A method for extracting germanium from a germanium-containing solution by adsorption separation with chelating resin

Abstract

The present application relates to the technical field of dispersed metal germanium extraction and separation, and discloses a method for adsorbing, separating, enriching and extracting germanium from a germanium-containing solution by using chelating resin, which is suitable for a germanium-containing solution with an initial germanium concentration of 1 mg / L-500 mg / L.The method comprises the following steps: pH adjustment, impurity removal by activated carbon pretreatment, germanium adsorption by CH-73 chelating resin, desorption by sulfuric acid solution after reverse flushing with pure water, germanium enrichment by step-by-step coprecipitation with ferric trichloride, and preparation of germanium concentrate by filtration and drying.The method cooperatively uses the selective adsorption of CH-73 chelating resin under weak acid conditions and the high-efficiency desorption by sulfuric acid, the germanium adsorption rate reaches 98.5%-99.4%, the elution rate reaches 98.25%-99.72%, the overall germanium recovery rate is higher than 95%, and the germanium concentrate grade reaches 32.1%-47.15%.The process flow is short, the resin can be recycled and regenerated, and the filtrate can be reused, and the method has the characteristics of strong adaptability, low energy consumption, and clean and environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the extraction and separation technology of scattered metal germanium, and particularly to a method for adsorbing, separating and extracting germanium from a germanium-containing solution by using a chelating resin. BACKGROUND

[0002] Germanium is a kind of rare and scattered metal, and is a very important strategic mineral, which is widely used in the fields of semiconductor, optical fiber communication, infrared optics, space power supply, etc. Germanium-containing lignite and germanium-containing lead-zinc ore are one of the main raw materials for industrial germanium extraction. In the extraction process, different concentrations of germanium-containing leaching solution are obtained. The subsequent traditional wet extraction of germanium mainly uses the chemical precipitation method of tannic acid and the like for separation and enrichment process.

[0003] The traditional germanium separation and enrichment process has many disadvantages: first, the content of main matrix and other impurity ions in the germanium-containing solution is high, which seriously interferes with the separation and recovery, resulting in low overall recovery rate of germanium and low grade of germanium concentrate; second, the process flow is too long, the process is complex, and the overall energy consumption is high; third, the content of co-precipitated impurities in the precipitate is high, which makes it difficult to improve the grade of the concentrate; fourth, a large amount of wastewater and waste residue is generated in the production process, which has a great pressure on environmental protection treatment.

[0004] The resin exchange adsorption method for extracting germanium is a new type of wet high-efficiency separation and enrichment technology, which has the advantages of strong selectivity, high enrichment multiple, simple operation and continuous operation, etc. However, the conventional ion exchange resin has poor selectivity for germanium in the germanium-containing solution and weak anti-interference ability of impurities, which is difficult to adapt to various types of germanium-containing solution systems. Therefore, it is urgent to develop a new extraction process for separating and enriching germanium by using resin adsorption, which is suitable for various types of germanium-containing solution, has high selectivity, high recovery rate, low cost and is green and environmentally friendly, and has become a hot spot in the germanium industry. SUMMARY

[0005] The purpose of the present application is to overcome the problems existing in the traditional wet extraction process of germanium from germanium-containing solution, and to provide a method for separating, enriching and extracting germanium from germanium-containing solution produced in the process of germanium production and use.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A method for adsorbing, separating and enriching extraction of germanium from germanium-containing solution by using chelating resin, comprising the following steps:

[0008] 1) pH adjustment: adjust the pH value of the germanium-containing solution to 2.0-5.0 by using sulfuric acid, filter after standing for 6 h, separate the precipitate produced, and obtain the germanium-containing solution to be adsorbed;

[0009] 2) Pretreatment of impurities removal: add activated carbon with a volume of 2% of the adsorption liquid to the solution to be adsorbed containing germanium, and stand for adsorption at room temperature for more than 12 hours to remove organic matter in the solution to be adsorbed containing germanium, and then filter to remove activated carbon and suspended solids to obtain the pre-adsorption solution;

[0010] 3) Resin adsorption of germanium: pass the pre-adsorption solution into an ion exchange column filled with CH-73 chelating resin for adsorption to obtain germanium-loaded resin, and collect the post-adsorption solution, which is recycled for production after treatment.

[0011] 4) Resin desorption of germanium: after reverse flushing of the germanium-loaded resin with pure water to near neutral (adjusting the pH value to 6.5-7), use a sulfuric acid solution with a mass concentration of 3%-8% and a dosage of 2-4 times the volume of the resin as an eluent to elute germanium from the germanium-loaded resin, and collect the eluate;

[0012] 5) Neutralization and co-precipitation enrichment of germanium: after adjusting the pH of the eluate to 8.0-9.5 by adding a 40% mass fraction sodium hydroxide solution, add ferric chloride, the addition amount of ferric chloride being 50-100 times the amount of germanium metal in the eluate, adjust the pH to 6.5-7.5 again, stir for 100-150 minutes, the reaction temperature being 40-50°C, and stand for precipitation for more than 12 hours;

[0013] 6) Germanium concentrate preparation: filter the precipitate to obtain a germanium-containing precipitate, and obtain germanium concentrate after drying, the filtrate generated is recycled for use in the pH adjustment process, and the part that cannot be used is treated and discharged after reaching the standard.

[0014] Preferably, in step 2), the adsorption amount of activated carbon is 1%-3% of the liquid volume, the adsorption is carried out at room temperature without stirring for more than 10 hours, the chemical oxygen demand COD of the pre-adsorption solution is controlled to be less than 300 ppm, the suspended solids SS is less than 10 ppm, and the hardness is less than 1 mmol / L.

[0015] Preferably, in step 4), the mass concentration of the sulfuric acid solution is 5%, and the dosage is 3 times the volume of the resin.

[0016] Preferably, in step 5), the addition amount of ferric chloride is 100 times the amount of germanium metal in the eluate, the stirring reaction time is 150 minutes, and the reaction temperature is 45°C.

[0017] pH control: adjust the pH of the solution to 2.0-5.0 with sulfuric acid, which can maximize the reduction of the competitive adsorption of coexisting impurity ions, create a favorable environment for the selective adsorption of germanium ions by the resin, and at the same time will not cause a large amount of hydrolysis and precipitation of impurity ions.

[0018] Pretreatment of the adsorption liquid: the active carbon is used for adsorption to remove the colored substances, organic impurities and hardness in the neutralization liquid, and then the suspended solids are intercepted through 0.45 mu m microporous filter membrane, so that the impurity pollution and the chelating resin column blockage are avoided, and the resin adsorption performance is ensured.

[0019] Selective adsorption of germanium by the resin: the CH-73 chelating resin has high selective adsorption capacity for germanium ions, can capture germanium from a low-concentration germanium-containing solution, realizes the preliminary separation and enrichment of germanium, and the germanium content in the adsorption liquid is very low, so that the standard-reached recycling and the repeated regeneration of the resin can be realized.

[0020] Reverse cleaning and desorption of germanium by sulfuric acid: the adsorbed germanium on the resin can be completely desorbed by using a 5% mass fraction sulfuric acid solution as an eluent, so that a high-concentration germanium-rich solution is obtained, and the secondary concentration and enrichment of germanium are realized; compared with a hydrochloric acid solution, the elution efficiency of the sulfuric acid solution is greatly improved, and the elution rate is stably above 99.5%.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] High germanium recovery rate: the hydrolysis precipitation and competitive adsorption of coexisting impurity ions are inhibited in a weak acid environment, so that the germanium selective chelation sites of the CH-73 chelating resin can be fully utilized, the germanium adsorption rate is 98.5%-99.4%, the desorption rate can reach 98.25%-99.72% by using a 3%-8% mass concentration sulfuric acid solution, which is significantly higher than 73.61% of the hydrochloric acid elution, and the overall germanium comprehensive recovery rate is higher than 95%.

[0023] High germanium concentrate grade: the CH-73 chelating resin has specific capture capacity for germanium under the condition of pH 2.0-5.0 weak acid, and the co-adsorption of impurity ions is greatly reduced; the ferric trichloride is hydrolyzed and co-precipitated with germanium under the conditions of pH 8.0-9.5 and 6.5-7.5, the obtained precipitate has few impurities, and the germanium concentrate grade can reach 32.1%-47.15% after drying, so that the germanium concentrate can directly enter the hydrochloric acid distillation process for further processing.

[0024] Stable resin operation and continuous production: the active carbon pretreatment can control the chemical oxygen demand of the adsorption liquid below 300 ppm, the suspended solids below 10 ppm, and the hardness below 1 mmol / L, so that the covering of organic matters on the chelation functional groups of the CH-73 resin and the blockage and pollution of the resin column by the suspended solids and hardness ions are effectively avoided, and the long-term stability of the resin adsorption performance is ensured; the CH-73 chelating resin can be recycled and regenerated after being eluted by sulfuric acid, and the supporting industrial exchange device can realize large-scale continuous production.

[0025] Strong process adaptability and low acid consumption: weakly acidic adsorption conditions of pH 2.0-5.0 can directly match the acidic germanium-containing solution produced by the hydrometallurgical process, without the need to adjust the solution to strong alkalinity in advance; the process can stably treat a wide range of germanium-containing solutions with an initial germanium concentration of 1 mg / L-500 mg / L; the filtrate produced by filtration is returned to the pH adjustment process for recycling, the sulfuric acid elution system has good compatibility with the overall process, and the acid consumption and wastewater discharge are significantly reduced.

[0026] Low energy consumption and green environmental protection: the main adsorption and elution processes are completed at normal temperature and pressure without the need for high-temperature and high-pressure equipment; no large amount of hazardous waste is produced during the production process, the adsorbed liquid is reused after treatment, part of the precipitate filtrate is returned to the pH adjustment process for recycling, the waste liquid is discharged less, and it is clean and environmentally friendly. DETAILED DESCRIPTION

[0027] Example 1: The raw material is an alkali leaching solution containing germanium, the germanium concentration is 37.41 mg / L, the pH of the raw solution is 13.2, the chemical oxygen demand (COD) is 210 mg / L, the solid suspended matter (SS) is 6.7 mg / L, and the hardness is 0.91 mmol / L.

[0028] 1) pH adjustment: take 1000 L of the above germanium-containing solution, neutralize it with sulfuric acid to a pH of 2.51, stand for more than 6 h, filter and separate the precipitate to obtain the germanium-containing solution to be adsorbed.

[0029] 2) Pretreatment of impurities: add activated carbon at 2% of the volume of the adsorption liquid to the germanium-containing solution to be adsorbed, stand for adsorption overnight (more than 12 h) at room temperature without stirring, filter with a 0.45 μm microporous filter to remove activated carbon and suspended matter, and obtain a clear pre-adsorption liquid. The chemical oxygen demand (COD) of the pre-adsorption liquid is detected to be <300 ppm, the suspended matter (SS) is <10 ppm, and the hardness is <1.0 mmol / L.

[0030] 3) Resin adsorption of germanium: take 20 kg of CH-73 chelating resin and pack it in an ion exchange column, rinse with pure water until the effluent is clear, pass the pre-adsorption liquid into the exchange column, and perform adsorption at normal temperature and pressure to obtain germanium-loaded resin and collect the post-adsorption liquid. The germanium adsorption rate of the resin is measured to be 99.4%, and the post-adsorption liquid is reused for production after treatment.

[0031] 4) Resin desorption of germanium: reverse flush the germanium-loaded resin with 3 times the volume of the resin with pure water, then pass 3 times the volume of the resin with a 5% mass concentration sulfuric acid solution for elution, and collect the eluate. The germanium elution rate is measured to be 98.25%, and 60.1 L of high-concentration germanium-rich eluate is obtained.

[0032] 5) Neutralization and co-precipitation enrichment of germanium: 40% sodium hydroxide solution was added to the germanium-rich eluate, the pH was adjusted to 8.8, 50 times the weight of germanium metal in the eluate was added to ferric chloride, the pH was adjusted to 7.0 again, and the reaction was stirred at 45°C for 120 min. After the reaction was completed, the precipitate was allowed to stand for 12 h or more.

[0033] 6) Filtration and drying to prepare germanium concentrate: the precipitate was separated by filtration and dried to obtain germanium concentrate. The germanium grade was 32.1%. Part of the filtrate generated by filtration was returned to the pH adjustment process for recycling, and part was treated and discharged after reaching the standard.

[0034] Example 2: The raw material was an alkali leaching solution containing germanium, the germanium concentration was 410 mg / L, the original solution pH was 13.2, the chemical oxygen demand (COD) was 120 mg / L, the solid suspended matter (SS) was 3.6 mg / L, and the hardness was 0.42 mmol / L.

[0035] 1) pH adjustment: 1000 L of the above-mentioned germanium-containing solution was neutralized to a pH of 4.75 using sulfuric acid, and allowed to stand for 6 h or more. The precipitate was separated by filtration to obtain a germanium-containing solution ready for adsorption.

[0036] 2) Pretreatment and impurity removal: 2% of the adsorption liquid volume of activated carbon was added to the germanium-containing solution ready for adsorption, and the solution was allowed to stand overnight (12 h or more) at room temperature without stirring. The activated carbon and suspended matter were removed by filtration using a 0.45 μm microporous filter to obtain a clear pre-adsorption solution. The chemical oxygen demand (COD) of the pre-adsorption solution was <300 ppm, the suspended matter (SS) was <10 ppm, and the hardness was <1.0 mmol / L.

[0037] 3) Resin adsorption of germanium: 20 kg of CH-73 chelating resin was packed into an ion exchange column, and the pre-adsorption solution was passed into the exchange column for adsorption at normal temperature and pressure to obtain germanium-loaded resin, and the post-adsorption solution was collected. The germanium adsorption rate of the resin was 98.5%, and the post-adsorption solution was treated and reused in production after reaching the standard.

[0038] 4) Resin desorption of germanium: the germanium-loaded resin was backwashed with 3 times the volume of pure water, and then eluted with 4 times the volume of 5% sulfuric acid solution to collect the eluate. The germanium elution rate was 99.72%, and 80.2 L of high-concentration germanium-rich eluate was obtained.

[0039] 5) Neutralization and co-precipitation enrichment of germanium: 40% sodium hydro xide solution was added to the germanium-rich eluate, the pH was adjusted to 8,7, 100 times the weight of germanium metal in the eluate was added to ferric chloride, the p H was adjusted to 7.3 again, and the reaction was stirred at 45°C for 150 min. After the reaction was completed, the precipitate was allowed to stand for 12 h.

[0040] 6) Filtration and drying to prepare germanium concentrate: the precipitate is separated by filtration using a filter press, and the precipitate is dried to obtain germanium concentrate. The germanium grade is 47.15%. Part of the filtrate generated by filtration is returned to the pH adjustment process for recycling, and part is treated and discharged after reaching the standard.

[0041] Comparative Example 1, hydrochloric acid elution: the same germanium-containing solution raw material and all process parameters of steps 1) to 3), 5) to 6) as in Example 1 are used, only the eluent in step 4) is replaced with a 5% mass concentration hydrochloric acid solution, and the remaining parameters remain unchanged.

[0042] The measured germanium adsorption rate of the resin is 98.06%, and the hydrochloric acid elution rate is only 73.61%, which is much lower than the sulfuric acid system, the germanium-rich liquid concentration is low, and the subsequent germanium concentrate grade is only 25.3%.

[0043] Comparative Example 2, no pretreatment impurity removal: the same germanium-containing solution raw material and all process parameters of steps 1), 3), 4), 5) to 6) as in Example 1 are used, only step 2) is omitted, and the remaining parameters remain unchanged.

[0044] The measured germanium adsorption rate of the resin is only 84.81%, and the resin is invalid after 3 uses and needs to be regenerated, and the subsequent germanium concentrate grade is only 27.69%.

[0045] Comparative Example 3, no pH adjustment direct adsorption: the same germanium-containing solution raw material and all process parameters of steps 2), 3), 4), 5) to 6) as in Example 1 are used, only step 1) is omitted, and the remaining parameters remain unchanged.

[0046] The measured germanium adsorption rate of the resin is only 6.27%, indicating that the resin belongs to an acid condition for adsorbing germanium, and in the absence of pH adjustment, the germanium-containing liquid is alkaline, and the resin hardly adsorbs germanium under alkaline conditions.

[0047] Comparative Example 4, one-step precipitation: the same germanium-containing solution raw material and all process parameters of steps (1), (2), (3), (4), (5) to (6) as in Example 1 are used, only one pH adjustment is performed in step (5) (pH is adjusted to 7.0 after adding FeCl3 directly, without first adjusting the pH to 8.0-9.5), the germanium precipitation rate is 88.7%, the germanium precipitation is incomplete, and the concentrate grade is 26.96%, proving that stepwise pH adjustment can optimize the co-precipitation effect.

[0048] Comparative Example 5, different resin: similar weakly acidic cation exchange resin D113 was used to replace CH-73, under weakly acidic (pH 2.51) conditions, the same germanium-containing solution raw material and steps 1), 2), 3) were used, CH-73 was replaced by D113, and the whole process parameters of steps 4), 5) to 6) were used. The adsorption rate was only 37.66%, which was significantly lower than CH-73. The adsorption efficiency of this type of resin for germanium was significantly lower than that of CH-73.

[0049] As can be seen from the examples and comparative examples, in the weakly acidic adsorption system of CH-73 chelating resin, the germanium elution rate can reach 98.25%-99.72% using a 3%-8% sulfuric acid solution as the eluent, which is significantly better than the 73.61% of the hydrochloric acid elution system; combined with the weakly acidic adsorption conditions of pH 2.0-5.0, activated carbon pretreatment and step-by-step co-precipitation of ferric chloride, high-efficiency enrichment and purification of germanium in the germanium-containing solution can be stably realized, the germanium concentrate grade reaches 32.1%-47.15%, the overall germanium comprehensive recovery rate is higher than 95%, and the technical indicators are significantly better than those of the traditional process.

Claims

1. A method for the adsorptive separation and enrichment of germanium extracted from a solution containing germanium with a chelating resin, suitable for the extraction of germanium from a solution containing germanium with an initial concentration of germanium of 1 mg / L - 500 mg / L, characterized in that The method comprises the following steps: 1) pH adjustment: the pH value of the germanium-containing solution is adjusted to 2.0-5.0 by using concentrated sulfuric acid with a mass concentration of 98%, and the solution is filtered after standing for 6 h, and the generated precipitate is separated to obtain a germanium-containing solution to be adsorbed; 2) pretreatment and impurity removal: 2% of activated carbon by volume of the adsorption liquid is added to the germanium-containing solution to be adsorbed, and the solution is adsorbed at room temperature for more than 12 h to remove organic matter and suspended solids in the solution, and then the activated carbon and suspended solids are removed by filtration to obtain a pre-adsorption solution; 3) resin adsorption of germanium: the pre-adsorption solution is introduced into an ion exchange column filled with CH-73 chelating resin for adsorption to obtain germanium-loaded resin, and an after-adsorption solution is collected, which is recycled for production after treatment; 4) resin desorption of germanium: the germanium-loaded resin is back-flushed with pure water, and then the pH value is adjusted to 6.5-7, and a sulfuric acid solution with a mass concentration of 3%-8% and a dosage of 2-4 times the volume of the resin is used as an eluent to elute germanium from the germanium-loaded resin, and an eluate is collected; 5) neutralization and co-precipitation enrichment of germanium: a 40% sodium hydroxide solution is added to the eluate to adjust the pH value to 8.0-9.5, and then ferric chloride is added in an amount of 50-100 times the amount of germanium metal in the eluate, and the pH value is adjusted to 6.5-7.5 again, and the stirring reaction time is 100 min-150 min, the reaction temperature is 40°C-50°C, and the solution is statically precipitated for more than 12 h; 6) germanium concentrate preparation: the precipitate is filtered to obtain a germanium-containing precipitate, which is dried to obtain a germanium concentrate, and the filtrate is returned to the pH adjustment process for recycling, and the unrecycled part is discharged after treatment.

2. The method of claim 1, wherein, In step 2), the activated carbon adsorption amount is 2% of the liquid volume, the adsorption is performed at room temperature without stirring for more than 10 h, the chemical oxygen demand COD of the pre-adsorption solution is controlled to be less than 300 ppm, the suspended solids SS is less than 10 ppm, and the hardness is less than 1 mmol / L.

3. The method of claim 1, wherein, The mass concentration of the sulfuric acid solution is 5%, and the dosage is 3 times the volume of the resin.

4. The method of claim 1, wherein, In step 5), the amount of ferric chloride added is 100 times the amount of germanium metal in the eluate, the stirring reaction time is 150 min, the reaction temperature is 45°C, and the static precipitation time is 12 h.