CN111363933A

CN111363933A - Production equipment and method of high-purity gallium

Info

Publication number: CN111363933A
Application number: CN202010180668.4A
Authority: CN
Inventors: 王友彬; 洪标; 韦悦周; 袁增崟; 林学亮; 邹睿
Original assignee: Guangxi University
Current assignee: Guangxi University
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-07-03
Anticipated expiration: 2040-03-16
Also published as: CN111363933B

Abstract

The invention provides production equipment and a method of high-purity gallium. The method comprises the following steps: and introducing circulating hot water into the medium circulating tank, placing the processed liquid crude gallium into the crystallizing tank through an inlet of the crystallizing tank, introducing circulating cold water into the first medium circulating tank, placing crystal seeds through the inlet of the crystallizing tank after the critical crystallization temperature is reached, introducing circulating cold water into the next medium circulating tank after each crystallization period, introducing circulating cold water into the last but one medium circulating tank until the last medium circulating tank is filled with the circulating cold water, discharging residual gallium liquid through a liquid gallium discharging device after full crystallization, and repeatedly crystallizing for 5-7 times, wherein the purity of the final product can reach 6-7N. The equipment has the advantages of simple structure, easy operation, environmental protection, energy conservation, effective shortening of the production period, saving of the production cost and improvement of the production efficiency.

Description

Production equipment and method of high-purity gallium

Technical Field

The invention relates to the field of high-purity gallium preparation, in particular to production equipment and a method for high-purity gallium.

Background

High purity gallium is a key base material for the preparation of semiconductor compounds. These semiconductor compounds are widely used in the semiconductor industry, the photovoltaic industry, and the like. China is the largest gallium producing country in the world, and supplies more than 70% of the global demand. The crude gallium has high impurity content, so the application is limited and the additional value is low. In order to improve the added value of gallium and expand the application range of gallium, crude gallium is industrially utilized as a raw material, and high-purity gallium (more than 6N) is prepared by different purification methods. At present, the technology for preparing high-purity gallium can be mainly divided into two main categories: indirect purification methods and direct purification methods.

The indirect purification method is usually gallium trichloride purification method (patent application CN104018012A) and organic compound thermal decomposition method (patent CN103114214A), and the indirect purification method has the problems of complex operation process, difficult control, easy limitation on the purity of reagents, toxic by-products in the production process, environment friendliness and the like.

Compared with the indirect purification method, the direct purification method has the advantages of simple process and high efficiency, and is most commonly used in industrial production. Among them, the vacuum distillation method (patent CN206783742U) utilizes the high boiling point (2400 ℃) characteristic of gallium metal, and can better remove volatile impurities, but the equipment energy consumption is high, and is generally used for treating gallium-containing waste and defective gallium. The electrolytic refining method (patent CN16190818A and patent CN 107338455A) is a relatively common method for purifying primary gallium. Generally, 2N metal gallium can obtain 5N-6N high-purity gallium through twice electrolytic refining, but is limited by the defects of the electrolytic refining method, and impurities (such as Zn and Si) which are close to the reduction potential of the gallium are difficult to separate. The crystallization method utilizes the different distribution of impurity elements in different metal condensed solid states and molten states to redistribute the impurity elements in the liquid gallium and the solid gallium so as to achieve the purpose of purifying the metal gallium. The method has simple requirements on equipment, simple and convenient operation process and short production period, and is beneficial to realizing the industrial production of the ultra-high purity gallium.

The techniques and inventions disclosed so far provide a number of crystallization methods for preparing high purity gallium, but the existing crystallization methods have some disadvantages: 1. after each crystallization, the liquid gallium on the surface is sucked out by a suction pipe or poured out by some means, which is not beneficial to simplify the operation process, for example, patent CN 106636682B. 2. The seed crystal placing process is complicated, and some methods even need to pour out gallium liquid during secondary seed crystal adding, which is inconvenient for continuous production, such as patent CN104878224B and patent application CN 101082086A. 3. The solidification rate of each crystallization cannot be effectively controlled, and only can be realized by observing or estimating the crystallization time to discharge residual gallium in time, which is not beneficial to industrial production, for example, patent CN 106048262A. 4. The heat exchange between the medium and the gallium liquid is not good enough, so that the crystal is not oriented, and impurities in the gallium liquid are difficult to form better aggregates, for example, patent CN 104878224B.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides production equipment and a method for high-purity gallium.

The implementation mode of the invention is as follows: the production equipment of high-purity gallium is characterized by comprising a crystallization tank, a medium circulation tank, a heat insulation layer and a liquid gallium discharge device; a crystallization tank inlet is arranged at the left upper part of the crystallization tank, and a crystallization tank outlet is arranged at the right upper part of the crystallization tank; the medium circulation grooves comprise n independent medium circulation grooves, wherein n is an integer and is more than or equal to 5 and less than or equal to 10; each medium circulation groove consists of a circulation main body, a medium inlet and a medium outlet, the n medium circulation grooves are sequentially distributed along the crystallization groove from left to right in a transverse mode, each medium circulation groove circulation main body is located inside the crystallization groove, and the medium inlet and the medium outlet penetrate through the crystallization groove and extend to the outside of the crystallization groove; the heat insulation layer is distributed around the crystallization tank; the liquid gallium discharging device comprises a gallium discharging tube and a gallium discharging switch, the gallium discharging tube is arranged at the right lower part of the crystallization tank, and the gallium discharging switch is arranged on the gallium discharging tube. In the invention, the crystallization tank is transversely arranged, liquid crude gallium is added through the inlet of the crystallization tank, and the gallium is crystallized and melted by introducing cold and hot media into the medium circulation tank. The inlet of the crystallizing tank can also be used for placing seed crystals, and the added seed crystals are positioned at the first medium circulating tank because the inlet of the crystallizing tank is positioned at the left side of the first medium circulating tank. When the gallium liquid is solidified, nucleation is performed from the first medium circulation tank, the design of the n medium circulation tanks is matched, so that the gallium liquid is directionally solidified, impurities in the gallium liquid are gradually enriched from a solid phase to a liquid phase, namely, the impurities are gradually accumulated from the left side of the crystallization tank to the right side of the crystallization tank, and then the impurities are removed. And discharging residual gallium liquid after each crystallization through a liquid gallium discharging device and collecting finished high-purity gallium. The heat insulation layer arranged outside the crystallization tank is more favorable for improving the heat exchange efficiency.

Preferably, the circulation body of the medium circulation tank is one of a circular ring shape and a row shape.

Preferably, the shape of the crystallization tank is one of a cylindrical barrel body or a rectangular parallelepiped.

A production method of high-purity gallium comprises the following steps: step one, closing a gallium discharging switch, adding liquid crude gallium into a crystallization tank through an inlet of the crystallization tank, and introducing a heat medium into all medium circulation tanks to enable the crude gallium to be in a liquid state; step two, introducing a cold medium into the first medium circulating tank until the gallium liquid reaches the critical crystallization temperature; placing seed crystals into the gallium liquid through an inlet of the crystallization tank, and then introducing protective gas through the inlet of the crystallization tank; step four, after waiting for a proper amount of crystallization time, introducing a cold medium into the next medium circulation tank, waiting for a period of crystallization time until the cold medium is introduced into the n-1 th medium circulation tank, stopping introducing protective gas after sufficient crystallization, opening a gallium discharge switch, discharging residual gallium liquid in the crystallization tank, and closing the gallium discharge switch; introducing a heat medium into all medium circulating grooves until the gallium crystallized in the previous step is completely melted; step six, repeating the step two to the step five for 4-6 times, so that the gallium in the crystallization tank is repeatedly crystallized for 4-6 times; and seventhly, opening a gallium discharge switch, and collecting the gallium liquid obtained finally after flowing out from the gallium discharge pipe to obtain the high-purity gallium. According to the method, through placing seed crystals at an inlet of a crystallization tank and introducing protective gas, directional solidification of gallium liquid from left to right is formed through the design of N medium circulation tanks, and high-purity gallium with the purity of 6N-7N is obtained through 5-7 times of crystallization; because the heat medium is always introduced into the nth medium circulating groove during each crystallization, the gallium liquid at the rightmost side of the nth medium circulating groove is never crystallized, and the control of the solidification rate and the crystallization time can be realized by adjusting the temperature of the nth medium circulating groove.

Preferably, the cold medium and the hot medium are one of water, ethylene glycol or a mixture of water and ethylene glycol.

Preferably, the temperature of the cold medium is 2-25 ℃.

Preferably, the temperature of the heat medium is 35-80 ℃.

Preferably, the protective gas is one of high-purity nitrogen or high-purity argon.

The invention utilizes the different distribution of impurity elements in different phases to redistribute impurities in liquid gallium and solid gallium to obtain purer metal gallium, thus achieving the purpose of purification, and the purification from metal crude gallium (4N) to high purity gallium (6N-7N) can be realized by adopting the equipment and the method of the invention. The medium circulation tank can be provided with a plurality of stages of medium circulation tanks according to actual requirements. The beneficial effects include: (1) the device has simple structure and convenient installation and use, places the seed crystal through the inlet of the crystallization tank, discharges residual gallium liquid crystallized each time and collects high-purity gallium of a final product through the liquid gallium discharge device, and simplifies the operation difficulty. (2) According to the invention, through the design of the inlet structure of the crystallization tank and the medium circulation tank, the gallium liquid forms transverse directional solidification, and the crystallization time and the crystallization solidification rate of each time can be controlled by controlling the temperature of the medium introduced into the nth medium circulation tank, so that the production operation is simplified. (3) The invention improves the heat exchange efficiency through the built-in medium circulation tank and the external heat insulation layer, and saves more energy. (4) In the invention, the medium inlet and the medium outlet of each independent medium circulation groove penetrate through the crystallization groove and extend to the outside of the crystallization groove, and except the circulation main body, other parts are beneficial to improving the crystallization of the gallium liquid when being introduced with cold medium. (5) The method for preparing high-purity gallium has the advantages of short production period, high purity of the obtained high-purity gallium, high yield and good application prospect.

Drawings

FIG. 1 is a schematic diagram of an apparatus for producing high purity gallium containing ten-stage medium circulation tanks according to the present invention.

FIG. 2 is a structural diagram of a high purity gallium preparation apparatus comprising a seven-stage medium circulation tank according to the present invention.

FIG. 3 is a front view of the apparatus for preparing high purity gallium containing five stages of medium circulation tanks according to the present invention.

FIG. 4 is a left side view of a row-shaped circulating main body in the structure of the high-purity gallium preparation device containing the five-stage medium circulating tank in FIG. 3.

Wherein, 1, a crystallization tank; 201. a first medium circulation tank; 202. a second medium circulation tank; 203. a third medium circulation tank; 204. a fourth medium circulation tank; 205. a fifth medium circulation tank; 206. a sixth medium circulation tank; 207. a seventh medium circulation tank; 208. an eighth medium circulation tank; 209. a ninth medium circulation tank; 210. a tenth medium circulation tank; 3. an inlet of a crystallization tank; 4. an outlet of the crystallization tank; 5. a gallium discharge tube; 6. a gallium-discharging switch; 7. an insulating layer.

Detailed Description

Detailed description of the preferred embodimentsthe following detailed description of the present invention will be given with reference to the accompanying drawings 1-4, but it should be understood that the scope of the present invention is not limited to the specific embodiments. The purity analysis method of gallium in the embodiment of the invention is a Glow Discharge Mass Spectrometry (GDMS) method, and detection is carried out by Evens material science and technology (Shanghai) Co., Ltd. Table 1 shows the impurity content of crude gallium In examples 1 to 4 of the present invention, and the impurity elements with higher detection limit In crude gallium are In, Ni, Cu, Zn, Hg and Pb, and the total content is 0.001232%.

Table 1, examples 1 to 4 show the content of impurities in crude gallium

Example 1:

a production facility of high-purity gallium is shown in figure 1 and comprises a crystallization tank 1, a medium circulation tank, a heat insulation layer 7 and a liquid gallium discharge device; a crystallization tank inlet 3 is arranged at the left upper part of the crystallization tank 1, and a crystallization tank outlet 4 is arranged at the right upper part of the crystallization tank; the medium circulation grooves comprise n independent medium circulation grooves, wherein n is an integer and is more than or equal to 5 and less than or equal to 10; each medium circulation groove consists of a circulation main body, a medium inlet and a medium outlet, the n medium circulation grooves are sequentially distributed along the crystallization groove 1 from left to right in a transverse mode, the circulation main body of each medium circulation groove is positioned inside the crystallization groove 1, and the medium inlet and the medium outlet penetrate through the crystallization groove 1 and extend to the outside of the crystallization groove 1; the heat insulation layer 7 is distributed around the crystallization tank 1; the liquid gallium discharging device comprises a gallium discharging tube 5 and a gallium discharging switch 6, wherein the gallium discharging tube 5 is arranged at the lower right of the crystallization tank 1, and the gallium discharging switch 6 is arranged on the gallium discharging tube 5.

The method for producing high-purity gallium by using the device comprises the following steps: step one, closing a gallium discharging switch 6, adding liquid crude gallium into a crystallization tank 1 through a crystallization tank inlet 3, and introducing a heat medium into all medium circulation tanks to enable the crude gallium to be in a liquid state; step two, introducing a cold medium into the first medium circulating tank 201 until the gallium liquid reaches the critical crystallization temperature; placing seed crystals into the gallium liquid through an inlet 3 of the crystallization tank, and then introducing protective gas through the inlet 3 of the crystallization tank; step four, after waiting for a proper amount of crystallization time, introducing a cold medium into the next medium circulation tank, waiting for a period of crystallization time until introducing the cold medium into the n-1 medium circulation tank, stopping introducing protective gas after sufficient crystallization, opening a gallium discharge switch 6, discharging residual gallium liquid in the crystallization tank 1, and closing the gallium discharge switch 6; introducing a heat medium into all medium circulating grooves until the gallium crystallized in the previous step is completely melted; step six, repeating the step two to the step five for 4 times, so that the gallium in the crystallization tank 1 is repeatedly crystallized for 4 times; and seventhly, opening the gallium discharging switch 6, and collecting the gallium liquid obtained finally flowing out of the gallium discharging pipe 5 to obtain the high-purity gallium.

In the structure of the device of the embodiment: (1) n is 10; (2) the crystallization tank 1 is a cylindrical barrel, and the crystallization tank 1 is transversely arranged; (3) the circulating body of each medium circulating groove is in a circular ring shape.

In the production steps of this example: (1) the cold medium and the heat medium are both water; (2) the flow rate of the cold medium is 10L/h, and the temperature is 10 ℃; (3) the heat medium flow of the first medium circulation groove 201 to the ninth medium circulation groove 209 is 10L/h, and the heat medium temperature is 40 ℃; (4) the flow of a heat medium introduced into the tenth medium circulation groove is 10L/h, and the temperature of the heat medium is 65 ℃; (5) the protective gas is high-purity nitrogen.

Table 2 shows the content of impurities in the high-purity gallium obtained in this example. The impurity elements with high detection limit in the high-purity gallium prepared by the method of the invention comprise Cu, Hg and Pb, and the total amount of the impurity elements is 0.000052%. As can be seen from the comparison of the data in tables 1 and 2, the purity of gallium metal was purified from 99.998768% (4N grade) to 99.999948% (6N) after five crystallization processes using the apparatus and method of the present invention. The purity of the high purity gallium prepared in example 1 was 6N, and the yield was 77%.

Table 2, high purity gallium impurity content table prepared in example 1

Example 2:

as shown in fig. 2, the apparatus of the present embodiment is different from embodiment 1 in that: (1) n is 7.

Compared with the production steps of the embodiment 1, the production steps of the embodiment are different in that: (1) the cold medium and the heat medium are both ethylene glycol; (2) the flow rate of a cold medium is 10L/h, and the temperature of the medium is 2 ℃; (3) the heat medium flow of the first medium circulation groove 201 to the sixth medium circulation groove 206 is 10L/h, and the medium temperature is 35 ℃; (4) the flow rate of the heat medium introduced into the seventh medium circulation groove 207 is 10L/h, and the medium temperature is 70 ℃; (5) and step six, repeating the step two to the step five for 5 times, so that the gallium in the crystallization tank 1 is repeatedly crystallized for 5 times.

Table 3 shows the content of high purity gallium impurity prepared in this example. The impurity elements with high detection limit in the high-purity gallium prepared by the method of the invention comprise Cu and Pb, and the total amount of the impurity elements is 0.0000025%. As can be seen from a comparison of the data in tables 1 and 3, the purity of gallium metal was purified from 99.998768% (grade 4N) to 99.9999975% (7N) after six crystallization processes using the apparatus and method of the present invention. The purity of the high-purity gallium obtained in example 2 was 7N, and the yield was 74%.

Table 3, high purity gallium impurity content table prepared in example 2

Example 3:

as shown in fig. 3 to 4, the apparatus of the present embodiment is different from that of embodiment 1 in that: (1) n is 5; (2) the crystallization tank 1 is cuboid, and (3) the circulation main body of each medium circulation tank is in a row shape.

Compared with the production steps of the embodiment 1, the production steps of the embodiment are different in that: (1) the cold medium and the heat medium are both ethylene glycol; (2) the flow rate of a cold medium is 10L/h, and the temperature of the medium is 25 ℃; (3) the heat medium flow of the first medium circulation groove 201 to the fourth medium circulation groove 204 is 10L/h, and the medium temperature is 80 ℃; (4) the flow rate of the heat medium introduced into the fifth medium circulation groove 205 is 10L/h, and the medium temperature is 80 ℃; (5) step six, repeating the step two to the step five for 6 times, so that the gallium in the crystallization tank 1 is repeatedly crystallized for 6 times; (6) the protective gas is high-purity argon.

Table 4 shows the impurity content of high purity gallium prepared in example 3. The impurity elements with high detection limit in the high-purity gallium prepared by the method of the invention comprise Cu, Pb and Hg, and the total amount of the impurity elements is 0.0000014%. As can be seen from comparison of the data in tables 1 and 4, the purity of gallium metal was purified from 99.998768% (grade 4N) to 99.9999986% (7N) after seven crystallization processes using the apparatus and method of the present invention. The purity of the high-purity gallium obtained in example 3 was 7N, and the yield was 70%.

Table 4, high purity gallium impurity content table prepared in example 3

Claims

1. The production equipment of high-purity gallium is characterized by comprising a crystallization tank, a medium circulation tank, a heat insulation layer and a liquid gallium discharge device; a crystallization tank inlet is arranged at the left upper part of the crystallization tank, and a crystallization tank outlet is arranged at the right upper part of the crystallization tank; the medium circulation grooves comprise n independent medium circulation grooves, wherein n is an integer and is more than or equal to 5 and less than or equal to 10; each medium circulation groove consists of a circulation main body, a medium inlet and a medium outlet, the n medium circulation grooves are sequentially distributed along the crystallization groove from left to right in a transverse mode, each medium circulation groove circulation main body is located inside the crystallization groove, and the medium inlet and the medium outlet penetrate through the crystallization groove and the heat insulation layer and extend to the outside of the crystallization groove; the heat insulation layer is distributed around the crystallization tank; the liquid gallium discharging device comprises a gallium discharging tube and a gallium discharging switch, the gallium discharging tube is arranged at the right lower part of the crystallization tank, and the gallium discharging switch is arranged on the gallium discharging tube.

2. The apparatus for producing high purity gallium according to claim 1, wherein the circulation body of each medium circulation tank is one of a ring shape and a row shape.

3. The apparatus for producing high purity gallium according to claim 1, wherein said crystallization vessel is in the shape of one of a cylindrical barrel or a rectangular parallelepiped.

4. A method for producing high purity gallium using the production facility for high purity gallium as claimed in any one of claims 1 to 3, characterized by comprising the steps of: step one, closing a gallium discharging switch, adding liquid crude gallium into a crystallization tank through an inlet of the crystallization tank, and introducing a heat medium into all medium circulation tanks to enable the crude gallium to be in a liquid state; step two, introducing a cold medium into the first medium circulating tank until the gallium liquid reaches the critical crystallization temperature; placing seed crystals into the gallium liquid through an inlet of the crystallization tank, and then introducing protective gas through the inlet of the crystallization tank; and step four, after waiting for a proper amount of crystallization time, introducing a cold medium into the next medium circulation tank until the cold medium is introduced into the n-1 medium circulation tank, and waiting for a period of crystallization time. After full crystallization, stopping introducing the protective gas, opening a gallium discharge switch, discharging residual gallium liquid in the crystallization tank, and closing the gallium discharge switch; introducing a heat medium into all medium circulating grooves until the gallium crystallized in the previous step is completely melted; step six, repeating the step two to the step five for 4-6 times, so that the gallium in the crystallization tank is repeatedly crystallized for 4-6 times; and seventhly, opening a gallium discharge switch, and collecting the gallium liquid obtained finally after flowing out from the gallium discharge pipe to obtain the high-purity gallium.

5. The method for producing high purity gallium according to claim 4, wherein the cold medium and the hot medium are one of water, ethylene glycol or a mixture thereof.

6. The method for producing high purity gallium according to claim 4, wherein the shielding gas is one of high purity nitrogen or high purity argon.

7. The method for producing high-purity gallium according to claim 4, wherein the temperature of the cooling medium is 2 to 25 ℃.

8. The method for producing high-purity gallium according to claim 4, wherein the temperature of the heat medium is 35 to 80 ℃.