Device and method for preparing 6N high-purity tellurium

Abstract

The invention discloses a device and method for preparing 6N high-purity tellurium, and belongs to the technical field of high-purity tellurium preparation. The device comprises a heating container, an electromigration device, a heater and a ventilation pipeline; the heating container and the electromigration device are connected with each other, the heater is arranged on the outer side of the heating container, and the ventilation pipeline is used for introducing gas into the heating container; the electromigration device comprises an electromigration tank, a graphite electrode anode and a graphite electrode cathode, wherein the graphite electrode anode and the graphite electrode cathode are located on the two sides of the electromigration tank. According to the method for carrying out gas smelting and electromigration impurity removal on the 4N tellurium ingot, the weak oxidizing gas endows the tellurium melt with positive and negative charges so as to be used for impurity removal in the electromigration process, on the other hand, part of impurities float to the surface of the tellurium melt through stirring of the weak oxidizing gas, and the impurities on the surface layer are removed in a discharging mode; wherein impurities with positive and negative charges in the electromigration impurity removal melt are enriched towards the two ends of the electromigration device, so that the tellurium purity is improved from 4N to 6N level.

Description

Technical Field

[0001] The present invention relates to the technical field of high-purity tellurium preparation, and in particular to a device and method for preparing 6N high-purity tellurium. Background Art

[0002] Tellurium is a rare element. Due to its excellent semi-metallic properties, it is widely used in solar cells, infrared detection materials, thermoelectric refrigeration and other fields. It is known as the "vitamin of national cutting-edge technology and modern industry". In terms of detection materials, the substrate materials of cadmium zinc telluride (CZT) nuclear radiation detectors and mercury cadmium telluride (MCT) infrared detectors used in national defense, security, positioning and guidance are made of high-purity tellurium above 6N as raw materials. The purity of tellurium directly affects the performance of the material. Even a very small amount of impurities will greatly reduce the electrical properties of the material. Therefore, how to achieve economical and efficient preparation of high-purity tellurium above 6N has attracted much attention.

[0003] Regarding the method of preparing high-purity tellurium, the current mainstream process is to achieve it through vacuum distillation combined with regional melting. Vacuum distillation uses the properties of tellurium's low melting point and high vapor pressure to separate it from impurity elements. Generally, 4N tellurium can reach the 5N level of purity after vacuum distillation, and 5N distilled tellurium can reach the 6N or even 7N level after a certain number of regional melting. However, the output of vacuum distillation is limited by equipment, and regional melting is even more limited by efficiency, resulting in large-scale production of high-purity tellurium above 6N level has always been a problem that plagues the industry.

[0004] Patent CN 210528474 U effectively isolates the constant temperature section and the condensation section by using a draft tube in the vacuum distillation furnace, but the equipment is more complicated and the product purity and output are not significantly improved; Patent CN 116588902A proposes using multiple groups of heaters to form multiple melting zones, which does effectively improve the regional melting efficiency, but it also makes the regional melting equipment more complicated and the zone melting parameters difficult to control.

[0005] In view of this, this application is filed. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a device and method for preparing 6N high-purity tellurium, which effectively improves the purity of tellurium and prepares high-purity tellurium with a purity of 6N.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A device for preparing 6N high-purity tellurium comprises a heating container, an electromigration device, a heater and a ventilation duct; the heating container and the electromigration device are connected to each other, the heater is arranged outside the heating container, and the ventilation duct is used to pass gas into the heating container; the electromigration device comprises an electromigration groove and a graphite electrode anode and a graphite electrode cathode located on both sides of the electromigration groove.

[0009] The device described in the present invention uses the heating container and the electromigration device to remove impurities using gas smelting and electromigration to increase the tellurium purity from 4N to 6N level, thereby greatly improving the production efficiency of high-purity tellurium.

[0010] As a preferred embodiment of the present invention, the heating container is a graphite crucible.

[0011] As a preferred embodiment of the present invention, the graphite electrode anode is connected to the positive electrode of the external power supply, and the graphite electrode cathode is connected to the negative electrode of the external power supply.

[0012] The present invention also provides a method for preparing 6N high-purity tellurium, comprising the following steps:

[0013] (1) Adding a 4N tellurium ingot into a heating container and heating the tellurium ingot with a heater to melt the tellurium ingot;

[0014] (2) introducing a weak oxidizing gas at a pressure of 0.1 to 0.2 MPa into the heating container for 20 to 60 minutes. After the ventilation is completed, the container is kept warm;

[0015] (3) The melt enters an electromigration device, undergoes electromigration treatment, and is taken out to obtain a purified tellurium ingot;

[0016] (4) Knock off the two ends of the purified tellurium ingot to obtain 6N high-purity tellurium.

[0017] The present invention effectively improves the purity of tellurium by subjecting the 4N tellurium ingot to gas smelting and electromigration impurity removal, wherein a weak oxidizing gas imparts positive and negative charges to the tellurium melt for impurity removal in the electromigration process, and on the other hand, part of the impurities float to the surface of the tellurium melt through stirring by the weak oxidizing gas, and the surface impurities are removed by discharging the material downward; wherein the impurities with positive and negative charges in the electromigration impurity removal melt are enriched at both ends of the electromigration device, and then effectively purified, so that the tellurium purity is improved from 4N to 6N level.

[0018] As a preferred embodiment of the present invention, the heating temperature is 480-550°C.

[0019] As a preferred embodiment of the present invention, the weak oxidizing gas is a mixed gas of water vapor and argon or a mixed gas of carbon dioxide and argon.

[0020] As a preferred embodiment of the present invention, the volume ratio of water vapor to argon is (4-6): (94-96); and / or

[0021] The volume ratio of the carbon dioxide to the argon is (4-6):(94-96).

[0022] As a preferred embodiment of the present invention, the insulation temperature is 500-600° C., and the insulation time is 1-3 hours.

[0023] As a preferred embodiment of the present invention, the voltage of the electromigration treatment is 0.2-0.3V and the time is 1-4h.

[0024] As a preferred embodiment of the present invention, the knocking out of both ends of the purified tellurium ingot is specifically as follows: the knocking out length of the end close to the graphite electrode anode accounts for 10-20% of the total length; the knocking out length of the end far from the graphite electrode anode accounts for 20-25% of the total length.

[0025] The beneficial effect of the present invention is that: the present invention effectively improves the purity of tellurium by subjecting the 4N tellurium ingot to gas smelting and electromigration impurity removal, wherein the weak oxidizing gas imparts positive and negative charges to the tellurium melt for impurity removal during the electromigration process, and on the other hand, part of the impurities float to the surface of the tellurium melt through stirring by the weak oxidizing gas, and the surface impurities are removed by discharging the material downward; wherein the impurities with positive and negative charges in the electromigration impurity removal melt are enriched at both ends of the electromigration device, thereby effectively purifying the tellurium, so that the purity of the tellurium is increased from 4N to 6N level. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the device structure of the present invention.

[0027] Markings in the figure: 1. Ventilation duct; 2. Heating container; 3. Heater; 4. Solenoid valve; 5. Positive electrode; 6. Graphite electrode anode; 7. Electromigration tank; 8. Negative electrode; 9. Graphite electrode cathode. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0029] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0030] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0031] In the present application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0032] Unless otherwise specified, the components, raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the components and raw materials used in each parallel experiment are all of the same kind.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0034] The following examples are provided to facilitate understanding of the present invention. These examples are not provided to limit the scope of the claims.

[0035] Example 1

[0036] like Figure 1 As shown, this embodiment provides a device for preparing 6N high-purity tellurium, including a ventilation duct 1, a heating container 2, an electromigration device, and a heater 3; the heating container 2 and the electromigration device are connected to each other, the heater 3 is arranged on the outside of the heating container, and the ventilation duct is used to introduce gas into the heating container; the electromigration device includes an electromigration groove 7 and a graphite electrode anode 6 and a graphite electrode cathode 9 located on both sides of the electromigration groove.

[0037] In this embodiment, the heating container is a graphite crucible.

[0038] The graphite electrode anode is connected to the positive electrode 5 of the external power supply, and the graphite electrode cathode is connected to the negative electrode 8 of the external power supply.

[0039] The method for preparing 6N high-purity tellurium using the device for preparing 6N high-purity tellurium comprises the following steps:

[0040] (1) Adding a 4N tellurium ingot into a heating container and heating it to 500° C. by a heater to melt the tellurium ingot;

[0041] (2) After the tellurium ingot is completely melted, a weak oxidizing gas (5% CO 2 +95% Ar gas), ventilation time is 30min, after ventilation, keep at 600℃ for 2h;

[0042] (3) The melt enters the electromigration device, is electromigrated at 0.25V for 3 hours, and is taken out to obtain a purified tellurium ingot;

[0043] (4) Knock off the two ends of the purified tellurium ingot, with the knocked-off length of the end close to the graphite electrode anode accounting for 10% of the total length; and the knocked-off length of the end away from the graphite electrode anode accounting for 20% of the total length, to obtain 6N high-purity tellurium.

[0044] Example 2

[0045] The difference between Example 2 and Example 1 is that the method for preparing 6N high-purity tellurium is different (the apparatus is the same).

[0046] The method for preparing 6N high-purity tellurium using the device for preparing 6N high-purity tellurium comprises the following steps:

[0047] (1) Adding a 4N tellurium ingot into a heating container and heating it to 530° C. by a heater to melt the tellurium ingot;

[0048] (2) After the tellurium ingot is completely melted, a weak oxidizing gas (5% CO 2 +95% Ar gas), ventilation time is 40min, after ventilation, keep at 600℃ for 2.5h;

[0049] (3) The melt enters the electromigration device, is electromigrated at 0.25V for 4 hours, and is taken out to obtain a purified tellurium ingot;

[0050] (4) Knock off the two ends of the purified tellurium ingot, with the knocked-off length of the end close to the graphite electrode anode accounting for 10% of the total length; and the knocked-off length of the end away from the graphite electrode anode accounting for 20% of the total length, to obtain 6N high-purity tellurium.

[0051] Example 3

[0052] The difference between Example 2 and Example 1 is that the method for preparing 6N high-purity tellurium is different (the apparatus is the same).

[0053] The method for preparing 6N high-purity tellurium using the device for preparing 6N high-purity tellurium comprises the following steps:

[0054] (1) Adding a 4N tellurium ingot into a heating container and heating it to 550° C. by a heater to melt the tellurium ingot;

[0055] (2) After the tellurium ingot is completely melted, a weak oxidizing gas (5% CO 2 +95% Ar gas), ventilation time is 60min, after ventilation, keep at 600℃ for 3h;

[0056] (3) The melt enters the electromigration device, is electromigrated at 0.25V for 4 hours, and is taken out to obtain a purified tellurium ingot;

[0057] (4) Knock off the two ends of the purified tellurium ingot, with the knocked-off length of the end close to the graphite electrode anode accounting for 10% of the total length; and the knocked-off length of the end away from the graphite electrode anode accounting for 20% of the total length, to obtain 6N high-purity tellurium.

[0058] Example 4

[0059] The difference between Example 4 and Example 1 is that the voltage of the electromigration treatment is 0.2V, and the other aspects are the same.

[0060] Example 5

[0061] The difference between Example 5 and Example 1 is that the voltage of the electromigration treatment is 0.3 V, and the other aspects are the same.

[0062] Comparative Example 1

[0063] The difference between Comparative Example 1 and Example 1 is that the voltage of the electromigration treatment is 0.1 V, and the other aspects are the same.

[0064] Comparative Example 2

[0065] The difference between Comparative Example 2 and Example 1 is that the voltage of the electromigration treatment is 0.4 V, and the other aspects are the same.

[0066] Comparative Example 3

[0067] The difference between Comparative Example 3 and Example 1 is that pure argon is used to replace the weak oxidizing gas, and the other aspects are the same.

[0068] Comparative Example 4

[0069] The difference between Comparative Example 4 and Example 1 is that pure carbon dioxide gas is used to replace the weak oxidizing gas, and the other conditions are the same.

[0070] Test Case

[0071] The same batch of 4N tellurium ingots was treated according to the methods of the embodiment and the comparative example, and the purity after treatment is shown in Table 1.

[0072] Table 1

[0073] element Mg Al Ca Fe Ni Cu Zn Se Ag Cd Pb Example 1 0.01 0.01 0.06 0.01 0.01 0.01 0.05 0.05 0.01 0.03 0.01 Example 2 0.01 0.01 0.07 0.01 0.01 0.01 0.05 0.02 0.01 0.05 0.01 Example 3 0.01 0.01 0.05 0.01 0.01 0.01 0.05 0.03 0.01 0.04 0.01 Example 4 0.03 0.01 0.08 0.01 0.01 0.01 0.05 0.05 0.01 0.03 0.01 Example 5 0.01 0.01 0.05 0.01 0.01 0.01 0.06 0.05 0.01 0.05 0.01 Comparative Example 1 0.25 0.19 0.34 0.07 0.14 0.04 0.25 0.23 0.17 0.04 0.02 Comparative Example 2 0.01 0.01 0.03 0.01 0.01 0.43 0.05 0.03 0.19 0.45 0.09 Comparative Example 3 0.36 0.23 0.13 0.89 0.31 0.29 0.17 1.1 0.15 0.12 0.98 Comparative Example 4 0.12 0.13 0.27 0.09 0.02 0.07 0.18 0.08 0.42 0.45 0.04

[0074] As can be seen from Table 1, the present invention effectively improves the purity of tellurium by subjecting the 4N tellurium ingot to gas smelting and electromigration impurity removal, wherein the weak oxidizing gas imparts positive and negative charges to the tellurium melt for impurity removal during the electromigration process, and on the other hand, part of the impurities float to the surface of the tellurium melt by stirring with the weak oxidizing gas, and the surface impurities are removed by discharging the material downward; wherein the impurities with positive and negative charges in the electromigration impurity removal melt are enriched at both ends of the electromigration device, thereby effectively purifying the tellurium, thereby improving the tellurium purity from 4N to 6N level.

[0075] By comparing Example 1 with Comparative Examples 1 to 2, it can be seen that the voltage is a key parameter of the present invention. If the voltage is too low, complete electromigration cannot be achieved and the electromigration effect is poor. If the voltage is too high, side reactions will occur, which will also affect the purity. Therefore, the present invention requires strict control of the voltage range of electromigration.

[0076] By comparing Example 1 with Comparative Examples 3 to 4, it can be seen that the weak oxidizing gas described in the present invention is the key to achieving the effect of the present invention. The weak oxidizing gas imparts positive and negative charges to the tellurium melt for impurity removal during the electromigration process. On the other hand, the weak oxidizing gas is stirred to make some impurities float to the surface of the tellurium melt, and the surface impurities are removed by discharging the material. The gas without oxidizing property cannot impart positive and negative charges to the tellurium melt, and the reducing gas cannot achieve the purpose of imparting charges to the tellurium melt. The strong oxidizing gas will cause excessive tellurium loss.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A device for preparing 6N high-purity tellurium, characterized in that: It includes a heating container, an electromigration device, a heater and a ventilation duct; the heating container and the electromigration device are connected to each other, the heater is arranged on the outside of the heating container, and the ventilation duct is used to introduce gas into the heating container; the electromigration device includes an electromigration groove and a graphite electrode anode and a graphite electrode cathode located on both sides of the electromigration groove.

2. The device for preparing 6N high-purity tellurium according to claim 1, characterized in that: The heating container is a graphite crucible.

3. The device for preparing 6N high-purity tellurium according to claim 1, characterized in that: The graphite electrode anode is connected to the positive electrode of an external power source, and the graphite electrode cathode is connected to the negative electrode of the external power source.

4. A method for preparing 6N high-purity tellurium, characterized in that: The following steps are involved: (1) Adding a 4N tellurium ingot into a heating container and heating the tellurium ingot with a heater to melt the tellurium ingot; (2) introducing a weak oxidizing gas at a pressure of 0.1 to 0.2 MPa into the heating container for 20 to 60 minutes. After the ventilation is completed, the container is kept warm; (3) The melt enters an electromigration device, undergoes electromigration treatment, and is taken out to obtain a purified tellurium ingot; (4) Knock off the two ends of the purified tellurium ingot to obtain 6N high-purity tellurium.

5. The method for preparing 6N high-purity tellurium according to claim 4, characterized in that: The heating temperature is 480-550°C.

6. The method for preparing 6N high-purity tellurium according to claim 4, characterized in that: The weak oxidizing gas is a mixed gas of water vapor and argon or a mixed gas of carbon dioxide and argon.

7. The method for preparing 6N high-purity tellurium according to claim 6, characterized in that: The volume ratio of water vapor to argon is (4-6): (94-96); and / or The volume ratio of the carbon dioxide to the argon is (4-6):(94-96).

8. The method for preparing 6N high-purity tellurium according to claim 4, characterized in that: The insulation temperature is 500-600° C., and the insulation time is 1-3 hours.

9. The method for preparing 6N high-purity tellurium according to claim 4, characterized in that: The voltage of the electromigration treatment is 0.2-0.3V, and the time is 1-4h.

10. The method for preparing 6N high-purity tellurium according to claim 4, characterized in that: The knocking out of the two ends of the purified tellurium ingot is specifically as follows: the knocking out length of the end close to the graphite electrode anode accounts for 10-20% of the total length; the knocking out length of the end far from the graphite electrode anode accounts for 20-25% of the total length.

Images