Method for recovering germanium and chlorine from chlorine-containing germanium slag for deep processing of germanium

Abstract

The invention relates to a method for recovering germanium and chlorine from germanium deep processing chlorine-containing germanium slag, and belongs to the technical field of chlorine-containing germanium slag treatment.According to the method, the germanium in the chlorine-containing germanium slag is efficiently recovered by adopting a two-section countercurrent alkaline leaching-ion exchange separation and enrichment combined process, the germanium is recovered as a high-quality and high-purity GeCl4 product, the germanium recovery process is greatly simplified, and the production cost is reduced. And the problems of difficulty in recovery and low recovery rate when the germanium in the chlorine-containing germanium slag is converted into another germanium solid enrichment from the chlorine-containing germanium slag in the prior art are solved. Chlorine is produced in the form of hydrochloric acid and used in the process, and the problems of corrosion and pollution of chlorine in the chlorine-containing germanium slag treatment process are solved.

Description

Technical Field

[0001] This invention belongs to the field of chlorine-containing germanium slag treatment technology, specifically, it relates to a method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium. Background Technology

[0002] Currently, core processes in industrial germanium processing, such as chlorination distillation, redistillation, rectification, and hydrolysis, as well as the recovery of germanium from germanium-containing wastewater generated during these processes, are all carried out in hydrochloric acid systems. These processes all produce highly acidic chlorinated germanium slag. Currently, pyrometallurgical processes are the mainstream technology for recovering germanium from this chlorinated germanium slag. However, pyrometallurgical processes generate large amounts of hydrogen chloride gas, causing severe equipment corrosion and environmental pollution. Germanium recovery rates are low, and large quantities of difficult-to-treat chlorinated wastewater are generated, resulting in severe pollution and a lengthy process flow. Furthermore, current processes merely transform germanium from one solid form into another germanium solid concentrate, making subsequent germanium recovery difficult, costly, and resulting in a low overall germanium recovery rate. Summary of the Invention

[0003] To overcome the problems existing in the background technology, the present invention provides a method for recovering germanium and chlorine from germanium slag containing chlorine in deep processing of germanium. This method can achieve short-range and efficient recovery of both germanium and chlorine from germanium slag containing chlorine, wherein germanium is produced in the form of high-purity GeCl4 product. This method solves the problems of long processing flow and difficult germanium recovery in existing germanium slag containing chlorine.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: The method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium includes the following steps: (1) After the pretreated chlorine-containing germanium slag is mixed with alkaline solution, the first stage of alkaline leaching is carried out. After the leaching slurry is separated into liquid and solid, the first stage alkaline leaching solution and the first stage alkaline leaching residue with a residual alkali concentration of 1-10 g / L are obtained. (2) After adjusting the alkaline leaching residue of section I, the alkaline leaching of section II is carried out. After liquid-solid separation of the leaching slurry, section II alkaline leaching solution and section II alkaline leaching residue are obtained. (3) The germanium is recovered by ion exchange from the alkaline leaching solution of step (1) I.

[0005] Furthermore, the first stage of alkaline leaching is carried out using the second stage alkaline leaching solution; the amount of sodium hydroxide added in the second stage alkaline leaching is controlled so that the germanium residue in the second stage alkaline leaching residue is less than 0.05%.

[0006] Furthermore, the initial alkali concentration of stage I alkali leaching is 30-80 g / L, the reaction temperature is 60-80℃, the liquid-solid ratio is 5:1-8:1, and the time is 30-120 min; the initial alkali concentration of stage II alkali leaching is 120-180 g / L, the reaction temperature is 60-80℃, the liquid-solid ratio is 6:1-10:1, and the time is 30-120 min.

[0007] Furthermore, step (2) also includes washing the alkaline leaching residue of stage II, using rinsing or stirring to transfer the germanium entrained in the alkaline leaching residue of stage II into the washing solution, to obtain low germanium leaching final residue and washing solution.

[0008] Furthermore, the pretreatment mentioned in step (1) refers to washing away chlorine from the chlorine-containing germanium slag with water; the chlorine content of the chlorine-containing germanium slag after pretreatment is <1%; a high-chlorine washing solution is obtained after pretreatment; the high-chlorine washing solution is subjected to negative pressure distillation to obtain dilute hydrochloric acid and negative pressure distillation residue with pH 2-3.

[0009] Furthermore, hydrochloric acid solution is used as a desorbent to desorb the loaded ion exchange resin in step (3) to obtain a germanium-containing desorbent solution.

[0010] Furthermore, hydrochloric acid was added to the germanium-containing desorption solution for chlorination distillation to obtain germanium tetrachloride product and chlorinated distillate.

[0011] Further, desorption yields a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin; hydrochloric acid is added to the high-germanium solution with a germanium concentration ≥5000 mg / L for chlorination and distillation; the low-germanium solution is concentrated and then mixed with the high-germanium solution for chlorination and distillation.

[0012] Furthermore, the residual liquid from the negative pressure distillation of the high-chlorine washing solution is returned to step (3) and mixed with the alkaline leaching solution of stage I, and then germanium is recovered by ion exchange. The pH of the mixture of the alkaline leaching solution of stage I and the residual liquid from the negative pressure distillation is 7-9. The dilute hydrochloric acid obtained by the negative pressure distillation of the high-chlorine washing solution is used as a desorbent.

[0013] Furthermore, the chlorine-containing germanium slag is subjected to 2-3 stages of countercurrent water washing with stirring at room temperature for 30-90 minutes. The washing liquid from the 3rd stage is returned to the 2nd stage, and the washing liquid from the 2nd stage is returned to the 1st stage. The washing liquid from the 1st stage is the high-chlorine washing liquid.

[0014] The beneficial effects of this invention are: (1) The present invention can efficiently recover germanium and chlorine from chlorine-containing germanium slag. Germanium is produced in the form of high-purity GeCl4 product, and chlorine is produced in the form of hydrochloric acid and used in the process of the present invention. This avoids the generation of a large amount of difficult-to-treat chlorine-containing wastewater, greatly reduces the cost of chlorine-containing wastewater treatment, and the overall chlorine recovery rate of the whole process is over 93%.

[0015] (2) The present invention adopts a two-stage countercurrent alkaline leaching-ion exchange separation and enrichment process to achieve efficient recovery of germanium. The overall recovery rate of germanium in the whole process is over 95%. Compared with the current process, which converts germanium from chlorine-containing germanium slag into another type of germanium-enriched slag and requires further recovery of germanium-enriched slag, the present invention directly produces high-quality and high-purity GeCl4 products, greatly shortens and simplifies the germanium recovery process, and effectively improves the germanium yield.

[0016] (3) This invention removes chlorine from the chlorine-containing germanium slag through pretreatment, resulting in a high-chlorine washing solution that can be further recovered by negative pressure distillation. The dilute hydrochloric acid produced after negative pressure distillation can be used as a desorbent. The germanium-containing residue from negative pressure distillation can be mixed with the alkaline leaching solution of stage I, thereby adjusting the solution pH to meet the pH requirements of the ion exchange method for efficient and selective adsorption of germanium, and achieving comprehensive and efficient recovery of germanium from the residue of negative pressure distillation. No chlorine-containing wastewater is produced throughout the process, effectively solving the problem of existing processes generating a large amount of difficult-to-treat chlorine-containing wastewater. Moreover, this invention removes chloride ions before performing two-step alkaline leaching to extract germanium, greatly reducing the consumption of alkali and the adverse effect of chloride ions entering the alkaline leaching solution, which makes it difficult to obtain a high germanium adsorption rate in the subsequent ion exchange method for germanium extraction. Attached Figure Description

[0017] Figure 1 This is a simplified process flow diagram of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0019] The method for recovering germanium and chlorine from chlorine-containing germanium slag includes the following steps: Step 1, Section I: Alkali Immersion (1) Water washing dechlorination pretreatment: The chlorine-containing germanium slag is washed by 2-3 countercurrent washing at room temperature for 30-90 minutes. The third stage washing liquid is returned to the second stage, and the second stage washing liquid is returned to the first stage. The residual chlorine content in the dechlorinated germanium slag is <1%, and the chlorine content in the first stage washing liquid is above 80g / L. The first stage washing liquid is the high chlorine washing liquid.

[0020] (2) Negative pressure distillation: The high-chlorine washing solution is subjected to negative pressure distillation at a temperature of 60-80℃, a pressure of 0.01-0.09MPa, and a time of 120-240min to obtain dilute hydrochloric acid with a mass fraction of 15-20% and negative pressure distillation residue with pH 2-3. The dilute hydrochloric acid enters the desorption enrichment step, and the negative pressure distillation residue enters the adsorption separation step.

[0021] Chlorine-containing germanium slag contains a high amount of chlorine. Direct two-stage alkaline leaching would consume a large amount of sodium hydroxide alkali, increasing reagent costs. Furthermore, the leaching process would produce high-chlorine wastewater. Currently, salt distillation is commonly used for chlorine removal, which is energy-intensive and costly. By using water washing for pre-dechlorination, over 95% of the chlorine in the chlorine-containing germanium slag enters the washing solution. The high-chlorine washing solution is then distilled under negative pressure to produce dilute hydrochloric acid. This dilute hydrochloric acid is used in the process of this invention, achieving efficient chlorine removal and recycling. The entire process generates no chlorine-containing wastewater. The chlorine recovery rate in the water washing dechlorination-negative pressure distillation stage is greater than 93% (93% of the chlorine in the chlorine-containing germanium slag is converted into dilute hydrochloric acid).

[0022] (3) After the dechlorinated germanium slag that has undergone water washing and dechlorination pretreatment is mixed with the second-stage alkaline leaching solution, the first-stage alkaline leaching is carried out. The initial alkali concentration is 30-80 g / L, the reaction temperature is 60-80℃, the liquid-solid ratio is 5:1-8:1, and the time is 30-120 min. After the reaction is completed, the leaching slurry is separated into liquid and solid to obtain the first-stage alkaline leaching solution and the first-stage alkaline leaching slag with a residual alkali concentration of 1-10 g / L.

[0023] Step 2, Section II Alkali Immersion: The alkaline leaching residue from stage I was mixed with the adsorption solution and washing solution at a liquid-solid ratio of 6:1 to 10:1 and then subjected to stage II alkaline leaching. Sodium hydroxide was added to make the initial alkali concentration of the reaction slurry 120 to 180 g / L. The reaction temperature was controlled at 60 to 80℃ and the leaching time at 30 to 120 min. After the reaction was completed, the leaching slurry was separated into liquid and solid to obtain stage II alkaline leaching solution and stage II alkaline leaching residue. The residual germanium content of stage II alkaline leaching residue was less than 0.05%.

[0024] Furthermore, the alkaline leaching residue of stage II is washed by rinsing or stirring. During rinsing, process water at 60-80°C is sprayed onto the surface of the alkaline leaching residue of stage II, and then the washing liquid and leaching residue are obtained by liquid-solid separation. During stirring, process water and alkaline leaching residue of stage II are mixed at a liquid-solid ratio of 2-4:1 and then stirred and washed at 60-80°C for 30-60 minutes. After the reaction is completed, the washing liquid and leaching residue are obtained by liquid-solid separation.

[0025] This invention employs a two-stage countercurrent alkaline leaching process: Stage I alkaline leaching is performed under conditions of low initial alkaline concentration to produce a Stage I alkaline leaching solution with low residual alkaline concentration, providing conditions for achieving efficient separation of germanium using ion exchange; Stage II alkaline leaching is performed under conditions of high initial alkaline concentration to achieve efficient deep leaching of residual germanium.

[0026] The germanium leaching rate reached over 98% in the two-stage countercurrent alkaline leaching process.

[0027] Step 3: Adsorption and separation The alkaline leaching solution from stage I is mixed with the residual liquid from negative pressure distillation to obtain a mixed solution with a pH of 7-9. The mixed solution is then passed sequentially through 2-3 ion exchange columns connected in series at a flow rate of 1-4 BV. The ion exchange columns are filled with quaternary ammonium strong base resin. The switching of ion exchange columns and the opening of the adsorption liquid are achieved by controlling the residual germanium concentration in the adsorption liquid. The residual germanium concentration in the adsorption liquid after open-circuit adsorption is controlled to be <5 mg / L. After the ion exchange resin reaches saturation, the germanium-loaded resin enters the desorption enrichment process. The alkaline leaching solution from stage I is mixed with the residual liquid from negative pressure distillation to obtain a mixed solution with a pH of 7–9. When this solution is desorbed through 2–3 ion exchange columns packed with quaternary ammonium strong base resin, the functional groups of the quaternary ammonium strong base resin exhibit high selectivity and high saturation adsorption capacity for the germanium-containing mixed solution within this pH range. The residual germanium concentration in the open-circuit adsorption solution is <5 mg / L. The direct recovery rate of germanium during the adsorption separation process reaches over 99%. Step 4: Desorption and enrichment Using 15-20% hydrochloric acid (by mass) generated during negative pressure distillation as a desorbent, saturated germanium-loaded resin is desorbed to obtain a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin. The low-germanium solution is continuously evaporated and concentrated under heating conditions of 70-85℃ to obtain a high-germanium concentrate with a germanium concentration >10 g / L. Concentrated hydrochloric acid is added to the mixed solution of the high-germanium solution and the high-germanium concentrate until the hydrochloric acid concentration reaches 35%-38%. Then, chlorination distillation is directly performed at 85-95℃ for 1-4 hours to obtain a GeCl4 product with a purity of 5N-6N and chlorination distillation residue. The residual germanium concentration in the distillation residue is <100 mg / L. The distillation residue is then returned to the negative pressure distillation process.

[0028] This invention employs a stepped desorption process to produce a high-germanium solution with a germanium concentration ≥5000 mg / L and a low-germanium solution with a germanium concentration <5000 mg / L. The low-germanium solution is then concentrated to obtain a high-germanium concentrate with a germanium concentration >10 g / L. The high-germanium solution and the high-germanium concentrate are then mixed and directly subjected to chlorination distillation to obtain the GeCl4 product. The direct recovery rate of germanium during the desorption enrichment process reaches over 98%.

[0029] The germanium recovery rate of this invention is greater than 95% and the chlorine recovery rate is greater than 93% throughout the entire process.

[0030] The chlorine-containing germanium slag processed by this invention contains 5-20% chlorine and 1000-6000 g / t of germanium.

[0031] To illustrate the present invention more clearly, the following embodiments will be described in detail.

[0032] Example 1 The chlorine-containing germanium slag in this embodiment contains 11% chlorine and 6000g / t of germanium.

[0033] Step 1, Section I: Alkali Immersion (1) Water washing dechlorination pretreatment: The chlorine-containing germanium slag was washed at room temperature by a two-stage countercurrent washing method for 60 min, in which the second-stage washing liquid was returned to the first stage, and the residual chlorine content in the dechlorinated germanium slag was 0.8%. The first-stage washing liquid was a high-chlorine washing liquid with a chlorine content of 115 g / L.

[0034] (2) Negative pressure distillation: The high-chlorine washing solution was subjected to negative pressure distillation at a temperature of 60℃, a pressure of 0.01MPa, and a time of 240min, yielding 15% dilute hydrochloric acid and a negative pressure distillation residue with a pH of 2. The dilute hydrochloric acid was then subjected to a desorption enrichment step, while the negative pressure distillation residue was subjected to an adsorption separation step. The chlorine recovery rate in the water washing dechlorination-negative pressure distillation process was 93.9% (93.3% of the chlorine in the chlorine-germanium slag was converted into dilute hydrochloric acid product).

[0035] (3) After the chlorine-containing germanium slag that has been pretreated by water washing and dechlorination is mixed with the second-stage alkaline leaching solution, it is used as the first-stage alkaline leaching solution for the first-stage alkaline leaching. The initial alkali concentration is 50 g / L, the leaching temperature is 80℃, the liquid-solid ratio is 8:1, and the time is 30 min. After the leaching is completed, the leaching slurry is separated into liquid and solid to obtain the first-stage alkaline leaching solution with a residual alkali concentration of 1 g / L and the first-stage alkaline leaching slag.

[0036] Step 2, Section II Alkali Immersion: The alkaline leaching residue from stage I was mixed with the adsorption solution and washing solution at a liquid-solid ratio of 6:1 and then subjected to alkaline leaching in stage II. Sodium hydroxide was added to make the initial alkali concentration of the reaction slurry 150 g / L. The reaction temperature was controlled at 80℃ and the leaching time was 30 min. After the leaching was completed, the liquid and solid were separated to obtain alkaline leaching solution and alkaline leaching residue from stage II. The residual germanium content of the alkaline leaching residue from stage II was 0.025%.

[0037] The alkaline leaching residue of stage II was washed by rinsing. During the rinsing process, process water at 80°C was sprayed onto the surface of the alkaline leaching residue of stage II, and then the washing solution and leaching residue were obtained by liquid-solid separation.

[0038] The germanium leaching rate was 98.6% in the two-stage countercurrent alkaline leaching process.

[0039] Step 3: Adsorption and separation The alkaline leaching solution from stage I was mixed with the residual liquid from negative pressure distillation to obtain a mixed solution with a pH of 7. This mixed solution was then passed sequentially through three ion exchange columns connected in series at a flow rate of 4 BV. The ion exchange columns were filled with quaternary ammonium strong-base resin. The switching of the ion exchange columns and the opening of the adsorption path were controlled by adjusting the residual germanium concentration in the post-adsorption solution. The residual germanium concentration in the post-adsorption solution was controlled at 3 mg / L. After the ion exchange resin reached saturation, the germanium-loaded resin entered the desorption enrichment process. The direct recovery rate of germanium during the adsorption separation process was 99.3%.

[0040] Step 4: Desorption and enrichment Using 15% hydrochloric acid (by mass) generated during the negative pressure distillation process as a desorbent, saturated germanium-loaded resin was desorbed to obtain a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin. The low-germanium solution was continuously evaporated and concentrated at 80℃ to a high-germanium concentrate with a germanium concentration of 13 g / L. The high-germanium solution and the high-germanium concentrate were mixed, and concentrated hydrochloric acid was added until the hydrochloric acid concentration reached 35%. Then, direct chlorination distillation was performed at 90℃ for 2 hours to obtain a GeCl4 product with a purity of 5N and chlorination distillation residue. The residual germanium concentration in the distillation residue was 70 mg / L. The distillation residue was returned to the negative pressure distillation process. The direct recovery rate of germanium during the desorption and enrichment process was 98.5%.

[0041] In this embodiment, the germanium recovery rate is 96.4% and the chlorine recovery rate is 93.2% throughout the entire process.

[0042] Comparative Example 1 This comparative example uses the same raw materials as Example 1.

[0043] Step 1, Section I: Alkali Immersion (1) Water washing dechlorination pretreatment: The chlorinated germanium slag was stirred and washed for 60 min at room temperature using a two-stage countercurrent washing method, in which the second-stage washing liquid was returned to the first stage to obtain dechlorinated germanium slag and high-chlorine washing liquid.

[0044] (3) After the chlorine-containing germanium slag that has been pretreated by water washing and dechlorination is mixed with the second-stage alkaline leaching solution, it is used as the first-stage alkaline leaching solution for the first-stage alkaline leaching. The initial alkali concentration is 50 g / L, the leaching temperature is 80℃, the liquid-solid ratio is 8:1, and the time is 30 min. After the leaching is completed, the leaching slurry is separated into liquid and solid to obtain the first-stage alkaline leaching solution with a residual alkali concentration of 1 g / L and the first-stage alkaline leaching slag.

[0045] Step 2, Section II Alkali Immersion: The alkaline leaching residue from stage I was mixed with the adsorption solution and washing solution at a liquid-solid ratio of 6:1 and then subjected to alkaline leaching in stage II. Sodium hydroxide was added to make the initial alkali concentration of the reaction slurry 150 g / L. The reaction temperature was controlled at 80℃ and the leaching time was 30 min. After the leaching was completed, the liquid and solid were separated to obtain alkaline leaching solution and alkaline leaching residue from stage II. The residual germanium content of the alkaline leaching residue from stage II was 0.025%.

[0046] The alkaline leaching residue from stage II was washed using a rinsing method. During the rinsing process, process water at 80°C was sprayed onto the surface of the residue, followed by liquid-solid separation to obtain the washing solution and the final leaching residue. The germanium leaching rate of the two-stage countercurrent alkaline leaching was 98.6%.

[0047] Step 3: Adsorption and separation The alkaline leaching solution from stage I was adjusted to pH 7 with hydrochloric acid. The solution was then passed sequentially through three ion exchange columns connected in series at a flow rate of 4 BV. Each column was filled with a quaternary ammonium strong-base resin. The switching of the ion exchange columns and the opening of the adsorption path were controlled by adjusting the residual germanium concentration in the post-adsorption solution. The residual germanium concentration in the post-adsorption solution was maintained at 3 mg / L. After the ion exchange resin reached saturation, the germanium-loaded resin entered the desorption enrichment process. The direct recovery rate of germanium during the adsorption separation process was 99.3%.

[0048] Step 4: Desorption and enrichment Saturated germanium-loaded resin was desorbed using 15% hydrochloric acid as the desorbent, yielding a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin. The low-germanium solution was continuously evaporated and concentrated at 80°C to a high-germanium concentrate with a germanium concentration of 13 g / L. The high-germanium solution and the high-germanium concentrate were mixed, and concentrated hydrochloric acid was added until the hydrochloric acid concentration reached 35%. Then, chlorination distillation was directly performed at 90°C for 2 hours, yielding 5N GeCl4 product and chlorination distillation residue. The residual germanium concentration in the distillation residue was 70 mg / L. The distillation residue was then returned to a negative pressure distillation process. The direct recovery rate of germanium during the desorption and enrichment process was 98.5%.

[0049] The comparative example showed a germanium recovery rate of 67.5% throughout the entire process.

[0050] Example 2 The chlorine-containing germanium slag in this embodiment contains 5% chlorine and 4000g / t of germanium.

[0051] Step 1, Section I: Alkali Immersion (1) Water washing dechlorination pretreatment: The chlorine-containing germanium slag was washed with a three-stage countercurrent washing method at room temperature for 30 minutes. The third stage washing liquid was returned to the second stage, and the second stage washing liquid was returned to the first stage. The residual chlorine content in the dechlorinated germanium slag was <1%. The first stage washing liquid was a high-chlorine washing liquid with a chlorine content of 82 g / L.

[0052] (2) Negative pressure distillation: The high-chlorine washing solution is subjected to negative pressure distillation at a temperature of 70℃, a pressure of 0.05MPa, and a time of 180min to obtain dilute hydrochloric acid with a mass fraction of 20% and negative pressure distillation residue with pH 3. The dilute hydrochloric acid enters the desorption enrichment step, and the negative pressure distillation residue enters the adsorption separation step.

[0053] The chlorine recovery rate in the water washing dechlorination-negative pressure distillation process is 93.2% (93.2% of the chlorine in the chlorine-containing germanium slag is converted into dilute hydrochloric acid product).

[0054] (3) After the chlorine-containing germanium slag that has been pretreated by water washing and dechlorination is mixed with the alkaline leaching solution of stage II, the alkaline leaching of stage I is carried out. The initial alkali concentration is 30 g / L, the leaching temperature is 70℃, the liquid-solid ratio is 6:1, and the time is 90 min. After the leaching is completed, the liquid and solid are separated to obtain the alkaline leaching solution of stage I with a residual alkali concentration of 6 g / L and the alkaline leaching residue of stage I.

[0055] Step 2, Section II Alkali Immersion: The alkaline leaching residue from stage I was mixed with the adsorption solution and washing solution at a liquid-solid ratio of 10:1 and then subjected to alkaline leaching in stage II. Sodium hydroxide was added to make the initial alkali concentration of the reaction slurry 120 g / L. The reaction temperature was controlled at 60℃ and the leaching time was controlled at 120 min. After the reaction was completed, the leaching slurry was separated into liquid and solid to obtain alkaline leaching solution and alkaline leaching residue from stage II. The residual germanium content of the alkaline leaching residue from stage II was 0.04%.

[0056] The alkaline leaching residue of stage II was washed by stirring and washing. During the stirring and washing process, the process water and the alkaline leaching residue of stage II were mixed into a slurry at a liquid-solid ratio of 4:1 and then stirred and washed at 60°C for 30 minutes. After the reaction was completed, the washing liquid and the final leaching residue were obtained by liquid-solid separation.

[0057] The germanium leaching rate was 98.1% in the two-stage countercurrent alkaline leaching process.

[0058] Step 3: Adsorption and separation The alkaline leaching solution from stage I was mixed with the residual liquid from negative pressure distillation to obtain a mixed solution with a pH of 8. This mixed solution was then passed sequentially through two ion exchange columns connected in series at a flow rate of 1 BV. The ion exchange columns were filled with quaternary ammonium strong-base resin. The switching of the ion exchange columns and the opening of the adsorption path were controlled by adjusting the residual germanium concentration in the post-adsorption solution. The residual germanium concentration in the post-adsorption solution was controlled at 1 mg / L. After the ion exchange resin reached saturation, the germanium-loaded resin entered the desorption enrichment process. The direct recovery rate of germanium during the adsorption separation process was 99.5%.

[0059] Step 4: Desorption and enrichment Using 20% ​​hydrochloric acid (by mass) generated during negative pressure distillation as a desorbent, saturated germanium-loaded resin was desorbed, yielding a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin. The low-germanium solution was continuously evaporated and concentrated at 85℃ to obtain a high-germanium concentrate with a germanium concentration of 15 g / L. The high-germanium solution and the high-germanium concentrate were mixed, and concentrated hydrochloric acid was added until the hydrochloric acid concentration reached 37%. Chlorination distillation was then performed at 95℃ for 1 hour, yielding 6N GeCl4 product and chlorination distillation residue. The residual germanium concentration in the distillation residue was 90 mg / L. The distillation residue was returned to the negative pressure distillation process. The direct recovery rate of germanium during the desorption and enrichment process was 98.6%.

[0060] In this embodiment, the germanium recovery rate is 96.2% and the chlorine recovery rate is 93.1% throughout the entire process.

[0061] Example 3 In this embodiment, the chlorine-containing germanium slag contains 20% chlorine and 1000g / t of germanium.

[0062] Step 1, Section I: Alkali Immersion (1) Water washing dechlorination pretreatment: The chlorine-containing germanium slag was washed at room temperature by a three-stage countercurrent washing method for 90 min. The third stage washing liquid was returned to the second stage, and the second stage washing liquid was returned to the first stage. The residual chlorine content in the dechlorinated germanium slag was 0.9%. The first stage washing liquid was a high-chlorine washing liquid with a chlorine content of 119 g / L.

[0063] (2) Negative pressure distillation: The high-chlorine washing solution is subjected to negative pressure distillation at a temperature of 80℃, a pressure of 0.09MPa, and a time of 120min to obtain dilute hydrochloric acid with a mass fraction of 17% and negative pressure distillation residue with pH 2. The dilute hydrochloric acid enters the desorption enrichment step, and the negative pressure distillation residue enters the adsorption separation step.

[0064] The chlorine recovery rate in the water washing dechlorination-negative pressure distillation process is 94.6% (94.6% of the chlorine in the chlorine-containing germanium slag is converted into dilute hydrochloric acid product).

[0065] (3) After the chlorine-containing germanium slag that has been pretreated by water washing and dechlorination is mixed with the alkaline leaching solution of stage II, the alkaline leaching of stage I is carried out. The initial alkali concentration is 80 g / L, the reaction temperature is 60℃, the liquid-solid ratio is 5:1, and the time is 120 min. After the reaction, the liquid and solid are separated to obtain the alkaline leaching solution of stage I with a residual alkali concentration of 10 g / L and the alkaline leaching slag of stage I.

[0066] Step 2, Section II Alkali Immersion: The alkaline leaching residue from stage I was mixed with the adsorption solution and washing solution at a liquid-solid ratio of 7:1 and then subjected to alkaline leaching in stage II. Sodium hydroxide was added to make the initial alkali concentration of the reaction slurry 180 g / L. The leaching temperature was controlled at 70℃ and the leaching time was controlled at 60 min. After leaching, the liquid and solid were separated to obtain alkaline leaching solution and alkaline leaching residue from stage II. The residual germanium content of the alkaline leaching residue from stage II was 0.03%.

[0067] The alkaline leaching residue of stage II was washed by stirring and washing. During the stirring and washing process, the process water and the alkaline leaching residue of stage II were mixed at a liquid-solid ratio of 2:1 and then stirred and washed at 70°C for 60 minutes. After the reaction was completed, the washing liquid and the final leaching residue were obtained by liquid-solid separation.

[0068] The germanium leaching rate of the two-stage countercurrent alkaline leaching was 98.3%, and the germanium content of the alkaline leaching solution in stage I was 205 mg / L.

[0069] Step 3: Adsorption and separation The alkaline leaching solution from stage I was mixed with the residual liquid from negative pressure distillation to obtain a mixed solution with a pH of 9 and a germanium concentration of 536 mg / L. This mixed solution was then passed sequentially through three ion exchange columns connected in series at a flow rate of 2 BV. The ion exchange columns were filled with quaternary ammonium strong-base resin. The switching of the ion exchange columns and the opening of the adsorption path were controlled by adjusting the residual germanium concentration in the post-adsorption solution. The residual germanium concentration in the post-adsorption solution was controlled to be 4 mg / L. After the ion exchange resin reached saturation, the germanium-loaded resin entered the desorption enrichment process. The direct recovery rate of germanium during the adsorption separation process was 99.7%.

[0070] Step 4: Desorption and enrichment Using 17% hydrochloric acid (by mass) generated during negative pressure distillation as a desorbent, saturated germanium-loaded resin was desorbed, yielding a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin. The low-germanium solution was continuously evaporated and concentrated at 70℃ to obtain a high-germanium concentrate with a germanium concentration of 11 g / L. The high-germanium solution and the high-germanium concentrate were mixed, and concentrated hydrochloric acid was added until the hydrochloric acid concentration reached 36%. Then, direct chlorination distillation was performed at 85℃ for 4 hours, yielding 5N GeCl4 product and chlorination distillation residue. The residual germanium concentration in the distillation residue was 83 mg / L. The distillation residue was returned to the negative pressure distillation process. The direct recovery rate of germanium during the desorption and enrichment process reached 98.3%.

[0071] In this embodiment, the germanium recovery rate is 96.3% and the chlorine recovery rate is greater than 94.5% throughout the entire process.

[0072] Comparative Example 2 This comparative example uses the same raw materials as Example 3, and the alkalinity is the same in both alkaline leachings.

[0073] Step 1, Section I: Alkali Immersion (1) Water washing dechlorination pretreatment: The chlorine-containing germanium slag was washed at room temperature by a three-stage countercurrent washing method for 90 min. The third stage washing liquid was returned to the second stage, and the second stage washing liquid was returned to the first stage. The residual chlorine content in the dechlorinated germanium slag was 0.9%. The first stage washing liquid was a high-chlorine washing liquid with a chlorine content of 119 g / L.

[0074] (2) Negative pressure distillation: The high-chlorine washing solution is subjected to negative pressure distillation at a temperature of 80℃, a pressure of 0.09MPa, and a time of 120min to obtain dilute hydrochloric acid with a mass fraction of 17% and negative pressure distillation residue with pH 2. The dilute hydrochloric acid enters the desorption enrichment step, and the negative pressure distillation residue enters the adsorption separation step.

[0075] The chlorine recovery rate in the water washing dechlorination-negative pressure distillation process is 94.6% (94.6% of the chlorine in the chlorine-containing germanium slag is converted into dilute hydrochloric acid product).

[0076] (3) After the chlorine-containing germanium slag that has been pretreated by water washing and dechlorination is mixed with the alkaline leaching solution of the second stage and the alkaline solution is added, the first stage alkaline leaching is carried out. The initial alkaline concentration is 180 g / L, the reaction temperature is 60℃, the liquid-solid ratio is 5:1, and the time is 120 min. After the reaction is completed, the liquid and solid are separated to obtain the alkaline leaching solution of the first stage with a residual alkaline concentration of 112 g / L and the alkaline leaching slag of the first stage.

[0077] Step 2, Section II Alkali Immersion: The alkaline leaching residue from stage I was mixed with alkaline solution at a liquid-to-solid ratio of 7:1 and then subjected to alkaline leaching in stage II. The initial alkaline concentration of the reaction slurry was controlled at 180 g / L, the leaching temperature was 70℃, and the leaching time was 60 min. After leaching, the liquid and solid were separated to obtain alkaline leaching solution and alkaline leaching residue from stage II. The residual germanium content of the alkaline leaching residue from stage II was 0.064%.

[0078] The alkaline leaching residue of stage II was washed by stirring and washing. During the stirring and washing process, the process water and the alkaline leaching residue of stage II were mixed at a liquid-solid ratio of 2:1 and then stirred and washed at 70°C for 60 minutes. After the reaction was completed, the washing liquid and the final leaching residue were obtained by liquid-solid separation.

[0079] The germanium leaching rate was 93.4% in the two-stage countercurrent alkaline leaching. The germanium content in the mixture of the first-stage and second-stage alkaline leaching solutions was 77 mg / L.

[0080] Step 3: Adsorption and separation The first-stage alkaline leaching solution, the second-stage alkaline leaching solution, and the residual liquid from negative pressure distillation were mixed, and hydrochloric acid was added to adjust the pH to 9. The germanium concentration in the mixture was 127 mg / L. The mixture was passed sequentially through three ion exchange columns connected in series at a flow rate of 2 BV. The ion exchange columns were filled with quaternary ammonium strong base resin. The switching of ion exchange columns and the open-circuit operation of the adsorption liquid were achieved by controlling the residual germanium concentration in the post-adsorption liquid. The residual germanium concentration in the open-circuit adsorption liquid was controlled at 4 mg / L. After the ion exchange resin reached saturation, the germanium-loaded resin entered the desorption enrichment process. The direct recovery rate of germanium in the adsorption separation process was 68.3%.

[0081] Step 4: Desorption and enrichment Using 17% hydrochloric acid (by mass) generated during negative pressure distillation as a desorbent, saturated germanium-loaded resin was desorbed, yielding a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin. The low-germanium solution was continuously evaporated and concentrated at 70℃ to obtain a high-germanium concentrate with a germanium concentration of 11 g / L. The high-germanium solution and the high-germanium concentrate were mixed, and concentrated hydrochloric acid was added until the hydrochloric acid concentration reached 36%. Then, direct chlorination distillation was performed at 85℃ for 4 hours, yielding 5N GeCl4 product and chlorination distillation residue. The residual germanium concentration in the distillation residue was 83 mg / L. The distillation residue was returned to the negative pressure distillation process. The direct recovery rate of germanium during the desorption and enrichment process reached 97.2%.

[0082] In this embodiment, the germanium recovery rate throughout the entire process is 62.00%.

[0083] Because the alkali leaching concentrations were the same in both stages, and the alkali concentration in stage I was higher, the ion concentration in the reaction system was higher, and the solution was more viscous, which was not conducive to germanium leaching, the residual germanium content in the alkali leaching residue of stage II increased from 0.03% to 0.064%, and the germanium leaching rate of the two countercurrent alkali leaching stages decreased from 98.3% to 93.4%. At the same time, the germanium concentration in the alkaline leachate was diluted, decreasing from 205 mg / L to 77 mg / L, which increased the difficulty of subsequent recovery and treatment and the germanium recovery rate.

[0084] Since the alkali concentration of the alkaline leaching solution in stage I is increased from 10 g / L to 112 g / L, in order to meet the pH requirements of the ion exchange method, a large amount of hydrochloric acid is needed to adjust its pH to 9, which will introduce a large amount of chloride ions. This has an extremely adverse effect on the direct recovery rate of germanium in the adsorption and separation process, causing the direct recovery rate of germanium to decrease from 99.7% to 68.3%.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium, characterized in that, Includes the following steps, (1) After the pretreated chlorine-containing germanium slag is mixed with alkaline solution, the first stage of alkaline leaching is carried out. After the leaching slurry is separated into liquid and solid, the first stage alkaline leaching solution and the first stage alkaline leaching residue with a residual alkali concentration of 1-10 g / L are obtained. (2) After adjusting the alkaline leaching residue of section I, the alkaline leaching of section II is carried out. After liquid-solid separation of the leaching slurry, section II alkaline leaching solution and section II alkaline leaching residue are obtained. (3) The germanium is recovered by ion exchange from the alkaline leaching solution of step (1) I.

2. The method for recovering germanium and chlorine from chlorine-containing germanium slag during deep processing of germanium according to claim 1, characterized in that, Use the second-stage alkaline leaching solution for the first-stage alkaline leaching; control the amount of sodium hydroxide added in the second-stage alkaline leaching to ensure that the germanium residue in the second-stage alkaline leaching residue is less than 0.05%.

3. The method for recovering germanium and chlorine from chlorine-containing germanium slag during deep processing of germanium according to claim 1, characterized in that, For stage I alkaline leaching, the initial alkali concentration is 30–80 g / L, the reaction temperature is 60–80℃, the liquid-solid ratio is 5:1–8:1, and the time is 30–120 min. For stage II alkaline leaching, the initial alkali concentration is 120–180 g / L, the reaction temperature is 60–80℃, the liquid-solid ratio is 6:1–10:1, and the time is 30–120 min.

4. The method for recovering germanium and chlorine from chlorine-containing germanium slag during deep processing of germanium according to claim 1, characterized in that, Step (2) also includes washing the alkaline leaching residue of stage II. The germanium entrained in the alkaline leaching residue of stage II is transferred into the washing solution by rinsing or stirring, so as to obtain low germanium leaching final residue and washing solution.

5. The method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium according to any one of claims 1 to 4, characterized in that, The pretreatment mentioned in step (1) refers to washing away chlorine from the chlorine-containing germanium slag with water; the chlorine content of the chlorine-containing germanium slag after pretreatment is <1%; a high-chlorine washing solution is obtained after pretreatment; the high-chlorine washing solution is subjected to negative pressure distillation to obtain dilute hydrochloric acid and negative pressure distillation residue with pH 2-3.

6. The method for recovering germanium and chlorine from chlorine-containing germanium slag during deep processing of germanium according to claim 5, characterized in that, Hydrochloric acid solution was used as a desorbent to desorb the loaded ion exchange resin in step (3) to obtain a germanium-containing desorbent solution.

7. The method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium according to claim 6, characterized in that, Hydrochloric acid was added to the germanium-containing desorption solution for chlorination and distillation to obtain germanium tetrachloride product and chlorinated distillate.

8. The method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium according to claim 7, characterized in that, Desorption yields a high-germanium solution with a germanium concentration ≥5000 mg / L, a low-germanium solution with a germanium concentration <5000 mg / L, and regenerated resin; hydrochloric acid is added to the high-germanium solution with a germanium concentration ≥5000 mg / L for chlorination and distillation; the low-germanium solution is concentrated and then mixed with the high-germanium solution for chlorination and distillation.

9. The method for recovering germanium and chlorine from chlorine-containing germanium slag during deep processing of germanium according to claim 6, characterized in that, The residual liquid from the negative pressure distillation of the high-chlorine washing solution is returned to step (3) and mixed with the alkaline leaching solution of stage I. Germanium is recovered by ion exchange. The pH of the mixture of the alkaline leaching solution of stage I and the residual liquid from the negative pressure distillation is 7-9. The dilute hydrochloric acid obtained by the negative pressure distillation of the high-chlorine washing solution is used as a desorbent.

10. The method for recovering germanium and chlorine from chlorine-containing germanium slag in deep processing of germanium according to claim 5, characterized in that, The chlorine-containing germanium slag is subjected to 2-3 stages of countercurrent water washing with stirring at room temperature for 30-90 minutes. The washing liquid of the 3rd stage is returned to the 2nd stage, and the washing liquid of the 2nd stage is returned to the 1st stage. The washing liquid of the 1st stage is the high-chlorine washing liquid.

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