Purification method of high-purity quartz sand for quartz crucible and quartz crucible
By pre-screening, selective grinding, screening and drying of natural quartz sand, high-purity quartz sand suitable for quartz crucible production is purified, which solves the problem of irregular shapes and sharp edges of quartz sand in the existing technology. It solves the problems of crucible quality and qualification rate, achieves tighter quartz sand accumulation and lower air inclusion rate, and improves crucible quality and production efficiency.
Patent Information
- Application Number
- CN202411476454.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-01-21
AI Technical Summary
In the prior art, high-purity quartz sand used in the production of quartz crucibles has irregular shapes and sharp edges, resulting in poor accumulation of quartz sand, and then serious defects such as large air bubbles appear during the melting process, affecting the crucible quality and production pass rate.
By pre-screening, selective grinding, screening and drying the natural quartz sand raw materials, high-purity quartz sand suitable for quartz crucible production is purified. The specific steps include grinding quartz sand of different particle sizes with different intensities, and removing unsuitable particles through screening, and finally obtain high-purity quartz sand with rounded grain shape and uniform particle size.
Through the purified high-purity quartz sand, the quartz sand is packed more closely and the amount of air contained is smaller, which reduces the risk of large bubble defects in the crucible during the melting process and improves the quality of the crucible and the production pass rate.
Smart Images
Figure CN119330567A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of quartz crucible manufacturing materials, and in particular to a method for purifying high-purity quartz sand for a quartz crucible and the quartz crucible. Background Art
[0002] Quartz crucibles are key components of photovoltaic single crystal furnaces and consumable vessels for pulling large-diameter single crystal silicon. They are primarily used to hold molten silicon and form the crystal ingots needed for subsequent processes. The primary raw material used in quartz crucible production is high-purity quartz sand. Depending on the size and type of crucible, each crucible can consume tens or even hundreds of kilograms of high-purity quartz sand. With the rapid development of the semiconductor industry, the demand for quartz crucibles is also gradually increasing, and therefore, the demand for high-purity quartz sand is also increasing. In the prior art, the main source of high-purity quartz sand used in crucible production is natural quartz sand. Since natural quartz sand is made by crushing quartz crystal ore, it has obvious sharp edges formed by fracture, and most of the particles are irregular in shape. If there are a large number of quartz sand particles with sharp edges and irregular shapes in the quartz sand used to produce quartz crucibles, the quartz sand will not be stacked tightly enough, which will lead to serious defects such as large bubbles in the melting process of quartz crucible production, seriously affecting the quality of the quartz crucible and the production pass rate. Therefore, there is an urgent need for a technology that can purify quartz sand for quartz crucible production. Summary of the Invention
[0003] In view of this, it is necessary to provide a method for purifying high-purity quartz sand for a quartz crucible and a quartz crucible.
[0004] According to one aspect of the present invention, a method for purifying high-purity quartz sand for quartz crucibles is provided, comprising the following steps: S1. Pre-screening: S10, pre-screening the natural quartz sand raw material to be purified according to three particle sizes of +200µm, -200µm +50µm, and -50µm, to obtain three particle size samples of +200µm, -200µm +50µm, and -50µm; S11. Discard the -50µm particle size sample and keep the +200µm and -200µm +50µm particle size samples; S2, Selective Grinding: S20, performing high-intensity grinding on the ore sample with a particle size of +200µm to obtain first quartz sand particles; S21, grinding the -200µm +50µm particle size ore sample at a relatively low intensity to obtain second quartz sand particles; S3, screening: S30, mixing the first quartz sand particles and the second quartz sand particles to obtain third quartz sand particles; S31, screening the third quartz sand particles, removing the quartz sand with a particle size of -50 µm and leaving the quartz sand with a particle size of +50 µm, to obtain fourth quartz sand particles; S4, drying: The fourth quartz sand particles are dried to obtain high-purity quartz sand for quartz crucible.
[0005] Preferably, before step S1, the following steps are further included: S0, Primary Election: S00, sampling: Uniformly sampling natural quartz sand raw materials to obtain raw material samples; S01. Polarizing microscope observation: The morphology and particle shape of the raw material sample are observed using a polarizing microscope to obtain the particle shape and morphology of the raw material sample; S02, laser particle size analyzer particle size analysis: The particle size of the raw material sample is analyzed by a laser particle size analyzer to obtain the particle size distribution of the raw material sample; S03. Judgment: Based on the particle shape and particle size distribution of the obtained raw material sample, it is determined whether the raw material needs to be purified; if the raw material sample has round particles and the content of the -200µm +50µm particle size is greater than or equal to 80%, it is determined that the above-mentioned natural quartz sand raw material does not need to be purified; otherwise, it is determined that the above-mentioned natural quartz sand raw material needs to be purified.
[0006] Preferably, in step S20, the high-intensity grinding is performed on the +200µm particle size ore sample, and the grinding parameters adopted are: grinding speed 150-250r / min, grinding time 60-90min, grinding concentration 60-70%, and the grinding medium is one of zirconium balls or steel balls, and the diameter of the zirconium balls or steel balls is 1mm-10mm.
[0007] Preferably, in step S21, the -200µm + 50µm particle size ore sample is subjected to lower intensity grinding, and the grinding parameters adopted are: grinding speed 50-150r / min, grinding time 5-60min, grinding concentration 40-60%, and the grinding medium is one of zirconium balls or steel balls, and the diameter of the zirconium balls or steel balls is 1mm-10mm.
[0008] According to another aspect of the present invention, a quartz crucible is provided, which is prepared by high-purity quartz sand for quartz crucible obtained by any of the above methods for purifying high-purity quartz sand for quartz crucible.
[0009] The above-mentioned method for purifying high-purity quartz sand for quartz crucibles first screens the natural quartz sand raw material to be purified according to the particle size and discards the tailings that are not suitable for crucible production; secondly, the natural quartz sand raw materials of different particle sizes are subjected to targeted grinding under different conditions, so that the natural quartz sand raw materials of different particle sizes are ground and shaped with different intensities; compared with the natural quartz sand raw materials for crucible production that have not been purified in the prior art, the quartz sand raw materials purified by the present invention have greatly reduced irregular particles, no longer obvious particle edges and corners, the particle shape becomes rounded, and the particle size distribution is more uniform; at the same time, because the present invention performs targeted grinding under different conditions for natural quartz sand raw materials of different particle sizes, while the input quartz sand particles are better shaped, the production efficiency is also improved and the raw material loss rate is reduced; The above-mentioned quartz crucible is prepared by using high-purity quartz sand obtained by the method for purifying high-purity quartz sand for quartz crucibles provided by the present invention. Compared with the prior art, the high-purity quartz sand particles used are less angular, more rounded, and have a more uniform particle size distribution. During production, the quartz sand is more densely packed and the amount of entrained air is smaller, thereby reducing the risk of large bubble defects in the crucible during the melting process, improving the quality of the crucible, and improving the qualified rate of crucible production. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 The present invention provides a flow chart of the method for purifying high-purity quartz sand for quartz crucibles.
[0011] Figure 2 The particle shape and morphology of the raw material sample in the preliminary selection stage in Example 1 of the present invention, as well as the particle shape and morphology of the high-purity quartz sand obtained after purification.
[0012] Figure 3 The particle shape and morphology of the raw material sample in the preliminary selection stage in Example 2 of the present invention, as well as the particle shape and morphology of the high-purity quartz sand obtained after purification.
[0013] Figure 4 The particle shape and morphology of the raw material sample in the preliminary selection stage in Example 3 of the present invention, as well as the particle shape and morphology of the high-purity quartz sand obtained after purification.
[0014] Figure 5 The particle shape and morphology of the raw material sample in the preliminary selection stage in Example 4 of the present invention, as well as the particle shape and morphology of the high-purity quartz sand obtained after purification.
[0015] Figure 6 The particle shape and morphology of the raw material sample in the preliminary selection stage in Example 5 of the present invention, as well as the particle shape and morphology of the high-purity quartz sand obtained after purification.
[0016] Figure 7The particle shape and morphology of the raw material sample in the preliminary selection stage in Example 6 of the present invention, as well as the particle shape and morphology of the high-purity quartz sand obtained after purification.
[0017] Figure 8 This is a sampling picture of a quartz crucible sliced and sampled using the high-purity quartz sand purified in Example 1 in an embodiment of the present invention.
[0018] Figure 9 This is a sampling picture of the quartz crucible slices sampled after using the same batch of unpurified natural quartz sand raw material as in Example 1 to prepare the quartz crucible in the present invention. DETAILED DESCRIPTION
[0019] The technical solutions and technical effects of the embodiments of the present invention are further elaborated below in conjunction with the accompanying drawings of the present invention.
[0020] See Figure 1 As shown, in a typical embodiment of the present invention, a method for purifying high-purity quartz sand for quartz crucible is provided, comprising the following steps: S1. Pre-screening: S10, pre-screening the natural quartz sand raw material to be purified according to three particle sizes of +200µm, -200µm +50µm, and -50µm, to obtain three particle size samples of +200µm, -200µm +50µm, and -50µm; The natural quartz sand raw materials to be purified are pre-screened according to the above three particle sizes to prepare for subsequent selective grinding. The corresponding grinding conditions are selected for natural quartz sand raw materials of different particle sizes. Among them, +200µm indicates particles with a particle size greater than 200µm, -200µm +50µm indicates particles with a particle size greater than 50µm and less than 200µm, and -50µm indicates particles less than 50µm. S11. Discard the -50µm particle size sample and keep the +200µm and -200µm +50µm particle size samples. Particles with a size of less than 50µm are too small to easily generate dust during the grinding process and crucible production process. Therefore, they are screened out before selective grinding, so that only particles with a size of +50µm are retained in the raw materials for selective grinding. S2, Selective Grinding: S20, performing high-intensity grinding on the ore sample with a particle size of +200µm to obtain first quartz sand particles; S21. Grinding the -200µm +50µm particle size ore sample at a lower intensity to obtain a second quartz sand particle. Since larger particles of quartz sand raw material have a greater hardness, while smaller particles of quartz sand raw material have a lower hardness, grinding the +200µm particle size ore sample and the -200µm +50µm particle size ore sample at different intensities can ensure production efficiency and reduce loss rate while ensuring the effect of grinding and shaping. S3, screening: S30, mixing the first quartz sand particles and the second quartz sand particles to obtain third quartz sand particles; S31, screening the third quartz sand particles to remove the -50 µm quartz sand and retain the +50 µm quartz sand, thereby obtaining fourth quartz sand particles; through the above screening, the -50 µm quartz sand is removed as tailings, leaving the +50 µm quartz sand with a rounded shape and uniform particle size; S4, drying: The fourth quartz sand particles are dried to obtain high-purity quartz sand for quartz crucible.
[0021] Furthermore, before step S1, the following steps are also included: S0, Primary Election: S00, sampling: Uniformly sampling natural quartz sand raw materials to obtain raw material samples; S01. Polarizing microscope observation: The morphology and particle shape of the raw material sample are observed using a polarizing microscope to obtain the particle shape and morphology of the raw material sample; S02, laser particle size analyzer particle size analysis: The particle size of the raw material sample is analyzed by a laser particle size analyzer to obtain the particle size distribution of the raw material sample; S03. Judgment: Based on the particle shape and particle size distribution of the obtained raw material sample, it is determined whether the raw material needs to be purified; if the raw material sample has round particles and the content of the -200µm +50µm particle size is greater than or equal to 80%, it is determined that the above-mentioned natural quartz sand raw material does not need to be purified; otherwise, it is determined that the above-mentioned natural quartz sand raw material needs to be purified.
[0022] Through the above preliminary selection, the particle shape of the sample is observed by polarizing microscope, and the particle size distribution of the sample is analyzed by laser particle size analyzer, and the natural quartz sand raw materials that need to be purified are selected; for natural quartz sand raw materials with round particles and a particle size content of -200µm +50µm greater than or equal to 80%, the conditions for quartz crucible production are met, so no subsequent grinding is required and they can be put into production directly; for natural quartz sand raw materials with less round particles and a particle size content of -200µm +50µm less than 80%, if they are directly put into production without subsequent grinding and screening, large bubbles will be generated during the crucible production process, so they need to undergo subsequent grinding and screening before being put into production.
[0023] Furthermore, in step S20, the +200µm particle size ore sample is subjected to high-intensity grinding, and the grinding parameters adopted are: grinding speed 150-250r / min, grinding time 60-90min, grinding concentration 60-70%, and the grinding medium is one of zirconium balls or steel balls, and the diameter of the zirconium balls or steel balls is 1mm-10mm.
[0024] Furthermore, in step S21, the -200µm + 50µm particle size ore sample is subjected to lower intensity grinding, and the grinding parameters adopted are: grinding speed 50-150r / min, grinding time 5-60min, grinding concentration 40-60%, and the grinding medium is one of zirconium balls or steel balls, and the diameter of the zirconium balls or steel balls is 1mm-10mm.
[0025] The beneficial effects of the present invention will be further described in detail below with reference to comparative examples and specific embodiments.
[0026] Example 1 to Example 6 The high-purity quartz sand for quartz crucible is prepared by the method for purifying high-purity quartz sand for quartz crucible provided by the present invention. The particle shape and morphology of the raw material sample in the preliminary selection stage are shown in FIG. Figures 2 to 7 The other parameters in the preparation process are shown in Table 1. The quartz crucible obtained after purification is made of high-purity quartz sand, and its particle shape and morphology are shown in Table 1. Figures 2 to 7 As shown; and the quartz crucible obtained by purification in Example 1 is prepared with high-purity quartz sand, and the prepared quartz crucible is sliced to obtain Figure 8 The sampling pictures shown; Comparative Example The quartz crucible was prepared by using the same batch of unpurified natural quartz sand as in Example 1. The quartz crucible was sliced to obtain the following: Figure 9 The sampling pictures shown; Table 1
[0027] By comparing the particle shape and morphology of the raw material samples in the preliminary selection stage and the particle shape and morphology of the high-purity quartz sand for quartz crucibles obtained after purification in the above Examples 1 to 6, it can be seen that compared with the unpurified natural quartz sand raw material for crucible production, the quartz sand raw material after purification by the present invention has greatly reduced irregular particles, no longer obvious particle edges, rounded particles, and more uniform particle size distribution.
[0028] and through Figure 8 and Figure 9 From the comparison, it can be seen that the quartz crucible prepared by using the unpurified natural quartz sand raw material has obvious large bubbles with a length of about 5 cm, while the quartz crucible prepared by using the quartz sand purified by the method of the present invention has no large bubbles at all in its slices; therefore, compared with the prior art, the quartz crucible prepared by using the high-purity quartz sand for quartz crucible purification method provided by the present invention has no obvious edges and corners, the particles are more rounded, and the particle size distribution is more uniform. During production, the quartz sand is more densely stacked and the amount of entrained air is smaller, which reduces the risk of large bubble defects in the crucible during the melting process, improves the quality of the crucible, and improves the qualified rate of crucible production.
[0029] The above disclosure is only a preferred embodiment of the present invention, and it is certainly not intended to limit the scope of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.
Claims
1. A method for purifying high-purity quartz sand for quartz crucible, characterized in that: The following steps are involved: S1. Pre-screening: S10, pre-screening the natural quartz sand raw material to be purified according to three particle sizes of +200µm, -200µm +50µm and -50µm to obtain three particle size samples of +200µm, -200µm +50µm and -50µm; S11, discard the -50µm particle size sample, and keep the +200µm and -200µm +50µm particle size samples; S2, Selective Grinding: S20, grinding the ore sample with a particle size of +200µm at a relatively high intensity to obtain first quartz sand particles; S21, grinding the -200µm +50µm particle size ore sample at a relatively low intensity to obtain second quartz sand particles; S3, Screening: S30, mixing the first quartz sand particles and the second quartz sand particles to obtain third quartz sand particles; S31, screening the third quartz sand particles, removing the quartz sand with a particle size of -50 µm, leaving the quartz sand with a particle size of +50 µm, and obtaining fourth quartz sand particles; S4, drying: The fourth quartz sand particles are dried to obtain high-purity quartz sand for a quartz crucible.
2. The method for purifying high-purity quartz sand for quartz crucible according to claim 1, characterized in that: Before step S1, the method further includes the following steps: S0, Primary Election: S00, Sampling: Uniformly sampling natural quartz sand raw materials to obtain raw material samples; S01. Polarizing microscope observation: The morphology and particle shape of the raw material sample are observed by using a polarizing microscope to obtain the particle shape and morphology of the raw material sample; S02, laser particle size analyzer particle size analysis: The particle size of the raw material sample is analyzed by a laser particle size analyzer to obtain the particle size distribution of the raw material sample; S03. Judgment: According to the particle shape and particle size distribution of the obtained raw material sample, it is judged whether the raw material needs to be purified; if the particle shape of the raw material sample is round and the content of the -200µm +50µm particle size is greater than or equal to 80%, it is judged that the above-mentioned natural quartz sand raw material does not need to be purified, otherwise it is judged that the above-mentioned natural quartz sand raw material needs to be purified.
3. The method for purifying high-purity quartz sand for quartz crucible according to claim 1, characterized in that: In step S20, the +200µm particle size ore sample is subjected to high-intensity grinding, and the grinding parameters adopted are: grinding speed 150-250r / min, grinding time 60-90min, grinding concentration 60-70%, and the grinding medium is one of zirconium balls or steel balls, and the diameter of the zirconium balls or steel balls is 1mm-10mm.
4. The method for purifying high-purity quartz sand for quartz crucible according to claim 1, characterized in that: In step S21, the -200µm +50µm particle size ore sample is subjected to relatively low intensity grinding, and the grinding parameters adopted are: grinding speed 50-150r / min, grinding time 5-60min, grinding concentration 40-60%, and the grinding medium is one of zirconium balls or steel balls, and the diameter of the zirconium balls or steel balls is 1mm-10mm.
5. A quartz crucible, characterized in that: The quartz crucible is prepared by using the high-purity quartz sand obtained by the method for purifying high-purity quartz sand for quartz crucible as claimed in any one of claims 1 to 4.