JP2022022907A - Method for producing high-purity silicon powder, high-purity silicon powder and system for producing high-purity silicon powder - Google Patents

Abstract

To efficiently produce a high-purity silicon powder using a silicon end material as a raw material.SOLUTION: A method for producing a high-purity silicon powder comprises the steps of: producing a high-purity silicon cobble stone from a silicon block by using a ball mill for producing cobble stone in order to efficiently produce a high-purity silicon powder using a silicon end material as a raw material; and charging the cobble stone and an object to be pulverized made of silicon into a container of a powder producing ball mill larger than the ball mill for producing cobble stone and rotating the container.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing high-purity silicon powder, a high-purity silicon powder, and a high-purity silicon powder production system.

In the above technical field, Patent Document 1 discloses a technique relating to a method for producing silicon fine particles.

Japanese Unexamined Patent Publication No. 2011-132105

However, with the technique described in the above document, it has not been possible to efficiently produce high-purity silicon powder using silicon offcuts as a raw material.

In order to achieve the above object, the method according to the present invention
The process of making high-purity silicon boulders from silicon blocks using a ball mill for boulder manufacturing,
A step of putting the boulder and a silicon object to be crushed into a container of a ball mill for powder manufacturing, which is larger than the ball mill for boulder manufacturing, and rotating the container.
It is a manufacturing method of high-purity silicon powder containing.

In order to achieve the above object, the system according to the present invention is
A ball mill for making high-purity silicon boulders from silicon blocks, and a ball mill for making boulders.
A crusher for crushing silicon scraps to produce silicon objects to be crushed,
A ball mill for producing powder, which is larger than the ball mill for producing boulders and has a container into which the boulders and the silicon object to be crushed are charged, and a rotating portion for rotating the container.
It is a manufacturing system of high-purity silicon powder equipped with.

According to the present invention, high-purity silicon powder can be efficiently produced using silicon offcuts as a raw material.

It is a schematic diagram from the silicon block to the boulder being made in the manufacturing method of the high-purity silicon powder which concerns on 1st Embodiment. It is a schematic diagram of the ball mill (barrel polishing machine) for bouldering used in the manufacturing method of the high-purity silicon powder which concerns on 1st Embodiment. It is a schematic diagram which showed the inside of the pot of the ball mill for boulders used in the manufacturing method of the high-purity silicon powder which concerns on 1st Embodiment. It is a schematic diagram of the jaw crusher used for coarsely pulverizing silicon offcuts. It is a schematic diagram of the roll crusher used for medium crushing silicon offcuts. It is an enlarged view of the roll part of the roll crusher used for medium crushing silicon offcuts. It is a schematic diagram of the ball mill for powder manufacturing used in the manufacturing method of the high-purity silicon powder which concerns on 1st Embodiment. It is explanatory drawing which showed the state in the container of the ball mill for powder manufacturing in the manufacturing method of the high-purity silicon powder which concerns on 1st Embodiment. It is a block diagram of the high-purity silicon powder manufacturing system which concerns on 5th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail exemplary with reference to the drawings. However, the components described in the following embodiments are merely examples, and the technical scope of the present invention is not limited to them.

[First Embodiment]
The method for producing the high-purity silicon powder according to the first embodiment will be described. The method for producing a high-purity silicon powder according to the present embodiment is a process of producing a high-purity silicon ball stone from a silicon block using a ball mill for producing a ball stone, and a ball stone in a container of a ball mill for producing powder, which is larger than the ball mill for producing ball stone. And the process of putting a silicon object to be crushed and rotating the container. Hereinafter, the two steps will be described in detail.

<Cobblestone manufacturing process>
FIG. 1 is a schematic diagram from a silicon block to the production of a high-purity silicon boulder (hereinafter referred to as “cobblestone”). As shown in FIG. 1, the boulder 104 is a silicon block 103 (150 mm or less) produced by roughly crushing a silicon cylinder 101 of about 150 mm to 500 mm and a silicon ingot 102 (large square lumber) with a hammer. It is produced by removing edges 131 to 134 with a ball mill for producing boulders. The silicon cylinder 101 and the silicon ingot 102 are silicon scraps 100. Here, the silicon scrap material 100 means a silicon material generated as a derivative product or a waste material in the process of manufacturing a silicon wafer from a silicon ingot. In the process of making boulders, it is possible to select a silicon material suitable for the raw material of the silicon block from the silicon scraps. Suitable silicon offcuts as raw materials for silicon blocks include, for example, the top and tail of silicon ingots, and silicon ingots that have failed to crystallize.

(Silicon block)
The silicon cylinder 101 and the silicon ingot 102 are defective products that do not meet the certain qualities required for silicon-related products, and are usually treated as waste materials or derivative products. The silicon cylinder 101 and the silicon ingot 102 are raw materials for the silicon block 103. The silicon cylinder 101 and the silicon ingot 102 have a size sufficient to generate the silicon block 103.

The silicon block 103 is generated by coarsely crushing a silicon cylinder 101 and a silicon ingot 102 using a hammer or the like. The silicon block 103 has a particle size of 150 mm or less, and has edges 131 to 134 at its ends. When the edges 131 to 134 of the silicon block 103 are removed, the silicon block 103 becomes a boulder 104. The edges 131 to 134 of the silicon block 103 are removed by using a ball mill for producing boulders.

(Ball mill for cobblestone manufacturing)
FIG. 2A is a schematic view of a ball mill (barrel grinding machine) used for manufacturing boulders. Here, a barrel grinding machine is used as a ball mill for producing boulders. As shown in FIG. 2A, the barrel polishing machine 200 includes a rotating disk 202 located at both left and right ends inside the barrel 201, and four pots (polishing tanks) attached to the rotating disk 202. The four pots 203 to 206 are attached to the flat surface portion of the turntable 202 so as to be located at equal intervals. The pots 203 to 206 of the barrel grinding machine 200 have an octagonal shape of 20 to 80 L and include four pots. The internal volume of the pots 203 to 206 is 20 to 80 L. Pots 203-206 have an octagonal cross section. The silicon block 103 can be put into the pots 203 to 206.

Five to six silicon blocks 103 are put into one pot, and pots 203 to 206 in which the silicon blocks 103 are put are set inside the barrel 201. When the turntable 202 of the barrel grinding machine 200 is rotated, the pots 203 to 206 in which the silicon block 103 is inserted revolve. As the pots 203 to 206 revolve, the edges 131 to 134 are removed by repeated collisions with the inner walls of the pots 203 to 206. Since the barrel grinding machine is capable of rotating the pot at high speed and is suitable for removing burrs from machined products, it can be suitably used as a ball mill for producing ball stones.

FIG. 2B is a schematic view showing the state inside the pot 203 before and after the barrel polishing treatment. As shown in FIG. 2B, the silicon block 103 before the barrel polishing process has a plurality of edges 131 to 134. When the pot 203 revolves, the edges 131 to 134 of the silicon block 103 are removed from the inside of the pot 203, and the silicon block 103 becomes a boulder 104 having a particle size of 30 to 150 mm. The edges 131 to 134 removed from the silicon block 103 when the boulder 104 is manufactured can be used as a silicon scrap material as a raw material for a silicon object to be crushed.

As described above, in the step of making a high-purity silicon boulder from the silicon block, the boulder (FIG. 2B) is generated by removing the edges 131 to 134 of the silicon block 103. The conditions for manufacturing the boulder 104 can be appropriately set. For example, the rotation speed of the turntable 202 can be set to 100 to 200 rpm, and the rotation time can be set to 0.5 to 1.0 hour.

The boulder 104 does not have the edges 131-134 present in the silicon block 103. Therefore, if the boulder 104 is used as the ball for crushing the ball mill, the presence of the edges 131 to 134 does not adversely affect the fine pulverization of the silicon object to be crushed by the ball mill. As a result, in the method for producing high-purity silicon powder of the present embodiment, the particle size of the obtained high-purity silicon powder can be adjusted with high accuracy.

<Powder manufacturing process>
This step is a step of producing high-purity silicon powder from the object to be crushed by colliding the boulder with the silicon object to be crushed (hereinafter referred to as “the object to be crushed”) using a ball mill for producing powder.

(Material to be crushed)
The object to be pulverized is produced by coarsely pulverizing silicon offcuts and then medium pulverizing. Suitable silicon scraps as a raw material for the object to be crushed include fragments of a silicon wafer, a silicon material generated when a silicon block is roughly pulverized, and an edge removed from the silicon block.

(Rough crushing of silicon scraps)
FIG. 3 is a schematic view of a jaw crusher 300 used for coarsely pulverizing silicon offcuts. The jaw crusher 300 coarsely crushes the silicon offcuts 304 to produce a silicon coarsely crushed product 305 (hereinafter referred to as "coarse crushed material") having a particle size of about 10 to 30 mm.

The jaw crusher 300 includes a fixed tooth 301 mounted perpendicular to the installation surface and a moving tooth 303 movable by a crank mechanism 302. The moving tooth 303 reciprocates in the front-rear direction with a small amplitude. The silicon scrap 304 thrown into the gap formed between the fixed tooth 301 and the moving tooth 303 is sandwiched between the fixed tooth 301 and the moving tooth 303 and roughly crushed. The coarsely pulverized silicon scrap 304 becomes a coarsely pulverized product 305. The rough crushing of the silicon offcuts 304 by the jaw crusher 300 may be performed a plurality of times by setting appropriate conditions.

It is preferable that the fixed tooth 301 and the moving tooth 303 are made of a material having the same degree as that of the silicon end material 304 or having a hardness higher than that of the silicon end material 304. When the hardness of the fixed tooth 301 and the moving tooth 303 is high, the fixed tooth 301 and the moving tooth 303 are less likely to be worn, and metal impurities are not mixed into the silicon powder as a contaminant, which is preferable. As the material of the fixed tooth 301 and the moving tooth 303, alumina, quartz and the like can be exemplified.

(Medium crushed material)
FIG. 4A is a schematic view of a roll crusher 400 used for medium pulverizing a coarsely pulverized product 305. The roll crusher 400 can strongly crush the coarse pulverized product 305 at a low speed rotation. The roll crusher 400 includes rotating rolls 401 and 402 that rotate in opposite directions to each other. When the coarsely crushed material 305 is charged from the charging port 403, the coarsely crushed material 305 is medium-crushed by a rotary roll to become a crushed material 405 having a particle size of about 1.0 mm. The generated object to be crushed 405 passes through the discharge pipe 404 and accumulates at the bottom of the roll crusher 400. The medium crushing of the coarse crushed product 305 by the roll crusher 400 may be performed a plurality of times by setting appropriate conditions.

FIG. 4B is an enlarged view showing a state in which the coarsely pulverized material 305 is medium pulverized and the material to be crushed 405 is produced. As shown in FIG. 4B, the coarsely pulverized material 305 is sandwiched between the roll gaps formed between the rotary rolls 401 and the rotary rolls 402, and is medium-crushed by compression by two rotary rolls that rotate in opposite directions. It becomes the object to be crushed 405. The coarsely crushed material 305 becomes a crushed material 405 by being pulverized in the middle. The particle size of the object to be crushed 405 can be adjusted by appropriately setting a roll gap formed between the two rotating rolls.

The rotary roll preferably has a hardness similar to that of the silicon offcuts or higher than that of the silicon offcuts. It is preferable that the material of the rotating roll has a high hardness because it can suppress contamination of silicon powder due to metal impurities. For example, the material of the rotary roll is preferably alumina or silicon.

(Ball mill for powder manufacturing)
FIG. 5 is a schematic view of a ball mill for producing powder used for finely pulverizing an object to be pulverized. The ball mill 500 includes a cylindrical container 501. The ball mill 500 is provided with columns 502 and 503 at both ends of the container 501. Both ends of the container 501 are supported by columns 502 and 503. The container 501 rotates in a predetermined direction by rotating the rotary belt 504 attached to the left end portion. The rotary belt 504 is rotated by the power generated from the drive unit 505. The internal state of the container 501 can be observed from the door scope 506 attached to the side surface of the container 501.

A net 507 and a cover 508 can be attached to the door scope 506. The cover 508 can cover the door scope 506 and serves as a lid for the container 501. After the lapse of a predetermined time, when the fine pulverization of the object to be pulverized is completed, the cover 508 can be removed and the inside of the container 501 can be observed from the door scope 506. If only the cover 508 is removed and the net 507 is attached to the door scope 506, the net 507 serves as a sieve, and only high-purity powder having a predetermined particle size can be taken out from the container 501. Also, by removing the net 507 and the cover 508, the boulders and the manufactured high-purity silicon powder can be taken out from the container 501.

The ball mill 500 is a ball mill larger than the ball mill for producing boulders. By making the ball mill 500 larger than the ball mill for cobblestone production, a large amount of objects to be pulverized can be finely pulverized to efficiently produce high-purity silicon powder. The capacity of the container 501 is preferably 600 liters or more. When the capacity of the container 501 is 600 liters or more, it is preferable because a large amount of the object to be pulverized can be finely pulverized by one pulverization treatment (rotation speed 45 rpm, pulverization time 1.0 hour).

A high-purity silicon powder is produced by putting a predetermined amount of boulders 104 and an object to be crushed into a container 501 and performing a ball mill pulverization treatment under predetermined conditions.

(Condition inside the container of the ball mill for powder manufacturing)
FIG. 6 is an explanatory diagram showing the internal state of the container 600 of the powder mill for manufacturing ball mill. The container 600 includes a container lining 601. The container lining 601 may be, for example, alumina. The container lining 601 is preferably silicon or the like having the same degree of hardness as the silicon offcuts or higher hardness than the silicon offcuts. Further, the container lining 601 may be made of high-purity silicon. It is preferable that the container lining 601 is made of high-purity silicon because contamination of silicon powder due to metal impurities can be suppressed.

The boulders 104 (cobblestones 602, 603, 604, 605) and the object to be crushed 405 are put into the container 600 at a predetermined ratio. The boulder 104 has a constant particle size distribution. The boulders 602, 603, 604, and 605 have different particle sizes. The boulders 104 (cobblestones 602, 603, 604, 605) and the object to be crushed 405 are both composed of high-purity silicon. The method for producing high-purity silicon powder according to the present embodiment can be said to be a method for producing high-purity silicon powder using silicon co-rubbing.

The container 600 rotates in the direction of arrow 602. As the container 600 rotates, the boulders 104 (cobblestones 602, 603, 604, 605) and the object to be crushed 405 collide with each other. Further, the boulders 104 (cobblestones 602, 603, 604, 605) and the object to be crushed 405 also collide with the container lining 601 and wear.

The boulders 104 (cobblestones 602, 603, 604, 605) wear by colliding with the object to be crushed 405 and the container lining 601. The particle size of the boulder 104 gradually decreases with the rotation of the container 600. The worn boulder 104 becomes a high-purity silicon powder 606. Further, the object to be crushed 405 collides with the boulders 104 (cobblestones 602, 603, 604, 605) and the container lining 601 to be finely pulverized to become high-purity silicon powder 606. High-purity silicon powder is generated from the boulder 104 and the object to be crushed 405. When the container lining 601 is made of silicon, the high-purity silicon powder is also generated from the container lining 601.

The rotation speed of the container 600 is preferably 40 to 50 rpm. If the rotation speed of the container 600 is set in the above range, the crushing treatment time of the object to be crushed 405 can be set to 0.5 to 2.0 hours.

In this way, the object to be crushed 405 existing in the container 600 is finely pulverized by repeatedly colliding with the boulders 104 (cobblestones 602, 603, 604, 605) and the container lining 601 and has an average particle size of 30. It becomes a high-purity silicon powder 606 of about 40 μm.

(Classification of high-purity silicon powder)
The produced high-purity silicon powder 606 is classified by sieving according to a conventional method. The classification of the high-purity silicon powder 606 can be performed, for example, by using a circular sieve and selecting an appropriate sieve having a mesh size in the range of 50 to 120 μm.

As described above, according to the method for producing high-purity silicon powder of the present embodiment, high-purity silicon powder can be efficiently produced by using silicon offcuts as a raw material.

[Second Embodiment]
The method for producing high-purity silicon powder according to the present embodiment is different from the above-described embodiment in that the ratio between the weight of the boulders charged into the ball mill for producing powder and the weight of the object to be crushed is set. .. Since other configurations and steps are the same as those in the above embodiment, detailed description thereof will be omitted.

The method for producing high-purity silicon powder of the present embodiment has a technical feature in that the ratio of the weight of the object to be crushed to the weight of the boulder is set to 1: 3. If the weight of the boulder is less than 3 with respect to the weight of the object to be crushed 1, the fine pulverization of the object to be crushed does not proceed, which is not preferable. On the other hand, when the weight of the boulder exceeds 3 with respect to the weight 1 of the object to be crushed, the weight of the object to be crushed is relatively small in the container of the ball mill for powder production, and the production efficiency of high-purity silicon powder is lowered. Therefore, it is not preferable.
As described above, according to the method for producing high-purity silicon powder of the present embodiment, by adjusting the ratio between the total weight of the object to be crushed and the total weight of the boulders, high-purity and stable quality silicon is used. The powder can be manufactured efficiently.
It is preferable to set the ratio of the weight of the object to be crushed to that of the boulder to 1: 3. If the weight of the object to be crushed exceeds 3 with respect to the weight of 1 boulder, it takes time to crush the object to be crushed, which is not preferable.

[Third Embodiment]
In the method for producing high-purity silicon powder according to the present embodiment, as compared with the above embodiment, in the step of rotating the container of the ball mill for producing powder, the weight of the ball stone existing in the container is set within a certain range. It differs in that it is. Since other configurations and steps are the same as those in the above embodiment, detailed description thereof will be omitted.

In the step of rotating the container of the method for producing high-purity silicon powder of the present embodiment, the weight of the boulder is 1/4 of the total weight of the weight of the object to be crushed and the weight of the boulder existing in the container. It is set in the range of ~ 3/4. That is, in the method for producing high-purity silicon powder of the present embodiment, the weight of the boulders existing in the container is set within a certain range to control the weight of the boulders that collide with the object to be crushed. It is possible to stabilize the quality of high-purity silicon powder.

When the container of the ball mill for powder production is rotated under certain conditions, the ball stones existing in the container gradually wear as the container rotates. The grain size of the worn boulders is smaller than the grain size of the boulders immediately after being placed in the container of the ball mill for powder production. For example, a boulder (large) having a particle size of about 150 mm existing in a container of a ball mill for powder production becomes a boulder (medium) having a particle size of about 80 mm due to wear. Further, the boulder (medium) having a particle size of about 80 mm becomes a boulder (small) having a particle size of about 40 mm due to wear, and finally becomes a high-purity silicon powder.

Here, the weight of the high-purity silicon powder produced under predetermined conditions is approximately equal to the sum of the weights of the object to be ground and the weight of the worn boulders. Therefore, the weight of the manufactured high-purity silicon powder is measured. Then, the weight of the boulder to be newly replenished is the amount corresponding to the weight of the manufactured high-purity silicon powder minus the weight of the input material to be crushed. When a new high-purity silicon powder is manufactured, a predetermined amount of boulders is newly replenished in the powder manufacturing ball mill. As described above, in the method for producing high-purity silicon powder of the present embodiment, the weight of the boulders existing in the container of the ball mill for producing powder is constant by repeatedly discharging the produced high-purity silicon powder and replenishing the boulders. Can be kept in.

Specifically, 300 kg of ball stones and 100 kg of the object to be crushed are put into a container of a ball mill for producing powder, and the first ball mill pulverization is performed under the conditions of a rotation speed of 45 rpm and a pulverization time of 1.0 hour. When the first ball mill pulverization is completed, the weight of the boulders present in the container of the ball mill for producing powder is reduced by 1.0 to 2.0% by weight. Therefore, in order to keep the weight of the ball stones existing in the container of the ball mill for powder manufacturing constant, 3.0 to 6.0 kg of ball stones corresponding to the reduced weight of the ball stones are newly replenished in the container of the ball mill for powder manufacturing. ..

Next, the container of the ball mill for producing powder is subjected to the second ball mill pulverization under the conditions of a rotation speed of 45 rpm and a pulverization time of 1.0 hour. When the second ball mill pulverization is performed, the weight of the boulders present in the container of the ball mill for powder production is reduced. Replenish the corresponding boulders with the reduced weight of the boulders. Further, under the same conditions, a third ball mill pulverization is performed. Even after the third ball mill pulverization, the boulders corresponding to the reduced weight of the boulders are newly replenished in the container of the ball mill for powder production.

As described above, according to the present embodiment, the weight of the boulder is determined by setting the weight obtained by subtracting the weight of the charged object to be charged from the weight of the manufactured high-purity silicon powder as the weight of the newly charged boulder. It can be kept constant and the quality of the manufactured high-purity silicon powder can be stabilized.
In the step of rotating the container 401, the weight of the boulder is set to 1/4 to 3/4 of the total weight of the weight of the object to be crushed 306 existing in the container 401 and the weight of the boulder 104. Can be done.
By setting the weight of the boulder within a certain range with respect to the total weight of the weight of the object to be crushed 306 and the weight of the boulder 104 existing in the container 401, the amount of the boulder in contact with the object to be crushed can be determined. It can be controlled to stabilize the quality of the silicon powder.

[Fourth Embodiment]
<High-purity silicon powder>
This embodiment is a high-purity silicon powder produced by the method for producing a high-purity silicon powder according to the above embodiment. The amount of metal impurities such as iron (Fe), aluminum (Al), chromium (Cr), and zirconium (Zr) contained in the produced high-purity silicon powder was measured by inductive plasma mass spectrometry.

<Example>
The high-purity silicon powder of this embodiment was produced under the following conditions.
(Manufacturing of boulders)
A high-purity silicon ingot was hand-ground to produce a silicon block having a particle size of 150 mm or less. A barrel grinding machine was used as a ball mill for manufacturing boulders. Five to eight silicon blocks were put into four pots provided in the barrel polishing machine, and the pots were revolved under the conditions of a rotation speed of 150 rpm for 30 minutes to polish the silicon blocks in barrels. The silicon block became a boulder with the edges removed by barrel polishing.

(Manufacturing of material to be crushed)
High-purity silicon ingots were hand-ground to produce silicon scraps with a particle size of 100 mm or less. Silicon scraps were coarsely ground using a jaw crusher. The obtained crude crushed product was medium crushed using a roll crusher. The silicon scrap after medium crushing was used as the object to be crushed. The roll gap of the roll crusher was set to 1.0 mm.

(Manufacturing of high-purity silicon powder)
As a ball mill for manufacturing silicon powder, a ball mill having an internal volume of 600 L was used. 300 kg of the boulder and 100 kg of the object to be crushed were put into a ball mill for silicon production. The crushing conditions of the ball mill were a ball mill rotation speed of 45 rpm and a crushing treatment time of 60 minutes. After finely pulverizing the ball mill under the above conditions, high-purity silicon powder was obtained.

(Classification conditions)
The high-purity silicon powder obtained after fine grinding with a ball mill was classified using a circular sieve having a mesh of 100 μm. After classification, a high-purity silicon powder under a sieve was used as a product.

(Evaluation of high-purity silicon powder)
The average particle size of the high-purity silicon powder of this embodiment was measured. The average particle size of the high-purity silicon powder was D50 = 35 μm. Impurity analysis of high-purity silicon powder was performed by high frequency inductively coupled plasma (ICP) analysis. The analysis results are shown in Table 1.

As a result, as is clear from Table 1, it was found that the amount of metal impurities contained in the high-purity silicon powder produced in the above embodiment was about 50 ppm. That is, the high-purity silicon powder produced in the above embodiment hardly contains metal impurities generated in the manufacturing process as a contaminant, and has high quality (> 99.99% high purity) almost equivalent to that of a silicon wafer. It became clear that it was doing.

As described above, since the high-purity silicon powder of the present embodiment has high quality, it can be suitably used for manufacturing lithium secondary batteries, dissolution raw materials for solar cells, polysilicon thin films, alloying agents and the like.

[Fifth Embodiment]
<High-purity silicon powder manufacturing system>
FIG. 7 is a block diagram of the high-purity silicon powder manufacturing system 700 of the present embodiment. As shown in FIG. 7, the high-purity silicon powder manufacturing system 700 includes a ball mill 701 for manufacturing a ball stone, a crusher 704 for manufacturing a crushed object, and a container for charging the ball stone and the object to be crushed. It includes a ball mill 702 for producing powder and a rotating portion for rotating the container.

The silicon block is put into a ball mill 701 for producing boulders, and the edges are removed to form boulders. The boulders are put into a ball mill 702 for producing powder. The silicon scrap is roughly crushed by the jaw crusher 741. The coarsely crushed product is medium crushed by the roll crusher 742 to become a crushed product. The object to be crushed is put into a ball mill 702 for producing powder. High-purity silicon powder is produced by rotating the container of the powder mill 702 for producing powder under predetermined conditions.

As described above, according to the high-purity silicon powder manufacturing system of the present embodiment, high-purity silicon powder can be manufactured using a silicon block and silicon offcuts as raw materials.

[Other embodiments]
Although the invention of the present application has been described above with reference to the embodiments, the invention of the present application is not limited to the above-described embodiment. Various changes that can be understood by those skilled in the art can be made to the structure and details of the present invention within the technical scope of the present invention. Also included in the technical scope of the invention are systems or devices in any combination of the different features contained in each embodiment.

Claims (9)

The process of making high-purity silicon boulders from silicon blocks using a ball mill for boulder manufacturing,
A step of putting the boulder and a silicon object to be crushed into a container of a ball mill for powder manufacturing, which is larger than the ball mill for boulder manufacturing, and rotating the container.
A method for producing high-purity silicon powder including. The method for producing high-purity silicon powder according to claim 1, wherein the silicon block and / or the silicon object to be crushed is silicon scrap generated in the process of producing a silicon wafer from a silicon ingot. The method for producing high-purity silicon powder according to claim 1 or 2, wherein the boulder has a silicon purity of 99.99% or more. The method for producing high-purity silicon powder according to any one of claims 1 to 3, wherein the container lining of the ball mill for producing boulders is made of high-purity silicon. The method for producing high-purity silicon powder according to any one of claims 1 to 4, wherein the container lining of the ball mill for producing powder is made of high-purity silicon. The method for producing high-purity silicon powder according to any one of claims 1 to 5, wherein the ratio of the total weight of the silicon object to be crushed to the total weight of the boulders is 1: 3. In the step of rotating the container, the weight of the boulder is 1/4 to 3/4 of the total weight of the weight of the silicon object to be crushed and the weight of the boulder existing in the container. The method for producing a high-purity silicon powder according to any one of claims 1 to 6. A high-purity silicon powder produced by the method for producing a high-purity silicon powder according to any one of claims 1 to 7. A ball mill for making high-purity silicon boulders from silicon blocks, and a ball mill for making boulders.
A crusher for crushing silicon scraps to produce silicon objects to be crushed,
A ball mill for producing powder, which is larger than the ball mill for producing boulders and has a container into which the boulders and the silicon object to be crushed are charged, and a rotating portion for rotating the container.
High-purity silicon powder manufacturing system with.

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