Method and device for removing arsenic from germanium tetrachloride by hydrogen peroxide oxidation

Abstract

The present application belongs to the technical field of rare metal metallurgy, and particularly relates to a method and device for removing arsenic in germanium tetrachloride by hydrogen peroxide oxidation. The arsenic removal device comprises GeCl4, H2O2 and HCl storage containers, the storage containers are connected with a first reactor and a second reactor through pipelines, fourth, fifth, sixth, seventh and eighth valves are arranged on the pipelines, a first constant temperature heater is arranged at the lower part of the first reactor, a first mechanical stirrer is arranged at the top of the first reactor, a first residual liquid collector is connected with the bottom of the first reactor through a pipeline, and ninth and eleventh valves are arranged between the first reactor and the first residual liquid collector. Compared with the traditional chlorine arsenic removal method, the present application uses hydrogen peroxide to remove arsenic in germanium tetrachloride, is more environmentally friendly, safe, low-cost and does not bring new impurity elements, and the arsenic removal effect is very significant.

Description

Technical Field

[0001] This invention belongs to the field of rare metal metallurgy technology, specifically relating to a method and apparatus for removing arsenic by hydrogen peroxide oxidation during the preparation of high-purity germanium tetrachloride materials. Background Technology

[0002] In the end-use consumption structure of germanium materials, the proportion of germanium used in optical fiber has been gradually increasing, reaching 34% in 2019, ranking second only to infrared optics. With China's rise and the needs of great power competition and national security, optical fibers used in special fields such as military and submarine cables have higher quality requirements. In the production process of high-purity germanium tetrachloride for optical fibers, arsenic is a very difficult-to-remove harmful impurity element, and its mass fraction needs to be reduced to 1×10⁻⁶. -5 Below 5%. Since the raw materials for preparing GeCl4 and GeO2 are mostly germanium concentrates with high arsenic content (As content between 1% and 5%), controlling the arsenic content during preparation has a significant impact on the quality of the final product.

[0003] Application No. "200910233353.5" entitled "Method for Arsenic Removal in the Distillation Process of Germanium Extraction" discloses a method for removing arsenic during the distillation process of germanium extraction by introducing chlorine gas at a rate of 0.5 to 50 liters and manganese dioxide in a weight ratio of 1:5 to 50 with arsenic. The arsenic-containing raw material and a certain proportion of manganese dioxide are added to a distillation vessel, hydrochloric acid is added, and chlorine gas is introduced for 15 to 30 minutes. The mixture is stirred, heated with steam, and germanium tetrachloride is distilled off.

[0004] Application number "201010553861.4" entitled "A Process for Improving the Recovery Rate of Crude Germanium Dioxide by Chlorination Distillation" describes a method for recovering germanium by oxidizing crude germanium with sodium chlorate to remove arsenic followed by hydrochloric acid chlorination distillation. Sodium hydroxide and sodium chlorate are used to convert trivalent arsenic to pentavalent arsenic, and finally, germanium tetrachloride is purified by distillation, resulting in a germanium tetrachloride solution with an arsenic content of less than 1×10⁻⁶. -4 %.

[0005] Yuan Qin et al. used germanium concentrate with an arsenic content of less than 6% as raw material. During the preparation of germanium tetrachloride, they added a certain concentration of hydrochloric acid, manganese dioxide, and ferric chloride. After heating, the arsenic was converted into high-boiling-point arsenic compounds. Most of the arsenic remained in the distillation vessel, while a portion was distilled off along with the germanium tetrachloride, thus reducing the arsenic content to 1×10⁻⁶. -4 %the following.

[0006] Traditional chlorine-based arsenic removal methods are problematic because chlorine is highly toxic and poses significant risks to the environment and human health; they also require large quantities and have low economic efficiency. Furthermore, using oxides such as sodium chlorate, manganese dioxide, and ferric oxide to oxidize trivalent arsenic introduces other impurities, significantly impacting the purity of the germanium tetrachloride product. Therefore, a more environmentally friendly, safe, and low-cost method that does not introduce new impurities and achieves arsenic removal results that meet production requirements is lacking. Summary of the Invention

[0007] The purpose of this invention is to provide a method and apparatus for separating and removing arsenic from germanium tetrachloride using hydrogen peroxide. The method involves oxidizing trivalent arsenic impurities in germanium tetrachloride to pentavalent arsenic impurities in a hydrochloric acid solution, followed by hydrochloric acid extraction to leave the arsenic impurities in the hydrochloric acid solution. After settling and separation, a large amount of arsenic is separated from germanium tetrachloride. This method and apparatus can obtain germanium tetrachloride with a purity of 5N or higher. Furthermore, this invention uses hydrogen peroxide to remove arsenic from germanium tetrachloride, making it more environmentally friendly, safer, lower cost, and without introducing new impurity elements. The arsenic removal effect is very significant.

[0008] The method's principle and the chemical reaction equation are as follows:

[0009] AsCl3 + 2HCl + H2O2 = AsCl5 + 2H2O

[0010] Meanwhile, since the boiling point of AsCl3 is 130.2℃ and the boiling point of GeCl4 is 84℃, their boiling points are close, making it difficult to remove arsenic impurities by distillation. However, the boiling point of AsCl5 is 275.6℃. By using H2O2 to oxidize AsCl3 to AsCl5, the trace amount of pentavalent arsenic remaining in germanium tetrachloride can be distilled and purified by subsequent hydrochloric acid distillation and rectification, while the pentavalent arsenic remains in the hydrochloric acid solution after distillation. This achieves the separation of germanium tetrachloride and arsenic, thereby improving the purity of germanium tetrachloride.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] A method for removing arsenic from germanium tetrachloride by hydrogen peroxide includes an arsenic removal device comprising GeCl4, H2O2, and HCl storage containers. The storage containers are connected to a first reactor and a second reactor via pipelines, and are equipped with a fourth, fifth, sixth, seventh, and eighth valve. A first constant-temperature heater is installed at the bottom of the first reactor, and a first mechanical stirrer is installed at the top. A first residual liquid collector is connected to the bottom via a pipeline. A ninth and eleventh valve are installed between the first reactor and the first residual liquid collector.

[0013] The second reactor is equipped with a second constant temperature heater at the bottom, a second mechanical stirrer at the top, and a distiller connected to the bottom via a pipe. A tenth valve and a twelfth valve are installed on the pipe. The distiller is equipped with a third constant temperature heater at the bottom and is connected to a second residual liquid collector 28 via a pipe. A thirteenth valve is installed on the pipe.

[0014] The ninth and eleventh valves are connected to the tenth and twelfth valves by a connecting pipe, which is connected to the first condenser. The first condenser is connected to the distillation column by a pipe.

[0015] The top of the distillation column is connected to a second condenser and a germanium tetrachloride collector in sequence via pipes. The bottom is equipped with a fourth constant temperature heater. The bottom is connected to a second residual liquid collector via pipes, and a twenty-ninth valve is installed on the pipes.

[0016] Arsenic removal methods include the following steps:

[0017] S1: Take crude germanium tetrachloride and determine the arsenic content in the crude germanium tetrachloride solution using potassium bromate titration.

[0018] S2: Calculate the molar mass of arsenic based on the measured arsenic content and the total amount of GeCl4 added. The molar ratio of As to H2O2 is 1:1 to 20. Calculate the volume of H2O2. The volume ratio of HCl to H2O2 is 1:1.1 to 10. Calculate the amount of HCl based on the volume of H2O2.

[0019] S3: Open the fourth, fifth, sixth, and seventh valves to introduce a measured amount of GeCl4, 30% H2O2 solution, and 37% HCl solution into the first reactor, and then close the valves;

[0020] S4: Start the first constant temperature heater and heat to a temperature <48℃. Then turn on the first mechanical stirrer and stir and oxidize for 45 min to 120 min. The stirring rate is 60 r / min to 180 r / min. Turn off the first mechanical stirrer and let the liquid in the first reactor stand for a period of time before separating the liquid.

[0021] S5: Open valves 9 and 10 to transfer the initially extracted germanium tetrachloride from the lower layer to the second reactor, then close the valves;

[0022] S6: Open valves 9 and 11 to discharge the remaining waste liquid in the first reactor into the first residual liquid collector, and then close the valves;

[0023] S7: Open valves 5, 6 and 8, add the amounts of H2O2 and HCl determined in step S2 to the second reactor, and then close the valves;

[0024] S8: Turn on the second constant temperature heater and heat to a temperature <48℃. Then turn on the second mechanical stirrer and stir at a speed of 60 r / min to 180 r / min for 45 min to 120 min. Further oxidize germanium tetrachloride to remove arsenic after the first arsenic removal. After the oxidative extraction is complete, let it stand for a period of time and then separate the liquids.

[0025] S9: Open valves 10 and 12 to transfer the germanium tetrachloride extracted in the second extraction below into the distiller, and then close the valves;

[0026] S10: Open the tenth and eleventh valves to discharge the remaining waste liquid into the first residual liquid collector, and then close the valves;

[0027] S11: Open the twelfth valve and the third constant temperature heater, heat to 90℃~100℃ to perform preliminary distillation of germanium tetrachloride after oxidative extraction, and liquefy and condense it in the first condenser to the distillation column; then close the valve;

[0028] S12: Open the thirteenth valve to transfer the remaining liquid in the distiller to the second residual liquid collector;

[0029] S13: Turn on the fourth constant temperature heater and heat to 90℃~100℃ to further distill the germanium tetrachloride after preliminary distillation. The vaporized germanium tetrachloride is liquefied and collected in the germanium tetrachloride collector through the second condenser.

[0030] S14: Open the twenty-ninth valve to discharge the remaining liquid into the second residual liquid collector.

[0031] Preferably, in steps S4 and S8, the heating temperature is 20°C to 40°C.

[0032] Preferably, in steps S4 and S8, the settling time is 30 min to 45 min.

[0033] The advantages of this invention are:

[0034] Traditional chlorine-based arsenic removal methods consume large quantities of chlorine, resulting in high costs. Furthermore, chlorine is highly toxic, posing significant risks to the environment and the health of operators. Hydrogen peroxide, on the other hand, is non-toxic and harmless, and can remove arsenic levels to below the required concentrations in small quantities, causing minimal harm and without introducing new impurities. Attached Figure Description

[0035] Figure 1 This is a flowchart of the arsenic removal process.

[0036] Figure 2 This is a schematic diagram of an arsenic removal device;

[0037] Among them, 1. GeCl4 storage container; 2. H2O2 storage container; 3. HCl storage container; 4. Fourth valve; 5. Fifth valve; 6. Sixth valve; 7. Seventh valve; 8. Eighth valve; 9. Ninth valve; 10. Tenth valve; 11. Eleventh valve; 12. Twelfth valve; 13. Thirteenth valve; 29. ​​Twenty-ninth valve; 14. First constant temperature heater; 15. Second constant temperature heater; 16. Third constant temperature heater; 17. Fourth constant temperature heater; 18. First reactor; 19. Second reactor; 20. First residual liquid collector; 28. Second residual liquid collector; 21. First mechanical stirrer; 22. Second mechanical stirrer; 23. Distillation apparatus; 24. First condenser; 26. Second condenser; 25. Distillation column; 27. Germanium tetrachloride collector. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] refer to Figure 2 The arsenic removal device includes a GeCl4 storage container 1, an H2O2 storage container 2, and an HCl storage container 3. The storage containers are connected to a first reactor 18 and a second reactor 19 via pipes, and are equipped with a fourth valve 4, a fifth valve 5, a sixth valve 6, a seventh valve 7, and an eighth valve 8. A first constant temperature heater 14 is installed at the bottom of the first reactor 18, and a first mechanical stirrer 21 is installed at the top. A first residual liquid collector 20 is connected to the bottom via a pipe. A ninth valve 9 and an eleventh valve 11 are installed between the first reactor 18 and the first residual liquid collector 20.

[0041] The second reactor 19 is equipped with a second constant temperature heater 15 at the bottom, a second mechanical stirrer 22 at the top, and a distiller 23 at the bottom via a pipe. A tenth valve 10 and a twelfth valve 12 are installed on the pipe. A third constant temperature heater 16 is installed at the bottom of the distiller 23. The bottom of the distiller 23 is connected to a second residual liquid collector 28 via a pipe, and a thirteenth valve 13 is installed on the pipe.

[0042] A connecting pipe is provided between the ninth valve 9 and the eleventh valve 11 and the tenth valve 10 and the twelfth valve 12, which is connected to the first condenser 24. The first condenser 24 is connected to the distillation column 25 through a pipe.

[0043] The top of the distillation column 25 is connected to the second condenser 26 and the germanium tetrachloride collector 27 in sequence through pipes. The lower part is equipped with the fourth constant temperature heater 17. The bottom is connected to the second residual liquid collector 28 through pipes, and the twenty-ninth valve 29 is installed on the pipes.

[0044] Example 2

[0045] refer to Figure 1 , Figure 2 The arsenic removal method includes the following steps:

[0046] S1: Take crude germanium tetrachloride and determine the arsenic content in the crude germanium tetrachloride solution using potassium bromate titration.

[0047] S2: Calculate the molar mass of arsenic based on the measured arsenic content and the total amount of GeCl4 added. The molar ratio of As to H2O2 is 1:1 to 20. Calculate the volume of H2O2 based on this molar ratio. The volume ratio of HCl to H2O2 is 1:1.1 to 10. Calculate the amount of HCl based on the volume of H2O2, as follows:

[0048] Y = X / 75g / mol × AY:Z = 1:1 to 20

[0049] B = Z / 0.98 mol / L : C = 1:1.1–10

[0050] Where X is the arsenic content (g / L), Y is the molar mass of arsenic, Z is the molar mass of H2O2, A is the volume of germanium tetrachloride, B is the volume of H2O2, and C is the volume of HCl;

[0051] S3: Open valves 4, 5, 6, and 7 to introduce a measured amount of GeCl4, 30% H2O2 solution, and 37% HCl solution into the first reactor 18, and then close the valves;

[0052] S4: Start the first constant temperature heater 14 and heat at a temperature of 20℃~40℃. Then turn on the first mechanical stirrer 21 and stir and oxidize for 45 min~120 min. The stirring rate is 60 r / min~180 r / min. Turn off the first mechanical stirrer 21 and let the liquid in the first reactor 18 stand for a period of time of 30 min~45 min before separating the liquid.

[0053] S5: Open valves 9 and 10 to transfer the initially extracted germanium tetrachloride from the lower layer to the second reactor 19, and then close the valves;

[0054] S6: Open valves 9 and 11 to discharge the remaining waste liquid in the first reactor 18 into the first residual liquid collector 20, and then close the valves;

[0055] S7: Open valves 5, 6 and 8, add the same amount of H2O2 and HCl as determined in S2 into the second reactor 19, and then close the valves;

[0056] S8: Turn on the second constant temperature heater 15 and heat at a temperature of 20℃~40℃. Then turn on the second mechanical stirrer 22 and stir at a speed of 60 r / min~180 r / min. Stir and oxidize for 45 min~120 min. Further oxidize germanium tetrachloride to remove arsenic after the first arsenic removal. After the oxidation extraction is complete, let it stand for 30 min~45 min and then separate the liquid.

[0057] S9: Open the tenth valve 10 and the twelfth valve 12 to transfer the germanium tetrachloride extracted in the second extraction below into the distiller 23, and then close the valves;

[0058] S10: Open the tenth valve 10 and the eleventh valve 11 to discharge the remaining waste liquid into the first residual liquid collector 20, and then close the valves;

[0059] S11: Open the twelfth valve 12 and the third constant temperature heater 16, heat to 90℃~100℃ to perform preliminary distillation on germanium tetrachloride that has been oxidized and extracted, and liquefy and condense it through the first condenser 24 to the distillation column 25; then close the valve;

[0060] S12: Open the thirteenth valve 13 to transfer the remaining liquid in the distiller to the second residual liquid collector 28;

[0061] S13: Turn on the fourth constant temperature heater 17 and heat to 90℃~100℃ to further distill germanium tetrachloride after preliminary distillation. The vaporized germanium tetrachloride is liquefied and collected in the germanium tetrachloride collector 27 through the second condenser 26.

[0062] S14: Open the twenty-ninth valve 29 to discharge the remaining liquid into the second residual liquid collector 28.

[0063] S15: Take a portion of the sample from germanium tetrachloride collector 27 and use ICP-OES to test its arsenic content and germanium tetrachloride purity. The arsenic removal rate is 85% to 99%, and the germanium tetrachloride is stable at 5N or higher.

[0064] Example 3

[0065] refer to Figure 1 , Figure 2 The arsenic removal method includes the following steps:

[0066] S1: Take 10 mL of crude germanium tetrachloride and determine the arsenic content of germanium tetrachloride by potassium bromate titration method to be 2.34 g / L;

[0067] S2: Based on the parameter range, the molar ratio of As:H2O2 is set to 1:2.5. This is calculated as follows:

[0068] Let A = 0.5 L. Given X = 2.34 g / L, then Y = 0.0156 mol.

[0069] Let Y:Z be 1:2.5, then Z = 0.029 mol.

[0070] Therefore, B ≈ 0.044LC = 0.029L;

[0071] Where X is the arsenic content (g / L), Y is the molar mass of arsenic, Z is the molar mass of H2O2, A is the volume of germanium tetrachloride, B is the volume of H2O2, and C is the volume of HCl;

[0072] S3: Open the fourth, fifth, sixth, and seventh valves, and introduce 500 mL of germanium tetrachloride, 44 mL of 30% H2O2, and 29 mL of 37% HCl into the first reactor 18, then close the injection valve;

[0073] S4: Start the first constant temperature heater 14 and heat to 30℃. Then turn on the first mechanical stirrer 21 and stir and oxidize for 120 min. Stirring rate is 60 r / min. Turn off the first mechanical stirrer 21 and let the liquid in the first reactor 18 stand for a period of time for 30 min before separating the liquid.

[0074] S5: Open valves 9 and 10 to transfer the initially extracted germanium tetrachloride from the lower layer to the second reactor 19, and then close the valves;

[0075] S6: Open valves 9 and 11 to discharge the remaining waste liquid in the first reactor 18 into the first residual liquid collector 20, and then close the valves;

[0076] S7: Open valves 5, 6 and 8, add 44 mL of 30% H2O2 and 29 mL of 37% HCl to the second reactor 19, and then close the valves;

[0077] S8: Turn on the second constant temperature heater 15 and heat to 30℃. Then turn on the second mechanical stirrer 22 and stir at 120 r / min for 90 min. Further oxidize germanium tetrachloride to remove arsenic after the first arsenic removal. After the oxidative extraction is complete, let it stand for 30 min and then separate the liquid.

[0078] S9: Open valves 10 and 12 to transfer the germanium tetrachloride extracted in the second extraction below into distiller 23, and then close the valves;

[0079] S10: Open the tenth and eleventh valves to discharge the remaining waste liquid into the first residual liquid collector 20, and then close the valves;

[0080] S11: Open the twelfth valve and the third constant temperature heater 16 to heat to 95°C for preliminary distillation of germanium tetrachloride after oxidative extraction. The germanium tetrachloride is then liquefied and condensed in the first condenser 24 and sent to the distillation column 25. Then close the valve.

[0081] S12: Open the thirteenth valve to transfer the remaining liquid in the distiller to the second residual liquid collector 28;

[0082] S13: Turn on the fourth constant temperature heater 17 and heat to 95°C to further distill germanium tetrachloride after preliminary distillation. The vaporized germanium tetrachloride is liquefied and collected in the germanium tetrachloride collector 27 through the second condenser 26.

[0083] S14: Open the twenty-ninth valve to discharge the remaining liquid into the second residual liquid collector 28.

[0084] S15: A portion of the sample was taken from the germanium tetrachloride collector 27, and its arsenic content and germanium tetrachloride purity were determined using ICP-OES. The results showed that the arsenic content in germanium tetrachloride was 0.08542 g / L, the arsenic removal rate reached 96.35%, and GeCl4 ≥ 99.9999%.

[0085] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for removing arsenic from germanium tetrachloride by hydrogen peroxide oxidation, characterized in that, The arsenic removal device includes storage containers for GeCl4, H2O2, and HCl. The storage containers are connected to a first reactor and a second reactor via pipelines, and are equipped with a fourth valve, a fifth valve, a sixth valve, a seventh valve, and an eighth valve. A first constant-temperature heater is installed at the bottom of the first reactor, and a first mechanical stirrer is installed at the top. A first residual liquid collector is connected to the bottom of the reactor via a pipeline. A ninth valve and an eleventh valve are installed between the first reactor and the first residual liquid collector. The second reactor is equipped with a second constant temperature heater at the bottom, a second mechanical stirrer at the top, and a distiller connected to the bottom via a pipe, with a tenth valve and a twelfth valve on the pipe. The distiller is equipped with a third constant temperature heater at the bottom, and a second residual liquid collector connected to the bottom via a pipe, with a thirteenth valve on the pipe. The ninth and eleventh valves are connected to the tenth and twelfth valves by a connecting pipe, which is connected to the first condenser. The first condenser is connected to the distillation column by a pipe. The top of the distillation column is connected to a second condenser and a germanium tetrachloride collector in sequence via pipes. The bottom is equipped with a fourth constant temperature heater. The bottom is connected to a second residual liquid collector via pipes, and a twenty-ninth valve is installed on the pipes. Arsenic removal methods include the following steps: S1: Take crude germanium tetrachloride and determine the arsenic content in the crude germanium tetrachloride solution using potassium bromate titration. S2: Calculate the molar mass of arsenic based on the measured arsenic content and the total amount of GeCl4 added. The molar ratio of As to H2O2 is 1:1 to 20. Calculate the volume of H2O2. The volume ratio of HCl to H2O2 is 1:1.1 to 10. Calculate the amount of HCl based on the volume of H2O2. S3: Open the fourth, fifth, sixth, and seventh valves to introduce a measured amount of GeCl4, 30% H2O2 solution, and 37% HCl solution into the first reactor, and then close the valves; S4: Start the first constant temperature heater and heat to a temperature <48℃. Then turn on the first mechanical stirrer and stir and oxidize for 45 min to 120 min. Stirring rate is 60 r / min to 180 r / min. Turn off the first mechanical stirrer and let the liquid in the first reactor stand for a period of time before separating the liquid. S5: Open valves 9 and 10 to transfer the initially extracted germanium tetrachloride from the lower layer to the second reactor, then close the valves; S6: Open valves 9 and 11 to discharge the remaining waste liquid in the first reactor into the first residual liquid collector, and then close the valves; S7: Open valves 5, 6 and 8, add the amounts of H2O2 and HCl determined in step S2 to the second reactor, and then close the valves; S8: Turn on the second constant temperature heater and heat to a temperature <48℃. Then turn on the second mechanical stirrer and stir at a speed of 60 r / min to 180 r / min for 45 min to 120 min. Further oxidize germanium tetrachloride to remove arsenic after the first arsenic removal. After the oxidative extraction is complete, let it stand for a period of time and then separate the liquids. S9: Open valves 10 and 12 to transfer the germanium tetrachloride extracted in the second extraction below into the distiller, and then close the valves; S10: Open the tenth and eleventh valves to discharge the remaining waste liquid into the first residual liquid collector, and then close the valves; S11: Open the twelfth valve and the third constant temperature heater, heat to 90℃~100℃ to perform preliminary distillation of germanium tetrachloride after oxidative extraction, and liquefy and condense it in the first condenser to the distillation column; then close the valve; S12: Open the thirteenth valve to transfer the remaining liquid in the distiller to the second residual liquid collector; S13: Turn on the fourth constant temperature heater and heat to 90℃~100℃ to further distill the germanium tetrachloride after preliminary distillation. The vaporized germanium tetrachloride is liquefied and collected in the germanium tetrachloride collector through the second condenser. S14: Open the twenty-ninth valve to discharge the remaining liquid into the second residual liquid collector.

2. The method according to claim 1, characterized in that, In steps S4 and S8, the heating temperature is 20℃~40℃.

3. The method according to claim 1, characterized in that, In steps S4 and S8, the settling time is 30 min to 45 min.

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