Method for extracting germanium from low germanium-containing solution in two stages using N235 kerosene extractant

Abstract

The invention discloses a method for extracting germanium from a low-germanium-containing solution in two stages using an N235 kerosene extractant, comprising the steps of: preparing a unified N235 kerosene extractant, adding the extractants to two extraction tanks respectively, wherein the first stage is extracted at level 1 to 2 to extract germanium in the original solution, and the second stage is extracted at level 3 to 4 to extract germanium in the raffinate of the first stage of germanium extraction; step 2: performing in vitro pumping full reflux extraction on the two extraction organic phases respectively, and using this as a control condition for the germanium loading amount in the first extraction organic phase; step 3: if the total extraction rate of the second stage of step 2 is lower than 80%, the first stage of the germanium-loaded organic phase is sent to alkali stripping; step 4: after the first stage of the germanium-loaded organic phase of step 3 is stripped of germanium by alkali stripping, acidification and regeneration are performed with sulfuric acid, and then the germanium is extracted in the second stage. The invention can significantly increase the amount of germanium loaded in the organic phase, is conducive to reducing the consumption of NaOH and the output of sodium salt by alkali stripping, and ensures the total extraction rate of germanium.

Description

Technical Field

[0001] The invention relates to the field of comprehensive recovery of rare and scattered metals, and in particular to a method for extracting germanium from a low-germanium-containing solution in two stages using an N235 kerosene extractant. Background Art

[0002] Germanium is an extremely rare and dispersed rare metal, which is widely used in high-tech fields. Germanium is generally associated with lead-zinc ore, copper ore or coal. Its extraction mainly adopts wet acid leaching, and tannin precipitation or organic solvent extraction is used to extract it from the acidic liquid. After more than two enrichments, the content of germanium in the acidic liquid can generally reach 50-80 mg / L. If the raw material contains high germanium, it can reach more than 100 mg / L, and only about 10 mg / L when it is low. Due to the gradual depletion of germanium-rich raw materials, the germanium in most leaching solutions is currently below 40 mg / L. Due to the rarity and high price of tannin, it takes more than 35 times tannin to precipitate the low-germanium solution to less than 1 mg / L of germanium in the liquid. Tannin precipitation of germanium is very expensive and has poor economic benefits. At present, both at home and abroad, efforts are being made to research and develop extraction methods for germanium extraction.

[0003] When using N235 kerosene extractant to extract germanium from germanium-containing acidic liquid, the N235 organic phase must first extract acid, that is, it must first be acidified to form an anion-cation association state [R3NH+(HS04)-], and then react with tartaric acid germanium acid (H2(Ge(C406H4) to form [(R3NH+)2(GeC406H4)2-]+H2S04, and obtain [(R3NH+2(GeC406H4)2] association complex and be extracted, where R3N represents N235 molecules. When the germanium content is low, the N235 organic phase contains a large amount of acid. Using such a low The alkaline stripping of the organic phase loaded with germanium will inevitably consume a large amount of alkali for stripping acid, resulting in a low germanium content and a high sodium sulfate content in the stripping solution, which is not conducive to the subsequent hydrolysis and precipitation of germanium concentrate. N235 is a weakly alkaline anionic extractant. After extracting germanium, it can only be stripped with alkali. This is determined by the chemical properties and extraction mechanism of N235. When germanium is extracted with cationic extractants such as hydroxamic acid, hydroxamic acid or 8-hydroxyquinoline, germanium is extracted in the form of a chelate and needs to be extracted at a higher acidity. Stripping is carried out using a high acid or F-containing acidic solution. The acidic stripping solution needs to use a large amount of alkali to neutralize the hydrolysis and precipitation of the germanium concentrate. A large amount of Na 2 S0 4Output is inevitable. Even if the oxime acid extractant is modified, NaOH solution can be used for stripping. For the germanium extraction of low-germanium-containing liquid, stripping will consume alkali and produce a large amount of sodium salt like N235 extractant. Therefore, whether it is N235 or hydroxamic acid or modified hydroxamic acid extractant to extract germanium, it is necessary to solve the problem of low-germanium extraction, low germanium content in the organic phase, which is not conducive to stripping and producing a large amount of sodium salt. In order to increase the germanium content in the organic phase, some people have studied low-concentration organic phase extraction and small-phase (organic phase / aqueous phase) extraction of germanium. Due to the low effective ingredients in the extractant or too little organic phase, there are problems of low effective contact probability and low extraction rate during mixed stirring extraction. Some people have also studied the extraction of the organic phase without dividing it into one or two stages in the extraction section, and full reflux extraction of the organic phase. Since the number of stages of germanium extraction is large, the overall organic phase consumption is large, the extraction is not easy to saturate or the load of the extractant in the organic phase is slow. When the amount of germanium loaded is increased, the residual liquid must contain high germanium, and the total extraction rate decreases. If the total extraction rate is limited to 80%, due to the large volume of the organic phase, the germanium content therein must still be very low, which is not conducive to stripping. Others have studied the in vivo (in the extraction tank) reflux extraction equipment and process of the organic phase, that is, two organic phase overflow ports at height difference positions are set in the sedimentation tank of each stage of the extraction. The low overflow port is connected to the darkroom of the mixing and stirring chamber of this stage through a pipeline, and the reflux volume is controlled by a valve, or a small-diameter pipeline is used, one end of which is immersed in the organic phase layer of the sedimentation chamber, and the other end is connected to the mixing and stirring chamber or the lower part of the normal overflow port of the organic phase, forming a partial reflux of the organic phase, such as the Chinese patent CN20151629B. Regardless of the reflux method adopted, the organic phase refluxed at this stage in the body is small, which has no practical significance for achieving a high load rate for the extracted organic phase. If a large amount or all of the recovery is carried out, the countercurrent extraction of the organic phase cannot be carried out normally, and it becomes a dead tank extraction without organic phase flow, and continuous production cannot be achieved. Therefore, for the extraction of germanium from low-germanium solution, it is necessary to better increase the amount of germanium loaded in the organic phase. The two-stage extraction process of the present invention is currently the best solution. Summary of the invention

[0004] The object of the present invention is to provide a method for extracting germanium from a low-germanium-containing solution in two stages using N235 kerosene extractant.

[0005] The technical solution for achieving the purpose of the present invention is: a method for extracting germanium from a low-germanium-containing solution in two stages using N235 kerosene extractant, comprising the following implementation steps:

[0006] Step 1. Extracting germanium from a low germanium-containing solution using N235 kerosene extractant is divided into two stages, the first stage is 1-2 levels, the second stage is 3-4 levels, the organic phases of the two stages are uniformly prepared, the N235 concentration is the same, and the extraction phase ratio (organic phase / aqueous phase) is the same;

[0007] Step 2. The first stage of extraction of germanium in step 1 is carried out from the original solution with low germanium content, and the organic phase is continuously refluxed to extract the germanium in the original solution to obtain an organic phase with high germanium loading;

[0008] Step 3. The second stage of extraction of germanium in step 1 is carried out from the extraction residue of germanium in the first stage, the organic phase is continuously refluxed to extract germanium from the extraction residue of the first stage, the second stage extraction residue is sent to other processes for treatment, and the organic phase of the second stage extraction is not subjected to alkali stripping;

[0009] Step 4. The extraction rate of germanium in the second stage is used as the limit of the reflux extraction of the organic phase of the first stage of germanium extraction, that is, when the efficiency of the second stage of germanium extraction drops below the limit, the reflux of the organic phase of the first stage of extraction is stopped and sent to the stripping section for alkali stripping of germanium, the stripping degerminated organic phase is regenerated with acid and then enters the second stage of extraction for use, and the organic phase of the second stage is promoted to the first stage of extraction with a corresponding volume of organic phase as the 1-2 level organic phase to extract germanium from the original solution;

[0010] Step 5. The reflux extraction method of the extracted organic phase in the first and second stages is to pump the extracted organic phase in vitro to reflux it to the mixing and stirring chamber of the extraction tank for extraction. The in vitro reflux is performed by setting a low-level tank for the organic phase or directly connecting the overflow port of the extraction sedimentation tank to the pump.

[0011] Preferably, the low germanium-containing solution in step 1 is an acidic zinc sulfate solution or other germanium-containing acidic solution containing germanium ≤ 40 mg / L.

[0012] Preferably, the N235 volume percentage concentration of the organic phase extracted by N235 kerosene is 20-30% (20-30% N235, 70-80% kerosene), and the ratio of the first and second stage extractions (organic phase / aqueous phase) is 1 / 5-1 / 3.

[0013] Preferably, the continuous total reflux extraction in step 2 and step 3 is that the first-stage extraction organic phase continuously refluxes to extract germanium in the original germanium-containing solution, and the organic phase is not in a hurry to perform alkali stripping but is pumped back to continue extracting germanium in the original germanium-containing solution, thereby achieving a high germanium load in the organic phase, and the residual liquid continuously enters the second-stage extraction to extract germanium, and the organic phase of the second-stage extraction also continuously refluxes to extract germanium in the residual liquid of the first stage, and the organic phase of the second-stage extraction does not perform alkali stripping.

[0014] Preferably, the germanium extraction rate in the second stage of step 4 is limited to less than 80% of the germanium extraction rate, and the organic phase extracted in the first stage is no longer refluxed to extract germanium, but sent to the stripping stage for alkali stripping of germanium.

[0015] By adopting the above technical scheme, the present invention has the following beneficial effects: (1) The present invention uses N235 kerosene extractant to extract germanium from a low-germanium-containing solution in two stages, wherein the first stage is to extract germanium in the original solution by full reflux of the organic phase, and the main task is to increase the amount of germanium loaded in the organic phase, which is beneficial to reduce the consumption of NaOH and the output of sodium salt by alkali stripping. The second stage is to extract germanium in the residual solution of the first stage of germanium extraction by full reflux of the organic phase, and the main task is to ensure that the total extraction rate of germanium (the total extraction rate refers to the total extraction rate of germanium from the first stage of the original solution to the second stage of the extraction) reaches a certain level, and serves as a limit for the amount of germanium loaded in the organic phase of the first stage of extraction.

[0016] (2) The first stage of extraction of the organic phase can obtain a higher germanium loading, reduce the number of alkali stripping times and reduce the alkali consumption of alkali stripping, while reducing the output of sodium salt, which is beneficial to the environmental protection of the three wastes. DETAILED DESCRIPTION

[0017] In order to overcome the problems of high alkali consumption and large sodium salt output in the low-germanium solution extraction process, the present invention proposes a two-stage extraction process, that is, the first stage of extraction is 1 to 2 levels, and the main task is to increase the germanium content in the extracted organic phase as much as possible, that is, the organic phase is repeatedly fully refluxed to extract the germanium in the original solution to achieve a higher content of germanium in the extracted organic phase. The second stage of extraction is 3 to 4 levels, and the main task is to ensure that the total extraction rate of germanium reaches a higher requirement, that is, the total extraction rate of germanium in the first stage of germanium extraction residual liquid is maintained at a higher level by repeatedly refluxing the organic phase to extract the germanium, and this higher level of germanium extraction rate is used as the limit of the number of reflux extractions of the germanium load in the first stage of extraction of the organic phase. The full reflux of the organic phase in the two stages of extraction is achieved by in vitro pumping, and the specific implementation is as follows.

[0018] Step 1. Prepare a uniform N235 kerosene extractant and add it to two extraction tanks respectively. The first extraction is 1-2 levels, extracting germanium from the original solution, and the second extraction is 3-4 levels, extracting germanium from the residual solution of the first extraction. The low-germanium acidic liquid is a zinc sulfate leaching solution or other acidic liquid containing germanium ≤40mg / L. The organic phases of the two extractions are uniformly prepared, with the same N235 concentration and the same extraction phase ratio (organic phase / aqueous phase). The low-germanium solution in step 1 is an acidic zinc sulfate solution or other germanium-containing acidic liquid containing germanium ≤40mg / L. The volume percentage concentration of N235 in the organic phase of the N235 kerosene extraction is 20-30% (20-30% N235, 70-80% kerosene), and the first and second extraction phase ratios (organic / water) = 1 / 5-1 / 3.

[0019] Step 2. The two extracted organic phases are respectively subjected to in vitro pumping total reflux extraction. The main task of the first reflux extraction is to increase the amount of germanium loaded in the organic phase. The amount of loading is determined by the set extraction rate of germanium in the second extraction. The main task of the second extraction is to maintain the total extraction rate of germanium ≥ 80%, and use this as the control condition for the amount of germanium loaded in the organic phase of the first extraction. The total extraction rate is calculated by the germanium content of the original solution and the germanium content of the residual solution of the second extraction. The first extraction of germanium in step 1 is carried out from a low-germanium original solution, and the organic phase is continuously fully refluxed to extract the germanium in the original solution to obtain an organic phase with a high germanium load.

[0020] Step 3. The second stage of extraction of germanium in step 1 is carried out from the extraction residue of germanium in the first stage, and the organic phase is continuously refluxed to extract germanium in the extraction residue of the first stage. The second stage extraction residue is sent to other processes for treatment, and the second stage extraction organic phase is not subjected to alkali stripping. If the total extraction rate of the second stage of step 2 is lower than 80%, the first stage loaded germanium organic phase is sent to alkali stripping. The second stage extracted organic phase is promoted to the first stage for extraction according to the volume of the organic phase removed in the first stage. Step 2, the continuous reflux extraction of step 3 is that the first stage extraction organic phase continuously refluxes to extract germanium in the original solution containing germanium, and the organic phase is not eager to perform alkali stripping and is pumped back to continue to extract germanium in the original solution containing germanium, so as to achieve high germanium load in the organic phase, and the raffinate continuously enters the second stage to extract germanium. The second stage extraction organic phase also continuously refluxes to extract germanium in the first stage extraction residue, and the second stage extraction organic phase does not perform alkali stripping.

[0021] Step 4. After the first stage of the germanium-loaded organic phase of step 3 is stripped of germanium by alkali stripping, it is acidified and regenerated with sulfuric acid, and then enters the second stage for germanium extraction. The extraction rate of germanium in the second stage is used as the limit of the reflux extraction of the organic phase of the first stage of germanium extraction, that is, when the efficiency of the second stage of germanium extraction drops below the limit, the first stage of extraction organic phase stops refluxing and is sent to the stripping section for alkali stripping of germanium. The stripping stripped germanium organic phase is regenerated with acid and enters the second stage for extraction. The organic phase of the second stage is promoted to the first stage of extraction with a corresponding volume of organic phase as the 1-2 level organic phase to extract germanium from the original solution. The limit of the second stage of germanium extraction rate in step 4 is set according to the production situation, and is generally set to a germanium extraction rate of about 80%. If it is lower than 80%, the first stage of extraction organic phase will no longer reflux to extract germanium, but will be sent to the stripping section for alkali stripping of germanium.

[0022] Step 5. The reflux extraction method of the first and second extraction organic phases is to pump the extracted organic phases back to the mixing and stirring chamber of the extraction tank by external pumping (referring to the outside of the extraction tank) for extraction. The external reflux can be performed by setting a low-level tank for the organic phase or directly connecting the overflow port of the extraction sedimentation tank to the pump.

[0023] After implementing the above steps, the beneficial effects obtained are: the first stage extraction of the organic phase can obtain a higher germanium loading, reduce the number of alkali stripping times and reduce the alkali consumption of alkali stripping, while reducing the output of sodium salt, which is beneficial to the environmental protection of the three wastes.

[0024] Working principle of the present invention:

[0025] The extraction of germanium from germanium-containing acidic liquid by N235 is anion exchange extraction, that is, N235 first forms anion-cation association complex [(R3NH)+(HS04)-] with sulfuric acid, and then exchanges anions with germanium tartrate Ge(C406H4)2-, and associates to form [R3NH]2+Ge(C406H4)2- ion pair and is extracted. And sulfuric acid is released. Since the volume percentage concentration of N235 in kerosene is 20-30%. When the germanium content is low, only a small amount of germanium tartrate anions are exchanged with hydrogen sulfate anions, and the organic phase still contains a large amount of sulfuric acid. At this time, alkaline stripping is carried out, and the reaction R3NH(HS04)+2Na0H→R3N+Na2S04+2H20 will occur, which will inevitably consume a large amount of Na0H for useless work and produce a large amount of waste Na2S04. If low-concentration N235 is used for extraction, in the mixed stirring extraction, the contact probability of N235 and the germanium complex anion is small, which is not conducive to the extraction of germanium. Especially for low germanium-containing solutions, the contact probability of N235 and the germanium complex is smaller, and the extraction rate is lower. Increasing the extraction ratio (organic phase / aqueous phase) can improve the extraction effect, but the ratio cannot be infinitely increased, because the large ratio extraction will produce the phenomenon of water-in-oil, making the phase separation difficult and slow, and will increase the mechanical loss of the organic phase. If only the stripping alkali solution is used to return for use many times, the content of germanium in the stripping solution can be improved, but the alkali consumption and the output of sodium salt are not reduced. Because when returning for use many times, the alkali is consumed, and the alkali must be supplemented to ensure the concentration of the alkali to ensure the alkali stripping rate of germanium. Therefore, the two-stage extraction process of the present invention is the best solution for solving the extraction of germanium with low germanium solution at present.

[0026] Example

[0027] Example 1. The zinc sulfate leaching solution of a certain enterprise contains Ge: 38mg / L, H2S04: 50g / L, tartaric acid is added as a germanium complexing agent, and the H2GeO3 in the solution is converted into tartaric germanium acid: H2GeC4O6H4→Ge(C406H4)2-+2H+, and two-stage extraction is carried out with acidified N235 kerosene extractant. The first stage of extraction is 2 levels, and the second stage of extraction is 4 levels. The organic phase of the two stages of extraction was fully refluxed for 3 times. The residual liquid of each extraction in the first stage contains Ge (mg / L) 3.23, 5.7, 9.12; the extraction rates are (%) 91.5, 85.3, 76 respectively. The residual liquid of each extraction in the second stage contains germanium (mg / L), 2.6, 3.04, 5.32; the total extraction rates of each time are (%), 93.1, 92, 86.1 respectively. After the organic phase of the first stage extraction was refluxed for 3 times, it was subjected to alkali stripping. The NaOH concentration was 30%, the stripping stage was 2, and the first stage stripping solution contained Ge: 83.6 mg / L, and the total stripping rate of the two-stage stripping was: 98.2%.

[0028] Example 2. The main chemical components of the germanium-containing acid leaching solution are: Ge35.5mg / L, Fe3+: 16.8mg / L, SiO2: 177mg / L. The acidity pH is 2, and tartaric acid is added at a tartaric acid / germanium ratio of 8. The organic phase extracted with N235 in Example 1 was subjected to 5 full reflux extractions, wherein the organic phase of the second extraction stage promoted two levels of organic phases to the first stage as the organic phase of the first extraction stage, and the stripped germanium organic phase of Example 1 was acidified and regenerated with 100g / L sulfuric acid and then added to the second extraction stage to participate in the extraction. The results are as follows. The residual liquid of each extraction stage contained germanium (mg / L) of 6.37, 7.4, 8.9, 12.8, 16.8; the extraction rate (%) of each extraction stage was 86, 83, 80.5, 71.8, 63. The residual liquids of the second extraction stage contained Ge (mg / L) of 3.6, 4.05, 7.2, 8.9, and 10.8; the total extraction rates (%) of each time were 92, 90.1, 84.2, 80.4, and 76.2. After 5 total reflux extractions, the organic phase loaded with germanium from the first extraction stage was subjected to two-stage alkaline stripping after supplementing with 5g NaOH with the alkaline stripping solution of Example 1. The first-stage stripping solution contained 194mg / L germanium, and the first-stage stripping rate was 98.5%.

[0029] Example 3. The second stage of the organic phase of Example 2 was promoted to the first stage of extraction by two levels. The first stage of the organic phase of Example 2 was subjected to alkali stripping and degermanium extraction and then acidified before entering the second stage of extraction. The germanium-containing acid leaching solution of Example 2 was used for three full reflux extractions, and the results were as follows: the extraction rate (%) of each stage in the first stage was 70.7, 61.2, 58.6; the total extraction rate (%) calculated for each stage in the second stage was 85.6, 82, 82.3. The first stage of the germanium-loaded organic phase reverse extraction continued to use the stripping solution of Example 2 to add 5g NaOH for stripping, and the first stage stripping solution contained 390mg / L of germanium. Three rounds of full reflux extraction and stripping were continued, each round of full reflux extraction was performed 3 times, and one stage of the organic phase was stripped once, and a total of 3 rounds of full reflux extraction and stripping were performed (9 total reflux extractions and 3 strippings). The average primary extraction rates (%) of each round were 57, 61.8, and 57.2, respectively, and the Ge content (mg / L) of the primary stripping solution was 490.4, 586.6, and 790.4, respectively.

[0030] The germanium-containing acid leaching solution of Example 2 was extracted by conventional 6-stage countercurrent extraction (no segmentation, no reflux of organic phase), and the first-level organic phase of each extraction was subjected to alkali stripping, and the stripping solution was repeatedly used. After every 3 strippings, the stripping solution was supplemented with 3g of alkali and returned for continued use, and a total of 42 extractions and strippings were performed. The total extraction rate was above 85% each time, and alkali was supplemented 10 times in 42 strippings, with a total of 30g of alkali supplemented, and the average stripping rate was 98%. The stripping solution after 42 strippings contained 687mg / L of germanium. The present invention actually extracted 12 times with full reflux, stripped 4 times in total, supplemented alkali 2 times, supplemented alkali 10g in total, saved 20g of alkali, and the germanium content in the stripping solution was about 100mg / L higher, and the effect of saving alkali consumption was obvious.

[0031] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for extracting germanium from a low germanium-containing solution in two stages using N235 kerosene extractant, characterized in that: The implementation steps include: Step 1. Extracting germanium from a low-germanium-containing solution using N235 kerosene extractant is divided into two stages, the first stage of extraction is 1-2 levels, the second stage of extraction is 3-4 levels, the organic phases of the two stages of extraction are uniformly prepared, the N235 concentration is the same, and the extraction phase ratio, i.e., the organic phase / aqueous phase is the same; the low-germanium-containing solution is an acidic zinc sulfate solution containing germanium ≤ 40 mg / L or other acidic solution containing germanium; Step 2. The first stage of extraction of germanium in step 1 is carried out from the original solution with low germanium content, and the organic phase is continuously refluxed to extract the germanium in the original solution to obtain an organic phase with high germanium loading; Step 3. The second stage of extraction of germanium in step 1 is carried out from the extraction residue of germanium in the first stage, the organic phase is continuously refluxed to extract germanium from the extraction residue of the first stage, the second stage extraction residue is sent to other processes for treatment, and the organic phase of the second stage extraction is not subjected to alkali stripping; Step 4. The extraction rate of germanium in the second stage is used as the limit of the reflux extraction of the organic phase of the first stage of germanium extraction, that is, when the efficiency of the second stage of germanium extraction drops below the limit, the reflux of the organic phase of the first stage of extraction is stopped and sent to the stripping section for alkali stripping of germanium, the stripping degerminated organic phase is regenerated with acid and then enters the second stage of extraction for use, and the organic phase of the second stage is promoted to the first stage of extraction with a corresponding volume of organic phase as the 1-2 level organic phase to extract germanium from the original solution; Step 5. The reflux extraction method of the extracted organic phase in the first and second stages is to pump the extracted organic phase in vitro to reflux it to the mixing and stirring chamber of the extraction tank for extraction. The in vitro reflux is performed by setting a low-level tank for the organic phase or directly connecting the overflow port of the extraction sedimentation tank to the pump.

2. The method for extracting germanium from a low germanium-containing solution in two stages using N235 kerosene extractant as claimed in claim 1, characterized in that: The volume percentage concentration of N235 in the organic phase extracted with N235 kerosene is 20-30%, the volume percentage concentration of kerosene is 70-80%, and the ratio of the first and second stage extractions, i.e., the organic phase / aqueous phase, is 1 / 5-1 / 3.

3. The method for extracting germanium from a low germanium-containing solution in two stages using N235 kerosene extractant as claimed in claim 1, characterized in that: In step 2 and step 3, the continuous total reflux extraction is that the first stage of extraction of the organic phase is continuously refluxed to extract the germanium in the original germanium-containing solution, the organic phase is not in a hurry to perform alkali stripping and is pumped back to continue to extract the germanium in the original germanium-containing solution, so as to achieve a high germanium load in the organic phase, and the residual liquid continuously enters the second stage of extraction to extract germanium, the second stage of extraction of the organic phase is also continuously refluxed to extract the germanium in the first stage of extraction of the organic phase, and the second stage of extraction of the organic phase is not subjected to alkali stripping.

4. The method for extracting germanium from a low germanium-containing solution in two stages using N235 kerosene extractant as claimed in claim 1, characterized in that: The germanium extraction rate of the second stage of step 4 is limited to less than 80% of the germanium extraction rate, and the organic phase of the first stage extraction is no longer refluxed to extract germanium, but sent to the stripping stage for alkali stripping of germanium.