Novel method for purifying crude germanium tetrachloride

Abstract

The invention provides a novel method for purifying crude germanium tetrachloride, which comprises the processes of first-stage low-temperature evaporation, second-stage medium-temperature evaporation, third-stage negative-pressure evaporation, recovery of germanium tetrachloride tailings and the like. In the staged evaporation process of first-stage low-temperature evaporation, second-stage medium-temperature evaporation and third-stage negative-pressure evaporation, low-boiling-point impurities (such as chlorine and other volatile impurities) in germanium tetrachloride can be effectively removed, germanium tetrachloride is separated and purified in different stages by gradually increasing the temperature and adjusting the pressure, and the purity of germanium tetrachloride is improved. Finally, germanium tetrachloride with the purity of 99.9% or above is obtained. According to the method, the introduction of chemical materials such as concentrated hydrochloric acid, chlorine and the like is avoided while the coarse germanium tetrachloride is fully and preliminarily purified, so that the safety and environmental risks are reduced; and the method has the remarkable advantages of good purification effect, environmental friendliness and the like.

Description

Technical Field

[0001] The invention relates to the technical field of material purification, and in particular to a novel method for purifying crude germanium tetrachloride. Background Art

[0002] The conventional production process of germanium includes chlorination distillation of germanium materials - chlorine re-distillation (or hydrochloric acid extraction) - distillation - hydrolysis - reduction - zone melting and other processes. Because the germanium raw materials are complex and the distillation process does not have the ability to finely remove impurities, the crude germanium tetrachloride produced by chlorination distillation of germanium materials generally contains a certain amount of arsenic and other impurities, and the purity of germanium tetrachloride is less than or equal to 99%; it must be initially purified to a purity greater than 99% before entering the distillation process for deep purification. At present, there are three main technical routes for the preliminary purification of crude germanium tetrachloride: Hydrochloric acid extraction method: Based on the characteristics that AsCl3 has a high solubility in concentrated hydrochloric acid, while GeCl4 has a low solubility in concentrated hydrochloric acid, mechanical stirring or high-speed mist elution is used to fully mix the primary germanium tetrachloride and hydrochloric acid, and arsenic is extracted into concentrated hydrochloric acid to purify germanium tetrachloride. The advantage is that the process is simple; the disadvantage is that the hydrochloric acid after extraction contains arsenic and germanium, and comprehensive recovery of germanium is required. In addition, concentrated hydrochloric acid is used in the process, and the waste acid is hazardous waste, which has high safety and environmental risks and high safety and environmental costs.

[0003] Chlorine-passing and re-distillation method: After mixing germanium tetrachloride and pure hydrochloric acid, chlorine is passed through and heated to above 100°C to distill out germanium tetrachloride in a boiling manner. The arsenic in the germanium tetrachloride is oxidized to a pentavalent state by chlorine and remains in the hydrochloric acid. Chlorine-passing and re-distillation is equivalent to a combined process of hydrochloric acid extraction and secondary boiling distillation to preliminarily remove impurities in crude germanium tetrachloride. The advantage is good purification effect; the disadvantage is that the re-distilled waste hydrochloric acid contains arsenic and germanium, and germanium needs to be comprehensively recovered. In addition, concentrated hydrochloric acid and chlorine are used in the process, and the waste acid is hazardous waste, which has high safety and environmental risks and high safety and environmental protection costs.

[0004] At present, the main emphasis of the initial purification technology of crude germanium tetrachloride is on the purification of germanium tetrachloride, and its significant disadvantages are the large amount of concentrated hydrochloric acid and chlorine gas, high cost, and great environmental pressure. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art, and the proposed new method for purifying crude germanium tetrachloride by low-temperature evaporation without boiling method is to achieve the above purpose. The present invention adopts the following technical scheme: a new method for purifying crude germanium tetrachloride, the specific steps of the method are as follows: S1: low-temperature evaporation, by heating and stirring the crude germanium tetrachloride put into the enamel kettle and passing dry air, the first-stage reactant 1 is germanium tetrachloride containing a small amount of chlorine and low-boiling impurities, which is mixed with other crude germanium tetrachloride raw materials and then returned to step S1 to continue the reaction; the first-stage reactant 2 is the residual germanium tetrachloride after the first-stage evaporation, which continues to remain in the enamel kettle; S2: Evaporation at medium temperature, stop stirring, heat the remaining germanium tetrachloride in the first stage and introduce dry air, evaporate and condense to obtain the second stage reactant 1, which is pure germanium tetrachloride with a purity of 99.9%; the second stage reactant 2 obtained is the remaining germanium tetrachloride evaporated in the second stage, which continues to remain in the enamel kettle; S3: Vacuum evaporation, restart stirring and then reduce the pressure and heat the remaining germanium tetrachloride in the second stage, further evaporate to obtain the third stage reactant 1, which is germanium tetrachloride containing very few high-boiling impurities, and mix it with other crude germanium tetrachloride raw materials and return to step S1 to continue the reaction; the obtained third stage reactant 2 is the germanium tetrachloride remaining after evaporation in the third stage, which continues to remain in the enamel kettle; S4: After the stirring and heating of the tail material are stopped and the temperature drops to a limited value, the residual germanium tetrachloride from the three-stage evaporation in step S3 is extracted from the enamel kettle and sent to a secondary distillation process for germanium recovery and impurity removal after enrichment.

[0006] Preferably, in step S1, the first stage of low-temperature evaporation is heated and the temperature is controlled at 60-70°C; when the volume of the germanium tetrachloride received in the first stage reaches 1-5% of the volume of the crude germanium tetrachloride input, the first stage of low-temperature evaporation is completed.

[0007] Preferably, in step S2, the second stage medium-temperature evaporation is heated and the temperature is controlled at 70-82°C; after the volume of germanium tetrachloride received in the second stage reaches 70%-80% of the volume of the crude germanium tetrachloride input, the second stage medium-temperature evaporation is completed; the purity of the germanium tetrachloride output in the second stage is greater than the purity of the germanium tetrachloride product, which is not less than 99.9%, and the arsenic content is not more than 1ug / g, and can be used as a product in the distillation process.

[0008] Preferably, in step S3, the pressure in the kettle is controlled to be less than 0.1 MPa by the three-stage negative pressure evaporation, and the temperature is controlled at 70-80° C.; after the volume of the germanium tetrachloride received in the three stages reaches 5%-10% of the volume of the crude germanium tetrachloride input, the three-stage negative pressure evaporation is completed.

[0009] Preferably, in step S4, the temperature in the enamel kettle drops below 30° C. and then the residual germanium tetrachloride from the three-stage evaporation is extracted.

[0010] Preferably, in step S4, the secondary distillation process is to regenerate and remove impurities from the residual germanium tetrachloride by repeatedly performing chlorination distillation after supplementing an oxidant.

[0011] Compared with the prior art, the present invention has the following beneficial effects: the present invention can effectively remove low-boiling-point impurities (such as chlorine and other volatile impurities) in germanium tetrachloride by performing multi-stage evaporation and volatilization of germanium tetrachloride under conditions lower than the boiling point of germanium tetrachloride, in a staged evaporation process of low-temperature evaporation in the first stage, medium-temperature evaporation in the second stage, and negative pressure evaporation in the third stage, and can separate and purify germanium tetrachloride in different stages by gradually increasing the temperature and adjusting the pressure, and finally obtain germanium tetrachloride with a purity of more than 99.9%.

[0012] Secondly, the temperature and pressure in each stage are precisely controlled (such as 60-70℃, 70-82℃, below 0.1 MPa), ensuring that the evaporation rate of germanium tetrachloride is smooth and controlled under conditions below the boiling point, and the separation from impurities is good. Impurities can be fully removed, thereby improving the purity and quality of germanium tetrachloride.

[0013] At the same time, the residual germanium tetrachloride (the part enriched with high boiling point impurities) after the three-stage evaporation is recovered and the germanium is recovered and enriched through a secondary distillation process, which further improves the resource utilization efficiency and reduces the waste of waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall process of the present invention. DETAILED DESCRIPTION

[0015] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments.

[0016] The present invention provides a novel method for purifying crude germanium tetrachloride, and the specific steps of the method are as follows: S1: low temperature evaporation, by heating and stirring the crude germanium tetrachloride put into the enamel kettle and passing dry air, the first stage reactant 1 is germanium tetrachloride containing a small amount of chlorine and low boiling point impurities, which is mixed with other crude germanium tetrachloride raw materials and then returned to step S1 to continue the reaction; the first stage reactant 2 is the residual germanium tetrachloride evaporated in the first stage, which continues to remain in the enamel kettle.

[0017] The crude germanium tetrachloride is put into an enamel kettle, heated and temperature-controlled, a stirring device is turned on, and dried air is slowly introduced into the crude germanium tetrachloride, so that the germanium tetrachloride evaporates or volatilizes under a condition below the boiling point, and the germanium tetrachloride gas is condensed through a condenser to obtain a first-stage germanium tetrachloride; after the amount of germanium tetrachloride received in the first stage reaches a certain proportion, the first-stage low-temperature evaporation is completed; the germanium tetrachloride evaporated in the first stage contains a small amount of chlorine and low-boiling-point impurities, which are mixed with other crude germanium tetrachloride raw materials and returned to step S1; the remaining germanium tetrachloride after the first-stage evaporation remains in the enamel kettle, and the impurities with lower boiling points are removed, so that the purity is improved.

[0018] S2: Evaporation at medium temperature. After stopping stirring, the remaining germanium tetrachloride in the first stage is heated and dry air is introduced. After evaporation, the second stage reactant 1 is condensed to obtain pure germanium tetrachloride with a purity of 99.9%. The second stage reactant 2 is the remaining germanium tetrachloride after evaporation in the second stage, which continues to remain in the enamel kettle.

[0019] The stirring device is turned off, the residual germanium tetrachloride obtained from the first-stage evaporation in step S1 is heated and the dried air is introduced into the germanium tetrachloride, so that the germanium tetrachloride continues to evaporate or volatilize under the condition of being lower than the boiling point, and the germanium tetrachloride gas is condensed by a condenser to obtain the second-stage pure germanium tetrachloride; after the amount of germanium tetrachloride received in the second stage reaches a certain proportion, the second-stage medium-temperature evaporation is completed; the germanium tetrachloride product obtained by distillation in the second stage is the final product of the method, the purity of which can be obtained to be more than 99.9%, and can be sent to the distillation system for deep purification; the residual germanium tetrachloride from the second-stage evaporation is left in the enamel kettle, and the impurities with high boiling points are enriched.

[0020] S3: Vacuum evaporation, restart stirring and then reduce the pressure and heat the remaining germanium tetrachloride in the second stage, further evaporate to obtain the third stage reactant one, which is germanium tetrachloride containing very few high boiling point impurities, and mix it with other crude germanium tetrachloride raw materials and return to step S1 to continue the reaction; the third stage reactant two obtained is the germanium tetrachloride remaining after evaporation in the third stage, which continues to remain in the enamel kettle.

[0021] The stirring device is turned on again, and the vacuum unit connected to the germanium tetrachloride receiving bottle is started to reduce the internal pressure of the germanium tetrachloride receiving bottle chain, the pipeline and the distillation kettle; the germanium tetrachloride of the residual germanium tetrachloride from the second-stage evaporation obtained in step S2 is continuously heated and heated, so that the germanium tetrachloride continues to evaporate or volatilize under the condition of being lower than the boiling point, and the germanium tetrachloride gas is condensed through a condenser to obtain the third-stage germanium tetrachloride, and after the amount of the germanium tetrachloride received in the third stage reaches a certain proportion, the third-stage low-temperature evaporation is completed; the germanium tetrachloride evaporated under the third-stage negative pressure contains a very small amount of high-boiling-point impurities, which are mixed with other crude germanium tetrachloride raw materials and returned to step S1; the residual germanium tetrachloride from the third-stage evaporation is left in the enamel kettle, and impurities such as high boiling points are further enriched.

[0022] S4: After the stirring and heating of the tail material are stopped and the temperature drops to a limited value, the residual germanium tetrachloride from the three-stage evaporation in step S3 is extracted from the enamel kettle and sent to a secondary distillation process for germanium recovery and impurity removal after enrichment.

[0023] Preferably, in step S1, the first stage of low-temperature evaporation is heated and the temperature is controlled at 60-70°C; when the volume of the germanium tetrachloride received in the first stage reaches 1-5% of the volume of the crude germanium tetrachloride input, the first stage of low-temperature evaporation is completed.

[0024] The boiling point of germanium tetrachloride is 84°C. The purpose of controlling this temperature is to evaporate below the boiling point of germanium tetrachloride to remove chlorine and low-boiling impurities; the purpose of stirring and introducing dry gas is to increase the evaporation rate; the volume of germanium tetrachloride received in the first stage is controlled to be 1-5% of the volume of the crude germanium tetrachloride input in order to evaporate as little germanium tetrachloride as possible while fully removing impurities.

[0025] Preferably, in step S2, the second stage medium-temperature evaporation is heated and the temperature is controlled at 70-82°C; after the volume of germanium tetrachloride received in the second stage reaches 70%-80% of the volume of the crude germanium tetrachloride input, the second stage medium-temperature evaporation is completed; the purity of the germanium tetrachloride output in the second stage is greater than the purity of the germanium tetrachloride product, which is not less than 99.9%, and the arsenic content is not more than 1ug / g, and can be used as a product in the distillation process.

[0026] The second stage is heated by medium-temperature evaporation and controlled at 70-82°C. The purpose of controlling this temperature is to evaporate below the boiling point of germanium tetrachloride. Compared with boiling distillation, it is more conducive to controlling and reducing the evaporation of high-boiling-point impurities; the purpose of introducing dry gas is to accelerate and control the evaporation rate of germanium tetrachloride; the purpose of controlling the volume of germanium tetrachloride received in the second stage to be 70%-80% of the volume of the crude germanium tetrachloride input is to evaporate as much qualified pure germanium tetrachloride product as possible while controlling the amount of high-boiling-point impurities introduced.

[0027] Preferably, in step S3, the pressure in the kettle is controlled to be less than 0.1 MPa by the three-stage negative pressure evaporation, and the temperature is controlled at 70-80° C.; after the volume of the germanium tetrachloride received in the three stages reaches 5%-10% of the volume of the crude germanium tetrachloride input, the three-stage negative pressure evaporation is completed.

[0028] The purpose of controlling the temperature at 70-80°C and the pressure in the kettle to less than 0.1Mpa is to accelerate the evaporation rate and control the introduction of high-boiling-point impurities in the form of negative pressure evaporation; the volume of germanium tetrachloride received in the third stage reaches 5%-10% of the volume of the crude germanium tetrachloride input, and the third stage is ended. This is to control the amount of residual germanium tetrachloride after the end of the third stage for enriching high-boiling-point impurities.

[0029] Preferably, in step S4, the temperature in the enamel kettle drops below 30° C. and then the residual germanium tetrachloride from the three-stage evaporation is extracted.

[0030] Preferably, in step S4, the secondary distillation process further refines germanium tetrachloride by increasing the temperature and reducing the pressure to remove high-boiling point impurities therein and improve the recovery rate of germanium.

[0031] Specific implementation one: One-stage low-temperature evaporation: Temperature: 62°C Objective: Remove low boiling point impurities; Receiving volume: up to 5% of the input volume; Two-stage medium temperature evaporation: Temperature: 75℃; Objective: To remove medium boiling impurities by further evaporation; Receiving volume: 70% of the input volume; Three-stage negative pressure evaporation: Temperature: 76°C Negative pressure: 0.09~0.1 MPa; Goal: Remove high boiling point impurities and further improve purity; Receiving volume: 5% to 10% of the input volume; Germanium tetrachloride tailings recovery: The temperature drops to 30°C, and the residual material from the third stage of evaporation is recovered and sent to secondary distillation for further purification; result: Germanium tetrachloride product purity: 99.98% Arsenic content: 0.2 μg / g Through multi-stage evaporation, impurities are gradually removed to achieve extremely high purity and low arsenic content.

[0032] Specific implementation 2: One-stage low-temperature evaporation: Temperature: 70℃; Objective: Remove low boiling point impurities; Receiving volume: up to 1% of the input volume; Two-stage medium temperature evaporation: Temperature: 80℃; Goal: Further remove impurities and improve purity; Receiving volume: 80% of the input volume; Three-stage negative pressure evaporation: Temperature: 76°C Negative pressure: 0.08~0.1 MPa; Objective: To further remove high boiling point impurities and refine germanium tetrachloride; Receiving volume: up to 10% of the input volume. ; Germanium tetrachloride tailings recovery: The temperature is lowered to 25°C, and tailings are recovered and distilled twice; result: Germanium tetrachloride product purity: 99.92%; Arsenic content: 0.7 μg / g; Compared with Example 1, the purity is slightly lower, but still reaches the high-purity product standard.

[0033] Specific implementation three: One-stage low-temperature evaporation: Temperature: 65℃; Objective: Remove low boiling point impurities; Receiving volume: up to 3% of the input volume; Two-stage medium temperature evaporation: Temperature: 78°C; Goal: Remove further impurities and improve purity; Receiving volume: 75% of the input volume; Three-stage negative pressure evaporation: Temperature: 79°C Negative pressure: 0.09~0.1 MPa; Goal: To further remove high boiling point impurities by evaporation; Receiving volume: up to 8% of the input volume; Germanium tetrachloride tailings recovery: The temperature is lowered to 25°C, and tailings are recovered and distilled twice; result: Germanium tetrachloride product purity: 99.96%; Arsenic content: 0.3 μg / g; Compared with Example 2, the purity is higher, the arsenic content is lower, and a better impurity removal effect is demonstrated.

[0034] Comparative analysis: Temperature setting: Example 1 uses a lower temperature (62°C for the first stage, 75°C for the second stage, and 76°C for the third stage), which has a better effect on removing low-boiling point impurities.

[0035] The temperatures of Examples 2 and 3 are slightly higher, 70° C. (first stage) and 80° C. (second stage), respectively. More impurities may evaporate during the evaporation process, but germanium tetrachloride can still be effectively separated.

[0036] Receiving volume: The receiving volume control of Example 1 is relatively strict, namely 5% (first stage), 70% (second stage) and 5-10% (third stage), so that the evaporated products in each stage can be finely separated.

[0037] The second-stage receiving volume of Example 2 is relatively large (80%), while the third-stage receiving volume is also 10%, which may result in that some impurities cannot be fully separated.

[0038] The received volume of Example 3 is close to that of Example 2, but the overall volume is slightly smaller, indicating a higher degree of refining.

[0039] Purity and Arsenic Content: The product of Example 1 has the highest purity (99.98%) and the lowest arsenic content (0.2 μg / g), demonstrating its superiority in removing impurities.

[0040] The purity of Example 3 is also very high (99.96%), and the arsenic content is 0.3 μg / g.

[0041] The purity of Example 2 is relatively low (99.92%) and the arsenic content is slightly higher (0.7 μg / g), indicating that this method is slightly inferior to the other two examples in terms of impurity removal.

[0042] Recycling and Reuse: In all embodiments, the tailings recovery process is refined, and secondary distillation is used to further remove impurities and recover germanium, thereby improving the resource utilization efficiency of the entire process.

[0043] Example 1 Using lower temperature and precise evaporation control can remove impurities to the greatest extent, and the final product has the highest purity and the lowest arsenic content, which is suitable for application scenarios requiring extremely high purity germanium tetrachloride.

[0044] Example 3 is relatively balanced in terms of evaporation conditions and impurity removal, providing good purity (99.96%) and low arsenic content (0.3 μg / g), and is a relatively ideal process.

[0045] Although Example 2 can also obtain a high-purity product, its purity and arsenic content are slightly inferior to those of the first two examples. It is suitable for some applications that do not have strict purity requirements as in Example 1.

[0046] in conclusion: 1. In the three embodiments, different temperature conditions were used for staged evaporation. In the first stage low-temperature evaporation process, the temperature was set between 62°C and 80°C, and the temperature in the second and third stages also fluctuated in the medium and low temperature range. The experimental results show that by adjusting the evaporation temperature, the purity of germanium tetrachloride is gradually improved, impurities with lower boiling points are removed, and the quality of the product is improved.

[0047] Example 1 Using lower temperature and precise evaporation control can remove impurities to the greatest extent, and the final product has the highest purity and the lowest arsenic content, which is suitable for application scenarios requiring extremely high purity germanium tetrachloride.

[0048] Example 3 is relatively balanced in terms of evaporation conditions and impurity removal, providing good purity (99.96%) and low arsenic content (0.3 μg / g), and is a relatively ideal process.

[0049] Although Example 2 can also obtain a high-purity product, its purity and arsenic content are slightly inferior to those of the first two examples. It is suitable for some applications that do not have strict purity requirements as in Example 1.

[0050] The three-stage evaporation (low-temperature evaporation, medium-temperature evaporation, and negative pressure evaporation) can effectively remove impurities in germanium tetrachloride. Impurities with different boiling points are gradually separated through the evaporation process in each stage, thus achieving the purification of germanium tetrachloride. In the three-stage process, as the evaporation goes deeper, impurities with higher boiling points are enriched, and finally germanium tetrachloride with higher purity is obtained.

[0051] In different embodiments, the purity of the final germanium tetrachloride product is 99.92% to 99.98%, and the arsenic content is controlled between 0.2 μg / g and 0.7 μg / g. A higher evaporation temperature and a proper vacuum evaporation process help to better remove impurities, especially harmful elements such as arsenic, thereby improving the purity of germanium tetrachloride.

[0052] The invention also has an obvious cleaning feature, does not use chemical materials such as hydrochloric acid and chlorine, and has significant environmental benefits.

[0053] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. A novel method for purifying crude germanium tetrachloride, characterized in that: The specific steps of the method are as follows: S1: low-temperature evaporation, by heating and stirring the crude germanium tetrachloride put into the enamel kettle and passing dry air, the first-stage reactant 1 is germanium tetrachloride containing a small amount of chlorine and low-boiling impurities, which is mixed with other crude germanium tetrachloride raw materials and then returned to step S1 to continue the reaction; the first-stage reactant 2 is the residual germanium tetrachloride after the first-stage evaporation, which continues to remain in the enamel kettle; S2: Evaporation at medium temperature, stop stirring, heat the remaining germanium tetrachloride in the first stage and introduce dry air, evaporate and condense to obtain the second stage reactant 1, which is pure germanium tetrachloride with a purity of 99.9%; the second stage reactant 2 obtained is the remaining germanium tetrachloride evaporated in the second stage, which continues to remain in the enamel kettle; S3: Vacuum evaporation, restart stirring and then reduce the pressure and heat the remaining germanium tetrachloride in the second stage, further evaporate to obtain the third stage reactant 1, which is germanium tetrachloride containing very few high-boiling impurities, and mix it with other crude germanium tetrachloride raw materials and return to step S1 to continue the reaction; the obtained third stage reactant 2 is the germanium tetrachloride remaining after evaporation in the third stage, which continues to remain in the enamel kettle; S4: After the stirring and heating of the tail material are stopped and the temperature drops to a limited value, the residual germanium tetrachloride from the three-stage evaporation in step S3 is extracted from the enamel kettle and sent to a secondary distillation process for germanium recovery and impurity removal after enrichment.

2. A novel method for purifying crude germanium tetrachloride as claimed in claim 1, characterized in that: In the step S1, the first stage of low-temperature evaporation is heated and the temperature is controlled at 60-70° C. When the volume of the germanium tetrachloride received in the first stage reaches 1-5% of the volume of the crude germanium tetrachloride input, the first stage of low-temperature evaporation is completed.

3. A novel method for purifying crude germanium tetrachloride as claimed in claim 1, characterized in that: In step S2, the second stage medium-temperature evaporation is heated and the temperature is controlled at 70-82° C.; after the volume of germanium tetrachloride received in the second stage reaches 70%-80% of the volume of the crude germanium tetrachloride input, the second stage medium-temperature evaporation is completed; the purity of the germanium tetrachloride output in the second stage is greater than the purity of the germanium tetrachloride product, which is not less than 99.9%, and the arsenic content is not more than 1 ug / g, and can be used as a product in the distillation process.

4. A novel method for purifying crude germanium tetrachloride as claimed in claim 1, characterized in that: In step S3, the pressure in the kettle is controlled to be less than 0.1 MPa by the three-stage negative pressure evaporation, and the temperature is controlled at 70-80° C.; after the volume of the germanium tetrachloride received in the three stages reaches 5%-10% of the volume of the crude germanium tetrachloride input, the three-stage negative pressure evaporation is completed.

5. A novel method for purifying crude germanium tetrachloride as claimed in claim 1, characterized in that: In step S4, after the temperature in the enamel kettle drops below 30° C., the remaining germanium tetrachloride evaporated in the third stage is extracted.

6. A novel method for purifying crude germanium tetrachloride as claimed in claim 1, characterized in that: In step S4, the secondary distillation process further refines germanium tetrachloride by increasing temperature and reducing pressure to remove high boiling point impurities therein and improve the recovery rate of germanium.

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