A method for detoxifying and regenerating germanium and indium poisoned by N235 and P204.

Abstract

This invention discloses a method for detoxifying and regenerating poisoned N235 and poisoned P204 phases in the extraction of germanium and indium, comprising the following steps: Step 1, removing the N235 organic phase poisoned by germanium extraction and the P204 organic phase poisoned by indium extraction from an acidic zinc sulfate solution containing germanium and indium, and sending them to a detoxification and regeneration extraction tank system; Step 2, detoxifying and regenerating the poisoned N235 organic phase from Step 1; the detoxification and regeneration steps are: first-stage washing with dilute sulfuric acid, second-stage detoxification with sodium sulfite solution, and first-stage acidification regeneration with sulfuric acid; Step 3, detoxifying and regenerating the poisoned P204 organic phase from Step 1; Step 4, replenishing the N235 regenerated organic phase from Step 2 and the P204 regenerated organic phase from Step 3 with 5-10% kerosene before reuse. The detoxification and regeneration technology of this application is simple, easy to operate, has low environmental protection pressure, and low detoxification and regeneration costs.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to a method for detoxifying and regenerating germanium and indium by extracting poisoned N235 and poisoned P204. Background Technology

[0002] When recovering germanium and indium from the intermediate leaching residue after neutral leaching of zinc oxide raw materials containing germanium, indium, silicon, iron, and other impurities, the impurities precipitated in the intermediate leaching residue, such as SiO2, Fe3+, arsenic, antimony, bismuth, nickel, and cobalt, are also leached out along with germanium and indium. After desiliconization and iron removal treatment, the acid leaching solution still contains 100–300 mg / L of SiO2 and 30–50 mg / L of Fe3+. Under these silicon and iron contents, the extraction of germanium with N235 and the extraction of indium with P204 can proceed smoothly without the formation of SiO2 emulsion. Therefore, further purification of impurities is not required (further deep purification is difficult and economically unfeasible, and a small amount of Fe2+ in the solution will be oxidized to Fe3+ by air during extraction and stirring, so Fe3+ cannot actually be completely removed). As extraction continues, both the N235 and P204 organic phases are affected to varying degrees by the aforementioned impurities. SiO2 primarily causes emulsification of N235 and P204, making phase separation between the organic and aqueous phases difficult and hindering smooth production, but it does not cause organic phase poisoning. Fe3+, on the other hand, causes poisoning of N235 and P204, but does not affect phase separation between the organic and aqueous phases, allowing extraction to proceed smoothly. However, severe poisoning will cause a rapid decrease in the extraction rate. Fe3+ poisoning is a slow process; when it accumulates to a certain level, it can reduce the germanium-indium extraction rate to below 60%. In extraction production, this is considered severe organic phase poisoning and must be removed from the extraction system for detoxification and regeneration.

[0003] Currently, there are three main methods for detoxification and regeneration: The first method involves using over 40% NaOH at 80-90℃ to stir and wash to regenerate N235 and P2O4; the second method uses HF or fluoride salts (commonly NH4F) to wash and regenerate P2O4; and the third method uses microwave radiation to treat SiO2 emulsions for desilication and regeneration of N235 and P2O4. High-temperature concentrated alkali washing results in significant kerosene volatilization loss in the organic phase and requires more than 10 hours of settling for phase separation. Fe3+ eluted in the alkali solution hydrolyzes into Fe(OH)3 colloid, making concentrated alkali solution difficult to filter, and alkali boiling regeneration cannot be performed in an extraction tank, thus making the recovery of the organic phase cumbersome. Using HF or fluoride salts mainly detoxifies Fe3+, causing it to precipitate as hexafluoroferric salt, but the regenerated solution contains fluoride ions, which are harmful to operators and corrosive to treatment equipment, placing significant pressure on environmental governance. The microwave treatment described in patent CN108486370B only targets SiO2 emulsions and cannot detoxify Fe3+. Therefore, the current main treatment method is high-temperature concentrated alkali treatment. There is a need to develop a regeneration method that overcomes the shortcomings of detoxification and regeneration technologies for poisoning N235 and P2O4 caused by Fe3+. Summary of the Invention

[0004] The purpose of this invention is to provide a method for detoxifying and regenerating germanium-indium poisoned by N235 and P204.

[0005] The technical solution to achieve the objective of this invention is: a method for detoxifying and regenerating germanium-indium poisoned N235 and P204, comprising the following steps:

[0006] Step 1 involves removing the N235 organic phase (poisoned by germanium) and the P204 organic phase (poisoned by indium) from the zinc sulfate acidic solution containing germanium and indium, and sending them to the detoxification and regeneration extraction tank system.

[0007] Step 2: Detoxify and regenerate the poisoned N235 organic phase from Step 1. The detoxification and regeneration steps are as follows: first-stage washing with dilute sulfuric acid, second-stage detoxification with sodium sulfite solution, and first-stage acidification and regeneration with sulfuric acid.

[0008] Step 3: Detoxify and regenerate the poisoned P204 organic phase from Step 1;

[0009] Step 4: The N235 regenerated organic phase from Step 2 and the P204 regenerated organic phase from Step 3 are replenished with 5-10% kerosene and then returned for reuse.

[0010] Preferably, in step 2, the detoxification and regeneration temperature of the poisoned N235 organic phase is 20–40°C.

[0011] As a preferred embodiment, in step 3, the detoxification and regeneration steps of the poisoned P204 organic phase are as follows: primary water washing, two-stage sodium sulfite detoxification, primary washing and regeneration with a mixture of oxalic acid and hydrochloric acid, and primary water washing.

[0012] Preferably, in step 3, the detoxification and regeneration temperature of the poisoned P204 organic phase is 20–40°C.

[0013] As a preferred method, poisoning N235 reduces the efficiency of germanium extraction in zinc sulfate solution containing germanium and indium to below 60%, and poisoning P204 reduces the efficiency of indium extraction to below 70%.

[0014] Preferably, in step 2, the concentration of the dilute sulfuric acid washing solution is 50-100 g / L, the sodium sulfite detoxification and regeneration solution is 10-20% sodium sulfite solution, and the acidification and regeneration solution is 100-200 g / L sulfuric acid solution.

[0015] Preferably, the sodium sulfite detoxification and regeneration solution in step 3 is a 10-20% sodium sulfite solution, and the oxalic acid and hydrochloric acid mixture is a 5% oxalic acid and 2-3N hydrochloric acid mixture.

[0016] The present invention has the following beneficial effects by adopting the above technical solution: (1) The present invention proposes to use an extraction tank to wash the poisoned N235 organic phase with dilute sulfuric acid in the first stage, detoxify it with sodium sulfite in the second stage, and regenerate it with acidification in the first stage. The poisoned P204 organic phase is washed with water in the first stage, detoxified with sodium sulfite in the second stage, washed with a mixture of oxalic acid and hydrochloric acid in the first stage, and washed with water in the first stage. The beneficial effects obtained are that the detoxification and regeneration technology is simple, easy to operate, has low environmental protection pressure, and low detoxification and regeneration cost.

[0017] (2) There are few residues in the organic phase and it is less harmful to the production of electrolytic zinc.

[0018] (3) The beneficial effects obtained through the above steps are that the extraction efficiency of germanium from the poisoned N235 organic phase is restored from about 60% to about 90%, and the extraction efficiency of indium from the poisoned P204 organic phase is restored from 60-70% to more than 90%. The operation is simple, and the detoxification and regeneration can be repeated in multiple stages to improve the detoxification capacity. The environmental protection pressure of the detoxification and regeneration solution is small, and the detoxification and regeneration cost is low. Detailed Implementation

[0019] In this application, poisoning N235 reduces the efficiency of germanium extraction to below 60% in zinc sulfate solution containing germanium and indium, and poisoning P204 reduces the efficiency of indium extraction to below 70%.

[0020] The method for detoxifying and regenerating germanium-indium poisoned by N235 and P204 poisoning in this application includes the following steps:

[0021] Step 1 involves extracting the germanium-poisoned N235 organic phase and the indium-poisoned P204 organic phase from the zinc sulfate acidic solution containing germanium and indium, and then transferring them to a dedicated detoxification and regeneration extraction tank system.

[0022] Step 2: Detoxify and regenerate the poisoned N235 organic phase from Step 1 at 20–40°C. The detoxification and regeneration process consists of a first-stage washing with dilute sulfuric acid (50–100 g / L), primarily washing away ZnSO4, tartaric acid, and its germanium salt in the organic phase while maintaining a certain sulfuric acid content in the N235; a second-stage detoxification with sodium sulfite (10–20% Na2SO3); and a third-stage acidification regeneration (100–200 g / L sulfuric acid).

[0023] Step 3: The poisoned P2O4 organic phase from Step 1 is detoxified and regenerated at 20–40°C. The detoxification and regeneration process consists of a first-stage washing with water to primarily elute ZnSO4, followed by two-stage detoxification with sodium sulfite (NaSO3 concentration of 10–20%), a first-stage washing with a mixture of oxalic acid and hydrochloric acid (5% oxalic acid and 2–3N hydrochloric acid), and a final washing with water to primarily elute oxalic acid and hydrochloric acid.

[0024] Step 4: The N235 regenerated organic phase from Step 2 and the P204 regenerated organic phase from Step 3 are replenished with 5-10% kerosene and then returned for reuse.

[0025] The working principle of this invention is as follows:

[0026] In acidic solutions containing germanium and indium, SiO2 can cause emulsification of the N235 and P204 organic phases during extraction, but this does not affect the extraction efficiency of germanium and indium. Slight emulsification can be removed by back-extraction of N235 with alkali or by saponification of P204 to form Na2SiO4, which dissolves in the alkali solution. Severe emulsification requires removal and elimination with concentrated alkali at high temperature. Fe3+ in the germanium-indium solution is preferentially extracted by N235 over germanium tartrate and by P204 over In3+, forming a relatively stable extract. During alkali back-extraction of N235 or hydrochloric acid back-extraction of P204, this extract is not easily back-extracted into the solution and remains in the organic phase, gradually reducing the extraction capacity of the organic phase. When the ferric extract accumulates to a certain amount in the organic phase, it severely affects the extraction rate of germanium and indium. Water washing alone, not acid washing, cannot decompose this extract. Using a NaOH solution with a concentration of over 40% for detoxification and regeneration at high temperatures forcibly hydrolyzes Fe3+ in the iron extractant into Fe(OH)3 or generates more stable ferrates, thereby destroying the iron extractant and achieving detoxification and regeneration. However, the high concentration of alkaline solution and high-temperature operation require iron or ceramic-lined containers, making the phase separation and recovery of the detoxification solution and organic phase difficult, resulting in high kerosene volatilization and detoxification costs. Using HF or fluoride salts to detoxify Fe3+ generates hexafluoroferric salts to decompose the iron extractant. However, both HF and fluoride salts pose environmental problems, and the introduction of fluoride ions into the electrolytic zinc production system is also undesirable. This invention utilizes the principle and practice that N235 or unsaponifiable P204 essentially does not extract ferrous iron in acidic solutions. Sulfite is used to wash the N235 and P204 organic phases containing a certain amount of acid. The sulfite reacts with the acid in the organic phase, decomposing to produce SO2, which reduces Fe3+ to Fe2+ and enters the solution. Alternatively, Fe3+ directly undergoes a redox reaction with sodium sulfite, reducing Fe3+ to Fe2+ and oxidizing sulfite to sulfate, thereby destroying the iron extract. Sodium sulfite has the highest solubility among sulfite components, resulting in a clear detoxifying solution, the best detoxification effect, and the lowest price. While using SO2 gas directly for detoxification is theoretically possible, there are gas-liquid contact issues with the poisoned organic phase, and SO2 cannot dissolve in kerosene-containing organic phases, leading to poor actual detoxification. Furthermore, the SO2 gas will carry away a significant amount of kerosene through volatilization. Fe2+ ​​entering the detoxification solution, under a reducing atmosphere, is not easily oxidized to Fe3+ and will not be further extracted by the organic phase. The acidification treatment of the detoxified N235 serves two purposes: firstly, to elute and decompose residual sodium sulfite in the organic phase; and secondly, it is required by the mechanism of N235 extraction of germanium. The regeneration of P204 with a mixture of oxalic acid and hydrochloric acid follows the same principle; oxalic acid can further elute iron, and hydrochloric acid can further back-extract and detoxify other impurities in P204. This invention uses an extraction tank for the detoxification and regeneration operation, which not only ensures good phase separation between the organic and aqueous phases and facilitates recovery, but also allows for easy addition of detoxification stages to improve the detoxification level.Why can't the sodium sulfite detoxification and regeneration operation be directly used in routine extraction production systems? The reason is that if the sodium sulfite detoxification and regeneration operation is connected after N235 alkaline back-extraction, the organic phase lacks acid, preventing the decomposition of sodium sulfite to obtain SO2. If connected after the acidification section, the high acid content in the organic phase causes excess acid to enter the sodium sulfite solution, leading to sodium sulfite decomposition and unstable sodium sulfite content, making it difficult to stably perform the detoxification and regeneration function. If used before back-extraction, it will cause some decomposition and elution of the germanium extract, hindering germanium back-extraction recovery. For the P204 extraction of indium, indium back-extraction is carried out at high hydrochloric acid concentrations above 6N. Performing sodium sulfite detoxification and regeneration after back-extraction will further destabilize the operation; operating it before back-extraction will disperse the indium back-extraction recovery. Therefore, only severely poisoned organic phases can be removed and treated separately. This invention is simple to operate, has low detoxification and regeneration costs, minimal environmental hazards from waste liquid, few residues in the organic phase, and minimal harm to electrolytic zinc production.

[0027] The following examples illustrate this point:

[0028] Example 1: A company's zinc sulfate solution containing germanium and indium, after desilication and removal of trivalent iron, had the following chemical composition: Ge 40-60 mg / L, In 2000-2600 mg / L, Fe3+ 30-40 mg / L, SO2 250-3000 mg / L, Zn 100-130 g / L, H+ 70-80 g / L. Germanium was first extracted using a 30% N235 kerosene organic phase, followed by indium extraction using a 30% P204 kerosene organic phase. After 6 cycles of extraction (extraction, back-extraction, acidification regeneration, and return to extraction constitute one cycle), the extraction rate of germanium was 87.8%, and the extraction rate of indium was 99.5%. After 18 cycles, the germanium extraction rate decreased to 82.2%, and the indium extraction rate decreased to 84.4%; after 32 cycles, the germanium extraction rate decreased to 63.3%, and the indium extraction rate decreased to 71.8%. The poisoned organic phase was removed for detoxification and regeneration treatment. The detoxification and regeneration process for N235 involved a primary wash with 100 g / L sulfuric acid, followed by a two-stage detoxification and regeneration process with a 10% sodium sulfite solution, and a primary acidification with 150 g / L sulfuric acid before being returned to the germanium extraction process. After six extraction cycles, the average germanium extraction rate was 87%. The detoxification and regeneration process for poisoned P204 involved a primary wash with water, a two-stage detoxification and regeneration process with a 10% sodium sulfite solution, a primary wash with a mixture of 5% oxalic acid and 2N hydrochloric acid, a final primary wash with water, and then being returned to the indium extraction process. After six extraction cycles, the average indium extraction rate was 88%. The recovery rate of N235 detoxification and regeneration was 38.1%, and that of P204 was 24%.

[0029] Example 2: The germanium-indium cyclic extraction from Example 1 was performed 62 times. The extraction rate of germanium using N235 decreased to 58%, and the extraction rate of indium using P204 decreased to 60.2%. The poisoned organic phase was removed for detoxification and regeneration. The sodium sulfite concentration in the two-stage detoxification and regeneration solutions was adjusted to 15%, while other conditions remained unchanged. The detoxified and regenerated organic phase was returned to the extraction process. After 18 cycles of extraction, the average extraction rate of germanium was 84.1%, and the average extraction rate of indium was 90.5%. The recovery rate of N235 detoxification and regeneration was 45%, and the recovery rate of P204 detoxification and regeneration was 50.3%.

[0030] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are 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 within the protection scope of the present invention.

Claims

1. A method for detoxifying and regenerating germanium-indium poisoned N235 and P204, characterized in that: Includes the following steps: Step 1 involves removing the N235 organic phase (poisoned by germanium) and the P204 organic phase (poisoned by indium) from the zinc sulfate acidic solution containing germanium and indium, and sending them to the detoxification and regeneration extraction tank system. Step 2: Detoxify and regenerate the poisoned N235 organic phase from Step 1. The detoxification and regeneration steps are as follows: first-stage washing with dilute sulfuric acid, second-stage detoxification with sodium sulfite solution, and first-stage acidification and regeneration with sulfuric acid. Step 3: Detoxify and regenerate the poisoned P204 organic phase from Step 1; The detoxification and regeneration steps for the organic phase of poisoned P204 are as follows: primary water washing, two-stage sodium sulfite detoxification, primary washing and regeneration with a mixture of oxalic acid and hydrochloric acid, and primary water washing; Step 4: The N235 regenerated organic phase from Step 2 and the P204 regenerated organic phase from Step 3 are replenished with 5-10% kerosene and then returned for reuse.

2. The method for detoxifying and regenerating germanium-indium poisoned N235 and P204 poisoning during extraction according to claim 1, characterized in that: In step 2, the detoxification and regeneration temperature of the poisoned N235 organic phase is 20~40℃.

3. The method for detoxifying and regenerating germanium-indium extracted from poisoned N235 and poisoned P204 according to claim 1, characterized in that: In step 3, the detoxification and regeneration temperature of the poisoned P204 organic phase is 20~40℃.

4. The method for detoxifying and regenerating germanium-indium poisoned N235 and P204 poisoning during extraction according to claim 1, characterized in that: Poisoning N235 reduces the efficiency of germanium extraction to below 60% in zinc sulfate solution containing germanium and indium, while poisoning P204 reduces the efficiency of indium extraction to below 70%.

5. The method for detoxifying and regenerating germanium-indium poisoned N235 and P204 poisoning during extraction according to claim 2, characterized in that: In step 2, the concentration of the dilute sulfuric acid washing solution is 50~100g / L sulfuric acid solution, the sodium sulfite detoxification and regeneration solution is 10~20% sodium sulfite solution, and the acidification and regeneration solution is 100~200g / L sulfuric acid solution.

6. The method for detoxifying and regenerating germanium-indium extracted from poisoned N235 and poisoned P204 according to claim 1, characterized in that: The sodium sulfite detoxification and regeneration solution in step 3 is a 10-20% sodium sulfite solution, and the oxalic acid and hydrochloric acid mixture is a 5% oxalic acid and 2-3N hydrochloric acid mixture.