Method for recovering germanium and regenerating mixed acid from zone-melting germanium ingot mixed acid cleaning solution

Abstract

The invention relates to a method for recovering germanium and regenerating mixed acid from zone-melting germanium ingot mixed acid cleaning fluid. The method comprises the following steps: (1) adding concentrated sulfuric acid with the concentration of 98% into germanium-containing fluorine-containing waste acid, and distilling to obtain germanium-containing concentrated liquor and regenerated mixed acid; new acid is added into the regenerated mixed acid, the ratio of hydrofluoric acid to nitric acid in the new acid is 1: 3, and the new acid is used for cleaning the zone-melting germanium ingot; (2) when F <-> in the germanium-containing concentrated liquor is greater than or equal to 0.5 g / L, returning to the step (1), continuously adding concentrated sulfuric acid with the concentration of 98%, and then distilling until F <-> in the germanium-containing concentrated liquor is less than 0.5 g / L; and (3) when F <-> in the germanium-containing concentrated liquor is less than 0.5 g / L, adding industrial hydrochloric acid into the germanium-containing concentrated liquor, and distilling to obtain a germanium tetrachloride product. According to the scheme provided by the invention, the germanium in the germanium-containing fluorine-containing waste acid is recovered, the process is short, the operation is simple and convenient, and the acid can be recycled.

Description

Technical Field

[0001] The present application relates to the technical field of hydrometallurgy, and in particular to a method for recovering germanium and regenerating mixed acid from a mixed acid cleaning solution of a zone melting germanium ingot. Background Art

[0002] In the production process of zone melting germanium ingots, the zone melting germanium ingots are cleaned with a mixed acid of analytical pure hydrofluoric acid and nitric acid in a ratio of 1:3, and the scum and oxide film attached to the surface of the zone melting germanium ingots are corroded and cleaned to remove them, so that the appearance of the zone melting germanium ingots presents a bright silver-gray luster, and the purity of the product is also improved. The waste acid obtained after cleaning generally contains 16g / L~20g / L of germanium and 9~10g / L of fluorine. The germanium in the waste acid needs to be further recovered, but the residual hydrofluoric acid in the waste acid is extremely corrosive to the enamel still, enamel pipes and titanium accessories, and the germanium contained therein cannot be directly extracted by acid distillation.

[0003] In the prior art, for the treatment of the above-mentioned germanium-containing waste acid, publication number CN201811059018.3 discloses a "Process for Recovering Germanium from Waste Acid from Deep Processing of Germanium Wafers", which includes the following steps: step S10, pre-treating the waste acid from deep processing of germanium wafers to remove fluorine and adjusting the pH value to obtain an alkaline germanium-containing solution; step S20, filtering the alkaline germanium-containing solution through a nanofiltration membrane, and filtering the alkaline germanium-containing solution through the nanofiltration membrane to separate the alkaline germanium-containing solution into a permeate that passes through the nanofiltration membrane and a retentate that does not pass through the nanofiltration membrane; step S30, evaporating and concentrating the permeate, cooling and crystallizing to obtain sodium nitrate crystals, and recycling the cooled mother liquor to the pH value adjustment section in step S10; evaporating and crystallizing the retentate to obtain a germanium concentrate, and recovering germanium from the germanium concentrate through chlorination distillation.

[0004] Although this method can recover germanium, the method requires at least the following steps from waste acid to germanium: pre-treatment defluorination, sodium hydroxide pH adjustment, nanofiltration of alkaline germanium-containing solution, evaporation crystallization of retentate, evaporation crystallization, and finally chlorination distillation of germanium concentrate to recover germanium. At the same time, the permeate needs to be evaporated, concentrated and cooled for crystallization. As can be seen from the above description, the method has lengthy steps and complicated procedures.

[0005] Therefore, for the treatment of germanium-containing waste acid, how to provide a method with a short process and simple operation on the basis of recovering germanium has always been a technical problem to be solved urgently by those skilled in the art. Summary of the invention

[0006] The present application provides a method for recovering germanium from a mixed acid cleaning liquid of a zone melting germanium ingot and regenerating the mixed acid. The method not only recovers germanium from germanium-containing and fluorine-containing waste acid, but also has a short process and simple operation, and can realize the recycling of the acid.

[0007] The present application provides a method for recovering germanium and regenerating mixed acid from a mixed acid cleaning solution of a zone melting germanium ingot, comprising the following steps:

[0008] (1) adding concentrated sulfuric acid with a concentration of 98% to the germanium-containing and fluorine-containing waste acid, and then distilling to obtain a germanium-containing concentrated solution and a regenerated mixed acid;

[0009] (2) When F in the germanium-containing concentrated solution - ≥0.5g / L, return to step (1), continue to add 98% concentrated sulfuric acid, and then distill until F in the germanium-containing concentrated solution is - <0.5g / L;

[0010] (3) When F in the germanium-containing concentrated solution - When the concentration of germanium is less than 0.5 g / L, industrial hydrochloric acid is added to the germanium-containing concentrated solution for distillation to obtain germanium tetrachloride product.

[0011] Optionally, in step (1), the volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid is 1 to 3:5.

[0012] Optionally, in step (1), the volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid is 1:2.

[0013] Optionally, in step (1), the germanium content of the germanium-containing and fluorine-containing waste acid is 16 g / L to 20 g / L, and the fluorine content is 9 to 10 g / L.

[0014] Optionally, in step (3), the volume ratio of the germanium-containing concentrated solution to industrial hydrochloric acid is 2:5-8.

[0015] Optionally, in step (3), the volume ratio of the germanium-containing concentrated solution to industrial hydrochloric acid is 2:8.

[0016] Optionally, new acid is added to the regenerated mixed acid in step (1), wherein the ratio of hydrofluoric acid to nitric acid is 1:3, and then used to clean the zone melting germanium ingot.

[0017] Mechanism of this application:

[0018] After the mixed acid cleaning liquid cleans the zone melting germanium ingot, the generated germanium-containing fluorine waste liquid still contains high contents of HNO3 and HF. Taking advantage of the physical properties of HNO3 and HF, which have high vapor pressure and are easily volatile when heated, the high boiling point acid is used to replace the low boiling point acid to remove the F in the mixed acid cleaning liquid. - , add concentrated H2SO4 to the germanium-containing and fluorine-containing waste liquid, and then use distillation to make the HNO3 and HF in the system escape as gases, and after condensation, obtain regenerated mixed acid and germanium-containing concentrated liquid; add industrial hydrochloric acid to the germanium-containing concentrated liquid and then distill it to produce GeCl4, thereby realizing the recovery of germanium.

[0019] The embodiment of the present invention provides a method for recovering germanium and regenerating mixed acid from a mixed acid cleaning solution of a zone melting germanium ingot, which has at least the following beneficial effects:

[0020] 1. Compared with the prior art, the method provided by the present application has a short process and is easy to operate. By mixing germanium-containing fluorine-containing waste acid with 98% concentrated sulfuric acid and then distilling it, and then mixing the obtained germanium-containing concentrated solution with industrial hydrochloric acid and then distilling it, germanium can be recovered in the form of GeCl4, and the process is simple;

[0021] 2. The reagents added are concentrated sulfuric acid and industrial hydrochloric acid with a concentration of 98%, and the reagents are easy to obtain;

[0022] 3. In the present application, new acid is added to the regenerated mixed acid obtained after distillation, and the ratio of hydrofluoric acid to nitric acid in the new acid is 1:3, so that the regenerated mixed acid can be reused to achieve the cleaning of the zone melting germanium ingot. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0024] Figure 1 It is the process flow chart of this application. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0026] Example 1

[0027] In the production process of zone melting germanium ingots, analytical pure hydrofluoric acid and nitric acid are mixed in a ratio of 1:3 to clean the zone melting germanium ingots. - The content is 9.75g / L, the Ge content is 16.44g / L. When the amount of 98% concentrated sulfuric acid added is different, after distillation for 1 hour at a temperature of 100°C and a pressure of 2-5kpa, the contents of germanium and F- in the germanium-containing concentrated solution are as shown in the following table.

[0028]

[0029] It can be seen from the table that under the same distillation time, the F -The content decreases with the increase of concentrated sulfuric acid. If the amount of concentrated sulfuric acid is increased, F - The content of F in the germanium-containing concentrated solution changes less and less; when the volume ratio of concentrated sulfuric acid to waste acid containing germanium and fluorine is 1:2 and 4:5, - The content of germanium is less than 0.5g / L, and industrial hydrochloric acid can be directly added for distillation, wherein the volume ratio of the germanium-containing concentrated solution to the industrial hydrochloric acid is 2:8, the distillation temperature is 70-85°C, the pressure is 5-10kpa, and the distillation time is 35-45 minutes, and the germanium tetrachloride product is obtained, thereby realizing the recovery of germanium. However, in order to save costs and reduce the amount of concentrated sulfuric acid, the present application selects a volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid of 1:2 as the optimal volume ratio.

[0030] In addition, during the distillation process, since the amount of water evaporated is greater than the amount of concentrated sulfuric acid added, it can be seen from the table that when the volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid is 1:2, the germanium content changes from the original 16.44g / L to 22.50g / L, achieving the concentration of germanium.

[0031] Example 2

[0032] On the basis of Example 1, when the volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid is 1:2, the obtained germanium-containing concentrated solution is added with different amounts of industrial hydrochloric acid for distillation, the distillation temperature is 70-85°C, the pressure is 5-10kPa, and the distillation time is 40-45 minutes. Finally, the effect of different volume ratios of germanium-containing concentrated solution to industrial hydrochloric acid on the direct recovery of germanium is obtained.

[0033]

[0034] It can be seen from the table that when the amount of germanium-containing concentrated solution remains unchanged, as the amount of industrial hydrochloric acid added gradually increases, the direct recovery rate of germanium gradually increases. When the volume ratio of the germanium-containing concentrated solution to the industrial hydrochloric acid is 2:8, the direct recovery rate of germanium is 97.9%. After continuing to add hydrochloric acid, the direct recovery rate of germanium does not change much. Therefore, the optimal volume ratio of the germanium-containing concentrated solution to the industrial hydrochloric acid is 2:8.

[0035] Example 3

[0036] In the production process of zone melting germanium ingots, a mixed acid of analytically pure hydrofluoric acid and nitric acid at a ratio of 1:3 is used to clean the zone melting germanium ingots to obtain germanium-containing and fluorine-containing waste acid, of which F - The content of F is 9.75 g / L and the content of Ge is 16.44 g / L. When the volume ratio of 98% concentrated sulfuric acid to the mixed acid is 1:2, 98% concentrated sulfuric acid is added to the germanium-containing fluorine-containing waste acid for distillation. The distillation temperature is 100°C, the pressure is 2-5 kPa, and the distillation time is 45 minutes. The F content of the obtained germanium-containing concentrated solution is 9.75 g / L and the Ge content is 16.44 g / L. - The content is 0.63g / L, the Ge content is 22.61g / L;

[0037] Because F - The content is 0.63g / L≥0.5g / L, so continue to add an appropriate amount of 98% concentrated sulfuric acid to the germanium-containing concentrated solution for distillation. The distillation temperature is 100℃, the pressure is 2-3kpa, and the distillation time is 55 minutes. The F content in the obtained germanium-containing concentrated solution is - The content is 0.45g / L<0.5g / L, the Ge content is 22.53g / L,

[0038] Industrial hydrochloric acid is added to the germanium-containing concentrated solution, the volume ratio of the germanium-containing concentrated solution to the industrial hydrochloric acid is 2:8, and distillation is performed at a distillation temperature of 70-85° C., a pressure of 5-10 kPa, and a distillation time of 40-45 minutes to obtain a germanium tetrachloride product.

[0039] According to chemical analysis, the direct recovery rate of germanium is 97.8%.

[0040] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for recovering germanium and regenerating mixed acid from a mixed acid cleaning solution of a zone melting germanium ingot, characterized in that: The following steps are involved: (1) adding concentrated sulfuric acid with a concentration of 98% to the germanium-containing and fluorine-containing waste acid, and then distilling to obtain a germanium-containing concentrated solution and a regenerated mixed acid; (2) When F in the germanium-containing concentrated solution - ≥0.5g / L, return to step (1), continue to add 98% concentrated sulfuric acid, and then distill until F in the germanium-containing concentrated solution is - <0.5g / L; (3) When F in the germanium-containing concentrated solution - When the concentration of germanium is less than 0.5 g / L, industrial hydrochloric acid is added to the germanium-containing concentrated solution for distillation to obtain germanium tetrachloride product.

2. The method according to claim 1, characterized in that In the step (1), the volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid is 1-3:

5.

3. The method according to claim 2, characterized in that In the step (1), the volume ratio of concentrated sulfuric acid to germanium-containing and fluorine-containing waste acid is 1:

2.

4. The method according to claim 1, characterized in that In the step (1), the germanium content of the germanium-containing and fluorine-containing waste acid is 16 g / L to 20 g / L, and the fluorine content is 9 to 10 g / L.

5. The method according to claim 3, characterized in that: In the step (3), the volume ratio of the germanium-containing concentrated solution to the industrial hydrochloric acid is 2:5-8.

6. The method according to claim 5, characterized in that In the step (3), the volume ratio of the germanium-containing concentrated solution to industrial hydrochloric acid is 2:

8.

7. The method according to claim 1, characterized in that Add new acid to the regenerated mixed acid in step (1), wherein the ratio of hydrofluoric acid to nitric acid is 1:3, and then use it to clean the zone melting germanium ingot.

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