One-way flow guide type high-purity quartz continuous melting furnace

Abstract

The invention discloses a one-way flow guide type high-purity quartz continuous melting furnace which comprises a zirconium oxide base, a tungsten crucible, an aluminum oxide structural part and a zirconium oxide cover plate, a steel plate heat preservation layer is assembled on the upper portion of the zirconium oxide base, a T-shaped boron nitride ceramic insulation sleeve is inserted into the zirconium oxide base, and a molybdenum base is placed on the tungsten crucible and located on the upper portion of the zirconium oxide base. The tungsten crucible is assembled on the molybdenum base, an aluminum silicate wool heat preservation layer, an aluminum oxide heat preservation layer, a magnesium oxide powder heat preservation layer and a zirconium oxide heat preservation layer are sequentially arranged between the inner wall of the steel plate heat preservation layer and the outer wall of the tungsten crucible from outside to inside, a heat flow guiding mode is adopted, thermocouple temperature measurement and European meter temperature control are combined, and directional radiation of heat flow is achieved. The energy utilization rate is improved, and the production cost is reduced; the protective atmosphere is filled from top to bottom, the filling uniformity is good, the gas loss is small, the heating body can be completely and effectively protected, and the service life of equipment is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of advanced ceramics, in particular to a unidirectional flow-conducting high-purity quartz continuous melting furnace. Background Art

[0002] Due to its unique molecular chain structure, lattice shape and lattice change law, high-purity quartz has excellent chemical stability, extremely low volume expansion coefficient, extremely high temperature resistance, high insulation and voltage resistance, low and stable ultrasonic delay performance, mechanical properties higher than ordinary glass, ultraviolet spectrum transmission performance, visible light and near-infrared spectrum transmission performance, and occupies a pivotal position in the fields of semiconductors, photovoltaics, optical fibers, and electric light sources.

[0003] At present, the preparation of high-purity quartz is mainly to melt the powdered quartz raw materials in the crucible by electric heating, and then quickly cool it to form quartz glass. During the melting process, the structure of the quartz crystal undergoes a transformation from β-quartz to α-quartz, and then to α-cristobalite (accompanied by the generation of an amorphous phase), until the quartz melt begins to form when heated to about 1723°C.

[0004] In the existing technical solutions, ordinary continuous melting furnaces do not have temperature control programs. Some high-purity quartz manufacturers control the furnace chamber temperature based on manual adjustment, observe the material status with the naked eye, and adjust the production process, resulting in poor product stability and low yield. In addition, some continuous melting furnaces do not have a thermal insulation structure design, and usually use a single zirconium oxide thermal insulation structure, which has poor thermal insulation effect and serious furnace temperature loss. In addition, the inert protection method of inline air intake cannot protect all positions of the heating body, and there is oxidation at the edge of the heating body, which cannot achieve long-term service of the equipment and has extremely high maintenance costs.

[0005] In order to solve the technical problems of low energy utilization rate, poor cavity temperature control stability, poor furnace insulation structure, oxidation of heating body edge and so on in quartz continuous melting furnace, the present invention discloses a unidirectional flow-conducting high-purity quartz continuous melting furnace. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention discloses a unidirectional flow-conducting high-purity quartz continuous melting furnace, which adopts a heat flow guiding method, combines thermocouple temperature measurement and Europian temperature control, realizes directional radiation of heat flow, improves energy utilization and reduces production costs.

[0007] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: a one-way flow-conducting high-purity quartz continuous melting furnace, the high-purity quartz continuous melting furnace comprises a zirconia base, a tungsten crucible, an alumina structural member, and a zirconia cover plate, a steel plate insulation layer is assembled on the upper part of the zirconia base, a T-shaped boron nitride ceramic insulating sleeve is inserted into the zirconia base, a molybdenum base is placed on the upper part of the zirconia base of the tungsten crucible, the tungsten crucible is assembled on the molybdenum base, an aluminum silicate wool insulation layer, an alumina insulation layer, a magnesium oxide powder insulation layer, and a zirconia insulation layer are sequentially arranged between the inner wall of the steel plate insulation layer and the outer wall of the tungsten crucible from the outside to the inside, and the bottom of the magnesium oxide powder insulation layer is surrounded and assembled by the alumina insulation layer, a boron nitride powder layer is filled between the zirconia insulation layer and the outer wall of the tungsten crucible, and the boron nitride powder layer is filled between the zirconia insulation layer and the outer wall of the tungsten crucible. Tungsten heating rods are distributed inside the powder layer along the axial direction of the tungsten crucible. The tungsten heating rods are installed in a circumferential limit direction on the outer wall of the tungsten crucible. The top between the tungsten crucible and the zirconia insulation layer is arranged with a zirconia cover plate, so that the connection between the tungsten crucible and the zirconia insulation layer is sealed and installed through the zirconia cover plate. The outer wall of the zirconia cover plate is assembled with an alumina cover plate. An aluminum silicate wool anvil is arranged between the alumina cover plate and the steel plate insulation layer. The upper part of the aluminum silicate wool anvil is packaged by the steel cover plate. The steel cover plate is assembled and packaged with the top of the steel plate insulation layer. The top between the zirconia cover plate and the alumina cover plate is arranged with an alumina structural part. The alumina structural part is coaxially arranged with the tungsten crucible. A nitrogen pipe and a thermocouple are arranged on the alumina structural part. A zirconia plug and a steel plate baffle are installed at the discharge port end of the zirconia base.

[0008] Preferably, the outer wall of the alumina structural member is equipped with an alumina steel plate insulation layer.

[0009] Preferably, the tungsten heating rod is of split structure and evenly distributed around the outer wall of the tungsten crucible, and the tungsten heating rod is a non-uniform heating component.

[0010] Preferably, the structure of the tungsten heating rod is arranged to be thick at the top and thin at the bottom, and the outer diameter size is distributed in a gradient decreasing manner.

[0011] Preferably, the structure of the tungsten heating rod is distributed into three sections: upper, middle and lower, and the ratio of the top outer diameter dimensions of the three parts is 0.4:0.3:0.3, among which the middle section of the tungsten heating rod is: the outer diameter dimension from the top to the bottom has no diameter difference distribution, and the outer diameter dimensions of the upper section and the lower section are uniformly decreasing from the top to the bottom, so as to form a gradient heat flow in the tungsten heating rod, so that the quartz material in the tungsten crucible can be softened quickly.

[0012] Preferably, the thermocouple is a tungsten-rhenium thermocouple, and two thermocouples are arranged at the middle height section of the high-purity quartz continuous melting furnace. The thermocouple is used to measure and control the temperature inside the furnace, and the distance between the thermocouple and the tungsten heating rod is 10 mm to 50 mm.

[0013] Preferably, the thermocouple is equipped with a Europian meter, the tungsten heating rod is equipped with electrodes, and is powered externally.

[0014] Preferably, the inlet gas used in the nitrogen pipe during the application process is hydrogen gas in nitrogen.

[0015] Preferably, the material used for the zirconia thermal insulation layer is yttria-stabilized cubic zirconia ceramic.

[0016] Preferably, the periphery of the zirconium oxide base is equipped with a steel plate chamber.

[0017] In summary, the present invention provides a unidirectional flow-conducting high-purity quartz continuous melting furnace. Compared with the prior art, the present invention has the following advantages:

[0018] ① Energy saving. The one-way flow-guiding heating structure used makes the thermal field have a temperature gradient, so that the accumulated materials can complete the melting process better and reduce heat loss;

[0019] ② The present invention has no pollution to the materials. The tungsten used in the present invention is the heating body, and the heating body does not come into contact with the materials. Compared with the traditional intervention heating method, the present invention has no pollution to the materials and significantly improves the utilization rate of the raw materials;

[0020] ③ The present invention introduces a Eurotherm meter to control the heating temperature of the equipment, and the temperature fluctuation range is ±0.3°C. Compared with the original manually adjusted temperature control method or PLC type electric heating system, the equipment of the present invention has better uniformity and high product stability, which solves the problem of poor stability of the same batch of high-purity quartz materials;

[0021] ④ The protective atmosphere of the present invention is filled from top to bottom, with good filling uniformity and small gas loss, which can effectively protect the heating body and improve the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the quartz continuous melting furnace of the present invention;

[0023] Figure 2 is a schematic diagram of the structure of the non-uniform heating body of the present invention, from which it can be clearly seen that the heating body is divided into three parts;

[0024] Figure 3 It is a schematic diagram of the structure of the non-uniform heating body of the present invention, wherein the extended end portion is used for connecting the electrode;

[0025] Figure 4 It is a schematic diagram of the internal analysis structure of the quartz continuous melting furnace of the present invention;

[0026] Figure 5 The present invention Figure 4 Schematic diagram of the connection between the tungsten crucible, boron nitride powder layer, tungsten crucible and tungsten heating rod at C in the middle;

[0027] Figure 6 The present invention Figure 4 Schematic diagram of the structure of the tungsten crucible and the tungsten heating rod at D in the middle being transferred in the lower part;

[0028] Figure 7 The present invention Figure 4 Schematic diagram of the assembly structure of the zirconia base and the tungsten heating rod at E in the middle;

[0029] Figure 8 The present invention Figure 4 Schematic diagram of the cross-sectional structure along the F direction;

[0030] Fig. 9 The present invention Figure 1 Schematic diagram of the flange structure at G in the middle;

[0031] Fig.10 The present invention Figure 1 Schematic diagram of the copper electrode arm, thermocouple, and steel plate insulation layer structure at H in the middle;

[0032] In the figure: alumina structural part 1, zirconia cover plate 2, alumina cover plate 3, aluminum silicate wool anvil 4, steel cover plate 5, steel plate insulation layer 6, aluminum silicate wool insulation layer 7, magnesium oxide powder insulation layer 8, alumina insulation layer 9, zirconium oxide insulation layer 11, tungsten crucible 12, boron nitride powder layer 13, zirconia plug 14, thermocouple 15, zirconia base 16, steel plate cabin 17, nitrogen pipe 18, T-shaped boron nitride ceramic insulating sleeve 20, molybdenum base 22, tungsten heating rod 24, alumina steel plate insulation layer 26, flange 30, copper electrode arm 31, steel plate baffle 32. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] like Figures 1 to 10 As shown:

[0035] The present invention is a unidirectional flow-conducting high-purity quartz continuous melting furnace, which comprises a zirconia base 16, a tungsten crucible 12, an alumina structural member 1, and a zirconia cover plate;

[0036] In order to solve the technical problems of low energy utilization rate, poor cavity temperature control stability, poor furnace insulation structure, oxidation of the edge of the heating body, etc. in the quartz continuous melting furnace, the technical method adopted by the present invention is as follows: the quartz continuous melting furnace adopts upper and lower parts to be transferred and fixed by flanges, and the top steel plate insulation layer 6 of the quartz continuous melting furnace is assembled with a steel plate cover 5 by flanges;

[0037] First, assemble the lower half of the quartz continuous melting furnace: with the zirconia base 16 as a reference, assemble the lower half of the steel plate insulation layer 6 with the zirconia base 16; the bottom discharge port end of the zirconia base 16 is equipped with a zirconia plug 14 and a steel plate baffle 32, insert six T-shaped boron nitride ceramic insulating sleeves 20 into the zirconia base 16, place the molybdenum base 22 supporting the tungsten crucible 12 on the zirconia base 16, assemble the alumina bottom insulation layer 9, place the tungsten crucible 12 on the molybdenum base 22, assemble the lower half of the zirconia insulation layer 11, and at the same time, put the lower half of the boron nitride powder 13 between the zirconia insulation layer 11 and the tungsten crucible 12, assemble the heating rod 24 along the axial direction of the tungsten crucible 12, and install it around the axial direction of the tungsten crucible 12 by limiting.

[0038] Fill the aluminum silicate wool insulation layer 7 between the steel plate insulation layer 6 and the aluminum oxide insulation layer 9, fill the magnesium oxide powder insulation layer 8 between the aluminum oxide insulation layer 9 and the zirconium oxide insulation layer 11, the bottom of the magnesium oxide powder insulation layer 8 is surrounded and assembled by the aluminum oxide insulation layer 9, fill the boron nitride powder layer 13 between the zirconium oxide insulation layer 11 and the tungsten crucible 12, and the inside of the boron nitride powder layer 13 is distributed with tungsten heating rods 24 along the axial direction of the tungsten crucible 12, and the tungsten heating rods 24 are installed in the circumferential limit direction of the outer wall of the tungsten crucible 12 to form the assembly layer sequence of the lower half of the quartz continuous melting furnace: the aluminum silicate wool insulation layer 7, the aluminum oxide insulation layer 9, the magnesium oxide powder insulation layer 8, and the zirconium oxide insulation layer 11 are arranged in sequence from the outside to the inside between the steel plate insulation layer 6 and the tungsten crucible 12, and then install the thermocouple 15 of the lower half part in the lower half of the quartz continuous melting furnace;

[0039] The upper and lower parts of the quartz continuous melting furnace are fixedly installed by flanges, and the upper and lower parts of the quartz continuous melting furnace have the same internal layer number relationship; the difference is that: the upper part of the quartz continuous melting furnace is encapsulated between the top of the tungsten crucible 12 and the zirconia insulation layer 11 through the zirconia cover plate 2, the outer wall of the zirconia cover plate 2 is assembled with an alumina cover plate 3, and an aluminum silicate wool anvil 4 is arranged between the alumina cover plate 3 and the steel plate insulation layer 6, the upper part of the aluminum silicate wool anvil 4 is encapsulated by the steel cover plate 5, and the steel cover plate 5 is assembled and encapsulated with the top of the steel plate insulation layer 6, the top between the zirconia cover plate 2 and the alumina cover plate 3 is arranged with an alumina structural member 1, the alumina structural member 1 is coaxially arranged with the tungsten crucible 12, and the alumina A nitrogen pipe 18 and a thermocouple 15 are provided on the structural member 1; the technical problems of low energy utilization, poor stability of cavity temperature control, poor furnace insulation structure, oxidation at the edge of the heating body, etc. are solved, and a stable insulation effect and high energy utilization are achieved through a multi-layer insulation structure. The nitrogen pipe 18 and the thermocouple 15 are used to achieve small gas loss, and the heating body can be effectively protected completely, thereby improving the service life of the equipment and achieving stable cavity temperature control. The upper part of the quartz continuous melting furnace is encapsulated by the zirconium oxide cover plate 2, the alumina cover plate 3, the aluminum silicate wool anvil 4 and the steel cover plate 5, so as to achieve oxidation barrier at the edge of the heating body and realize the long-term use characteristics of the equipment.

[0040] In at least one embodiment, an alumina steel plate insulation layer 26 is installed on the outer wall of the alumina structural member 1 to increase the insulation effect of the alumina structural member 1 and improve the use efficiency of the equipment.

[0041] In at least one embodiment, the tungsten heating rods 24 are split in structure and evenly distributed around the outer wall of the tungsten crucible 12 . The tungsten heating rods are non-uniform heating components, thereby forming a gradient heat flow, which helps to achieve rapid softening of the quartz material.

[0042] In at least one embodiment, further, the structure of the tungsten heating rod 24 is configured to be thick at the top and thin at the bottom, and the outer diameter is distributed in a gradient decreasing manner, so as to achieve directional radiation of heat flow, improve energy utilization, and reduce production costs.

[0043] In at least one embodiment, the structure of the tungsten heating rod 24 is distributed into three sections: upper, middle and lower, and the ratio of the top outer diameter dimensions of the three sections is 0.4:0.3:0.3, wherein the middle section of the tungsten heating rod 24 is: its top outer diameter dimension to the bottom outer diameter dimension has no diameter difference distribution, and the upper section and the lower section have outer diameter dimensions uniformly decreasing from the top to the bottom, so as to form a gradient heat flow of the tungsten heating rod 24, so that the quartz material in the tungsten crucible 12 is quickly softened, the energy utilization rate is improved, the production cost is reduced, and a unidirectional flow-conducting heating structure is realized, so that the thermal field has a temperature gradient, so that the deposited materials can better complete the melting process and reduce heat loss.

[0044] In at least one embodiment, the thermocouple 15 is a tungsten-rhenium thermocouple. Two thermocouples 15 are arranged at the middle height section of the high-purity quartz continuous melting furnace. The thermocouple 15 is used to measure and control the temperature inside the furnace body, and the distance between the thermocouple 15 and the tungsten heating rod 24 is 10 mm to 50 mm.

[0045] Specifically: the upper thermocouple 15 is installed at the upper part of the heating body, and the distance from the middle heating body is 10 to 50 mm, preferably 30 mm; the lower thermocouple 15 is installed at the lower part of the heating body, and the distance from the middle heating body is 10 to 50 mm, preferably 50 mm; the upper thermocouple 15 is used to measure the temperature inside the furnace body, and the lower thermocouple 15 is used to control the temperature of the furnace cavity, and the temperature control device matched with the thermocouple 15 is a European table;

[0046] In at least one embodiment, the thermocouple 15 is equipped with a Europometer, and the tungsten heating rod 24 is equipped with electrodes and powered by an external power supply. Specifically, the copper electrode arm is assembled on the steel plate and connected to the molybdenum electrode, the tungsten heating rod 24 is assembled with the molybdenum electrode, the Europometer is connected to the thermocouple 15, and powered by an external power supply, so that the preparation for the continuous melting furnace can be completed.

[0047] In at least one embodiment, the inlet gas used in the nitrogen pipe 18 during the application process is hydrogen gas in nitrogen to achieve oxidation resistance of the heating body tungsten heating rod 24 and reduce greenhouse gas emissions of the equipment.

[0048] In at least one embodiment, the material used for the zirconia thermal insulation layer 11 is yttria-stabilized cubic zirconia ceramics, so as to achieve stable performance at high temperatures and improve high-strength performance.

[0049] In at least one embodiment, the periphery of the zirconium oxide base 16 is assembled with a steel plate chamber 17 .

[0050] The embodiments of the present invention are only used to illustrate the present invention and do not constitute a limitation on the scope of the claims. Other substantially equivalent substitutes that can be thought of by those skilled in the art are all within the protection scope of the present invention.

Claims

1. A one-way flow-conducting high-purity quartz continuous melting furnace, characterized in that: The high-purity quartz continuous melting furnace comprises a zirconia base (16), a tungsten crucible (12), an alumina structural member (1), and a zirconia cover plate. A steel plate insulation layer (6) is installed on the upper part of the zirconia base (16). A T-shaped boron nitride ceramic insulating sleeve (20) is inserted into the zirconia base (16). A molybdenum base (22) is placed on the upper part of the zirconia base (16) of the tungsten crucible (12). The tungsten crucible (12) is installed on the molybdenum base (22). The inner wall of the steel plate insulation layer (6) is connected to the inner wall of the tungsten crucible (12). 2) are sequentially arranged from outside to inside between the outer walls thereof, an aluminum silicate wool insulation layer (7), an aluminum oxide insulation layer (9), a magnesium oxide powder insulation layer (8), and a zirconium oxide insulation layer (11), and the bottom of the magnesium oxide powder insulation layer (8) is surrounded and assembled by the aluminum oxide insulation layer (9), a boron nitride powder layer (13) is filled between the zirconium oxide insulation layer (11) and the outer wall of the tungsten crucible (12), and a tungsten heating rod (20) is distributed inside the boron nitride powder layer (13) along the axial direction of the tungsten crucible (12). 4), a tungsten heating rod (24) is installed in a circumferential limit direction on the outer wall of the tungsten crucible (12), a zirconia cover plate (2) is arranged at the top between the tungsten crucible (12) and the zirconia insulation layer (11), and the connection between the tungsten crucible (12) and the zirconia insulation layer (11) is sealed and installed through the zirconia cover plate (2), the outer wall of the zirconia cover plate (2) is equipped with an aluminum oxide cover plate (3), and an aluminum silicate wool anvil (4) is arranged between the aluminum oxide cover plate (3) and the steel plate insulation layer (6), and the aluminum silicate wool anvil (4) is arranged between the aluminum oxide cover plate (3) and the steel plate insulation layer (6). The upper part of the cotton anvil (4) is encapsulated by a steel cover plate (5), and the steel cover plate (5) is assembled and encapsulated with the top of the steel plate insulation layer (6). The top between the zirconium oxide cover plate (2) and the aluminum oxide cover plate (3) is provided with an aluminum oxide structural member (1), and the aluminum oxide structural member (1) is coaxially arranged with a tungsten crucible (12). A nitrogen pipe (18) and a thermocouple (15) are arranged on the aluminum oxide structural member (1), and a zirconium oxide plug (14) and a steel plate baffle (32) are installed at the discharge port end of the zirconium oxide base (16).

2. A one-way flow-conducting high-purity quartz continuous melting furnace according to claim 1, characterized in that: The outer wall of the alumina structural member (1) is provided with an alumina steel plate insulation layer (26).

3. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 1, characterized in that: The tungsten heating rod (24) is of split structure and evenly distributed around the outer wall of the tungsten crucible (12), and is a non-uniform heating component.

4. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 3, characterized in that: The structure of the tungsten heating rod (24) is arranged to be thick at the top and thin at the bottom, and the outer diameter thereof decreases in a gradient distribution.

5. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 3, characterized in that: The structure of the tungsten heating rod (24) is distributed into three sections: upper, middle and lower, and the ratio of the top outer diameters of the three sections is 0.4:0.3:0.3, wherein the middle section of the tungsten heating rod (24) has no diameter difference distribution from the top outer diameter to the bottom outer diameter, and the top section and the lower section have uniform decreasing outer diameters from the top to the bottom, so as to form a gradient heat flow of the tungsten heating rod (24) to quickly soften the quartz material in the tungsten crucible (12).

6. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 1, characterized in that: The thermocouple (15) is a tungsten-rhenium thermocouple. Two thermocouples (15) are arranged at the middle section of the height of the high-purity quartz continuous melting furnace. The thermocouple (15) is used to measure and control the temperature inside the furnace body. The distance between the thermocouple (15) and the tungsten heating rod (24) is 10 mm to 50 mm.

7. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 6, characterized in that: The thermocouple (15) is equipped with a Europian meter, and the tungsten heating rod (24) is equipped with electrodes and powered by an external power supply.

8. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 1, characterized in that: The inlet gas used in the nitrogen pipe (18) during the application process is hydrogen gas in nitrogen.

9. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 1, characterized in that: The material used for the zirconium oxide thermal insulation layer (11) is cubic phase zirconium oxide ceramics stabilized by yttria.

10. The one-way flow-conducting high-purity quartz continuous melting furnace according to claim 1, characterized in that: The periphery of the zirconium oxide base (16) is equipped with a steel plate chamber (17).

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