KR101339957B1 - Silica sand agglomerates for extracting metal grade silicon and menufacturing method thereof - Google Patents

Abstract

The silica sand molding for extracting metal silicon according to the present invention is prepared by mixing clay component, a liquid adhesive, and silica sand having a range of size distribution in a lump form, thereby reducing the reaction in the state of being charged into a carbon reduction furnace maintained at a high temperature. Its shape is maintained during this, providing the effect of smooth heat transfer and gas circulation.

Description

Silica sand agglomerates for extracting metal grade silicon and menufacturing method

The present invention relates to a technique for manufacturing metal silicon from silica sand, and more specifically, a silica sand molding for charging silica sand into the reduction reactor as a pretreatment process for preparing metal silicon by charging the silica sand into a high temperature reduction reactor; It relates to a method for producing the molded article.

Silicon is one of the most widely distributed elements in nature. Silicon is a semimetal element between metal and nonmetal. In nature, silicon exists mainly in the form of silicon oxide and silicate. The first silicon was obtained in 1811 by Kerinochar and Cedar rudder heating the silicon with oxide. The property of silicon was used by Berzelius in 1823 as the name Si. In 1855, Deweili invented crystalline silicon of gray metallic sheen.

High purity silicon was invented by Lion (Dwlyon) through the method of SiCd ₄ + 2Zn = 2ZnCl ₂ + Si. In 1869, when Dmitri Ivanovich Mendeleev raised the periodicity of the element, the atomic number of silicon belonged to the 14th group IV. The carbon reduction method of silicon scaled-up in modern industry was invented in the early 20th century and is less than 100 years old. The silicon content of silicon produced by the carbon reduction method using silica and a carbon reducing agent is referred to as '99 silicon 'as a product of more than 99%, and in the English, it is referred to as' silicon silicon' and 'crystalline silicon' in Russian.

High-purity metal silicon can be produced through a series of refining processes to produce single crystal silicon (99.99% silicon). It is used in the electronics industry and as a key raw material for semiconductors. Currently, high purity 99silicon is used for a wide range of applications, and the demand for 99silicon in domestic and overseas markets is gradually increasing. With the advancement of high-tech technology and the development of the global economy, the range of use of silicon is also getting wider and the demand is gradually increasing.

Prior to the twentieth century, France, the United States, Japan, Italy, and the former Soviet Union subsequently built thousands of kilowatt single- and three-phase electric furnaces and refined metal silicon in the furnace using carbon reduction.

The reduction process of metal silicon by the carbon reduction method is represented by the following formula. That is, metal silicon can be obtained by a reaction such as SiO ₂ + 2C ----> Si + 2CO. Such a reduction reaction is carried out in a high temperature reduction reaction furnace as an endothermic reaction. Such a carbon reduction method is disclosed in Korean Patent Publication No. 2010-0043092 (published: April 27, 2010).

Conventionally, silica is used as a raw material of metal silicon as disclosed in Korean Patent Laid-Open No. 2010-0043092. Generally, the silica is finely crushed and then mixed with necessary raw materials such as activated carbon to be heated to a high temperature in an electric furnace equipped with carbon rods to cause a reduction reaction. By the way, quartz (quartz), which is a raw material of metal silicon, is widely distributed on the earth, but as a result of mining in large quantities since the 60s, the mining conditions are becoming increasingly difficult.

Therefore, related industries are exploring materials other than silica as a raw material of metal silicon. Silica sand contains almost the same ingredients as silica, making it a good substitute for silica. The silica is high in strength and there is no fear of breakage in the carbon reduction process, but the silica is not in the form of agglomerate, so it is difficult to be charged into the carbon reduction furnace. If the silica sand lumps charged in the carbon reduction furnace are damaged, heat transfer or gas circulation is blocked, so that the reduction reaction does not occur properly. Therefore, the silica sand lumps to be charged into the carbon reduction furnace must have sufficient strength.

By the way, silica sand is difficult to form a lump like silica as a sand component. In order to cause the reduction reaction by charging the silica sand in the reduction reactor, it is necessary to form a lump structure like the conventional silica. However, agglomerate structures such as silica are not currently developed using silica sand.

Disclosure of Invention It is an object of the present invention to provide a metal silicon material which can be substituted for silica using sand sand, which is devised to solve the above problems.

In order to achieve the above object, the silica sand molding for extracting metal silicon according to an embodiment of the present invention has a clay component of 3 wt% to 6 wt%, a liquid adhesive of 4 wt% to 9 wt%, and a particle size of 0.03 mm to It is characterized by the fact that it contains silica sand with a distribution of 0.7 mm.

On the other hand, in order to achieve the above object, the metal silica extract silica sand molding according to another embodiment of the present invention, the clay component 12wt% to 18wt%, the liquid adhesive 9wt% to 15wt% and the particle size as the remaining components 0.8 It is characterized in that it includes silica sand having a distribution of mm to 2.3 mm.

On the other hand, in order to achieve the above object, the metal silica extract silica sand molding according to another embodiment of the present invention, the clay component 12wt% to 18wt%, the liquid adhesive 9wt% to 15wt% and the particle size as the remaining components 0.8 It is characterized in that it includes silica sand having a distribution of mm to 2.3 mm.

The liquid adhesive is preferably a mixture of starch powder and water.

As a method of manufacturing the silica sand molding for metal silicon extraction,

A mixing step of mixing the clay component, the liquid adhesive, and the silica sand;

A pressurizing step of increasing density by applying pressure to the mixture formed in the mixing step to reduce pores;

Forming step of producing a mixture of a predetermined size of the mixture passed through the pressing step; And

Characterized in that it comprises a; drying step of drying the mass structure formed in the forming step.

The form of the lump formed in the forming step is preferably any one of spherical, cylindrical, briquettes, gravel form.

The apparent density of the mass structure formed after the drying step is preferably 85% to 98%.

The drying method used in the drying step is preferably any one of heat drying, blowing drying, natural drying.

The silica sand molding for extracting metal silicon according to the present invention and a method of manufacturing the molded article can be manufactured using metal sand using sand sand, which is readily available on the earth, instead of silica, thereby securing raw materials at an economic cost and providing natural Provide the effect of protecting the environment.

1 is a table showing the components of the silica sand molding for metal silicon extraction according to the present invention.
Figure 2 is a process chart of a method for producing a silica sand molding for metal silicon extraction according to the present invention.
3 is a photograph of a silica sand molding for metal silicon extraction according to the present invention.
4 is a photograph of a state in which the silica sand molding for metal silicon extraction shown in FIG. 3 is loaded in a carbon reduction furnace.
Figure 5 is a photograph showing the form after the silicon silica extract for silicon silicon extraction shown in Figure 4 is heated to 1300 ℃ and cooled to room temperature.

Hereinafter, preferred embodiments of the present invention will be described in detail.

1 is a table showing the components of the silica sand molding for metal silicon extraction according to the present invention. Figure 2 is a process chart of a method for producing a silica sand molding for metal silicon extraction according to the present invention. 3 is a photograph of a silica sand molding for metal silicon extraction according to the present invention. 4 is a photograph of a state in which the silica sand molding for metal silicon extraction shown in FIG. 3 is loaded in a carbon reduction furnace. Figure 5 is a photograph showing the form after the silicon silica extract for silicon silicon extraction shown in Figure 4 is heated to 1300 ℃ and cooled to room temperature.

≪ Embodiment 1 >

According to the first embodiment of the present invention, the metal silicon extraction silica sand molding is a silica component having a distribution of 3wt% to 6wt% of clay component, 4wt% to 9wt% of liquid adhesive and a particle size of 0.03mm to 0.7mm as the remaining components. It includes.

The clay component is mixed to maintain the bond between the silica sand particles during the reduction reaction of the molding charged in the carbon reduction furnace. The weight of the clay component varies depending on the size of the silica sand particles. The clay component may be, for example, kaolin, loess and the like used to manufacture ceramics. In the present embodiment, when the content of the clay component is less than 3wt%, when the molding is reduced in the carbon reduction furnace, the bonding force between the silica sand is so weak that the molding is broken and powdered at an early stage so that heat transfer is not performed properly around the silica sand particles. Without the proper circulation of the reducing gas there is a problem that can not properly obtain the metal silicon. When the content of the clay component exceeds 6wt%, the molded product maintains sufficient strength when the reduction reaction occurs in the carbon reduction furnace, but the amount of metal silicon is reduced in the molded product by mixing more clay components than necessary, thereby reducing the amount of metal silicon. There is a problem that the quantity is small. The clay component used in the present invention is, in a broad sense, a kaolinite mineral such as kaolinite, dickite, halloysite, montmorillonite, bentonite, bentonite, and the like as kaolinite, dickite, and halloysite. Acid clay, and kaolin, refractory clay, and the like. Among them, it is preferred that the kaolin (whiteness _{Sat, Al 2 O 3 · 2SiO 2} · 2H 2 O) component using a number of clay component. In the present embodiment, the clay component used was 70% or more kaolin content. The clay component may be employed that contains about 30% to 99% kaolin content.

In the present embodiment, the liquid adhesive used starch paste mixed with starch powder and water. The starch paste may be used for example starch paste commonly available on the market. Generally, starch paste may be prepared by adding 40 wt% to 80 wt% of water to 100 wt% of starch powder.

When the liquid adhesive is contained in less than 4wt% there is a problem that can not maintain sufficient hardness because the silica sand and clay is not properly bonded at room temperature. On the other hand, when the liquid adhesive is more than 9wt% there is a problem in that the molded product can not maintain the shape by flowing down because the viscosity of the mixture is too small in the state that the silica sand and clay combined at room temperature.

The silica sand is a mineral serving as a raw material of metal silicon. Generally, sand sand may be used as the silica sand. Particles of the silica sand may be variously distributed according to the weathering degree of the silica sand. In the present embodiment, the silica sand particles are limited to 0.03 mm to 0.7 mm. Depending on the size of the silica sand particles, the content of the clay component added and the content of the liquid adhesive will be different. Therefore, the size of the silica sand particles to be limited to 0.03mm to 0.7mm as in this embodiment is determined by the content of the clay component to be mixed and the content of the liquid adhesive.

≪ Embodiment 2 >

According to the second embodiment of the present invention, the silica sand molding for metal silicon extraction is a silica component of 7wt% to 9wt%, the liquid adhesive 6wt% to 12wt% and the other components of the silica sand having a particle size distribution of 0.6mm to 1.1mm It includes.

The clay component is mixed to maintain the bond between the silica sand particles during the reduction reaction of the molding charged in the carbon reduction furnace. The weight of the clay component varies depending on the size of the silica sand particles. The clay component may be, for example, kaolin, loess and the like used to manufacture ceramics. In the present embodiment, when the content of the clay component is less than 7wt%, when the molding is reduced in the carbon reduction furnace, the bonding force between the silica sand is too weak, so that the molding is broken and powdered prematurely so that heat transfer is not performed properly around the silica sand particles. Without the proper circulation of the reducing gas there is a problem that can not properly obtain the metal silicon. When the content of the clay component exceeds 9wt%, the molding maintains sufficient strength when the reduction reaction occurs in the carbon reduction furnace, but the amount of metal silicon in the molding decreases due to the mixing of more clay components than necessary. There is a problem that the quantity is small. In the present embodiment, the liquid adhesive used starch paste mixed with starch powder and water. Detailed information on the clay component will be referred to the description of the first embodiment.

The starch paste may be used for example starch paste commonly available on the market. Generally, starch paste may be prepared by adding 40 wt% to 80 wt% of water to 100 wt% of starch powder.

When the liquid adhesive is contained in less than 6wt% there is a problem that can not maintain sufficient hardness because the silica sand and clay is not properly bonded at room temperature. On the other hand, when the liquid adhesive is more than 12wt% there is a problem in that the molded product can not maintain the form by flowing down because the viscosity of the mixture is too small in the state that the silica sand and clay combined at room temperature.

The silica sand is a mineral serving as a raw material of metal silicon. Generally, sand sand may be used as the silica sand. Particles of the silica sand may be variously distributed according to the weathering degree of the silica sand. In this embodiment, the silica sand particles are limited to 0.6 mm to 1.1 mm. Depending on the size of the silica sand particles, the content of the clay component added and the content of the liquid adhesive will be different. Therefore, limiting the size of the silica sand particles to 0.6mm to 1.1mm as in this embodiment is determined by the content of the clay component to be mixed and the content of the liquid adhesive.

≪ Third Embodiment >

According to the third embodiment of the present invention, the metal silicon extraction silica sand molding is a silica component of 12wt% to 18wt%, the liquid adhesive 9wt% to 15wt% and the other components of the silica sand having a particle size distribution of 0.8mm to 2.3mm It includes.

The clay component is mixed to maintain the bond between the silica sand particles during the reduction reaction of the molding charged in the carbon reduction furnace. The weight of the clay component varies depending on the size of the silica sand particles. The clay component may be, for example, kaolin, loess and the like used to manufacture ceramics. In the present embodiment, if the content of the clay component is less than 12wt%, when the molding is reduced in the carbon reduction furnace, the bonding strength between the silica sand is too weak, so that the molding is broken and powdered prematurely so that heat transfer is not performed properly around the silica sand particles. Without the proper circulation of the reducing gas there is a problem that can not properly obtain the metal silicon. When the content of the clay component exceeds 18wt%, the molding maintains sufficient strength when the reduction reaction occurs in the carbon reduction furnace, but the amount of metal silicon in the molding decreases due to the mixing of more clay components than necessary. There is a problem that the quantity is small. Detailed information on the clay component will be referred to the description of the first embodiment.

In the present embodiment, the liquid adhesive used starch paste mixed with starch powder and water. The starch paste may be used for example starch paste commonly available on the market. Generally, starch paste may be prepared by adding 40 wt% to 80 wt% of water to 100 wt% of starch powder.

When the liquid adhesive is contained in less than 9wt% there is a problem that can not maintain sufficient hardness because silica and clay is not properly bonded at room temperature. On the other hand, if the liquid adhesive is more than 15wt% there is a problem that the molded product can not maintain the shape by flowing down due to the viscosity of the mixture is too small in the state that the silica sand and clay combined at room temperature.

The silica sand is a mineral serving as a raw material of metal silicon. Generally, sand sand may be used as the silica sand. Particles of the silica sand may be variously distributed according to the weathering degree of the silica sand. In the present embodiment, the silica sand particles are limited to 0.8 mm to 2.3 mm. The content of the clay component added and the content of the liquid adhesive are changed depending on the size of the silica sand particles. Therefore, the size of the silica sand particles to be limited to 0.8mm to 2.3mm as in this embodiment is determined by the content of the clay component to be mixed and the content of the liquid adhesive.

Now, a manufacturing method of the silica sand molding for metal silicon extraction composed of such components will be described.

The manufacturing method of the silica sand molding for metal silicon extraction according to the present invention includes a mixing step (S1), a pressing step (S2), a forming step (S3), a drying step (S4).

In the mixing step (S1), the clay component and the liquid adhesive and silica sand are mixed at a ratio of the content as described above. Mixing in the mixing step (S1) may be performed using a stirrer. Mixing in the mixing step (S1) is preferably made at room temperature. The stirring time in the mixing step (S1) is preferably about 3 to 10 minutes.

In the pressing step (S2) is applied to the mixture formed in the mixing step (S1) to reduce the pores. The pressing step (S2) charges the mixture into a cylindrical mold and pressurizes with a press such as a piston to reduce the pores present in the mixture. In general, it is practically impossible to completely remove the pores in the pressing step (S2). In the forming step (S3) to produce a mixture of the pressing step (S2) into a lump of a constant size. The shape of the mass produced in the forming step (S3) may be, for example, spherical, cylindrical, briquettes, gravel form.

In the drying step (S4) to dry the lump structure formed in the molding step (S3). As the drying method in the drying step (S4), for example, various methods such as heat drying, blowing drying, and natural drying may be employed. After passing through the drying step (S4) the apparent density of the molded product was to be 85% to 95%. The apparent density is a percentage based on the surface area of the moldings as a denominator and the molecular weight of the pores distributed on the surface of the moldings. When the apparent density of the molded article is less than 85%, when the molded article is heated to a high temperature in a carbon reduction furnace, pores are expanded to break the molded article. If the apparent density of the molding exceeds 98%, there is no problem in reality, but the pressure applied in the pressing step (S2) is too large, which may damage the press device or cause an accident. When the drying step (S4) is carried out in a natural drying method, when the diameter of the molding is about 5cm to 8cm, the drying time is preferably about 24 hours to 48 hours. When the heat drying method is applied in the drying step (S4), the drying time can be shortened as compared to natural drying.

The silica sand molding for metal silicon extraction manufactured by such a component and manufacturing method is economical because sand silicon of sand can be produced by using sand sand which is easily available on earth instead of silica. It provides the cost of securing raw materials and protecting the natural environment. As a result of the test, it can be seen that the silica sand molded product can be a good material to replace the silica by maintaining its form even at a temperature of 1300 ° C. higher than the reduction reaction temperature of the carbon reduction furnace.

As described above, the silica sand molding for extracting metal silicon and the method of manufacturing the molding according to the present invention enable the production of metal silicon using sand sand in the form of sand which can be easily obtained on earth instead of silica. It secures and protects the natural environment.

The present invention has been described above with reference to preferred embodiments, but the present invention is not limited to the examples, and various forms of embodiments may be embodied without departing from the technical spirit of the present invention.

S1: Mixing Step S2: Pressing Step
S3: forming step S4: drying step

Claims (8)

3 to 6 wt% of clay component, 4 to 9 wt% of liquid adhesive and silica sand having a distribution of 0.03 mm to 0.7 mm in particle size as the remaining components. 7 to 9 wt% of clay component, 6 to 12 wt% of liquid adhesive, and silica sand having a particle size of 0.6 mm to 1.1 mm as a remaining component. 12 to 18 wt% of clay component, 9 to 15 wt% of liquid adhesive and silica sand having a distribution of particle size of 0.8 mm to 2.3 mm as the remaining components. 4. The method according to any one of claims 1 to 3,
The liquid adhesive is methane silicon extract silica sand molding, characterized in that the mixture of starch powder and water. As a method of manufacturing a silica sand molding for metal silicon extraction according to any one of claims 1 to 3,
A mixing step of mixing the clay component, the liquid adhesive, and the silica sand;
A pressurizing step of increasing density by applying pressure to the mixture formed in the mixing step to reduce pores;
Forming step of producing a mixture of a predetermined size of the mixture passed through the pressing step; And
And a drying step of drying the lump structure formed in the forming step. The method of claim 5,
Form of agglomerates formed in the forming step is a method of producing a silica sand molding for metal silicon extraction, characterized in that any one of spherical, cylindrical, briquette, gravel form. delete The method of claim 5,
The drying method used in the drying step is a method for producing a silica sand molded article for metal silicon extraction, characterized in that any one of heat drying, blowing drying, natural drying is employed.

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