High-purity tellurium production process

Abstract

The invention relates to the technical field of purification, and discloses a high-purity tellurium production process which comprises the following steps: 1, distilling and purifying; step 2, secondary distillation and purification; step 3, collecting a distillation product; step 4, zone-melting purification; step 4, zone-melting purification; step 6, secondary zone-melting purification; and step 7, forming and packaging. According to the production process of the high-purity tellurium, the 4N tellurium raw material is deeply processed in a secondary distillation purification and secondary zone-melting purification mode, so that a high-purity tellurium product with higher purity and better quality is obtained, the loss of the raw material is reduced in the production process, the yield of the product is improved, and the low-purity tellurium raw material can be directly improved to higher purity; the production efficiency of the purification operation is improved, and meanwhile, the head and tail materials are recycled and redistilled in the two zone-melting purification operation processes, so that the head and tail materials of tellurium products generated in each round can be put into the next purification process again, and the production quality and efficiency of the products are ensured while the waste of tellurium raw materials is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of purification, and particularly to a high-purity tellurium production process. Background Art

[0002] High-purity tellurium is an important semiconductor material with excellent optoelectronic properties and thermal stability, and is widely used in fields such as solar cells, infrared detectors, and lasers. Since very trace amounts of impurities can also cause the electrical properties of the material to deteriorate, the purity of tellurium is an important factor directly affecting the material properties.

[0003] In the prior art, the purification and processing of tellurium materials generally adopt chemical methods and physical methods. The chemical method separates tellurium from impurities through oxidation and reduction chemical reactions, and this method has strong flexibility and large selectivity. The physical method uses methods such as evaporation, solidification, crystallization, and diffusion to remove impurities through physical processes, and mostly adopts a physical purification process composed of multiple vacuum distillations and zone melting to prepare high-purity tellurium.

[0004] However, the physical method in the prior art generally can only purify tellurium products of one grade. For example, 5N tellurium is produced by purifying 4N tellurium, or 6N tellurium is produced using 5N tellurium. On the premise of a complex purification process, a large amount of resources will be wasted, affecting the yield of high-purity tellurium. In view of this, we have proposed a high-purity tellurium production process. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-purity tellurium production process to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A high-purity tellurium production process, including the following steps: Step 1, distillation purification: Take industrial 4N tellurium raw materials and place them in a distillation pot for distillation operations, and hermetically collect the volatiles generated during distillation; Step 2, secondary distillation purification: Perform secondary distillation on the distillation bottom material in the distillation pot in Step 1, and at the same time hermetically collect the volatiles generated during this process; Step 3, collect distillation products: Collect the distillation products obtained in Step 1 and Step 2 to obtain a distillation 5N tellurium product; Step 4, zone melting purification: Make the distillation 5N tellurium product obtained in Step 3 into a rod shape, and place it in a zone melting furnace for zone melting purification, and hermetically collect the volatiles generated in the zone melting furnace; Step 5, separate the head and tail materials from the zone melting 6N tellurium product: After the zone melting purification in Step 4 is completed, separate and collect the head and tail materials of the rod-shaped distillation 5N tellurium product, and finally obtain a zone melting purified 6N tellurium product; Step 6: Secondary zone melting purification. Place the 6N tellurium product obtained by zone melting purification separated in Step 5 into a zone melting furnace for secondary zone melting purification operation. After the secondary zone melting purification operation, separate and collect the head material and tail material of the product, and finally obtain 7N tellurium finished product; Step 7: Shaping and packaging. Perform shaping and packaging on the 7N tellurium finished product obtained in Step 6, and finally obtain 7N tellurium product.

[0007] Preferably, the volatile substances generated in Step 1, Step 2, and Step 4 are all collected with a collection tank by using pipelines and exhaust equipment, and the connecting parts between the pipelines, the collection tank, the distillation pot, and the zone melting furnace are all sealed with a heat-insulating and sealing structure. The volatile substances stored in the collection tank are uniformly transported to relevant recycling enterprises for harmless treatment, thereby reducing the emission of harmful substances and reducing the pollution emission during the production operation of high-purity tellurium.

[0008] Preferably, the distillation pots used in Step 1 and Step 2 are different, and the bottom material in the distillation pot in Step 1 is scraped out by a scraping plate to ensure that the residues in the distillation pot are taken out more completely, reducing the waste of material resources. At the same time, in Step 3, the distilled 5N tellurium products obtained in Step 1 and Step 2 are mixed and collected to make the distilled 5N tellurium products more uniform in subsequent processing operations, avoiding impurities concentrating in a certain place and affecting the development of subsequent further purification operations.

[0009] Preferably, before the distillation operations in Step 1 and Step 2, the 4N tellurium raw material and the bottom material of the distillation pot are respectively crushed and preliminarily sieved so that the material size is between 50 - 100 mesh, so that the distillation raw materials can be heated and distilled more quickly in the distillation pot, improving the production efficiency of high-purity tellurium.

[0010] Preferably, the distilled 5N tellurium product obtained in Step 3 is made into a rod shape with a similar overall outer diameter by using a sintering process after sieving and mixing, so as to facilitate the development of subsequent zone melting purification process. And the length of the above-mentioned rod-shaped distilled 5N tellurium product is set between 0.5m - 1.0m, and its diameter is set between 0.15cm - 0.20cm, so as to adapt to the zone melting operation of the zone melting furnace.

[0011] Preferably, the separation positions of the head and tail materials of the tellurium products obtained by zone melting purification separately collected in Step 5 and Step 6 are set at 0.1m - 0.2m from the upper and lower ends of the tellurium products, and the specific position standard for removing the head and tail materials is determined by referring to the color separation on the surface of the tellurium products after zone melting purification, so that the finally zone-melted tellurium products have a higher purity and the impurities are removed more thoroughly.

[0012] Preferably, the head and tail materials of tellurium products collected in the fifth and sixth steps are pre-fed into a crusher for crushing treatment to finally obtain the head and tail materials of block tellurium products. And in the subsequent purification process, the head and tail materials of the obtained block tellurium products are mixed with the crushed 4N tellurium raw materials and sieved together. Finally, the mixture of the two is put into a distillation pot to repeat the work in the first step, so that the head and tail materials of tellurium products generated in each round will be put into the next purification process again, reducing the waste of tellurium raw materials while ensuring the production quality and efficiency of products.

[0013] Preferably, after the tellurium products after the first zone melting purification in the fifth step are cooled to room temperature, the head and tail materials are removed, and then the second zone melting purification is carried out. And after the second zone melting purification operation is completed, it also needs to be cooled to room temperature before removing the head and tail materials and classifying and collecting them, so as to avoid that the tellurium products at too high a temperature directly start the subsequent purification or packaging operations, which will bring extra impurities to the tellurium products and reduce the purity of the tellurium products.

[0014] Preferably, after the distillation purification or zone melting purification in the first, second, and fourth steps is completed and cooled to room temperature, normal temperature air is continuously introduced into the distillation pot and the zone melting furnace to promote the complete discharge and collection of the volatile substances and residual gases in the distillation pot and the zone melting furnace, and then the equipment is opened for the next operation, so as to avoid the residue of distillation volatiles or the escape of harmful gases, which will affect the safety of the production workshop.

[0015] Preferably, when packaging the 7N tellurium finished product in the seventh step, first perform cutting treatment on the 7N tellurium finished product obtained by the second zone melting purification, and process it to about 100 g for each single block of 7N tellurium finished product for packaging, so as to better apply it in the catalyst addition operations of semiconductor devices, alloys, and chemical raw material industrial processing, and improve the application effect of 7N tellurium products.

[0016] Compared with the prior art, the present invention provides a high-purity tellurium production process, which has the following beneficial effects:

[0017] 1. In this high-purity tellurium production process, the 4N tellurium raw materials are deeply processed by the methods of secondary distillation purification and secondary zone melting purification, so as to obtain high-purity tellurium products with higher purity and better quality. During the production process, the raw material loss is reduced, the yield of products is improved, and the tellurium raw materials with low purity can be directly upgraded to a higher purity, thus improving the production efficiency of the purification operation.

[0018] 2. In this high-purity tellurium production process, the head and tail materials are recycled and redistilled during the two zone melting purification operations, so that the head and tail materials of tellurium products generated in each round will be put into the next purification process again, reducing the waste of tellurium raw materials while ensuring the production quality and efficiency of products.

[0019] 3. In the high-purity tellurium production process, volatile substances are collected in a closed manner during the distillation purification and zone melting purification operations. Before the final discharging, harmful gases and volatile substances are discharged by continuously filling the equipment with gas. Then, these harmful gases and volatile substances are transported to relevant enterprises for harmless treatment to ensure the safety of production operations in the production workshop and avoid harm to workers' bodies caused by harmful substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the production process of the present invention; Figure 2 It is a schematic diagram of the production flow of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] As Figure 1 - Figure 2 shown, the present invention provides a technical solution: a high-purity tellurium production process, including the following steps: Step 1. Distillation purification: Take industrial 4N tellurium raw materials and place them in a distillation pot for distillation operation, and collect the volatile substances generated by distillation in a closed manner; Step 2. Secondary distillation purification: Perform secondary distillation on the distillation bottom material in the distillation pot in Step 1, and at the same time collect the volatile substances generated during this process in a closed manner; Step 3. Collect distillation products: Collect the distillation products obtained in Step 1 and Step 2 to obtain a distillation 5N tellurium product; Step 4. Zone melting purification: Make the distillation 5N tellurium product obtained in Step 3 into a rod shape, place it in a zone melting furnace for zone melting purification, and collect the volatile substances generated in the zone melting furnace in a closed manner; Step 5. Separate the head and tail materials from the zone melting 6N tellurium product: After the zone melting purification in Step 4 is completed, separate and collect the head and tail materials of the rod-shaped distillation 5N tellurium product, and finally obtain a zone melting purified 6N tellurium product; Step 6. Secondary zone melting purification: Place the zone melting purified 6N tellurium product separated in Step 5 in a zone melting furnace for secondary zone melting purification operation. After the secondary zone melting purification operation is completed, separate and collect the head material and tail material of the product, and finally obtain a 7N tellurium finished product; Step 7. Shaping and packaging: Perform shaping and packaging on the 7N tellurium finished product obtained in Step 6 to finally obtain a 7N tellurium product.

[0022] In an embodiment of the present invention, the volatiles generated in Step 1, Step 2, and Step 4 are all collected using pipelines and exhaust equipment and a collection tank. Moreover, the connection parts between the pipelines, the collection tank, the distillation pot, and the zone melting furnace are all sealed using a thermal insulation and sealing structure. The volatiles stored in the collection tank are uniformly transported to relevant recycling enterprises for harmless treatment, thereby reducing the emission of harmful substances and the pollution emissions during the production process of high-purity tellurium. Moreover, through purification and reuse in the subsequent production process, these harmful substances can provide other chemical raw materials for industrial production, thus creating more benefits for the entire production process. At the same time, the distillation pots used in Step 1 and Step 2 are different. Moreover, the bottom material in the distillation pot in Step 1 is scraped out using a scraping plate to ensure that the residues in the distillation pot are removed more completely, reducing the waste of material resources. Moreover, the scraping operation is performed using mechanical equipment to avoid direct contact by personnel. At the same time, the distillation pot is cleaned after scraping out the material to reduce the influence of the residues on the subsequent distillation and purification operations. At the same time, in Step 3, the distilled 5N tellurium products obtained in Step 1 and Step 2 are mixed and collected to make the distilled 5N tellurium products more uniform in the subsequent processing operations, avoiding the concentration of impurities in a certain place and affecting the development of the subsequent further purification operations. Moreover, the uniformly mixed tellurium products can participate in the subsequent sintering operation more quickly, thereby improving the production efficiency of the zone melting operation.

[0023] In addition, before the distillation operations in Step 1 and Step 2, the 4N tellurium raw material and the distillation pot bottom material are respectively crushed. This process is operated using a grinding machine to improve the crushing fineness of the 4N tellurium raw material and the distillation pot bottom material, and a preliminary sieving operation is carried out to make the material size between 50 - 100 meshes. The sieved material is crushed again until all reach the above material fineness standard, so that the distillation raw materials can be heated and distilled more quickly in the distillation pot, improving the production efficiency of high-purity tellurium. Further, the distilled 5N tellurium products obtained in Step 3 are made into rods with a similar overall outer diameter using a sintering process after sieving and mixing, thereby facilitating the development of the subsequent zone melting purification process. Moreover, the length of the above-mentioned rod-shaped distilled 5N tellurium products is set between 0.5 m - 1.0 m, and its diameter is set between 0.15 cm - 0.20 cm, so that the size of the tellurium products after processing can not only ensure the development of the zone melting operation but also ensure its reaction efficiency, thus adapting to the development of the zone melting operation of the zone melting furnace.

[0024] In an embodiment of the present invention, the separation position of the head and tail materials of the tellurium product purified by zone melting collected in step 5 and step 6 is set at 0.1m-0.2m at the upper and lower ends of the tellurium product. The specific position standard of removing the head and tail materials is determined by referring to the color separation on the surface of the tellurium product after zone melting purification. The cutting position is within the non-discolored area to avoid excessive impurities, so that the tellurium product finally purified by zone melting has higher purity and impurities are removed more thoroughly. Specifically, the head and tail materials of the tellurium product collected in step 5 and step 6 are pre-put into a crusher for crushing treatment, and finally the head and tail materials of the block tellurium product are obtained, and In the subsequent purification process, the obtained head and tail materials of the block tellurium product are mixed with the crushed 4N tellurium raw material. At this time, a small stirring equipment is used for stirring, and the whole process is carried out in a dry environment. After the stirring is completed, the small stirring equipment is cleaned to reduce the waste of resources and avoid affecting the subsequent purification operation. They are sieved together and finally the mixture of the two is put into the distillation pot to repeat the work of step one, so that the head and tail materials of the tellurium product produced in each round can be put into the next purification process again, reducing the waste of tellurium raw materials while ensuring the production quality and efficiency of the product.

[0025] In the present invention, after the first zone melting purification in step 5, the tellurium product is cooled to room temperature and then the head and tail materials are removed, and then a second zone melting purification is performed. After the second zone melting purification operation is completed, the head and tail materials are also cooled to room temperature and then the head and tail materials are removed and classified and collected, so as to avoid the tellurium product with too high temperature directly starting the subsequent purification or packaging operation, which will bring additional impurities to the tellurium product and reduce the purity of the tellurium product.

[0026] It is worth noting that after the distillation purification or zone melting purification in step 1, step 2 and step 4 is completed and the temperature drops to room temperature, room temperature air continues to be introduced into the distillation pot and the zone melting furnace. The air is preliminarily filtered by the filtering equipment, and then dried by the drying equipment and blown out by the negative pressure fan to avoid humid air or air containing more impurities from entering the distillation pot and the zone melting furnace, which has a negative impact on the production quality of the product, so as to promote the complete discharge and collection of volatiles and residual gases in the distillation pot and the zone melting furnace before opening the equipment for the next operation, thereby avoiding the residual volatiles of the distillation or the residual harmful gases from escaping and affecting the safety of the production workshop. At the same time, when packaging the 7N tellurium product in step 7, the 7N tellurium product obtained by the secondary zone melting purification is first cut and processed into a single block of 7N tellurium product of about 100g for packaging, so as to better apply it to the catalyst addition operation in the industrial processing of semiconductor devices, alloys, and chemical raw materials, and improve the application effect of 7N tellurium products.

[0027] The above has generally described the present invention in detail. However, based on the present invention, some modifications or improvements can be made, which are obvious to those of ordinary skill in the art. Therefore, modifications or improvements made without departing from the spirit and idea of the present invention are within the scope of protection of the present invention.

Claims

1. A high-purity tellurium production process, characterized in that: The following steps are involved: Step 1: Distillation and purification: industrial 4N tellurium raw material is placed in a distillation pot for distillation, and the volatiles produced by distillation are collected in a sealed manner; Step 2: secondary distillation and purification, performing secondary distillation on the distillation pot bottom material in the distillation pot in step 1, and collecting the volatiles generated in this process; Step 3, collecting the distillation products, collecting the distillation products obtained in step 1 and step 2 to obtain a distilled 5N tellurium product; Step 4: zone melting and purification, the distilled 5N tellurium product obtained in step 3 is made into a rod, and placed in a zone melting furnace for zone melting and purification, and the volatiles generated in the zone melting furnace are sealed and collected; Step 5, separating the head and tail materials from the zone-melting 6N tellurium product. After the zone-melting purification in step 4 is completed, the head and tail materials of the rod-shaped distilled 5N tellurium product are separated and collected to finally obtain the zone-melting purified 6N tellurium product; Step 6: secondary zone melting purification, placing the zone melting purified 6N tellurium product separated in step 5 in a zone melting furnace for secondary zone melting purification operation, separating and collecting the head and tail materials of the product after the secondary zone melting purification operation, and finally obtaining a 7N tellurium product; Step seven: molding and packaging: molding and packaging the 7N tellurium product obtained in step six to finally obtain a 7N tellurium product.

2. The high-purity tellurium production process according to claim 1, characterized in that: The volatiles generated in step 1, step 2 and step 4 are collected by using pipelines, exhaust equipment and collection tanks, and the connections between the pipelines, collection tanks, distillation pots and zone furnaces are sealed using a thermal insulation sealing structure. The volatiles stored in the collection tanks are uniformly transported to relevant recycling companies for harmless treatment.

3. A high-purity tellurium production process according to claim 1, characterized in that: The distillation pots used in step one and step two are different, and the bottom material in the distillation pot in step one is scraped out with a scraper plate. At the same time, in step three, the distilled 5N tellurium products obtained in step one and step two are mixed and collected.

4. The high-purity tellurium production process according to claim 1, characterized in that: Before the distillation operation in step 1 and step 2, the 4N tellurium raw material and the distillation pot bottom material are crushed and preliminarily screened to make the material size be 50-100 mesh.

5. A high-purity tellurium production process according to claim 4, characterized in that: The distilled 5N tellurium product obtained in step three is sieved and mixed and then sintered into a rod with a similar overall outer diameter. The length of the rod-shaped distilled 5N tellurium product is set between 0.5m-1.0m, and its diameter is set between 0.15cm-0.20cm.

6. The high-purity tellurium production process according to claim 1, characterized in that: The separation positions of the head and tail materials of the tellurium products purified by zone melting collected in step 5 and step 6 are set at 0.1m-0.2m at the upper and lower ends of the tellurium products. The specific position standard for removing the head and tail materials is determined by referring to the color separation on the surface of the tellurium product after zone melting purification.

7. A high-purity tellurium production process according to claim 4, characterized in that: The tellurium product heads and tails collected in step five and step six are pre-put into a crusher for crushing, and finally the head and tails of the bulk tellurium product are obtained. In the subsequent purification process, the head and tails of the bulk tellurium product are mixed with the crushed 4N tellurium raw material, and sieved together. Finally, the mixture of the two is put into a distillation pot to repeat the work of step one.

8. A high-purity tellurium production process according to claim 1, characterized in that: In the step 5, after the tellurium product is purified by the first zone melting, the head and tail materials are removed after cooling to room temperature, and then the second zone melting purification is performed. After the second zone melting purification operation is completed, the head and tail materials are also cooled to room temperature before being removed and classified and collected.

9. A high-purity tellurium production process according to claim 1, characterized in that: After the distillation purification or zone melting purification in step 1, step 2 and step 4 is completed and the temperature drops to room temperature, continue to introduce room temperature air into the distillation pot and the zone melting furnace to facilitate the complete discharge and collection of volatiles and residual gases in the distillation pot and the zone melting furnace before opening the equipment for the next step.

10. A high-purity tellurium production process according to claim 1, characterized in that: When the 7N tellurium product is packaged in step seven, the 7N tellurium product obtained by the secondary zone melting purification is firstly cut and processed into a single block of 7N tellurium product weighing about 100g for packaging.

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