A method for leaching gallium from lime mud

Abstract

The application relates to a method for leaching gallium from lime residue, which comprises the following steps: adding a composite alkali liquor into lime residue to obtain a slurry; wherein the components of the composite alkali liquor include alkali metal hydroxide and alkali metal carbonate; and heating the slurry to leach gallium and obtain a gallium-containing mixed slurry. The application improves the leaching rate of gallium by using a composite alkali liquor and a combined leaching process, and solves the technical problem of poor economic efficiency of the existing gallium leaching process from lime residue. Compared with the prior art, the method avoids the defects of high equipment requirement of the traditional alkali leaching process, and the shortcomings of large acid consumption of the acid leaching process, high content of impurity elements such as calcium in the leaching solution, and complex solution purification process.

Description

Technical Field

[0001] This application relates to the field of solid waste recycling technology, and in particular to a method for leaching gallium from lime slag. Background Technology

[0002] Gallium is a rare metallic element, and due to its inherent properties, it is mainly used in high-tech fields such as LEDs, wireless communications, permanent magnet materials, and photovoltaics. Currently, the solid residue produced during the gallium enrichment solution purification process in gallium production, which involves adding lime to precipitate vanadium, is called vanadium-precipitated lime slag. The gallium content in lime slag ranges from 0.3% to 4.0%, which is much higher than that of ordinary gallium ore resources, making it valuable for recycling.

[0003] However, the existing alkaline process for leaching gallium from vanadium-containing lime slag has high equipment requirements, resulting in high costs; or acid leaching of vanadium-containing lime slag not only results in high impurity content in the leaching solution and complex subsequent solution purification processes, but also generates a large amount of calcium sulfate waste residue. Summary of the Invention

[0004] This application provides a method for leaching gallium from lime slag to solve the technical problem of poor economic efficiency in existing gallium leaching processes from lime slag.

[0005] In a first aspect, this application provides a method for leaching gallium from lime slag, the method comprising:

[0006] A composite alkaline solution is added to lime slag to obtain a slurry; wherein the components of the composite alkaline solution include alkali metal hydroxides and alkali metal carbonates.

[0007] The slurry is heated to leach gallium, resulting in a gallium-containing mixed slurry.

[0008] Optionally, the alkali metal hydroxide includes at least one of the following: sodium hydroxide and potassium hydroxide.

[0009] Optionally, relative to 1L of the composite alkaline solution, the sodium hydroxide is ≤260g, and / or,

[0010] The amount of potassium hydroxide is ≤220g relative to 1L of the composite alkaline solution.

[0011] Optionally, the alkali metal carbonate includes at least one of the following: sodium carbonate and potassium carbonate.

[0012] Optionally, relative to 1L of the composite alkaline solution, the sodium carbonate is 80g to 400g, and / or,

[0013] The amount of potassium carbonate is 110g to 460g relative to the 1L of the composite alkaline solution.

[0014] Optionally, the composite alkaline solution is 1.5L to 6L relative to 1kg of lime slag.

[0015] Optionally, heating the slurry to leach gallium and obtain a gallium-containing mixed slurry includes:

[0016] The slurry is heated to leach gallium, and the leaching temperature is controlled to obtain a gallium-containing mixed slurry.

[0017] Optionally, the leaching temperature is 60℃~120℃.

[0018] Optionally, the leaching time is 0.5h to 3.0h.

[0019] Optionally, the step of heating the slurry to leach gallium and obtain a gallium-containing mixed slurry further includes:

[0020] The gallium-containing mixed slurry is filtered to obtain a gallium-containing leachate and filter residue; wherein, by mass fraction, the filter residue comprises: 45%–50% calcium oxide, 0.3%–1.0% sodium oxide, and 1.3%–1.6% magnesium oxide.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art:

[0022] The method for leaching gallium from lime slag provided in this application utilizes alkali metal hydroxides, which are strong bases with good leaching effect on lime slag and promote gallium leaching. Alkali metal carbonates, being strong base-weak acid salts, reduce the leaching of other impurities and further promote effective gallium leaching. The combination of alkali metal hydroxides and carbonates has a synergistic effect and no side reactions occur. It can leach gallium to a large extent while providing mild reaction conditions, reducing energy consumption, and leaching less of other impurities. This composite alkaline solution, combined with subsequent leaching processes, improves the gallium leaching rate and solves the technical problem of poor economic efficiency in existing gallium leaching processes from lime slag. Compared with existing technologies, it avoids the disadvantages of traditional acid leaching processes, such as high acid consumption, high content of impurities like calcium in the leaching solution, and complex subsequent solution purification processes, as well as the high equipment requirements of alkaline leaching processes. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic flowchart illustrating a method for leaching gallium from lime slag, provided as an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0028] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0029] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0030] Firstly, this application provides a method for leaching gallium from lime slag, see [link to relevant documentation]. Figure 1 The method includes:

[0031] S1. Add a composite alkaline solution to lime slag to obtain a slurry; wherein the components of the composite alkaline solution include alkali metal hydroxides and alkali metal carbonates.

[0032] In the embodiments of this application, the alkali metal hydroxide is a strong base, possessing both solubility and strong alkalinity, resulting in good leaching effect on lime slag and promoting gallium leaching. The alkali metal carbonate is a strong base-weak acid salt, which reduces the leaching of other impurities and promotes effective gallium leaching. The combination of alkali metal hydroxide and alkali metal carbonate has a synergistic effect and no side reactions occur. It can leach gallium to a large extent while providing mild reaction conditions, reducing energy consumption, and leaching fewer other impurities.

[0033] In some embodiments, the alkali metal hydroxide includes at least one of the following: sodium hydroxide and potassium hydroxide.

[0034] In some embodiments, the sodium hydroxide is ≤260g relative to 1L of the composite alkaline solution, and / or,

[0035] The amount of potassium hydroxide is ≤220g relative to 1L of the composite alkaline solution.

[0036] In some embodiments, the alkali metal carbonate includes at least one of the following: sodium carbonate and potassium carbonate.

[0037] In some embodiments, the sodium carbonate is 80g to 400g relative to 1L of the composite alkaline solution, and / or,

[0038] The amount of potassium carbonate is 110g to 460g relative to the 1L of the composite alkaline solution.

[0039] In some embodiments, the composite alkaline solution is 1.5L to 6L relative to 1kg of lime slag.

[0040] In this embodiment, the alkali metal hydroxide can be at least one of sodium hydroxide and potassium hydroxide, which can leach gallium to a large extent without producing side reactions. Sodium hydroxide and potassium hydroxide are readily available, inexpensive, and commonly used strong bases. The alkali metal carbonate can be at least one of sodium carbonate and potassium carbonate, which can reduce the difficulty of the leaching reaction, leach fewer other impurities, and avoid side reactions. Sodium carbonate and potassium carbonate are readily available, inexpensive, and commonly used strong base-weak acid salts. Therefore, the components of the above-mentioned composite alkaline solution can be a mixed solution of sodium hydroxide and sodium carbonate, or a mixed solution of potassium hydroxide and sodium carbonate, or a mixed solution of sodium hydroxide, potassium hydroxide, and sodium carbonate, or a mixed solution of potassium carbonate, potassium hydroxide, and sodium hydroxide, etc., which can leach gallium to a large extent, provide mild reaction conditions, and leach fewer other impurities. In addition, this method is particularly suitable for lime slag generated from gallium production impurity removal.

[0041] Furthermore, controlling the content of components in the composite alkaline solution is crucial to ensuring the gallium leaching rate. Excessive sodium hydroxide or potassium hydroxide content can lead to overly high alkalinity, resulting in excessive leaching of other impurities alongside gallium. Appropriate amounts of sodium carbonate or potassium carbonate can, to some extent, enhance the leaching of gallium and inhibit the leaching of other impurity elements. Specifically, relative to 1L of the aforementioned composite alkaline solution, the sodium hydroxide can be 260g, 255g, 250g, etc.; relative to 1L of the aforementioned composite alkaline solution, the potassium hydroxide can be 220g, 180g, 160g, etc.; relative to 1L of the aforementioned composite alkaline solution, the sodium carbonate can be 80g, 90g, 100g, 110g, 120g, 130g, 140g, etc.; relative to 1L of the aforementioned composite alkaline solution, the potassium carbonate can be 110g, 150g, 200g, 250g, 300g, 350g, 400g, 460g, etc. The amount of composite alkaline solution used is controlled to ensure the gallium leaching rate. Excessive use of the composite alkaline solution will increase costs to some extent, while the improvement in gallium leaching effect will not be significant. Insufficient use will reduce the gallium leaching rate to some extent. Specifically, relative to 1 kg of the aforementioned lime slag, the aforementioned composite alkaline solution can be 1.5 L, 2 L, 2.5 L, 3 L, 3.5 L, 4 L, 4.5 L, 5 L, 5.5 L, 6 L, etc.

[0042] S2. The slurry is heated to leach gallium, resulting in a gallium-containing mixed slurry.

[0043] In some embodiments, heating the slurry to leach gallium and obtain a gallium-containing mixed slurry includes:

[0044] The slurry is heated to leach gallium, and the leaching temperature is controlled to obtain a gallium-containing mixed slurry.

[0045] In some embodiments, the leaching temperature is 60°C to 120°C.

[0046] In this embodiment, the leaching temperature is controlled to ensure the effective leaching of gallium. If the leaching temperature is too low, the leaching effect of gallium may not be optimized to a certain extent. Specifically, the leaching temperature can be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, etc.; preferably, the leaching temperature can be 70°C to 110°C.

[0047] In some embodiments, the leaching time is 0.5h to 3.0h.

[0048] In this embodiment, the leaching time is controlled to ensure the leaching effect and purity of gallium. If the leaching time is too long, coexisting impurities will be leached out to some extent, increasing the cost of subsequent impurity removal; if the leaching time is too short, the gallium leaching rate will be reduced to some extent, resulting in poor economic efficiency. Specifically, the leaching time can be 0.5h, 1.0h, 1.5h, 2.0h, 2.5h, 3.0h, etc.

[0049] In some embodiments, the heating of the slurry to leach gallium, resulting in a gallium-containing mixed slurry, further includes:

[0050] The gallium-containing mixed slurry is filtered to obtain a gallium-containing leachate and filter residue; wherein, by mass fraction, the filter residue comprises: 45%–50% calcium oxide, 0.3%–1.0% sodium oxide, and 1.3%–1.6% magnesium oxide.

[0051] In the embodiments of this application, the composition of the filter residue is close to that of the raw materials used in cement production in cement plants, and therefore it can be used as a raw material for cement production in cement plants. Specifically, please refer to Table 3.

[0052] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0053] The chemical composition of lime slag 1 used in Examples 1-7 is shown in Table 1:

[0054] Table 1. Chemical composition (wt%) of lime slag 1

[0055] Main substances <![CDATA[Al2O3]]> <![CDATA[SiO2]]> <![CDATA[Na2O]]> CaO Ga V content(%) 17.77 0.85 1.53 46.16 2.08 0.17

[0056] Example 1

[0057] (1) Prepare a compound alkaline solution with a sodium carbonate concentration of 200 g / L and a potassium hydroxide concentration of 40 g / L;

[0058] (2) Take 1 kg of lime residue 1, add 3 L of alkaline solution to it, and stir thoroughly to obtain the original slurry;

[0059] (3) The original slurry was fed into the reactor, heated to 90°C, and reacted for 2.0 h to obtain a gallium-containing mixed slurry;

[0060] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0061] Example 2

[0062] (1) Prepare a compound alkaline solution containing 350 g / L sodium carbonate, 20 g / L sodium hydroxide and 20 g / L potassium hydroxide;

[0063] (2) Take 1 kg of lime residue 1, add 4 L of alkaline solution to it, and stir thoroughly to obtain the original slurry;

[0064] (3) The original slurry was fed into the reactor, heated to 95°C, and reacted for 2.5 h to obtain a gallium-containing mixed slurry;

[0065] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0066] Example 3

[0067] (1) Prepare a compound alkaline solution containing 80 g / L sodium carbonate, 200 g / L sodium hydroxide and 100 g / L potassium hydroxide;

[0068] (2) Take 1 kg of lime residue 1, add 3 L of alkaline solution to it, and stir thoroughly to obtain the original slurry;

[0069] (3) The original slurry was fed into the reactor, heated to 120°C, and reacted for 0.5 h to obtain a gallium-containing mixed slurry;

[0070] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0071] Example 4

[0072] (1) Prepare a composite alkaline solution with a sodium carbonate concentration of 400 g / L, a potassium hydroxide concentration of 15 g / L, and a sodium hydroxide concentration of 260 g / L;

[0073] (2) Take 1 kg of lime slag 1, add 1.5 L of alkaline solution to it, and stir thoroughly to obtain the original slurry;

[0074] (3) The original slurry was fed into the reactor, heated to 60°C, and reacted for 1.0 h to obtain a gallium-containing mixed slurry;

[0075] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0076] Example 5

[0077] (1) Prepare a compound alkaline solution containing 110 g / L potassium carbonate and 260 g / L sodium hydroxide;

[0078] (2) Take 1 kg of lime residue 1, add 6 L of alkaline solution to it, and after thorough stirring, obtain the original slurry;

[0079] (3) The original slurry was fed into the reactor, heated to 100°C, and reacted for 0.5 h to obtain a gallium-containing mixed slurry;

[0080] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0081] Example 6

[0082] (1) Prepare a compound alkaline solution containing 80 g / L sodium carbonate, 100 g / L potassium hydroxide and 180 g / L sodium hydroxide.

[0083] (2) Take 1 kg of lime slag 1, add 3.5 L of alkaline solution to it, and after thorough stirring, obtain the original slurry.

[0084] (3) The original slurry is fed into the reactor and heated to 70°C. The reaction is carried out for 3.0 h to obtain a gallium-containing mixed slurry.

[0085] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0086] Example 7

[0087] (1) Prepare a compound alkaline solution containing 110 g / L potassium carbonate, 220 g / L potassium hydroxide and 80 g / L sodium hydroxide.

[0088] (2) Take 1 kg of lime slag 1, add 3.5 L of alkaline solution to it, and after thorough stirring, obtain the original slurry.

[0089] (3) The original slurry was pumped into the reactor, heated to 85°C, and reacted for 3.0 h to obtain a gallium-containing mixed slurry.

[0090] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0091] The chemical composition of lime slag 2 used in Examples 8-10 is shown in Table 2:

[0092] Table 2 Chemical composition (wt%) of lime slag 2

[0093] Main substances <![CDATA[Al2O3]]> <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> CaO Ga V content(%) 22.17 0.79 0.8 45.22 0.55 0.084

[0094] Example 8

[0095] (1) Prepare a composite alkaline solution containing 200 g / L sodium carbonate and 60 g / L sodium hydroxide;

[0096] (2) Take 1 kg of lime residue 2, add 5 L of alkaline solution to it, and stir thoroughly to obtain the original slurry;

[0097] (3) The original slurry was fed into the reactor and heated to 85°C. The reaction was carried out for 2.0 h to obtain a gallium-containing mixed slurry.

[0098] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0099] Example 9

[0100] (1) Prepare a compound alkaline solution containing 350 g / L sodium carbonate and 60 g / L potassium hydroxide;

[0101] (2) Take 1 kg of lime residue 2, add 4 L of alkaline solution to it, and after thorough stirring, obtain the original slurry;

[0102] (3) The original slurry was fed into the reactor, heated to 100°C, and reacted for 2.5 h to obtain a gallium-containing mixed slurry;

[0103] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0104] Example 10

[0105] (1) Prepare a compound alkaline solution containing 460 g / L potassium carbonate, 100 g / L potassium hydroxide and 30 g / L sodium hydroxide.

[0106] (2) Take 1 kg of lime residue 2, add 3.5 L of alkaline solution to it, and after thorough stirring, obtain the original slurry.

[0107] (3) The original slurry is fed into the reactor and heated to 75°C. The reaction is carried out for 3.0 h to obtain a gallium-containing mixed slurry.

[0108] (4) The gallium-containing mixed slurry is filtered to obtain gallium-containing leachate and filter residue. The gallium-containing leachate can be returned to the gallium production process.

[0109] The filter residues from Examples 1 to 10 were dried and their main elemental composition was determined. The composition (wt%) is shown in Table 3.

[0110] Table 3. Composition of filter residue (wt%)

[0111] Serial Number CaO <![CDATA[Na2O]]> MgO Example 1 48.82 0.34 1.60 Example 2 49.35 0.51 1.57 Example 3 45.35 0.82 1.46 Example 4 48.82 1.00 1.58 Example 5 48.02 0.46 1.43 Example 6 47.61 0.87 1.48 Example 7 48.33 0.65 1.36 Example 8 48.22 0.30 1.45 Example 9 49.13 0.42 1.40 Example 10 49.20 0.36 1.36

[0112] The gallium content in the leaching residue of Examples 1 to 10 was determined, and the gallium leaching rate was calculated. The gallium leaching rate is shown in Table 4.

[0113] Table 4. Gallium content and gallium leaching rate in filter residue

[0114]

[0115]

[0116] Comparative Example 1

[0117] The leaching method provided in Chinese invention patent application CN114507778A includes the following steps: 1 kg of lime slag is taken, 3000 mL of water and 800 mL of 98% concentrated sulfuric acid are added, and the mixture is reacted at 60℃ for 30 min. After filtration, calcium sulfate residue and filtrate are obtained, and the gallium leaching rate reaches 95%. Due to the high impurity content in the leaching solution, it must undergo a purification process before being returned to the gallium production process. The subsequent purification and return of the leaching solution to the gallium production process is as follows: NaOH is added to the above filtrate to adjust the pH to 2-3, and then vanadium is adsorbed using vanadium ion exchange resin to produce vanadium adsorption tail liquid. The acidity of the obtained vanadium adsorption tail liquid is adjusted with hydrochloric acid to make the hydrogen ion concentration 3-6 mol / L. Then gallium is adsorbed using gallium ion exchange resin. The saturated gallium ion exchange resin is desorbed with gallium desorption solution to obtain gallium-rich solution, which is returned to the original gallium recovery system.

[0118] Using the technical solution of this application embodiment, the gallium leaching rate in lime slag is not less than 90% (see Table 4). Moreover, the gallium leaching solution can be directly returned to the gallium production process without purification treatment. Therefore, compared with the lime slag leaching process disclosed in CN114507778A, the process flow is simpler and the cost of gallium recovery from lime slag is lower.

[0119] Comparative Example 2

[0120] The method for treating lime residue generated from purifying gallium enrichment solution, as provided in Chinese invention patent application CN103740940A, includes the following steps: preparing an alkaline solution with a sodium oxide concentration of 200 g / L using sodium hydroxide; adding 10 liters of the alkaline solution and 3 kg of lime residue 1 to a high-pressure reactor; setting the leaching temperature to 150°C; maintaining the temperature for 1.0 h after reaching the set temperature; and filtering the leached slurry to obtain a gallium-containing leaching solution with a gallium leaching rate of 85.6%.

[0121] Comparative Example 3

[0122] Prepare an alkaline solution containing 80 g / L sodium carbonate, 230 g / L sodium hydroxide, and 100 g / L potassium hydroxide; take 1 kg of lime slag 1, add 3 L of the alkaline solution to it, and stir thoroughly to obtain the raw slurry; pump the raw slurry into a reactor, heat it to 120°C, and react for 0.5 h. The gallium leaching rate can reach 92%, and the above gallium leaching solution can be directly returned to the gallium production process.

[0123] Comparative Example 4

[0124] Prepare an alkaline solution containing 360 g / L sodium carbonate and 60 g / L potassium hydroxide; take 1 kg of lime slag 1, add 3 L of alkaline solution to it, and stir thoroughly to obtain the original slurry; pump the original slurry into the reactor, heat to 100℃, and react for 1.0 h. The gallium leaching rate can reach 95%, and the above gallium leaching solution can be directly returned to the gallium production process.

[0125] Analyzing Examples 1-10 and Comparative Examples 1-4, the technical advantages of the embodiments of this application are more obvious: under similar leaching conditions, the gallium leaching rate is higher; and the gallium leaching rate is even higher at lower leaching temperatures. Specifically, the acid-based treatment of lime slag in Comparative Example 1 has high acid consumption, a complex solution purification process, and easily generates a large amount of calcium sulfate waste residue, making it difficult to integrate with existing processes. The high-pressure alkaline leaching method used in Comparative Example 2 requires a leaching temperature of 150°C, placing high demands on leaching equipment and making it less acceptable to enterprises. Examples 1-10 and Comparative Examples 3 and 4 of this application utilize the technical solutions of this application, enabling the leaching of lime slag at lower temperatures and atmospheric pressures, providing milder leaching conditions, and achieving a high gallium leaching rate. In summary, the technical solution proposed in this application for leaching gallium from vanadium-precipitated lime slag used in gallium production is simpler, has milder conditions, and is easily integrated with existing production processes, facilitating its widespread application.

[0126] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for leaching gallium from lime slag, characterized in that, The method includes: A composite alkaline solution is added to lime slag to obtain a slurry; wherein the composite alkaline solution is composed of alkali metal hydroxides and alkali metal carbonates, the alkali metal hydroxides being sodium hydroxide and / or potassium hydroxide, and the alkali metal carbonates being sodium carbonate and / or potassium carbonate. The slurry is heated at atmospheric pressure and a temperature of 60°C to 120°C to leach gallium, resulting in a gallium-containing mixed slurry. The lime residue is the solid residue produced during the process of adding lime to the gallium enrichment solution for gallium production to purify vanadium precipitation. Relative to 1L of compound alkaline solution, the sodium hydroxide is ≤260g, the potassium hydroxide is ≤220g, the sodium carbonate is 80g~400g, and the potassium carbonate is 110g~460g.

2. The method according to claim 1, characterized in that, The amount of the composite alkaline solution is 1.5L to 6L relative to 1kg of lime slag.

3. The method according to claim 1, characterized in that, The leaching time is 0.5h to 3.0h.

4. The method according to claim 1, characterized in that, The slurry is heated to make Gallium leaching yields a gallium-containing mixed slurry, which then includes: The gallium-containing mixed slurry is filtered to obtain a gallium-containing leachate and filter residue; wherein, by mass fraction, The filter residue comprises: 45%~50% calcium oxide, 0.3%~1.0% sodium oxide, and 1.3%~1.6% magnesium oxide.

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