A method for producing a brown quartz glass tube

Abstract

The application discloses a production method of brown quartz glass tubes and belongs to the technical field of quartz glass preparation. Raw material components are as follows in percentage by mass: quartz sand 96.5%, samarium oxide 2.8%, and aluminum powder 0.7%. The aluminum powder is added into 31 DEG C hydrochloric acid and diluted, and then is uniformly mixed and stirred with the samarium oxide and the quartz sand. The mixture is dried at 980 DEG C for 8 min. After being cooled to below 50 DEG C, the mixture is put into a continuous melting furnace and is melted at 1900 DEG C. The brown quartz glass tube is obtained through traction drawing. The process parameters are accurately controllable, the production stability is high, the continuous melting furnace equipment is effectively protected, the stable and uniform doping of the coloring components is ensured, the prepared quartz tube is uniform in color, has no obvious color spot defects, and is stable in structure, and the finished product has the effects of high-temperature resistance and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of quartz glass preparation technology, and in particular to a method for producing brown quartz glass tubes. Background Technology

[0002] Quartz glass is widely used in infrared heating lamps due to its high temperature resistance, low coefficient of thermal expansion, and excellent light transmittance. Most existing brown quartz glass is colored using iron and chromium oxides, but some processes suffer from uneven coloring, easy precipitation at high temperatures, and uneven mixing of raw materials.

[0003] In the traditional process of drying mixed materials, low-temperature operation can only achieve simple dehydration. If the temperature is not up to standard, it will easily lead to insufficient samarium oxide doping or hydrochloric acid residue, which will cause corrosion and damage to the continuous melting furnace.

[0004] During normal temperature operation, uneven coloring of products is likely to occur, resulting in large color differences between different batches, unstable production, and inability to achieve continuous production operation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for producing brown quartz glass tubes. This method features a simple and controllable process, resulting in uniform brown color in the quartz glass tubes. By setting a high-temperature, short-time drying operation, it ensures complete evaporation of hydrochloric acid, protecting the continuous melting furnace equipment. The method also exhibits good stability during high-temperature use, with no obvious color spots or bubble defects, thus solving the problems mentioned in the background technology.

[0006] This invention provides the following technical solution: a method for producing brown quartz glass tubes, comprising the following steps: S1. Raw material selection: Raw materials by mass percentage: quartz sand 96.5%, samarium oxide 2.8%, aluminum powder 0.7%; quartz sand for pipe drawing SiO2 ≥ 99.6%; aluminum powder particle size 30-80 mesh; samarium oxide purity ≥ 99.8%; S2. Aluminum powder dilution pretreatment: Dilute the aluminum powder in hydrochloric acid at 31℃; S3. Mixing and stirring: Add the diluted aluminum powder, samarium oxide and quartz sand into the mixer and stir evenly to obtain a mixture; S4. Drying Treatment: The mixture is fed into a drying oven and dried at 980℃ for 8 minutes. This step uses a high-temperature short-time drying process of 980℃ for 8 minutes, which has been determined through extensive and repeated experiments. Temperatures above 980℃ will cause samarium oxide to volatilize and be lost, resulting in insufficient samarium oxide content in the glass system and failing to meet design requirements for coloring. Temperatures below 980℃ and time below 8 minutes will result in incomplete removal of hydrochloric acid, with residual hydrochloric acid entering the subsequent continuous melting furnace, corroding the furnace body and damaging the equipment. Therefore, a process balance must be maintained between completely removing residual hydrochloric acid and inhibiting samarium oxide volatilization.

[0007] S5. Melting: After drying, the mixture is cooled to below 50°C and put into a continuous melting furnace, where it is heated to 1900°C until it is completely melted. S6. Drawing and forming: A traction machine is used to draw the brown quartz glass tube to the corresponding specifications and dimensions.

[0008] Preferably, the hydrochloric acid in step 2 is dilute hydrochloric acid.

[0009] Preferably, the drawn quartz tube also includes an annealing step to eliminate thermal stress in the tube body.

[0010] Preferably, after annealing, the quartz tube is cut to a fixed length and the inner and outer surfaces are cleaned to obtain the finished quartz glass tube.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. The aluminum powder and hydrochloric acid pretreatment combined with the samarium oxide composite coloring system results in uniform coloring and no obvious color spots or streaks on the surface of the quartz tube; 2. The process is simple, the raw materials are readily available, and the continuous melting and drawing process is suitable for large-scale industrial production; 3. The resulting brown quartz glass tube has a high hydroxyl content and excellent absorption performance in the infrared band, making it suitable for infrared heating lamps; 4. The product has low thermal stress, is not easy to crack during cutting and processing, and is not easy to fade and is corrosion resistant during long-term use at high temperatures. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the production process of the brown glass tube of the present invention; Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Example 1: A method for producing brown quartz glass tubes: 1. Raw material ratio (mass percentage): quartz sand 96.5%, samarium oxide 2.8%, aluminum powder 0.7%; quartz sand SiO2≥99.6%, aluminum powder particle size 30~80 mesh, samarium oxide purity 99.8%.

[0015] 2. Pre-treat the aluminum powder by diluting it in 31℃ dilute hydrochloric acid.

[0016] 3. Add the pretreated aluminum powder, samarium oxide, and quartz sand into the mixer and mix thoroughly.

[0017] 4. Place the mixture into a drying oven and dry at 980℃ for 8 minutes.

[0018] 5. Cool the mixture to 45°C, put it into a continuous melting furnace, and heat it to 1900°C to melt it.

[0019] 6. The traction machine draws the material to obtain a brown quartz glass tube; the tube is then sent to an annealing furnace to relieve stress, and after cooling, it is cut and cleaned to obtain the finished product.

[0020] Excessive temperature / time in step 4 can cause samarium oxide to volatilize, reducing the effective doping amount; insufficient temperature / time will prevent hydrochloric acid from fully volatilizing, and residual hydrochloric acid will corrode subsequent continuous melting furnace equipment. This process achieves complete removal of residual hydrochloric acid while controlling samarium oxide volatilization, improving the overall coloring effect of the quartz tube and enhancing production stability and safety.

[0021] The finished quartz tube in this embodiment has a uniform brown color, a high hydroxyl content, and is free of bubbles and spots. It does not fade significantly after being kept at 1000℃ for 200 hours, meeting the requirements for use as an infrared heating lamp tube.

Claims

1. A method for producing a brown quartz glass tube, characterized in that: Includes the following steps: S1. Raw material selection: Raw materials by mass percentage: quartz sand 96.5%, samarium oxide 2.8%, aluminum powder 0.7%; quartz sand for pipe drawing SiO2 ≥ 99.6%; aluminum powder particle size 30-80 mesh; samarium oxide purity ≥ 99.8%; S2. Aluminum powder dilution pretreatment: Dilute the aluminum powder in hydrochloric acid at 31℃; S3. Mixing and stirring: Add the diluted aluminum powder, samarium oxide and quartz sand into the mixer and stir evenly to obtain a mixture; S4. Drying treatment: The mixture is fed into a drying oven and dried at 980℃ for 8 minutes. S5. Melting: After drying, the mixture is cooled to below 50°C and put into a continuous melting furnace. The temperature is raised to 1900°C until it is completely melted. S6. Drawing and forming: A traction machine is used to draw the brown quartz glass tube to the corresponding specifications and dimensions.

2. The method for producing a brown quartz glass tube according to claim 1, characterized in that: The hydrochloric acid mentioned in step S2 is dilute hydrochloric acid.

3. The method for producing a brown quartz glass tube according to claim 1, characterized in that: The drawn quartz tube also undergoes an annealing process to eliminate thermal stress in the tube.

4. The method for producing a brown quartz glass tube according to claim 1, characterized in that: After annealing, the quartz tube is cut to a fixed length and the inner and outer surfaces are cleaned to obtain the finished quartz glass tube.

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