A short-process method for preparing high-purity germanium from germanium tetrachloride and treating tail gas by recycling

Abstract

The present invention discloses a short-process method for preparing high-purity germanium from germanium tetrachloride and treating tail gas in a cycle. The device for preparing high-purity germanium by short-process hydrogen reduction of germanium tetrachloride according to the present invention includes a gas storage tank, a high-purity germanium tetrachloride hydrogen reduction furnace, a reaction tail gas rectification system, and a germanium dichloride chlorination system. The method of the present invention is to use high-purity hydrogen to carry high-purity germanium tetrachloride into the reduction furnace for reaction to deposit germanium metal on germanium rods, and then perform zone melting purification according to purity requirements; the unreacted gas passes through the subsequent rectification and chlorination systems to obtain high-purity hydrogen and germanium tetrachloride again, realizing the treatment of tail gas in a cycle.

Description

Technical Field

[0001] The present invention application relates to the technical field of precious metals, and particularly relates to a short-process method for preparing high-purity germanium from germanium tetrachloride and a tail gas recycling treatment method. Background Art

[0002] Germanium is an important element and is widely used in the semiconductor and electrical engineering industries. For example, it is used as a material for manufacturing infrared detectors, optical fiber devices, electronic devices, solar cells, etc. Since germanium has a high refractive index and a large absorption coefficient near a wavelength of 1.55 μm, the proportion of thin germanium films used in photon and telecommunication applications has been steadily increasing. In addition, the application fields of germanium are constantly expanding due to its great application potential in, for example, lithium-ion batteries and solar cells. The increasing use of this element in various application fields has driven the demand for high-purity germanium.

[0003] Currently, there are several processes for producing germanium. Conventional methods for depositing germanium on a substrate include chemical vapor deposition (CVD) of digermane or germane and plasma-enhanced chemical vapor deposition (13.56 MHz) of germane. In these studies, germane or digermane diluted with hydrogen is used as a precursor. In addition, in many studies, germanium is prepared by the disproportionation of germanium diiodide (GeI2). The disadvantages of the above methods for preparing germanium are that germane and digermane are toxic and unstable, and iodine is a reactive element.

[0004] In the smelting method of "chlorination - hydrolysis - reduction", germanium dioxide (GeO2) is generated by the hydrolysis of germanium tetrachloride (GeCl4), and then high-purity germanium is obtained by reducing GeO2 with hydrogen and passing through the zone melting purification process. In the "chlorination - hydrolysis - reduction" method, the reduction to produce metallic germanium uses GeO2 as a raw material and is prepared by hydrogen reduction. The reduction of GeO2 with hydrogen to obtain metallic germanium is a distributed reaction. GeO2 will first be reduced to GeO and then to Ge. The reduction reactions are as follows:

[0005] GeO2 + H2 = GeO + H2O

[0006] GeO + H2 = Ge + H2O

[0007] When the temperature reaches 700 °C, GeO is volatile. Therefore, the reaction temperature is controlled at 600 °C - 650 °C. However, due to the too long hydrolysis process, which requires steps such as hydrolysis, filtration, cleaning, calcination, grinding, and screening, there are disadvantages such as easy introduction of impurities causing secondary pollution and excessive investment in equipment and facilities.

[0008] In 2015, A. V. Kadomtseva studied the addition of copper nanoparticles modified multi-walled carbon nanotubes during the hydrogenation of germanium tetrachloride for catalysis, and proposed the reaction mechanism of the catalytic reduction of germanium tetrachloride and hydrogen. In 2016, A. V. Vorotyntsev studied the hydrogen reduction kinetics of germanium tetrachloride in the presence of pyrolytic tungsten, and provided the reaction activation energy data for the hydrogen reduction of germanium tetrachloride and the activation energy data after adding the catalyst. In 2018, A. V. Kadomtseva discovered the presence of copper germanium through the comparative analysis of the preparation of germanium catalysts by the hydrogen reduction of germanium tetrachloride by using hybrid catalysts. In 2020, A. V. Kadomtseva developed a process for the hydrogen reduction of germanium tetrachloride with tungsten catalysis, which reduced the reaction temperature and the number of steps in the germanium preparation process. However, by-products are generated in the above discoveries and inventions, and the subsequent tail gas treatment problem has not been solved. Therefore, it is necessary to develop a green and environmentally friendly method for the short-process preparation of germanium by the hydrogen reduction of germanium tetrachloride with higher economic benefits. Summary of the Invention

[0009] To solve or partially solve the problems existing in the related technologies, the present invention application provides a method for the short-process preparation of high-purity germanium from germanium tetrachloride and the tail gas recycling treatment, so that the reaction is more stable, the possibility of introducing impurities during the reaction process is smaller, at the same time, the lengthy step of hydrolyzing germanium tetrachloride to germanium dichloride is omitted, the investment in equipment costs is reduced, the by-products can be reused after treatment, the costs are saved, and the economic benefits are improved.

[0010] The present invention application provides a method for the short-process preparation of high-purity germanium from germanium tetrachloride and the tail gas recycling treatment, including the following steps:

[0011] S1. By controlling the flow rate of high-purity hydrogen, the high-purity germanium tetrachloride vapor is introduced into the high-purity germanium tetrachloride hydrogen reduction furnace. The reaction temperature is controlled by a controller to deposit metal germanium particles on the germanium pair rods. The metal germanium particles on the germanium pair rods are collected and purified by zone melting to obtain high-purity metallic germanium;

[0012] Specifically, the following reaction occurs between germanium tetrachloride and hydrogen in the reduction furnace:

[0013] GeCl4 + 2H2 = Ge + 4HCl

[0014] S2. After the reaction is completed, the unreacted germanium tetrachloride and hydrogen, the hydrogen chloride generated by the reaction, and the by-product germanium dichloride are separated by rectification through the reaction tail gas rectification system. Among them, germanium tetrachloride and hydrogen are sent back to the reduction furnace again after rectification separation. The hydrogen chloride is treated with pure water, and the by-product germanium dichloride reacts with chlorine provided by the chlorine storage tank through the germanium dichloride chlorination system to be chlorinated into germanium tetrachloride.

[0015] Furthermore, the inlet ratio of the high-purity hydrogen to the high-purity germanium tetrachloride vapor is controlled at 10-30.

[0016] Furthermore, the reaction temperature range of the high-purity germanium tetrachloride hydrogen reduction furnace is controlled at 700-900°C.

[0017] Furthermore, after the reduction reaction is completed, the germanium tetrachloride, hydrogen, hydrogen chloride and germanium dichloride are cooled by the water cooling system of the reduction furnace and then transported to the reaction tail gas distillation system.

[0018] Furthermore, the germanium tetrachloride and hydrogen in the tail gas are respectively distilled to reach the purity of germanium tetrachloride and hydrogen when fed, and then transported to the germanium tetrachloride hydrogen reduction furnace or to the germanium tetrachloride gas storage tank and the hydrogen gas storage tank respectively.

[0019] Furthermore, the germanium dichloride in the tail gas is distilled and sent to the germanium dichloride chlorination system, and the ratio of chlorine provided by the chlorine storage tank to germanium dichloride inlet gas is controlled between 1 and 10, and a reaction occurs to generate germanium tetrachloride through chlorination.

[0020] Specifically, the following reactions occur:

[0021] GeCl2+Cl2=GeCl4

[0022] Furthermore, the gas chlorinated by the germanium dichloride chlorination system returns to the reactive distillation system again, and the germanium tetrachloride therein is transported to the germanium tetrachloride gas storage tank after reaching the required purity through multiple distillations, and the incompletely chlorinated germanium dichloride and chlorine are sent to the germanium dichloride chlorination system for further treatment.

[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention.

[0024] Beneficial technical effects of the present invention:

[0025] The invention introduces only germanium, hydrogen and chlorine as the elements in the short-process preparation of high-purity germanium by germanium tetrachloride and the tail gas recycling treatment method. Compared with other germanium preparation methods, it is not easy to introduce other impurities to cause pollution, thereby improving the purity of the obtained metallic germanium.

[0026] Compared with the method using digermane or germane, the reaction of the present invention is more stable. Compared with the "chlorination-hydrolysis-reduction" smelting method, the process of preparing germanium from germanium tetrachloride is optimized, the lengthy step of hydrolysis to germanium dichloride is omitted, and the investment of equipment cost is reduced.

[0027] The byproduct germanium dichloride obtained in the process of the reaction of germanium tetrachloride and hydrogen is separated and rectified and then treated by a chlorination system to become the reactant germanium tetrachloride. The method allows the byproduct to be reused, saves costs, and improves economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a process flow diagram of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The optional embodiments of the present invention application will be described in more detail below with reference to the accompanying drawings. Although the optional embodiments of the present invention application are shown in the drawings, it should be understood that the present invention application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention application more thorough and complete, and to fully convey the scope of the present invention application to those skilled in the art.

[0030] The terms used in the present invention application are only for the purpose of describing specific embodiments and are not intended to limit the present invention application. The singular forms "a", "the" and "said" used in the present invention application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0031] The method for preparing high-purity germanium and treating tail gas circulation in a short process of germanium tetrachloride of the present invention application will be described in detail below with reference to the accompanying drawings, as follows:

[0032] For clearer illustration, the following examples are used for detailed description.

[0033] Example 1

[0034] The flow rate of high-purity hydrogen is controlled by a flow meter, and the ratio of high-purity germanium tetrachloride vapor obtained by multiple rectifications upstream to high-purity hydrogen is 1:15, which is introduced into a high-purity germanium tetrachloride hydrogen reduction furnace. The reaction temperature is controlled at 800 °C by a controller, and the gas is continuously introduced for 8 hours. Metal germanium particles are deposited on the germanium pair rods, and the metal germanium particles on the germanium pair rods are collected and purified by zone melting to obtain high-purity metal germanium; after the reaction, the unreacted germanium tetrachloride hydrogen, the hydrogen chloride generated by the reaction and the by-product germanium dichloride are separated by multiple rectifications through a reaction tail gas rectification system. Among them, germanium tetrachloride and hydrogen are sent back to the reduction furnace again after rectification separation; hydrogen chloride is treated with pure water; the by-product germanium dichloride reacts with chlorine through a germanium dichloride chlorination system, and the ratio of chlorine to germanium dichloride is 2:1, and it is chlorinated to germanium tetrachloride. It is measured that the primary conversion rate of preparing germanium by the short process of germanium tetrachloride hydrogen reduction is 23.82%.

[0035] Example 2

[0036] The flow rate of high-purity hydrogen is controlled by a flowmeter. High-purity germanium tetrachloride vapor obtained by multiple rectifications upstream and high-purity hydrogen with a ratio of 1:20 are introduced into a high-purity germanium tetrachloride hydrogen reduction furnace. The reaction temperature is controlled at 850 °C by a controller, and the gas is continuously introduced for 8 hours. Metal germanium particles are deposited on the germanium pair rods. The metal germanium particles on the germanium pair rods are collected and high-purity metal germanium is obtained through zone melting purification. After the reaction, the unreacted germanium tetrachloride hydrogen, the hydrogen chloride generated by the reaction, and the by-product germanium dichloride are subjected to multiple rectification separations through a reaction tail gas rectification system. Among them, germanium tetrachloride and hydrogen are sent back to the reduction furnace again after rectification separation. Hydrogen chloride is treated with pure water. The by-product germanium dichloride reacts with chlorine through a germanium dichloride chlorination system, and the ratio of chlorine to germanium dichloride is 1:1, and it is chlorinated to germanium tetrachloride. It is measured that the primary conversion rate of preparing germanium by the short process of germanium tetrachloride hydrogen reduction is 28.32%.

[0037] Example 3

[0038] The flow rate of high-purity hydrogen is controlled by a flowmeter. High-purity germanium tetrachloride vapor obtained by multiple rectifications upstream and high-purity hydrogen with a ratio of 1:20 are introduced into a high-purity germanium tetrachloride hydrogen reduction furnace. The reaction temperature is controlled at 875 °C by a controller, and the gas is continuously introduced for 10 hours. Metal germanium particles are deposited on the germanium pair rods. The metal germanium particles on the germanium pair rods are collected and high-purity metal germanium is obtained through zone melting purification. After the reaction, the unreacted germanium tetrachloride hydrogen, the hydrogen chloride generated by the reaction, and the by-product germanium dichloride are subjected to multiple rectification separations through a reaction tail gas rectification system. Among them, germanium tetrachloride and hydrogen are sent back to the reduction furnace again after rectification separation. Hydrogen chloride is treated with pure water. The by-product germanium dichloride reacts with chlorine through a germanium dichloride chlorination system, and the ratio of chlorine to germanium dichloride is 2:1, and it is chlorinated to germanium tetrachloride. It is measured that the primary conversion rate of preparing germanium by the short process of germanium tetrachloride hydrogen reduction is 28.44%.

[0039] Example 4

[0040] The flow rate of high-purity hydrogen is controlled by a control flow meter. High-purity germanium tetrachloride vapor obtained by multiple rectifications upstream and high-purity hydrogen with a ratio of 1:25 are introduced into a high-purity germanium tetrachloride hydrogen reduction furnace. The reaction temperature is controlled at 875 °C by a controller, and the gas is continuously introduced for 10 hours. Metal germanium particles are deposited on the germanium pair rods. The metal germanium particles on the germanium pair rods are collected and purified by zone melting to obtain high-purity metallic germanium. After the reaction, unreacted germanium tetrachloride hydrogen and hydrogen chloride generated by the reaction, as well as by-product germanium dichloride, are subjected to multiple rectification separations through a reaction tail gas rectification system. Among them, germanium tetrachloride and hydrogen are sent back to the reduction furnace again after rectification separation; hydrogen chloride is treated with pure water; the by-product germanium dichloride reacts with chlorine through a germanium dichloride chlorination system, and the ratio of chlorine to germanium dichloride is 5:1, and it is chlorinated to germanium tetrachloride. It is measured that the primary conversion rate of preparing germanium by the short process of germanium tetrachloride hydrogen reduction is 31.82%.

[0041] The embodiments of the present invention application have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the embodiments disclosed herein.

Claims

1. A short-process method for preparing high-purity germanium from germanium tetrachloride and treating tail gas for recycling, characterized in that: The following steps are involved: S1. By controlling the flow rate of high-purity hydrogen, high-purity germanium tetrachloride vapor is brought into a high-purity germanium tetrachloride hydrogen reduction furnace, the reaction temperature is controlled by a controller to deposit metal germanium particles on the germanium rod pair, the metal germanium particles on the germanium rod pair are collected and purified by zone melting to obtain high-purity metal germanium; S2, the reaction is completed after the incomplete reaction of germanium tetrachloride and hydrogen, the hydrogen chloride produced by the reaction and the by-product germanium dichloride are separated by rectification by a reaction tail gas rectification system, wherein germanium tetrachloride and hydrogen are sent to a reduction furnace again after being separated by rectification, hydrogen chloride is processed by pure water, and the by-product germanium dichloride reacts with the chlorine provided by the germanium dichloride chlorination system and the chlorine storage tank, and chlorination is germanium tetrachloride; After the reduction reaction is completed, germanium tetrachloride, hydrogen, hydrogen chloride and germanium dichloride are cooled by the water cooling system of the reduction furnace and then transported to the reaction tail gas distillation system; The germanium tetrachloride and hydrogen in the tail gas are respectively distilled to reach the purity of germanium tetrachloride and hydrogen at the time of feeding, and then transported to the germanium tetrachloride hydrogen reduction furnace or to the germanium tetrachloride gas storage tank and hydrogen gas storage tank respectively; The germanium dichloride in the tail gas is distilled and sent to the germanium dichloride chlorination system. The ratio of chlorine gas provided by the chlorine storage tank to germanium dichloride inlet gas is controlled between 1 and 10, and a reaction occurs to generate germanium tetrachloride through chlorination. The gas chlorinated by the germanium dichloride chlorination system returns to the reactive distillation system again, and the germanium tetrachloride therein is transported to the germanium tetrachloride gas storage tank after multiple distillations to reach the required purity. The incompletely chlorinated germanium dichloride and chlorine are sent to the germanium dichloride chlorination system for further treatment.

2. The method for preparing high-purity germanium through a short process of germanium tetrachloride and treating tail gas by circulation according to claim 1, wherein: The inlet ratio of high-purity hydrogen to high-purity germanium tetrachloride steam is controlled at 10-30.

3. The method for preparing high-purity germanium and treating tail gas recycling in a short process of germanium tetrachloride according to claim 1, wherein: The reaction temperature range of the high-purity germanium tetrachloride hydrogen reduction furnace is controlled at 700-900°C.

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