Method for preparing high-purity gallium tetrachloride based on continuous flow micro-reaction

Abstract

The invention discloses a method for preparing high-purity gallium tetrachloride based on a continuous flow micro-reaction, and relates to the technical field of rare metal compound preparation, according to the method, gallium-containing solid recovered matter is used as a raw material, and the high-purity gallium tetrachloride is prepared through the steps of crushing leaching, extraction purification, reverse extraction crystallization, continuous flow chlorination and the like in sequence; the method is characterized in that a composite extraction agent prepared by performing esterification reaction on a main extraction agent and a synergistic complexing component through a dehydration condensation agent is adopted to perform high-selectivity extraction on the leachate, so that efficient separation of gallium from impurities such as iron and aluminum is realized; then, the obtained high-purity gallium precursor is placed in a continuous flow micro-reaction container to be subjected to a chlorination reaction with chlorine; according to the method, high-purity metal gallium is replaced by waste, so that the cost is greatly reduced; the composite extractant ensures high purity of the raw materials; the continuous flow micro-reaction technology ensures the safety, high efficiency and controllability of the chlorination process, and is suitable for large-scale production of high-purity gallium tetrachloride.

Description

Technical Field

[0001] This invention relates to the field of rare metal compound preparation technology, and in particular to a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction. Background Technology

[0002] High-purity gallium tetrachloride (GaTe) is a key precursor for the preparation of third-generation semiconductor materials such as gallium arsenide (GaAs) and gallium nitride (GaN). Currently, the industrial production of high-purity GaTe is mainly achieved through the direct chlorination method, which uses high-purity (typically ≥99.99%) metallic gallium as a raw material and reacts it with chlorine gas at high temperatures. This method has significant drawbacks: First, high-purity gallium is extremely expensive, resulting in high production costs. Secondly, the chlorination reaction of metallic gallium is highly exothermic, and traditional batch reactors suffer from problems such as low heat and mass transfer efficiency, easy local overheating, numerous side reactions, and significant safety hazards, making it difficult to control product quality and consistency.

[0003] To reduce reliance on primary gallium metal, the industry has begun to focus on recovering gallium from gallium-containing solid waste. However, such recovered materials have complex compositions, often containing large amounts of impurity ions such as iron (Fe), aluminum (Al), and copper (Cu), and their chemical properties differ from those of gallium-containing solid waste. Similar to gallium, separation and purification are extremely difficult. Traditional separation methods such as precipitation and extraction have limited selectivity, making it difficult to obtain gallium intermediates that meet semiconductor-grade purity requirements. If the crude product with low purity is directly chlorinated, the subsequent purification process is lengthy, the yield is low, and the purity of the final product is difficult to guarantee.

[0004] Therefore, developing a method to efficiently and selectively extract gallium from complex waste and couple it with a safe and efficient conversion process to directly prepare ultra-high purity gallium tetrachloride is of great significance for reducing the cost of semiconductor raw materials and realizing resource recycling. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction, which solves the problems mentioned in the background art.

[0006] This invention is achieved as follows: a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction, comprising the following steps; S1. Take gallium-containing solid recycled material and crush and grind it; S2. The gallium-containing solid recyclable material that has been crushed and ground is leached with an acid solution to obtain a gallium-containing leachate. S3. The leachate is extracted and purified using an organic solvent to obtain the loaded solution. An organic phase, wherein the organic phase contains a composite extractant; S4. Back-extract the load using a low-concentration acid solution. The organic phase must have high purity. The back-extraction solution; S5. Evaporate and crystallize the back-extraction solution obtained in step S4 to obtain a high-purity gallium precursor. S6. The high-purity gallium precursor is introduced into a continuous flow microreactor to carry out a chlorination reduction reaction to generate gallium tetrachloride. S7. The reaction product obtained in step S6 is separated and purified to obtain high-purity gallium tetrachloride.

[0007] A further technical solution of the present invention is: in step S1, the gallium-containing solid recyclable material is selected from gallium arsenide waste, gallium nitride waste, or copper indium gallium selenide photovoltaic waste.

[0008] A further technical solution of the present invention is: in step S3, the composite extractant includes a main extractant and a synergistic complexing component.

[0009] A further technical solution of the present invention is that the main extractant is selected from at least one of phosphoric acid extractants, phosphonic acid extractants, and amine extractants; And / or the synergistic complexing component is selected from at least one of β-diketone compounds, hydroxycarboxylic acid compounds, amino acid compounds, and nitrogen-containing heterocyclic compounds.

[0010] A further technical solution of the present invention is as follows: the preparation method of the composite extractant is as follows: The main extractant and the synergistic complexing component are mixed in an organic diluent at a volume ratio of (14~19):(1~6), and a dehydrating condensing agent is added to carry out an esterification reaction to obtain the final product.

[0011] A further technical solution of the present invention is that the dehydrating condensing agent is selected from one of dicyclohexylcarbodiimide and diisopropylcarbodiimide.

[0012] A further technical solution of the present invention is: in step S5, the high-purity gallium precursor is anhydrous gallium chloride, gallium oxide, an organic complex solid of gallium, or a combination thereof.

[0013] A further technical solution of the present invention is: in step S4, the low-concentration acid solution is a hydrochloric acid solution with a concentration in the range of 0.5 to 2.0 mol / L.

[0014] A further technical solution of the present invention is: in step S6, the continuous flow microreactor is a microchannel reactor or a tubular reactor.

[0015] A further technical solution of the present invention is that the material of the continuous flow microreactor is Hastelloy or quartz; And / or the fluoropolymer material lining the continuous flow microreactor.

[0016] The beneficial effects of this invention are: 1. This invention completely replaces expensive high-purity metallic gallium with inexpensive and readily available gallium-containing solid recyclables, thereby reducing raw material costs by more than 60% and resulting in significant economic benefits.

[0017] 2. This invention employs a composite extractant prepared through a dehydration condensation reaction, which enhances the synergistic effect between the main extractant and the co-complexing components, thereby significantly improving the extraction efficiency. Its selective recognition capability enables it to deeply remove key impurities such as iron and copper from complex leachates, resulting in higher quality extracts. The solution has high purity.

[0018] 3. In this invention, the traditional batch-type chlorination process is abandoned, and a continuous flow microreactor is introduced for the chlorination reaction. Because the microreactor has a very large specific surface area, its mass and heat transfer efficiency is extremely high, enabling precise control of reaction conditions and completely eliminating the risk of heat accumulation, making the highly exothermic chlorination process inherently safe. Simultaneously, this technology achieves continuous operation from extraction and purification to chlorination conversion, resulting in high production efficiency, stable product quality, and ease of large-scale scaling. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction provided by the present invention. Detailed Implementation

[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0021] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0022] A method for preparing high-purity gallium tetrachloride based on continuous flow microreaction specifically includes the following steps: (1) Take gallium-containing solid recyclable material (selected from gallium arsenide waste, gallium nitride waste or copper indium gallium selenide photovoltaic waste), use a jaw crusher for coarse crushing, and then transfer it to a planetary ball mill for grinding into powder with a particle size of less than 150 micrometers.

[0023] Crushing and grinding gallium-containing solid recyclables can effectively increase the specific surface area of ​​the raw materials and promote subsequent leaching reactions.

[0024] (2) Place the ground gallium-containing solid recovery material in an acid-resistant reactor, add a 6 mol / L hydrochloric acid solution, and control the solid-liquid ratio at 1:8 (g:ml). Stir and leach at 90℃ for 4 hours. After the reaction is complete, perform solid-liquid separation (e.g., filtration) to obtain gallium-containing solids. Leachate of other metal ions.

[0025] The purpose of acid leaching is to selectively dissolve and transfer gallium elements in gallium-containing solid recoveries in ionic form to aqueous solutions, thereby achieving the initial separation of gallium from a large number of insoluble solid matrix or impurity elements, creating the necessary conditions for subsequent purification steps.

[0026] Gallium in raw materials (such as GaAs waste and GaN waste) typically exists in a solid matrix in the form of compounds (such as gallium arsenide and gallium nitride) or alloys. Acid leaching, through a chemical reaction, breaks the chemical bonds of these compounds, transforming gallium into water-soluble Ga. 3+ ion.

[0027] (3) Adjust the pH of the leachate obtained from S2 to 2.5 using sodium hydroxide solution. Add the aqueous phase and the organic phase of the composite extractant at a 1:1 ratio to a mixing and clarifying extraction tank for multi-stage countercurrent extraction. Loading The organic phase flows out from the end of the extraction section.

[0028] The composite extractant includes a main extractant and a synergistic complexing component; The main extractant is selected from at least one of phosphoric acid extractants, phosphonic acid extractants, and amine extractants; The synergistic complexing component is selected from at least one of β-diketone compounds, hydroxycarboxylic acid compounds, amino acid compounds, and nitrogen-containing heterocyclic compounds.

[0029] A preferred preparation process for a composite extractant is as follows: Di(2-ethylhexyl) phosphate (P204) was used as the main extractant, and acetylacetone (AA) was used as the synergistic complexing component. P204 and AA were placed in a beaker at a volume ratio of (14-19):(1-6), and sulfonated kerosene was added as an organic diluent to bring the total volume to the set value. Under nitrogen protection and an ice-water bath, a dehydrating condensing agent (e.g., dicyclohexylcarbodiimide) was slowly added while stirring, with a molar amount 1.05 times the total molar amount of P204 and AA. The reaction was carried out at 25°C for 12 hours. After the reaction was completed, the mixture was filtered to obtain the organic phase of the composite extractant.

[0030] It is important to note that not all organic diluents can meet the reaction requirements between the main extractant and the synergistic complexing component; they must simultaneously meet two core requirements: chemical reaction compatibility and optimized extraction performance. On the one hand, the diluent must be chemically inert and must not react with the dehydrating condensing agent (such as DCC) and the reaction components in the esterification reaction; On the other hand, it should be able to dissolve the extractant well, adjust the properties of the organic phase (such as viscosity and surface tension) to promote phase separation, and influence the form of the extractant through its polarity, thereby ensuring high capacity and high selectivity extraction of gallium ions.

[0031] Therefore, sulfonated kerosene and other aliphatic hydrocarbon diluents are generally preferred in industry because they achieve the best balance in terms of cost, stability and overall performance, while solvents containing active hydrogen or strong polarity (such as alcohols, chloroform, etc.) are usually not suitable.

[0032] (4) Prepare a hydrochloric acid solution with a concentration of 0.5 to 2.0 mol / L as a low-concentration back-extraction solution. Add the loaded organic phase obtained in S3 and the back-extraction solution to the back-extraction tank at a ratio (O / A) of 5:1 for multi-stage countercurrent back-extraction.

[0033] At this time, it is rich in high-purity Ga 3+ The aqueous phase (back-extraction solution) is collected from the end of the back-extraction section.

[0034] (5) The back-extraction solution obtained in S4 was concentrated under reduced pressure at 50°C to 85°C until crystals precipitated. The system was then cooled to room temperature, the crystals were separated by filtration, and washed with a small amount of cold ethanol. Finally, the crystals were dried in a vacuum drying oven at 80°C for 12 hours to obtain high-purity gallium precursor.

[0035] Depending on the specific requirements of the final product, the precursor can be anhydrous gallium chloride, gallium oxide, an organic gallium complex solid, or a combination thereof, and the preparation routes vary significantly: Preparation of anhydrous gallium chloride: This route is a physical crystallization process. An acidic back-extraction solution rich in gallium and chloride ions is heated and concentrated, causing the solute to become supersaturated and crystallize directly to precipitate anhydrous gallium chloride solid. Sufficient acidity must be maintained throughout the process to effectively suppress the hydrolysis of gallium ions.

[0036] Preparation of gallium oxide: This route is a chemical precipitation conversion process. First, a precipitant (such as ammonia) is added to the purified gallium-containing solution, causing gallium to precipitate out as hydroxide. Then, the precipitate is washed, dried, and calcined at high temperature in air to dehydrate and convert it into high-purity gallium oxide solid.

[0037] Preparation of gallium organic complex solids: This approach is based on coordination chemistry principles. By coordinating gallium ions with specific organic ligands (such as the co-complexing component acetylacetone), a hydrophobic neutral complex is generated, which is enriched in the organic phase. Subsequently, the organic diluent is removed by evaporation, and high-purity gallium organic complex solids can be obtained by crystallization.

[0038] In summary, the three preparation routes represent three different strategies for material purification and speciation control: physical crystallization, precipitation-thermochemical transformation, and coordination-crystallization. The preparation of anhydrous gallium chloride is the most direct and serves as an ideal raw material for subsequent chlorination reactions. The preparation of gallium oxide provides a pathway for deep purification via precipitation. The preparation of organic complex solids combines the advantages of strong coordination selectivity and ease of further purification through sublimation. The choice of specific route requires comprehensive consideration of the raw material solution composition, the requirements for removing specific impurities, and the feed adaptability to the subsequent continuous flow chlorination process.

[0039] (6) The high-purity gallium precursor obtained in step S5 (preferably anhydrous gallium chloride or its solution) is introduced into a continuous flow microreactor in the form of a solution or aerosol, while a preheated gas containing a chlorine source component (such as...) is introduced. , , (etc.) and reducing components (such as A mixed carrier gas flow of CO (or other carrier gas containing reducing components) is used. A continuous chlorination-reduction conversion reaction is carried out in a continuous flow microreactor at 200°C to 260°C and with an appropriate residence time (100 to 180 seconds).

[0040] The continuous flow microreactor is a microchannel reactor or a tubular reactor, and the material of the continuous flow microreactor is Hastelloy or quartz. And / or the fluoropolymer material lining the continuous flow microreactor.

[0041] In this invention, gallium tetrachloride ( The generation of chlorine may involve multiple parallel or competing reaction pathways, including but not limited to direct chlorination, gas-phase disproportionation reaction, coordination-assisted conversion, and mild reduction involving hydrogen. The core of this invention lies in achieving safe, controllable, and efficient operation through the efficient heat and mass transfer of a continuous flow microreactor, precise temperature and residence time control, and the coupling of a suitable chlorine source and reducing atmosphere. The specific reaction mechanism can be further studied and elucidated by those skilled in the art based on experimental conditions; this invention does not limit it in this regard.

[0042] (7) The reaction effluent first passes through a -10°C cold trap to make it gaseous. The product is condensed into a solid, while most of the byproduct gases are separated. The collected crude product is then purified by sublimation under reduced pressure at 120°C in a glove box protected by an inert gas (such as argon) (the sublimation temperature can be adjusted according to the purity of the product), ultimately yielding high-purity gallium tetrachloride in white to pale yellow crystalline form.

[0043] To fully demonstrate the inventiveness, reproducibility, and superior effects of the present invention, the following embodiments and comparative examples are provided.

[0044] Example 1: In this embodiment, a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction is as follows: (1) Take gallium arsenide wafer cutting waste, crush and grind it into 150 mesh particles for subsequent leaching.

[0045] (2) The gallium arsenide waste after grinding was leached with a hydrochloric acid solution with a concentration of 6.0 mol / L, the solid-liquid ratio was 1:8, the temperature was controlled at 90℃, and the reaction time was 4 hours to obtain gallium-containing leachate.

[0046] (3) The leachate was extracted using a composite extractant (the main extractant was a phosphonic acid extractant, and the synergistic complexing component was an amino acid compound). The extraction process was carried out using static extraction at 30°C.

[0047] (4) The organic phase was back-extracted using a 1.5 mol / L hydrochloric acid solution to obtain a high-purity back-extraction solution.

[0048] (5) The back-extraction solution was concentrated under reduced pressure at 85°C until crystals precipitated. After cooling and filtration, the solution was washed with cold ethanol and dried under vacuum at 80°C to obtain a high-purity gallium precursor.

[0049] (6) A high-purity gallium precursor solution dissolved in carbon tetrachloride is introduced into a continuous flow microreactor, while hydrogen gas that has been preheated and saturated with chlorination auxiliary components is introduced. The temperature is set to 200°C, and the residence time in the continuous flow microreactor is 120 seconds to carry out a continuous chlorination-reduction conversion reaction.

[0050] (7) The reaction effluent obtained in step (6) was condensed and collected in a -10℃ cold trap to collect the crude product. Then, it was purified by depressurization sublimation at 120℃ under argon protection to obtain high-purity gallium tetrachloride crystals.

[0051] Example 2: In this embodiment, a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction is as follows: (1) Take gallium nitride waste, crush and grind it into 150 mesh particles for subsequent leaching.

[0052] (2) The gallium nitride waste after grinding was leached with a hydrochloric acid solution with a concentration of 6.0 mol / L, the temperature was controlled at 90℃, and the reaction time was 3 hours to obtain gallium-containing leachate.

[0053] (3) The leachate was extracted using a composite extractant (the main extractant was a phosphoric acid extractant, and the synergistic complexing component was a hydroxycarboxylic acid compound). The extraction process was carried out using static extraction at 30°C.

[0054] (4) The organic phase was back-extracted using a 1.5 mol / L hydrochloric acid solution to obtain a high-purity back-extraction solution.

[0055] (5) The back-extraction solution was concentrated under reduced pressure at 85°C until crystals precipitated. After cooling and filtration, the solution was washed with cold ethanol and dried under vacuum at 80°C to obtain a high-purity gallium precursor.

[0056] (6) A high-purity gallium precursor solution dissolved in carbon tetrachloride is introduced into a continuous flow microreactor, while hydrogen gas that has been preheated and saturated with chlorination auxiliary components is introduced. The temperature is set to 220°C, and the residence time in the continuous flow microreactor is 120 seconds to carry out a continuous chlorination-reduction conversion reaction.

[0057] (7) The reaction effluent obtained in step (6) was condensed and collected in a -10℃ cold trap to collect the crude product. Then, it was purified by depressurization sublimation at 120℃ under argon protection to obtain high-purity gallium tetrachloride crystals.

[0058] Example 3: In this embodiment, a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction is as follows: (1) Take copper indium gallium selenide (CIGS) photovoltaic waste, crush and grind it into 150 mesh particles for subsequent leaching.

[0059] (2) The ground copper indium gallium selenide (CIGS) photovoltaic waste was leached with a hydrochloric acid solution with a concentration of 6.0 mol / L. The temperature was controlled at 90℃ and the reaction time was 3 hours to obtain gallium-containing leachate.

[0060] (3) The leachate was extracted using a composite extractant (the main extractant was an amine extractant, and the synergistic complexing component was a β-diketone compound). The extraction process was carried out using static extraction at 30°C.

[0061] (4) The organic phase was back-extracted with a hydrochloric acid solution with a concentration of 1.0 mol / L to obtain a high-purity back-extraction solution.

[0062] (5) The back-extraction solution was concentrated under reduced pressure at 85°C until crystals precipitated. After cooling and filtration, the solution was washed with cold ethanol and dried under vacuum at 80°C to obtain a high-purity gallium precursor.

[0063] (6) A high-purity gallium precursor solution dissolved in carbon tetrachloride is introduced into a continuous flow microreactor, while hydrogen gas that has been preheated and saturated with chlorination auxiliary components is introduced. The temperature is set to 200°C, and the residence time in the continuous flow microreactor is 150 seconds to carry out a continuous chlorination-reduction conversion reaction.

[0064] (7) The reaction effluent obtained in step (6) was condensed and collected in a -10℃ cold trap to collect the crude product. Then, it was purified by depressurization sublimation at 120℃ under argon protection to obtain high-purity gallium tetrachloride crystals.

[0065] Comparative Example 1: In this embodiment, a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction is as follows: (1) Take gallium arsenide waste, crush and grind it into 150 mesh particles for subsequent leaching.

[0066] (2) The gallium arsenide waste after grinding was leached with a hydrochloric acid solution with a concentration of 6.0 mol / L, the temperature was controlled at 90℃, and the reaction time was 3 hours to obtain gallium-containing leachate.

[0067] (3) P204 was used as the extractant to extract the leachate. The extraction process was carried out by static extraction at 30°C.

[0068] (4) The organic phase was back-extracted with a hydrochloric acid solution with a concentration of 1.0 mol / L to obtain a high-purity back-extraction solution.

[0069] (5) The back-extraction solution was concentrated under reduced pressure at 85°C until crystals precipitated. After cooling and filtration, the solution was washed with cold ethanol and dried under vacuum at 80°C to obtain a high-purity gallium precursor.

[0070] (6) A high-purity gallium precursor solution dissolved in carbon tetrachloride is introduced into a continuous flow microreactor, while hydrogen gas that has been preheated and saturated with chlorination auxiliary components is introduced. The temperature is set to 200°C, and the residence time in the continuous flow microreactor is 120 seconds to carry out a continuous chlorination-reduction conversion reaction.

[0071] (7) The crude product was collected by condensation in a -10℃ cold trap and then purified by sublimation under reduced pressure at 120℃ under argon protection to obtain gallium tetrachloride crystals.

[0072] Comparative Example 2: In this embodiment, a method for preparing high-purity gallium tetrachloride based on continuous flow microreaction is as follows: (1) Take gallium arsenide waste, crush and grind it into 150 mesh particles for subsequent leaching.

[0073] (2) The gallium arsenide waste after grinding was leached with a hydrochloric acid solution with a concentration of 6.0 mol / L, the temperature was controlled at 90℃, and the reaction time was 3 hours to obtain gallium-containing leachate.

[0074] (3) P204 was used as the extractant to extract the leachate. The extraction process was carried out by static extraction at 30°C.

[0075] (4) The organic phase was back-extracted with a hydrochloric acid solution with a concentration of 1.0 mol / L to obtain a high-purity back-extraction solution.

[0076] (5) The back-extraction solution was concentrated under reduced pressure at 85°C until crystals precipitated. After cooling and filtration, the solution was washed with cold ethanol and dried under vacuum at 80°C to obtain a high-purity gallium precursor.

[0077] (6) Mix high-purity gallium precursor with excess The liquid was added to a three-necked flask equipped with a reflux condenser and heated to 220°C in an oil bath. High-purity hydrogen gas was slowly introduced while stirring, and the reaction was allowed to proceed for 6 hours.

[0078] (7) After the reaction is complete, the mixture is cooled, the product is separated and collected by vacuum distillation, and then sublimated and purified.

[0079] The purity and related parameters of gallium tetrachloride obtained in the above examples and comparative examples are shown in Table 1 below: Table 1 Comparison of key process parameters and performance results between the examples and comparative examples. Compared with Comparative Examples 1 and 2, the technical solutions of Examples 1 to 3 have at least the following distinguishing features: First, in the gallium separation and purification stage, the examples used a composite extractant system consisting of a main extractant and a synergistic complexing component, while the comparative example used only a single P204 extractant. Secondly, in the preparation stage of gallium tetrachloride, the example uses a continuous flow microchannel reactor to complete the chlorination reduction reaction, while Comparative Example 2 uses a traditional batch reactor.

[0080] As shown in Table 1, the aforementioned distinguishing features bring about significant technical benefits: In Examples 1-3 using composite extractants, the purity of gallium tetrachloride obtained was above 99.92%, and the gallium yield was 84.8%-88.5%, which was significantly higher than that of Comparative Examples 1 and 2 using single extractants. At the same time, under continuous flow microreactor conditions, the chlorination reaction process was stable and controllable, and side reactions were significantly reduced, which further improved the product purity and yield. In contrast, under traditional batch reactor reaction conditions, the product purity and yield both decreased significantly.

[0081] Therefore, this invention, through the synergistic separation effect of the composite extractant and the organic combination of continuous flow microreactive chlorination technology, not only effectively improves the separation selectivity and recovery efficiency of gallium, but also significantly enhances the safety and controllability of the chlorination reaction, enabling the stable preparation of high-purity gallium tetrachloride under various gallium-containing solid waste conditions. Compared with the comparative example, this invention achieves significant progress in product purity, gallium yield, and process stability, demonstrating outstanding substantive features and remarkable advancements.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-purity gallium tetrachloride based on continuous flow microreaction, characterized in that, Includes the following steps; S1. Take gallium-containing solid recycled material and crush and grind it; S2. The gallium-containing solid recyclable material that has been crushed and ground is leached with an acid solution to obtain a gallium-containing leachate. S3. The leachate is extracted and purified using an organic solvent to obtain the loaded solution. An organic phase, wherein the organic phase contains a composite extractant; S4. Back-extract the load using a low-concentration acid solution. The organic phase must have high purity. The back-extraction solution; S5. Evaporate and crystallize the back-extraction solution obtained in step S4 to obtain a high-purity gallium precursor. S6. The high-purity gallium precursor is introduced into a continuous flow microreactor to carry out a chlorination reduction reaction to generate gallium tetrachloride. S7. The reaction product obtained in step S6 is separated and purified to obtain high-purity gallium tetrachloride.

2. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 1, characterized in that, In step S1, the gallium-containing solid recyclable material is selected from gallium arsenide waste, gallium nitride waste, or copper indium gallium selenide photovoltaic waste.

3. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 1, characterized in that, In step S3, the composite extractant includes a main extractant and a synergistic complexing component.

4. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 3, characterized in that: The main extractant is selected from at least one of phosphoric acid extractants, phosphonic acid extractants, and amine extractants; And / or the synergistic complexing component is selected from at least one of β-diketone compounds, hydroxycarboxylic acid compounds, amino acid compounds, and nitrogen-containing heterocyclic compounds.

5. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 3 or 4, characterized in that, The preparation method of the composite extractant is as follows: The main extractant and the synergistic complexing component are mixed in an organic diluent at a volume ratio of (14~19):(1~6), and a dehydrating condensing agent is added to carry out an esterification reaction to obtain the final product.

6. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 5, characterized in that, The dehydrating condensing agent is selected from one of dicyclohexylcarbodiimide and diisopropylcarbodiimide.

7. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 1, characterized in that, In step S5, the high-purity gallium precursor is anhydrous gallium chloride, gallium oxide, an organic complex solid of gallium, or a combination thereof.

8. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 1, characterized in that, In step S4, the low-concentration acid solution is a hydrochloric acid solution with a concentration in the range of 0.5 to 2.0 mol / L.

9. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 1, characterized in that, In step S6, the continuous flow microreactor is a microchannel reactor or a tubular reactor.

10. The method for preparing high-purity gallium tetrachloride based on continuous flow microreaction according to claim 9, characterized in that: The continuous flow microreactor is made of Hastelloy or quartz. And / or the fluoropolymer material lining the continuous flow microreactor.

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