WO2020226253A1 - Method for producing silicon powder material - Google Patents

Abstract

The present invention relates to a method for producing a silicon powder material. A method for producing a silicon powder material according to an embodiment of the present invention comprises: a step (S100) for producing a fine glass powder by fine powdering a silica (SiO₂)-containing glass material; a step (S200) for ball milling the fine glass powder; a step (S300) for acid-treating the ball milled fine glass powder; and a step (S400) for producing a silicon powder by reducing the silica contained in the acid-treated fine glass powder.

Description

Method of manufacturing silicon powder material

The present invention relates to a method of manufacturing a silicon powder material, and more particularly, to a method of manufacturing a high-purity silicon powder material using a glass substrate of a waste LCD panel or glass scrap generated in an LCD panel manufacturing process.

As the amount of waste LCD panels increases exponentially, technologies for collecting and recycling waste LCD panels are being studied. Waste LCD panel is composed of case, glass substrate, frame, panel, driving circuit, backlight unit, among which, as a method of recycling waste glass substrate, waste LCD glass is put into the cement manufacturing process to manufacture cement clinker. Alternatively, it has been proposed to be used as a raw material for producing foamed glass for insulation by adding a foaming agent to waste LCD glass powder and firing. However, such a recycling method has a limitation in commercialization due to its complicated manufacturing process and low economy. Among the waste LCD panels, glass substrates are known to have a high composition ratio of 40 to 50% and contain up to 70% of silica (SiO ₂ ). In addition, in the process of manufacturing an LCD panel, a large amount of glass scrap containing silica is generated. Therefore, there is a need for research and development to convert the glass substrate or scrap into a material. In particular, silicon powder is an anode material having high capacity and high power characteristics of a high-capacity lithium-ion battery, and can be used as an alternative material for commercial graphite-based anodes. If it can be synthesized, it can be a recycling method with high economic efficiency.

The present invention is to solve the problems of the prior art described above, one aspect of the present invention is to remove impurities by pre-treating the glass substrate of the waste LCD panel or the glass scrap generated in the LCD manufacturing process by ball milling and acid treatment. And, to provide a method for producing a silicon powder material for synthesizing high-purity silicon powder by reducing and heat treating the silica of the glass material as a raw material.

A method for manufacturing a silicon powder material according to an embodiment of the present invention comprises the steps of generating a fine glass powder by finely powdering a glass material containing silica (SiO ₂ ); Ball milling the fine glass powder; Acid-treating the ball milled fine glass powder; And reducing the silica contained in the acid-treated fine glass powder to prepare a silicon powder.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, the glass material may be a glass substrate separated from a waste LCD panel.

In addition, in the method of manufacturing a silicon powder material according to an embodiment of the present invention, the glass material may be glass scrap generated in the LCD panel manufacturing process.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, the step of generating the fine glass powder comprises: pulverizing and pulverizing the glass material; And selecting the micronized glass material by sieving.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, the ball milling may be a wet ball milling.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, the acid treatment may be treatment by immersing the fine glass powder in an acid solution.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, the acid solution may be an aqueous nitric acid solution.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, the fine glass powder may be immersed in the acid solution at 50 to 70° C. for 65 to 80 hours.

In addition, in the method for manufacturing a silicon powder material according to an embodiment of the present invention, between the acid treatment step and the silica reduction step, washing and freeze-drying the acid-treated fine glass powder; may further include .

In addition, in the method of manufacturing a silicon powder material according to an embodiment of the present invention, the silicon powder may contain 99.0 to 99.9 wt% of silicon (Si), the remainder of aluminum (Al), and other unavoidable impurities.

Further, in the method of manufacturing a silicon powder material according to an embodiment of the present invention, the other inevitable impurities may include boron (B), calcium (Ca), and strontium (Sr).

Features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, terms or words used in the present specification and claims should not be interpreted in a conventional and dictionary meaning, and the inventor may appropriately define the concept of the term in order to describe his or her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

According to the present invention, since it is possible to synthesize high-purity silicon powder in a simple and economical manner by using silica-containing glass such as a glass substrate of a waste LCD panel or glass scrap generated in the LCD manufacturing process, waste LCD panel and glass scrap It can be used as a recycling method.

In addition, the high-purity silicon powder synthesized therefrom can be used as an anode material having high capacity and high output characteristics of a lithium-ion battery, and thus contribute to the development of an electrode material that replaces a commercial graphite-based anode.

1 and 2 are flow charts of a method of manufacturing a silicon powder material according to an embodiment of the present invention.

3 is an elemental composition (a), scanning electron microscope (SEM) images (b, d, f, h), and particle size analysis results of glass powder samples prepared according to Example 1 and Comparative Example 1 (c, e, g, i).

4 is an X-ray diffraction (XRD) analysis result (a) of silicon powder samples prepared according to Example 2 and Comparative Example 2, and energy dispersive X-ray spectroscopy (EDS) mapping with scanning electron microscope (SEM) images. This is the image analysis result (b).

5 is a process chart for manufacturing an electrode according to Example 3 (a), and galvanostatic charge/discharge (b), cyclic voltammetry (c), and rate capability performance (d) of the electrodes manufactured according to Example 3 and Comparative Example 3 ) This is the evaluation result.

Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. In adding reference numerals to elements of each drawing in the present specification, it should be noted that, even though they are indicated on different drawings, only the same elements are to have the same number as possible. Hereinafter, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the subject matter of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are flow charts of a method of manufacturing a silicon powder material according to an embodiment of the present invention.

1 and 2, the method of manufacturing a silicon powder material according to an embodiment of the present invention is a step of generating a fine glass powder by finely powdering a glass material containing silica (SiO ₂ ) (S100) , Ball milling the fine glass powder (S200), acid treatment of the ball milled fine glass powder (S300), and reducing the silica contained in the acid-treated fine glass powder to prepare a silicon powder It includes a step (S400).

The present invention relates to a method of manufacturing a high-purity silicon powder material using a glass substrate of a waste LCD panel or a glass scrap generated in an LCD panel manufacturing process. As the amount of waste LCD panels increases, methods for manufacturing cement clinker or foam for insulation materials by recycling the waste LCD glass constituting the panel are being developed, but the manufacturing process is complicated and economical is poor, and high capacity lithium Since silicon powder can be used as an anode material of an ion battery, the present invention has been devised to synthesize silicon powder from a waste LCD glass substrate as an economical recycling method.

Specifically, the method of manufacturing a silicon powder material according to the present invention includes a fine glass powder generation step (S100), a ball milling step (S200), an acid treatment step (S400), and a silicon powder synthesis step (S500).

The fine glass powder generation step (S100) is a process of finely powdering a glass material containing silica (SiO ₂ ). Here, the silica-containing glass material may be used by recovering a glass substrate separated from a waste LCD panel or a glass scrap generated in an LCD panel manufacturing process. In the case of the glass used for the LCD panel, since it contains up to 70% of silica as a component, it can be used in the present invention for synthesizing silicon powder using silica as a raw material. However, the glass material of the present invention is not necessarily limited to the glass substrate or glass scrap, and any glass material may be used as long as it is a glass containing a silica component.

Here, the glass material may be pulverized and the pulverized glass material may be sieved to obtain a fine glass powder having a predetermined particle size. At this time, the glass material is mechanically crushed and then undergoes a pulverization process.The crushing and pulverization are determined according to the particle size of the glass material, and the crushing process with a relatively large particle size is first executed, and then the glass material is crushed through the crushing process. Micronize. However, the crushing and pulverizing processes are not clearly distinguished and are continuously performed in the pulverization step. After pulverizing the glass material in this way, a fine glass powder having a predetermined size is sorted using a sieve. At this time, a sieve having a size of #100 to #300 may be used, but the size of the sieve is not limited thereto, and the size of the sieve may be selected in consideration of a subsequent process. Here, the sieve is a generic term for a tool capable of selecting the finely divided glass material by particle size, and is not limited to a specific tool.

When the fine glass powder is obtained, pretreatment to remove impurities from the fine glass powder is performed prior to synthesis of the silicon powder. In addition to silica, LCD glass contains oxides and other components such as aluminum (Al), calcium (Ca), strontium (Sr), boron (B), etc., so other components other than silica are removed as much as possible through pretreatment. Components other than silica are difficult to remove by forming an inert compound after thermal reduction of magnesium to be described later, so pretreatment is important, and a high purity silica precursor can be prepared through this. Here, the pretreatment proceeds to a ball milling step (S200) and an acid treatment step (S300).

The ball milling step (S200) is performed in a manner of pulverizing the material by impact, shear force, friction force, etc. by placing a material in a container containing a ball and rotating the container. The ball milling process for the fine glass powder makes the size of the fine glass powder smaller, so that impurities can be removed as far as possible into the glass particles in the subsequent acid treatment. Also, some impurities may be removed through ball milling. Here, the ball milling may employ a wet ball milling method. Wet ball milling is a method of ball milling in a state in which a liquid diluent such as distilled water is mixed in a rotating container of a ball mill. At this time, there is a difference in the milling effect depending on the rotational speed and the milling time, but it is appropriate to perform wet ball milling at 150 ~ 200 rpm for 24 hours or longer. Here, the longer the milling time, the smaller the particle size and the pretreatment efficiency increases.However, as the processing time increases, the economical efficiency decreases, and since it is possible to synthesize sufficiently high-purity silicon powder, the milling time is about 24 hours. Is suitable. However, the wet ball milling process conditions are not necessarily limited to the rotation speed and the milling time, and may be differently determined in consideration of the amount and state of the fine glass powder to be pretreated, and the subsequent acid treatment process. On the other hand, after wet ball milling, the fine glass powder is dispersed in the dispersion, so the fine glass powder is collected and dried using a filter. In this case, drying may be performed in a freeze drying method. As an example, this process is preferably carried out so that the average particle diameter of the finally obtained particles is 600 nm or less.

After the ball milling step (S200), an acid treatment step (S300) is performed, where the acid solution and the fine glass powder are brought into contact to remove most of the impurities that have not been removed by the ball milling. At this time, as the acid solution, nitric acid (aqueous) solution, hydrochloric acid (aqueous) solution, or the like may be used. In addition, the contact method may be a method of immersing the fine glass powder in an acid solution, and in this case, it may be immersed at 50 to 70°C for 65 to 80 hours. However, the contact method and/or the immersion temperature and time are not necessarily limited to the above. After contacting the acid solution in this way, washing and drying the fine glass powder can be additionally performed. At this time, when the fine glass powder is dispersed in an acid solution, it may be separated using a filter, washed with distilled water or the like as a washing solution, and then freeze-dried. For example, in the acid treatment process, it is appropriate to proceed until the concentration of the aluminum (Al) element, which is an impurity having the highest content, is 2 wt% or less, but is not limited thereto.

The silicon powder synthesis step (S400) is a process of producing silicon powder by reducing silica contained in the fine glass powder. Here, since the fine glass powder has impurities removed through the pretreatment process, high-purity silicon powder can be synthesized.

At this time, in order to synthesize silicon from silica, a magnesium thermal reduction process is performed. Magnesium heat reduction is performed by mixing the pretreated fine glass powder and magnesium powder and then heating it. For example, fine glass powder and magnesium powder are mixed and placed in a boat, the boat is sealed, and the boat is heated in an argon atmosphere using a furnace. In this case, the heating (heating) rate may be 1 to 5°C/min, the reduction temperature may be 600 to 700°C, and the reduction time may be 2 to 6 hours.

When a powder product is obtained by the magnesium thermal reduction process, by-products are removed using hydrochloric acid (HCl) and hydrofluoric acid (HF). For example, the product may be added to an aqueous hydrochloric acid solution for 1 to 2 hours and then filtered through a filter, and the filtered product may be added to an aqueous hydrofluoric acid solution for 1 to 2 hours and then filtered again, washed and dried to synthesize a silicon powder. .

Through the above process, high-purity silicon powder having a silicon (Si) content of 99.0 to 99.9 wt% may be synthesized. In addition to silicon, the high-purity silicon powder may include remaining aluminum (Al) and other inevitable impurities. Other inevitable impurities may include boron (B), calcium (Ca), and strontium (Sr). Since LCD waste glass, such as a glass substrate separated from a waste LCD panel or glass scrap generated in the LCD panel manufacturing process, is made of alkaline earth metal aluminoborosilicate glass, no matter how much silicon is synthesized through the magnesium heat reduction process, ball milling and nitric acid Even after treatment, a small amount of impurity elements may remain, and the impurities may include aluminum (Al), boron (B), calcium (Ca), and strontium (Sr).

The silicon powder prepared in this way can be used to manufacture a lithium ion battery anode. For example, silicon powder prepared according to the present invention, a conductive material, a binder, distilled water, etc., are mixed to form a slurry, and then applied to an electrode member such as a copper foil, and the copper foil coated with the slurry is added to water. After being exposed to a humid environment for a certain period of time, such as immersion in, the anode can be manufactured by drying in an oven. Here, the silicon powder is used as an electrode active material.

Hereinafter, the present invention will be described in more detail through specific examples and evaluation examples.

Example 1: Ball milling / nitric acid treatment-glass powder production

Glass scraps were recovered in the LCD panel manufacturing process, pulverized through a mortar after mechanical crushing, and filtered through a #200 sieve to obtain fine glass powder. 5 g of fine glass powder and 100 mL of distilled water were added to a polypropylene container containing zirconium oxide balls, and a wet ball milling process was performed at a rotational speed of 180 rpm for 24 hours, and the aqueous glass powder solution that had undergone the ball milling process was filtered through a nylon filter. Then, it was lyophilized. Next, a glass bottle containing 5 g of fine glass powder and 100 mL of 5 M nitric acid aqueous solution was maintained at 60° C. for 72 hours, and the ultra-fine glass powder / nitric acid aqueous solution was filtered through a nylon filter, washed with distilled water, and freeze-dried to obtain the final glass powder. Was prepared. The glass powder produced thereby is defined as "ball milling/nitric acid treatment-glass" below.

Example 2: Ball milling / nitric acid treatment-silicon production

Ball milling / nitric acid treatment prepared in Example 1-0.5 g of glass powder and 0.4 g of magnesium were uniformly mixed in a glove box, put in a stainless steel container and sealed, and the stainless steel container was put in a tube furnace, and then in an argon atmosphere. The magnesium thermal reduction process was performed at a heating rate of 5° C./min, a reduction temperature of 650° C., and a reduction time of 6 hours.

The product obtained through the magnesium thermal reduction process was put in 300 mL of 2 M hydrochloric acid aqueous solution for 1 hour and filtered through a nylon filter. The powder filtered through a nylon filter was put in 300 mL of a 5 wt% hydrofluoric acid aqueous solution for 1 hour, then filtered through a nylon filter, and the filtered powder was washed with distilled water and freeze-dried to make silicon powder (hereinafter referred to as "ball milling/nitric acid treatment-silicon"). Ha) obtained.

Example 3: Ball milling / nitric acid treatment-silicon post-treatment electrode manufacturing

The silicon powder prepared in Example 2 (ball milling / nitric acid treatment-silicon) 400 mg, super P conductive material 6 mg, carboxymethyl cellulose 4 mg, citric acid 4.55 mg, potassium hydroxide 0.55 mg, distilled water 125 mg uniformly mixed After preparing the slurry, the slurry was applied to a copper foil. Next, the copper foil coated with the slurry was immersed for 2 days in a container containing a small amount of water (relative humidity: ~ 99%), and then dried in an oven at 60° C. for 12 hours to prepare a silicon electrode (Fig. 5 (a) see). The silicon electrode thus prepared is referred to as "ball milling/nitrate treatment-silicon post treatment electrode".

Comparative Example 1: Preparation of fine glass powder, ball milling-glass powder and nitric acid treatment-glass powder

As in Example 1, the glass scrap was pulverized and sieved through a #200 sieve to prepare fine glass powder (hereinafter, referred to as "fine glass").

In addition, except for nitric acid treatment in Example 1, a glass powder (hereinafter referred to as "ball milling-glass") was prepared by performing a wet ball milling process and freeze-drying on the fine glass powder.

In addition, without going through the bowling process in Example 1, the fine glass powder was treated with an aqueous nitric acid solution, washed and freeze-dried to prepare a glass powder (hereinafter referred to as "nitric acid treatment-glass").

Comparative Example 2: Ball milling-silicon and nitric acid treatment-silicon production

For the ball milling-glass prepared in Comparative Example 1, as in Example 2, heat reduction of magnesium and hydrochloric acid/hydrofluoric acid treatment were performed to prepare silicon powder (hereinafter referred to as “ball milling-silicon”).

In addition, for the nitric acid treatment-glass prepared in Comparative Example 1, silicon powder (hereinafter referred to as "nitric acid treatment-silicon") was prepared according to Example 2 above.

Comparative Example 3: Ball milling / nitric acid treatment-silicon electrode manufacturing

In Example 3, the copper foil coated with the slurry was not immersed in water, but was immediately dried in an oven at 60° C. for 12 hours to prepare a silicon electrode (hereinafter referred to as “ball milling/nitric acid treatment-silicon electrode”).

Evaluation Example 1: Evaluation of physical/chemical properties of glass powder samples

3 is an elemental composition (a), scanning electron microscope (SEM) images (b, d, f, h), and particle size analysis results of glass powder samples prepared according to Example 1 and Comparative Example 1 (c, e, g, i).

For each glass powder prepared in Example 1 and Comparative Example 1, physical/chemical properties were analyzed and compared according to pretreatment conditions, and the results are shown in FIG. 3. Here, the elemental composition analysis of FIG. 3A is based on X-ray fluorescence spectrometer (XRF) data.

First, when comparing the SEM images (b, d, f, h) and the particle size analysis results (c, e, g, i), when ball milling was performed, the particle size was small and the particle size distribution was narrowed. Can be seen.

In addition, referring to the data of FIG. 3 (a), when comparing fine glass and ball milling-glass, it was found that the effect of removing impurities due to ball milling was insufficient. On the other hand, when comparing fine glass and nitric acid treatment-glass, it can be seen that aluminum oxide that was not removed by ball milling was significantly reduced through nitric acid treatment. However, even with nitric acid treatment, there were still many impurities. On the other hand, when comparing the nitric acid treatment-glass and ball milling/nitric acid treatment-glass data, it can be seen that most of the impurities other than silica and oxygen were removed from the ball milling/nitric acid treatment-glass. From this, it can be seen that in the case of nitric acid treatment after reducing the particle size through a ball milling process, impurities are removed as far as possible into the glass particles.

On the other hand, ball milling was performed for 24 hours in Example 1 and Comparative Example 1, the ball milling time was increased to 72 hours, and ball milling/nitric acid treatment-glass and ball milling-glass were prepared in the same manner, and then XRF analysis was performed. I did. The results are shown in [Table 1] below.

Element(oxide)	Concentration(%)
	72h ball milling-glass	72h Ball Milling/Nitric Acid Treatment-Glass
Si	68.86	97.75
Al	15.29	2.25
Sr	5.60	0
Ca	8.62	0

From the above results, it can be seen that the impurity removal efficiency increases as the ball milling time increases. This indicates that the particle size becomes smaller as the ball milling time increases, and impurities are more effectively removed after nitric acid treatment.

Evaluation Example 2: Impurity Analysis of Silicon Powder

4 is an X-ray diffraction (XRD) analysis result (a) of silicon powder samples prepared according to Example 2 and Comparative Example 2, and energy dispersive X-ray spectroscopy (EDS) mapping with scanning electron microscope (SEM) images. This is the image analysis result (b).

Referring to Figure 4 (a), the ball milling of Comparative Example 2-silicon and nitric acid treatment-silicon in addition to the silicon-related peak MgAl ₂ O ₄ , CaB ₆ , SrB ₆ Since the related peak appears, it is understood that MgAl ₂ O ₄ , CaB ₆ , and SrB ₆ impurities exist. In addition, it can be confirmed that the impurities are present through the EDS sheet of FIGS. 4B and 4C.

On the other hand, as shown in FIGS. 4A and 4D, the ball milling/nitric acid treatment-silicon prepared according to Example 2 contains almost no impurities, and impurities are sufficiently removed through ball milling and nitric acid treatment. It can be seen that high-purity silicon powder was prepared through magnesium thermal reduction.

In addition, impurities in the silicon powder synthesized in Example 2 were analyzed through Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The results are shown in Table 2 below.

Element	wt%
Al	0.5
B	0.16
Ca	0.03
Sr	0.04

As a result of the ICP-OES analysis, impurities of the same concentration were detected, and the purity of the ball milling/nitric acid treatment-silicon was calculated as 99.27 wt%.

In addition, components of the silicon powder synthesized in Example 2 were analyzed using TEM-EDX and SEM-EDX. The TEM-EDX analysis results are shown in the following [Table 3], and the SEM-EDX analysis results are shown in the following [Table 4].

Element	wt%	atomic%
Al	0.51	0.53
B	0.00	0.00
Ca	-0.47	-0.33
Sr	0.04	0.01
Si	99.48	99.02

Element	wt%	atomic%
Al	0.35	0.37
B	0.00	0.00
Ca	0.04	0.04
Sr
Si	99.59	99.59

The concentration of boron (B) was not detected with EDX, and the concentration of strontium (Sr) could not be measured in SEM-EDX, but in any case, the silicon (Si) content showed high purity of about 99.5 wt%.

Evaluation Example 3: Evaluation of lithium ion battery anode characteristics

5 is a process chart for manufacturing an electrode according to Example 3 (a), and galvanostatic charge/discharge (b), cyclic voltammetry (c), and rate capability performance (d) of the electrodes manufactured according to Example 3 and Comparative Example 3 ) This is the evaluation result.

Referring to Figure 5 (a), in Example 3 ball milling / nitric acid treatment-electrode post-treatment was performed in order to realize stable capacity characteristics of the silicon electrode. Here, the binder was agglomerated between the silicon particles to improve the cohesive force of the electrode active material. In addition, the adhesion between the electrode active material and the copper foil was improved by forming a copper-ester bond. Accordingly, the mechanical strength of the electrode is improved, and the electrode can maintain its capacity even during continuous charging and discharging. This effect can be confirmed through FIGS. 5(b) to (d) evaluating the performance of the ball milling/nitric acid treatment-silicon post-treatment electrode of Example 3 and the ball milling/nitric acid treatment-silicon electrode of Comparative Example 3. .

5B is an evaluation of capacity stability, the capacity of the ball milling/nitric acid treatment-silicon electrode of Comparative Example 3 decreases rapidly, but in the case of the ball milling/nitric acid treatment-silicon post-treatment electrode of Example 3, high capacity It can be seen that this relatively slowly decreases.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the present invention is not limited thereto, and those of ordinary skill in the art within the spirit of the present invention It is clear that modifications or improvements are possible.

All simple modifications or changes of the present invention belong to the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

According to the present invention, since the LCD waste glass is finely powdered, the fine glass powder is ball-milled and acid-treated to synthesize high-purity silicon powder.

Claims (11)

1. Generating a fine glass powder by finely powdering a glass material containing silica (SiO ₂ );

   Ball milling the fine glass powder;

   Acid-treating the ball milled fine glass powder; And

   Reducing the silica contained in the acid-treated fine glass powder to prepare a silicon powder; silicon powder material manufacturing method comprising a.
2. The method according to claim 1,

   The glass material is a silicon powder material manufacturing method that is a glass substrate separated from a waste LCD panel.
3. The method according to claim 1,

   The glass material is a method of manufacturing a silicon powder material, which is a glass scrap generated in an LCD panel manufacturing process.
4. The method according to claim 1,

   The step of producing the fine glass powder,

   Pulverizing and pulverizing the glass material; And

   Sieve (sieving) the finely divided glass material to select; silicon powder material manufacturing method comprising a.
5. The method according to claim 1,

   The ball milling is a wet ball milling method for producing a silicon powder material.
6. The method according to claim 1,

   The acid treatment is a method of manufacturing a silicon powder material by immersing the fine glass powder in an acid solution.
7. The method of claim 6,

   The acid solution is an aqueous nitric acid solution, a method for producing a silicon powder material.
8. The method of claim 6,

   The fine glass powder is a silicon powder material manufacturing method that is immersed in the acid solution for 65 to 80 hours at 50 ~ 70 ℃.
9. The method according to claim 1,

   Between the acid treatment step and the silica reduction step,

   Washing and freeze-drying the acid-treated fine glass powder; silicon powder material manufacturing method further comprising.
10. The method according to claim 1,

    The silicon powder, silicon (Si) 99.0 ~ 99.9 wt%, remaining aluminum (Al), and a method for producing a silicon powder material containing other inevitable impurities.
11. The method of claim 10,

    The other inevitable impurities include boron (B), calcium (Ca), and strontium (Sr).

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