A device and method for purifying metallic gallium by controlling a multi-temperature field

Abstract

A kind of device and method for purifying metal gallium with lower discharge multi-temperature field control, effectively solve the problems of uneven crystallization speed, unstable crystallization rate, poor product discharge and difficult industrial production application in prior art. It includes a crystallization tank, an outer temperature control box is arranged outside the crystallization tank, an inner temperature control pipe that can be vertically lifted is arranged in the crystallization tank, and the inner temperature control pipe is a rotatable structure;The lower end of the crystallization tank is provided with a lower discharger, the lower discharger penetrates the outer temperature control box, and the lower discharger includes a main pipeline, a discharge control valve is arranged on the main pipeline, and the main pipeline is coated with a discharge auxiliary heater outside.

Description

Technical Field

[0001] This invention relates to the field of gallium purification technology, and in particular to a gallium purification apparatus and method with multi-temperature field control for bottom discharge. Background Technology

[0002] Gallium is a precious rare metal widely used in semiconductor manufacturing. Gallium with a purity of 6N or higher is generally referred to as high-purity gallium, primarily used in the synthesis of gallium arsenide. Semi-insulating gallium arsenide is mainly used in 5G RF chips, microwave power amplifiers, and monolithic microwave integrated circuit devices. These chips and devices are primarily used in 5G communications, radar, high-efficiency solar cells, and high-efficiency lasers. For 7N high-purity gallium used in the molecular beam epitaxy of semi-insulating gallium arsenide, the content of major impurity elements, excluding C, N, O, and Ta, must be below 5 ppb, with some impurity element contents even below the detection limit of GDMS analysis.

[0003] Currently, the production technology for high-purity gallium is mainly controlled by companies outside mainland China, while the market for high-purity gallium is primarily monopolized by a few factories in Taiwan. Although enterprises and research institutes in mainland China have also conducted extensive research on high-purity gallium purification technologies, the dual monopoly of foreign companies over high-purity gallium production technology and the market poses a significant barrier to the development of high-purity gallium production technology in mainland China.

[0004] Crystallization is one of the main methods for purifying metallic gallium. The principle of crystallization is to partially solidify liquid metallic gallium and utilize the redistribution of impurity elements during the solidification process to obtain relatively pure solid-phase metallic gallium by distributing impurities differently in liquid and solid gallium, thus achieving the purpose of purification.

[0005] Gallium crystallization purification is a process of redistribution of impurity elements in gallium during its crystallization from liquid to solid phase. Essentially, this process involves the formation and growth of crystal nuclei. Due to the rough nucleation interface and rapid heat dissipation at the nucleation points, crystallization occurs in dendritic form. In this case, impurities remain at the final solidification points of the dendrites, hindering the removal of impurities during crystallization. The faster the crystallization rate, the more severe this phenomenon becomes, affecting crystal purity. Conversely, a slow crystallization rate results in insufficient driving force for precipitation, and even with extended crystallization time, precipitation may fail.

[0006] Meanwhile, in the process of gallium crystallization and purification, the crystallization rate affects the crystallization and purification effect. Theoretically, the less solid gallium crystals are precipitated during the crystallization and purification process, the lower the crystallization rate, and the higher the purity. However, if the crystallization rate is too low, the yield will be severely reduced, affecting the purification output and making it impossible to apply to mass production.

[0007] Because gallium has a melting point of only 29.8℃, the crystallization method for purifying gallium based on segregation theory is a simple and easy-to-implement technical route, and is widely used in the production of high-purity gallium. However, the gallium crystallization purification method also has the following problems: First, the crystallization rate is uneven and the crystallization rate is unstable, resulting in unstable quality of the purified gallium product; second, the preparation equipment has a complex structure, product discharge is not smooth, and industrial production applications are difficult. Summary of the Invention

[0008] In view of the above situation and to overcome the defects of the prior art, the present invention provides a gallium purification device and method with bottom discharge and multi-temperature field control, which effectively solves the problems of uneven crystallization rate, unstable crystallization rate, poor product discharge, and difficulty in industrial production application of the prior art.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows: a bottom discharge multi-temperature field controlled gallium metal purification device, including a crystallization tank, an external temperature control box is provided on the outside of the crystallization tank, and an internal temperature control tube that can be vertically raised and lowered is provided inside the crystallization tank. The internal temperature control tube has a rotatable structure.

[0010] The crystallizer is equipped with a lower discharge device at the lower end, which passes through the external temperature control box. The lower discharge device includes a main pipe, on which a discharge control valve is provided, and the outside of the main pipe is covered with a discharge auxiliary heater.

[0011] Preferably, it also includes a lifting device, which is connected to a lifting linkage, and the internal temperature control tube is connected to the lifting linkage.

[0012] Preferably, the upper end of the internal temperature control tube is sealed with a flange, and the flange is provided with an internal temperature water inlet pipe and an internal temperature water outlet pipe, while the external temperature control box is provided with an external temperature water inlet pipe and an external temperature water outlet pipe.

[0013] Preferably, a dust cover is also provided above the crystallization tank.

[0014] A method for purifying metallic gallium using a bottom-discharge, multi-temperature-field controlled process includes the following steps:

[0015] S1, a certain amount of liquid gallium metal raw material is added into the crystallization tank;

[0016] S2, adjust the temperature of the internal temperature control tube to between 35-40℃, the temperature of the external temperature control box to between 20-25℃, and the temperature of the discharge auxiliary heater to between 50-60℃, control the internal temperature control tube to stir up and down in the crystallization tank, after the crystallization rate reaches 90%-95%, the liquid gallium metal flows out from the lower discharge device, and the remaining solid gallium metal after crystallization and purification is melted and used as raw material for further crystallization and purification;

[0017] S3. Repeat step S2 four or more times to melt the final solid gallium metal and collect it from the bottom discharge device to obtain high-purity gallium.

[0018] Compared with existing technologies, this invention has the following advantages: This invention employs three temperature fields—an internal temperature control tube, an external temperature control box, and a discharge auxiliary heater—to achieve stable control of these three temperature fields, solving the problems of uneven crystallization rate and unstable crystallization rate in existing technologies, resulting in a product purity of 99.99999%. Simultaneously, the introduction of a bottom discharge device solves the process problem of bottom discharge in gallium crystallization purification, enabling industrial-scale intensive control from material input to product output, effectively solving difficulties in industrial production applications. The multi-temperature field control gallium purification device and method using the bottom discharge method described in this invention can effectively realize the industrial-scale mass production of high-purity gallium crystallization purification, providing strong technical support for the development of my country's high-purity gallium industry. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0020] In the diagram: 1. Internal temperature water inlet pipe; 2. Internal temperature water outlet pipe; 3. Internal temperature control pipe; 4. Dust cover; 5. Material inlet; 6. External temperature water outlet pipe; 7. External temperature control box; 8. External temperature water inlet pipe; 9. Discharge control valve; 10. Lower discharge device; 11. Direct connection; 12. Base; 13. Lifting device; 14. Lifting linkage; 15. Support frame; 16. Discharge auxiliary heater; 17. Stirring device; 18. Crystallization tank. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic diagrams, illustrating only the basic structure of the invention in a schematic manner, and therefore only show the components relevant to the invention.

[0022] Please refer to Figure 1 A bottom-discharge multi-temperature field controlled gallium metal purification device includes a crystallization tank 18, an external temperature control box 7 on the outside of the crystallization tank 18, and an internal temperature control tube 3 that can be vertically raised and lowered inside the crystallization tank 18. The internal temperature control tube 3 has a rotatable structure.

[0023] The lower end of the crystallization tank 18 is provided with a lower discharge device 10, which passes through the external temperature control box 7. The lower discharge device 10 includes a main pipe, a discharge control valve 9 is provided on the main pipe, and a discharge auxiliary heater 16 is wrapped around the outside of the main pipe.

[0024] In this device, we have a base 12, and a bracket 11 is fixed on the upper end of the base 12. The external temperature control box 7 is set above the bracket 11. The internal temperature control tube 3 is placed in the crystallization tank 18 and then placed in the external temperature control box 7. The internal temperature control tube 3, the external temperature control box 7 and the discharge auxiliary heater 16 form a three-temperature field regulation, which realizes that while the metallic gallium crystallizes in the crystallization tank 18, the metallic gallium near the bottom discharge device 10 does not crystallize.

[0025] The lower discharge device 10 is located below the crystallization tank 18 and passes through the external temperature control box 7. The crystallization tank 18, the external temperature control box 7 and the lower discharge device 10 are an integral structure.

[0026] It also includes a lifting device 13, which is connected to a lifting link 14, and the internal temperature control tube 3 is connected to the lifting link 14.

[0027] In this device, a support frame 15 is fixed to the upper end of the base 12, and a lifting device 13 is installed on the support frame 15. The lifting device 13 can be an electric push rod, a cylinder or a hydraulic cylinder, etc., so as to realize the lifting of the lifting link 14. A stirring device 17 is provided in the middle of the lifting link 14, and the stirring device 17 drives the internal temperature control tube 3 to rotate.

[0028] The upper end of the internal temperature control pipe 3 is sealed with a flange, and the flange is provided with an internal temperature water inlet pipe 1 and an internal temperature water outlet pipe 2. The external temperature control box 7 is provided with an external temperature water inlet pipe 4 and an external temperature water outlet pipe 6.

[0029] The upper end of the internal temperature control pipe 3 is sealed with a flange. An opening is made on the flange and the internal temperature water inlet pipe 1 and the internal temperature water outlet pipe 2 are welded on it, thereby realizing the water circulation for temperature control by the internal temperature control pipe 3. An opening is made on the side wall of the external temperature control box 7 and the external temperature water inlet pipe 4 and the external temperature water outlet pipe 6 are welded on it, thereby realizing the water circulation for temperature control by the external temperature control box 7.

[0030] It also includes a dust cover 4 installed above the crystallization tank 18.

[0031] A method for purifying metallic gallium using a bottom-discharge, multi-temperature-field controlled process includes the following steps:

[0032] S1, add more than 5 kg of liquid gallium metal raw material into crystallization tank 18;

[0033] S2, adjust the temperature of the internal temperature control tube 3 to between 35-40℃, the temperature of the external temperature control box 7 to between 20-25℃, and the temperature of the discharge auxiliary heater 16 to between 50-60℃, so as to ensure that when the metallic gallium crystallizes in the crystallization tank 18, the metallic gallium near the bottom discharge device 10 does not crystallize. Control the internal temperature control tube 3 to stir up and down in the crystallization tank 18. After the crystallization rate reaches 90%-95% (about 3 hours or more), the liquid metallic gallium flows out from the bottom discharge device 10. The remaining solid metallic gallium after crystallization and purification is melted and used as raw material for further crystallization and purification.

[0034] S3. Repeat step S2 more than four times, with the crystallization rate controlled at 90%-95% each time, and the crystallization speed, expressed as crystallization time, controlled at more than 3 hours. After melting the final solid gallium metal, collect it from the lower discharge device 10 to obtain high-purity gallium with a purity of 99.999999%.

[0035] The temperature of the lower discharge device 10 is maintained between 50-60℃. The material inlet 5 of multiple purification devices and the outlet of the lower discharge device 10 are connected in parallel to the corresponding main pipeline, which can realize the production line production of multiple purification devices in parallel and realize the industrialized and intensive control of high-purity gallium purification.

[0036] After melting gallium raw material (99.99%), it is poured into crystallization tank 18. The external temperature control, internal temperature control, and discharge auxiliary heater 16 are adjusted. The speed of the internal temperature control moving up and down is adjusted. After crystallization is completed, the liquid phase gallium is discharged from the lower discharge device 10 and the discharge control valve 9 is closed. The solid gallium in crystallization tank 18 is used as raw material to continue the purification of the next crystallization cycle. The above steps are repeated 4 times to obtain high-purity gallium. The product quality reaches 99.99999% after GDMS testing. The test results meet the requirements of GB / T10118 high-purity gallium product standard 7N product grade, as shown in Table 1.

[0037] Table 1: Product Quality

[0038]

[0039]

[0040] The embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that various variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom remain within the scope of this invention.

Claims

1. A bottom-discharge multi-temperature field controlled gallium metal purification device, characterized in that, It includes a crystallization tank, an external temperature control box on the outside of the crystallization tank, and an internal temperature control tube that can be raised and lowered vertically inside the crystallization tank. The internal temperature control tube has a rotatable structure. The crystallizer is equipped with a lower discharge device at the lower end, which passes through the external temperature control box; The discharge device includes a main pipe, on which a discharge control valve is installed; The main pipeline is externally covered with a discharge auxiliary heater; Also includes: lifting equipment; The lifting equipment is connected to a lifting linkage, and the internal temperature control tube is connected to the lifting linkage. A stirring device is installed in the middle of the lifting linkage, which drives the internal temperature control tube to rotate.

2. The gallium purification device with bottom discharge and multi-temperature field control according to claim 1, characterized in that, The upper end of the internal temperature control tube is sealed with a flange, and the flange is provided with an internal temperature inlet pipe and an internal temperature outlet pipe. The external temperature control box is provided with an external temperature inlet pipe and an external temperature outlet pipe.

3. The gallium purification device with bottom discharge and multi-temperature field control according to claim 1, characterized in that, It also includes a dust cover installed above the crystallization tank.

4. A method for purifying metallic gallium using any one of the purification apparatuses of claims 1 to 3, comprising the following steps: S1, a certain amount of liquid gallium metal raw material is added into the crystallization tank; S2, adjust the temperature of the internal temperature control tube to between 35 and 40°C, the temperature of the external temperature control box to between 20 and 25°C, and the temperature of the discharge auxiliary heater to between 50 and 60°C; The internal temperature control tube is used to stir the crystallizer up and down. Once the crystallization rate reaches 90%-95%, the liquid gallium metal flows out from the lower discharge device; The remaining solid gallium metal after crystallization and purification is melted and used as a raw material for further crystallization and purification. S3. Repeat step S2 four or more times to melt the final solid gallium metal and collect it from the bottom discharge device to obtain high-purity gallium.

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