Method for dissolving beryllium from beryllium-containing sludge

Abstract

The application provides a method for dissolving beryllium in beryllium-containing sludge, which comprises the following steps: mixing a first control agent with beryllium-containing sludge, and then performing first constant-temperature stirring treatment to obtain a solid-liquid mixture, wherein the first control agent is a solution containing carbonate ions; then, adding a second control agent into the solid-liquid mixture drop by drop, and performing second constant-temperature stirring treatment to obtain a beryllium-containing filtrate and a beryllium-removed filter residue, wherein the second control agent is an acid solution; and the treatment temperature of the first constant-temperature stirring treatment and the second constant-temperature stirring treatment is 25-75 DEG C. Compared with the prior art, the method has the advantages of mild treatment condition, no special pH condition, and high-efficiency dissolution of beryllium in beryllium-containing sludge at a low temperature of 25-75 DEG C. The method has strong application and is suitable for industrialization due to the characteristics of low cost, low process equipment requirement and simple operation.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment and comprehensive utilization, and in particular to a method for leaching beryllium from beryllium-containing sludge. Background Technology

[0002] Currently, domestic manufacturers of beryllium oxide mainly employ a modified "Degusa" sulfuric acid process. For details, see *China Beryllium Industry*, pp. 102-107. The beryllium-containing wastewater generated during the "Degusa" process for beryllium hydroxide production originates from the large amount of precipitated waste liquid remaining after beryllium hydroxide precipitation, the washing liquid from leaching residues such as leaching residue, aluminum ammonium alum, and neutralized iron slag, the rinsing water from dust removal and purification devices, equipment washing water, and washing water from work clothes and operating floors. This beryllium-containing wastewater contains soluble beryllium sulfate and requires treatment before discharge. Currently, the main treatment method for beryllium-containing wastewater is lime slurry neutralization, where most beryllium ions precipitate as beryllium hydroxide from the solution, forming beryllium-containing sludge after flocculation and precipitation.

[0003] After drying and dehydration, beryllium-containing sludge contains 0.3-0.4 wt% beryllium. Beryllium and its compounds are highly toxic substances. Beryllium-containing sludge has been listed under item HW20 (wastewater treatment sludge) in the National Hazardous Waste List. Therefore, it is urgent to treat beryllium-containing sludge.

[0004] In existing technologies, the method of selectively extracting beryllium from beryllium-containing sludge using hydrothermal mineral phase regulation can leach more than 84% of the beryllium in the beryllium-containing sludge. However, it requires hydrothermal treatment under acidic conditions, and the hydrothermal treatment temperature needs to be above 150°C. This requires a large external energy supply, has high costs, and places high demands on process equipment, making it unsuitable for industrial promotion. Summary of the Invention

[0005] The main objective of this invention is to provide a method for leaching beryllium from beryllium-containing sludge, aiming to solve the problems of high cost, high requirements for process equipment, and unsuitability for industrial application in the prior art for leaching beryllium from beryllium-containing sludge.

[0006] To achieve the above objectives, the present invention provides a method for beryllium leaching from beryllium-containing sludge, comprising the steps of:

[0007] After mixing the first regulator with beryllium-containing sludge, a first isothermal stirring treatment is performed to obtain a solid-liquid mixture. The first regulator is a solution containing carbonate ions.

[0008] A second regulator is then added dropwise to the solid-liquid mixture, followed by a second isothermal stirring treatment to obtain a beryllium-containing filtrate and a beryllium-free filter residue. The second regulator is an acid solution.

[0009] The processing temperatures for both the first and second constant-temperature stirring treatments are 25–75°C.

[0010] Furthermore, the first regulating agent is a sodium carbonate solution; the concentration of the sodium carbonate solution is 0.4–1.0 mol / L.

[0011] Furthermore, the mixing ratio of the sodium carbonate solution to the beryllium-containing sludge is 6–24 mL / g.

[0012] Further, the second regulator is a hydrochloric acid solution; the concentration of the hydrochloric acid solution is 2.5–3.0 mol / L.

[0013] Furthermore, the phase of the beryllium-containing sludge is calcium sulfate dihydrate loaded with beryllium hydroxide.

[0014] Furthermore, the beryllium-containing sludge is beryllium-containing waste residue generated from the industrial production of beryllium oxide.

[0015] Furthermore, the duration of the first isothermal stirring treatment is 15–240 min.

[0016] Furthermore, the duration of the second isothermal stirring treatment is 5 to 90 minutes.

[0017] Furthermore, the second isothermal stirring treatment further includes cooling treatment, solid-liquid separation treatment, and water washing treatment to obtain the beryllium-containing filtrate and the beryllium-de-precipitated filter residue.

[0018] Furthermore, the cooling process is slow air cooling; the solid-liquid separation process is centrifugation; and the water washing process involves washing the product with water and centrifuging it three times.

[0019] The beneficial effects achieved by this invention are as follows:

[0020] This invention provides a method for dissolving beryllium from beryllium-containing sludge. The method involves sequentially mixing the beryllium-containing sludge with a solution containing carbonate ions and an acid solution, followed by constant-temperature stirring at 25–75°C. This results in a beryllium-containing filtrate and a beryllium-free filter residue. This method offers mild processing conditions, requires no special pH conditions, and efficiently dissolves beryllium from the sludge at a relatively low temperature of 25–75°C. It simultaneously yields both the beryllium-containing filtrate and the beryllium-free filter residue, which is beneficial for the application of beryllium in subsequent processes and effectively detoxifies the beryllium residue obtained during production. Due to its low cost, low equipment requirements, and ease of operation, this method is highly applicable and suitable for industrial-scale promotion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 The image shows the XRD pattern of the beryllium-containing sludge in Example 1.

[0023] Figure 2 This is a schematic flowchart of the method for leaching beryllium from beryllium-containing sludge according to the present invention.

[0024] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of this invention is for describing specific implementations and not for limiting the scope of protection of this invention.

[0027] Unless otherwise defined, all technical and scientific terms used in this invention are consistent with the prior art known to those skilled in the art and the description of this invention. This invention can also be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention. It should be understood by those skilled in the art that, as an explanation of this application, without affecting the actual understanding of the technical solutions of this application, "2-Theta (degree)" can represent twice the diffraction angle, "Intensity" can represent intensity, and "XRD" can represent X-ray diffraction.

[0028] When numerical ranges are given in the examples, it should be understood that, unless otherwise stated in the invention, both endpoints of each range and any value between the two endpoints may be used. Test methods in the following examples that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers. Unless otherwise specified, all materials or reagents required in the following examples are commercially available.

[0029] To address the problems of high cost, demanding equipment requirements, and unsuitability for industrial application in existing technologies for leaching beryllium from beryllium-containing sludge, this invention provides a method for leaching beryllium from beryllium-containing sludge, comprising the following steps:

[0030] After mixing the first regulator with the beryllium-containing sludge, a first isothermal stirring treatment is performed to obtain a solid-liquid mixture. The first regulator is a solution containing carbonate ions. It should be noted that the beryllium content in the beryllium-containing sludge in this invention is 0.3–0.4 wt%. Specifically, by adding a solution containing carbonate ions, calcium sulfate dihydrate is converted into calcium carbonate, thus changing the main phase in which beryllium is present.

[0031] A second regulating agent is then added dropwise to the solid-liquid mixture, followed by a second isothermal stirring treatment to obtain a beryllium-containing filtrate and a beryllium-removed filter residue. The second regulating agent is an acid solution. Specifically, an acid solution is added dropwise to the solid-liquid mixture, followed by a second isothermal treatment.

[0032] This method offers mild processing conditions, requires no special pH settings, and efficiently dissolves beryllium from beryllium-containing sludge at relatively low temperatures of 25–75°C. It simultaneously yields both beryllium-containing filtrate and beryllium-removed filter residue, which is beneficial for subsequent beryllium applications and effectively detoxifies the beryllium residue obtained during production. Due to its low cost, minimal equipment requirements, and ease of operation, this method is highly applicable and suitable for industrial-scale promotion.

[0033] The first and second isothermal stirring treatments are both conducted at temperatures ranging from 25 to 75°C. These temperatures can be the same or different. Temperatures below 25°C affect molecular thermal motion, reducing the chemical reaction rate and hindering the reaction. Temperatures above 75°C increase energy consumption and waste heating energy. A schematic diagram of the process is shown below. Figure 2 As shown.

[0034] Furthermore, the first regulating agent is a sodium carbonate solution; the concentration of the sodium carbonate solution is 0.4–1.0 mol / L.

[0035] Since the beryllium content in beryllium-containing sludge is 0.3–0.4 wt%, and the beryllium exists in amorphous form as beryllium hydroxide, the equivalent beryllium hydroxide content is 1.43–1.91 wt%. When the solid-liquid mixture of sodium carbonate solution and beryllium-containing sludge is subjected to a first isothermal stirring treatment, the sodium carbonate solution fully converts the calcium sulfate dihydrate in the beryllium-containing sludge into calcium carbonate, releasing the beryllium trapped within and converting it into an acid-soluble state under mild conditions.

[0036] Because of K sp (CaCO3) <Ksp When sodium carbonate solution is added to (CaSO4), the system spontaneously undergoes the reaction: CaSO4·2H2O + Na2CO3 = CaCO3 + Na2SO4 + 2H2O. Furthermore, since hydrochloric acid solution is subsequently added for further reaction, using sodium carbonate solution converts calcium sulfate, which is very stable in acidic systems, into calcium carbonate, which can be dissolved by lower concentrations of acid. This makes the reaction conditions for the efficient release of beryllium from calcium sulfate more moderate, which is beneficial for subsequent reaction steps.

[0037] Furthermore, experimental verification has shown that, compared to ammonium carbonate solution, sodium carbonate solution not only does not produce an off-odor during production but also releases beryllium more completely. Specifically, industrial ammonium carbonate is actually a double salt of ammonium bicarbonate and ammonium carbamate, containing 31% ammonia and 56% carbon dioxide. It is unstable in air and gradually transforms into ammonium bicarbonate and ammonium carbamate. Its dried form readily decomposes at 58°C, releasing ammonia and carbon dioxide; its aqueous solution begins to decompose at 70°C, and it is unstable to both light and heat. When the theoretical amounts of ammonium carbonate and sodium carbonate obtained in the experiment are the same, the ammonium carbonate may have resulted in an incomplete double displacement reaction between calcium sulfate and carbonate ions due to impurities (compared to an equal amount of sodium carbonate), thus preventing the complete release of beryllium encapsulated within the calcium sulfate dihydrate.

[0038] Furthermore, adding 0.4–1.0 mol / L sodium carbonate solution to the system will not introduce excessive impurity elements, which is beneficial to improving the purity of the final product.

[0039] Furthermore, the mixing ratio of sodium carbonate solution to beryllium-containing sludge is 6–24 mL / g. Specifically, vacuum-dried beryllium-containing sludge is mixed with 0.4–1.0 mol / L sodium carbonate solution at a ratio of 6–24 mL / g and placed in a magnetically stirred water bath for a first constant-temperature stirring treatment. Only when the mixing ratio of sodium carbonate solution to beryllium-containing sludge is 6–24 mL / g can beryllium, iron, and aluminum in the beryllium-containing sludge dissolve normally. Therefore, to ensure the normal dissolution of beryllium, iron, and aluminum, the mixing ratio of sodium carbonate solution to beryllium-containing sludge should not be lower than 6 mL / g. In addition, too low a sodium carbonate solution volume may lead to insufficient stirring, reducing the contact opportunity between sodium carbonate and calcium sulfate dihydrate in the beryllium-containing sludge. A suitable mixing ratio of sodium carbonate solution to beryllium-containing sludge is a necessary factor in this invention.

[0040] Furthermore, the second regulator is a hydrochloric acid solution; the concentration of the hydrochloric acid solution is 2.5–3.0 mol / L.

[0041] Specifically, adding a 2.5–3.0 mol / L hydrochloric acid solution to the solid-liquid mixture creates an acidic system that facilitates the dissolution of sodium carbonate, resulting in efficient and mild beryllium release. Furthermore, adding a certain amount of 2.5–3.0 mol / L hydrochloric acid to the system allows it to react with calcium carbonate, preventing the re-encapsulation of beryllium during calcium carbonate formation. Under these acidic conditions, beryllium dissolves efficiently, while silica does not react with hydrochloric acid and only dissolves in small amounts.

[0042] Furthermore, the phase of the beryllium-containing sludge is calcium sulfate dihydrate loaded with beryllium hydroxide.

[0043] Furthermore, beryllium-containing sludge is beryllium-containing waste residue generated from the industrial production of beryllium oxide.

[0044] Furthermore, the duration of the first isothermal stirring treatment is 15–240 min. When the duration of the first isothermal stirring treatment is less than 15 min, calcium sulfate dihydrate cannot be completely converted into calcium carbonate; when the duration of the first isothermal stirring treatment is greater than 240 min, it will not only fail to improve the reaction efficiency but will also increase energy consumption.

[0045] Furthermore, the duration of the second isothermal stirring treatment is 5–90 min. When the duration of the second isothermal stirring treatment is less than 5 min, the added hydrochloric acid is insufficient to completely dissolve the calcium carbonate, resulting in the beryllium encapsulated in the calcium carbonate not being fully released; while when the duration of the second isothermal stirring treatment is greater than 90 min, it not only fails to improve the reaction effect but also increases energy consumption.

[0046] Furthermore, the second isothermal stirring process includes cooling, solid-liquid separation, and water washing to obtain a beryllium-containing filtrate and a beryllium-free filter residue.

[0047] Furthermore, the cooling process is slow air cooling; the solid-liquid separation process is centrifugation; and the water washing process involves washing with water and centrifuging the resulting product, which is then repeated three times.

[0048] Specifically, after the second constant temperature stirring treatment is completed, the mixture is allowed to cool to room temperature, and the solid-liquid mixture is separated by centrifugation. The filtrate is filtered out, and the filter residue is washed with water and centrifuged three times to obtain beryllium-containing filtrate and beryllium-de-precipitated filter residue (detoxified filter residue).

[0049] To further illustrate the present invention, the following examples are provided:

[0050] Example 1

[0051] Sampling and analysis of beryllium-containing sludge:

[0052] A sample of beryllium-containing sludge, dried and dehydrated from a factory, was digested with nitric acid and hydrochloric acid. The beryllium content in the dry sludge was found to be 0.35 wt%.

[0053] It should be noted that the distribution of beryllium in the beryllium-containing sludge is uneven, with the overall beryllium content ranging from 0.3% to 0.4 wt%. Subsequent calculations of the beryllium detoxification rate will be based on the 0.35 wt% obtained from this digestion, i.e., 3.5 g / kg.

[0054] The beryllium-containing sludge was found to contain mainly Ca, S, Si, O, Al, and Fe elements. Among them, Ca and S are mainly in the form of calcium sulfate dihydrate, and S mainly exists in the form of calcium silicate aluminum oxide.

[0055] The XRD pattern of the beryllium-containing sludge is as follows: Figure 1 As shown in the figure, the beryllium-containing sludge contains calcium sulfate dihydrate crystal phase.

[0056] Example 2

[0057] After vacuum drying, 5g of 1kg of beryllium-containing sludge from Example 1 was mixed with 100mL of a 1mol / L sodium carbonate solution and placed in a magnetically stirred water bath. The mixture was stirred thoroughly at 45°C for 4 hours. After the reaction, a solid-liquid mixture was obtained. 85mL of 3mol / L hydrochloric acid was slowly added dropwise, and the mixture was stirred thoroughly for 2 hours. After the reaction, the mixture was allowed to cool to room temperature and then separated by centrifugation to obtain a beryllium-containing filtrate and a beryllium-de-precipitated filter residue. The contents of beryllium, aluminum, iron, and silicon in the beryllium-containing filtrate were determined, and the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 95.55%, 85.87%, 84.98%, and 7.76%, respectively, with a leaching toxicity of 0.19mg / L.

[0058] Example 3

[0059] Compared to Example 2, only the mixing ratio of sodium carbonate solution and beryllium-containing sludge was reduced to 6 mL / g, while all other conditions remained unchanged.

[0060] Ultimately, the calculated leaching rates for beryllium, aluminum, iron, and silicon were 88.31%, 81.39%, 81.63%, and 7.93%, respectively.

[0061] Analysis example 1

[0062] Comparing the experimental results of Example 2 and Example 3, it can be found that Example 2 is more effective. This indicates that in order to ensure the proper dissolution of beryllium, iron, and aluminum, the mixing ratio of sodium carbonate solution to beryllium-containing sludge should not be too low. In addition, too low a volume of sodium carbonate solution may lead to insufficient stirring, reducing the contact opportunity between sodium carbonate and calcium sulfate dihydrate in the beryllium-containing sludge.

[0063] Example 4

[0064] Compared to Example 2, only the concentration of the sodium carbonate solution was adjusted to 0.9 mol / L, while all other conditions remained unchanged.

[0065] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 95.52%, 89.38%, 91.68%, and 7.62%, respectively, with a leaching toxicity of 0.1 mg / L.

[0066] Example 5

[0067] Compared to Example 2, only the concentration of the sodium carbonate solution was adjusted to 0.5 mol / L, while all other conditions remained unchanged.

[0068] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 78.31%, 77.51%, 80.55%, and 8.24%, respectively.

[0069] Example 6

[0070] Compared to Example 2, only the concentration of the sodium carbonate solution was adjusted to 0.7 mol / L, while all other conditions remained unchanged.

[0071] Finally, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 87.5%, 90.96%, 93.37%, and 7.76%, respectively.

[0072] Analysis example 2

[0073] Comparing the experimental results of Examples 2 and 3-6, it can be seen that when the sodium carbonate solution concentration is too low, the conversion of calcium sulfate dihydrate to calcium carbonate is incomplete, resulting in some beryllium remaining in the solid phase. Therefore, a suitable sodium carbonate concentration is one of the key factors in optimizing the reaction.

[0074] Example 7

[0075] Compared to Example 4, the only difference is that the reaction time in the magnetically stirred water bath at 45°C is changed to 15 minutes.

[0076] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 96.50%, 82.77%, 88.47%, and 7.20%, respectively, with a leaching toxicity of 0.05 mg / L.

[0077] Comparative Example 1

[0078] Compared to Example 4, the only difference is that the reaction time in the magnetically stirred water bath at 45°C is changed to 5 minutes.

[0079] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 85.79%, 82.98%, 93.31%, and 9.69%, respectively. However, XRD analysis of the products still revealed a peak for calcium sulfate dihydrate, indicating that beryllium in the beryllium-containing sludge was not completely leached.

[0080] Comparative Example 2

[0081] Compared to Example 4, the only difference is that the reaction time in the magnetically stirred water bath at 45°C is changed to 10 minutes.

[0082] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 91.83%, 89.29%, 94.23%, and 8.57%, respectively. However, XRD analysis of the products still revealed a peak in calcium sulfate dihydrate, indicating that beryllium in the beryllium-containing sludge was not completely leached.

[0083] Analysis example 3

[0084] Comparing the experimental results of Examples 4, 7, and Comparative Examples 1-2, it can be seen that the leaching rate of beryllium reaches 96.50% after 15 minutes of reaction. Before the reaction begins, the leaching rate of beryllium gradually increases with the extension of reaction time. XRD analysis of the products of Comparative Examples 1-2 revealed the presence of peaks for calcium sulfate dihydrate, indicating that the products were not amorphous and some calcium sulfate dihydrate remained unconverted into calcium carbonate. In Example 7, when the stirring reaction time was increased to 15 minutes, the product was found to be amorphous according to XRD analysis. Therefore, appropriately extending the reaction time helps promote the conversion of calcium sulfate into calcium carbonate.

[0085] Example 8

[0086] Compared to Example 7, only the concentration of hydrochloric acid was adjusted to 2.5 mol / L, while all other conditions remained unchanged.

[0087] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 90.86%, 72.39%, 84.45%, and 3.20%, respectively.

[0088] Comparative Example 3

[0089] Compared to Example 7, only the concentration of hydrochloric acid was adjusted to 1 mol / L, while all other conditions remained unchanged.

[0090] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 1.53%, 0.81%, 0.82%, and 7.23%, respectively.

[0091] Comparative Example 4

[0092] Compared to Example 7, only the concentration of hydrochloric acid was adjusted to 2 mol / L, while all other conditions remained unchanged.

[0093] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 4.01%, 0.07%, 0.63%, and 1.58%, respectively.

[0094] Analysis example 4

[0095] Comparing the experimental results of Examples 7-8 and Comparative Examples 3-4, it can be seen that when the hydrochloric acid concentration is too low, only a small portion of the calcium carbonate converted from calcium sulfate dihydrate is dissolved, and the calcium carbonate cannot be dissolved efficiently, resulting in most of the beryllium remaining in the solid phase. When the hydrochloric acid solution concentration is between 2.5 and 3 mol / L, calcium carbonate can be dissolved efficiently. When the hydrochloric acid solution concentration is increased to 3 mol / L as in Example 7, the beryllium leaching rate increases sharply, and the hydrochloric acid efficiently releases the beryllium sealed in calcium carbonate, indicating that a suitable hydrochloric acid concentration is one of the key factors of this invention.

[0096] Example 9

[0097] Compared to Example 4, only the reaction temperature in the magnetically stirred water bath was changed, i.e., the mixture was stirred thoroughly at 35°C.

[0098] Ultimately, the calculated values ​​were 96.77%, 86.07%, 90.16%, and 9.19%, with a leaching toxicity of 0.08 mg / L.

[0099] Example 10

[0100] Compared to Example 4, only the reaction temperature in the magnetically stirred water bath was changed, i.e., the mixture was stirred thoroughly at 25°C.

[0101] Ultimately, the calculated percentages were 91.55%, 81.01%, 86.43%, and 8.63%.

[0102] Example 11

[0103] Compared to Example 4, only the reaction temperature in the magnetically stirred water bath was changed, i.e., the mixture was stirred thoroughly at 55°C.

[0104] Ultimately, the calculated percentages were 96.24%, 90.87%, 95.52%, and 8.51%.

[0105] Analysis example 5

[0106] Comparing the experimental results of Examples 4 and 9-11, it can be seen that when the temperature is 25°C as in Example 10, the beryllium leaching rate increases with the increase of temperature. When the temperature is raised to 35°C as in Example 9, the leaching rate can reach 96.77%. If the temperature is further increased (as in Examples 4 and 11), the leaching rate remains almost unchanged.

[0107] Example 12

[0108] Compared to Example 8, the only change was the reaction time after adding hydrochloric acid, i.e., 1 mol / L hydrochloric acid was slowly added dropwise and the reaction was stirred thoroughly for 5 minutes.

[0109] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 96.47%, 91.11%, 91.36%, and 8.73%, respectively, with a leaching toxicity of 0.01 mg / L.

[0110] Example 13

[0111] Compared to Example 8, the only change was the reaction time after adding hydrochloric acid, i.e., 1 mol / L hydrochloric acid was slowly added dropwise and the reaction was stirred thoroughly for 40 minutes.

[0112] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 96.27%, 91.46%, 93.39%, and 9.01%, respectively.

[0113] Analysis example 6

[0114] Comparing the experimental results of Examples 8 and 12-13, it can be seen that when the hydrochloric acid stage reaction proceeds to 5 minutes in Example 12, the leaching rate of beryllium reaches 96.47%. As the reaction time is extended (as in Examples 8 and 13), the leaching rate of beryllium remains almost unchanged. This indicates that the hydrochloric acid stage reaction can efficiently release beryllium from the intermediate product within 5 minutes.

[0115] Comparative Example 5

[0116] Compared to Example 2, the only difference is that the sodium carbonate solution is replaced with an ammonium carbonate solution, i.e., 5g is mixed with 100mL of an ammonium carbonate solution with a concentration of 1mol / L.

[0117] Ultimately, the leaching rates of beryllium, aluminum, iron, and silicon were calculated to be 81.86%, 72.23%, 73.17%, and 7.40%, respectively.

[0118] Analysis example 7

[0119] Comparing the experimental results of Example 2 and Comparative Example 5, it can be seen that using sodium carbonate solution as the first regulator, the conversion of calcium sulfate dihydrate to calcium carbonate is more complete, which is beneficial for the efficient release of beryllium from calcium carbonate by hydrochloric acid in the next step.

[0120] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for dissolving beryllium in a beryllium-containing sludge, characterized by, The method comprises the steps of: mixing a first control agent with the beryllium-containing sludge, and then performing first constant-temperature stirring treatment to obtain a solid-liquid mixture; the first control agent is a sodium carbonate solution; the concentration of the sodium carbonate solution is 0.4-1.0 mol / L; the mixing ratio of the sodium carbonate solution to the beryllium-containing sludge is 6-24 mL / g; then, adding a second control agent dropwise into the solid-liquid mixture, and performing second constant-temperature stirring treatment; the second constant-temperature stirring treatment is followed by cooling treatment, solid-liquid separation treatment and water washing treatment to obtain a beryllium-containing filtrate and a beryllium-removed filter residue; the second control agent is a hydrochloric acid solution; the concentration of the hydrochloric acid solution is 2.5-3.0 mol / L; wherein, the phase of the beryllium-containing sludge is beryllium hydroxide-loaded calcium sulfate dehydrate; the treatment temperature of the first constant-temperature stirring treatment and the second constant-temperature stirring treatment is 25-75 ℃; the time length of the first constant-temperature stirring treatment is 15-240 min; and the time length of the second constant-temperature stirring treatment is 5-90 min.

2. The method of claim 1, wherein the beryllium elution from the beryllium-containing sludge is characterized by, The beryllium-containing sludge is a beryllium-containing waste residue generated in the industrial production of beryllium oxide.

3. The method of claim 1, wherein the beryllium-containing sludge is a sludge from a nuclear reactor. The cooling treatment is air slow cooling; the solid-liquid separation treatment is centrifugal treatment; and the water washing treatment is repeated three times.

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