A method for extracting germanium-humic acid coexisting substance from germanium-containing lignite

Abstract

The present application relates to a kind of methods for extracting germanium-humic acid coexistence from germanium-containing lignite.Belongs to germanium extraction technical field, the method includes extracting germanium-humic acid coexistence from germanium-containing lignite by leaching treatment with ammonia as leaching agent in oxygen atmosphere.The method for extracting germanium-humic acid coexistence from germanium-containing lignite of the present application improves the leaching rate of germanium, has high coal yield, is green and environmentally friendly, and the obtained residual coal can be modified and effectively recovered.

Description

TECHNICAL FIELD

[0001] The present application relates to germanium extraction technology, and in particular to a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite. BACKGROUND

[0002] Germanium tends to be complexed with organic matter in coal and is mostly uniformly enriched in the agglomerate humic substance of lignite. Due to the development of side chains and functional groups of lignite molecules, lignite has more organic complexation sites, so almost all germanium-containing coals with industrial value are lignite.

[0003] Currently, germanium-containing lignite is mainly enriched into germanium concentrate through pyrogenic enrichment, and then extracted by chlorination distillation. Germanium extraction from coal dust after combustion of germanium-containing lignite through chlorination distillation has been industrialized for more than 50 years, and the technology is mature and the equipment is low in complexity. The germanium recovery rate is generally 40% to 60%. However, as the first step in the extraction process, the leaching step needs to use high-concentration hydrochloric acid to achieve selective dissolution and strengthen the dissolution process. There are technical and cost problems such as strong system acidity, large amount of waste acid, and difficulty in harmless disposal of residues. In addition, part of the heat energy generated during combustion needs to be sacrificed to take into account the grade of germanium in the coal dust. SUMMARY

[0004] In view of the above, the present application aims to provide a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite, which solves one of the problems of low germanium recovery rate and ineffective utilization of humic acid in the existing lignite germanium extraction process.

[0005] In a first aspect, an embodiment of the present application provides a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite, comprising extracting germanium-humic acid coexisting substances from germanium-containing lignite by leaching treatment under an oxygen atmosphere using ammonia as a leaching agent.

[0006] According to an embodiment of the present application, the method comprises the following steps:

[0007] S1: providing a first mixture comprising germanium-containing lignite and ammonia;

[0008] S2: leaching the first mixture under an oxygen atmosphere to obtain a second mixture; and

[0009] S3: performing solid-liquid separation on the second mixture, and then freeze-drying the liquid phase to obtain germanium-humic acid coexisting substances.

[0010] According to an embodiment of the present application, in the first mixture, the mass of the ammonia is 10 to 20 times the mass of the germanium-containing lignite.

[0011] According to an embodiment of the present application, the mass percentage concentration of the ammonia is 10% to 20%.

[0012] According to an embodiment of the present application, the temperature of the leaching treatment is 25-85 DEG C.

[0013] According to an embodiment of the present application, the time of the leaching treatment is 3-4 h.

[0014] According to an embodiment of the present application, the leaching treatment is carried out under an oxygen atmosphere, and the pressure of the leaching treatment is 0.5-1.2 MPa.

[0015] According to an embodiment of the present application, the step S3 comprises:

[0016] The second mixture is subjected to solid-liquid separation to obtain residual coal and a germanium-humic acid coexisting solution, and the solution is subjected to freeze drying to obtain germanium-humic acid coexisting matter.

[0017] According to an embodiment of the present application, the solid-liquid separation is carried out by suction filtration or centrifugation.

[0018] According to an embodiment of the present application, the freeze drying is carried out for 23-25 h.

[0019] According to an embodiment of the present application, the residual coal is used to prepare carbon materials.

[0020] According to an embodiment of the present application, further comprising: desorbing and deeply enriching germanium in the germanium-humic acid coexisting matter by sulfoxide chloride leaching.

[0021] According to an embodiment of the present application, the process steps of desorbing and deeply enriching germanium comprise:

[0022] S4: uniformly mixing the germanium-humic acid coexisting matter with sulfoxide chloride to obtain a third mixture;

[0023] S5: placing the third mixture in a single-necked flask and starting leaching treatment by stirring; in the process, germanium is leached into the solution;

[0024] S6: after the leaching is completed, the mixture in the single-necked flask is taken out, and solid-liquid separation is repeatedly carried out by suction filtration; the obtained solid is washed with deionized water for multiple times, and dried to obtain humic acid from which germanium is unloaded; the sulfoxide chloride leaching solution and the washing solution are respectively evaporated and dried to obtain germanium-rich solid.

[0025] According to an embodiment of the present application, in S4, the mass of the sulfoxide chloride is 1-4 times the mass of the germanium-humic acid coexisting matter.

[0026] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0027] The method for extracting germanium-humic acid coexisting matters from germanium-containing lignite of the present application extracts germanium-humic acid coexisting matters from germanium-containing lignite by leaching treatment under oxygen atmosphere with ammonia water as leaching agent, and the germanium leaching rate can reach more than 60%; the organic matter and the dispersed metal germanium can be cooperatively leached out. Oxygen participates in the oxidation reaction of coal, enriches the amount of humic acid, and the weak oxidation can remove part of the phenolic hydroxyl groups in coal, and more carboxyl groups are generated by ring opening of the coal structure, the germanium complexed by the phenolic hydroxyl groups is separated from the original structure and fixed by the carboxyl groups; the reaction of ammonia molecules with the carboxyl groups causes the coal to be solubilized and converted, and the humic acid is changed into water-soluble humic acid salt form, and the germanium also enters the solution; the oxidation and ammoniation can leach out a large amount of humic acid in lignite, and the process modifies the structure of lignite, so that the nitrogen content in the leached humic acid is significantly improved, and the high nitrogen content makes it can be used as long-acting slow-release nitrogen fertilizer or super capacitor precursor raw material.

[0028] The method for extracting germanium-humic acid coexisting matters from germanium-containing lignite of the present application can achieve effective recovery with the yield of the obtained coal being more than 90% (for example, more than 95%) after leaching operation, and the residual coal can be used as modified nitrogen-rich organic fertilizer; the germanium-humic acid coexisting matters change greatly compared with the original coal, mainly in the significant improvement of nitrogen content and the significant presence of nitrogen-containing functional groups; after unloading germanium, the germanium-humic acid coexisting matters can be used as a nitrogen-doped raw material for modified nitrogen-rich organic fertilizer or super capacitor electrode material.

[0029] The method for extracting germanium-humic acid coexisting matters from germanium-containing lignite of the present application has simple process flow, high resource comprehensive utilization rate, and small environmental pollution, realizes high-value and clean utilization of lignite, saves cost, has remarkable economic benefit, and the main micro high-pressure reaction kettle equipment used is mature and easy to industrialize.

[0030] The method for extracting germanium-humic acid coexisting matters from germanium-containing lignite of the present application can efficiently and mildly leach germanium and humic acid from germanium-containing lignite, and realize comprehensive utilization of lignite organic matter.

[0031] In the present application, the above technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purposes and other advantages of the present application can be realized and obtained through the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are only for the purpose of illustrating specific embodiments and are not considered as limitations of the present application. Among them:

[0033] Figure 1A process flow chart for extracting germanium-humic acid coexisting substances from germanium-containing lignite according to an embodiment of the present application;

[0034] Figure 2 FIG. 4 is a comparison of infrared spectrograms of the residual coal and humic acid obtained in Example 2 of the present application and the raw germanium-containing lignite. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present application are specifically described below, wherein the accompanying drawings form a part of the present application and are used together with the embodiments of the present application to explain the principles of the present application, but not to limit the scope of the present application.

[0036] The inventors have found in long-term and in-depth research that germanium exists in the form of Ge-O coordination structure of tetravalent oxidation state and deformed octahedron in coal due to its oxygen affinity, and the phenolic hydroxyl structure is the most likely functional group related to germanium enrichment, so the destruction or modification of the phenolic hydroxyl group is the key to the germanium in coal to separate from the original structure.

[0037] An embodiment of the present application provides a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite, which comprises extracting germanium-humic acid coexisting substances from germanium-containing lignite by leaching treatment under an oxygen atmosphere with ammonia water as a leaching agent.

[0038] The method for extracting germanium-humic acid coexisting substances from germanium-containing lignite according to an embodiment of the present application comprises the following steps:

[0039] S1: providing a first mixture comprising germanium-containing lignite and ammonia water;

[0040] S2: performing leaching treatment on the first mixture under an oxygen atmosphere to obtain a second mixture; and

[0041] S3: performing solid-liquid separation on the second mixture, and then performing freeze-drying on the liquid phase to obtain germanium-humic acid coexisting substances.

[0042] In an embodiment, the germanium-containing lignite has a germanium content of 20 μg / g or more.

[0043] In an embodiment, in S1, the finely ground germanium-containing lignite and the leaching agent ammonia water can be uniformly mixed in a certain proportion. Considering that too much ammonia water will cause the cost to rise, and too little ammonia water will result in low contact efficiency with the coal. Therefore, the mass of ammonia water can be 10-20 times the mass of the germanium-containing lignite, for example, 12 times, 14 times, 15 times, 16 times, or 18 times.

[0044] In an embodiment, in S1, the particle size of the finely ground germanium-containing lignite is finer than 200 mesh.

[0045] In an embodiment, in S1, considering that too high mass percentage concentration of ammonia water causes more inorganic impurities to be dissolved, and too low mass percentage concentration is not enough to make the reaction complete, the mass percentage concentration of raw ammonia water can be controlled to be 10% to 20%, for example, 12%, 14%, 15%, 16%, 18%.

[0046] In an embodiment, in S2, oxygen participates in the oxidation reaction of coal, enriches the amount of humic acid, and weak oxidation can remove part of the phenolic hydroxyl groups in coal, and more carboxyl groups are produced by ring-opening of the coal structure, the germanium complexed by the phenolic hydroxyl groups is separated from the original structure and fixed by the carboxyl groups; the reaction of ammonia molecules with carboxyl groups causes the coal to be solubilized and converted, and the humic acid is changed into water-soluble humic acid salt form, and germanium also enters the solution; considering that too high temperature of leaching treatment can cause too strong oxidation, so that germanium is not easy to separate, and too low temperature cannot achieve efficient weak oxidation. Therefore, the temperature of leaching treatment can be controlled to be 25 to 85°C, for example, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C.

[0047] In an embodiment, in S2, considering that too long leaching time increases time cost, and too short leaching time cannot make the weak oxidation-ammoniation process completely, the leaching time can be controlled to be 3 to 4 hours, for example, 3.5 hours.

[0048] In an embodiment, oxygen is used as the environmental atmosphere of leaching treatment, considering that too high leaching pressure increases the load of equipment, and too low leaching pressure cannot effectively achieve the effect of weak oxidation. Therefore, the pressure of leaching treatment can be controlled to be 0.5 to 1.2 MPa, for example, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa. Oxidation and ammoniation can dissolve a large amount of humic acid in lignite, and the process modifies the structure of lignite, so that the nitrogen content of the dissolved humic acid is significantly improved. The high nitrogen content makes it can be used as long-acting slow-release nitrogen fertilizer or supercapacitor precursor raw material.

[0049] In an embodiment, in S2, considering that too high stirring rate of leaching treatment increases energy consumption, and too low stirring rate cannot make the solid-liquid-gas three phases contact efficiently. Therefore, the stirring rate of the first mixture in the leaching treatment process can be controlled to be 700 to 800 r / min, for example, 710 r / min, 720 r / min, 740 r / min, 750 r / min, 760 r / min, 780 r / min.

[0050] In an embodiment, in S2, a micro high-pressure reaction kettle can be used as the container for leaching treatment. Further, the first mixture can be placed in the micro high-pressure reaction kettle, oxygen with a certain pressure is introduced as the environmental atmosphere, heating and stirring are started, the temperature is raised to the set temperature, and the leaching treatment is started.

[0051] In an embodiment, after the temperature in the micro high-pressure reactor is reduced to 20-28°C (for example, 22°C, 24°C, 25°C, or 26°C), the second mixture obtained by the leaching treatment is taken out of the reactor.

[0052] In an embodiment, in S3, the second mixture can be subjected to solid-liquid separation by filtration or centrifugation to obtain solids and liquids. Further, the solid-liquid separation operation can be repeated 3-5 times, for example, 4 times.

[0053] In an embodiment, in S3, the second mixture is treated to obtain residual coal and germanium-humic acid coexisting substances. The residual coal is rich in nitrogen elements and can be used as a modified nitrogen-rich organic fertilizer. The germanium-humic acid coexisting substances are also rich in nitrogen elements and can be used as a modified nitrogen-rich organic fertilizer or a nitrogen-doped raw material for supercapacitor electrode materials after germanium is precipitated.

[0054] In an embodiment, in S3, the obtained solids are washed with water and dried to obtain nitrogen-rich residual coal. The washing can be performed 3-6 times, for example, 4 times or 5 times. The solution obtained after the washing of the solids and the separation of the liquids is a germanium-humic acid coexisting substance solution. The germanium-humic acid coexisting substances include modified humic acid salts. The washed solution can be mixed with the liquid obtained by the solid-liquid separation. The germanium-humic acid coexisting substances include, but are not limited to, modified humic acid salts. Subsequently, the germanium-humic acid coexisting substances can be subjected to the desorption and deep enrichment of germanium by the thionyl chloride leaching method.

[0055] In an embodiment, the process steps for the desorption and deep enrichment of germanium from the germanium-humic acid coexisting substances by the thionyl chloride leaching method include:

[0056] S4: uniformly mixing the germanium-humic acid coexisting substances with thionyl chloride to obtain a third mixture;

[0057] S5: placing the third mixture in a single-neck flask and starting the stirring for leaching treatment. In this process, the germanium is leached into the solution.

[0058] S6: taking out the mixture in the single-neck flask after the leaching is completed, and repeatedly performing solid-liquid separation by filtration. The obtained solids are washed with deionized water for multiple times, and dried to obtain humic acid from which the germanium is unloaded. The thionyl chloride leaching solution and the washing solution are evaporated and dried to obtain germanium-rich solids.

[0059] In an embodiment, in S4, considering that too much thionyl chloride increases the cost, and too little thionyl chloride has a low contact efficiency with the germanium-humic acid coexisting substances. Therefore, the mass of the thionyl chloride can be 1-4 times, for example, 2 times, 3 times, or 4 times, the mass of the germanium-humic acid coexisting substances.

[0060] In an embodiment, in S5, considering that too high temperature of the leaching treatment can cause decomposition of thionyl chloride, and too low temperature cannot achieve efficient leaching, the temperature of the leaching treatment is controlled to be 1-5°C, for example, 2°C, 3°C, 4°C.

[0061] In an embodiment, in S5, considering that too long time of the leaching treatment increases time cost, and too short time cannot leach germanium completely, the time of the leaching treatment is controlled to be 5-25 min, for example, 10 min, 15 min, 20 min.

[0062] In an embodiment, in S5, considering that too high stirring rate of the leaching treatment increases energy consumption, and too low stirring rate cannot make solid and liquid contact sufficiently and efficiently, the stirring rate in the leaching treatment is controlled to be 30-80 r / min, for example, 40 r / min, 50 r / min, 60 r / min, 70 r / min.

[0063] The method for extracting germanium-humic acid coexisting substances from germanium-containing lignite in an embodiment of the present application is a technology for germanium extraction by ammonia treatment, and has high germanium leaching rate and can achieve simultaneous dissolution of organic matter and dispersed metal germanium. Oxygen participates in the oxidation reaction of coal, enriches the amount of humic acid, and the weak oxidation effect can remove part of phenolic hydroxyl groups in the coal, and more carboxyl groups are generated by ring opening of the coal structure. The germanium complexed by the phenolic hydroxyl groups is separated from the original structure and fixed by the carboxyl groups. The reaction of ammonia molecules with the carboxyl groups causes solubilization and conversion of the coal, and the humic acid is changed into water-soluble humic acid salt form, and the germanium also enters the solution. The oxidation and ammonia treatment can dissolve a large amount of humic acid in the lignite, and the structure of the lignite is modified in the process, so that the nitrogen content in the dissolved humic acid is significantly increased. The high nitrogen content makes the humic acid suitable for use as long-acting slow-release nitrogen fertilizer or supercapacitor precursor raw material.

[0064] The existing chlorination distillation technology uses coal dust generated after coal combustion as the germanium extraction raw material, has low leaching rate, generates a large amount of waste acid, and the germanium recovery rate is generally 40%-60%. In addition, the combustion process pollutes the environment. In an embodiment of the present application, the method for extracting germanium-humic acid coexisting substances from germanium-containing lignite uses ammonia water as a leaching agent for ammonia leaching in an oxygen atmosphere, and the germanium leaching rate can reach more than 61% (for example, 61.39%-70.11%). The method can achieve simultaneous dissolution of organic matter and dispersed metal germanium. Compared with the traditional chlorination leaching, the reagent has weak acid and alkali degree, the conditions are relatively mild, the germanium leaching rate is effectively improved, and a large amount of waste acid is not generated, thereby reducing the harm of the leaching process to the environment. The residual coal can be used as a nitrogen-rich organic fertilizer, thereby reducing resource waste and environmental pollution caused by the combustion process.

[0065] The method for extracting germanium-humic acid coexisting substances from germanium-containing lignite according to an embodiment of the present application has a coal yield of more than 90% (for example, more than 95%) after leaching operation, can achieve effective recovery, and can utilize residual coal as modified nitrogen-rich organic fertilizer. The oxidation and ammonification process modifies the structure of lignite, significantly increases the nitrogen content in dissolved humic acid, and the germanium-humic acid coexisting substances can be used as long-acting slow-release nitrogen fertilizer or supercapacitor precursor raw material after germanium is unloaded.

[0066] The method for extracting germanium-humic acid coexisting substances from germanium-containing lignite according to an embodiment of the present application has a simple process flow, high resource comprehensive utilization rate, and small environmental pollution, realizes high-value and clean utilization of lignite, saves cost, has remarkable economic benefits, and uses mature main micro high-pressure reaction kettle equipment, which is easy to industrialize.

[0067] The method for extracting germanium-humic acid coexisting substances from germanium-containing lignite according to an embodiment of the present application can efficiently and mildly leach germanium and humic acid from germanium-containing lignite and realize comprehensive utilization of lignite organic matter.

[0068] Hereinafter, the method for extracting germanium-humic acid coexisting substances from germanium-containing lignite according to an embodiment of the present application will be further described in combination with the accompanying drawings and specific embodiments. Among them,

[0069] The calculation formula of the germanium leaching rate is: (1)

[0070] m 腐植酸 m represents the mass of humic acid, a 腐植酸 m represents the content of germanium in the germanium-humic acid coexisting substances, m 原煤 m represents the mass of raw coal, a 残煤 m represents the content of germanium in the residual coal. The raw coal refers to the germanium-containing lignite used as raw material.

[0071] Example 1

[0072] The embodiment provides a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite, which comprises the following steps:

[0073] S1: 5 g of germanium-containing lignite (germanium content 120 g / t) sieved through a 200-mesh sieve is uniformly mixed with ammonia water with a concentration of 10% to obtain a first mixture; wherein the addition amount of ammonia water is 10 times the weight of germanium-containing lignite.

[0074] S2: the first mixture is placed in a micro high-pressure reaction kettle, oxygen is introduced as an environmental atmosphere, the pressure of oxygen is 0.5 MPa; heating and stirring are started, the stirring rate is 710 r / min, the temperature is raised to 40 DEG C for leaching treatment, and the leaching time is 3 h; in this process, the germanium-humic acid coexisting substances are leached into the solution.

[0075] S3: After the end of leaching, the contents in the kettle were taken out to obtain a second mixture, and solid-liquid separation was repeated three times by suction filtration; the separated solids were washed with deionized water five times, and after drying, nitrogen-rich residual coal was obtained, which was weighed; the separated solution was a nitrogen-rich germanium-humic acid coexisting substance solution, and the above washing solution was added to the separated solution; the total obtained solution was freeze-dried for 24 h to obtain germanium-humic acid coexisting substances with a mass of 1.932 g, and after digestion, the germanium content was 201 g / t;

[0076] S4: The germanium-humic acid coexisting substances were uniformly mixed with thionyl chloride to obtain a third mixture, wherein the addition amount of thionyl chloride was 3 times that of the germanium-humic acid coexisting substances.

[0077] S5: The third mixture was placed in a single-necked flask, and leaching treatment was performed with stirring turned on, the leaching treatment temperature was 3°C, the stirring rate was 80 r / min, and the leaching time was 20 min; in this process, germanium was leached into the solution.

[0078] S6: After the end of leaching, the mixture in the single-necked flask was taken out, and solid-liquid separation was repeated three times by suction filtration; the separated solids were washed with deionized water five times, and after drying, germanium-unloaded humic acid was obtained, which was weighed; the thionyl chloride leaching solution and the washing solution were evaporated and dried to obtain germanium-rich solids, respectively.

[0079] The germanium content in the germanium-humic acid coexisting substances after digestion was determined by ICP-OES, and the germanium leaching rate was calculated according to formula (1) to be 64.58%; after leaching of the germanium-humic acid coexisting substances by thionyl chloride, the germanium therein was separated, and the overall germanium recovery rate was 64.22%; the sum of the mass of the nitrogen-rich residual coal and the germanium-unloaded humic acid was the mass of the recovered coal, and the coal recovery rate was 99.32%.

[0080] Example 2

[0081] The present embodiment provides a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite, comprising the following steps:

[0082] S1: 5 g of germanium-containing lignite (germanium content 120 g / t) sieved through a 200-mesh sieve was uniformly mixed with ammonia water with a concentration of 10% to obtain a first mixture; wherein the addition amount of ammonia water was 11 times the weight of germanium-containing lignite.

[0083] S2: The first mixture was placed in a micro high-pressure reaction kettle, and oxygen was introduced as the environmental atmosphere, with an oxygen pressure of 0.6 MPa; heating and stirring were turned on, the stirring rate was 730 r / min, the temperature was raised to 80°C for leaching treatment, and the leaching time was 3 h; in this process, germanium-humic acid coexisting substances were leached into the solution.

[0084] S3: After the leaching is completed, the substance in the kettle is taken out to obtain a second mixture, and solid-liquid separation is repeatedly performed three times by suction filtration; the separated solid is washed with deionized water five times, and after drying, a nitrogen-rich residual coal is obtained, and the weight is measured; the separated solution is a nitrogen-rich germanium-humic acid coexisting substance solution, and the above washing solution is added to the separated solution. The total obtained solution is freeze-dried for 24 h to obtain germanium-humic acid coexisting substances with a mass of 1.657 g, and after digestion, the germanium content is 254 g / t;

[0085] S4: The germanium-humic acid coexisting substances are uniformly mixed with thionyl chloride to obtain a third mixture, wherein the addition amount of thionyl chloride is 4 times that of the germanium-humic acid coexisting substances.

[0086] S5: The third mixture is placed in a single-necked flask, and stirring is started for leaching treatment, the leaching treatment temperature is 2℃, the stirring rate is 50 r / min, and the leaching time is 5 min, and in this process, germanium is leached into the solution.

[0087] S6: After the leaching is completed, the mixture in the single-necked flask is taken out, and solid-liquid separation is repeatedly performed three times by suction filtration; the separated solid is washed with deionized water five times, and after drying, a germanium-unloaded humic acid is obtained, and the weight is measured; the thionyl chloride leaching solution and the washing solution are evaporated and dried to obtain a germanium-rich solid.

[0088] The germanium content in the germanium-humic acid coexisting substances after digestion is determined by ICP-OES, and the germanium leaching rate is calculated according to formula (1) to be 70.25%; the germanium in the germanium-humic acid coexisting substances after thionyl chloride leaching is separated, and the overall germanium recovery rate is 70.11%; the sum of the mass of the nitrogen-rich residual coal and the germanium-unloaded humic acid is the mass of the recovered coal, and the coal recovery rate is 98.46%.

[0089] Example 3

[0090] The embodiment provides a method for extracting germanium-humic acid coexisting substances from germanium-containing lignite, comprising the following steps:

[0091] S1: 5 g of germanium-containing lignite (germanium content 120 g / t) sieved through a 200-mesh sieve is uniformly mixed with ammonia water with a concentration of 10% to obtain a first mixture; wherein the addition amount of ammonia water is 13 times the weight of the germanium-containing lignite.

[0092] S2: The first mixture is placed in a micro high-pressure reaction kettle, oxygen is introduced as the environmental atmosphere, the oxygen pressure is 0.8 MPa; heating and stirring are started, the stirring rate is 750 r / min, the temperature is raised to 85℃ for leaching treatment, and the leaching time is 3 h; in this process, the germanium-humic acid coexisting substances are leached into the solution.

[0093] S3: After the end of leaching, the material in the kettle is taken out to obtain a second mixture, and solid-liquid separation is repeated three times by suction filtration; the separated solid is washed with deionized water five times, and after drying, a nitrogen-rich residual coal is obtained, which is weighed; the separated solution is a nitrogen-rich germanium-humic acid coexisting substance solution, and the washing solution is added to the separated solution. The total obtained solution is freeze-dried for 24 h to obtain germanium-humic acid coexisting substances with a mass of 1.732 g, and after digestion, the germanium content is 214 g / t;

[0094] S4: The germanium-humic acid coexisting substances are uniformly mixed with thionyl chloride to obtain a third mixture, wherein the addition amount of thionyl chloride is 2 times that of the germanium-humic acid coexisting substances;

[0095] S5: The third mixture is placed in a single-necked flask, and leaching treatment is performed by opening the stirring, the temperature of the leaching treatment is 1 ℃, the stirring rate of the leaching treatment is 30 r / min, and the leaching time is 10 min, in the process, germanium is leached into the solution;

[0096] S6: After the end of leaching, the mixture in the single-necked flask is taken out, and solid-liquid separation is repeated three times by suction filtration; the separated solid is washed with deionized water five times, and after drying, a germanium-unloaded humic acid is obtained, which is weighed; the thionyl chloride leaching solution and the washing solution are evaporated and dried to obtain a germanium-rich solid.

[0097] The germanium content in the germanium-humic acid coexisting substances after digestion is determined by ICP-OES, and the germanium leaching rate is calculated according to formula (1) to be 61.68%; after the germanium-humic acid coexisting substances are leached by thionyl chloride, the germanium therein is separated, and the germanium recovery rate of the whole process is 61.39%; the sum of the mass of the nitrogen-rich residual coal and the germanium-unloaded humic acid is the mass of the recovered coal, and the coal recovery rate is 95.38%.

[0098] Table 1 below is the nitrogen content data of the germanium-humic acid coexisting substances extracted from germanium-containing lignite at different temperatures according to an embodiment of the present application. It can be seen that the germanium-humic acid coexisting substances obtained by the present application are rich in nitrogen element (N content is more than 8%, for example, 8.99%~20.73%), and can be used as a modified nitrogen-rich organic fertilizer or a nitrogen-doped raw material for supercapacitor electrode materials after germanium is precipitated.

[0099] Table 1 Nitrogen content data of germanium-humic acid coexisting substances

[0100]

[0101] Figure 2Comparing the infrared spectrum of the residual coal and humic acid obtained in Example 2 of the present application with the raw material germanium-containing lignite, it can be seen that the present application realizes the modification of germanium-containing lignite by leaching the germanium-containing lignite with ammonia water as a leaching agent in an oxygen atmosphere. The germanium-humic acid coexistence product changes greatly compared with the raw coal, mainly reflected in the significant increase in nitrogen content and the significant presence of nitrogen-containing functional groups.

[0102] The inventors conducted a large number of studies during the research process, and some of the less effective schemes are listed as follows:

[0103] Comparative Example 1

[0104] The present comparative example provides a method for extracting germanium-humic acid coexistence product from germanium-containing lignite, comprising the following steps:

[0105] S1: 5 g of germanium-containing lignite (germanium content 120 g / t) sieved through a 200 mesh sieve was uniformly mixed with ammonia water with a concentration of 5% to obtain a first mixture; wherein the amount of ammonia water added was 10 times the weight of the germanium-containing lignite.

[0106] S2: The first mixture was placed in a micro high-pressure reaction kettle, and oxygen was introduced as the environmental atmosphere, with an oxygen pressure of 0.2 MPa; heating and stirring were turned on, and the temperature was raised to 110°C for leaching treatment, with a leaching time of 1 h; during this process, the germanium-humic acid coexistence product was leached into the solution.

[0107] S3: After the leaching was completed, the kettle contents were removed to obtain a second mixture, and solid-liquid separation was repeated three times by suction filtration; the separated solids were washed with deionized water five times, and after drying, nitrogen-rich residual coal was obtained, which was weighed; the separated solution was a nitrogen-rich germanium-humic acid coexistence product solution, and the washing solution was combined with the separated solution. The total solution was freeze-dried for 24 h to obtain germanium-humic acid coexistence product with a mass of 1.322 g, and after digestion, the germanium content was 234 g / t;

[0108] S4: The germanium-humic acid coexistence product was uniformly mixed with thionyl chloride to obtain a third mixture, wherein the amount of thionyl chloride added was 6 times that of the germanium-humic acid coexistence product;

[0109] S5: The third mixture was placed in a single-necked flask, and stirring was turned on for leaching treatment, with a leaching treatment temperature of 30°C, a stirring rate of 150 r / min, and a leaching time of 1 h; during this process, germanium was leached into the solution;

[0110] S6: After the leaching was completed, the mixture in the single-necked flask was removed, and solid-liquid separation was repeated three times by suction filtration; the separated solids were washed with deionized water five times, and after drying, germanium-unloaded humic acid was obtained, which was weighed; the thionyl chloride leaching solution and the washing solution were evaporated and dried to obtain germanium-rich solids, respectively.

[0111] The content of germanium in the germanium-humic acid coexistence substance after digestion was determined by ICP-OES, and the germanium leaching rate was calculated to be 51.45% according to formula (1); the germanium in the germanium-humic acid coexistence substance was separated after thionyl chloride leaching, and the overall germanium recovery rate was 50.43%; the sum of the mass of the nitrogen-rich residual coal and the humic acid unloaded with germanium was the mass of the recovered coal, and the coal recovery rate was 86.72%.

[0112] Comparative Example 2

[0113] The present comparative example provides a method for extracting germanium-humic acid coexistence substance from germanium-containing lignite, comprising the following steps:

[0114] S1: 5 g of germanium-containing lignite (germanium content 120 g / t) sieved through a 200-mesh sieve was uniformly mixed with ammonia water with a concentration of 25% to obtain a first mixture; wherein the amount of ammonia water added was 10 times the weight of the germanium-containing lignite.

[0115] S2: The first mixture was placed in a micro high-pressure reaction kettle, and oxygen was introduced as the environmental atmosphere, with an oxygen pressure of 1.3 MPa; heating and stirring were started, and the temperature was raised to 150°C for leaching treatment, and the leaching time was 5 h; in this process, the germanium-humic acid coexistence substance leached into the solution.

[0116] S3: After the leaching was completed, the kettle contents were removed to obtain a second mixture, and solid-liquid separation was repeated three times by suction filtration; the separated solid was washed with deionized water five times, and after drying, a nitrogen-rich residual coal was obtained and weighed; the separated solution was a nitrogen-rich germanium-humic acid coexistence solution, and the washing solution was added to the separated solution. The total obtained solution was freeze-dried for 24 h to obtain germanium-humic acid coexistence substance with a mass of 1.217 g, and after digestion, the germanium content was 239 g / t;

[0117] S4: The germanium-humic acid coexistence substance was uniformly mixed with thionyl chloride to obtain a third mixture, wherein the amount of thionyl chloride added was 10 times that of the germanium-humic acid coexistence substance;

[0118] S5: The third mixture was placed in a single-necked flask, and stirring was started for leaching treatment, with a leaching treatment temperature of 80°C, a stirring rate of 300 r / min, and a leaching time of 6 h; in this process, the germanium leached into the solution;

[0119] S6: After the leaching was completed, the mixture in the single-necked flask was removed, and solid-liquid separation was repeated three times by suction filtration; the separated solid was washed with deionized water five times, and after drying, a humic acid unloaded with germanium was obtained and weighed; the thionyl chloride leachate and the washing solution were evaporated and dried to obtain a germanium-rich solid.

[0120] The germanium-humic acid coexisting substance is digested, and the content of germanium in the germanium-humic acid coexisting substance is determined by ICP-OES, and the germanium leaching rate is calculated as 48.39% according to formula (1); the germanium in the germanium-humic acid coexisting substance is separated after being leached by thionyl chloride, and the germanium recovery rate of the whole process is 47.92%. The sum of the mass of the nitrogen-rich residual coal and the humic acid unloaded with germanium is the mass of the recovered coal, and the coal recovery rate is 82.11%.

[0121] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for extracting germanium-humic acid coexistence from germanium-containing lignite, characterized in that, The method includes extracting germanium-humic acid coexistence from germanium-containing lignite by leaching with ammonia water as the leaching agent under an oxygen atmosphere; including the following steps: S1: Provide a first mixture comprising germanium-containing lignite and ammonia water; S2: The first mixture is leached under an oxygen atmosphere to obtain a second mixture; and S3: The second mixture is subjected to solid-liquid separation to obtain residual coal and germanium-humic acid coexistence solution. The solution is freeze-dried to obtain germanium-humic acid coexistence. S4: The germanium-humic acid coexistence is uniformly mixed with thionyl chloride to obtain a third mixture; S5: Place the third mixture in a single-necked flask, turn on the stirrer to carry out the leaching process, during which germanium leaches into the solution; S6: After leaching, the mixture in the single-necked flask is removed and solid-liquid separation is repeated multiple times by vacuum filtration; the separated solid is washed multiple times with deionized water and dried to obtain germanium-containing humic acid; the thionyl chloride leachate and washing solution are evaporated and dried to obtain germanium-rich solid. In step S4, the mass of thionyl chloride is controlled to be 1 to 4 times the mass of the germanium-humic acid coexisting substance. In step S5, the leaching temperature is controlled to be 1–5°C; the leaching time is controlled to be 5–25 min; and the stirring rate during the leaching process is controlled to be 30–80 r / min. After leaching, the yield of coal is over 95%.

2. The method according to claim 1, characterized in that, In the first mixture, the mass of the ammonia water is 10 to 20 times the mass of the germanium-containing lignite.

3. The method according to claim 1, characterized in that, In the first mixture, the mass percentage concentration of the ammonia water is 10% to 20%.

4. The method according to claim 1, characterized in that, In S2, the leaching temperature is 25–85°C.

5. The method according to claim 1, characterized in that, In step S2, the leaching pressure is 0.5–1.2 MPa.

6. The method according to claim 1, characterized in that, In step S4, the mass of thionyl chloride is controlled to be 2 to 4 times the mass of the germanium-humic acid coexisting substance.

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