold is 0.05MPa. S2. First and second glass liquid injections are made into the mold. Then, the axial rotation of the horizontal centrifugal casting equipment is controlled to be parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to the second speed and a third glass liquid injection is made. Then, the mold is demolded to obtain a quartz crucible. Wherein, the first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), chosen as 730 mm; P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160 MPa; and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The amount of quartz sand injected is such that it covers the inner surface of the mold to form a 1mm powder layer; The first glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 9°, injecting 34% of the total amount of glass melt into the mold to form the quartz crucible. The second glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 4°, injecting 34% of the total amount of glass melt into the mold to form the quartz crucible. The second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160MPa, and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The third glass melt injection is the injection of the remaining glass melt into the mold; The angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it during the demolding process is 2°.

[0053] The specifications of the obtained quartz crucible are detailed in Table 1.

[0054] Example 3 This embodiment provides a horizontal centrifugal casting method for a quartz crucible, wherein the target quartz crucible is designed with the following dimensions: 32 inches, outer diameter 810 mm, and inner diameter 780 mm. The specific preparation process is as follows: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to be 10°. Add quartz sand (particle size 2-4mm, purity 99.99%) to the mold of the horizontal centrifugal casting equipment. Then, evacuate the mold until the absolute vacuum degree of the mold is 0.03MPa. S2. First and second glass liquid injections are made into the mold. Then, the axial rotation of the horizontal centrifugal casting equipment is controlled to be parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to the second speed and a third glass liquid injection is made. Then, the mold is demolded to obtain a quartz crucible. Wherein, the first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), which is chosen to be 160MPa, and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The amount of quartz sand injected is such that it covers the inner surface of the mold to form a 3mm powder layer; The first glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 8°, injecting 30% of the total amount of glass melt into the mold to form the quartz crucible. The second glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 5°, injecting 35% of the total amount of glass melt into the mold to form the quartz crucible. The second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160MPa, and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The third glass melt injection is the injection of the remaining glass melt into the mold; The angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it during demolding is 1°.

[0055] The specifications of the obtained quartz crucible are detailed in Table 1.

[0056] Example 4 This embodiment provides a horizontal centrifugal casting method for a quartz crucible, wherein the target quartz crucible is designed with the following dimensions: 36 inches, outer diameter 915 mm, and inner diameter 875 mm. The specific preparation process is as follows: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to 1°. Add quartz sand (particle size 1-3mm, purity 99.99%) to the mold of the horizontal centrifugal casting equipment. Then, evacuate the mold until the absolute vacuum degree of the mold is 0.04MPa. S2. First and second glass liquid injections are made into the mold. Then, the axial rotation of the horizontal centrifugal casting equipment is controlled to be parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to the second speed and a third glass liquid injection is made. Then, the mold is demolded to obtain a quartz crucible. Wherein, the first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), chosen as 925 mm; P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160 MPa; and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The amount of quartz sand injected is such that it covers the inner surface of the mold with a powder layer of 0.1 mm. The first glass melt injection is carried out when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 10°, injecting 35% of the total amount of glass melt into the mold to form the quartz crucible; The second glass melt injection is performed when the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 4°, injecting 30% of the total amount of glass melt into the mold to form the quartz crucible. The second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), chosen as 160MPa, and γ is the density of the quartz crucible (kg / m³). 3 The selected value is 2.2 kg / m³. 3 ; The third glass melt injection is the injection of the remaining glass melt into the mold; The angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it during demolding is 5°.

[0057] The specifications of the obtained quartz crucible are detailed in Table 1.

[0058] Comparative Example 1 The only difference from Example 1 is that the first glass melt injection is performed when the axial angle between the horizontal plane and the horizontal plane of the horizontal centrifugal casting equipment is 5°, injecting 32% of the total amount of glass melt to form the quartz crucible into the mold. The index parameters of the resulting quartz crucible are detailed in Table 1.

[0059] Comparative Example 2 The only difference from Example 1 is that the second glass melt injection is performed when the axial angle between the horizontal plane and the horizontal plane of the horizontal centrifugal casting equipment is 8°, injecting 32% of the total amount of glass melt to form the quartz crucible into the mold. The index parameters of the resulting quartz crucible are detailed in Table 1.

[0060] Comparative Example 3 The only difference from Example 1 is that the angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane is 0° in both the first and second glass melt injections. The performance parameters of the resulting quartz crucible are detailed in Table 1.

[0061] The thickness uniformity test parameter for the quartz crucible is calculated based on the standard deviation of thickness data from commonly used thickness test points in this field. The dimensional uniformity test parameter is calculated based on the standard deviation of commonly used dimensional data in this field. The test points are as follows: Figure 2 As shown in the figure, W1 and W2 are the corresponding thickness detection points, and D is the corresponding size detection point. In the above embodiment, the size uniformity is calculated by measuring the diameter parameter corresponding to D 50 times on the crucible product. The 50 measuring points are evenly distributed around the circumference. The thickness uniformity is calculated by measuring point W2 by measuring 50 points on the plane corresponding to the detection position. The 50 measuring points are evenly distributed around the circumference. The R-corner bubble aggregation is detected by a transparent layer thickness gauge. The specific test location is... Figure 2 The number of bubbles in the circumferential direction at the position corresponding to R in the middle.

[0062] Table 1 As shown in Table 1, the solution provided by the present invention, by improving the process and adopting a multiple feeding method, helps to further improve the thickness uniformity of the obtained crucible, and at the same time further reduces the occurrence of bubble aggregation in the R-angle, which is beneficial to improving the performance of the obtained quartz crucible.

[0063] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0064] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0065] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0066] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A horizontal centrifugal casting method for a quartz crucible, characterized in that, The horizontal centrifugal casting method includes the following steps: S1. Start the horizontal centrifugal casting equipment and control it to the first speed. Then control the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane to be 1-10°. Add the release material into the mold of the horizontal centrifugal casting equipment and then perform vacuuming. S2. First and second glass melt injections are performed into the mold. The first glass melt injection is performed when the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane is 8-10°, injecting 30-35% of the total glass melt into the mold to form the quartz crucible. The second glass melt injection is performed when the angle between the axis of the horizontal centrifugal casting equipment and the horizontal plane is 4-5°, injecting 30-35% of the total glass melt into the mold to form the quartz crucible. Then, the axis of the horizontal centrifugal casting equipment is controlled to rotate until it is parallel to the horizontal plane. Then, the horizontal centrifugal casting equipment is controlled to a second speed and a third glass melt injection is performed. Finally, the mold is demolded to obtain the quartz crucible.

2. The horizontal centrifugal casting method as described in claim 1, characterized in that, The first rotational speed N1 is calculated according to the following formula (I): (I) In the formula, R is the inner diameter of the mold (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), and γ is the density of the quartz crucible (kg / m³). 3 .

3. The horizontal centrifugal casting method as described in claim 1, characterized in that, The release material includes quartz sand.

4. The horizontal centrifugal casting method as described in claim 3, characterized in that, The particle size of the quartz sand is 0.5-5mm.

5. The horizontal centrifugal casting method as described in claim 3, characterized in that, The purity of the quartz sand is ≥99.9%.

6. The horizontal centrifugal casting method as described in claim 3, characterized in that, The amount of quartz sand injected is such that it covers the inner surface of the mold with a powder layer of 0.1-3 mm.

7. The horizontal centrifugal casting method as described in claim 1, characterized in that, The vacuuming process ends when the absolute vacuum level of the mold is ≤0.05MPa.

8. The horizontal centrifugal casting method as described in claim 1, characterized in that, The second rotational speed N2 is calculated according to the following formula (II): (II) In the formula, R 外 R is the outer diameter of the quartz crucible product in meters (m). 内 γ is the inner diameter of the quartz crucible product (m), P is the maximum centrifugal force that the quartz glass solution can withstand (MPa), and γ is the density of the quartz crucible (kg / m³). 3 .

9. The horizontal centrifugal casting method as described in claim 1, characterized in that, The third glass melt injection refers to injecting the remaining glass melt into the mold.

10. The horizontal centrifugal casting method as described in claim 1, characterized in that, The angle between the axial direction of the horizontal centrifugal casting equipment and the horizontal plane below it during demolding is controlled to be 1-5°.

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