Method for simultaneously extracting germanium and indium from zinc sulfate solution containing germanium and indium

Abstract

The invention discloses a method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium, which comprises the following steps of: firstly, adding tartaric acid complexing germanium into a zinc sulfate leaching solution containing germanium and indium to obtain germanium tartrate, and then simultaneously extracting germanium and indium by using a kerosene mixed extracting agent of N235 and P204, then hydrochloric acid larger than 6N or a mixed solution of hydrochloric acid and chlorine salt is used for conducting reverse extraction on germanium and indium at the same time, after germanium and indium in reverse extraction liquid are enriched, chlorination of the reverse extraction liquid is conducted, germanium tetrachloride is distilled, hydrochloric acid is used for absorbing germanium tetrachloride, or purified water or dilute alkali liquor is used for absorbing and hydrolyzing germanium tetrachloride into germanium hydroxide or Ge02, and germanium is recycled through precipitation; the sponge indium in the distillation residual liquid is replaced by metal zinc or aluminum, so that the purposes of simplifying the process flow and improving the economic benefit are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of comprehensive recovery of rare and scattered metals, and specifically relates to a method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium, that is, using N 235 and P 204 The invention relates to a process for extracting germanium and indium from zinc sulfate leaching solution or other sulfuric acid solution containing germanium and indium simultaneously using a kerosene mixed extractant, and stripping germanium and indium simultaneously using hydrochloric acid or a mixed solution of hydrochloric acid chloride, and then separating germanium and indium by chlorination distillation of the chlorinated stripping solution. Background Art

[0002] Germanium and indium are both rare and dispersed metals, about 70% of which are associated with lead-zinc ores. In the process of lead-zinc hydrometallurgy, when using sulfuric acid to leach zinc oxide powder or high-pressure oxidation to leach zinc sulfide concentrate, germanium and indium enter the zinc sulfate leachate at the same time. When the content is low, it is generally pre-neutralized to pH = 4.8 to precipitate and enrich germanium and indium in the slag. Then, by leaching with sulfuric acid, the content of germanium in the leachate can be increased to more than 50 mg / L, and the content of indium can be increased to more than several hundred to 1000 mg / L. If the tannin precipitation method is used to extract and separate germanium and indium from the sulfuric acid solution containing germanium and indium, it must first be treated with P 204 The kerosene extractant extracts indium, and the residual solution of indium is then used to precipitate germanium with tannin. Otherwise, when tannin is used to precipitate germanium first, the tannin cannot completely precipitate indium, and only about 30% is precipitated in the tannin germanium residue and dispersed and lost. In addition, after tannin precipitates germanium, the solution contains tannic acid organic matter, which will cause P 204 Emulsion or third phase is produced during the extraction of indium, which affects the smooth extraction of indium.

[0003] Therefore, organic solvent extraction is often used to extract and separate germanium and indium from sulfuric acid leaching solutions containing both germanium and indium. The main extraction technology process currently used is N 235 Kerosene extractant first extracts germanium, and the residual germanium is then extracted with P 204 Extract indium with kerosene extractant, or first use P 204 Kerosene extractant extracts indium, and then N235 extracts germanium. Regardless of which comes first, they are extracted and stripped separately. The process is long, and many extraction, stripping equipment and auxiliary equipment are required. In addition, the stripped germanium liquid must be neutralized and hydrolyzed to obtain germanium concentrate, and then germanium tetrachloride is distilled. When the germanium-containing stripping liquid is neutralized and hydrolyzed, waste liquid mainly containing Na2S04 is produced, which needs to be treated.

[0004] Use P 204 _Hydroxamic acid or P 204 _ Hydroxamic acid kerosene extractant extracts germanium and indium from sulfuric acid leaching solution containing both germanium and indium. 235 and P 204 Like kerosene extractants, separate extraction and separate stripping must be performed. This is because P 204_When oxime acid mixed extractants are used to extract germanium, the P 204 Indium will also be extracted. When stripping with sulfuric acid, fluoride salt or other special solutions, germanium and indium will enter the stripping solution and need to be separated again. In addition, since germanium is extracted by forming a chelate, it is necessary to use a fluoride-containing solution. - Acidic solution or specific solution stripping, stripping difficulty is greater than N 235 The anion and cation combination extraction has more complicated technical processes and more difficult treatment of the three wastes.

[0005] Someone once used P 204 _Hydroxamic acid (H 106 Extractant) is used to extract germanium and indium from the sulfuric acid leaching solution at the same time, and then indium or germanium is stripped in stages with sulfuric acid of different concentrations. Since the stripping solution acid has the same properties but different concentrations, indium and germanium are contained in the stripping solution in each stage, and the complete separation and extraction cannot be carried out and fails. 204 _A similar situation also occurs with hydroxamic acid extractants. Therefore, the current process of extracting germanium and indium from acid leaching solutions containing both germanium and indium is to use separate extraction, separate stripping, acid-base neutralization and hydrolysis of the germanium stripping solution to precipitate germanium concentrate, and then the germanium concentrate is distilled into germanium tetrachloride. Summary of the invention

[0006] In order to overcome the many shortcomings of the above-mentioned technical process, the present invention proposes to add tartaric acid-complexed germanium to tartrate germanium in the zinc sulfate leachate containing germanium and indium at the same time, and then use N 235 and P 204 The germanium and indium are extracted simultaneously with kerosene mixed extractant, and then the germanium and indium are stripped simultaneously with hydrochloric acid greater than 6N or a mixture of hydrochloric acid and chloride salt. After the germanium and indium in the stripping solution are enriched, the stripping solution is subjected to chlorination distillation to obtain germanium tetrachloride, and the germanium tetrachloride is absorbed with hydrochloric acid, or absorbed and hydrolyzed with pure water or dilute alkali solution to obtain germanium hydroxide or GeO2 precipitation to recover germanium; the distillation residue is replaced with metal zinc or aluminum for sponge indium, thereby achieving the purpose of simplifying the process and improving economic benefits.

[0007] The technical solution of the present invention:

[0008] A method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium comprises the following steps:

[0009] Step 1. First, add tartaric acid to the zinc sulfate solution containing both germanium and indium at a ratio of tartaric acid / germanium = 5-8, stir to dissolve and mix evenly; then add 235 and P 204 The kerosene mixed extractant is used to simultaneously extract germanium and indium from the sulfuric acid solution; the extraction conditions are: the pH value of the sulfuric acid solution containing germanium and indium is 1-2, the extraction phase ratio of organic matter to water is 1 / 4-1 / 3, the extraction temperature is from room temperature to 50°C, and the extraction level is 4-6;

[0010] Step 2. The mixed extraction organic phase enriched with germanium and indium in step 1 is stripped with 8-9N hydrochloric acid solution or a mixed solution of hydrochloric acid chloride containing 200-250g / L of chloride ions and an acidity of 6-7N to obtain a chlorinated stripping solution containing both germanium and indium; the stripping ratio is organic / water = 1 / 2-1, the stripping temperature is room temperature or 20-30°C, and the stripping stage is 2;

[0011] Step 3. The stripping solution containing germanium and indium in step 2 is repeatedly returned for stripping, and after the germanium and indium are enriched to a certain content, the stripping solution is removed and placed in a distillation kettle, heated to 100±5°C, and subjected to chlorination distillation to obtain germanium tetrachloride distillate; the end point of the chlorination distillation is that Ge≤50mg / L in the distillation residue; the germanium tetrachloride obtained by distillation is absorbed and condensed into germanium tetrachloride liquid by 6N hydrochloric acid solution, or directly absorbed by pure water with a pH of about 7 or a sodium salt weak alkali solution with a pH of 8 to 10 to obtain a germanium hydrolyzate or GeO2 precipitate;

[0012] Step 4. The chlorinated distillation residual liquid in step 3 is replaced with a metal zinc plate or a metal aluminum plate for sponge indium; the replacement temperature is room temperature or 20-30° C.; the replacement end point is that the indium content of the liquid after replacement is ≤100 mg / L;

[0013] Step 5. The organic phase from which germanium and indium are removed by chlorination stripping in step 3 is washed 1 to 2 times at room temperature with a mixed solution of dilute sulfuric acid containing oxalic acid and then returned for extraction.

[0014] Furthermore, the N in step 1 235 and P 204 The kerosene mixed extractant is a 20-30% volume percent concentration of N 235 , the volume percentage concentration is 10-20% P 204 , a mixed extractant is prepared by mixing kerosene with a volume percentage of ≥50%; at the same time, the sulfuric acid solution containing germanium and indium has Ge ≥50mg / L and In ≥500mg / L; if the content is lower than the above, enrichment treatment is carried out before mixed extraction.

[0015] Furthermore, the hydrochloric acid and hydrochloric acid chloride mixed stripping solution of step 3 is repeatedly returned and used until the enriched germanium is ≥3 g / L and the enriched indium is ≥25 g / L, and then it can be removed and placed in a distillation kettle for chlorination distillation of germanium tetrachloride; the repeated return of the hydrochloric acid stripping solution requires the addition of hydrochloric acid to maintain a hydrochloric acid concentration of 7 to 9 N; the repeated return of the hydrochloric acid chloride mixed stripping solution requires the maintenance of a hydrochloric acid concentration of 6 to 7 N.

[0016] Furthermore, the mixed washing liquid of dilute sulfuric acid and oxalic acid in step 5 is a sulfuric acid solution containing 50-100 g / L sulfuric acid and 5% oxalic acid by mass, and the washing phase ratio is 1 / 4-1 / 3.

[0017] Working principle of the present invention:

[0018] 1. Adding tartaric acid to the sulfuric acid leaching solution containing germanium and indium can cause the germanium in the solution to undergo a complex reaction to generate Ge(C406H4) 2- The complex anion of indium does not react with tartaric acid and remains In3+. 235 After kerosene extraction agent is acidified with sulfuric acid, it changes into (R3NH + )(HS04 - ) ion association, where R3NH + It is a soft acid, and its hardness is similar to Ge(C406H4) 2- Soft bases are more compatible. 235 Only germanium tartrate anions are extracted, and indium cations are not extracted. 204 It is a cationic extractant, In 3+ Zn 2 + , Fe 2+ Etc. and P 204 The soft and hardness matching is given priority by P 204 Extraction. In the case of the present invention, the mixed extractant N 235 and P 204 It has the function of selectively extracting germanium complex anions and trivalent indium cations respectively, thus achieving the simultaneous extraction of germanium and indium. 204 The reason why oxime acid extractants can extract germanium and indium at the same time is that under high acidity conditions above 150g / L, germanium and indium are both in cationic state. Germanium forms a chelate with hydroxamic acid or hydroxamic acid and is extracted, while indium is extracted in cationic state. 204 Extraction. Since germanium forms a chelate with hydroxamic acid or hydroxamic acid in the organic phase, a high extraction efficiency can be achieved, but the difficulty of stripping is increased, and a special proprietary stripping agent or fluoride salt stripping agent is required for stripping, which brings greater difficulties to the subsequent processing of germanium and the treatment of three wastes.

[0019] 2. Germanium in high concentration hydrochloric acid or Cl - The main product in the system is germanium tetrachloride. Germanium tetrachloride is a neutral molecule with no charge and can release the N 235 The anion-cation association state of the extractant is stripped into the hydrochloric acid solution. It is common sense that indium can be stripped directly by hydrochloric acid above 6N. Therefore, it is relatively easy to strip germanium and indium at the same time with high-concentration hydrochloric acid or a mixed solution of hydrochloric acid and chloride salt. Since the boiling point of germanium tetrachloride is about 56°C, as long as the temperature of the stripping solution is controlled at room temperature not higher than 30°C, germanium tetrachloride mainly exists in the stripping solution in a liquid state with a larger specific gravity and is partially dissolved in the stripping solution.

[0020] 3. Place the low-temperature stripping solution in a distillation kettle and heat it to above 50°C, and the germanium tetrachloride will be distilled out in a gaseous state and separated from indium. The present invention adopts a distillation temperature of 100±5°C, and can distill out 99% of the germanium tetrachloride liquid and the germanium chloride dissolved in the stripping solution. The distilled gaseous germanium tetrachloride can be re-condensed into a liquid by introducing it into a hydrochloric acid solution above 6N through a pipeline; when introduced into pure water or weak alkaline water with a pH of 8 to 10, the germanium tetrachloride can be hydrolyzed and precipitated into germanium hydroxide or GeO2 to obtain a high-grade germanium concentrate. The absorption liquid mainly contains hydrochloric acid or chloride salt, which can be returned to prepare the stripping solution for use. The residual liquid of the chlorination distillation is at about the 6N constant boiling point of hydrochloric acid, and there will be no problem in replacing the indium therein with metallic zinc or aluminum. In addition, in order to reduce the arsenic trichloride that is evaporated with the germanium tetrachloride and affects the quality of the germanium concentrate, chlorine gas or KMnO4 can be added during the chlorination distillation to remove As 3+ Oxidized to As5 + It is not easy to be distilled out, and at the same time reduces the As in the distillation residue 3+ content, which is beneficial to the replacement of sponge indium.

[0021] 4. The mechanism of the organic phase of hydrochloric acid stripping germanium and indium is to wash and regenerate it with a mixture of dilute sulfuric acid and oxalic acid. The sulfuric acid can elute the chloride ions in the organic phase and remove N 235 It is converted into an association complex with hydrogen sulfate and regenerated. The chemical reaction equation is: (R3NH)+(Cl) - +H2S04→(R3NH)+(HS04) - +HCl. Oxalic acid regeneration P 204 It is common sense that the ability of the mixed extractant to simultaneously extract germanium and indium is restored after washing and regeneration.

[0022] The invention simplifies the technical process of extracting and separating germanium and indium from a sulfuric acid solution containing both germanium and indium to finally obtain a hydrolyzate of germanium and sponge indium; improves production efficiency, and reduces equipment investment and production costs. DETAILED DESCRIPTION

[0023] The present invention will be further described below by way of examples.

[0024] Embodiment: A method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium comprises the following steps:

[0025] Step 1. First, add tartaric acid to the sulfuric acid solution containing germanium and indium at a ratio of tartaric acid / germanium = 5-8, and stir to mix evenly; then 235 and P 204 The kerosene mixed extractant simultaneously extracts germanium and indium; the N 235 and P 204 The kerosene mixed extractant is N 235 Volume percentage concentration is 20-30%, P204 A mixed extractant prepared with a volume percentage concentration of 10-20% and a volume percentage of kerosene ≥50%;

[0026] The extraction conditions for the mixed extractant to simultaneously extract germanium and indium are as follows: the ratio of germanium to water is 1 / 4 to 1 / 3, the extraction temperature is from room temperature to 50° C., and the extraction level is 4 to 6;

[0027] Step 2. The mixed extraction organic phase enriched with germanium and indium in step 1 is stripped with pure hydrochloric acid or a mixed solution of hydrochloric acid containing chloride salt to obtain a chlorinated stripping solution containing germanium and indium at the same time; the pure hydrochloric acid stripping solution is a hydrochloric acid solution of 8-9N; the mixed stripping solution of hydrochloric acid and chloride salt contains Cl-200-250g / L, acidity is 6-7N, the stripping conditions are that the ratio of hydrogen to water is 1 / 2-1, the temperature is room temperature or 20-30°C, and the stripping level is 2 levels; the stripping solution is repeatedly returned and used until the first-level stripping solution contains germanium ≥3g / L and indium ≥25g / L, and then removed from the body (outside the stripping section) for treatment; when the hydrochloric acid stripping solution is repeatedly returned and used, hydrochloric acid must be supplemented to maintain the acidity of the stripping solution at 8-9N; when the mixed stripping solution of chloride salt and hydrochloric acid is repeatedly returned and used, the acidity must be maintained at 6-7N;

[0028] Step 3. The primary stripping solution removed from the body in step 2 is placed in a distillation kettle to perform chlorination distillation of germanium tetrachloride; the distilled germanium tetrachloride is absorbed and cooled with a 6N hydrochloric acid solution to obtain a germanium tetrachloride liquid, or absorbed and hydrolyzed with pure water or a weak alkaline solution of about pH=7 to obtain GeO2 or germanium hydroxide precipitate; the chlorination distillation condition is a distillation temperature of 100±5°C, and the distillation end point is that the residual liquid contains Ge≤50mg / L; the weak alkaline absorption liquid is a sodium salt solution prepared by NaOH or Na2C03, and the pH is 8-10;

[0029] Step 4. The chlorinated distillation residual liquid of step 3 is replaced with sponge indium by a metal zinc plate or an aluminum plate at room temperature, the replacement end point is that the liquid after replacement contains Ⅰ n ≤ 100 mg / L, and the replacement temperature is room temperature or 20-30°C;

[0030] Step 5. The organic phase from the chlorination stripping of germanium and indium in step 2 is washed 1-2 times with a mixture of dilute sulfuric acid and oxalic acid and then returned for extraction. The mixture of dilute sulfuric acid and oxalic acid is a sulfuric acid solution with a sulfuric acid concentration of 50-100 g / L and a mass percentage of oxalic acid of 5%; the washing phase ratio is 1 / 4-1 / 3, and the washing temperature is room temperature.

[0031] Example 1. The main chemical composition of the zinc sulfate leaching solution containing germanium and indium in a certain enterprise is: Ge47.4mg / L, In1.3g / L, Zn104g / L, H + 76g / L, tartaric acid / germanium = 5. Use 20% N 235 , 15%P 204, 65% kerosene mixed extractant for simultaneous extraction of germanium and indium. The extraction operation is: room temperature, oil / water ratio = 1 / 3, extraction level 3. The raffinate contains Ge8.4mg / L, In131mg / L. Extraction rate: germanium 82.3%, indium 90.1%. 8N hydrochloric acid is used for room temperature two-stage stripping, the stripping ratio oil / water = 1 / 2, the first stripping solution contains germanium 35.6mg / L, the stripping rate is 89.2%; the first stripping solution contains indium 1.03g / L, the stripping rate is 87.3%.

[0032] Example 2. The mixed extractant for stripping germanium and indium in Example 1 was subjected to two-stage washing and regeneration with a mixed solution of 100 g / L sulfuric acid and 5% oxalic acid, the washing and regeneration ratio was 1 / 3, and the temperature was room temperature. After washing and regeneration, the zinc sulfate leaching solution of Example 1 and the extraction, stripping, and washing and regeneration conditions of Example 1 were used to perform 5-stage extraction, two-stage stripping, and two-stage washing and regeneration. The extract residue contained 6.2 mg / L germanium, with an extraction rate of 93.5%, and the extract residue contained 98.5 mg / L In, with an extraction rate of 96.3%. The first-stage stripping solution contained 38.6 mg / L germanium, with a stripping rate of 92.5%; the first-stage stripping solution contained 1185 mg / L indium, with a stripping rate of 98.1%.

[0033] Example 3. The mixed extraction organic phase of Example 2 and the extraction, stripping, regeneration operating conditions and stripping solution were used repeatedly to operate the zinc sulfate leaching solution containing germanium and indium in Example 1 for 30 times. The raffinate contained an average of 8.75 mg / L of germanium and 108.5 mg / L of indium, with an average extraction rate of 90.1% and an average extraction rate of 94.5% of indium. The first stripping solution contained a total of 1.12 g / L of germanium and 35.6 g / L of indium. The stripping solution was supplemented with 12N hydrochloric acid for a total of 8 times, 10 mL each time.

[0034] Example 4. Take 200mL of the primary hydrochloric acid stripping solution of Example 3 and perform chlorination distillation under laboratory conditions. The distillation temperature is 95-100°C, the distillation time is 30 minutes, and the germanium tetrachloride is absorbed with pure distilled water. After the distillation, 150mL of distillation residue is obtained. The distilled absorption liquid is turbid. After standing for 1 hour, there is a white precipitate. After filtering, drying and testing, the germanium concentrate grade is 25.3%. The distillation residue contains 295.5mg / L of germanium and 42.5g / L of indium. The distillation rate of germanium tetrachloride is more than 99%, and the residual liquid contains 42.5g / L of indium. It has been enriched to a certain extent, which is conducive to the replacement of sponge indium.

[0035] The method for simultaneously extracting germanium and indium from other sulfuric acid solutions containing germanium and indium is also as above. The present invention simplifies the technical process of extracting and separating germanium and indium from sulfuric acid solutions containing both germanium and indium, and finally obtaining the hydrolyzate of germanium and sponge indium; improves production efficiency, and reduces equipment investment and production costs.

[0036] The above examples are only used to further illustrate the present invention, and the present invention is not limited thereto.

Claims

1. A method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium, characterized in that: The following steps are involved: Step 1. First, add tartaric acid to the zinc sulfate solution containing both germanium and indium at a ratio of tartaric acid / germanium = 5-8, stir to dissolve and mix evenly; then add 235 and P 204 The kerosene mixed extractant is used to simultaneously extract germanium and indium from the sulfuric acid solution; the extraction conditions are: the pH value of the sulfuric acid solution containing germanium and indium is 1-2, the extraction phase ratio of organic matter to water is 1 / 4-1 / 3, the extraction temperature is from room temperature to 50°C, and the extraction level is 4-6; Step 2. The mixed extraction organic phase enriched with germanium and indium in step 1 is stripped with 8-9N hydrochloric acid solution or a mixed solution of hydrochloric acid chloride containing 200-250g / L of chloride ions and an acidity of 6-7N to obtain a chlorinated stripping solution containing both germanium and indium; the stripping ratio is organic / water = 1 / 2-1, the stripping temperature is room temperature or 20-30°C, and the stripping stage is 2; Step 3. The stripping solution containing germanium and indium in step 2 is repeatedly returned for stripping, and after the germanium and indium are enriched to a certain content, the stripping solution is removed and placed in a distillation kettle, heated to 100±5°C, and subjected to chlorination distillation to obtain germanium tetrachloride distillate; the end point of the chlorination distillation is that Ge≤50mg / L in the distillation residue; the germanium tetrachloride obtained by distillation is absorbed and condensed into germanium tetrachloride liquid by 6N hydrochloric acid solution, or directly absorbed by pure water with a pH of about 7 or a sodium salt weak alkali solution with a pH of 8 to 10 to obtain a germanium hydrolyzate or GeO2 precipitate; Step 4. The chlorinated distillation residual liquid in step 3 is replaced with a metal zinc plate or a metal aluminum plate with the sponge indium; the replacement temperature is room temperature or 20-30° C.; the replacement end point is that the indium content of the liquid after the replacement is ≤100 mg / L; Step 5. The organic phase from which germanium and indium are removed by chlorination stripping in step 3 is washed 1 to 2 times at room temperature with a mixed solution of dilute sulfuric acid containing oxalic acid and then returned for extraction.

2. A method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium as claimed in claim 1, characterized in that: N of step 1 235 and P 204 The kerosene mixed extractant is a 20-30% volume percent concentration of N 235 , the volume percentage concentration is 10-20% P 204 , a mixed extractant is prepared by mixing kerosene with a volume percentage of ≥50%; at the same time, the sulfuric acid solution containing germanium and indium has Ge ≥50mg / L and In ≥500mg / L; if the content is lower than the above, enrichment treatment is carried out before mixed extraction.

3. A method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium as claimed in claim 1, characterized in that: The hydrochloric acid and hydrochloric acid chloride mixed stripping solution of step 3 is repeatedly returned and used until the enriched germanium is ≥3g / L and the enriched indium is ≥25g / L, and then it can be removed and placed in a distillation kettle for chlorination distillation of germanium tetrachloride; the hydrochloric acid stripping solution needs to be repeatedly returned and used to supplement hydrochloric acid to maintain a hydrochloric acid concentration of 7-9N; the hydrochloric acid chloride mixed stripping solution needs to be repeatedly returned and used to maintain a hydrochloric acid concentration of 6-7N.

4. A method for simultaneously extracting germanium and indium from a zinc sulfate solution containing germanium and indium as claimed in claim 1, characterized in that: The mixed washing liquid of dilute sulfuric acid and oxalic acid in step 5 is a sulfuric acid solution containing 50-100 g / L sulfuric acid and 5% oxalic acid by mass, and the washing phase ratio is sulfuric acid / water = 1 / 4-1 / 3.