Method for recycling used waste quartz boat / quartz bar / quartz plate according to quality

Abstract

The invention relates to a method for recycling and recycling used waste quartz boats / quartz bars / quartz plates according to quality, which comprises the following steps: cleaning the used waste quartz boats / quartz bars / quartz plates with water, drying, carrying out multi-dimensional mechanical fine polishing to remove surface erosion layers, and carrying out acid treatment to obtain regenerated high-purity quartz boats / quartz bars / quartz plates. Further, the regenerated high-purity quartz boat / quartz bar / quartz plate is subjected to low-shear crushing and then subjected to acid treatment, and a high-purity quartz sand product is obtained. According to the method, closed-loop regeneration from waste quartz boats / bars / plates to high-purity quartz materials is achieved, efficient separation of the materials is achieved through a multi-stage separation technology, 4N-stage high-purity quartz boats / bars / plates and high-purity quartz sand products with complete structures can be obtained, the impurity content is low, and the method is suitable for industrial production. And the recycling high-value material utilization of the used waste quartz boat / bar / plate is realized, and the method has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of high-value material utilization technology of solid waste resource utilization, specifically involving a method for recycling and regenerating waste quartz boats / quartz rods / quartz plates after use. Background Technology

[0002] High-purity quartz ore has been listed as the 174th legally recognized mineral, highlighting the strategic importance of high-end quartz and its products in economic and social development. The entire high-purity quartz industry chain is receiving significant attention. Therefore, the effective recycling and efficient utilization of waste is a key task, which can promote the high-value resource utilization of various solid wastes in industries such as semiconductors.

[0003] High-purity quartz boats are crucial carriers in the semiconductor industry, playing a vital role in wafer fabrication and thin-film deposition. The global semiconductor manufacturing industry generates approximately 150 million waste quartz boats annually, but the overall utilization rate of this solid waste remains low. Currently, the main methods are direct disposal, landfilling, or simple crushing for use as ordinary quartz. Research has found that the surface layer of discarded quartz boats contains strategic metals such as tin and indium, while the inner SiO2 layer retains high purity. Summary of the Invention

[0004] The problem the invention aims to solve

[0005] Under the high-temperature corrosion, chemical atmosphere erosion, and ion migration effects of semiconductor manufacturing processes, waste quartz boats, rods, and plates easily form an erosion layer enriched with elements such as Sn, In, B, and P on their surface. This leads to heterogeneity, structural distortion, and microcrack propagation in the quartz matrix, making it difficult to reuse directly. Traditional chemical cleaning or mechanical polishing processes suffer from problems such as incomplete removal of the erosion layer, severe surface damage rendering the material unusable, decreased quartz purity, and high energy consumption.

[0006] Meanwhile, the quartz particles obtained by crushing waste quartz boats / quartz rods / quartz plates often contain lattice distortion, inclusion impurities, and surface contamination, which cannot meet the stringent requirements of high-purity quartz sand for purity (≥99.99%), particle size distribution, and structural integrity in fields such as semiconductors and photovoltaics.

[0007] Therefore, there is an urgent need for a systematic solution that can simultaneously regenerate the macroscopic structure of quartz boats / quartz rods / quartz plates and precisely remove microscopic impurities, enabling the full-process recycling of waste quartz boats / quartz rods / quartz plates to high-purity quartz boats / quartz rods / quartz plates and quartz sand. This solution would overcome technical bottlenecks such as product surface damage leading to unusability during the recycling process, difficulty in purity control, difficulty in interface separation, high energy consumption, and environmental pollution.

[0008] Solution for solving the problem

[0009] To address the aforementioned issues, an integrated high-purity quartz synergistic regeneration technology system combining "multi-dimensional fine polishing and intelligent separation" was developed. Based on a systematic study of the surface composition and interface structure of waste quartz boats / rods / slabs, a synergistic regeneration system integrating multi-dimensional mechanical fine polishing, directional exfoliation, and intelligent separation was established. Through precise control of the interaction between the eroded layer and the substrate interface, efficient separation and removal between layers were achieved, avoiding surface damage to quartz boats / rods / slabs as in traditional processes. This allows used quartz boats / rods / slabs to be recycled while maintaining structural integrity, yielding reusable high-purity quartz boats / rods / slabs.

[0010] Furthermore, an integrated high-purity quartz synergistic regeneration preparation technology system integrating "multi-dimensional fine polishing - intelligent separation - structural reconstruction - interface purification" was developed. Using the obtained reusable high-purity quartz boats / rods / plates as raw materials, a scheme based on the synergistic effect of physical crushing and reconstruction and surface chemical purification was proposed. Through in-depth analysis of the microstructure and inclusion characteristics of quartz particles, a full-process control system from crystal structure reconstruction to precise removal of interface impurities was established. This achieved adjustable and controllable quartz sand in terms of purity, particle size distribution, morphology, and microstructure, obtaining high-purity quartz sand with a stable purity of over 99.99%, meeting the requirements for high-purity quartz products and raw materials in the semiconductor and photovoltaic industries.

[0011] Specifically, in order to solve the above problems, the present invention provides the following technical solution:

[0012] [1] A method for recycling and reusing used waste quartz boats / quartz rods / quartz plates, comprising the following steps:

[0013] S1: Wash the used waste quartz boats / quartz rods / quartz plates with water and then dry them;

[0014] S2: The dried waste quartz boat / quartz rod / quartz plate is subjected to multi-dimensional mechanical polishing to remove the surface erosion layer, resulting in polished quartz boat / quartz rod / quartz plate; the polished quartz boat is then placed in a mixed acid system of HF:HCl:H2SO4 for treatment, washing, and annealing to obtain regenerated high-purity quartz boat / quartz rod / quartz plate.

[0015] [2] According to the method described in [1], the multidimensional mechanical polishing is carried out in a multi-axis linkage automatic polishing equipment, the equipment including a spindle rotation control system, a radial feed control system, a normal pressure control system, a trajectory control system, a laser displacement sensor and an infrared spectral feedback system.

[0016] [3] According to the method described in [2], wherein the spindle rotation control system controls the precise rotation speed and direction adjustment of the polishing spindle; the radial feed control system controls the radial displacement and feed speed of the polishing nozzle relative to the surface of the waste quartz boat / quartz rod / quartz plate; the normal pressure control system regulates the contact stress between the polishing nozzle and the workpiece surface; the trajectory control system controls the movement path of the polishing nozzle in multi-dimensional space and adjusts the polishing trajectory; the laser displacement sensor and infrared spectral feedback system monitor the degree of removal of the erosion layer in real time;

[0017] Furthermore, when the wavenumber of the Si-O-Si vibration peak on the surface of the quartz boat / quartz rod / quartz plate was detected to be 1080 cm⁻¹ -1 Multidimensional mechanical polishing is completed when the accuracy is ±3%.

[0018] [4] According to any one of [1]-[3], wherein the spindle rotation control system controls the spindle rotation speed to be 800-1200 rpm, and achieves forward and reverse adjustable rotation according to the surface morphology of the waste quartz boat / quartz rod / quartz plate; the radial feed control system controls the feeding speed of the polishing nozzle relative to the surface of the waste quartz boat / quartz rod / quartz plate to be 0.05-1.0 mm / s, and the radial feed amount to be 0.1-100.0 mm; the normal pressure control system adjusts the contact pressure between the nozzle and the surface of the waste quartz boat / quartz rod / quartz plate to be 0.6-1.0 MPa; the trajectory control system controls the polishing nozzle to move along a spiral or reciprocating trajectory in a multidimensional space, the trajectory scanning speed to be 1-50 mm / s, and the trajectory positioning accuracy to be ±(5-20) μm;

[0019] The multidimensional mechanical polishing is carried out in the presence of polishing media, which are silicon carbide sand or quartz sand; further, the particle size of the polishing media is 100-300 μm.

[0020] [5] The method according to any one of [1]-[4], wherein the HF:HCl:H2SO4 mixed acid system is obtained by mixing HF aqueous solution, HCl aqueous solution and H2SO4 aqueous solution, and the volume ratio of HF aqueous solution, HCl aqueous solution and H2SO4 aqueous solution is 1:(1-3):(0.2-1); wherein the concentration of HF aqueous solution is 2-6 mol / L, the concentration of HCl aqueous solution is 3-6 mol / L and the concentration of H2SO4 aqueous solution is 1-5 mol / L;

[0021] The polished quartz boat / quartz rod / quartz plate is placed in a mixed acid system of HF:HCl:H2SO4 at a temperature of 60-100℃.

[0022] The polished quartz boat / quartz rod / quartz plate is placed in a mixed acid system of HF:HCl:H2SO4 for more than 2 hours.

[0023] [6] The method according to any one of [1]-[5], wherein the SiO2 purity of the regenerated high-purity quartz boat / quartz rod / quartz plate obtained in step S2 is above 99.99%.

[0024] [7] The method according to any one of [1]-[6], wherein the method further comprises the following steps:

[0025] S3: The recycled high-purity quartz boat / quartz rod / quartz plate is crushed to obtain quartz sand particles of different sizes; the quartz sand particles are placed in a mixed acid system of HF:HCl:H2SO4 for treatment, washing, grading, and annealing to obtain high-purity quartz sand products of different sizes.

[0026] [8] According to the method described in [7], in step S3, the crushing is carried out in a low-energy shear crusher; further, the crushing energy density is controlled at 0.5-2 kJ / g.

[0027] [9] According to the method described in [7] or [8], the SiO2 purity of the high-purity quartz sand product obtained in step S3 is above 99.99%, and the particle size is in the range of 16-325 mesh.

[0028]

[10] The method according to any one of [1]-[9], wherein, in step S2, polished powder is obtained simultaneously with the polished quartz boat / quartz rod / quartz plate, the method further includes the following steps:

[0029] S4: The polished powder obtained in step S2 is subjected to gas-solid separation and particle size control by a combination of cyclone classification and airflow separation. Powder with a particle size of no more than 60 μm is selected as recyclable surface material, and the recyclable surface material is recycled back to step S2 as polishing medium.

[0030] The effects of the invention

[0031] Compared with existing technologies, this invention provides an innovative process for the graded recycling of waste quartz boats / quartz rods / quartz plates. Specifically, this invention has the following beneficial effects:

[0032] (1) The overall technical path of the present invention realizes the closed-loop regeneration from waste quartz boats / quartz rods / quartz plates to high-purity quartz materials. Compared with traditional processes, it avoids the problem of surface damage to recycled products leading to unusability. The process is shorter, energy consumption is lower, production cost is lower, and there is no waste gas or waste liquid discharge.

[0033] (2) By using multi-stage separation technology to achieve efficient separation of materials, it is possible to obtain 4N grade high-purity quartz boats / quartz rods / quartz plates and high-purity quartz sand products with complete structures. At the same time, the impurity content in the obtained high-purity quartz boats / quartz rods / quartz plates and high-purity quartz sand products is low, the surface roughness of quartz boats / quartz rods / quartz plates is low, the morphology of quartz sand particles is uniform, and the surface finish is excellent.

[0034] The method of this invention has significant advantages in terms of recycling efficiency, energy consumption control and environmental friendliness of waste quartz boats / quartz rods / quartz plates. It can realize the resource utilization of waste quartz boats / quartz rods / quartz plates into high-value materials and has broad application prospects. Detailed Implementation

[0035] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0036] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0037] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0038] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0039] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0040] In this specification, the range of values ​​referred to as “value A - value B” is the range that includes the endpoint values ​​A and B.

[0041] In this specification, the range of values ​​referred to as "above value A" or "below value A" refers to the range including the endpoint value A.

[0042] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-30℃, or further 15-25℃, such as 20℃, 25℃, etc.

[0043] In this manual, "ppm" refers to mass ppm.

[0044] This invention provides a "multi-dimensional fine polishing-intelligent separation" technology, and further provides an integrated high-purity quartz synergistic regeneration preparation technology system encompassing "multi-dimensional fine polishing-intelligent separation-structural reconstruction-interface purification". Based on a systematic study of the surface composition and interface structure of waste quartz boats / quartz rods / quartz plates, a synergistic regeneration system integrating multi-dimensional mechanical fine polishing, directional peeling, and intelligent separation is established. Through precise control of the interaction between the eroded layer and the substrate interface, efficient separation and removal between layers are achieved, avoiding damage to the surface of quartz boats / quartz rods / quartz plates in traditional processes. This allows used quartz boats / quartz rods / quartz plates to be recycled and reused while maintaining structural integrity, yielding reusable high-purity quartz boats / quartz rods / quartz plates.

[0045] Furthermore, using recycled high-purity quartz boats / rods / plates as raw materials, this invention proposes a scheme based on the synergistic effect of physical crushing and reconstruction and surface chemical purification. Through in-depth analysis of the microstructure and inclusion characteristics of quartz particles, a full-process control system from crystal structure reconstruction to precise removal of interface impurities is established. This enables adjustable and controllable quartz sand in terms of purity, particle size distribution, morphology, and microstructure, achieving a stable purity of over 99.99% for high-purity quartz sand, meeting the requirements for high-purity quartz products and raw materials in the semiconductor and photovoltaic industries.

[0046] Multi-dimensional precision polishing and intelligent separation for the synergistic regeneration of used quartz boats

[0047] In a first aspect, this invention utilizes a multi-dimensional fine polishing and intelligent separation synergistic regeneration technology for used waste quartz boats / quartz rods / quartz plates to achieve the recycling of high-purity quartz boats / quartz rods / quartz plates. Specifically, this invention provides a method for recycling and reusing used waste quartz boats / quartz rods / quartz plates, which includes the following steps:

[0048] S1: Wash the used waste quartz boats / quartz rods / quartz plates with water and then dry them;

[0049] S2: The dried waste quartz boat / quartz rod / quartz plate is subjected to multi-dimensional mechanical polishing to remove the surface erosion layer, resulting in polished quartz boat / quartz rod / quartz plate; the polished quartz boat / quartz rod / quartz plate is then placed in a mixed acid system of HF:HCl:H2SO4 for treatment, washing, and annealing to obtain recycled high-purity quartz boat / quartz rod / quartz plate products.

[0050] In some implementations, the multidimensional mechanical polishing is performed in a multi-axis linkage automatic polishing device independently designed by the inventor. This device includes a spindle rotation control system, a radial feed control system, a normal pressure control system, a trajectory control system, a laser displacement sensor, and an infrared spectral feedback system. Specifically, the spindle rotation control system controls the precise rotational speed and direction adjustment of the polishing spindle; the radial feed control system controls the radial displacement and feed speed of the polishing nozzle relative to the surface of the waste quartz boat / quartz rod / quartz plate; the normal pressure control system regulates the contact stress between the polishing nozzle and the workpiece surface; the trajectory control system controls the movement path of the polishing nozzle in multidimensional space and adjusts the polishing trajectory; and the laser displacement sensor and infrared spectral feedback system monitor the degree of erosion layer removal in real time.

[0051] In this invention, in the multi-axis linkage automatic polishing equipment, the main shaft rotation control system is used to achieve precise speed and direction adjustment of the polishing main shaft. Through servo drive and real-time feedback control, it ensures the stable speed of the polishing nozzle under different working conditions. Its rotation speed can be continuously adjusted within the range of 800-1200 rpm to adapt to the differences in the thickness and hardness of the eroded layer on the surface of the waste quartz boat after use, so as to achieve high-precision uniform polishing without producing local structural deformation.

[0052] In some implementations, the spindle rotation control system controls the spindle speed to be 800-1200 rpm, such as 900 rpm, 1000 rpm, 1100 rpm, etc., and can achieve forward and reverse adjustable rotation according to the surface morphology of waste quartz boats / quartz rods / quartz plates.

[0053] In this invention, within the multi-axis linkage automatic polishing equipment, the radial feed control system controls the radial displacement and feed speed of the polishing nozzle relative to the workpiece surface, ensuring dynamic adjustability of polishing depth and accuracy. A micron-level feed step is achieved through a CNC servo drive device. Combined with real-time surface feedback signals, the feed rate is automatically adjusted to adapt to differences in the erosion layer thickness and angle at different locations on the quartz boat / quartz rod / quartz plate. This ensures removal efficiency while avoiding excessive cutting or matrix damage, guaranteeing the structural integrity and dimensional accuracy of the regenerated quartz boat / quartz rod / quartz plate.

[0054] In some embodiments, the radial feed control system controls the grinding nozzle to feed at a speed of 0.05-1.0 mm / s relative to the surface of the waste quartz boat / quartz rod / quartz slab, such as 0.1 mm / s, 0.2 mm / s, 0.5 mm / s, 0.8 mm / s, etc.; and the radial feed amount is 0.1-100.0 mm, such as 0.5 mm, 1 mm, 5 mm, 10 mm, 20 mm, 50 mm, 80 mm, etc.

[0055] In this invention, in the multi-axis linkage automatic polishing equipment, the normal pressure control system uses a pneumatic servo and force feedback sensing module to precisely control the contact stress between the polishing nozzle and the workpiece surface, thereby achieving constant force polishing, effectively improving the consistency of surface removal, reducing microcracks and thermal damage, and significantly improving the surface flatness and mirror quality of recycled quartz materials.

[0056] In some implementations, the normal pressure control system adjusts the contact pressure between the nozzle and the surface of the waste quartz boat / quartz rod / quartz plate to 0.6-1.0 MPa, such as 0.7 MPa, 0.8 MPa, 0.9 MPa, etc.

[0057] In this invention, the trajectory control system in the multi-axis linkage automatic polishing equipment is used to plan the composite motion path of the grinding head in multi-dimensional space, ensuring that the polishing trajectory covers the complex inner and outer curved surfaces and end faces of the quartz boat, achieving a comprehensive and uniform removal effect. Based on a multi-axis linkage CNC platform, combined with a preset three-dimensional model and surface morphology detection data, an optimal polishing trajectory is generated. The trajectory control system coordinates the collaborative work of the three subsystems: spindle rotation, radial feed, and normal pressure, thereby avoiding repetitive processing and local over-polishing, and achieving high-precision control of the surface roughness of the quartz boat.

[0058] In some implementations, the trajectory control system controls the polishing nozzle to move along a spiral or reciprocating trajectory in a multidimensional space. The trajectory scanning speed is 1-50 mm / s, such as 2 mm / s, 5 mm / s, 10 mm / s, 20 mm / s, 30 mm / s, etc.; the trajectory positioning accuracy is ±(5-20) μm, such as ±5 μm, ±8 μm, ±10 μm, ±15 μm, etc.

[0059] In this invention, in the multi-axis linkage automatic polishing equipment, the laser displacement sensor and the infrared spectral feedback system function to monitor the degree of erosion layer removal in real time; furthermore, when the Si-O-Si vibration peak wavenumber on the surface of the quartz boat / quartz rod / quartz plate is detected to be 1080 cm⁻¹, -1 When the percentage is ±3%, it indicates that the surface erosion layer has been completely removed and the multi-dimensional mechanical polishing is complete.

[0060] In some embodiments, the multidimensional mechanical polishing is carried out in the presence of polishing media, which are silicon carbide sand or quartz sand; further, the particle size of the polishing media is 100-300 μm, such as 150 μm, 200 μm, 250 μm, etc.

[0061] In some embodiments, the HF:HCl:H2SO4 mixed acid system is obtained by mixing an aqueous HF solution, an aqueous HCl solution, and an aqueous H2SO4 solution, wherein the volume ratio of the aqueous HF solution, the aqueous HCl solution, and the aqueous H2SO4 solution is 1:(1-3):(0.2-1), preferably 1:(1.5-2.5):(0.4-0.6), for example 1:2:0.5; wherein the concentration of the aqueous HF solution is 2-6 mol / L, the concentration of the aqueous HCl solution is 3-6 mol / L, and the concentration of the aqueous H2SO4 solution is 1-5 mol / L.

[0062] In some implementations, the polished quartz boat / quartz rod / quartz plate is placed in a mixed acid system of HF:HCl:H2SO4 at a temperature of 60-100℃, such as 70℃, 80℃, 90℃, etc., for a time of more than 2 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, 8 hours, 10 hours, etc., such as 2-6 hours.

[0063] In some implementations, the washing is performed with water until the pH reaches 7, thus completely removing the acid from the surface of the quartz sand particles.

[0064] In this invention, the annealing step can eliminate residual thermal stress and promote microcrack healing and lattice rearrangement. In some embodiments, in step S2, the annealing temperature is 600-1200℃, such as 700℃, 800℃, 900℃, 1000℃, 1100℃, etc., and the annealing time is 2-5 h, such as 3 h, 4 h, 5 h, etc.

[0065] In some implementations, the SiO2 purity of the recycled high-purity quartz boat / quartz rod / quartz plate product obtained in step S2 is above 99.99%, such as 99.991%, 99.992%, 99.993%, 99.994%, 99.995%, etc.

[0066] In some implementations, the surface roughness Ra of the recycled high-purity quartz boat / quartz rod / quartz plate product obtained in step S2 is ≤0.2 μm or ≤0.15 μm.

[0067] In some implementations, the Al2O3 content of the recycled high-purity quartz boat / quartz rod / quartz plate product obtained in step S2 is no more than 1 ppm or no more than 0.9 ppm.

[0068] In some implementations, the Fe2O3 (T) content of the recycled high-purity quartz boat / quartz rod / quartz plate product obtained in step S2 is no more than 0.5 ppm or no more than 0.3 ppm.

[0069] In some implementations, the TiO2 content of the recycled high-purity quartz boat / quartz rod / quartz plate product obtained in step S2 is no more than 0.08 ppm or no more than 0.05 ppm.

[0070] Physical structure reconstruction and surface purification

[0071] The "multi-dimensional fine polishing and intelligent separation synergistic regeneration technology" mentioned in the first aspect above yields recycled high-purity quartz boats / quartz rods / quartz slabs. Using these as raw materials, high-purity quartz sand can also be obtained through "physical structure reconstruction and surface / interface purification technology." Specifically, the method for recycling and reusing used waste quartz boats / quartz rods / quartz slabs according to this invention further includes the following steps:

[0072] S3: The recycled high-purity quartz boat / quartz rod / quartz plate is crushed to obtain quartz sand particles of different sizes; the quartz sand particles are placed in a mixed acid system of HF:HCl:H2SO4 for treatment, washing, classification, and annealing to obtain high-purity quartz sand products of different particle sizes.

[0073] In some implementations, step S3 involves crushing in a low-energy shear crusher. Low-energy shear crushing reduces impurity generation and improves the purity of the quartz sand product. Unlike traditional high-energy impact crushing or ball milling, low-energy shear crushing primarily utilizes the combined effect of shear stress and slight compressive stress to cause dissociation and interfacial peeling of recycled quartz boats / bars / plates along the anisotropic direction of the crystal structure. This process occurs under low strain rate conditions, avoiding localized overheating and mechanical stress concentration, thereby reducing lattice damage and the formation of new surface active sites. It also prevents impurities such as Fe, Al, and Ti from migrating into the quartz particle surface due to mechanical friction during crushing. Furthermore, the working internal layer and contact components of the low-energy shear crusher use high-purity alumina or polytetrafluoroethylene (PTFE) anti-fouling linings to further suppress secondary contamination by metal ions. Precise control of crushing speed, shear angle, and particle residence time ensures that the resulting quartz sand has a particle size range of 16-200 mesh, with smooth, crack-free particle surfaces.

[0074] In some implementations, during step S3, the crushing speed is controlled to be 200–800 rpm, such as 300 rpm, 400 rpm, 500 rpm, 600 rpm, etc.

[0075] In some implementations, during step S3, the shearing angle is controlled to be 15-45°, such as 20°, 25°, 30°, 40°, etc.

[0076] In some implementations, during step S3, the particle residence time is controlled to be 3-20 min, such as 5 min, 8 min, 10 min, 15 min, 18 min, etc.

[0077] In some implementations, during step S3, the crushing energy density is controlled to be between 0.5 and 2 kJ / g, for example, 0.8 kJ / g, 1 kJ / g, 1.2 kJ / g, 1.5 kJ / g, 1.8 kJ / g, etc.

[0078] In some embodiments, the HF:HCl:H2SO4 mixed acid system is obtained by mixing an aqueous HF solution, an aqueous HCl solution, and an aqueous H2SO4 solution, wherein the volume ratio of the aqueous HF solution, the aqueous HCl solution, and the aqueous H2SO4 solution is 1:(2-4):(0.5-2), preferably 1:(2.5-3.5):(0.8-1.5), for example 1:3:1; wherein the concentration of the aqueous HF solution is 2-6 mol / L, the concentration of the aqueous HCl solution is 3-6 mol / L, and the concentration of the aqueous H2SO4 solution is 1-5 mol / L.

[0079] In some implementations, the quartz sand particles are placed in a mixed acid system of HF:HCl:H2SO4 at a temperature of 60-100℃, such as 70℃, 80℃, 90℃, etc., and the time is controlled to be more than 2 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, 8 hours, 10 hours, etc., such as 2-6 hours.

[0080] In some implementations, the washing is performed with water until the pH reaches 7, thus completely removing the acid from the surface of the quartz sand particles.

[0081] In this invention, the annealing step can eliminate residual thermal stress and promote microcrack healing and lattice rearrangement. In some embodiments, the annealing temperature is 800-1200℃, such as 700℃, 800℃, 900℃, 1000℃, 1100℃, etc., and the annealing time is 2-5 h, such as 3 h, 4 h, 5 h, etc.

[0082] In some implementations, the SiO2 purity of the high-purity quartz sand product obtained in step S3 is above 99.99%, such as 99.991%, 99.992%, 99.993%, 99.994%, 99.995%, etc.

[0083] In some implementations, the particle size of the high-purity quartz sand product obtained in step S3 is in the range of 16-325 mesh, preferably in the range of 16-200 mesh.

[0084] In some implementations, the Al2O3 content of the high-purity quartz sand product obtained in step S3 is no more than 1 ppm or no more than 0.8 ppm.

[0085] In some implementations, the Fe2O3 (T) content of the high-purity quartz sand product obtained in step S3 is no more than 0.5 ppm or no more than 0.3 ppm.

[0086] In some implementations, the TiO2 content of the high-purity quartz sand product obtained in step S3 is no more than 0.08 ppm or no more than 0.05 ppm.

[0087] In some embodiments, in step S2, polished powder is obtained simultaneously with the polished quartz boat. The method for recycling and reusing used waste quartz boats according to the present invention further includes the following steps:

[0088] S4: The polished powder obtained in step S2 is subjected to gas-solid separation and particle size control by a combination of cyclone classification and airflow separation; further, powder with a particle size of no more than 60 μm (e.g., 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, etc.) can be selected as recyclable surface material, and the recyclable surface material is recycled back to step S2 as polishing medium.

[0089] Example

[0090] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0091] The HF used in the examples is a 3 mol / L aqueous solution of HF, the HCl used in the examples is a 5 mol / L aqueous solution of HCl, and the H2SO4 used in the examples is a 3 mol / L aqueous solution of H2SO4.

[0092] The multi-axis linkage automatic polishing equipment used in the embodiment was designed by the inventor. The equipment includes a spindle rotation control system, a radial feed control system, a normal pressure control system, a trajectory control system, a laser displacement sensor, and an infrared spectral feedback system.

[0093] Example 1

[0094] (1) Collect quartz rods that have been scrapped after being used by semiconductor companies. Clean the dust and residues on their outer surface with deionized water using ultrasonic cleaning and then dry them for later use. Use X-ray fluorescence spectrometer and scanning electron microscope-energy dispersive spectroscopy to determine that the main components of the etched layer are Si, Sn, In, etc., and the thickness is 0.35 mm.

[0095] (2) Multidimensional fine polishing and intelligent separation synergistic regeneration: The dried waste quartz rods are placed in a multi-axis linkage automatic polishing equipment. The spindle rotation control system, radial feed control system, normal pressure control system, trajectory control system, laser displacement sensor and infrared spectral feedback system are turned on. Quartz sand with a particle size of 200 μm is used as the polishing medium. Multidimensional mechanical fine polishing is carried out under the conditions of pressure control of 0.8 MPa, polishing speed of 1000 rpm, feed speed of 0.3 mm / s and radial feed of 5 mm. The degree of erosion layer removal is monitored in real time by laser displacement sensor and infrared spectral feedback system. The polishing trajectory is adjusted by trajectory control system. The trajectory scanning speed is 50 mm / s and the trajectory positioning accuracy is ±10 μm. When the Si-O-Si vibration peak wavenumber on the surface of the quartz rod is detected to recover to the characteristic value of high-purity quartz (1080 cm⁻¹), the polishing process is completed. -1 When the surface erosion layer is determined to be completely removed at a concentration of ±3%, the multi-dimensional fine polishing process is considered complete. The material is then further placed in a mixed acid system (HF:HCl:H2SO4 = 1:2:0.5, volume ratio), treated at 80℃ for 4 h, washed with water, dried at 80℃, and annealed at 800℃ for 3 h to obtain recycled high-purity quartz rods with a surface roughness Ra ≤ 0.12 μm. Inductively coupled plasma mass spectrometry analysis showed that the SiO2 purity in the recycled high-purity quartz rods was 99.993%, and the impurity contents were Al2O3 0.82 ppm, Fe2O3 (T) 0.30 ppm, and TiO2 0.05 ppm.

[0096] (3) Physical structure reconstruction and surface purification: The obtained regenerated high-purity quartz rods were fed into a low-energy shear crusher for crushing. The crushing energy density was controlled at 1 kJ / g, the crushing speed was controlled at 500 rpm, the shear angle was controlled at 30°, and the particle retention time was controlled at 10 min to obtain quartz sand particles with a particle size of 16-200 mesh. Surface purification was further carried out in a dynamic mixed acid system (HF:HCl:H2SO4=1:3:1, volume ratio). The acid flow rate was controlled at 0.5-1.0 L / min, the reaction temperature was 80℃, and the time was 2 h. The particles were dynamically rinsed with ultrapure water until pH=7, dried at 80℃ for 6 h, and then annealed at 1000℃ for 3 h to eliminate residual thermal stress, promote microcrack healing and lattice rearrangement, and finally obtain high-purity quartz sand products. Analysis by plasma mass spectrometry showed that the high-purity quartz sand product contained 99.991% SiO2, 0.79 ppm Al2O3, 0.28 ppm Fe2O3 (T), and 0.045 ppm TiO2. The particles had uniform morphology and excellent surface finish, meeting the standards for high-purity quartz sand used in semiconductors.

[0097] (4) Intelligent separation and collection of surface powder: The powder generated during the polishing process is separated and collected by a negative pressure suction system. Gas-solid separation and particle size control are carried out by a combination of cyclone classification and airflow separation. Powder with a particle size of 1-60 μm is selected as the subsequent recyclable surface material and used as the polishing medium.

[0098] Example 2

[0099] (1) Collect quartz boats that have been scrapped after being used by semiconductor companies. Clean the dust and residues on their outer surface with deionized water using ultrasonic cleaning and then dry them for later use. Use X-ray fluorescence spectrometer and scanning electron microscope-energy dispersive spectroscopy to determine that the main components of the etched layer are Si, Sn, In, etc., and the thickness is 0.50 mm.

[0100] (2) Multidimensional fine polishing and intelligent separation synergistic regeneration: The dried waste quartz slabs are placed into a multi-axis linkage automatic polishing equipment. The spindle rotation control system, radial feed control system, normal pressure control system, trajectory control system, laser displacement sensor and infrared spectral feedback system are turned on. Quartz sand with a particle size of 200 μm is used as the polishing medium. Multidimensional mechanical fine polishing is carried out under the conditions of pressure control of 0.8 MPa, polishing speed of 1100 rpm, feed speed of 0.4 mm / s and radial feed of 5 mm. The degree of removal of the eroded layer is monitored in real time by the laser displacement sensor and infrared spectral feedback system. The polishing trajectory is adjusted by the trajectory control system. The trajectory scanning speed is 5 mm / s and the trajectory positioning accuracy is ±10 μm. When the wavenumber of the Si-O-Si vibration peak on the surface of the quartz boat is detected to recover to the characteristic value of high-purity quartz (1080 cm⁻¹), the polishing process is completed.-1 When the surface erosion layer is determined to be completely removed at a concentration of ±3%, the multi-dimensional fine polishing process is considered complete. The material is then further placed in a mixed acid solution system (HF:HCl:H2SO4 = 1:2:0.5, volume ratio), treated at 80℃ for 5 h, washed with water, dried at 80℃, and annealed at 800℃ for 3 h to obtain a regenerated high-purity quartz boat with a surface roughness Ra ≤ 0.12 μm. Inductively coupled plasma mass spectrometry analysis showed that the SiO2 purity in the regenerated high-purity quartz boat was 99.991%, and the impurity contents were Al2O3 0.78 ppm, Fe2O3 (T) 0.29 ppm, and TiO2 0.06 ppm.

[0101] (3) Physical structure reconstruction and surface purification: The obtained regenerated high-purity quartz boat was fed into a low-energy shear crusher for crushing. The crushing energy density was controlled at 1 kJ / g, the crushing speed was controlled at 500 rpm, the shear angle was controlled at 25°, and the particle retention time was controlled at 8 min to obtain quartz sand particles with a particle size of 16-200 mesh. Surface purification was further carried out in a dynamic mixed acid system (HF:HCl:H2SO4=1:3:1, volume ratio). The acid flow rate was controlled at 0.5-1.0 L / min, the reaction temperature was 80℃, and the time was 2 h. The surface was dynamically rinsed with ultrapure water until pH=7, dried at 80℃ for 6 h, and then annealed at 1000℃ for 3 h to finally obtain high-purity quartz sand product. Analysis by plasma mass spectrometry showed that the high-purity quartz sand product contained 99.990% SiO2, 0.77 ppm Al2O3, 0.28 ppm Fe2O3 (T), and 0.049 ppm TiO2. The particles had uniform morphology and excellent surface smoothness.

[0102] (4) Intelligent separation and collection of surface powder: The powder generated during the polishing process is separated and collected by a negative pressure suction system. Gas-solid separation and particle size control are carried out by a combination of cyclone classification and airflow separation. Powder with a particle size of 1-60 μm is selected as the subsequent recyclable surface material and used as the polishing medium.

[0103] Example 3

[0104] (1) Collect the quartz plates that have been scrapped after being used by semiconductor companies. Clean the dust and residues on the outer surface of the plates with deionized water using ultrasonic cleaning and then dry them for later use. The main components of the etched layer are determined to be Si, Sn, In, etc., and the thickness is 0.57 mm.

[0105] (2) Multidimensional fine polishing and intelligent separation synergistic regeneration: The dried waste quartz slabs are placed in a multi-axis linkage automatic polishing equipment. The spindle rotation control system, radial feed control system, normal pressure control system, trajectory control system, laser displacement sensor and infrared spectral feedback system are turned on. Silicon carbide with a particle size of 200 μm is used as the polishing medium. Multidimensional mechanical fine polishing is performed under the conditions of pressure control of 0.9 MPa, polishing speed of 1100 rpm, feed speed of 0.5 mm / s and radial feed of 5 mm. The degree of removal of the eroded layer is monitored in real time by the laser displacement sensor and infrared spectral feedback system. The polishing trajectory is adjusted by the trajectory control system. The trajectory scanning speed is 5 mm / s and the trajectory positioning accuracy is ±10 μm. When the wavenumber of the Si-O-Si vibration peak on the surface of the quartz slab is detected to recover to the characteristic value of high-purity quartz (1080 cm⁻¹), the polishing process is completed. -1 When the surface erosion layer is determined to be completely removed (±3%), the multi-dimensional fine polishing process is considered complete. The material is then further placed in a mixed acid system (HF:HCl:H2SO4 = 1:2:0.5, volume ratio), treated at 80℃ for 5 h, washed with water, dried at 80℃, and annealed at 800℃ for 3 h to obtain a recycled high-purity quartz slab with a surface roughness Ra≤0.12 μm. Inductively coupled plasma mass spectrometry analysis showed that the SiO2 purity in the recycled high-purity quartz slab was 99.992%, and the impurity contents were Al2O3 0.74 ppm, Fe2O3 (T) 0.28 ppm, and TiO2 0.05 ppm.

[0106] (3) Physical structure reconstruction and surface purification: The obtained regenerated high-purity quartz plates were fed into a low-energy shear crusher for crushing. The crushing energy density was controlled at 1.1 kJ / g, the crushing speed was controlled at 600 rpm, the shear angle was controlled at 30°, and the particle retention time was controlled at 5 min to obtain quartz sand particles with a particle size of 16-200 mesh. Surface purification was further carried out in a dynamic mixed acid system (HF:HCl:H2SO4=1:3:1, volume ratio). The acid flow rate was controlled at 0.5-1.0 L / min, the reaction temperature was 80℃, and the time was 2 h. The particles were dynamically rinsed with ultrapure water until pH=7, dried at 100℃ for 6 h, and then annealed at 1000℃ for 3 h to finally obtain high-purity quartz sand products. Analysis by plasma mass spectrometry showed that the high-purity quartz sand product contained 99.991% SiO2, 0.75 ppm Al2O3, 0.26 ppm Fe2O3 (T), and 0.048 ppm TiO2. The particles had uniform morphology and excellent surface smoothness.

[0107] (4) Intelligent separation and collection of surface powder: The powder generated during the polishing process is separated and collected by a negative pressure suction system. Gas-solid separation and particle size control are carried out by a combination of cyclone classification and airflow separation. Powder with a particle size of 1-60 μm is selected as the subsequent recyclable surface material and used as the polishing medium.

[0108] Comparative Example 1

[0109] (1) Collect quartz boats that have been scrapped after being used by semiconductor companies. Clean the dust and residues on their outer surface with deionized water using ultrasonic cleaning and then dry them for later use. Use X-ray fluorescence spectrometer and scanning electron microscope-energy dispersive spectroscopy to determine that the main components of the etched layer are Si, Sn, In, etc., and the thickness is 0.46 mm.

[0110] (2) The cleaned and dried waste quartz boat is placed into a sandblasting and polishing equipment, using quartz sand with a particle size of 1 mm as the polishing medium, and the blasting pressure is controlled at 0.8 MPa and 0.5 m. 3 Polishing was performed at a speed of [value] / min for 3 h to completely remove the surface erosion layer. The material was then further placed in a mixed acid solution system (HF:HCl:H2SO4 = 1:2:0.5) and treated at 80℃ for 5 h. After washing with water and drying at 80℃, it was annealed at 800℃ for 3 h to obtain a regenerated quartz boat with a surface roughness Ra ≤ 0.8 μm. Inductively coupled plasma mass spectrometry analysis showed that the SiO2 purity in the regenerated quartz boat was 99.91%, and the impurity contents were Al2O3 22 ppm, Fe2O3 (T) 60 ppm, and TiO2 1.8 ppm.

[0111] Comparative Example 2

[0112] (1) Collect quartz boats that have been scrapped after being used by semiconductor companies. Clean the dust and residues on their outer surface with deionized water using ultrasonic cleaning and then dry them for later use. Use X-ray fluorescence spectrometer and scanning electron microscope-energy dispersive spectroscopy to determine that the main components of the etched layer are Si, Sn, In, etc., and the thickness is 0.57 mm.

[0113] (2) The dried waste quartz boat was placed into a multi-axis linkage automatic polishing equipment. The spindle rotation control system, radial feed control system, normal pressure control system, trajectory control system, laser displacement sensor and infrared spectral feedback system were turned on. Silicon carbide with a particle size of 200 μm was used as the polishing medium. Multidimensional mechanical fine polishing was performed under the conditions of pressure control of 0.9 MPa, polishing speed of 1100 rpm, feed speed of 0.3 mm / s and radial feed of 5 mm. The degree of removal of the eroded layer was monitored in real time by the laser displacement sensor and infrared spectral feedback system. The polishing trajectory was adjusted by the trajectory control system. The trajectory scanning speed was 5 mm / s and the trajectory positioning accuracy was ±10 μm. When the wavenumber of the Si-O-Si vibration peak on the surface of the quartz plate was detected to recover to the characteristic value of high-purity quartz (1080 cm⁻¹), the polishing was completed. -1 When the surface erosion layer is determined to be completely removed at a concentration of ±3%, the multi-dimensional fine polishing process is considered complete. The material is then further placed in a mixed acid solution system (HF:HCl:H2SO4 = 1:2:0.5, volume ratio), treated at 80℃ for 5 h, washed with water, dried at 80℃, and annealed at 800℃ for 3 h to obtain a regenerated high-purity quartz boat with a surface roughness Ra ≤ 0.12 μm. Inductively coupled plasma mass spectrometry analysis showed that the SiO2 purity in the regenerated high-purity quartz boat was 99.992%, and the impurity contents were Al2O3 0.74 ppm, Fe2O3 (T) 0.28 ppm, and TiO2 0.05 ppm.

[0114] (3) The obtained regenerated high-purity quartz boat was fed into a high-energy impact mill for crushing. The rotor speed was controlled at 3500 rpm and the grading screen was 1 mm to obtain quartz sand particles with a particle size of less than 200 mesh. Surface purification was further carried out in a dynamic mixed acid system (HF:HCl:H2SO4=1:3:1, volume ratio). The acid flow rate was controlled at 0.5-1.0 L / min, the reaction temperature at 80℃, and the time at 2 h. After dynamic rinsing with ultrapure water to pH=7, the product was dried at 100℃ for 6 h and then annealed at 1000℃ for 3 h to finally obtain the quartz sand product. Analysis by plasma mass spectrometry showed that the quartz sand product contained 99.88% SiO2, 52 ppm Al2O3, 496 ppm Fe2O3 (T), and 78 ppm TiO2.

[0115] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0116] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for recycling and reusing used waste quartz boats / quartz rods / quartz plates, comprising the following steps: S1: Wash the used waste quartz boats / quartz rods / quartz plates with water and then dry them; S2: The dried waste quartz boat / quartz rod / quartz plate is subjected to multi-dimensional mechanical polishing to remove the surface erosion layer, resulting in polished quartz boat / quartz rod / quartz plate; the polished quartz boat / quartz rod / quartz plate is then placed in a mixed acid system of HF:HCl:H2SO4 for treatment, washing, and annealing to obtain regenerated high-purity quartz boat / quartz rod / quartz plate.

2. The method according to claim 1, characterized in that, The multidimensional mechanical polishing is carried out in a multi-axis linkage automatic polishing equipment, which includes a spindle rotation control system, a radial feed control system, a normal pressure control system, a trajectory control system, a laser displacement sensor, and an infrared spectral feedback system.

3. The method according to claim 2, characterized in that, The spindle rotation control system precisely controls the rotational speed and direction of the polishing spindle; the radial feed control system controls the radial displacement and feed speed of the polishing nozzle relative to the surface of the waste quartz boat / quartz rod / quartz plate; the normal pressure control system regulates the contact stress between the polishing nozzle and the workpiece surface; the trajectory control system controls the movement path of the polishing nozzle in multi-dimensional space and adjusts the polishing trajectory; the laser displacement sensor and infrared spectral feedback system monitor the degree of erosion layer removal in real time. Furthermore, when the wavenumber of the Si-O-Si vibration peak on the surface of the quartz boat / quartz rod / quartz plate was detected to be 1080 cm⁻¹ -1 Multidimensional mechanical polishing is completed when the accuracy is ±3%.

4. The method according to claim 2 or 3, characterized in that, The spindle rotation control system controls the spindle speed to be 800-1200 rpm, and achieves forward and reverse adjustable rotation according to the surface morphology of the waste quartz boat / quartz rod / quartz plate; the radial feed control system controls the feed speed of the polishing nozzle relative to the surface of the waste quartz boat / quartz rod / quartz plate to be 0.05-1.0 mm / s, and the radial feed amount to be 0.1-100.0 mm; the normal pressure control system adjusts the contact pressure between the nozzle and the surface of the waste quartz boat / quartz rod / quartz plate to be 0.6-1.0 MPa; the trajectory control system controls the polishing nozzle to move along a spiral or reciprocating trajectory in multi-dimensional space, with a trajectory scanning speed of 1-50 mm / s and a trajectory positioning accuracy of ±(5-20) μm; The multidimensional mechanical polishing is carried out in the presence of polishing media, which are silicon carbide sand or quartz sand; further, the particle size of the polishing media is 100-300 μm.

5. The method according to any one of claims 1-4, characterized in that, The HF:HCl:H2SO4 mixed acid system is obtained by mixing HF aqueous solution, HCl aqueous solution and H2SO4 aqueous solution, with a volume ratio of HF aqueous solution, HCl aqueous solution and H2SO4 aqueous solution of 1:(1-3):(0.2-1); wherein, the concentration of HF aqueous solution is 2-6 mol / L, the concentration of HCl aqueous solution is 3-6 mol / L and the concentration of H2SO4 aqueous solution is 1-5 mol / L; The polished quartz boat / quartz rod / quartz plate is placed in a mixed acid system of HF:HCl:H2SO4 at a temperature of 60-100℃. The polished quartz boat / quartz rod / quartz plate is placed in a mixed acid system of HF:HCl:H2SO4 for more than 2 hours.

6. The method according to any one of claims 1-5, characterized in that, The SiO2 purity of the recycled high-purity quartz boat / quartz rod / quartz plate obtained in step S2 is above 99.99%.

7. The method according to any one of claims 1-6, characterized in that, The method further includes the following steps: S3: The recycled high-purity quartz boat / quartz rod / quartz plate is crushed to obtain quartz sand particles of different sizes; the quartz sand particles are placed in a mixed acid system of HF:HCl:H2SO4 for treatment, washing, grading, and annealing to obtain high-purity quartz sand products of different sizes.

8. The method according to claim 7, characterized in that, In step S3, the crushing is carried out in a low-energy shear crusher; further, the crushing energy density is controlled at 0.5-2 kJ / g.

9. The method according to claim 7 or 8, characterized in that, The high-purity quartz sand product obtained in step S3 has a SiO2 purity of over 99.99% and a particle size in the range of 16-325 mesh.

10. The method according to any one of claims 1-9, characterized in that, In step S2, polished powder is obtained simultaneously with the polished quartz boat / quartz rod / quartz plate. The method further includes the following steps: S4: The polished powder obtained in step S2 is subjected to gas-solid separation and particle size control by a combination of cyclone classification and airflow separation. Powder with a particle size of no more than 60 μm is selected as recyclable surface material, and the recyclable surface material is recycled back to step S2 as polishing medium.