A sintering apparatus and method for synthesizing quartz powder rods

Abstract

This application belongs to the field of quartz material preparation, specifically disclosing a sintering apparatus and method for synthesizing quartz powder rods. The apparatus includes a furnace core tube, a vertical rod feeding mechanism, and segmented independent temperature control components. Multiple air inlets and exhaust outlets are respectively arranged on both sides of the furnace core tube. Each air inlet is connected to an independently controlled gas supply component, which provides a first gas as a protective gas, a second gas for dehydroxylation of the quartz powder rods, and a third gas to aid sintering. The segmented independent temperature control components include a control module and multiple temperature control modules. The multiple temperature control modules are spaced apart along the axial direction of the furnace core tube and are all electrically connected to the control module. The interval between two adjacent temperature control modules forms a heating gap. Through the structural design of this application, the sintering uniformity and quality consistency of large-size synthetic quartz powder rods in both the longitudinal and radial directions are effectively improved.

Description

Technical Field

[0001] This application belongs to the field of quartz material preparation, and more specifically, relates to a sintering apparatus and method for synthesizing quartz powder rods. Background Technology

[0002] Synthetic quartz powder rods are the core precursor substrates for preparing high-purity quartz glass, optical fiber preforms, semiconductor vacuum quartz cavities, and deep ultraviolet optical components. The hydroxyl content and longitudinal and radial distribution uniformity within the matrix material after sintering directly determine the refractive index consistency, high-temperature crystallization resistance, and deep ultraviolet light transmittance of the finished product, making them core control indicators for the mass production of high-end quartz devices. Currently, in the semiconductor and photolithography optics fields, it is required that the longitudinal hydroxyl content of ultra-long quartz matrix materials fluctuate by ≤1ppm, and the longitudinal powder sintering temperature difference be ≤±2℃, placing extremely high demands on the bidirectional uniformity of the atmosphere and temperature field within the tube.

[0003] In related technologies, existing vertical sintering equipment generally adopts a vertical through-flow structure with a single-port centralized air intake at the bottom and a single-port centralized air outlet at the top. The gas inside the tube flows unidirectionally from bottom to top. Due to the combined effects of gas consumption along the process and thermal convection upward floating, a longitudinal atmosphere gradient is easily formed with an abundant atmosphere at the bottom and a deficient atmosphere at the top. Combined with the traditional single-hole direct injection air intake method, the radial atmosphere stratification of the furnace tube is more obvious, and there are differences in the degree of dehydroxylation and sintering between the core and surface of the powder rod. The consistency of longitudinal and radial hydroxyl parameters is poor. Meanwhile, due to the natural upward movement of heat in vertical furnaces, residual heat accumulates and temperatures are higher in the upper part of the tube, while heat dissipates faster and temperatures are lower in the lower part, easily forming an inherent temperature gradient that decreases from top to bottom. Existing equipment mostly uses integrated heating and lacks segmented independent temperature control capabilities. Temperature measurement relies mainly on indirect measurement through the furnace wall, making it difficult to match the actual sintering temperature of the powder and to offset the longitudinal temperature difference caused by the upward movement of hot air. Furthermore, existing powder rods mostly use a static fixed sintering mode, which easily creates low-temperature heating blind spots in the heater interval area, resulting in uneven local sintering of the powder rods. At the same time, the fixed placement of the powder rods and their long-term one-sided reception of the furnace heat source result in radial heating temperature differences, further affecting the consistency of longitudinal and radial sintering quality of the powder rods. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a sintering apparatus and method for synthesizing quartz powder rods, aiming to solve the problems of uneven vertical unidirectional airflow distribution, longitudinal temperature field gradient caused by hot gas rising, and uneven longitudinal and axial hydroxyl distribution in the product, which affect the sintering effect of the powder rods in existing vertical sintering equipment.

[0005] This application provides a sintering apparatus for synthetic quartz powder rods, specifically including a furnace core tube, a vertical rod feeding mechanism, and a segmented independent temperature control component; the furnace core tube is provided with multiple air inlets and exhaust outlets on both sides, and each air inlet is connected to an independently controlled gas supply component, which is used to provide a first gas as a protective gas, a second gas for dehydroxylation of the quartz powder rods, and a third gas to aid sintering; The segmented independent temperature control assembly includes a control module and multiple temperature control modules. The multiple temperature control modules are arranged at intervals along the axial direction of the furnace core tube and are all electrically connected to the control module. The interval between two adjacent temperature control modules forms a heating gap. The vertical rod feeding mechanism includes a linear drive and a rotary drive. The linear drive is connected to an external carrier, and the rotary drive is located at the output end of the linear drive. The quartz powder rod is connected to the output end of the rotary drive and is located on the same axis as the furnace core tube. The rotary drive is used to drive the quartz powder rod to rotate around its own axis, and the linear drive is used to drive the rotary drive and the quartz powder rod to reciprocate along the axial direction of the furnace core tube. The maximum displacement distance of the quartz powder rod is not less than the length of the heating gap.

[0006] Compared with the prior art, the above-described technical solution conceived in this application, by employing multiple temperature control modules spaced apart along the axial direction of the furnace core tube to independently control the temperature of each temperature zone, and cooperating with independent gas supply from each air inlet, effectively suppresses the longitudinal temperature gradient caused by the upward floating of hot gas inside the furnace core tube, making the longitudinal temperature distribution inside the tube more uniform; at the same time, by driving the powder rod to maintain its rotation and reciprocate along the axial direction of the furnace core tube throughout the sintering process through the vertical rod feeding mechanism, the powder rod alternately crosses the heating gap between adjacent temperature control modules, and the rotational motion improves the problem of unilateral heating in the circumferential direction of the powder rod, significantly weakening the influence of the heating blind zone on the sintering uniformity, thereby effectively improving the sintering uniformity and quality consistency of large-size synthetic quartz powder rods in both the longitudinal and radial directions.

[0007] As a further preferred embodiment, the furnace core tube is an infrared transparent quartz glass tube with a hydroxyl content of no more than 1 ppm, and the inner wall of the furnace core tube is coated with a high-temperature resistant alumina infrared light-transmitting protective coating.

[0008] As a further preferred embodiment, each of the multiple air inlets is provided with a pressure stabilizing channel, and each end face of the pressure stabilizing channel is provided with a number of breathable micropores around the center.

[0009] As a further preferred embodiment, each of the exhaust ports is fixedly connected to a quartz cylindrical window, the hydroxyl content of the quartz cylindrical window is not greater than 0.5 ppm, and an online detector is provided on the quartz cylindrical window. The online detector is electrically connected to the control module and is used to perform in-situ online detection of exhaust components.

[0010] As a further preferred embodiment, the temperature control module includes a heating unit and a powder temperature detector. Both the heating unit and the powder temperature detector are fixedly connected to the furnace core tube and electrically connected to the control module. The powder temperature detector is arranged perpendicular to the outer wall of the quartz powder rod and is used to collect the sintering temperature of the powder surface at the corresponding position and feed the temperature data back to the control module. The control module independently adjusts the output power of the corresponding heating unit according to the measured temperature of each powder temperature detector.

[0011] As a further preferred embodiment, the gas supply assembly includes a helium gas supply unit, a chlorine gas supply unit, and an oxygen gas supply unit. The helium gas supply unit, the chlorine gas supply unit, and the oxygen gas supply unit are all electrically connected to the control module. The control module is used to independently adjust the gas supply flow rate of each of the helium gas supply unit, the chlorine gas supply unit, and the oxygen gas supply unit corresponding to each gas inlet.

[0012] As a further preferred embodiment, along the furnace core tube from bottom to top, the helium gas flow rate of each of the gas inlets decreases gradually in a gradient and remains constant throughout the sintering process; along the furnace core tube from bottom to top, the initial oxygen gas flow rate and the initial chlorine gas flow rate of each of the gas inlets decrease gradually in a gradient, and the control module can adjust the oxygen gas flow rate and the chlorine gas flow rate corresponding to each of the gas inlets during the sintering process.

[0013] As a further preferred embodiment, the linear drive unit drives the quartz powder rod to reciprocate along the axis of the furnace core tube at a speed of 0 to 20 mm / min; the rotary drive unit drives the quartz powder rod to rotate at a speed of 1 r / min to 20 r / min.

[0014] As a further preferred embodiment, the number of air inlets and air outlets is the same, and each air inlet and a corresponding air outlet are arranged opposite to each other in the radial direction of the furnace core tube.

[0015] This application also provides a method for sintering synthetic quartz powder rods, using the above-mentioned apparatus, comprising the following steps: S1. Install the quartz powder rod at the output end of the vertical feeding mechanism, so that the quartz powder rod is located inside the furnace core tube. After sealing the tube, the quartz powder rod is preheated by the segmented independent temperature control components. At the same time, the initial gas flow of each gas supply component is distributed in a manner that gradually decreases from bottom to top according to the flow rate of each gas inlet. The vertical feeding mechanism drives the quartz powder rod to rotate and reciprocate along the axis of the furnace core tube throughout the subsequent sintering process. S2. The tube is kept in a low temperature range by segmented independent temperature control components. The first gas and the third gas are introduced through each air inlet to preheat, dehydrate and remove impurities from the quartz powder rod. S3. The tube is heated to the medium temperature range by segmented independent temperature control components. The first gas, the second gas and the third gas are introduced through each air inlet to perform slow shrinkage and hydroxyl control treatment on the preheated, dehydrated and initially impurity-removed quartz powder rod. S4. The tube is heated to a high temperature range by segmented independent temperature control components. The first gas and the third gas are introduced through each air inlet to sinter and shape the quartz powder rod after slow shrinkage and controlled hydroxyl treatment, thus completing the sintering of the quartz powder rod.

[0016] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages: 1. This application employs multiple temperature control modules spaced along the axial direction of the furnace core tube to independently control the temperature of each zone. Combined with independent gas supply to each inlet and a gradient gas supply method that decreases progressively from bottom to top, this effectively suppresses the longitudinal temperature gradient caused by the upward movement of hot gas within the furnace core tube, resulting in a more uniform longitudinal temperature distribution. Simultaneously, a vertical feeding mechanism drives the powder rod to rotate and reciprocate along the axial direction of the furnace core tube throughout the sintering process. This allows different parts of the powder rod to alternately cross the heating gaps between adjacent temperature control modules. The rotational motion improves the problem of unilateral heating in the circumferential direction of the powder rod, significantly reducing the impact of the heating blind zone on sintering uniformity. Furthermore, the gas inlets and outlets positioned opposite each other on both sides of the furnace core tube, along with the coordinated adjustment of online detectors and control modules for each zone, achieve real-time feedback and precise control of the exhaust component concentration in each longitudinal zone within the tube. This proactively optimizes the longitudinal and radial hydroxyl distribution deviation of the powder rod during sintering, thereby significantly improving the sintering uniformity and quality consistency of large-size synthetic quartz powder rods in both the longitudinal and radial directions.

[0017] 2. This application achieves uniform gas distribution by setting a pressure-stabilizing channel at the air inlet and using micron-level permeable micropores, ensuring a uniform flow rate of the process gas entering the furnace core tube without jet impact. This effectively avoids the impact of local airflow disturbance on the sintering quality of the powder rod surface. Low-hydroxyl quartz cylindrical windows are set at each exhaust port and used in conjunction with online detectors for in-situ real-time detection, solving the problem of lag in traditional sampling and detection. This provides real-time and accurate data support for closed-loop control. At the same time, the low-hydroxyl window material avoids water peak interference in the detection optical path, ensuring detection accuracy.

[0018] 3. This application achieves precise and independent temperature control of each temperature zone by independently configuring heating units and powder temperature detectors in each temperature control module. The control module independently adjusts the power of the corresponding heating unit according to the actual temperature measured by each detector, effectively compensating for the longitudinal temperature deviation caused by the upward movement of hot gas. The helium supply method of each inlet gradually decreasing from bottom to top and remaining constant throughout the process, combined with the initial gradient decrease of oxygen and chlorine and independent dynamic adjustment of each zone during sintering, further optimizes the matching of the longitudinal airflow field and the concentration field of the reaction components in the tube, effectively avoiding longitudinal hydroxyl gradient deviation.

[0019] 4. In this application, the gas supply component integrates three independent gas supply units and is independently adjusted by the control module. Combined with the rotation speed and reciprocating speed of the rod feeding mechanism, it realizes the multi-field coordinated matching of temperature field, airflow field, reaction component field and powder rod movement trajectory. The radially opposite setting of the inlet and outlet ensures that the airflow in each zone penetrates the powder rod surface laterally and is discharged evenly. Combined with the rotational motion, the points on the circumferential surface of the powder rod alternately face the inlet and outlet, further improving the radial sintering uniformity. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the sintering apparatus provided in the embodiments of this application; Figure 2 This is a side view of the voltage regulation channel structure provided in the embodiment of this application; Figure 3 This is a schematic diagram of the overall structure of the segmented independent temperature control component provided in the embodiments of this application; Figure 4 This is a schematic diagram of the overall structure of the temperature control module provided in the embodiments of this application; Figure 5 This is a graph showing the hydroxyl content test curves of the quartz powder rods of Example 1 and Comparative Example 1 in the length direction of this application.

[0021] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Furnace core tube; 11. Air inlet; 12. Exhaust outlet; 13. Pressure stabilizing channel; 131. Ventilation micropores; 14. Quartz cylinder window; 15. Online detector; 2. Vertical rod feeding mechanism; 21. Linear drive component; 22. Rotary drive component; 3. Segmented independent temperature control assembly; 31. Control module; 32. Temperature control module; 321. Heating unit; 322. Powder temperature detector; 4. Gas supply assembly; 41. Helium gas supply unit; 42. Chlorine gas supply unit; 43. Oxygen gas supply unit; 5. Quartz powder rod. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] Reference Figure 1This application discloses a sintering apparatus for synthesizing quartz powder rods 5, comprising a furnace core tube 1, a vertical rod feeding mechanism 2, and a segmented independent temperature control assembly 3. The furnace core tube 1, serving as the main container for the sintering reaction, is vertically arranged, with multiple air inlets 11 and exhaust ports 12 equidistantly spaced along its axial direction on both sides. The air inlets 11 are used to introduce various process gases into the furnace core tube 1, and the exhaust ports 12 are used to discharge the tail gas after the reaction. Each air inlet 11 is connected to an independently controllable gas supply assembly 4, which provides a first gas as a protective gas, a second gas for dehydroxylation of the quartz powder rods, and a third gas to aid sintering. By independently controlling the gas supply to each air inlet 11, the longitudinal temperature gradient caused by the upward movement of hot gas within the furnace core tube 1 is effectively suppressed, making the longitudinal temperature distribution within the tube more uniform. This solves the problems of uneven vertical unidirectional airflow distribution and significant longitudinal temperature gradient caused by the upward movement of hot gas under traditional single-inlet methods. Meanwhile, this multi-segment independent gas supply method enables each gas inlet 11 to input process gases of different compositions and flow rates in segments along the furnace core tube 1, and adjust the process atmosphere of each segment as needed, thereby achieving refined atmosphere control of different sections of the quartz powder rod 5 and significantly reducing the non-uniformity of longitudinal hydroxyl distribution in the product.

[0024] Specifically, the furnace core tube 1 is preferably made of infrared-transparent quartz glass with a hydroxyl content of no more than 1 ppm. This low-hydroxyl quartz glass tube has good transmittance to infrared radiation, enabling the infrared heat from the heating unit 321 to efficiently penetrate the wall of the furnace core tube 1 and be transferred to the surface of the powder rod inside the tube, thereby improving heating efficiency. At the same time, the inner wall of the furnace core tube 1 is coated with a high-temperature resistant alumina infrared-transmitting protective coating. This coating can protect the quartz tube wall from corrosion by chlorine and other corrosive gases, extending the service life of the furnace core tube 1, while also maintaining high infrared transmittance to ensure effective transmission of heating radiation.

[0025] More specifically, refer to Figure 1-3The segmented independent temperature control component 3 includes a control module 31 and multiple temperature control modules 32. The control module 31 is specifically a PLC controller, and each temperature control module 32 can independently adjust its output power. Multiple temperature control modules 32 are evenly spaced along the axis of the furnace core tube 1 and are all electrically connected to the control module 31. The interval between two adjacent temperature control modules 32 forms a heating gap. Each temperature control module 32 specifically includes a heating unit 321 and a powder temperature detector 322. Both the heating unit 321 and the powder temperature detector 322 are fixedly connected to the furnace core tube 1 and are electrically linked to the control module 31. The powder temperature detector 322 is positioned perpendicular to the outer wall of the quartz powder rod 5, i.e., the detector faces the outer wall of the quartz powder rod 5 inside the furnace core tube 1, and is used to collect the sintering temperature of the powder surface at the corresponding location and feed the temperature data back to the control module 31 in real time. The control module 31 independently adjusts the output power of the corresponding heating unit 321 according to the measured temperature of each powder temperature detector 322, realizing independent closed-loop control of the temperature in each temperature zone. Through this multi-zone independent temperature control method, each temperature control module 32 can independently adjust the heating power of its corresponding zone according to the actual sintering requirements. This effectively suppresses the longitudinal temperature gradient caused by the upward movement of hot gas inside the furnace core tube 1, making the longitudinal temperature distribution inside the tube more uniform. This solves the problem of large temperature differences between the upper and lower parts of the furnace body and inconsistent longitudinal sintering effects of products caused by the upward movement of hot gas in traditional vertical sintering equipment. The control module 31 is a commonly used module in this field, and its control principle is common knowledge and will not be elaborated here.

[0026] Furthermore, the vertical rod feeding mechanism 2 is a controllable rotary lifting integrated mechanism used to drive the powder rod to rotate at a constant speed and move vertically and controllably back and forth throughout the sintering process. Specifically, it includes a linear drive component 21 and a rotary drive component 22. The linear drive component 21 can be a linear motor, and the rotary drive component 22 can be a rotary motor. The linear drive component 21 is fixedly installed on an external carrier, such as a fixed frame. The rotary drive component 22 is fixedly installed at the output end of the linear drive component 21. The quartz powder rod 5 is connected to the output end of the rotary drive component 22 and is located on the same axis as the furnace core tube 1. Specifically, a clamping component is fixedly connected to the output shaft of the rotary drive component 22, which can clamp and fix the quartz powder rod 5. The rotary drive 22 is used to drive the quartz powder rod 5 to rotate around its own axis, and the linear drive 21 is used to drive the rotary drive 22 and the quartz powder rod 5 to reciprocate along the axial direction of the furnace core tube 1. The maximum displacement distance of the quartz powder rod 5 is not less than the length of the heating gap, so that the sintering area of ​​the quartz powder rod 5 can cross the heating gap and reciprocate. During the sintering process, the rotary drive 22 drives the quartz powder rod 5 to rotate at a speed of 1 r / min to 20 r / min, and the linear drive 21 drives the quartz powder rod 5 to reciprocate along the axis of the furnace core tube 1 at a speed of 0 to 20 mm / min. The vertical rod feeding mechanism 2 drives the powder rod to maintain its rotation and reciprocate along the axis of the furnace core tube 1 throughout the sintering process, so that each part of the powder rod alternately crosses the heating gap between adjacent temperature control modules 32, reducing the time that the powder is in the heating blind zone for a long time. The rotational motion improves the problem of unilateral heating of the powder rod in the circumferential direction caused by the fixed heat source, balances the heating frequency of each position of the powder rod in the circumference, and significantly weakens the influence of the heating blind zone on the sintering uniformity. Thus, it effectively improves the sintering uniformity and quality consistency of the large-size synthetic quartz powder rod 5 in the longitudinal and radial directions, and improves the uniformity of hydroxyl removal rate in the circumference and axial direction of the powder rod.

[0027] Reference Figure 1 and Figure 2In this embodiment, a pressure-stabilizing channel 13 is fixedly connected to each of the multiple air inlets 11. The pressure-stabilizing channel 13 has a cylindrical structure, with several permeable micropores 131 around the center on both ends. This pressure-stabilizing channel 13 structure can rectify and equalize the airflow entering the furnace core tube 1, so that the process gas diffuses evenly and stably into the inner cavity of the furnace core tube 1 through the permeable micropores 131, avoiding local temperature fluctuations or powder surface erosion caused by the airflow directly blowing on the powder rod surface, and further optimizing the uniformity of the atmosphere distribution inside the tube. The right-in, left-out transverse partitioned airflow matches the high reaction activity of the upper part after the hot gas rises. Combined with the constant helium partial pressure and dynamically adjustable oxygen and chlorine gas supply mode, the oxygen and chlorine intake volume is finely adjusted based on the feedback of the partitioned exhaust gas components to offset the component deviation caused by longitudinal reaction consumption and thermal field differences, and maintain the uniformity of longitudinal exhaust component concentration inside the tube. Simultaneously, a quartz cylindrical window 14 is fixedly connected to each exhaust port 12. The hydroxyl content of this quartz cylindrical window 14 is no greater than 0.5 ppm, and the window has no intrinsic absorption peak in the 2730 nm hydroxyl characteristic absorption band, thus avoiding significant spectral detection interference. An online detector 15 is fixedly installed on the quartz cylindrical window 14, specifically an integrated reflective FTIR miniature single-probe online detector 15. This online detector 15 is electrically connected to the control module 31 and is used for in-situ online detection of exhaust components, real-time acquisition of hydroxyl, chlorine, and oxygen component concentration data inside the exhaust gas of the corresponding sintering zone. Through this online detector 15, the content of each component in the exhaust gas, including the concentration changes of byproducts such as water vapor and chlorine oxides, can be monitored in real time. The control module 31 dynamically adjusts the flow ratio of each gas supply component 4 according to the detection results, realizing closed-loop optimization control of the sintering process and ensuring that the dehydroxylation reaction and sintering process are always under optimal process conditions.

[0028] Furthermore, the gas supply assembly 4 includes a helium supply unit 41, a chlorine supply unit 42, and an oxygen supply unit 43, which respectively control the intake flow of helium, oxygen, and chlorine. The helium supply unit 41, chlorine supply unit 42, and oxygen supply unit 43 are all electrically connected to the control module 31, which can independently adjust the gas flow rate of each inlet 11 corresponding to the helium supply unit 41, chlorine supply unit 42, and oxygen supply unit 43. Helium is the first gas, serving as both a carrier gas and a protective gas; chlorine is the second gas, used for the dehydroxylation of the quartz powder rod; and oxygen is the third gas, used to assist in the sintering of the quartz powder rod, and can also work synergistically with chlorine to achieve dehydration and dehydroxylation. Along the furnace core tube 1 from bottom to top, the helium flow rate at each inlet 11 decreases gradually in a gradient and remains constant throughout the sintering process. This distribution method, with a large helium flow rate at the bottom and a small flow rate at the top, utilizes the excellent thermal conductivity and density characteristics of helium to help suppress the hot gas rising effect and stabilize the longitudinal temperature field distribution. Along the furnace core tube 1 from bottom to top, the initial oxygen and chlorine flow rates at each inlet 11 also decrease gradually in a gradient. Furthermore, the control module 31 can adjust the oxygen and chlorine flow rates corresponding to each inlet 11 in real time based on feedback signals from the powder temperature detector 322 and the online detector 15 during the sintering process. By dynamically adjusting the oxygen and chlorine flow rates at inlets 11 at different heights, the process atmosphere of each section can be precisely matched with the sintering temperature and powder shrinkage state of the corresponding section, achieving refined zone control and effectively reducing the hydroxyl content gradient along the longitudinal direction of the product. The PLC incorporates a closed-loop component control program, using uniform exhaust component concentration across the entire longitudinal region as the control benchmark. It maintains a constant helium supply flow rate across five channels, adjusting only the oxygen and chlorine intake rates in designated zones. When the component concentration in a zone deviates from the benchmark range, the corresponding intake parameters are corrected immediately. This, combined with temperature control components and separate gas supply components, forms a multi-parameter closed-loop control system. Helium, as the carrier gas, maintains a constant flow rate throughout the process, ensuring stable pressure and flow fields within the pipe and preventing carrier gas fluctuations from interfering with the sintering process. Precise component control is achieved solely through adjustment of reactive gases, balancing flow field stability and component control accuracy.

[0029] In this embodiment, the number of air inlets 11 and exhaust ports 12 on both sides of the furnace core tube 1 is the same, five in each case. The spacing between adjacent air inlets is 300-600mm, and each air inlet 11 and its corresponding exhaust port 12 are arranged opposite each other in the radial direction of the furnace core tube 1. This allows the process gas to enter the furnace core tube 1 through the air inlet 11, pass laterally through the tube cavity and directly wash the surface of the powder rod, and then exit from the exhaust port 12 on the opposite side, forming a radially penetrating atmosphere flow path. This avoids the problem of vertical atmosphere stratification caused by vertical straight-through airflow. Each zone corresponds to an independent exhaust channel, and the crosstalk between zones is extremely low. Compared with the traditional vertical arrangement of process gas flowing vertically from bottom to top in vertical equipment, the radially opposite arrangement adopted in this application can significantly shorten the residence time of process gas in the tube, allowing fresh gas to reach the surface of the powder rod more efficiently to participate in the reaction. At the same time, reaction by-products can be quickly carried out and discharged, avoiding the problem of decreased hydroxyl removal efficiency caused by the accumulation of by-products along the process in the vertical flow mode, and further optimizing the dehydroxylation and sintering effect of each section of the powder rod.

[0030] Existing sintering processes generally adopt a passive operation mode with multiple gas synchronous linkage ratios and fixed gas supply flux. The furnace body is not equipped with a zoned in-situ online hydroxyl detection structure, making it impossible to monitor the concentration of hydroxyl, chlorine, and oxygen components in the exhaust gas of powder in each sintering zone in real time. Traditional processes use helium, oxygen, and chlorine gas with synchronous gradient variable flow rates, which cannot separate and control the carrier gas and reactant gas. It is difficult to balance the longitudinal exhaust gas component concentration under the premise of stabilizing the flow field inside the pipe. The production process relies on a post-feedback control mode of "sintered finished product → offline detection of slices → reverse manual adjustment of atmosphere and temperature parameters". The parameter adjustment has a strong lag and a long debugging cycle. It is impossible to actively control the flux of oxidizing and dehydroxylating active gases in different zones during the sintering operation, and it is difficult to simultaneously optimize the consistency of atmosphere components throughout the entire area. The yield rate of ultra-long quartz powder rods is low, and the mass production capacity of adapting to high-end customized low-hydroxyl quartz masterbatch is insufficient.

[0031] In view of the above problems, this application also discloses a sintering method for synthesizing quartz powder rods, which is carried out using the above-mentioned apparatus and includes the following steps: S1. The vertically mounted quartz powder rod 5 is vertically clamped and fixed on the output shaft of the rotary drive component 22 in the vertical rod feeding mechanism 2, so that the quartz powder rod 5 is located inside the furnace core tube 1. After sealing the tube, the quartz powder rod 5 is preheated by the segmented independent temperature control component 3. At the same time, the initial gas flow rate of each gas supply component 4 is distributed according to the decreasing flow rate of each gas inlet 11 from bottom to top. Based on the length, diameter, weight, and bulk density of the powder rod, the total flow rate of He, O2, and Cl2 process gases is calculated, and the overall gas ratio concentration is determined. The helium ratio parameters of the five gas inlets 11 are preset, numbered 1 to 5 from bottom to top. The helium flow rate is distributed differentially according to the maximum flow rate at inlet 1 and decreasing gradually upwards. The five helium channels from bottom to top are numbered 1 to 5. The flow rate as a percentage of the total helium flow rate is as follows: No. 1 25%–32%, No. 2 20%–25%, No. 3 18%–22%, No. 4 15%–20%, and No. 5 10%–15%, following a progressively decreasing pattern of No. 1 > No. 2 > No. 3 > No. 4 > No. 5. The total percentage of the five inlets is 100%, meaning that the initial flow rate of inlets 11 from bottom to top is set according to a gradient decreasing ratio. After the parameters are set, the helium inlet flow rate of the five inlets remains constant throughout the sintering process. The initial gradient inlet flow rates of oxygen and chlorine are preset simultaneously, and the initial distribution ratio of oxygen and chlorine is consistent with the helium gradient. The flow rate of inlet 1 is relatively large and decreases progressively upwards. The initial proportion of gas components in each inlet is consistent. The oxygen and chlorine can be dynamically adjusted independently by zone based on real-time detection data. The gas supply control rule is that the helium gas from the bottom to the top of the No. 1 to No. 5 inlet 11 is pre-distributed according to the gradient difference ratio. The flow rate is locked constant throughout the operation and no dynamic adjustment is made. This is used to stabilize the overall flow field and pressure in the pipe. Oxygen and chlorine gas are only initially distributed according to the gradient decrease from bottom to top. They are not limited by a fixed ratio during the sintering process. The PLC combines the measured data of the exhaust gas components in the zone to independently fine-tune the gas intake of the corresponding numbered inlet 11, balance the longitudinal gas consumption and reaction differences, and ensure the uniform concentration of longitudinal exhaust components in the pipe.

[0032] The vertical feeding mechanism 2 drives the quartz powder rod 5 to rotate and reciprocate along the axis of the furnace core tube 1 throughout the subsequent sintering process. By adjusting the parameters of the vertical feeding mechanism 2, the rotation speed of the powder rod is set to 1-20 r / min, the vertical reciprocating speed is set to 0-20 mm / min, and the vertical reciprocating stroke is set to be no less than the outer distance of the adjacent temperature control module 32 to weaken the influence of the heating blind zone and pre-verify the stability of the rotation and lifting operation. From the start of the process to the completion of sintering, the powder rod maintains the state of rotation and vertical reciprocating movement throughout the process.

[0033] S2. The segmented independent temperature control component 3 maintains the tube in a low-temperature range. The first and third gases are introduced through each air inlet 11 to preheat, dehydrate, and initially remove impurities from the quartz powder rod 5. This stage is the low-temperature pretreatment stage. The segmented independent temperature control component 3 presets a reference temperature of 950-1250℃. The powder temperature detector 322 uploads the powder temperature of each segment in real time. The PLC adjusts the power of each heating unit 321 to alleviate the thermal rise temperature difference and maintain constant temperature sintering of the powder throughout the entire range. The vertical rod feeding mechanism 2 drives the powder rod to continuously move across the heating unit. The 321-cell gap reduces the impact of heating blind spots, improves unilateral heating through rotation, and optimizes the radial temperature uniformity of the powder. A mixture of helium and oxygen is introduced to preheat and dehydrate the powder and remove impurities. After pretreatment, the oxygen supply is cut off, leaving only a constant supply of helium from five channels. The powder is kept at constant temperature and pressure for 120-300 minutes to complete deep exhaust and impurity removal. The constant temperature online detector 15 collects real-time data on the exhaust gas composition of each zone, and the PLC adjusts the oxygen intake at the corresponding air inlet 11 to ensure consistent longitudinal exhaust component concentration.

[0034] S3. The tube is heated to the medium temperature range by the segmented independent temperature control component 3. The first gas, the second gas and the third gas are introduced through each air inlet 11 to perform slow shrinkage and hydroxyl control treatment on the quartz powder rod 5 after preheating, dehydration and preliminary impurity removal. This stage is the slow shrinkage and hydroxyl control stage of powder: After the low temperature pretreatment is completed, the furnace core tube 1 is heated to 1150-1300℃ at a heating rate of 1-2℃ / min and enters the slow shrinkage and hydroxyl control process. The total duration of this stage is not less than 60 minutes. It can be operated by constant temperature after heating or continuous slow heating. During the phase, the five helium gas supply channels maintain a constant flow rate. The chlorine and oxygen intake rates are controlled by the PLC in conjunction with the hydroxyl concentration data detected in real time by the FTIR at the exhaust end. When the hydroxyl detection value at the exhaust end approaches the 5%-10% deviation range of the preset product hydroxyl target value, the PLC gradually and slowly reduces the chlorine intake flow rate at each inlet to control the dehydroxylation reaction rate, so that the hydroxyl index inside the product gradually approaches the target value, avoiding longitudinal hydroxyl gradient deviation caused by excessively fast dehydroxylation rate.

[0035] S4. The tube is heated to a high temperature range by segmented independent temperature control components 3. The first and third gases are introduced through each air inlet 11 to sinter and shape the quartz powder rod 5 after slow shrinkage and hydroxyl control treatment, thus completing the sintering of the quartz powder rod 5. This stage is the high-temperature sintering stage: After the slow shrinkage and hydroxyl control process is completed, the furnace core tube 1 is heated to the sintering reference temperature of 1450-1550℃ at a heating rate of 1-6℃ / min. The temperature control components continuously maintain constant temperature control, the chlorine gas supply is turned off, and only the helium and oxygen binary gas supply is retained. The five helium gas supply channels maintain a constant preset flow rate. The rod feeding mechanism maintains its rotation and lifting. Continuous operation weakens heating blind spots and optimizes radial heating conditions; the online detector in 15 zones collects the concentration of hydroxyl and oxygen components in the exhaust gas in real time throughout the sintering process, and the PLC compares the baseline values ​​of the components in the whole area. The oxygen intake of the corresponding air inlet 11 is dynamically adjusted in each zone to correct the longitudinal component deviation and ensure that the longitudinal exhaust component concentration in the pipe is highly consistent. A closed-loop control system of "powder temperature measurement and constant temperature - helium constant flow and stable field - oxygen and chlorine dynamic adjustment - in-situ component monitoring" is constructed. The hydroxyl deviation is actively optimized in the sintering process, which improves the traditional offline post-sintering parameter adjustment operation mode and enhances the uniformity of longitudinal and radial hydroxyl distribution of the powder rod.

[0036] This embodiment includes three independent process stages: low-temperature pretreatment, slow shrinkage and hydroxyl control stage of powder, and high-temperature sintering. The helium gradient ratio is kept constant throughout the process, while the oxygen and chlorine are dynamically adjusted based on the initial gradient. The specific gas mixing criteria are as follows: Low-temperature pretreatment stage (950-1250℃) baseline ratio: He and O2 mixed gas is introduced for powder preheating treatment; process limitation in this stage: the total amount of oxygen introduced accounts for 10%-15% of the total amount of He and O2 gas introduced; the initial flow rate of inlets 1 to 5 is set from bottom to top according to the gradient ratio, and the oxygen intake of the corresponding numbered inlets is dynamically fine-tuned according to the waste gas component detection data of the sintering process to ensure the consistency of the vertical component concentration.

[0037] The standard ratio for the slow shrinkage and hydroxyl control stage of powder (1150-1300℃) is as follows: maintain the three-way gas supply mode of He, O2, and Cl2. The process is limited in this stage: the total amount of oxygen introduced accounts for 10%-30% of the total amount of He, O2, and Cl2 introduced, and the total amount of chlorine introduced accounts for 7%-20% of the total amount of He, O2, and Cl2 introduced. Helium is still supplied through inlets 1 to 5 in the above decreasing gradient ratio. Oxygen and chlorine use the initial gradient and are controlled in a closed loop based on the FTIR hydroxyl detection data at the exhaust end. When the hydroxyl detection value at the exhaust end approaches the 5%-10% deviation range of the preset target value of hydroxyl in the product, the PLC slowly reduces the chlorine inlet flow rate of each channel to smoothly control the dehydroxylation rate and avoid the hydroxyl gradient difference inside the powder.

[0038] The standard ratio for the high-temperature sintering stage (1450-1550℃) is as follows: chlorine supply is turned off, and only He and O2 binary protective sintering gases are introduced. The process is limited in this stage: the total amount of oxygen introduced accounts for 3%-10% of the total amount of He and O2 binary gases introduced. The helium gas at inlets 1 to 5 is still supplied at a constant gradient ratio as described above. The oxygen is based on the above gradient as the initial reference. During the sintering process, the oxygen intake of the corresponding numbered inlets is dynamically adjusted according to the waste gas component detection data of each zone to adapt to the high-temperature dense sintering conditions.

[0039] This application's furnace core tube adopts a transverse cross-flow airflow structure with longitudinally spaced lateral air intake on the right side and parallel lateral exhaust at corresponding positions on the left side. Helium is pre-set with gradient-differentiated proportions at the five air inlets, ensuring a constant helium intake throughout the sintering process, thus stabilizing the overall flow field and pressure within the tube. Only oxygen and chlorine are controlled variables, with their throughput adjustable independently in each zone. Independent heating units are arranged longitudinally at equal intervals outside the furnace, with a powder surface temperature detector positioned one-to-one on the side of each unit. The detector directly collects the real-time temperature of the powder surface at the corresponding location. Each heating unit can independently adjust its output power, relying on a PLC-linked closed-loop adjustment of the temperature measurement data to mitigate the longitudinal temperature difference caused by hot gas rising and optimize the uniformity of the longitudinal temperature field. It is also equipped with a zoned exhaust FTIR hydroxyl online detector to collect real-time data on the concentrations of hydroxyl, chlorine, and oxygen components in the exhaust gas from each zone. The PLC combines this data with the measured values ​​of the exhaust gas components. The system features zoned linkage adjustment of oxygen and chlorine intake at corresponding inlets, dynamically correcting intake flow when component concentration exceeds tolerance, ensuring highly uniform longitudinal exhaust component concentration within the furnace core tube. A four-tiered linkage control system is constructed, comprising powder temperature measurement and closed-loop temperature control, helium constant flow, oxygen and chlorine zoned dynamic adjustment, and in-situ online component monitoring. An additional vertical rod feeding mechanism drives the powder rod's rotation and vertical reciprocating movement throughout the sintering process. The vertical reciprocating movement of the powder rod is greater than or equal to the distance between the outer sides of two sets of heaters, weakening the influence of heating blind zones by crossing heating gaps. The powder rod's rotation changes the powder's heating orientation, improving radial heating conditions and optimizing radial temperature uniformity. This enables active control of powder hydroxyl parameters during sintering, improving upon traditional post-sintering offline parameter adjustment. It can control longitudinal hydroxyl fluctuations of ultra-long powder rods to within 1 ppm, longitudinal powder sintering temperature difference to within ±2℃, and radial sintering temperature difference to ≤1℃.

[0040] The following detailed embodiments and comparative examples illustrate this scheme. All embodiments and comparative examples use the same ultra-high purity furnace core tube, and the substrate to be sintered is uniformly a synthetic quartz powder rod with a diameter of 400 mm and a length of 2000 mm, and a powder bulk density of 0.25-0.45 g / cm³. The initial gas gradient ratios of the five gas inlets all fall within the ratio range defined above, with the embodiments using the optimal ratio scheme within this range.

[0041] Example 1: In this embodiment, the vertical feeding mechanism drives the quartz powder rod to rotate at a speed of 5 r / min throughout the entire process, with a vertical reciprocating speed of 10 mm / min and a travel distance of 550 mm, which is greater than the distance between the outer sides of adjacent heating units.

[0042] During the cryogenic pretreatment stage, the baseline temperature was 1100℃, and the pretreatment time was 180 min. The total helium supply flow rate was constant at 50.0 L / min (standard conditions), with five helium inlets using a fixed gradient flow rate (constant throughout). The inlets, from bottom to top, were 1-5: Inlet 1 14.0 L / min, Inlet 2 11.2 L / min, Inlet 3 10.0 L / min, Inlet 4 8.8 L / min, and Inlet 5 6.0 L / min, for a total precise helium flow rate of 50.0 L / min. A binary mixture of He and O2 was introduced during this stage, with a total binary gas flow rate of 57.5 L / min. L / min, meeting the proportion requirements for this stage: oxygen accounts for 13.0% of the total binary gas volume, falling within the 10%-15% range; total oxygen flow rate is 7.5L / min, and oxygen is distributed along the same source gradient as helium with single-channel gas flow rates: oxygen single-channel flow rates: No. 1 2.1L / min, No. 2 1.7L / min, No. 3 1.5L / min, No. 4 1.3L / min, No. 5 0.9L / min; during sintering, the PLC dynamically fine-tunes the oxygen single-port flow rate based on the partition exhaust gas component detection data to ensure consistent vertical component concentration; after pretreatment, the oxygen supply is cut off, and only five constant helium channels are retained, and the system is kept at constant temperature and pressure for 200min.

[0043] During the slow shrinkage and hydroxyl control stage of the powder, the heating rate was 1.5℃ / min, reaching 1220℃, and held at that temperature for 100min, for a total stage duration of 150min. Five helium gas supply lines maintained their original constant flow rates: Line 1 14.0L / min, Line 2 11.2L / min, Line 3 10.0L / min, Line 4 8.8L / min, and Line 5 6.0L / min. The five supply lines maintained a fixed gradient percentage: Line 1 28%, Line 2 22.4%, Line 3 20%, Line 4 20%, Line 5 20%, Line 6 20%, Line 7 20%, Line 8 20%, Line 9 20%, Line 1 ... The percentages of No. 1, No. 4 (17.6%), and No. 5 (12%), when added together to 100%, constitute the uniform gradient value for this application. Oxygen and chlorine are distributed using the same gradient, meaning the percentage ratios of oxygen and chlorine in the five inlets are matched with the fixed, decreasing percentages of helium (No. 1 to No. 5). All three process gases (helium, oxygen, and chlorine) are distributed to their respective inlets using the same decreasing percentage ratio. A three-way ternary gas mixture is introduced in this stage, with a total intake of 70%. 0.0 L / min, meeting the mixing ratio requirements for this stage: oxygen accounts for 20.0% (10%-30%) of the total ternary gas volume, and chlorine accounts for 8.6% (7%-20%) of the total ternary gas volume; the initial total flow rate of oxygen is 14.0 L / min, and the initial total flow rate of chlorine is 6.0 L / min. For the same gradient, single-channel oxygen flow rates are: No. 1 3.9 L / min, No. 2 3.1 L / min, No. 3 2.8 L / min, No. 4 2.5 L / min, and No. 5 1.7 L / min. n; Single-channel chlorine gas flow rate of the same gradient: No. 1 1.7L / min, No. 2 1.3L / min, No. 3 1.2L / min, No. 4 1.1L / min, No. 5 0.7L / min; When the measured value of hydroxyl at the exhaust end approaches the target value within the 7% deviation range, the PLC uniformly reduces the chlorine gas inlet flow rate of each channel, and the total chlorine gas flow rate drops to 0.1L / min at the end of the stage, so as to smoothly control the dehydroxylation reaction rate; The oxygen flux is dynamically fine-tuned by the PLC in combination with the exhaust gas composition data.

[0044] During the high-temperature sintering stage, the heating rate was 3.5℃ / min, and the temperature was raised to 1500℃ for constant sintering for 240 minutes. Chlorine gas supply was shut off throughout the process, while the flow rates of the five helium inlets remained constant: inlet 1 14.0 L / min, inlet 2 11.2 L / min, inlet 3 10.0 L / min, inlet 4 8.8 L / min, and inlet 5 6.0 L / min. He and O2 binary gases were introduced during this stage, with a maximum total binary gas flow rate of 55.0 L / min. L / min, meeting the mixing ratio requirements for this stage: oxygen accounts for 9.1% (3%-10%) of the total binary gas volume; initial total oxygen flow rate is 5.0 L / min, and the oxygen flow rates of single channels in the same source gradient are: No. 1 1.4 L / min, No. 2 1.1 L / min, No. 3 1.0 L / min, No. 4 0.9 L / min, and No. 5 0.6 L / min; during the sintering process, the PLC dynamically fine-tunes the oxygen flux of the corresponding numbered inlet based on the detection data of the waste gas components in the zone, adapting to the high-temperature and dense sintering conditions.

[0045] After the sintered product is sintered, the ends with varying diameters are removed, leaving the effective length in the middle. A strip sample with a length of 900 mm and a thickness of 30 mm is cut along the axial center. After polishing and grinding the upper and lower surfaces, Raman spectroscopy is performed from one end to the other along the length. Data is collected at the center position and 80 mm away from the center, and the distribution curve of hydroxyl content along the length is plotted. The test results show that the longitudinal hydroxyl fluctuation values ​​at the two detection positions are 0.93 ppm and 0.98 ppm, respectively, and the hydroxyl difference of the whole rod is controlled within 1 ppm.

[0046] Comparative Example 1: This comparative example uses a traditional single-port, top-to-bottom through-air-inlet sintering furnace with a single-port air inlet at the bottom of the glass tube and a single-port air outlet at the top. It does not have segmented temperature control, zoned FTIR detection, or dynamic oxygen-chlorine regulation functions. All other process parameters are consistent with those in Example 1.

[0047] The sintered product was tested, and the longitudinal hydroxyl fluctuations at the two test locations were 23.48 ppm and 24.52 ppm, respectively, with the hydroxyl difference for the whole rod exceeding 1 ppm.

[0048] Reference Figure 5 Comparing the data from Example 1 and Comparative Example 1, Example 1 exhibits stronger controllability of hydroxyl concentration, with more uniform and stable fluctuations. Comparative Example 1 suffers from large hydroxyl fluctuations, characterized by severe hydroxyl drift from one end to the other, making accurate control of hydroxyl concentration impossible. Example 1 demonstrates a clear advantage. Therefore, compared to traditional single-port through-flow sintering furnaces with integrated temperature control, this application, through lateral gas inlet and outlet arrangement, constant flow and stable field of helium gas with the same gradient throughout the process, blind zone elimination via full-domain rotation and lifting of the powder rod, three-stage graded hydroxyl control, hydroxyl prediction and slow reduction of chlorine flow, and zoned oxygen and chlorine independent closed-loop regulation, can effectively compress the longitudinal and radial sintering temperature difference of the powder rod, significantly reduce the amplitude of hydroxyl fluctuations across the entire domain, adapt to low-hydroxyl homogeneous sintering of ultra-long quartz powder rods, significantly improve the yield of mass production, and solve the problems of uneven heating, large atmosphere gradient, and lagging hydroxyl control in traditional processes.

[0049] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0050] It should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0052] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A sintering apparatus for synthesizing quartz powder rods, characterized in that, The furnace core tube (1), vertical rod feeding mechanism (2), and segmented independent temperature control assembly (3) are included. Multiple air inlets (11) and exhaust ports (12) are respectively provided on both sides of the furnace core tube (1). Each air inlet (11) is connected to an independently controlled gas supply assembly (4). The gas supply assembly (4) is used to provide a first gas as a protective gas, a second gas for dehydroxylation of quartz powder rods, and a third gas to aid sintering. The gas supply assembly (4) includes a helium gas supply unit (41), a chlorine gas supply unit (42), and an oxygen gas supply unit (43). Along the furnace core tube (1) from bottom to top, the helium gas inlet flow rate of each air inlet (11) decreases gradually according to the gradient and remains constant throughout the sintering process. Along the furnace core tube (1) from bottom to top, the initial oxygen gas inlet flow rate and the initial chlorine gas inlet flow rate of each air inlet (11) decrease gradually according to the gradient. The segmented independent temperature control component (3) includes a control module (31) and multiple temperature control modules (32). The multiple temperature control modules (32) are arranged at intervals along the axial direction of the furnace core tube (1) and are all electrically connected to the control module (31). The interval between two adjacent temperature control modules (32) forms a heating gap. The vertical rod feeding mechanism (2) includes a linear drive (21) and a rotary drive (22). The linear drive (21) is connected to an external carrier, and the rotary drive (22) is located at the output end of the linear drive (21). The quartz powder rod (5) is connected to the output end of the rotary drive (22) and is located on the same axis as the furnace core tube (1). The rotary drive (22) is used to drive the quartz powder rod (5) to rotate around its own axis. The linear drive (21) is used to drive the rotary drive (22) and the quartz powder rod (5) to move back and forth along the axial direction of the furnace core tube (1). The maximum displacement distance of the quartz powder rod (5) is not less than the length of the heating gap.

2. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, The furnace core tube (1) is an infrared transparent quartz glass tube with a hydroxyl content of no more than 1 ppm, and the inner wall of the furnace core tube (1) is coated with a high-temperature resistant alumina infrared light-transmitting protective coating.

3. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, Each of the multiple air inlets (11) is provided with a pressure stabilizing channel (13), and each of the two ends of the pressure stabilizing channel (13) is provided with a number of breathable micro-holes (131) around the center.

4. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, Each of the exhaust ports (12) is fixedly connected to a quartz cylindrical window (14), the hydroxyl content of the quartz cylindrical window (14) is not greater than 0.5 ppm, and an online detector (15) is provided on the quartz cylindrical window (14). The online detector (15) is electrically connected to the control module (31) and is used to perform in-situ online detection of exhaust components.

5. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, The temperature control module (32) includes a heating unit (321) and a powder temperature detector (322). The heating unit (321) and the powder temperature detector (322) are both fixedly connected to the furnace core tube (1) and electrically connected to the control module (31). The powder temperature detector (322) is arranged perpendicular to the outer wall of the quartz powder rod (5) and is used to collect the sintering temperature of the powder surface at the corresponding position and feed the temperature data back to the control module (31). The control module (31) independently adjusts the output power of the corresponding heating unit (321) according to the measured temperature of each powder temperature detector (322).

6. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, The helium supply unit (41), the chlorine supply unit (42), and the oxygen supply unit (43) are all electrically connected to the control module (31). The control module (31) is used to independently adjust the gas supply flow of the helium supply unit (41), chlorine supply unit (42), and oxygen supply unit (43) corresponding to each of the gas inlets (11).

7. The sintering apparatus for synthesizing quartz powder rods as described in claim 6, characterized in that, The control module (31) can adjust the oxygen and chlorine flow rates corresponding to each of the air inlets (11) during the sintering process.

8. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, The linear drive (21) drives the quartz powder rod (5) to reciprocate along the axis of the furnace core tube (1) at a speed of 0 to 20 mm / min; the rotary drive (22) drives the quartz powder rod (5) to rotate at a speed of 1 r / min to 20 r / min.

9. The sintering apparatus for synthesizing quartz powder rods as described in claim 1, characterized in that, The number of air inlets (11) and exhaust ports (12) is the same, and each air inlet (11) and a corresponding exhaust port (12) are arranged opposite to each other in the radial direction of the furnace core tube (1).

10. A method for sintering synthetic quartz powder rods, comprising using the sintering apparatus as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Install the quartz powder rod (5) at the output end of the vertical rod feeding mechanism (2) so that the quartz powder rod (5) is located inside the furnace core tube (1). After sealing the tube, the quartz powder rod (5) is preheated by the segmented independent temperature control component (3). At the same time, the initial gas flow of each gas supply component (4) is distributed in a manner that the flow rate of each gas inlet (11) decreases from bottom to top. The vertical rod feeding mechanism (2) drives the quartz powder rod (5) to rotate and reciprocate along the axis of the furnace core tube (1) throughout the subsequent sintering process. S2. The tube is kept in a low temperature range by segmented independent temperature control components (3), and the first gas and the third gas are introduced through each air inlet (11) to preheat, dehydrate and initially remove impurities from the quartz powder rod (5). S3. The tube is heated to the medium temperature range by segmented independent temperature control components (3), and the first gas, the second gas and the third gas are introduced through each air inlet (11) to perform slow shrinkage and hydroxyl control treatment on the quartz powder rod (5) after preheating, dehydration and preliminary impurity removal. S4. The tube is heated to a high temperature range by segmented independent temperature control components (3), and the first gas and the third gas are introduced through each air inlet (11) to sinter and shape the quartz powder rod (5) after slow shrinkage and hydroxyl control treatment, thus completing the sintering of the quartz powder rod (5).

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