A method for preparing high-purity germanium ingot by vacuum melting and casting germanium powder

Abstract

The application discloses a method for preparing high-purity germanium ingot by reducing germanium powder vacuum melting and casting ingot, which comprises the following steps: first, cleaning and loading the graphite boat; second, vacuumizing; third, passing in nitrogen containing 1% hydrogen; fourth, heating and melting and casting ingot; fifth, cooling; sixth, continuously passing in high-purity nitrogen, and waiting for the furnace body to restore normal temperature and pressure; seventh, taking out the material from the furnace. The high-purity reduced germanium powder is cast into ingot in a high-temperature ingot casting furnace under a vacuum nitrogen protection atmosphere, so that a large amount of hydrogen is avoided, production cost and safety risk are reduced, production efficiency is improved, and production cost is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rare metal metallurgy, and particularly relates to a method for preparing high-purity germanium ingot by vacuum melting and casting of reduced germanium powder. BACKGROUND

[0002] In industrial production of high-purity germanium, germanium concentrate is usually chlorinated in a chlorination distillation reaction kettle, distilled, re-distilled, purified by rectification, hydrolyzed, filtered, dried to obtain high-purity germanium dioxide, and then reduced by high-purity hydrogen to obtain high-purity germanium powder. The high-purity germanium powder is then melted and cast to obtain high-purity germanium polycrystal ingot, and then single crystal growth is performed to obtain high-purity germanium single crystal, which is processed into germanium single crystal wafer and used in different application fields such as solar satellite power supply, infrared thermal imager, and high-purity germanium detector. The casting process of high-purity reduced germanium powder can make the trace impurities more uniformly distributed in the entire ingot, ensure the consistency and stability of the germanium material performance, make germanium atoms tightly combined, increase the density and strength of the germanium material, improve the reliability of the germanium material, and also remove part of the impurities to form the required crystal shape, facilitating subsequent zone melting and purification.

[0003] Currently, the conventional casting process of high-purity reduced germanium powder is as follows: after high-purity germanium dioxide (650-700℃) in a graphite boat is reduced by hydrogen to obtain high-purity reduced germanium powder, the temperature is further increased to 1050℃, which is higher than the melting point of germanium metal (937℃), so that the reduced germanium powder is melted into liquid germanium metal. After a period of stable heat preservation, the liquid germanium metal is slowly cooled to room temperature, and then solidified to obtain high-purity germanium ingot. The existing technology obtains high-purity germanium by improving the zone melting environment, zone melting conditions, and raw materials, and does not involve obtaining germanium polycrystal by vacuum melting and casting of high-purity reduced germanium powder. SUMMARY

[0004] The purpose of the present application is to provide a method for preparing high-purity germanium ingot by vacuum melting and casting of high-purity reduced germanium powder, so as to facilitate subsequent zone melting and purification.

[0005] To solve the above problems, the present application provides a method for preparing high-purity germanium ingot by vacuum melting and casting of reduced germanium powder, characterized in that it comprises the following steps:

[0006] The first step is to clean and load the graphite boat; 3000 to 3500 g of high-purity germanium powder is weighed into a single graphite boat, the graphite boat is then placed horizontally on the graphite boat support in the corresponding fixed graphite boat groove, and the graphite boat support is slowly placed in the vacuum melting and casting furnace, the furnace cover is closed, and the furnace body is completely closed and sealed; the vacuum melting and casting furnace is composed of a furnace body, a furnace cover, a vacuum pump and a graphite boat support; the furnace cover is arranged on the furnace body, the furnace cover is provided with a water circulation pipeline, and the furnace cover is provided with a discharge pipeline and a pressure gauge; the furnace body is a hollow cylinder, and a vacuum furnace chamber is arranged in the furnace body; the furnace body is provided with an exhaust pipe connected with the vacuum pump; heating resistance bands are arranged in a corrugated shape around the furnace body;

[0007] The second step is to extract vacuum;

[0008] The third step is to introduce nitrogen containing 1% hydrogen;

[0009] The fourth step is to heat and melt the ingot; first, preheat treatment is performed to raise the temperature in the furnace to 200 to 230 DEG C and maintain for 40 min; then, the temperature is raised to 650 to 680 DEG C at a rate of 6 to 7 DEG C / min and maintained for 120 min; then, the temperature is raised to 750 to 780 DEG C and maintained for 120 min; then, the temperature is raised to 900 to 930 DEG C at a rate of 4 to 5 DEG C / min and maintained for 40 min; then, the temperature is raised to 1000 to 1030 DEG C at a rate of 4 to 5 DEG C / min and maintained for 60 min for ingot casting;

[0010] The fifth step is to cool down; after the ingot casting time, the temperature is controlled to decrease steadily; after the ingot casting is completed, the temperature is rapidly decreased to 800 DEG C at a rate of 5 to 6 DEG C / min, which helps to inhibit the adverse phase change and excessive growth of the microstructure at high temperature; during 800 DEG C to 500 DEG C, the rate is 2 to 3 DEG C / min, because the phase change of germanium is sensitive at this stage, and fast cooling will increase the internal stress and form structural defects; below 500 DEG C, the rate is 2 DEG C / min, which further reduces the cooling rate, which is beneficial to reduce the generation of cracks until the cooling is completed;

[0011] The sixth step is to continue to introduce high-purity nitrogen until the furnace body returns to normal temperature and pressure;

[0012] The seventh step is to take out the material from the furnace.

[0013] Further, the graphite boat is cleaned by placing the high-purity graphite boat in the prepared aqua regia for 24 h, then placing it in deionized water and heating to boiling, repeating the cleaning 8 to 10 times, and finally placing the graphite boat in the vacuum melting and casting furnace for drying, heating to a temperature of 1000 DEG C, and then taking out the graphite boat after cooling, and wiping it clean with alcohol.

[0014] Further, the vacuum is drawn by opening the exhaust pipe valve, then opening the pressure gauge valve, and then opening the vacuum pump power switch, until the vacuum pressure gauge shows less than 50 Pa and remains stable for 40 to 45 min, then the vacuum pump is closed, and this process lasts about 20 min.

[0015] Further, the nitrogen containing 1% hydrogen is introduced by slowly opening the nitrogen pipeline, first introducing high-purity nitrogen at a rate of 10 to 20 L / min, maintaining for 30 to 50 min, then adjusting the rate to 30 to 40 L / min and maintaining, then maintaining for 30 to 50 min, until the vacuum pressure gauge shows 50,000 to 84,100 Pa and remains stable for 40 min, indicating that the nitrogen filling is completed and the vacuum reaches the required value, and this step is repeated 3 times; then high-purity hydrogen is introduced at a rate of 3 to 5 L / min and maintained for 5 min, until the vacuum pressure gauge shows about 50,500 to 84,940 Pa and remains stable for 40 min, indicating that a nitrogen atmosphere containing 1% hydrogen is formed. A small amount of hydrogen is filled in the nitrogen to prevent the reduced germanium powder from being oxidized to germanium dioxide by a small amount of oxygen.

[0016] Further, the high-purity nitrogen is continuously introduced, and after the furnace body returns to normal temperature and pressure and cooling is completed, the nitrogen pipeline is opened, high-purity nitrogen is introduced at a rate of 25 to 50 L / min and maintained for about 20 to 30 min, until the vacuum pressure gauge shows about 101,000 Pa, indicating that the pressure in the furnace returns to normal pressure, and the gas introduction is stopped.

[0017] Further, after the temperature and pressure in the furnace return to normal temperature and pressure, the furnace cover is lifted, the support is removed, the graphite boat is removed from the support, and the high-purity germanium ingot is removed from the graphite boat.

[0018] The above technical scheme of the present application has the following beneficial technical effects: the high-purity reduced germanium powder is cast into ingots in a vacuum nitrogen protective atmosphere by a high-temperature casting furnace, avoiding the participation of a large amount of hydrogen, reducing production cost and safety risk. Since multiple graphite boats can be placed in the vacuum furnace body for each operation, the processing capacity reaches 120 kg, the production time required is correspondingly reduced, the single-furnace yield is greatly improved, the production efficiency is improved, and the production cost is reduced. The power of the device can be controlled in real time according to needs, the power consumption required during production is reduced, and the problem of uneven product performance caused by temperature difference is also reduced. The device is vertically placed, which is conducive to complete vacuumization and shortens the process time. After the temperature is raised, the nitrogen flow rate is reduced, the heat carried away by the nitrogen is inhibited, and the amount of high-purity nitrogen used is saved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a flow chart of a method for preparing high-purity germanium ingots by vacuum melting and casting of reduced germanium powder;

[0020] Figure 2 is a vacuum melting furnace structure diagram;

[0021] Figure 3 is a graphite boat support top view.

[0022] Reference signs:

[0023] 1: furnace body; 2: furnace cover; 3: graphite boat support; 4: water circulation pipeline; 5: exhaust pipeline; 6: pressure gauge; 7: vacuum furnace chamber; 8: exhaust pipe; 9: heating resistance band; 10: graphite boat. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the present application is further described in detail below in combination with specific embodiments and with reference to the drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0025] As shown in Figure 1 , a method for preparing high-purity germanium ingot by reducing germanium powder vacuum melting and casting ingot is provided, characterized in that it comprises the following steps:

[0026] First step, cleaning and loading of graphite boat; place the high-purity graphite boat in the prepared aqua regia for 24 h, then place it in deionized water and heat to boiling, repeat the cleaning for 8 to 10 times, finally dry the graphite boat in the vacuum melting and casting ingot furnace, heat to a temperature of 1000℃, take out the graphite boat after cooling, and clean it with alcohol. Weigh 3000 to 3500 g of high-purity reduced germanium powder into a single graphite boat, then place the graphite boat horizontally on the graphite boat support in the corresponding groove for fixing the graphite boat, then slowly place the graphite boat support in the vacuum melting and casting ingot furnace, cover the furnace cover, and make the furnace body completely closed and sealed; as shown in Figure 2 and Figure 3 , the vacuum melting and casting ingot furnace is composed of a furnace body 1, a furnace cover 2, a vacuum pump and a graphite boat support 3; the furnace cover 2 is arranged on the furnace body 1, the furnace cover 2 is provided with a water circulation pipeline 4, the furnace cover 2 is provided with an exhaust pipeline 5 and a pressure gauge 6; the furnace body 1 is a hollow cylinder, the inside is provided with a vacuum furnace chamber 7, the furnace body 1 is provided with an exhaust pipe 8 connected with the vacuum pump; the periphery of the furnace body is provided with a heating resistance band 9 wound in a corrugated shape;

[0027] Second step, vacuum pumping; open the exhaust pipe valve, then open the pressure gauge valve, and then turn on the vacuum pump power switch, until the vacuum pressure gauge shows less than 50 Pa and the vacuum degree remains stable for 40 to 45 min, then turn off the vacuum pump, this process lasts about 20 min;

[0028] Third step, nitrogen containing 1% hydrogen; slowly open the nitrogen pipeline, first with 10 to 20 L / min rate of high purity nitrogen, keep 30 to 50 min, then the rate is adjusted to 30 to 40 L / min, keep unchanged, keep 30 to 50 min, until the vacuum pressure gauge shows 50000 to 84100 Pa and keep 40 min vacuum stable, indicating that the nitrogen filling is completed and the vacuum reaches the required, repeat this step 3 times; then with 3 to 5 L / min rate of high purity hydrogen and keep 5 min, until the vacuum pressure gauge shows 50500 to 84940 Pa or so and keep 40 min vacuum stable, indicating that a nitrogen atmosphere containing 1% hydrogen is formed. A small amount of hydrogen is filled in the nitrogen to prevent the reduced germanium powder from being oxidized to germanium dioxide by trace oxygen;

[0029] Fourth step, heating and melting ingot; first preheat treatment, the temperature in the furnace is raised to 200 to 230℃, keep 40 min; then the temperature is raised to 650 to 680℃ at a rate of 6 to 7℃ / min, keep 120 min; then the temperature is raised to 750 to 780℃, keep 120 min, the temperature is raised to 900 to 930℃ at a rate of 4 to 5℃ / min, keep 40 min, the temperature is raised to 1000 to 1030℃ at a rate of 4 to 5℃ / min, keep constant temperature 60 min for ingot casting;

[0030] Fifth step, cooling; after the ingot time, control the temperature to drop steadily; after the ingot casting, it is dropped to 800℃ interval with 5 to 6℃ / min fast cooling, which helps to inhibit the adverse phase change and excessive growth of microstructure at high temperature; during 800℃-500℃, the rate is 2 to 3℃ / min, because the phase change of germanium is sensitive, too fast cooling will lead to increased internal stress and formation of structural defects; below 500℃, the rate is 2℃ / min, further reducing the cooling rate, which is conducive to reducing the generation of cracks, until the cooling is completed;

[0031] Sixth step, continue to pass high purity nitrogen, wait for the furnace body to recover to normal temperature and pressure; after cooling, open the nitrogen pipeline, pass high purity nitrogen at a rate of 25 to 50 L / min and keep for 20 to 30 min or so, until the vacuum pressure gauge shows about 101000 Pa, indicating that the pressure in the furnace returns to normal pressure, stop passing gas;

[0032] Seventh step, take out the material; after the temperature and pressure in the furnace recover to normal temperature and pressure, raise the furnace cover, take out the support, then take out the graphite boat from the support, and then take out the high purity germanium ingot from the graphite boat.

[0033] A method for casting ingot of high purity reduced germanium powder by using vacuum melting ingot furnace, Table 1 below is the comparison between the present application and the conventional horizontal atmospheric pressure tubular quartz reduction furnace casting method:

[0034] Table 1 Comparison between vacuum furnace melting ingot method and conventional quartz tubular reduction casting method

[0035] Reduced germanium powder ingot casting method Vacuum ingot casting furnace melting ingot method Quartz tube reduction furnace ingot casting method Use equipment Vacuum melting ingot furnace Quartz tube reduction furnace Furnace body placement method Vertical placement Horizontal placement Single furnace boat loading capacity 40 boats per furnace, each boat loaded with 3 kg of high purity reduced germanium powder, Ge≥99.999% 1 boat per furnace, loaded with 2.5 kg of high purity germanium dioxide Single furnace high purity germanium ingot yield (kg) 120 1.7 Single furnace single time consumption (h) 8, only ingot casting 24, reduction + ingot casting Ingot casting equipment power (KW) 200 (adjustable) 30 (adjustable) Design maximum temperature (℃) 1100 1100 Use gas High purity nitrogen gas (purity≥99.999%) + 1% high purity hydrogen gas High purity hydrogen gas (purity≥99.999%) Cooling method Real-time temperature control cooling Natural cooling Ingot furnace lining Ceramic fiber high pressure module High temperature refractory, asbestos Heating element 0Cr25AL5 resistance strip Conventional resistance wire

[0036] Example 1: A method for vacuum casting of high purity reduced germanium powder to obtain high purity germanium ingot, the specific steps are as follows:

[0037] First, cleaning and loading of graphite boat:

[0038] First, place the high-purity graphite boat in the prepared aqua regia (nitric acid: hydrochloric acid = 1:3) for 24 hours, then place it in deionized water and heat to boiling, repeat this step 8 times, finally dry the graphite boat in a vacuum furnace, heat the temperature to about 1000 ℃, after cooling, take out the graphite boat, and clean it with alcohol.

[0039] Weigh 3000 g of high-purity reduced germanium powder into a single graphite boat and evenly spread it out to avoid stacking. After filling the entire furnace with 40 graphite boats, place the graphite boats horizontally in the corresponding fixed graphite boat grooves on the support, then slowly place the support in the vacuum furnace tank, press the operation button to control the furnace cover to slowly descend until it is completely closed and sealed with the furnace body.

[0040] Second, vacuumizing:

[0041] After the furnace cover is completely sealed, open the exhaust valve and begin vacuumizing. Before vacuumizing, check the status of the vacuum pump to ensure it is normal, then open the pressure gauge valve and turn on the vacuum pump power switch. When the vacuum pressure gauge shows less than 50 Pa and the vacuum degree remains stable for 45 minutes, it indicates that the vacuum degree meets the requirements, so turn off the vacuum pump. This process takes about 20 minutes.

[0042] Third, introduce nitrogen gas containing 1% hydrogen:

[0043] Slowly open the nitrogen pipeline, first with 20 L / min rate of high purity nitrogen, keep 30 min, then the rate to 30 L / min keep, keep 30 min, until the vacuum pressure gauge shows 50000 Pa and keep 40 min vacuum stable, show that the nitrogen filling is completed and the vacuum reaches the requirements, repeat this step 3 times. Again with 3 L / min rate of high purity hydrogen and keep 5 min, until the vacuum pressure gauge shows 50500 Pa or so and keep 40 min vacuum stable, show that a vacuum high purity nitrogen (containing 1% high purity hydrogen) atmosphere environment is formed. A small amount of hydrogen is filled in the nitrogen, which can prevent the reduced germanium powder from being oxidized to germanium dioxide by trace oxygen.

[0044] Fourth step, heating and melting ingot:

[0045] First, preheat treatment, the temperature in the furnace to 200 ℃, keep 40 min, to reduce thermal stress; then with 6 ℃ / min rate to 650 ℃, keep 120 min; then to 750 ℃, keep 120 min, with 4 ℃ / min rate to 900 ℃, keep 40 min, with 4 ℃ / min rate to 1000 ℃, keep 1000 ℃ constant temperature 60 min for ingot casting.

[0046] Fifth step, cooling:

[0047] After the ingot time, control the temperature to drop steadily; in the 1000 ℃-800 ℃ interval after the ingot is completed, use 5 ℃ / min rapid cooling, which helps to inhibit the adverse phase change and excessive growth of microstructure at high temperature; during 800 ℃-500 ℃, the cooling speed needs to be slowed down, use 2 ℃ / min rate, because this stage germanium phase change is sensitive, too fast cooling will lead to increased internal stress and structure defects; below 500 ℃, use 2 ℃ / min rate, further reduce the cooling rate, which is conducive to reducing the generation of cracks.

[0048] Sixth step, continue to fill in high purity nitrogen, wait for the furnace body to restore normal temperature and pressure:

[0049] After cooling, open the nitrogen pipeline, with 50 L / min rate of high purity nitrogen keep 30 min or so, until the vacuum pressure gauge shows 101000 Pa or so, show that the furnace pressure returned to normal pressure, stop filling gas. After stopping the gas, need to wait for a period of time, make the internal pressure and temperature stable, temperature drop to 30 ℃, reach normal temperature and pressure, prepare to open the furnace and discharge.

[0050] Seventh step, discharge and take out the material:

[0051] After the temperature and pressure in the furnace recover to normal temperature and pressure, press the operation button to raise the furnace cover, slowly take out the support, then take out the graphite boat from the support, and finally take out the high-purity germanium ingot from the graphite boat and transfer it to a high-purity zone melting graphite boat for subsequent zone melting purification.

[0052] Example 2: A method for vacuum ingot casting of high-purity reduced germanium powder to obtain high-purity germanium polycrystal, the specific steps are as follows:

[0053] First step, cleaning and loading of the graphite boat:

[0054] First, place the high-purity graphite boat in the prepared aqua regia (nitric acid: hydrochloric acid = 1:3) for 24 hours, then place it in deionized water and heat to boiling, repeat this step 10 times, finally place the graphite boat in a vacuum furnace and dry it, heat the temperature to 1000 ℃, and then take out the graphite boat after cooling, and clean it with alcohol.

[0055] Weigh 3500 g of high-purity reduced germanium powder into a single graphite boat and evenly spread it out to avoid stacking. After filling the entire furnace with 40 graphite boats, place the graphite boats horizontally on the support in the corresponding groove of the fixed graphite boat. Then slowly place the support in the vacuum furnace tank, press the operation button to control the furnace cover to slowly descend until it is completely closed and sealed with the furnace body.

[0056] Second step, vacuum pumping:

[0057] After the furnace cover is completely lowered and sealed, open the exhaust valve and start vacuum pumping. Before vacuum pumping, check the status of the vacuum pump to ensure it is normal. Then open the pressure gauge valve and turn on the vacuum pump power switch. When the vacuum pressure gauge shows less than 50 Pa and remains stable for 40 minutes, it indicates that the vacuum degree has reached the required level. Turn off the vacuum pump. This process takes about 20 minutes.

[0058] Third step, introduce nitrogen gas containing 1% hydrogen:

[0059] Slowly open the nitrogen gas pipeline. First, introduce high-purity nitrogen gas at a rate of 10 L / min for 50 minutes. Then adjust the rate to 40 L / min and keep it unchanged for another 50 minutes. When the vacuum pressure gauge shows 84100 Pa and remains stable for 40 minutes, it indicates that the nitrogen filling is complete and the vacuum degree has reached the required level. Repeat this step 3 times. Then introduce high-purity hydrogen gas at a rate of 5 L / min and keep it for 5 minutes. When the vacuum pressure gauge shows around 84940 Pa and remains stable for 40 minutes, it indicates that a vacuum high-purity nitrogen gas environment containing 1% high-purity hydrogen gas has been formed. The small amount of hydrogen gas in the nitrogen gas can prevent the reduced germanium powder from being oxidized to germanium dioxide by trace amounts of oxygen.

[0060] Fourth step, temperature heating melting ingot:

[0061] First, preheating treatment, the temperature in the furnace to 230 ℃, keep 40 min, to reduce thermal stress; then, the temperature to 680 ℃ at a rate of 7 ℃ / min, keep 120 min; temperature to 780 ℃, keep 120 min, temperature to 930 ℃ at a rate of 5 ℃ / min, keep 40 min, temperature to 1030 ℃ at a rate of 5 ℃ / min, keep 1030 ℃ constant temperature 60 min for ingot casting.

[0062] Fifth step, cooling down:

[0063] After the ingot time, control temperature steady decline; in just finished ingot after 1030 ℃-800 ℃, 6 ℃ / min rapid cooling, this helps to inhibit the adverse phase change at high temperature and excessive growth of microstructure; in 800 ℃-500 ℃, cooling rate needs to slow down, using 3 ℃ / min rate, because this stage germanium phase change is sensitive, cooling too fast will lead to increased internal stress and formation of structural defects; below 500 ℃, using 2 ℃ / min rate, further reduce the cooling rate, this is conducive to reducing the generation of cracks.

[0064] Sixth step, continue to pass in high purity nitrogen, when the furnace body restores normal temperature and pressure:

[0065] After the completion of cooling, open nitrogen pipeline, with 25 L / min rate of high purity nitrogen for about 20 min, until the vacuum pressure gauge shows 101000 Pa or so that the furnace gas pressure back to normal, stop the gas. After stopping ventilation need to wait for a period of time, so that the internal pressure and temperature stable, temperature drop to 30 ℃, to normal temperature and pressure, ready to open furnace discharge.

[0066] Seventh step, out of the furnace and take out the material:

[0067] After the furnace temperature and pressure to restore normal temperature and pressure, press the operation button to lift the furnace cover, slowly take out the support, then take out the graphite boat from the support, then take out the high purity germanium ingot from the graphite boat and transfer to the high purity zone melting graphite boat for subsequent zone melting purification.

[0068] It should be understood that the above specific embodiments of the present application are only used for example or explanation of the principles of the present application, and do not constitute a limitation on the present application. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the appended claims of the present application are intended to cover all variations and modifications falling within the scope and boundary of the appended claims, or the equivalent forms of such scope and boundary.

Claims

1. A method of producing a high purity germanium ingot by vacuum melting of reduced germanium powder, characterized by, It comprises the following steps: The first step is to clean and load the graphite boat. 3000 to 3500 g of high-purity reduced germanium powder is weighed into a single graphite boat, which is then placed horizontally in the corresponding fixed graphite boat groove on the graphite boat support, and then the graphite boat support is slowly placed in the vacuum melting and ingot casting furnace, the furnace cover is closed, and the furnace body is completely closed and sealed; the vacuum melting and ingot casting furnace is composed of a furnace body, a furnace cover, a vacuum pump and a graphite boat support; the furnace cover is arranged on the furnace body, and the furnace cover is provided with a water circulation pipeline, a discharge pipeline and a pressure gauge; the furnace body is a hollow cylinder, and a vacuum furnace chamber is arranged inside; the furnace body is provided with an exhaust pipe connected with the vacuum pump; heating resistance bands are arranged around the furnace body in a corrugated shape; The second step is to evacuate the vacuum. The third step is to introduce nitrogen containing 1% hydrogen. The fourth step is to heat and melt the ingot; first, preheat treatment is performed to raise the temperature in the furnace to 200 to 230℃ and maintain for 40 min; then, the temperature is raised to 650 to 680℃ at a rate of 6 to 7℃ / min and maintained for 120 min; then, the temperature is raised to 750 to 780℃ and maintained for 120 min; then, the temperature is raised to 900 to 930℃ at a rate of 4 to 5℃ / min and maintained for 40 min; then, the temperature is raised to 1000 to 1030℃ at a rate of 4 to 5℃ / min and maintained for 60 min for ingot casting; The fifth step is to cool down; after the ingot casting time, the temperature is controlled to decrease steadily; after the ingot casting is completed, the temperature is rapidly decreased to 800℃ at a rate of 5 to 6℃ / min; during 800℃-500℃, the temperature is decreased at a rate of 2 to 3℃ / min; below 500℃, the temperature is decreased at a rate of 2℃ / min until the cooling is completed; The sixth step is to continue to introduce high-purity nitrogen until the temperature in the furnace body returns to normal temperature and pressure. The seventh step is to take out the material from the furnace.

2. The method of producing a high purity germanium ingot from reduced germanium powder vacuum melted ingot according to claim 1, characterized by, The graphite boat is cleaned by placing it in prepared aqua regia for 24 h, then placing it in deionized water and heating to boiling, repeating the cleaning 8 to 10 times, and finally drying the graphite boat in the vacuum melting and ingot casting furnace by heating to a temperature of 1000℃, then taking out the graphite boat after cooling, and wiping it clean with alcohol.

3. The method of claim 1, wherein the high purity germanium ingot is produced by vacuum melting and casting of reduced germanium powder, and the reduced germanium powder is produced by the method of claim 1. The vacuum is evacuated by opening the exhaust pipe valve, then opening the pressure gauge valve, and then turning on the vacuum pump power switch until the vacuum pressure gauge shows less than 50 Pa and remains stable for 40 to 45 min, then closing the vacuum pump.

4. The method of claim 1, wherein the high purity germanium ingot is produced by vacuum melting and casting of reduced germanium powder. The nitrogen containing 1% hydrogen is introduced by slowly opening the nitrogen pipeline, first introducing high-purity nitrogen at a rate of 10 to 20 L / min for 30 to 50 min, then adjusting the rate to 30 to 40 L / min and keeping it unchanged for another 30 to 50 min, until the vacuum pressure gauge shows 50,000 to 84,100 Pa and keeps stable for 40 min, indicating that the nitrogen filling is completed and the vacuum degree reaches the required value; then high-purity hydrogen is introduced at a rate of 3 to 5 L / min and kept for 5 min, until the vacuum pressure gauge shows 50,500 to 84,940 Pa and keeps stable for 40 min, indicating that a nitrogen atmosphere containing 1% hydrogen is formed.

5. The method of claim 1, wherein the high purity germanium ingot is produced by vacuum melting and casting of reduced germanium powder. The high-purity nitrogen continues to be introduced, and after the furnace body recovers to normal temperature and pressure and cooling is completed, the nitrogen pipeline is opened, high-purity nitrogen is introduced at a rate of 25 to 50 L / min and kept for 20 to 30 min, until the vacuum pressure gauge shows 101,000 Pa, indicating that the pressure in the furnace returns to normal pressure, and the gas introduction is stopped.

6. The method of claim 1, wherein the high purity germanium ingot is produced by vacuum melting and casting of reduced germanium powder. After the temperature and pressure in the furnace recover to normal temperature and pressure, the furnace cover is lifted, the support is taken out, the graphite boat is taken out from the support, and the high-purity germanium ingot is taken out from the graphite boat.

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