Device and method for preparing high-purity germanium powder by reducing germanium dioxide through hydrogen

Abstract

The embodiment of the invention relates to a device and method for preparing high-purity germanium powder by reducing germanium dioxide through hydrogen, and belongs to the technical field of germanium metallurgy and high-purity germanium material preparation. According to the device for preparing the high-purity germanium powder through hydrogen reduction of germanium dioxide, the device for preparing the high-purity germanium powder through hydrogen reduction of germanium dioxide comprises a furnace body, a furnace tube is arranged in the furnace body in a penetrating mode, the two ends of the furnace tube extend out of the furnace body and are fixed through a furnace tube support, and the furnace tube support is fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug are sequentially arranged in the furnace tube from bottom to top, and a gap exists between the graphite crucible assembly and the furnace plug. The use amount of hydrogen is greatly reduced, the hydrogen utilization rate is remarkably increased, and the production period is shortened.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of germanium metallurgy and high-purity germanium material preparation, and in particular to a device and method for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen. Background Art

[0002] Metallic germanium is an important scarce strategic resource, widely used in many national defense military and civilian fields such as infrared optics, fiber optic communications, aerospace, solar cells, nuclear physics detection, chemical catalysts, etc., especially single crystal germanium, which is a key material supporting the development of the national economy and national defense construction, and belongs to my country's strategic reserve metals. High-purity germanium is an important raw material for growing single crystal germanium. It is obtained by reducing germanium dioxide with hydrogen at high temperature. The reaction formula is as follows:

[0003] GeO2+H2=GeO+H20

[0004] GeO+H2=Ge+H2O

[0005] At present, the process of hydrogen reduction of germanium dioxide mainly adopts the traditional horizontal tube furnace. When hydrogen and high-purity germanium dioxide powder react, the contact area is relatively small, especially in the reduction process, the high-purity germanium dioxide powder is loaded in the graphite boat. When the reaction occurs, hydrogen flows from the upper layer of the graphite boat and contacts the surface of the germanium dioxide powder to produce a reduction reaction, generating a germanium powder product layer. For further reduction, hydrogen must diffuse through the product layer. As the reaction proceeds, the germanium powder product layer formed after reduction adheres to the surface of the germanium dioxide powder. As the germanium powder product layer gradually thickens, the greater the obstacle to the diffusion of hydrogen into the germanium dioxide powder, which not only increases the reduction reaction time, prolongs the reduction cycle, and makes it difficult to improve production efficiency, but also causes a large amount of hydrogen consumption and waste, and increases costs (the schematic diagram of the traditional horizontal tube furnace hydrogen reduction process of germanium dioxide is as follows Figure 1 ). In addition, the current horizontal tube furnace reduction system also has the problem of uneven temperature, which leads to the intermediate product germanium monoxide in the reduction reaction. If the hydrogen supply participating in the reduction reaction is insufficient at this time, when the temperature exceeds 710°C, the germanium monoxide will not have time to be reduced to germanium powder and will directly sublimate and volatilize, resulting in the loss of germanium and the decrease of germanium recovery rate. Part of the volatilized germanium monoxide will adhere to the wall of the tube furnace and the gas pipeline, and the other part will be discharged with the tail gas, resulting in pollution of the reduction equipment and loss of raw materials. Due to the limitations of the horizontal tube furnace, quartz tube diameter and germanium dioxide powder density of the existing equipment, as the amount of germanium dioxide loaded in the graphite boat increases and thickens, the reduction efficiency will be greatly reduced.

[0006] At present, the main problems of the existing schemes are: large amount of hydrogen, insufficient contact with germanium dioxide powder, serious waste, low reduction efficiency, long production cycle, and reduced recovery rate of reduced product germanium due to volatilization of intermediate products. The existing Chinese patent with publication number CN115627371A discloses a cyclone purification system for reduction and purification of germanium dioxide. The germanium dioxide powder is fully contacted with hydrogen in the cyclone separation cylinder, which significantly improves the efficiency of reducing germanium dioxide powder to prepare germanium ingots and reduces the preparation cost; however, there are problems such as complex device structure, difficult to control temperature uniformity, and limited output. Summary of the invention

[0007] In view of this, the embodiment of the present application provides a device and method for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen, so that hydrogen directly enters the interior of the graphite crucible, fully contacts and reacts with germanium dioxide, and the unconsumed hydrogen refluxes under the obstruction of the gas guide cover and reacts with the germanium dioxide again, so that the hydrogen is fully utilized; at the same time, the germanium monoxide intermediate product generated during the reduction reaction is easy to volatilize, refluxes under the obstruction of the upper gas guide cover and continues to react with hydrogen, thereby reducing the loss of germanium; the present application greatly reduces the amount of hydrogen used in the production process of reducing germanium dioxide to prepare high-purity germanium powder, significantly improves the utilization rate of hydrogen, and shortens the reduction production cycle, thereby solving the problems of low efficiency, high cost, large germanium loss, and long reduction cycle in the prior art when using hydrogen to reduce high-purity germanium dioxide to prepare high-purity germanium powder.

[0008] A first aspect of an embodiment of the present application provides a device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen, the device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen comprising a furnace body, a furnace tube passing through the furnace body, both ends of the furnace tube extending outside the furnace body and being fixed by a furnace tube bracket, the furnace tube bracket being fixed on the furnace body; a graphite crucible assembly and a furnace plug are sequentially arranged in the furnace tube from bottom to top, and a gap exists between the graphite crucible assembly and the furnace plug.

[0009] In some embodiments that may include the above embodiments, the device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen also includes a hollow pillar, which is used to support the graphite crucible assembly and fix it in the furnace tube, and the hollow pillar is also used to introduce reaction gas into the graphite crucible assembly.

[0010] In some embodiments that may include the above embodiments, the graphite crucible assembly includes a graphite crucible, the graphite crucible is a cylindrical structure with openings at both ends, both ends of the graphite crucible are provided with gas guide covers, and the gas guide covers are provided with dense sieve-like through holes.

[0011] In some embodiments, which may include the above embodiments, the hollow pillar is disposed flush with the bottom of the graphite crucible.

[0012] In some embodiments that may include the above embodiments, the gas guide cover is provided with a protrusion toward the inside of the graphite crucible, the protrusion is adapted to the port of the graphite crucible, the protrusion is connected to the gas guide cover, and dense sieve-like through holes are also provided around the protrusion.

[0013] In some embodiments that may include the above embodiments, an external thread is further provided around the protruding portion, the graphite crucible port is provided with an internal thread matched with the external thread, and the protrusion and the graphite crucible are threadedly connected.

[0014] In some embodiments, which may include the above embodiments, the diameter of the through hole is less than 10 mm.

[0015] In some embodiments, which may include the above embodiments, the hollow struts are stainless steel struts.

[0016] In some embodiments that may include the above embodiments, the furnace tube is a quartz tube, and a vacuum gauge is also provided on the furnace body.

[0017] The second aspect of the embodiment of the present application further provides a method for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen, and the device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen includes the following steps:

[0018] Step 1, placing germanium dioxide powder in a graphite crucible, and covering both ends of the graphite crucible with gas guide covers, and then placing the covered graphite crucible into a device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen containing a hollow pillar;

[0019] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, the furnace is evacuated, and the air in the furnace is replaced with an inert gas;

[0020] Step 3: After the inert gas replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar, and the heating system of the device for reducing germanium dioxide with hydrogen to prepare high-purity germanium powder is turned on and the temperature is kept at a certain temperature to perform a reduction reaction;

[0021] Step 4: Pour the germanium powder obtained by reduction in step 3 out of the graphite crucible and collect it.

[0022] It should be noted that the present application is different from the conventional tubular furnace in which the reducing gas first enters the furnace tube and then penetrates into the crucible to react with the material, which effectively increases production capacity and improves production efficiency; the present application can adjust the reaction temperature, heating rate and hydrogen flow rate according to the weight of the reduced germanium dioxide powder; by controlling the reduction temperature, gas flow rate and other process parameters, the particle size of the high-purity germanium powder after reduction can be controlled.

[0023] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0024] 1. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen in the embodiment of the present application allows hydrogen to directly enter the graphite crucible and fully contact with germanium dioxide to undergo a reduction reaction, thereby ensuring that hydrogen is fully in contact with germanium dioxide, improving the reduction efficiency, and shortening the reduction production cycle. At the same time, due to the obstruction of the gas guide cover on the graphite crucible, the unreacted hydrogen is further fully utilized by reflux in the graphite crucible, greatly improving the utilization rate of hydrogen, and solving the problems of large hydrogen flow, serious waste, and high cost in the traditional industrial production of preparing germanium powder by reducing high-purity germanium dioxide with hydrogen;

[0025] 2. In the embodiment of the present application, the graphite crucible is cylindrical, and high-purity germanium dioxide is placed inside the graphite crucible. Hydrogen flows through the inside of the graphite crucible, fully contacts and reacts with the germanium dioxide, and the unconsumed hydrogen refluxes under the obstruction of the gas guide cover and reacts with the germanium dioxide again, so that the hydrogen is fully utilized; at the same time, the volatile intermediate product (germanium monoxide) produced in the reduction reaction is prevented from being directly discharged with the tail gas under the obstruction of the upper gas guide cover, and remains in the graphite crucible to continue to react with the hydrogen, thereby reducing the loss of the product germanium powder; in the production process of reducing germanium dioxide to prepare germanium powder, the use of hydrogen is greatly reduced, the reduction production cycle is shortened, the utilization efficiency of hydrogen is significantly improved, and the pollution and loss of equipment and high-purity germanium in the process of reducing high-purity germanium dioxide to prepare germanium powder by hydrogen are effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the process of reducing germanium dioxide with hydrogen in a traditional horizontal tube furnace;

[0028] Figure 2 Schematic diagram of gas flow dispersion in the furnace tube of the embodiment of the present application;

[0029] Figure 3 A cross-sectional view of a device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen in an embodiment of the present application;

[0030] Figure 4 A schematic diagram of the side structure of the gas guide cover according to an embodiment of the present application;

[0031] Figure 5A schematic diagram of the front structure of the gas guide cover according to an embodiment of the present application;

[0032] Figure 6 A sample of metal Ge powder prepared by reducing GeO2 with hydrogen in Example 2 of the present application;

[0033] Figure 7 XRD pattern of the metal Ge powder sample prepared by hydrogen reduction of GeO2 in Example 2 of the present application.

[0034] Description of reference numerals:

[0035] 1. Furnace tube; 2. Furnace tube bracket; 3. Graphite crucible; 4. Gas guide cover; 5. Furnace plug; 6. Hollow pillar; 7. Through hole. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. 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 this application.

[0037] Unless otherwise specified, the experimental methods used in the examples of this application are all conventional methods.

[0038] In the following examples, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.

[0039] Example 1

[0040] like Figure 2-5 As shown, an embodiment of the present application provides a device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen, comprising a furnace body, a furnace tube 1 is penetrated in the furnace body, both ends of the furnace tube 1 extend outside the furnace body and are fixed by furnace tube brackets 2, and the furnace tube brackets 2 are fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug 5 are sequentially arranged in the furnace tube 1 from bottom to top, a stainless steel pipe is connected to the air outlet at the upper end of the furnace tube 1, and the furnace plug 5 is threadedly fixedly connected to the stainless steel pipe to realize the fixation of the furnace plug 5 in the furnace tube 1, and there is a gap between the graphite crucible assembly and the furnace plug 5.

[0041] Furthermore, it also includes a hollow pillar 6, which is used to support the graphite crucible assembly to be fixed in the furnace tube 1, and the hollow pillar 6 is also used to introduce reaction gas into the graphite crucible assembly; illustratively, the hollow pillar 6 is a stainless steel pillar.

[0042] Specifically, the graphite crucible assembly includes a graphite crucible 3, which is a cylindrical structure with openings at both ends. The height of the graphite crucible 3 is adjusted according to the charge mass and the heating temperature zone of the tubular furnace, and is preferably 300 mm or 500 mm; gas guide covers 4 are provided at both ends of the graphite crucible 3, and dense sieve-like through holes 7 are provided on the gas guide covers 4.

[0043] Exemplarily, the hollow pillar 6 is arranged flush with the bottom of the graphite crucible 3 , which can effectively ensure that the hydrogen gas enters the graphite crucible 3 in a dispersed manner from the through holes 7 on the gas guide cover 4 at the bottom of the graphite crucible 3 .

[0044] Furthermore, the gas flow guide cover 4 is provided with a protrusion toward the inside of the graphite crucible 3, and the protrusion is adapted to the port of the graphite crucible 3. Preferably, the protrusion is cylindrical, and more preferably the height of the protrusion is 8-30 mm; the protrusion is connected to the gas flow guide cover 4, and dense sieve-like through holes 7 are also provided around the protrusion; illustratively, the diameter of the through holes 7 is less than 10 mm, preferably less than 5 mm, and more preferably less than 3 mm. The graphite crucible 3 acts as a loading container and a heating element during the smelting process. The design of the protrusion and the sieve-shaped through-hole gas guide cover enables the airflow entering the graphite crucible 3 to be dispersed in the graphite crucible 3 and fully react with the material. At the same time, the graphite crucible 3 can reflux the reaction gas passing through the graphite crucible 3, thereby prolonging the contact time between the gas and the material and reducing the waste of raw material gas. The volatile intermediate product germanium monoxide generated during the reaction will not be directly discharged with the tail gas under the obstruction of the upper gas guide cover 4, thereby effectively reducing the pollution of equipment and high-purity germanium and the loss of raw materials in the process of preparing germanium powder by reducing germanium dioxide with hydrogen.

[0045] Specifically, an external thread is provided around the protruding part, and an internal thread matching the external thread is provided at the port of the graphite crucible 3. The protrusion and the graphite crucible 3 are threadedly connected, which is convenient for disassembly and assembly for loading, unloading and other operations.

[0046] Furthermore, the furnace tube 1 is a quartz tube, and a vacuum gauge is also provided on the furnace body. The vacuum gauge is a prior art and will not be described in detail in this application.

[0047] In addition, the hollow pillar 6 and the graphite crucible assembly can be disassembled and replaced as the use time increases, which can effectively avoid equipment pollution and reduce equipment maintenance costs.

[0048] Example 2

[0049] The method for preparing high-purity germanium powder by reducing high-purity germanium dioxide with hydrogen in this embodiment adopts the device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen in Example 1, comprising the following steps:

[0050] Step 1: Place 10 g of GeO2 powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with gas guide covers, and then place the covered graphite crucible into a device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen containing a hollow pillar;

[0051] Step 2: Place the lower end of the graphite crucible horizontally on a hollow pillar, evacuate the furnace, and when the vacuum gauge of the furnace body shows less than 800 Pa, replace the air in the furnace with high-purity nitrogen, and circulate the replacement 5 times;

[0052] Step 3: After the high-purity nitrogen replacement in step 2 is completed, the reducing gas H2 is introduced at a flow rate of 50 ml / min, and the heating system of the hydrogen reduction germanium dioxide preparation high-purity germanium powder device (i.e., tubular furnace) is turned on at 10°C / min to reach the required temperature of 650°C for 90 minutes. When the germanium dioxide is completely reduced, the actual hydrogen usage is 4500 ml, which is 1.1 times the theoretical hydrogen usage under standard conditions;

[0053] Step 4: The germanium powder obtained by reduction in step 3 is taken out from the graphite crucible and collected, and high-purity germanium powder with required particle size can be obtained after vibration particle size screening. Figure 6 A sample of metal Ge powder prepared by reducing GeO2 with hydrogen in this embodiment; Figure 7 XRD pattern of the metal Ge powder sample prepared by hydrogen reduction of GeO2 in this example.

[0054] Example 3

[0055] The method for preparing high-purity germanium powder by reducing high-purity germanium dioxide with hydrogen in this embodiment adopts the device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen in Example 1, comprising the following steps:

[0056] Step 1: Place 3kg of GeO2 powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with gas guide covers, and then place the covered graphite crucible into a device for reducing germanium dioxide with hydrogen to prepare high-purity germanium powder containing a hollow pillar;

[0057] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow pillar, and the furnace is evacuated. When the vacuum gauge of the furnace body shows less than 800 Pa, high-purity nitrogen is used to replace the air in the furnace, and the replacement cycle is repeated 5 times;

[0058] Step 3: After the high-purity nitrogen replacement in step 2 is completed, the reducing gas H2 is introduced at a flow rate of 100L / h, and the heating system of the hydrogen reduction germanium dioxide preparation high-purity germanium powder device (i.e., tubular furnace) is turned on at 10°C / min to reach the required temperature of 650°C for reduction, and the temperature is kept for 15h. When the germanium dioxide is completely reduced, the actual hydrogen consumption is 1500L, which is 1.2 times the theoretically calculated hydrogen consumption under standard conditions;

[0059] Step 4: The germanium powder obtained by reduction in step 3 is taken out from the graphite crucible and collected, and high-purity germanium powder with required particle size can be obtained after vibration particle size screening.

[0060] Example 4

[0061] The method for preparing high-purity germanium powder by reducing high-purity germanium dioxide with hydrogen in this embodiment adopts the device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen in Example 1, comprising the following steps:

[0062] Step 1: Place 3kg of GeO2 powder to be reduced in a graphite crucible, cover both ends of the graphite crucible with gas guide covers, and then place the covered graphite crucible into a device for reducing germanium dioxide with hydrogen to prepare high-purity germanium powder containing a hollow pillar;

[0063] Step 2: The lower end of the graphite crucible is horizontally placed on a hollow pillar, and the furnace is evacuated. When the vacuum gauge of the furnace body shows less than 800 Pa, high-purity nitrogen is used to replace the air in the furnace, and the replacement cycle is repeated 5 times;

[0064] Step 3: After the high-purity nitrogen replacement in step 2 is completed, the reducing gas H2 is introduced at a flow rate of 100L / h, and the heating system of the hydrogen reduction germanium dioxide preparation high-purity germanium powder device (i.e., tubular furnace) is turned on at 10°C / min to reach the required temperature of 650°C for reduction, and the temperature is kept for 20h. When the germanium dioxide is completely reduced, the actual hydrogen consumption is 1500L, which is 1.2 times the theoretically calculated hydrogen consumption under standard conditions;

[0065] Step 4: The germanium powder obtained by reduction in step 3 is taken out from the graphite crucible and collected, and high-purity germanium powder with required particle size can be obtained after vibration particle size screening.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen, characterized in that: The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen comprises a furnace body, wherein a furnace tube is penetrated in the furnace body, and both ends of the furnace tube extend out of the furnace body and are fixed by a furnace tube bracket, wherein the furnace tube bracket is fixedly arranged on the furnace body; a graphite crucible assembly and a furnace plug are sequentially arranged in the furnace tube from bottom to top, and a gap exists between the graphite crucible assembly and the furnace plug.

2. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 1, characterized in that: The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen also includes a hollow support, which is used to support the graphite crucible assembly and fix it in the furnace tube, and is also used to introduce reaction gas into the graphite crucible assembly.

3. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 1, characterized in that: The graphite crucible assembly comprises a graphite crucible, which is a cylindrical structure with openings at both ends. Both ends of the graphite crucible are provided with gas guide covers, and the gas guide covers are provided with dense sieve-like through holes.

4. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 2, characterized in that: The hollow pillar is arranged flush with the bottom of the graphite crucible.

5. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 3, characterized in that: The gas guide cover is protruded toward the inside of the graphite crucible, the protrusion is matched with the port of the graphite crucible, the protrusion is connected with the gas guide cover, and dense sieve-like through holes are also arranged around the protrusion.

6. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 5, characterized in that: The protrusion is also provided with external threads around it, the port of the graphite crucible is provided with internal threads matching the external threads, and the protrusion and the graphite crucible are threadedly connected.

7. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 5, characterized in that: The diameter of the through hole is less than 10 mm.

8. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 2, characterized in that: The hollow support is a stainless steel support.

9. The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to claim 1, characterized in that: The furnace tube is a quartz tube, and a vacuum gauge is also arranged on the furnace body.

10. A method for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen, characterized in that: The device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen according to any one of claims 1 to 9 comprises the following steps: Step 1, placing germanium dioxide powder in a graphite crucible, and covering both ends of the graphite crucible with gas guide covers, and then placing the covered graphite crucible into a device for preparing high-purity germanium powder by reducing germanium dioxide with hydrogen containing a hollow pillar; Step 2: The lower end of the graphite crucible is horizontally placed on a hollow support, the furnace is evacuated, and the air in the furnace is replaced with an inert gas; Step 3: After the inert gas replacement in step 2 is completed, the reducing gas H2 is introduced into the graphite crucible through the hollow pillar, and the heating system of the device for reducing germanium dioxide with hydrogen to prepare high-purity germanium powder is turned on and the temperature is kept at a certain temperature to perform a reduction reaction; Step 4: Pour the germanium powder obtained by reduction in step 3 out of the graphite crucible and collect it.

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