阅读说明：本技术 一种电子级高纯铝晶析方法 (Electronic grade high-purity aluminum crystallization method ) 是由 张瑾 张飞 周诗怀 叶翔 周建波 于 2020-12-04 设计创作，主要内容包括：本发明公开了一种电子级超高纯铝晶析方法,选取纯度为4N5及以上的高纯铝原料在坩埚中融化成铝液,将晶析装置插入坩埚,使石墨管套伸入铝液深度300~600mm；启动驱动装置,驱动石墨管套同步旋转,然后向转体内通入冷却气体开始晶析,晶析过程中保持晶析机转速匀速性和冷却气体稳定性,使与铝液接触的石墨管套表面定向凝固和析出一定厚度的倒蘑菇型晶析物；当达到晶析设定时间,首先停止晶析装置旋转,然后关闭晶析装置气冷系统通气阀,从石墨坩埚中抬出晶析装置,摘下晶析机下方石墨管套上的结晶物,将晶析物头部切除40~60mm,得到高纯晶析物,倒出埚中中剩余铝液,将高纯晶析物再次放入坩埚中重复晶析可得到纯度更高的晶析物。(The invention discloses an electronic grade ultra-high purity aluminum crystallization method, which comprises the steps of selecting high purity aluminum raw materials with the purity of 4N5 and above to be melted into aluminum liquid in a crucible, inserting a crystallization device into the crucible, and enabling a graphite pipe sleeve to extend into the aluminum liquid to a depth of 300-600 mm; starting a driving device to drive the graphite pipe sleeve to synchronously rotate, then introducing cooling gas into the rotating body to start crystallization, and keeping the rotating speed of a crystallization machine and the stability of the cooling gas in the crystallization process to directionally solidify and separate out inverted mushroom-shaped crystallized substances with certain thickness on the surface of the graphite pipe sleeve contacted with the aluminum liquid; when the set crystallization time is up, firstly stopping the rotation of the crystallization device, then closing a vent valve of an air cooling system of the crystallization device, lifting the crystallization device out of a graphite crucible, removing crystals on a graphite pipe sleeve below the crystallization machine, cutting off the head of the crystals by 40-60 mm to obtain high-purity crystals, pouring out the residual aluminum liquid in the crucible, and putting the high-purity crystals into the crucible again to repeat crystallization to obtain the crystals with higher purity.)

1. An electronic grade ultra-high purity aluminum crystallization method is characterized in that: the method comprises the following steps:

1) putting a high-purity aluminum raw material with the purity of 4N5 or more into a crucible (3) to be melted into aluminum liquid, and setting the melting temperature to be 670-720 ℃;

2) fixedly installing a crystallization device above the crucible (3), keeping a graphite pipe sleeve (7) at the lower end of the rotating body concentric with the crucible (3) and extending below the liquid level (4) of the aluminum liquid;

3) starting a driving device (2) to drive the rotating body to drive the graphite pipe sleeve (7) to rotate at a rotating speed of 90-120 rpm;

4) introducing cooling gas into a cooling gas path (5) in the rotator to start crystallization, and in the crystallization process, keeping the rotator to rotate at a constant speed and continuously introducing the cooling gas into the cooling gas path (5) to ensure that the outer surface of the graphite pipe sleeve (7) in contact with the molten aluminum is directionally solidified to form a crystallized product with a certain thickness;

5) when the set crystallization time is reached, closing the driving device (2), stopping introducing cooling gas into the cooling gas path (5), lifting out the crystallization device, removing crystals, and cutting off the heads of the crystals by 40-60 mm to obtain high-purity crystals;

6) pouring out the residual aluminum liquid in the crucible (3), and putting the high-purity crystallized product into the crucible (3) again to repeat the steps 1) -5) to obtain the ultrahigh-purity crystallized product.

2. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: and (3) after the crystallization device in the step 2) is arranged above the crucible (3), filling protective gas into the gas protection cavity (31) through the protective gas circuit (6).

3. The method for crystallization of high-purity aluminum of electronic grade according to claim 2, characterized in that: the pipe diameter of the protective gas circuit (6) is 3mm, the pressure of the introduced argon is 0.15-0.3 MPa, and the ventilation time is 100 min.

4. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: after the crystallization device in the step 2) is arranged above the crucible (3), the gas charging device (63) is started to charge protective gas into the cooling gas path (5), so that the protective gas is taken as cooling gas to cool the rotating body, discharged through the gas outlet (54) and charged into the gas protection cavity (31) to play the role of the protective gas again.

5. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: the crystallization device in the step 2) needs to be preheated before being arranged above the crucible (3), the preheating temperature is 500-700 ℃, and the preheating time is 20-60 min.

6. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: the graphite pipe sleeve (7) in the step 2) extends 300-600 mm below the liquid level (4) of the aluminum liquid.

7. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: and in the step 4), normal-temperature compressed air of 200-800L/min is introduced into a cooling air path (5) in the rotor, the normal-temperature compressed air is introduced for 10min at 200L/min, then the normal-temperature compressed air is introduced for 90min at 700L/min, and the compressed air is exhausted to the air through an air outlet (54) of a cooling air path positioned outside the crucible (3).

8. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: the crystallization time in the step 4) is 90-120 min.

9. The method for crystallization of high-purity aluminum of electronic grade according to claim 1, characterized in that: and 5) after the crystallization device is taken out, cooling the high-purity crystal outside the graphite pipe sleeve (7) in the air, cooling to 200-250 ℃, and then heating the high-purity crystal at 600-650 ℃ until the high-purity crystal automatically falls off from the graphite pipe sleeve (7).

Technical Field

The invention relates to a purification technology of metal aluminum, in particular to an electronic grade high-purity aluminum crystallization method.

Background

The aluminum product with the purity of more than 5N5 is called ultra-high purity aluminum, and the ultra-high purity aluminum is widely applied in the fields of electronics, aviation, navigation, chemical industry, national defense industry and the like, and the dosage is increased year by year. However, at present, few enterprises can produce 5N5 ultra-high purity aluminum meeting the requirements of users domestically, and research and development units have a reasonable number, so that the ultra-high purity aluminum required domestically almost depends on import.

In the prior art, as proposed in the patent application with application number 201610042682.1, an ultra-high purity aluminum purification method comprises selecting refined aluminum with a purity of at least 4N 6; the inner wall of the crucible is coated with an anti-oxidation layer; the seed crystal adopts 5N aluminum as a material; keeping the temperature of the aluminum liquid at 680-700 ℃; the seed crystal extends into the liquid level for 2-3 cm, and the final crystal is in an inverted mushroom shape; the seed crystal rotating speed is 60-100 rpm, and the aluminum liquid is driven to rotate spirally; the cooling air rate is 1-3L/min, and the temperature is 0-20 ℃; the example produces 200-300 kg of ultra-high purity aluminum. The method has a plurality of defects, such as: the seed crystal is made of 5N as a raw material, so that the seed crystal is high in manufacturing cost, not suitable for processing and poor in cooling effect; the seed crystal drives the aluminum liquid to spirally rotate, so that the aluminum liquid is easily contacted and mixed with air to influence purification, and therefore, how to reduce the purification cost and quickly purify the ultrahigh-purity aluminum is an urgent problem to be solved.

Disclosure of Invention

The invention aims to solve the technical problem of providing an electronic grade high-purity aluminum crystallization method, which solves the problems of high purification cost and poor purification effect in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an electronic grade ultra-high purity aluminum crystallization method is characterized in that: the method comprises the following steps:

1) putting a high-purity aluminum raw material with the purity of 4N5 or more into a crucible (3) to be melted into aluminum liquid, and setting the melting temperature to be 670-720 ℃;

2) fixedly installing a crystallization device above the crucible (3), keeping a graphite pipe sleeve (7) at the lower end of the rotating body concentric with the crucible (3) and extending below the liquid level (4) of the aluminum liquid;

3) starting a driving device (2) to drive the rotating body to drive the graphite pipe sleeve (7) to rotate at a rotating speed of 90-120 rpm;

4) introducing cooling gas into a cooling gas path (5) in the rotator to start crystallization, and in the crystallization process, keeping the rotator to rotate at a constant speed and continuously introducing the cooling gas into the cooling gas path (5) to ensure that the outer surface of the graphite pipe sleeve (7) in contact with the molten aluminum is directionally solidified to form a crystallized product with a certain thickness;

5) when the set crystallization time is reached, closing the driving device (2), stopping introducing cooling gas into the cooling gas path (5), lifting out the crystallization device, removing crystals, and cutting off the heads of the crystals by 40-60 mm to obtain high-purity crystals;

6) pouring out the residual aluminum liquid in the crucible (3), and putting the high-purity crystallized product into the crucible (3) again to repeat the steps 1) -5) to obtain the ultrahigh-purity crystallized product.

Preferably, the crystallization device in the step 2) is installed above the crucible 3, and then a shielding gas is charged into the gas shield chamber 31 through the shielding gas passage 6.

Preferably, the diameter of the protective gas circuit (6) is 3mm, the pressure of the introduced argon is 0.15-0.3 MPa, and the ventilation time is 100 min.

Preferably, after the crystallization device in the step 2) is installed above the crucible (3), the gas charging device (63) is started to charge the protective gas into the cooling gas path (5), so that the protective gas is taken as the cooling gas to cool the rotating body, is discharged through the gas outlet (54), and is charged into the gas protection cavity (31) to play the role of the protective gas again.

Preferably, the crystallization device in the step 2) needs to be preheated before being arranged above the crucible (3), wherein the preheating temperature is 500-700 ℃, and the preheating time is 20-60 min.

Preferably, the graphite pipe sleeve (7) in the step 2) extends 300-600 mm below the liquid level (4) of the aluminum liquid.

Preferably, in the step 4), normal-temperature compressed air of 200-800L/min is introduced into the cooling air path (5) in the rotor, the normal-temperature compressed air is introduced for 10min at 200L/min, then the normal-temperature compressed air is introduced for 90min at 700L/min, and the compressed air is exhausted to the air through an air outlet (54) of the cooling air path, which is positioned outside the crucible (3).

Preferably, the crystallization time in the step 4) is 90 to 120 min.

Preferably, after the crystallization device is taken out in the step 5), the graphite pipe sleeve (7) and the high-purity crystal outside the graphite pipe sleeve (7) are cooled in the air, the temperature is reduced to 200-250 ℃, and then the high-purity crystal is heated at 600-650 ℃ until the high-purity crystal automatically falls off from the graphite pipe sleeve (7).

Compared with the prior art, the electronic grade high-purity aluminum crystallization method has the advantages that,

(1) the cooling gas circuit is arranged in the rotating body to cool the rotating body, and high-purity aluminum crystals can be formed on the rotating body through solidification and accumulation by matching with the rotation of the rotating body, so that the purification of the aluminum liquid is realized; the graphite pipe sleeve made of graphite material is sleeved at the lower end of the rotating body, due to the excellent heat transfer effect of the graphite material, when the rotating body is cooled, the low temperature of cooling gas can be rapidly transferred to cool the graphite pipe sleeve, so that high-purity aluminum crystals are solidified and accumulated on the outer side of the graphite pipe sleeve, the crystallization effect is good, after the crystallization is completed, the rotating body with the high-purity aluminum crystals is taken out from the crucible and is naturally cooled, then the graphite pipe sleeve and the aluminum crystals are heated at the same time, and the aluminum crystals can rapidly expand due to heating and naturally fall off from the outer side of the graphite pipe sleeve, so that the high-purity aluminum crystals can be more easily obtained by the method compared with the prior art;

(2) according to the purity and the volume of the required high-purity crystal, cooling gas circuits in different shapes are arranged in the rotating body, and the cooling gas is filled at the flow rate, so that the rotating body can be cooled quickly or slowly, and the cooling rate during crystallization is controlled better;

(3) if the cooling gas which does not react with the aluminum liquid is filled into the cooling gas path and then is discharged into the gas protection cavity through the gas outlet to be used as the protection gas, the arrangement of pipelines can be effectively reduced, and multiple purposes of the cooling gas are realized; or in order to reduce the cost, the gas outlets can be respectively arranged in the gas protection cavity and outside the crucible, when the protection gas needs to be filled, the compressed protection gas is filled in the cooling gas path and is discharged through the gas outlet positioned in the gas protection cavity, when the protection gas does not need to be filled in the gas protection cavity, the compressed air is filled in the cooling gas path and is then discharged through the gas outlet positioned outside the crucible, and the method is more flexible and has lower cost.

Drawings

FIG. 1 is a first schematic sectional view of an electronic grade high purity aluminum crystallization apparatus according to this embodiment;

FIG. 2 is a second schematic sectional view of the high-purity aluminum crystallization apparatus for electron level in this embodiment;

FIG. 3 is a third schematic sectional view of the electronic grade high purity aluminum crystallization apparatus in this embodiment;

fig. 4 is a schematic cross-sectional view of a second rotor having spiral inlet channels, vertical inlet channels, and outlet channels in this embodiment.

In the figure, 11, the first rotor; 12. a second swivel; 121. a positioning member; 13. a bolt; 2. a drive device; 21. a driving gear; 22. a driven gear; 3. a crucible; 31. a gas protection chamber; 32. a first sealing cover; 321. a first through hole; 33. a second sealing cover; 331. a second through hole; 4. the liquid level of the aluminum liquid; 5. cooling the gas circuit; 51. an air intake passage; 52. an air outlet channel; 53. An air inlet; 54. an air outlet; 541. a switch; 55. a compressor; 56. a first joint; 57. a second joint; 6. protecting the gas circuit; 61. a first air intake line; 62. a first gas outlet pipeline; 621. a gas pressure plug; 63. an inflator; 7. a graphite pipe sleeve; 8. a high temperature resistant tube; 9. and (4) a bracket.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

Examples 1,

The utility model provides an electronic level high-purity aluminum crystallization device, is the column setting including turning and drive arrangement 2, turns and vertically installs in the top of crucible 3, and the lower extreme of turning stretches into under the aluminium liquid level 4 in the crucible 3, and drive arrangement 2 is connected with the turning of crucible 3 top for the rotation is turned in the drive. Wherein the crucible 3 is preferably a graphite crucible 3.

Specifically, the driving device 2 preferably adopts a motor, the crucible 3 is provided with a support 9, the motor is fixedly installed on the support 9, and an output shaft of the motor is directly connected with the rotating body or is connected with the rotating body through a transmission structure. The transmission structure comprises a driving gear 21 and a driven gear 22, the driving gear 21 is sleeved on the outer side of an output shaft of the motor and synchronously rotates with the output shaft of the motor, the driven gear 22 is sleeved on the outer side of a rotating body and synchronously rotates with the rotating body, the driving gear 21 is directly meshed with the driven gear 22 or is matched with the driven gear through other gears, and finally the motor rotates to drive the driven gear 22 and the rotating body to rotate around a central shaft. In order to facilitate the support 9 and the motor to be taken down from the crucible 3 together with the rotating body, the support 9 is provided with a pull ring, so that the lifting device can be conveniently lifted.

It should be understood by those skilled in the art that the transmission structure may also include a main pulley, a secondary pulley and a belt, or the transmission structure may include a main sprocket, a secondary sprocket and a chain, as long as the rotation of the motor to rotate the rotating body is achieved.

A first sealing cover 32 is arranged at the top opening of the crucible 3, a first through hole 321 is arranged at the center of the first sealing cover 32, the lower end of the rotator extends into the crucible 3 through the first through hole 321, and the rotator can rotate relative to the first sealing cover 32.

In order to improve the heat insulation effect in the crucible 3 and reduce the temperature difference between the molten aluminum level 4 and the temperature below the molten aluminum level, a second sealing cover 33 is further arranged in the crucible 3, the second sealing cover 33 and the first sealing cover 32 are arranged at intervals, a second through hole 331 is arranged at the center of the second sealing cover 33, the lower end of the rotating body sequentially penetrates through the first through hole 321 and the second through hole 331 to extend into the crucible 3, and the rotating body can rotate relative to the second sealing cover 33.

In order to avoid the oxidation of the molten aluminum liquid level 4 due to contact with air and the moisture absorption of the molten aluminum, a gas protection cavity 31 is arranged above the molten aluminum liquid level 4 in the crucible 3, the gas protection cavity 31 is positioned between the molten aluminum liquid level 4 and a second sealing cover 33 in the embodiment, and a protection gas path 6 for introducing protection gas into the gas protection cavity 31 is arranged on the crucible 3. The protective gas can be one or more of inert gas or nitrogen, and the protective gas has the effect of isolating oxygen in the air from the high-temperature aluminum liquid.

In this embodiment, the protection gas circuit 6 includes a first gas inlet pipeline 61 and a first gas outlet pipeline 62, the first gas inlet pipeline 61 is connected to the external inflator 63 and the gas protection cavity 31, and is configured to fill the protection gas into the gas protection cavity 31, and the first gas outlet pipeline 62 is configured to communicate the gas protection cavity 31 with the outside, and is configured to discharge the air in the gas protection cavity 31. The first air inlet pipe 61 and the first air outlet pipe 62 can be implemented by passing through the first sealing cover 32 and the second sealing cover 33 directly through an air guiding tube as shown in fig. 1, wherein an air outlet end of the first air outlet pipe 62 is provided with an air pressure plug 621, when argon gas is introduced into the gas protection cavity 31, the air pressure plug 621 is opened for discharging air in the gas protection cavity 31, after the gas protection cavity 31 is filled with argon gas, the air pressure plug 621 is closed, and only when the air pressure in the gas protection cavity 31 is greater than a set value, the air pressure plug 621 of the first air outlet pipe 62 is opened again, and/or when the concentration of the protective gas in the gas protection cavity 31 is less than the set value, the air pressure plug 621 is opened and simultaneously the inflating device 63 is opened for filling the protective gas into the gas protection cavity 31. The diameter of the protective gas path 6 is 3mm, the pressure of the introduced argon is 0.15-0.3 MPa, and the ventilation time is 100 min.

Be equipped with cooling gas circuit 5 in turning, fill cooling gas into to cooling gas circuit 5 in to the turning and cool down, the aluminium liquid meets cold and then solidifies at the lower extreme of turning and piles up and form high-purity aluminium crystal to the realization is to the purification of aluminium liquid. The cooling gas may be compressed air.

Specifically, the cooling gas path 5 comprises a gas inlet channel 51 through which cooling gas flows from top to bottom and a gas outlet channel 52 through which cooling gas flows from bottom to top, the gas inlet channel 51 and the gas outlet channel 52 are communicated inside the swivel, a gas inlet 53 communicated with the gas inlet channel 51 is arranged at a part of the swivel above the crucible 3, and a gas outlet 54 communicated with the gas outlet channel 52 is arranged at a part of the swivel above the molten aluminum liquid level 4.

As shown in fig. 1, when the air inlet 53 is located at the top end of the swivel, a first joint 56 may be fixedly installed on the bracket 9, the first joint 56 is connected to the top end of the swivel in a rotating and sealing manner, and the compressor 55 connected to the first joint 56 charges air into the swivel, so as to charge air into the cooling air path 5.

As shown in fig. C, when the air inlet 53 is disposed on the side wall of the swivel above the crucible 3, a second joint 57 may be disposed on the bracket 9, the second joint 57 is sleeved outside the swivel and completely covers the outside of the air inlet 53, the swivel can rotate relative to the second joint 57, and the compressor 55 connected to the second joint 57 inflates air into the swivel, thereby inflating the cooling air path 5.

When the gas outlet 54 is only located above the molten aluminum liquid level 4 in the crucible 3, the cooling gas introduced into the cooling gas path 5 must be gas that does not react with the molten aluminum, such as inert gas, usually argon gas, on one hand, compressed argon gas is introduced into the cooling gas path 5 to cool the rotor, on the other hand, the inert gas discharged from the gas outlet 54 can also be used as protective gas to be filled into the gas protection cavity 31, and then is discharged through a first gas outlet pipeline 62 communicating the gas protection cavity 31 with the outside, so that the molten aluminum liquid level 4 can be prevented from contacting with air.

When the air outlet 54 is located outside the crucible 3, the air introduced into the cooling air passage 5 is preferably compressed air, which can effectively save the cost required for cooling the rotor.

As shown in fig. B, when a part of the gas outlet 54 is located above the molten aluminum liquid level 4 in the crucible 3, the position of the gas outlet 54 is provided with a switch 541, and when another part is located outside the crucible 3, compressed air and compressed argon gas can be alternately injected into the cooling gas path 5, when the gas protection chamber 31 above the molten aluminum liquid level 4 in the crucible 3 needs to be injected with protective gas, the compressed argon gas is injected into the cooling gas path 5 and is discharged into the gas protection chamber 31 through the gas outlet 54 located above the molten aluminum liquid level 4 in the crucible 3, when the gas protection chamber 31 above the molten aluminum liquid level 4 in the crucible 3 does not need to be injected with protective gas, the compressed air is injected into the cooling gas path 5 and is discharged through the gas outlet 54 located outside the crucible 3, so that the cooling gas path 5 can cool the rotating body, and can also charge protective gas into the gas protection chamber 31, the use is more flexible. In the actual use process, if it is detected that protective gas needs to be injected into the gas protection cavity 31, compressed protective gas is introduced into the cooling gas path 5, but the gas outlet 54 in the gas protection cavity 31 is opened in a delayed manner, so that air in the cold cutting gas path is emptied, and the condition that the purity of high-purity aluminum is influenced because the air in the cooling gas path 5 enters the crucible 3 is avoided.

The cooling gas of inertia accomplishes the crystallization to graphite cooling earlier, from upwards entering into gas protection chamber 31 down, can catch up the air (containing the moisture in oxygen and the air) of originally remaining in gas protection chamber 31, thereby ensure that whole gas protection chamber 31 fills up and is full of all inert gas, this and the inert gas that from the top down sent into gas protection chamber 31 clear away the air effect better, inert gas is from upwards down the time, can play the ascending effect of driving to the air, and from the top down carry inert gas, then can drive the air to aluminium liquid direction.

The inlet channel 51 is arranged spirally and/or vertically, and the outlet channel 52 is arranged spirally and/or vertically. The spiral arrangement aims to increase the retention time of the gas in the channel, thereby increasing the heat exchange time and improving the heat exchange effect.

Under the same circumstances of intake duct diameter, the intake duct that is the heliciform setting compares with the intake duct that is vertical setting, and the speed that the intake duct that is the heliciform setting fills into cooling gas can be slow a little, and this just makes it can be slow a little relatively to the cooling rate of turning to more be favorable to the accuracy of temperature to controlling, avoid the reduction by a wide margin of temperature, be favorable to purifying the aluminium crystal thing of higher purity. When the purity that needs the purification is not high, can directly select the intake duct of vertical setting, its speed that lets in cooling gas is fast, and is fast to the cooling rate of turning, can make aluminium liquid solidify the crystallization fast, and then improves purification efficiency.

Those skilled in the art should understand that the air inlet channel 51 that is the heliciform setting and the air inlet channel 51 that is vertical setting can set up simultaneously in turning, after the lower extreme outside of turning solidifies to pile up and forms a certain amount of high-purity aluminum crystal, can be through letting in cooling gas in the air inlet channel 51 to vertical setting, accelerate to turn and solidify accumulational high-purity aluminum crystal and cool down, thereby accelerate the aluminium liquid to solidify in the outside of high-purity aluminum crystal, improve purification efficiency, this process can cooperate temperature sensor to realize accurate control.

The rotator comprises a first rotator 11 and a second rotator 12 which are coaxially connected from top to bottom, the diameter of the second rotator 12 is larger than that of the first rotator 11, so that a part of air inlet channels 51 and all air outlet channels 52 are simultaneously arranged in the second rotator 12, the upper end of the second rotator 12 extends out of the first sealing cover 32, an air outlet 54 can be arranged on the part of the second rotator 12 outside the crucible 3, and then cooling air in the cooling air path 5 can be discharged out of the crucible 3.

The outside of the second rotating body 12 is sequentially sleeved with a high temperature resistant pipe 8 and a graphite pipe sleeve 7 from top to bottom, wherein the lower end of the graphite pipe sleeve 7 extends to the position below the molten aluminum liquid level 4, the top end of the graphite pipe sleeve 7 extends out of the second sealing cover 33, and the high temperature resistant pipe 8 is made of a heat insulating material and can reduce heat transfer to the upper sealing cover and the motor.

Specifically, a positioning part 121 is arranged at the joint of the first rotating body 11 and the second rotating body 12, the high temperature resistant pipe 8 and the graphite pipe sleeve 7 are sequentially sleeved on the second rotating body 12, the upper end of the high temperature resistant pipe 8 abuts against the positioning part 121, and then the bolt 13 penetrates through the bottom of the graphite pipe sleeve 7 to be in threaded connection with the second rotating body 12, so that the graphite pipe sleeve 7 and the high temperature resistant pipe 8 are installed on the second rotating body 12, and the graphite pipe sleeve 7 is a loss part, so that the graphite pipe sleeve 7 is installed in the mode, and the graphite pipe sleeve 7 is convenient to disassemble and assemble. Because of the excellent heat transfer effect of the graphite material, when the rotor is cooled, the low temperature of the cooling gas can be rapidly transferred to cool the graphite pipe sleeve 7, so that high-purity aluminum crystals are solidified and accumulated on the outer side of the graphite pipe sleeve 7, the crystallization effect is good, after the crystallization is finished, the rotor with the high-purity aluminum crystals is taken out of the crucible 3, is naturally cooled and cooled, then the graphite pipe sleeve 7 and the aluminum crystals are heated, and the aluminum crystals are rapidly expanded due to heating and naturally fall off from the outer side of the graphite pipe sleeve 7, so that the high-purity aluminum crystals can be more easily obtained compared with the prior art.

As shown in fig. 4, in the rotor, the spiral air inlet channel 51 is arranged around the vertical air inlet channel 51 (similar to the setting of concentric circles), the air inlet channel 51 extends from the first rotor 11 to the second rotor 12, and is communicated with the air outlet channel 52 at the bottom of the second rotor 12, and the spiral air inlet channel 51 is inflated through the air outlet 54 concentrically arranged on the first control first joint 56, so that the spiral air inlet channel 51 is inflated or the vertical air inlet channel 51 is inflated.

An electronic grade ultra-high purity aluminum crystallization method comprises the following steps:

1) putting a high-purity aluminum raw material with the purity of 4N5 or more into a crucible 3 to be melted into aluminum liquid, and setting the melting temperature to be 670-720 ℃;

2) fixedly installing a crystallization device above the crucible 3, keeping the graphite pipe sleeve 7 at the lower end of the rotating body concentric with the crucible 3 and extending below the liquid level 4 of the aluminum liquid;

3) starting a driving device 2 to drive the rotating body to drive the graphite pipe sleeve 7 to rotate, wherein the rotating speed is 90-120 rpm;

4) introducing cooling gas into a cooling gas path 5 in the rotator to start crystallization, and in the crystallization process, keeping the rotator to rotate at a constant speed and continuously introducing the cooling gas into the cooling gas path 5 to ensure that the outer surface of the graphite pipe sleeve 7 in contact with the aluminum liquid is directionally solidified to form a crystallized substance with a certain thickness;

5) when the set crystallization time is reached, closing the driving device 2, stopping introducing cooling gas into the cooling gas path 5, lifting out the crystallization device, removing crystals, and cutting off the head of the high-purity crystals by 40-60 mm to obtain the high-purity crystals; the head of the high purity crystal is preferably cut off by 50mm in this step to obtain a high purity crystal.

6) Pouring out the residual aluminum liquid in the crucible 3, and putting the high-purity crystallized product into the crucible 3 again to repeat the steps 1) -5) to obtain the ultrahigh-purity crystallized product.

Specifically, the preferable melting temperature of the high-purity aluminum raw material in the step 1) is 670-720 ℃, preferably 680 ℃, that is, the crucible 3 in the step 1) is heated to 680 ℃, then the heating is stopped, and when the temperature in the furnace is reduced to 670 ℃, the step 2) is carried out, that is, when the temperature in the furnace is reduced to 670 ℃, the crystallization device is arranged above the crucible 3.

The crystallization device in the step 2) is arranged in front of the upper part of the crucible 3, namely the graphite pipe sleeve 7 needs to be preheated before extending into the aluminum liquid, the preheating temperature is 500-700 ℃, and the preheating time is 20-60 min; the preheating temperature is preferably 600-700 ℃, and the preheating time is 20-40 min; further preferably, the preheating temperature is 670 ℃ and the preheating time is 35 min.

The graphite pipe sleeve 7 in the step 2) extends 300-600 mm below the molten aluminum liquid level 4, preferably 400-550 mm, and further preferably 450-500 mm.

After the crystallization device in the step 2) is installed above the crucible 3, protective gas such as argon and/or nitrogen is filled into the gas protection cavity 31 through the protective gas path 6, and air in the gas protection cavity 31 is exhausted, wherein the diameter of the protective gas path 6 is 3mm, the pressure of the introduced argon is 0.15-0.3 MPa, and the ventilation time is 100 min.

Or, after the crystallization device is installed above the crucible 3, the gas charging device 63 is started to charge the protective gas into the cooling gas path 5, so that the protective gas is used as the cooling gas to cool the rotating body, is discharged from the gas outlet and is charged into the gas protection cavity 31 to play the role of the protective gas again.

And 4) introducing normal-temperature compressed air of 200-800L/min into a cooling air path 5 in the rotating body in the step 4), optimally introducing normal-temperature compressed air for 10min at 200L/min, then introducing normal-temperature compressed air for 90min at 700L/min, and discharging the compressed air into air through an air outlet 54 of a cooling air path positioned outside the crucible 3.

When the selected crystallization device is provided with the gas outlets 54 outside the crucible 3 and in the gas protection cavity 31, the optimization can also be that after the crystallization device is installed above the crucible 3, compressed argon is introduced at 200L/min for 10min, the introduced argon flows through the cooling gas path 5 in the rotator and is discharged into the gas protection cavity 31, and all air in the gas protection cavity 31 is discharged; after the rotator starts to rotate, compressed air at normal temperature is introduced for 90min at the speed of 700L/min to cool the rotator, and the introduced argon can cool the rotator and prevent aluminum liquid from contacting with air when flowing along the rotator, so that the purity of the obtained crystallized product is improved.

The crystallization time in the step 4) is 90-120 min, preferably 95-110 min, and more preferably 100 min.

And 5) after the crystallization device is taken out, quickly cooling the graphite pipe sleeve 7 and high-purity crystal outside the graphite pipe sleeve 7 in the air, cooling to 200-250 ℃, and then heating the high-purity crystal at 600-650 ℃ until the high-purity crystal automatically falls off from the graphite pipe sleeve 7.

Further, the crucible 3 and the graphite pipe sleeve 7 outside the rotator are coated with high-temperature-resistant and oxidation-resistant aluminum-based coatings.

By the crystallization method for preparing the electronic grade ultra-high purity aluminum, a high purity aluminum raw material with the purity of 4N5 or more is selected to be melted into aluminum liquid in a crucible, and a crystallization device is inserted into the crucible, so that a graphite pipe sleeve extends into the aluminum liquid by the depth of 400-600 mm; starting a driving device to drive the graphite pipe sleeve to synchronously rotate, then introducing cooling gas into the rotating body to start crystallization, and keeping the rotating speed of a crystallization machine and the stability of the cooling gas in the crystallization process to directionally solidify and separate out inverted mushroom-shaped high-purity crystallized substances with a certain thickness on the surface of the graphite pipe sleeve contacted with the aluminum liquid; when the set crystallization time is up, firstly stopping the rotation of the crystallization device, then closing a vent valve of an air cooling system of the crystallization device, lifting the crystallization device out of a graphite crucible, removing crystals on a graphite pipe sleeve below the crystallization machine, cutting off the head of the crystals by 40-60 mm to obtain high-purity crystals, pouring out the residual aluminum liquid in the crucible, and putting the high-purity crystals into the crucible again to repeat crystallization to obtain the crystals with higher purity.

Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that modifications and variations of the present invention are possible to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.