Process for the sulphidic leaching of germanium from germanium-containing fumes

Abstract

The application discloses a method for recovering germanium from germanium-containing fume by sulfuration leaching, which comprises the following steps: primary sulfuration leaching, secondary sulfuration leaching, germanium deposition by magnesium sulfate, and oxidizing roasting to obtain germanium oxide concentrate. The germanium-containing fume is leached by a sulfuration agent, so that the germanium is enriched without using expensive tannin or tannin extract commonly used in the prior art, and the production cost of germanium recovery is reduced. The method has the advantages of simple process, low production cost and suitability for large-scale production, and provides a new method for recovering germanium from germanium-containing materials.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for leaching germanium-containing fume, in particular to a method for leaching germanium in germanium-containing fume. BACKGROUND

[0002] Germanium is a typical scattered metal, and its content in the earth's crust is about 0.0007%. Germanium has the chemical properties of being stone-loving, sulfur-loving, iron-loving and organic matter-loving, and there are basically no independent germanium-rich ore deposits in nature. Germanium is often associated with sulfide lead, zinc, copper, silver and gold deposits and some specific coal mines. The global germanium resources are relatively scarce, and the proven germanium reserves in the world are only 8600 tons. There are about 35 proven germanium ore deposits in China, with reserves of about 3500 tons and prospective reserves of about 9600 tons, mainly distributed in Yunnan, Inner Mongolia and Guangdong, etc. Among them, the germanium resources in Yunnan province account for 33.77% of the national reserves. Germanium is an important semiconductor material, and has wide and important applications in the fields of semiconductors, aerospace measurement and control, nuclear physics detection, optical fiber communication, infrared optics, solar cells, chemical catalysts, biomedicine, etc. At present, the raw materials for germanium extraction mainly include germanium-containing fume produced by coal combustion, germanium concentrate recovered in heavy non-ferrous metal smelting process and germanium-containing waste produced in semiconductor device production, etc. The germanium recovery process is mainly wet process supplemented by fire process.

[0003] CN110819828A discloses a method for recovering germanium dioxide from germanium-containing fume, which proposes to recover germanium dioxide by filtering, purifying and precipitating after two-stage alkali leaching of germanium-containing fume. The germanium recovery rate can reach more than 90%, but the recovery process will produce alkaline wastewater, causing secondary pollution and increasing the recovery cost.

[0004] CN102181653A discloses a method for recovering germanium from germanium-containing fume, which proposes to prepare germanium dioxide by chlorination distillation of the concentrated solution after twice sulfuric acid leaching, twice sodium hydroxide leaching, neutralization of the leaching solution to pH 5.0-5.5, evaporation concentration of the neutralization solution. The germanium recovery rate can reach more than 93%, but the process flow is long, the energy consumption is large, and a large amount of acidic and alkaline wastewater will be produced.

[0005] CN102345017A discloses a method for recovering germanium from germanium fume by microwave heating and alkali leaching, which proposes to recover germanium from germanium-containing fume by microwave heating to 500℃ and hot water leaching after mixing with sodium hydroxide, but this method has the disadvantages of high alkali consumption, high energy consumption and high equipment investment.

[0006] CN114921664A discloses a method for extracting germanium from low-grade germanium concentrate, which adopts a three-stage leaching method to extract low-grade germanium concentrate (Ge≤1%), that is, after the low-grade germanium concentrate is leached twice by sodium sulfide solution, it is leached once by sulfuric acid-ammonium fluoride solution, the first sodium sulfide leaching solution and the third sulfuric acid leaching solution are mixed, the pH of the solution is adjusted to 3-4 by the leaching solution, iron trichloride solution is added to precipitate germanium, and the pH value is adjusted to alkaline by ammonia solution to precipitate and recover germanium, and then the obtained germanium-containing precipitate is calcined at 500 DEG C to obtain high-grade germanium concentrate, and the second sodium sulfide leaching solution is used as the first leaching solution in the next leaching. The method has a long process for treating germanium concentrate, and toxic hydrogen sulfide gas with the smell of rotten egg is generated when the first sodium sulfide leaching solution and the third sulfuric acid leaching solution are mixed, and the sodium sulfide is only partially reused, resulting in high germanium recovery cost.

[0007] According to the current situation, most of the recovery and industrial application of germanium-containing dust is treated by acid method or acid-alkali combined method, and the subsequent germanium recovery is carried out, in the acid recovery, tannic acid or tannin is mainly used for precipitation and enrichment, magnesium sulfate is used for precipitation in alkali leaching solution to obtain germanium concentrate, or extraction or ion exchange resin is used for germanium recovery, these methods generally have problems of long germanium recovery process, high cost, large pollution of acid or alkaline wastewater, etc. SUMMARY

[0008] The technical problem to be solved by the present application is to overcome the above-mentioned defects existing in the prior art, and to provide a method for leaching germanium from germanium-containing dust by sulfuration, which is simple in process and low in production cost.

[0009] The technical solution adopted by the present application to solve the technical problem is as follows: a method for leaching germanium from germanium-containing dust by sulfuration, comprising the following steps:

[0010] (1) first sulfuration leaching: germanium-containing dust is reacted with sulfide solution, solid-liquid separation is carried out, and first leaching solution and first leaching residue are obtained;

[0011] (2) second sulfuration leaching: the first leaching residue is reacted with persulfate solution, solid-liquid separation is carried out, and second leaching solution and second leaching residue are obtained;

[0012] (3) germanium precipitation by magnesium sulfate: germanium is precipitated by adding magnesium sulfate to the first leaching solution and / or the second leaching solution, solid-liquid separation is carried out, and germanium precipitation solution and germanium precipitation residue are obtained;

[0013] (4) oxidation roasting: the germanium precipitation residue is roasted to obtain germanium oxide concentrate.

[0014] By using the above technical solution, germanium is leached from germanium-containing dust by using sulfuration agent, which avoids the use of expensive tannic acid or tannin in the prior art to enrich germanium, and reduces the production cost of germanium recovery.

[0015] Preferably, the sulfide in the sulfide solution in step (1) is sodium sulfide and / or potassium sulfide.

[0016] By using the above technical solution, a common sulfidizing agent is used, and production cost can be saved.

[0017] Preferably, the persulfide in the persulfide solution in step (2) is one of sodium persulfate, potassium persulfate, and ammonium persulfate, or a mixture of two or more thereof.

[0018] By using the above technical solution, a common sulfidizing agent is used, and production cost can be saved.

[0019] Preferably, in step (1), the S2- in the sulfide solution is 40-100 g / L. 2- The ratio of the germanium content in the germanium-containing fume to the content of the germanium-containing fume is 1-2 mol:1 g.

[0020] By using the above technical solution, the production cost is low, and the leaching effect is good.

[0021] Preferably, in step (1), the concentration of the sulfide solution is 40-100 g / L.

[0022] By using the above technical solution, the production cost is low, and the leaching effect is good.

[0023] Preferably, in step (1), the reaction temperature is 40-70°C.

[0024] By using the above technical solution, the production cost is low, and the leaching effect is good.

[0025] Preferably, in step (1), the reaction time is 1-3 h.

[0026] By using the above technical solution, the leaching effect is good.

[0027] Preferably, in step (1), stirring is also performed during the reaction.

[0028] The stirring speed can be selected according to the actual stirrer, as long as the reactants can be fully mixed.

[0029] By using the above technical solution, the leaching effect is good.

[0030] Preferably, in step (2), the S2- in the persulfide solution is 40-100 g / L. 2- The ratio of the germanium content in the germanium-containing fume to the content of the germanium-containing fume is 0.3-0.6 mol:1 g.

[0031] By using the above technical solution, the production cost is low, and the leaching effect is good.

[0032] Preferably, in step (2), the concentration of the persulfate solution is 20-50 g / L.

[0033] By adopting the above technical scheme, the production cost is low, and the leaching effect is good.

[0034] Preferably, in step (2), the reaction temperature is 40-60℃.

[0035] By adopting the above technical scheme, the production cost is low, and the leaching effect is good.

[0036] Preferably, in step (2), the reaction time is 1-3h.

[0037] By adopting the above technical scheme, the leaching effect is good.

[0038] Preferably, in step (2), stirring is also carried out during the reaction.

[0039] The stirring speed can be selected according to the actual situation of the stirrer, as long as the reactants can be fully mixed.

[0040] By adopting the above technical scheme, the leaching effect is good.

[0041] Preferably, in step (3), the amount of magnesium sulfate used is 5-8 times the content of germanium in the solution in terms of molar amount.

[0042] By adopting the above technical scheme, the germanium precipitation effect is good.

[0043] Preferably, in step (3), the temperature during the germanium precipitation process is 30-50℃.

[0044] By adopting the above technical scheme, the production cost is low, and the germanium precipitation effect is good.

[0045] Preferably, in step (3), the reaction time is 1-2h.

[0046] By adopting the above technical scheme, the germanium precipitation effect is good.

[0047] Preferably, in step (4), the calcination temperature is 800-1000℃.

[0048] By adopting the above technical scheme, the sulfide can be fully converted into oxide.

[0049] Preferably, in step (4), the calcination time is 3-5h.

[0050] By adopting the above technical scheme, the sulfide can be fully converted into oxide.

[0051] Preferably, the obtained post-germanium precipitation solution is supplemented with sulfide after step (3), and is returned to step (1) to be used as a sulfide solution.

[0052] By adopting the technical scheme, the production material can be recycled, and the small amount of germanium element remaining in the post-germanium precipitation solution can continue to be precipitated in the next germanium precipitation process.

[0053] The principle of the present application is as follows:

[0054] In step (1), the sulfide preparation solution is used to leach the germanium-containing fume and perform sulfidation transformation, and after liquid-solid separation, a primary thio-germanate leaching solution containing germanium and a primary leaching residue are obtained, and the germanium in the primary leaching residue mainly exists in the form of GeS.

[0055] The main reaction equation involved in step (1) is as follows:

[0056] GeO2+3S 2- +2H2O=[GeS3] 2- +4OH - ;

[0057] GeO+S 2- +H2O=GeS↓+2OH - ;

[0058] GeO2+2S 2- +2H2O=GeS2↓+4OH - ;

[0059] GeS2+S 2- =[GeS3] 2- 。

[0060] In step (2), the leaching residue obtained in step (1) is leached by a persulfide solution, and after liquid-solid separation, a secondary thio-germanate leaching solution and a secondary leaching residue are obtained, and the germanium in the primary leaching residue is also converted into a soluble form.

[0061] The main reaction equation involved in step (2) is as follows:

[0062] GeS+S2 2- =[GeS3] 2- 。

[0063] In step (3), magnesium sulfate is added to the germanium-containing primary and secondary leaching solutions obtained in steps (1) and (2) to precipitate germanium, and after liquid-solid separation, thio-germanate magnesium precipitate and post-germanium precipitation solution are obtained, and the magnesium ions in the magnesium sulfate participate in the chemical reaction and are precipitated as thio-germanate magnesium.

[0064] The main reaction equation involved in step (3) is as follows:

[0065] [GeS3]2- +Mg 2+ =MgGeS3↓.

[0066] The magnesium germanium sulfide obtained in step (3) is dried and then oxidized and roasted to obtain germanium oxide concentrate in step (4).

[0067] The main reaction equation involved in step (4) is as follows:

[0068] 2MgGeS3+9O2=2MgGeO3+6SO2↑.

[0069] The germanium grade of the obtained germanium oxide concentrate is 20-25%. The germanium oxide concentrate obtained can be separated from the impurity magnesium in the concentrate by chlorination distillation and other existing technologies, and then the germanium is recovered.

[0070] The present application is based on the mechanism that germanium can form water-soluble polysulfides, i.e., germanium sulfide, while most metal sulfides are insoluble precipitates. 2- The present application realizes the targeted separation of germanium. Under certain conditions, the present application realizes the efficient separation and recovery of germanium through one-time sulfidation leaching and sulfidation transformation, secondary leaching, germanium precipitation from leaching solution, and oxidation roasting, and has the advantages of short recovery process, low production cost, and suitability for industrial production.

[0071] Advantages of the present application:

[0072] (1) The present application uses a sulfidation agent to leach germanium-containing fumes, which avoids the use of expensive tannin or tannin extract to enrich germanium in the prior art, and reduces the production cost of germanium recovery.

[0073] (2) The present application has the advantages of simple process, low production cost, and suitability for large-scale production, and provides a new method for the recovery of germanium from germanium-containing materials. BRIEF DESCRIPTION OF DRAWINGS

[0074] Figure 1 is a process flow diagram of the method for leaching germanium from germanium-containing fumes in Example 1 of the present application. DETAILED DESCRIPTION

[0075] The present application will be further described below in conjunction with the examples and drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and do not limit the present application. The drawings are used to provide further understanding of the present application, and constitute a part of the specification, and are used to explain the present application together with the embodiments of the present application, and do not constitute a limitation on the present application.

[0076] The raw materials used in the embodiments of the present application are all obtained through conventional commercial channels.

[0077] Example 1

[0078] The germanium-containing flue dust used in this embodiment has the following composition listed in Table 1 below.

[0079] Table 1. Composition of germanium-containing dust in Example 1

[0080]

[0081] The process flow of the method for sulfidation leaching of germanium from germanium-containing dust in this embodiment is as follows: Figure 1 As shown.

[0082] The method for sulfiding germanium-containing dust in this embodiment includes the following steps:

[0083] (1) Single sulfide leaching: Take a 2L beaker and prepare a 1L solution of sodium sulfide with a concentration of 40g / L using anhydrous sodium sulfide (containing a total of S). 2- 0.53 mol), place the beaker in a water bath at a constant temperature of 50℃, weigh 200g of germanium-containing dust (containing 0.3326g of germanium) and slowly add it, react for 2h, and control the stirring speed at 300rpm. After the reaction is completed, filter to obtain 0.98L of filtrate and 358.4g of filter residue. The residue is then used for the next leaching step.

[0084] (2) Secondary sulfidation leaching: Take a 2L beaker and prepare 0.6L of sodium persulfide solution with a concentration of 20g / L (containing a total of S2). 2- 0.11 mol), put the beaker into a water bath at a constant temperature of 40℃, and add the filter residue obtained in step (1) into the solution for leaching. Control the reaction time to 2h and the stirring speed to 300rpm. After the reaction is completed, filter to obtain 0.95L of filtrate and 264.7g of filter residue. After drying the leaching residue, analyze the germanium content.

[0085] (3) Magnesium sulfate precipitation of germanium: After mixing the leachates obtained in steps (1) and (2), the molar amount of germanium in the mixture is detected. 4.2g of magnesium sulfate is added according to 8 times the molar amount of germanium. The precipitation temperature is controlled at 30℃ and the reaction time is 1h. After the reaction is completed, liquid-solid separation is performed to obtain 6.65g of precipitated germanium residue (containing 0.3169g of germanium). The germanium content of the precipitated residue is determined after the precipitate is dried.

[0086] (4) Oxidation roasting: The precipitated germanium slag dried in step (3) was oxidized and roasted at 850℃ for 3 hours to obtain 1.33g of germanium oxide concentrate (containing 0.3035g of germanium).

[0087] The technical specifications for each process are shown in Table 2:

[0088] Table 2 Technical Specifications for Each Process in Example 1

[0089]

[0090] In this embodiment, the Ge leaching rate is high, reaching 95.28% in the mixed leachate, indicating a good leaching effect. The germanium content in the leachate after germanium precipitation is low, indicating a good germanium precipitation effect. The germanium grade in the obtained concentrate is 22.82%, demonstrating that the method of the present invention has a very good enrichment effect on germanium.

[0091] Example 2

[0092] The germanium-containing dust used in this embodiment has the following composition listed in Table 3.

[0093] Table 3. Composition of germanium-containing dust in Example 2

[0094]

[0095] The method for sulfiding germanium-containing dust in this embodiment includes the following steps:

[0096] (1) Single sulfide leaching: Take a 2L beaker and prepare 0.8L of anhydrous sodium sulfide solution with a sodium sulfide concentration of 90g / L (containing a total of S). 2- 0.92 mol), place the beaker in a water bath at a constant temperature of 55℃, weigh 200g of germanium-containing dust (containing 0.4902g of germanium) and slowly add it, react for 2h, and control the stirring speed at 350rpm. After the reaction is completed, filter to obtain 0.75L of filtrate and 293.7g of filter residue. The residue is then used for the next leaching step.

[0097] (2) Secondary sulfidation leaching: Take a 2L beaker and prepare 0.6L of sodium persulfide solution with a concentration of 30g / L (containing a total of S2). 2- 0.16 mol), put the beaker into a water bath at a constant temperature of 50℃, and add the filter residue obtained in step (1) into the solution for leaching. Control the reaction time to 3h and the stirring speed to 400rpm. After the reaction is completed, filter to obtain 0.97L of filtrate and 248.3g of filter residue. After drying the leaching residue, analyze the germanium content.

[0098] (3) Magnesium sulfate precipitation of germanium: After mixing the leachates obtained in steps (1) and (2), the molar amount of germanium in the mixture is detected. 5.38g of magnesium sulfate is added according to 7 times the molar amount of germanium. The precipitation temperature is controlled at 40℃ and the reaction time is 1h. After the reaction is completed, liquid-solid separation is performed to obtain 8.44g of precipitated germanium residue (containing 0.4641g of germanium). The germanium content of the precipitated residue is determined after the precipitate is dried.

[0099] (4) Oxidation roasting: The precipitated germanium slag dried in step (3) was oxidized and roasted at 900℃ for 3 hours to obtain 1.85g of germanium oxide concentrate (containing 0.4386g of germanium).

[0100] The technical specifications for each process are shown in Table 4:

[0101] Table 4 Technical indexes of each process of Example 2

[0102]

[0103] The Ge leaching rate of this example is high, and the leaching rate in the mixed leaching solution is 94.73%, which indicates that the leaching effect is good, the Ge content in the post-Ge precipitation solution is low, which indicates that the Ge precipitation effect is good, and the Ge grade in the obtained concentrate is 23.71%, which indicates that the method has a good enrichment effect on Ge.

[0104] Example 3

[0105] The Ge-containing flue dust used in this example is listed in Table 5 below.

[0106] Table 5 Composition of Ge-containing flue dust in Example 3

[0107]

[0108] The method for leaching Ge from the Ge-containing flue dust by sulfuration in this example comprises the following steps:

[0109] (1) First sulfuration leaching: take a 2L beaker, prepare a 0.8L solution with a sodium sulfide concentration of 100g / L (containing S1 2- 0.03 mol) using anhydrous sodium sulfide, place the beaker in a water bath with a constant temperature of 50°C, slowly add 200g of Ge-containing flue dust (containing Ge 0.5748g), control the stirring speed at 400rpm, and react for 2.5h. After the reaction is completed, filter to obtain a filtrate of 0.78L and a filter residue of 321.6g. The residue is subjected to the next leaching.

[0110] (2) Second sulfuration leaching: take a 2L beaker, prepare a 0.8L solution with a sodium persulfate concentration of 30g / L (containing S2 2- 0.22 mol) using sodium persulfate, place the beaker in a water bath with a constant temperature of 50°C, and at the same time, add the filter residue obtained in step (1) to the solution for leaching, control the reaction time at 2h, and control the stirring speed at 400rpm. After the reaction is completed, filter to obtain a filtrate of 1.10L and a filter residue of 283.1g. The leaching residue is dried and analyzed for Ge content.

[0111] (3) Magnesium sulfate Ge precipitation: mix the leaching solutions obtained in steps (1) and (2), detect the molar amount of Ge in the mixed solution, add 5.32g of magnesium sulfate according to 6 times the molar amount of Ge, control the precipitation temperature at 40°C, and control the reaction time at 2h. After the reaction is completed, perform liquid-solid separation to obtain a precipitated Ge residue of 9.84g (containing Ge 0.5353g). The post-precipitation liquid is measured for Ge, and the precipitated residue is dried and analyzed for Ge content.

[0112] (4) Oxidation roasting: the dried precipitated germanium residue in step (3) is oxidized and roasted at 950 DEG C for 3h, to obtain germanium concentrate 2.32g (containing germanium 0.5072g).

[0113] The technical indexes of each process are shown in Table 6.

[0114] Table 6 Technical indexes of each process in Example 3

[0115]

[0116] The Ge leaching rate in this example is high, and the leaching rate in the mixed leaching solution is 93.13%, which indicates that the leaching effect is good, the germanium content in the post-germanium precipitation solution is low, which indicates that the germanium precipitation effect is good, and the germanium grade in the obtained concentrate is 21.86%, which indicates that the method has a good enrichment effect on germanium.

[0117] Finally, it should be noted that: the above only for the preferred examples of the present application, and not for limiting the present application, although the present application is described in detail with reference to the foregoing examples, for those skilled in the art, it still can be modified to the technical solutions recorded in the foregoing examples, or equivalent replacement of part of the technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of leaching germanium from a germanium-containing fume by sulfidation, characterized by, The method comprises the following steps: (1) primary sulfide leaching: germanium-containing fume is reacted with a sulfide solution, solid-liquid separation is performed, and a primary leaching solution and a primary leaching residue are obtained; (2) secondary sulfide leaching: the primary leaching residue is reacted with a persulfide solution, solid-liquid separation is performed, and a secondary leaching solution and a secondary leaching residue are obtained; (3) germanium precipitation by magnesium sulfate: germanium is precipitated from the primary leaching solution and / or the secondary leaching solution by adding magnesium sulfate, solid-liquid separation is performed, and a germanium-precipitated solution and a germanium-precipitated residue are obtained; (4) oxidation roasting: the germanium-precipitated residue is roasted, and germanium oxide concentrate is obtained.

2. The method of claim 1, wherein the sulfidizing leaching of germanium from the germanium-containing fume is performed at a temperature of 150 to 250 °C. In step (1), the sulfide in the sulfide solution is sodium sulfide and / or potassium sulfide; in step (2), the persulfide in the persulfide solution is one or a mixture of two or more of sodium persulfate, potassium persulfate and ammonium persulfate.

3. The method of claim 1, wherein the sulfidizing leaching of germanium from the germanium-containing fume is characterized by, In step (1), S in the sulfide solution 2- The ratio of the content of germanium in the germanium-containing fume to the content of sulfur in the sulfide solution is 1-2 mol: 1 g; and the concentration of the sulfide solution is 40-100 g / L.

4. The method of leaching germanium from germanium-containing fume according to any one of claims 1 to 3, wherein In step (1), the reaction temperature is 40-70 ℃, the reaction time is 1-3 h, and stirring is performed during the reaction.

5. The method of claim 1, wherein the sulfidizing leaching of germanium from the germanium-containing fume is characterized by, In step (2), S2- in the persulfide solution 2- The ratio of germanium content in the germanium-containing fume to the persulfide solution is 0.3-0.6 mol:1 g; the concentration of the persulfide solution is 20-50 g / L.

6. The method of leaching germanium from germanium-containing fume dust by sulfidation according to any one of claims 1, 2, 5, characterized in that, In step (2), the reaction temperature is 40-60 ℃, the reaction time is 1-3 h, and stirring is performed during the reaction.

7. The method of leaching germanium from germanium-containing fume dust by sulfidation according to any one of claims 1, 2, 3, 5, characterized in that, In step (3), the amount of magnesium sulfate used is 5-8 times the germanium content in the solution in terms of molar amount.

8. The method of leaching germanium from germanium-containing fume dust by sulfidation according to any one of claims 1, 2, 3, 5, characterized in that, In step (3), the temperature during the germanium precipitation is 30-50 ℃, and the reaction time is 1-2 h.

9. The method of leaching germanium from germanium-containing fume dust by sulfidation according to any one of claims 1, 2, 3, 5, characterized in that, In step (4), the roasting temperature is 800-1000 ℃, and the roasting time is 3-5 h.

10. The method of leaching germanium from germanium-containing fume dust by sulfidation according to any one of claims 1, 2, 3, 5, characterized in that, The germanium-precipitated solution obtained in step (3) is supplemented with sulfide and then returned to step (1) as the sulfide solution.

Images