阅读说明：本技术 一种大尺寸高纯度石英玻璃的化学沉积工艺 (Chemical deposition process for large-size high-purity quartz glass ) 是由 万沂江 于 2020-05-21 设计创作，主要内容包括：一种大尺寸高纯度石英玻璃的化学沉积工艺,包括如下步骤：(1)准备：在立式沉积炉内放置靶料,然后以有机硅八甲基环四硅氧烷为原料,经过精馏提纯后进入蒸发器；(2)沉积：所述有机硅八甲基环四硅氧烷蒸气在燃烧器火焰中热水解生成二氧化硅颗粒,并在立式沉积炉中内绕自身纵向轴旋转的靶料靶面上不断层叠沉积,得到石英玻璃坯体,所述石英玻璃坯体熔化生产合成大尺寸高纯度石英玻璃。本发明所述的大尺寸高纯度石英玻璃的化学沉积工艺,方法简单高效,解决了现有技术中石英玻璃化学沉积工艺羟基含量高的缺点,制得的石英玻璃坯体密度均匀性好,结构透气,有利于后续脱除材料中的羟基,从而获得大尺寸、高纯度的石英玻璃,应用前景广泛。(A chemical deposition process of large-size high-purity quartz glass comprises the following steps: (1) preparing: placing a target material in a vertical deposition furnace, then taking organosilicon octamethylcyclotetrasiloxane as a raw material, and entering an evaporator after rectification and purification; (2) deposition: the organosilicon octamethylcyclotetrasiloxane steam is thermally hydrolyzed in a burner flame to generate silicon dioxide particles, and the silicon dioxide particles are continuously laminated and deposited on a target material target surface rotating around a self longitudinal axis in a vertical deposition furnace to obtain a quartz glass blank, and the quartz glass blank is melted to synthesize large-size high-purity quartz glass. The chemical deposition process of the large-size high-purity quartz glass, disclosed by the invention, is simple and efficient, overcomes the defect of high hydroxyl content in the chemical deposition process of the quartz glass in the prior art, and the prepared quartz glass blank has good density uniformity and a breathable structure, is beneficial to removing hydroxyl in materials subsequently, so that the large-size high-purity quartz glass is obtained, and has a wide application prospect.)

1. A chemical deposition process for large-size high-purity quartz glass is characterized by comprising the following steps:

(1) preparing: placing a target material in a vertical deposition furnace (1), then taking organosilicon octamethylcyclotetrasiloxane as a raw material, rectifying and purifying the raw material, and then feeding the raw material into an evaporator (2) for gasification; the vertical deposition furnace (1) comprises a furnace body (11), a mechanical lifting rotating device (12) for supporting target materials at the lower part in the furnace body (11), and a burner (13) at a furnace mouth (111) above the furnace body (11), wherein the burner (13) is arranged at the furnace mouth (111) through a moving device (14), and the moving device (14) drives the burner (13) to do reciprocating movement in the radial direction of a target material target surface; the mechanical lifting and rotating device (12) drives a target material to lift and rotate around a longitudinal axis of the mechanical lifting and rotating device, and the rotating speed of the target material is 20 r/min; a gap (1111) with the thickness of 20mm is reserved between the burner (13) and the furnace mouth (111);

(2) deposition: the steam of the organosilicon octamethylcyclotetrasiloxane gasified by the evaporator (2) is taken out by the purified nitrogen and is led into the flame of the burner (13) of the vertical deposition furnace (1), the organosilicon octamethylcyclotetrasiloxane steam is thermally hydrolyzed in the flame of the burner (13) to generate silicon dioxide particles, and the silicon dioxide particles are continuously laminated and deposited on the target surface of the target material rotating around the self longitudinal axis in the vertical deposition furnace (1) to obtain a quartz glass blank, and the quartz glass blank is melted to synthesize large-size high-purity quartz glass.

2. The chemical deposition process of large-size high-purity quartz glass according to claim 1, characterized in that the outer wall of the furnace body (11) is a heat-insulating wall (112), the inner wall of the furnace body (11) is a refractory wall (113), and the intermediate layer of the furnace body (11) is an electric heating device (114) and a circulating water cooling device (115).

3. The chemical deposition process of large-size high-purity quartz glass according to claim 2, wherein the thermal insulation wall (112) is composed of refractory asbestos, refractory fiber board, refractory castable or refractory hollow sphere; the refractory wall (113) is composed of alumina, zirconia, silicon carbide or silicon nitride.

4. The chemical deposition process of large-size high-purity quartz glass according to claim 2, wherein a plurality of exhaust vents (116) are provided in the middle of the furnace body (11).

5. The chemical deposition process for large-size high-purity quartz glass according to claim 1, wherein a central loop (131), a first oxygen loop (132), a first hydrogen loop (133), a second oxygen loop (134), a second hydrogen loop (135), and a third oxygen loop (136) are arranged on the top of the burner (13); the central loop (131) is arranged at the center of the top of the burner (13), and the first oxygen loop (132), the first hydrogen loop (133), the second oxygen loop (134), the second hydrogen loop (135) and the third oxygen loop (136) are arranged around the central loop (131) from inside to outside.

6. The chemical deposition process for large-size high-purity quartz glass according to claim 5, wherein the first oxygen gas loop (132) consists of one large oxygen gas loop (1321), the large oxygen gas loop (1321) being arranged around the central loop (131); the oxygen loop II (134) and the oxygen loop III (136) are respectively composed of a plurality of small oxygen loops (1341), and the small oxygen loops (1341) are arranged at equal angles; the hydrogen loop I (133) and the hydrogen loop II (135) are respectively composed of a plurality of small hydrogen loops (1331), and the small hydrogen loops (1331) are arranged at equal angles.

7. The chemical deposition process for large-size high-purity quartz glass according to claim 6, wherein the central loop (131) is connected to an oxygen line and an evaporator line, the first oxygen loop (132) and the plurality of small oxygen loops (1341) are respectively connected to an oxygen line, and the small hydrogen loops (1331) are respectively connected to a hydrogen line.

8. The chemical deposition process for large-size high-purity quartz glass according to claim 7, wherein the oxygen line, the vaporizer line, and the hydrogen line are provided with an automatic constant pressure processor (137) and a mass flow controller (138).

Technical Field

The invention belongs to the technical field of quartz glass preparation, and particularly relates to a chemical deposition process of large-size high-purity quartz glass.

Background

The quartz glass is prepared by high-temperature melting of high-purity quartz or artificially synthesized raw materials extracted from pure natural crystals, silica and quartz-rich rocks, is widely applied in modern technology, provides various key materials for important fields such as optical fiber communication, electric light sources, manned aerospace and the like, and is widely applied to high-tech fields such as laser, semiconductor industry and the like. The quartz glass is the best material in glass materials, and has the advantages of high compressive strength, low expansion coefficient, strong thermal shock resistance, stable chemical properties and high dielectric field strength, and has the reputation of glass king because the quartz glass is superior to other materials in various special properties.

With the expansion of the application field of quartz glass, the performance requirements of the quartz glass are gradually increased. Therefore, the preparation process of the quartz glass with large size, high purity and special requirement is concerned widely. At present, the main production modes are as follows: electric melting process, synthetic quartz glass manufacturing process and high-frequency plasma flame melting process. The manufacturing process of the synthetic quartz glass comprises a chemical vapor deposition process, a vapor axial deposition process, plasma chemical vapor deposition and the like.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects, the invention aims to provide the chemical deposition process for the large-size high-purity quartz glass, which has simple steps and convenient operation, overcomes the defect of high hydroxyl content in the chemical deposition process for the quartz glass in the prior art, and the prepared quartz glass blank has good density uniformity and air-permeable structure, is beneficial to removing the hydroxyl in the material in the subsequent process of melting and producing the synthetic quartz glass, thereby obtaining the large-size high-purity quartz glass and has wide application prospect.

The purpose of the invention is realized by the following technical scheme:

a chemical deposition process for large-size high-purity quartz glass is characterized by comprising the following steps:

(1) preparing: placing a target material in a vertical deposition furnace, then taking organosilicon octamethylcyclotetrasiloxane as a raw material, and introducing the raw material into an evaporator for gasification after rectification and purification; the vertical deposition furnace comprises a furnace body, a mechanical lifting and rotating device for supporting target materials below the inside of the furnace body, and a burner at a furnace mouth above the furnace body, wherein the burner is arranged at the furnace mouth through a moving device, and the moving device drives the burner to do reciprocating movement in the radial direction of a target material target surface; the mechanical lifting and rotating device drives a target material to lift and rotate around a longitudinal axis of the mechanical lifting and rotating device, and the rotating speed of the target material is 20 r/min; a gap of 20mm is reserved between the burner and the furnace mouth;

(2) deposition: the steam of the organosilicon octamethylcyclotetrasiloxane gasified by the evaporator is taken out by the purified nitrogen and is led into the flame of the burner of the vertical deposition furnace, the organosilicon octamethylcyclotetrasiloxane steam is thermally hydrolyzed in the flame of the burner to generate silicon dioxide particles, and the silicon dioxide particles are continuously laminated and deposited on the target surface rotating around the self longitudinal axis in the vertical deposition furnace to obtain a quartz glass blank, and the quartz glass blank is melted to synthesize the large-size high-purity quartz glass.

The chemical deposition process for the large-size high-purity quartz glass has the advantages of simple steps and convenience in operation, overcomes the defect of high hydroxyl content in the chemical deposition process for the quartz glass in the prior art, and the prepared quartz glass blank has good density uniformity and a breathable structure, and is beneficial to removing the hydroxyl in the material in the subsequent process of melting and producing synthetic quartz glass, so that the large-size high-purity quartz glass is obtained.

Furthermore, SiCl is generally used in the prior art₄As a raw material, SiCl₄Is aToxic chemical substances can generate a large amount of hydrogen chloride gas in the production process, thereby causing environmental pollution and having potential safety hazard. The invention takes organosilicon octamethylcyclotetrasiloxane as raw material, enters an evaporator for gasification after rectification and purification, generates silica particles through thermal hydrolysis in oxyhydrogen flame and deposits the silica particles on the target surface of a target material to form a quartz glass body, toxic chemicals are not used from the raw material to the production process, the produced tail gas is carbon dioxide and water vapor, the carbon dioxide and the water vapor can be directly discharged, the pollution and the danger of toxic substance leakage caused by the traditional production process are greatly reduced, and the production cost is saved.

The high-speed gas flow generated by the reaction impacts the target material and can cause the generation of SiO₂Splashing of particles, splashed SiO₂The particles can be crystallized at the furnace mouth of the vertical deposition furnace along with the flowing of the gas, namely near the burner, and the generated crystals can fall onto the target surface of the target material under the influence of the gravity of the crystals after continuously growing to a certain degree, so that the deposition quality of the target surface of the target material is finally influenced. Therefore, a gap of 20mm is reserved between the burner and the furnace mouth, the velocity field distribution in the vertical deposition furnace is improved by introducing air from the outside, and the SiO is reduced₂The crystallization of particles at the furnace mouth is also convenient for the installation and the disassembly of the burner, and meanwhile, the problem that other impurities enter the vertical deposition furnace can not occur in the gap of 20 mm.

Further, in the chemical deposition process for the large-size high-purity quartz glass, the outer wall of the furnace body is a heat-insulating wall, the inner wall of the furnace body is a refractory wall, and the interlayer of the furnace body is an electric heating device and a circulating water cooling device.

Further, in the chemical deposition process of the large-size high-purity quartz glass, the thermal insulation wall is composed of refractory asbestos, a refractory fiber plate, a refractory castable or a refractory hollow ball; the refractory wall is composed of alumina, zirconia, silicon carbide or silicon nitride.

Furthermore, in the chemical deposition process for the large-size high-purity quartz glass, the middle part of the furnace body is provided with a plurality of air outlets.

The exhaust gas in the furnace body is discharged by arranging a plurality of exhaust outlets in the middle of the furnace body, and the pressure of the furnace opening of the vertical deposition furnace and the atmospheric pressure difference of the exhaust outlet can be controlled, so that the temperature field in the furnace is changed when the atmospheric pressure outside the furnace is changed, the target material target surface is ensured to form a stable flow field in the smoke in the furnace, silica particles are favorably and quickly, uniformly and effectively deposited on the target material target surface at high temperature, the silica particles are prevented from floating along with the smoke, and the forming quality of the quartz glass blank is ensured.

Further, in the above chemical deposition process for large-size high-purity silica glass, the first oxygen loop consists of a large oxygen loop, and the large oxygen loop is arranged around the central loop; the oxygen loop II and the oxygen loop III are respectively composed of a plurality of small oxygen loops, and the small oxygen loops are arranged at equal angles; the first hydrogen loop and the second hydrogen loop are respectively composed of a plurality of small hydrogen loops, and the small hydrogen loops are arranged at equal angles.

Further, in the chemical deposition process for large-size high-purity quartz glass, the central loop is connected with an oxygen pipeline and an evaporator pipeline, the first oxygen loop and the plurality of small oxygen loops are respectively connected with the oxygen pipeline, and the small hydrogen loops are respectively connected with a hydrogen pipeline.

The structure of the burner enables the temperature in the furnace body to be distributed more uniformly, and enhances the heat exchange with surrounding fluid. The method comprises the following specific steps: introducing a mixed gas of organosilicon octamethylcyclotetrasiloxane steam and oxygen into the central loop, introducing oxygen into the first oxygen loop and the plurality of small oxygen loops, introducing hydrogen into the small hydrogen loops, spraying the gases after entering the loops from the burner, generating heat through complex chemical reaction, continuously flowing high-temperature gas carrying the heat, transferring the heat to a target surface and surrounding fluid, and finally cooling and discharging the gases through an exhaust port.

Further, in the chemical deposition process of the large-size high-purity quartz glass, the oxygen pipeline, the evaporator pipeline and the hydrogen pipeline are respectively provided with an automatic constant pressure processor (137) and a mass flow controller (138).

In order to ensure stable supply of the burner to reduce adverse effects of variations in the flow rate of the raw material on the deposition surface, automatic constant pressure treatment using an automatic constant pressure processor and automatic control using a mass flow controller are required for the hydrogen, oxygen combustion gas and silicone octamethylcyclotetrasiloxane raw material.

Compared with the prior art, the invention has the following beneficial effects:

(1) the chemical deposition process for the large-size high-purity quartz glass has the advantages of simple steps and convenience in operation, overcomes the defect of high hydroxyl content in the chemical deposition process for the quartz glass in the prior art, and the prepared quartz glass blank has good density uniformity and a breathable structure, is beneficial to removing the hydroxyl in the material in the subsequent process of melting and producing synthetic quartz glass, so that the large-size high-purity quartz glass is obtained, and has a wide application prospect;

(2) the chemical deposition process of the large-size high-purity quartz glass takes the organosilicon octamethylcyclotetrasiloxane as a raw material, the organosilicon octamethylcyclotetrasiloxane is rectified and purified and then enters an evaporator for gasification, silica particles are generated by thermal hydrolysis in oxyhydrogen flame and are deposited on a target surface to form a quartz glass body, toxic chemicals are not used from the raw material to the production process, and the produced tail gas is carbon dioxide and water vapor which can be directly discharged, so that the pollution and the toxic substance leakage danger caused by the traditional production process are greatly reduced, and the production cost is saved;

(3) according to the chemical deposition process of the large-size high-purity quartz glass, a gap of 20mm is reserved between a burner and a furnace mouth, the velocity field distribution in the vertical deposition furnace is improved by introducing air from the outside, and the reduced SiO content is obtained₂The crystallization of particles at the furnace mouth is convenient for the installation and the disassembly of the burner, and meanwhile, the problem that other impurities enter the vertical deposition furnace can not occur in a gap of 20 mm;

(4) according to the chemical deposition process of the large-size high-purity quartz glass, the structural design of the burner enables the temperature in the furnace body to be more uniformly distributed, and the heat exchange with surrounding fluid is enhanced; the hydrogen, oxygen combustion gas and the organosilicon octamethylcyclotetrasiloxane raw material are automatically processed by an automatic constant pressure processor under constant pressure and automatically controlled by a mass flow controller, so that the intelligent degree is high.

Drawings

FIG. 1 is a schematic cross-sectional view of a vertical deposition furnace for the chemical deposition process of large-size high-purity quartz glass according to the present invention;

FIG. 2 is a schematic view showing the arrangement of the burner top of the vertical deposition furnace for the chemical deposition process of large-size high-purity quartz glass according to the present invention;

in the figure: the device comprises a vertical deposition furnace 1, a furnace body 11, a furnace mouth 111, a gap 1111, a heat preservation wall 112, a refractory wall 113, an electric heating device 114, a circulating water cooling device 115, an exhaust outlet 116, a mechanical lifting and rotating device 12, a burner 13, a central loop 131, a first oxygen loop 132, a large oxygen loop 1321, a first hydrogen loop 133, a second oxygen loop 134, a small oxygen loop 1341, a second hydrogen loop 135, a small hydrogen loop 1331, a third oxygen loop 136, an automatic constant pressure processor 137, a mass flow controller 138, a moving device 14, an evaporator 2 and a target material a.

Detailed Description

The technical solutions in the embodiments of the present invention will be described in detail and fully with reference to the following drawings 1-2, which are made to show specific experimental data. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The following example provides a chemical deposition process for large-sized high-purity quartz glass.