Silica Manufacturing System

Abstract

To provide a silica production method which produces silica with high purity by removing impurities and can shorten production time, and cosmetics containing silica having a particle shape and size adjusted to suit the characteristics of cosmetics.SOLUTION: The method for producing silica includes a grinding step (S41) of grinding a vegetable raw material (9), a washing step (S42) of washing the vegetable raw material obtained in the grinding step with water, a dehydration step (S43) of storing the vegetable raw material in a mesh-like dehydration container 15 after the washing step and rotating it with a rotary dehydrator to remove water contained in the vegetable raw material, a firing step (S44) of firing the vegetable raw material, and a fine grinding step (S45) of finely grinding the silica obtained in the firing step.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for efficiently producing silica from plant raw materials. [Background technology]

[0002] Conventionally, silica as fine silicon dioxide has a lower water absorption rate than general powders. This is used to prevent cosmetics such as eye shadow and foundation from solidifying due to moisture, and is also used in creams and milky lotions for stabilization purposes. Silicon dioxide has also been used as an anode material for battery materials that use high-purity silicon.

[0003] Of these types of silica, crystalline silica is known to be a harmful substance, but amorphous silica is not designated as a harmful substance and can be used in cosmetics, food (including supplements), building materials, and agricultural fertilizer and feed (for livestock and pets).

[0004] For example, Patent Document 1 describes rice husk charcoal or rice straw charcoal rich in amorphous silica, which is carbonized by a carbonization device in which rice husks or rice straw are carbonized while being stirred in an oxygen-free atmosphere, and the temperature range at which the rice husks or rice straw are carbonized by the carbonization device is 500°C to 700°C.

[0005] Further, the present invention includes a method for producing amorphous silica, which comprises stirring the rice husk charcoal or rice straw charcoal with ion-exchanged water at a temperature in the range of 30 to 100°C, and dissolving and extracting the amorphous silica contained in the rice husk charcoal or rice straw charcoal in the ion-exchanged water. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-181144 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0007] However, in conventional manufacturing methods, it is necessary to burn organic matter such as cellulose to extract amorphous silica, but it is difficult to increase the purity because metal ions remain as impurities contained in plants. In addition, the longer the manufacturing process takes, the higher the cost becomes, so it is necessary to mass-produce it using a manufacturing method that is as short and cost-effective as possible. In addition, there is a growing demand for silica to replace resin microbeads, and as a result, there has been active development of silica suited to cosmetic applications such as foundations and emulsions.

[0008] The present invention has been made to solve the above problems, and provides an apparatus for producing silica with high purity or whiteness by removing impurities and capable of shortening production time, a method for producing silica, and a cosmetic product containing silica whose particle shape and size have been adjusted to suit the characteristics of the cosmetic product. [Means for solving the problem]

[0009] A soaking step of soaking the plant raw material in an acid solution; a washing step of immersing the plant-based raw material in water, stirring and rinsing the plant-based raw material; a dehydration step in which the plant-based raw material is placed in a dehydration container after the soaking step, and rotated by a rotary dehydration device to remove water contained in the plant-based raw material; A baking step of baking the plant-based raw material obtained from the dehydration step; The present invention is characterized by comprising: Effect of the Invention

[0010] Due to the above characteristics, the time required for drying, which was previously required when soaking in a solution or washing with water, is shortened, improving production efficiency, while at the same time promoting the decomposition of cellulose and the like, and making it possible to remove impurities. Furthermore, it is possible to produce silica with an increased degree of pure whiteness that is optimal for use as a cosmetic material. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a process flow diagram showing the manufacturing steps for producing silica shown in Example 1 of the embodiment. [Diagram 2] FIG. 2 is a process flow diagram showing the manufacturing steps for producing silica shown in Example 2 of the embodiment. [Diagram 3] FIG. 2 is a process flow diagram showing the manufacturing steps for producing silica shown in Example 3 of the embodiment. [Figure 4] FIG. 1 is a process flow diagram showing the manufacturing steps for producing silica shown in Example 4 of the embodiment. [Diagram 5] FIG. 1 is a process flow diagram showing the manufacturing steps for producing silica shown in Example 5 of the embodiment. [Figure 6] FIG. 2 is a distribution diagram showing the time and temperature of the manufacturing process for producing silica according to the embodiment. [Figure 7] 1 is a micrograph showing the particle size of silica according to an embodiment. [Figure 8] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 9] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 10] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 11] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 12] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 13] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 14] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 15] FIG. 1 is a schematic diagram showing test data of a cosmetic product containing silica according to an embodiment. [Figure 16] FIG. 1 is a schematic diagram showing a production apparatus for producing silica according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The method for producing silica according to the present invention and the cosmetic product containing silica obtained by the method will be described in detail with reference to the drawings. Note that the following embodiments and drawings are only examples of some of the embodiments of the present invention, and are not intended to be limited to these configurations, and may be modified as appropriate within the scope of the present invention.

[0013] <Plant-based raw materials> The following describes the plant-based raw material 9, which is a biomass material for producing the silica 10 of Example 1 or Example 2. The present invention produces amorphous silica, which is the final product, by using food residues or discarded plant-based raw material 9. Plants, wood, etc. are used as the plant-based raw material 9, but it is possible to obtain the raw material at low cost by using discarded plant-based raw material 9, such as residues from harvesting plants, as the raw material. [Table 1]

[0014] Table 1 is a composition table of plant-based raw materials 9. In Table 1, the percentages of the components that make up the raw materials shown on the far left are shown on the right. For example, rice straw has 37.4% carbon (C), 0.53% nitrogen (N), 0.06% phosphorus (P), 0.14% phosphoric acid (P2O5), 1.75% potassium (K), 2.11% potash (K2O), 0.05% calcium (Ca), 0.19% magnesium (Mg), and 0.11% sodium (Na).

[0015] Here, the plant-derived silicon-containing porous plant-based raw material 9 can be calcined at a low temperature (600° C. or higher and 800° C. or lower) to extract amorphous silica. Many plant-based raw materials 9 have a structure in which cells are regularly arranged along the axis, and silicic acid is deposited on the cell walls to thicken them.

[0016] Between the rows of silicified cells there are rows of compressed narrow cells, and by removing the charcoal after carbonization it is possible to obtain silica with a high specific surface area. As mentioned above, the plant-based raw material 9 is preferably one that contains a large amount of silicic acid, 13% or more and 35% or less.

[0017] Examples of plant-based raw materials9 that are relatively rich in silicon are shown in Table 1, and include, in addition to rice straw, wheat straw, barley straw, rice bran, rice husks, buckwheat straw, soybean straw, sweet potato vines, turnip leaves, carrot leaves, corn stalks, sugarcane tops, coconut shells, barley husks, cocoa shells, cocoa pods, peanut shells, tangerine peels, red cedar sawdust, larch bark, and fallen ginkgo leaves. In addition, plants themselves may be used instead of residues.

[0018] For example, bamboo is composed of cellulose, hemicellulose, and lignin as cellulose, and minerals such as iron, magnesium, calcium, manganese, copper, and nickel. When bamboo or bamboo leaves are burned, silanol groups (Si-OH) are extracted, and during the burning process, they are extracted as SiO4.

[0019] [Table 2] [Table 3]

[0020] Tables 2 and 3 are composition tables of rice husk, which is the plant raw material 9 most suitable for the method of producing silica among the plant raw materials 9 in Table 1 described above in the present invention. Table 2 shows the ratio of components constituting the raw material in percentage. For example, moisture is 8% to 10%, ash is 10% to 15%, lipids are 0.1% to 0.5%, lignin is 18% to 25%, hemicellulose is 16% to 20%, cellulose is 30% to 35%, and others are 5% to 10%. Thus, the main components of the organic matter that becomes the carbonized material are lignin, hemicellulose, and cellulose.

[0021] Table 3 shows the chemical composition of the inorganic matter of the plant-based raw material 9 shown in Table 2. The plant-based raw material 9 shown in Table 2 is 80 wt% organic matter such as cellulose, and 20 wt% inorganic matter. The chemical composition of the inorganic matter in Table 3 is 92.14 wt% SiO2, 0.04 wt% Al2O3, 0.48 wt% CaO, 0.03 wt% Fe2O3, 3.2 wt% K2O, 0.16 wt% MgO, 0.18 wt% MnO, and 0.09 wt% Na2O. The plant-based raw material 9 such as rice husks shown in Table 2 contains a large amount of silicon dioxide (SiO2) in the inorganic matter.

[0022] In the following, Examples 1 to 5 of this embodiment will be described with reference to a method for producing silica using rice husk, which is one of the plant-derived raw materials 9. Example 1 In Example 1, rice husks, which are one of the plant raw materials 9 of the present embodiment, are used to produce silica, and a method for producing silica will be described with reference to FIG.

[0023] The vegetable raw material 9 is pulverized (S1), but since the fine particles are produced in the fine pulverization step (S5), it is sufficient to pulverize the raw material to the extent that the acid soaks into the interior of the raw material, and since the raw material will go through the dehydration and drying step (S3), it is sufficient that the raw material is pulverized to a size that does not slip through the mesh of the dehydration container 15. The best size after pulverization is about 5 mm to 10 mm. Here, the pulverization method may be a mill, mixer, grinder, or the like.

[0024] Next, the crushed plant-based raw material 9 (S1) is immersed in an acid solution (S2). Examples of the acid solution include sulfuric acid, hydrochloric acid, citric acid, oxalic acid, malic acid, and formic acid. For example, the citric acid solution is a solution in which citric acid is dissolved in pure water at 1% to 10% by weight (S2). After immersion for about a day, a cleaning process is performed to wash away the organic acid and eluted impurities with pure water or the like. The temperature of the aqueous organic acid solution, including citric acid, is preferably 20°C to 80°C.

[0025] Next, the plant-based raw material 9 soaked in acid is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S3). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0026] Dehydration allows impurities to be discharged along with the water. In particular, when citric acid is used, the citric acid sequester metal ions, which are discharged to the outside together with the citric acid solution as metal chelate compounds (metal complexes). Therefore, dehydration improves the purity of the silica itself after firing. Next, drying can be done using a dryer, drying in the sun, or natural drying.

[0027] Next, in the firing process (S4), as shown in FIG. 6, the plant-based raw material 9 is placed in a furnace, the pressure inside the furnace is brought to atmospheric pressure so that oxygen can be supplied, the temperature inside the furnace is raised to 300°C, and the temperature (a) is maintained at 300°C for a certain period of time, about 1 to 3 hours.

[0028] Thereafter, the furnace is made ready for oxygen supply, the temperature inside the furnace is raised to 500°C, and the temperature (b) is maintained at 500°C for a fixed period of time of about 1 to 3 hours.

[0029] After that, oxygen is supplied, the temperature inside the furnace is raised to 700°C, and the temperature is maintained at 700°C for a certain period of time (c), about 1 to 3 hours. After the period of maintaining (c), the rice husks are naturally burned, and the total burning time is set to one day. The best burning time for (c) is 10 to 13 hours.

[0030] After that, the fire naturally goes out, and the fired silica 10 is taken out of the furnace. After the retention time of (c), the rice husks are fired by self-sintering, so there is no need to use energy after the retention time of (c), which reduces costs. By maintaining the temperatures of 300°C and 500°C, which require the most energy when firing rice husks, for a certain period of time, the rice husks can be completely fired, improving their purity.

[0031] The following is an example of the composition of silica 10 after firing. Silica (SiO2) 10 is 99.1 to 99.2%, with other contents including Fe2O3 0.15 to 0.20%, Al2O3 0.05 to 0.03%, K2O 0.05 to 0.08%, CaO 0.2 to 0.5%, and MgO 0.02 to 0.065%.

[0032] Next, the silica 10 is pulverized (S5). The pulverized silica 10 has a particle size distribution ranging from 5 to 20 μm. The pulverization method may be a jet mill, a ball mill, a bead mill, or the like.

[0033] Next, melting and spheroidizing is performed (S6). In the thermal spraying method using plasma or gas, crushed silica powder is fed into a high-temperature flame of 2000°C or more to melt the silica, and the silica melt that has been spheroidized by surface tension is rapidly cooled to obtain spherical silica particles. Because the molten silica is rapidly cooled, the obtained spherical silica particles are amorphous.

[0034] Alternatively, the silica 10 may be spheroidized by a molten flame method, and the temperature of the flame treatment is 1750° C. to 2500° C. As another spheroidization method, spheroidization by spray drying may also be used. In plasma melting, a large volume of thermal plasma is generated and melted at a high temperature exceeding 10,000° C. by a high frequency induction plasma method, whereby a powder of spherical silica 10 with high sphericity can be produced. And what is finally produced is amorphous spherical silica particles 11 (S7).

[0035] Example 2 In Example 2, a method for producing silica using rice husks, which are one of the plant raw materials 9 of this embodiment, will be described with reference to FIG.

[0036] The vegetable raw material 9 is pulverized (S11), but since the fine particles are produced in the fine pulverization step (S15), the pulverization step is sufficient to allow the acid to penetrate the inside of the acid immersion, and the particles should be small enough not to slip through the mesh of the dehydration container 15 during dehydration and drying. The size after pulverization is best about 5 mm to 10 mm. Here, the pulverization method can be a mill, mixer, grinder, etc.

[0037] Next, in the firing step (S12), as shown in FIG. 6, the plant-based raw material 9 is placed in a furnace, the pressure inside the furnace is adjusted to atmospheric pressure so that oxygen can be supplied, the temperature inside the furnace is increased to 300°C, and the temperature (a) is maintained at 300°C for a certain period of time, about 1 to 3 hours.

[0038] Thereafter, the furnace is made ready for oxygen supply, the temperature inside the furnace is raised to 500°C, and the temperature (b) is maintained at 500°C for a fixed period of time of about 1 to 3 hours.

[0039] After that, oxygen is supplied, the temperature inside the furnace is raised to 700°C, and the temperature is maintained at 700°C for a certain period of time (c), about 1 to 3 hours. After the period of maintaining (c), the rice husks are naturally burned, and the total burning time is set to one day. The best burning time for (c) is 10 to 13 hours.

[0040] After that, the fire naturally goes out, and the fired silica 10 is taken out of the furnace. After the retention time of (c), the rice husks are fired by self-sintering, so there is no need to use energy after the retention time of (c), which reduces costs. By maintaining the temperatures of 300°C and 500°C, which require the most energy when firing rice husks, for a certain period of time, the rice husks can be completely fired, improving their purity.

[0041] Next, the fired silica 10 is immersed in an alkaline solution of pH 8 to 11 (S13). The alkaline solution is a solution of sodium bicarbonate, sodium percarbonate, sodium carbonate, or the like dissolved in pure water to a concentration of 1% to 10%, and the liquid temperature is preferably 20° C. to 80° C., and the silica 10 is immersed in the solution for about 2 hours (S13).

[0042] Next, the fired silica 10 is immersed in an acid solution to neutralize it (S14). Examples of the acid solution include sulfuric acid, hydrochloric acid, citric acid, oxalic acid, malic acid, and formic acid. For example, the citric acid solution is a solution in which citric acid is dissolved in pure water at 1% to 10% by weight. After immersion for about one day, a cleaning process is performed to wash away the organic acid and eluted impurities with pure water or the like. The liquid temperature of the aqueous organic acid solution, including citric acid, is preferably 20°C to 80°C. After that, the above-mentioned dehydration and drying process (S3) may be performed.

[0043] The plant-derived raw material 9 soaked in acid is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S3). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0044] Dehydration allows impurities to be discharged along with the water. In particular, when citric acid is used, the citric acid sequester metal ions, which are discharged to the outside together with the citric acid solution as metal chelate compounds (metal complexes). Therefore, dehydration improves the purity of the silica itself after firing. Next, drying can be done using a dryer, drying in the sun, or natural drying.

[0045] Next, the silica 10 is pulverized in the same manner as in S5 described above (S15). The pulverized silica 10 has a large particle size distribution in the range of 5 to 20 μm. The pulverization method may be a pulverization method such as a jet mill, a ball mill, or a bead mill.

[0046] Next, melting and spheroidizing is performed in the same manner as in S6 described above (S16). In the plasma or gas thermal spraying method, crushed silica powder is fed into a high-temperature flame of 2000°C or higher to melt the silica, and the silica melt that has been spheroidized by surface tension is rapidly cooled to obtain spherical silica particles. Because the molten silica is rapidly cooled, the obtained spherical silica particles are amorphous.

[0047] Alternatively, the silica 10 may be spheroidized by a molten flame method, and the temperature of the flame treatment is 1750° C. to 2500° C. As another spheroidization method, spheroidization by spray drying may also be used.

[0048] In addition, in plasma melting, a large volume of thermal plasma is generated and melted at a high temperature exceeding 10,000° C. by a high frequency induction plasma method, making it possible to produce spherical powder of silica 10 with high sphericity. And what is finally produced is amorphous spherical silica particles 11 (S17).

[0049] Example 3 In Example 3, a method for producing silica using rice husks, which are one of the plant raw materials 9 of this embodiment, will be described with reference to FIG.

[0050] The vegetable raw material 9 is pulverized (S21), but since the fine particles are produced in the fine pulverization step (S26), the pulverization step is sufficient to allow the acid to penetrate the inside of the plant when immersed in acid, and the particles should be small enough not to slip through the mesh of the dehydration vessel 15 during dehydration and drying. The size of the pulverized particles is preferably about 5 mm to 10 mm. Examples of the pulverization method include a mill, a mixer, a grinder, etc.

[0051] Next, the steam decomposition step (S22) is a method of decomposing the pulverized plant-based raw material 9 by applying steam. This is a step that particularly promotes the decomposition of lignin and the like, thereby improving purity and burning efficiency. The water vapor may be pure water or the above-mentioned citric acid solution, and a solution of 1% to 10% by weight of citric acid dissolved in pure water is steamed. In the case of steam, the solution is more likely to permeate into the inside of the plant-derived raw material 9, so the steam is applied for about 1 to 5 hours. After that, the above-mentioned dehydration and drying process (S3) may be performed.

[0052] The plant-derived raw material 9 soaked in acid is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S3). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0053] Dehydration allows impurities to be discharged along with the water. In particular, when citric acid is used, the citric acid sequester metal ions, which are discharged to the outside together with the citric acid solution as metal chelate compounds (metal complexes). Therefore, dehydration improves the purity of the silica itself after firing. Next, drying can be done using a dryer, drying in the sun, or natural drying.

[0054] Next, in the firing step (S23), as shown in FIG. 6, the plant-based raw material 9 is placed in a furnace, the pressure inside the furnace is brought to atmospheric pressure so that oxygen can be supplied, the temperature inside the furnace is raised to 300°C, and the temperature (a) is maintained at 300°C for a certain period of time, about 1 to 3 hours.

[0055] Thereafter, the furnace is made ready for oxygen supply, the temperature inside the furnace is raised to 500°C, and the temperature (b) is maintained at 500°C for a fixed period of time of about 1 to 3 hours.

[0056] After that, oxygen is supplied, the temperature inside the furnace is raised to 700°C, and the temperature is maintained at 700°C for a certain period of time (c), about 1 to 3 hours. After the period of maintaining (c), the rice husks are naturally burned, and the total burning time is set to one day. The best burning time for (c) is 10 to 13 hours.

[0057] After that, the fire naturally goes out, and the fired silica 10 is taken out of the furnace. After the retention time of (c), the rice husks are fired by self-sintering, so there is no need to use energy after the retention time of (c), which reduces costs. By maintaining the temperatures of 300°C and 500°C, which require the most energy when firing rice husks, for a certain period of time, the rice husks can be completely fired, improving their purity.

[0058] Next, the fired silica 10 is immersed in an alkaline solution of pH 8 to 11 (S24). The alkaline solution is a solution of sodium bicarbonate, sodium percarbonate, sodium carbonate, or the like dissolved in pure water to a concentration of 1% to 10%, and the liquid temperature is preferably 20° C. to 80° C., and the silica 10 is immersed in the solution for about 2 hours (S24).

[0059] Next, the silica 10 is immersed in an acid solution to neutralize it (S25). Examples of the acid solution include sulfuric acid, hydrochloric acid, citric acid, oxalic acid, malic acid, and formic acid. For example, the citric acid solution is a solution in which citric acid is dissolved in pure water at 1% to 10% by weight. After immersion for about one day, a cleaning process is performed to wash away the organic acid and eluted impurities with pure water or the like. The liquid temperature of the aqueous organic acid solution, including citric acid, is preferably 20°C to 80°C. After that, the above-mentioned dehydration and drying process (S3) may be performed.

[0060] The plant-derived raw material 9 soaked in acid is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S3). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0061] Dehydration allows impurities to be discharged along with the water. In particular, when citric acid is used, the citric acid sequester metal ions, which are discharged to the outside together with the citric acid solution as metal chelate compounds (metal complexes). Therefore, dehydration improves the purity of the silica itself after firing. Next, drying can be done using a dryer, drying in the sun, or natural drying.

[0062] Next, the silica 10 is pulverized in the same manner as in S5 described above (S26). The pulverized silica 10 has a large particle size distribution in the range of 5 to 20 μm. The pulverization method may be a pulverization method such as a jet mill, a ball mill, or a bead mill.

[0063] Next, melting and spheroidizing is performed in the same manner as in S6 described above (S27). In the thermal spraying method using plasma or gas, crushed silica powder is fed into a high-temperature flame of 2000°C or higher to melt the silica, and the silica melt that has been spheroidized by surface tension is rapidly cooled to obtain spherical silica particles. Because the molten silica is rapidly cooled, the obtained spherical silica particles are amorphous.

[0064] Alternatively, the silica 10 may be spheroidized by a molten flame method, and the temperature of the flame treatment is 1750° C. to 2500° C. As another spheroidization method, spheroidization by spray drying may also be used.

[0065] In addition, in plasma melting, a large volume of thermal plasma is generated and melted at a high temperature exceeding 10,000° C. by a high frequency induction plasma method, making it possible to produce spherical powder of silica 10 with high sphericity. And what is finally produced is amorphous spherical silica particles 11 (S28).

[0066] Example 4 In Example 4, a method for producing silica using rice husks, which are one of the plant raw materials 9 of this embodiment, will be described with reference to FIG.

[0067] The vegetable raw material 9 is pulverized (S31), but since the fine particles are produced in the fine pulverization step (S38), the pulverization step is sufficient to allow the acid to penetrate the inside of the plant, and the particles should be small enough not to slip through the mesh of the dehydration vessel 15 during dehydration and drying. The size of the pulverized particles is preferably about 5 to 10 mm. Examples of the pulverization method include a mill, mixer, grinder, etc.

[0068] Next, the crushed plant-based raw material 9 (S31) is immersed in an acid solution (S32). Examples of the acid solution include sulfuric acid, hydrochloric acid, citric acid, oxalic acid, malic acid, and formic acid. For example, the citric acid solution is a solution in which citric acid is dissolved in pure water at 1% to 10% by weight. After immersion for about a day, a cleaning process is performed to wash away the organic acid and eluted impurities with pure water or the like. The temperature of the aqueous organic acid solution, including citric acid, is preferably 20°C to 80°C.

[0069] Next, the plant-derived raw material 9 soaked in acid is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S33). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0070] Dehydration allows impurities to be discharged along with the water. In particular, when citric acid is used, the citric acid sequester metal ions, which are discharged to the outside together with the citric acid solution as metal chelate compounds (metal complexes). Therefore, dehydration improves the purity of the silica itself after firing. Next, drying can be done using a dryer, drying in the sun, or natural drying.

[0071] Next, in the firing step (S34), as shown in FIG. 6, the plant-based raw material 9 is placed in a furnace, the pressure inside the furnace is brought to atmospheric pressure so that oxygen can be supplied, the temperature inside the furnace is raised to 300°C, and the temperature (a) is maintained at 300°C for a certain period of time, about 1 to 3 hours.

[0072] Thereafter, the furnace is made ready for oxygen supply, the temperature inside the furnace is raised to 500°C, and the temperature (b) is maintained at 500°C for a fixed period of time of about 1 to 3 hours.

[0073] After that, oxygen is supplied, the temperature inside the furnace is raised to 700°C, and the temperature is maintained at 700°C for a certain period of time (c), about 1 to 3 hours. After the period of maintaining (c), the rice husks are naturally burned, and the total burning time is set to one day. The best burning time for (c) is 10 to 13 hours.

[0074] After that, the fire naturally goes out, and the fired silica 10 is taken out of the furnace. After the retention time of (c), the rice husks are fired by self-sintering, so there is no need to use energy after the retention time of (c), which reduces costs. By maintaining the temperatures of 300°C and 500°C, which require the most energy when firing rice husks, for a certain period of time, the rice husks can be completely fired, improving their purity.

[0075] Next, the fired silica 10 is immersed in an alkaline solution of pH 8 to 11 (S35). The alkaline solution is a solution of sodium bicarbonate, sodium percarbonate, sodium carbonate, or the like dissolved in pure water to a concentration of 1% to 5%, and the liquid temperature is preferably 20° C. to 80° C., and the silica 10 is immersed in the solution for about 2 hours (S35).

[0076] Next, the fired silica 10 is immersed in an acid solution to neutralize it (S36). Examples of the acid solution include sulfuric acid, hydrochloric acid, citric acid, oxalic acid, malic acid, and formic acid. For example, the citric acid solution is a solution in which citric acid is dissolved in pure water at 1% to 10% by weight. After immersion for about a day, a cleaning process is performed to wash away the organic acid and eluted impurities with pure water or the like. The temperature of the aqueous organic acid solution, including citric acid, is preferably 20°C to 80°C.

[0077] Next, the plant-derived raw material 9 soaked in acid is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S37). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0078] Dehydration allows impurities to be discharged along with the water. In particular, when citric acid is used, the citric acid sequester metal ions, which are discharged to the outside together with the citric acid solution as metal chelate compounds (metal complexes). Therefore, dehydration improves the purity of the silica itself after firing. Next, drying can be done using a dryer, drying in the sun, or natural drying.

[0079] Next, the silica 10 is pulverized in the same manner as in S5 described above (S38). The pulverized silica 10 has a particle size distribution ranging from 5 to 20 μm. The pulverization method may be a pulverization method such as a jet mill, a ball mill, or a bead mill.

[0080] Next, melting and spheroidizing is performed in the same manner as in S6 described above (S39). In the thermal spraying method using plasma or gas, crushed silica powder is fed into a high-temperature flame of 2000°C or higher to melt the silica, and the silica melt that has been spheroidized by surface tension is rapidly cooled to obtain spherical silica particles. Because the molten silica is rapidly cooled, the obtained spherical silica particles are amorphous.

[0081] Alternatively, the silica 10 may be spheroidized by a molten flame method, and the temperature of the flame treatment is 1750° C. to 2500° C. As another spheroidization method, spheroidization by spray drying may also be used.

[0082] In addition, in plasma melting, a large volume of thermal plasma is generated and melted at a high temperature exceeding 10,000° C. by a high frequency induction plasma method, making it possible to produce spherical powder of silica 10 with high sphericity. And what is finally produced is amorphous spherical silica particles 11 (S40).

[0083] Example 5 In Example 5, a method for producing silica using rice husks, which are one of the plant raw materials 9 of this embodiment, will be described with reference to FIG.

[0084] The vegetable raw material 9 is pulverized (S41), but since the fine particle size is achieved in the fine pulverization step (S45), it is sufficient to pulverize the plant raw material 9 to the extent that water is absorbed into the plant raw material 9, and since the plant raw material 9 undergoes the dehydration step (S43), it is sufficient that the plant raw material 9 is pulverized to a size that does not pass through the mesh of the dehydration container 15. The size of the plant raw material 9 after pulverization is preferably about 5 mm to 10 mm. Examples of the pulverization method include a mill, a mixer, a grinder, and the like.

[0085] Next, the crushed plant-based raw material 9 (S41) is washed with water (S2). For example, the rice husks are soaked in pure water. After soaking the rice husks for about a day, stones, mud, etc. are washed away. The liquid temperature is preferably between room temperature and 80°C. The water washing (S2) may be performed by pouring water and then stirring. Alternatively, washing may be performed by pouring water little by little while stirring.

[0086] Next, the washed vegetable raw material 9 is placed in a dehydration container 15 and dehydrated in a rotary dehydration device such as a washing machine (S43). The rotation speed during dehydration is preferably 300 to 3000 rpm, and most preferably 500 to 1500 rpm.

[0087] By dehydrating, impurities are removed along with the water. It is then possible to move on to the next firing process without going through a drying process. It has been confirmed that the dehydration process by rotation also promotes the decomposition of the rice husk structure, making it possible to move on to the next process without going through a drying process. This has made it possible to shorten the manufacturing time by reducing the number of processes.

[0088] Therefore, in the cases of Examples 1 to 4, if rotary dehydration is performed, it is not necessarily necessary to carry out a drying process, but drying reduces the effects of corrosion and the like on the machinery.

[0089] Next, in the firing step (S44), as shown in FIG. 6, the plant-based raw material 9 is placed in a furnace, the pressure inside the furnace is brought to atmospheric pressure so that oxygen can be supplied, the temperature inside the furnace is raised to 300°C, and the temperature (a) is maintained at 300°C for a certain period of time, about 1 to 3 hours.

[0090] Thereafter, the furnace is made ready for oxygen supply, the temperature inside the furnace is raised to 500°C, and the temperature (b) is maintained at 500°C for a fixed period of time of about 1 to 3 hours.

[0091] After that, oxygen is supplied, the temperature inside the furnace is raised to 700°C, and the temperature is maintained at 700°C for a certain period of time (c), about 1 to 3 hours. After the period of maintaining (c), the rice husks are naturally burned, and the total burning time is set to one day. The best burning time for (c) is 10 to 13 hours.

[0092] After that, the fire naturally goes out, and the fired silica 10 is taken out of the furnace. After the retention time of (c), the rice husks are fired by self-sintering, so there is no need to use energy after the retention time of (c), which reduces costs. By maintaining the temperatures of 300°C and 500°C, which require the most energy when firing rice husks, for a certain period of time, the rice husks can be completely fired, improving their purity.

[0093] The purity of the silica 10 produced by the above-mentioned production method, as determined by ICP emission spectrometry, is 97.7% to 98.8%. Other typical metals contained include Ca, K, Al, Mg, Mn, Na, P, Zn, etc. Ca is contained at 4700ppm to 11000ppm, K is contained at 750ppm to 15000ppm, Mg is contained at 730ppm to 1500ppm, Mn is contained at 450ppm to 640ppm, Mg is contained at 730ppm to 1500ppm, Mn is contained at 450ppm to 640ppm, P is contained at 270ppm to 470ppm, and Zn is contained at 89ppm to 110ppm.

[0094] Next, the silica 10 is pulverized in the same manner as in S5 described above (S45). The pulverized silica 10 has a particle size distribution ranging from 5 to 20 μm. The method for pulverizing the silica includes a jet mill, a ball mill, a bead mill, and the like.

[0095] Next, melting and spheroidizing is performed in the same manner as in S6 described above (S46). In the thermal spraying method using plasma or gas, crushed silica powder is fed into a high-temperature flame of 2000°C or higher to melt the silica, and the molten silica that has been spheroidized by surface tension is rapidly cooled to obtain spherical silica particles. Because the molten silica is rapidly cooled, the obtained spherical silica particles are amorphous.

[0096] Alternatively, the silica 10 may be spheroidized by a molten flame method, and the temperature of the flame treatment is 1750° C. to 2500° C. As another spheroidization method, spheroidization by spray drying may also be used.

[0097] In plasma melting, a large volume of thermal plasma is generated and melted at a high temperature exceeding 10,000° C. by a high frequency induction plasma method, thereby producing spherical powder of silica 10 with high sphericity. Then, in the final stage, amorphous spherical silica particles 11 are produced (S47).

[0098] Also, during the acid immersion (S2), steam decomposition (S22) and water washing (S42), these processes may be carried out at a temperature of around 120°C and with a pressure of 80 kPa to 150 kPa. Applying pressure has the effect of shortening the process time and accelerating the decomposition of the structure since a large amount of acid remains. This makes it possible to shorten the process time and improve the purity and whiteness of the silica.

[0099] Next, a manufacturing device for firing the silica 10 (S4, S12, S23, S34, S44) will be described with reference to FIG. Fig. 16 is a schematic diagram of a mesh-type continuous firing furnace 100. Fig. 16(A) is a schematic diagram showing the internal structure of the mesh-type continuous firing furnace 100 as viewed from the side. In the mesh-type continuous furnace 100, a mesh-type conveyor belt 102 is provided on a roller 107 to which a drive motor 106 and a drive belt are attached. The mesh-type continuous furnace 100 can reach temperatures from room temperature to 1000°C, and it is possible to adjust the temperature gradient, temperature retention time, etc.

[0100] In the mesh-type continuous firing furnace 100, the vegetable raw material 9 is put into a plurality of mesh-type storage containers 110 which are transported from an entrance 101 to an exit 109. A mesh-type transport belt 102 transports the plurality of mesh-type storage containers 110 from the entrance 101 to the exit 109.

[0101] Since the vegetable raw material 9 generates gas when burned, the mesh-type continuous firing furnace 100 is provided with a waste inlet 105 and an exhaust outlet 104 for external waste in consideration of the exhaust of the gas. This allows combustible gas to be discharged to the outside, reducing the amount of tar remaining in the furnace.

[0102] 16(B) is a plan view of the mesh-type conveyor belt 102. The mesh-type conveyor belt has a mesh-like belt that sends air into the plant-based material 9, making it easier to burn the plant-based material 9.

[0103] 16(C) is a schematic diagram of mesh-type storage container 110. Mesh-type storage container 110 is provided with a mesh (116) made of metal such as stainless steel on the bottom surface of housing 114, which has a certain height, to facilitate the transfer of heat from heater 103 from both the top and bottom and to facilitate the intake of air. Mesh-type storage container 110 also has a handle 112 on the side of housing 114 to make it easy to hold.

[0104] (cosmetics) Next, a cosmetic product 20 using the silica 10 or the amorphous spherical silica particles 11 produced by the production method of Examples 1 to 6 will be described with reference to Table 5 and Figs. 7 to 15.

[0105] Fig. 7 is a micrograph of silica 10 or amorphous spherical silica particles 11 produced by the production methods of Examples 1 to 5. Fig. 7(A), (B), and (C) show amorphous spherical silica particles 11 (indicated by the symbol LU-A10 below) having a particle size of 5 to 10 µm.

[0106] 7(A) is a general photograph of a particle group of amorphous spherical silica particles 11. FIG. 7(B) is a general photograph of a single amorphous spherical silica particle 11. Fig. 7(C) is an enlarged photograph of a single particle of amorphous spherical silica particle 11. As can be seen in Fig. 7(C), the surface has a crater-like shape, and irregularities of various sizes ranging from 0.05 to 0.5 µm are formed all over the surface.

[0107] 7(D), (E), and (F) show silica 10 produced by the production method of Examples 1 to 5, which has only undergone the fine pulverization process (S5, S15, S26, S38, S45, S66) prior to melt spheroidization (S6), etc. Silica 10 with a particle size of 5 to 10 μm (LU-C10, as shown below).

[0108] Fig. 7(D) is an overall photograph of a particle group of silica 10. Fig. 7(E) is an overall photograph of a single particle of silica 10. Fig. 7(F) is an enlarged photograph of a single particle of amorphous spherical silica particle 11. As can be seen in Fig. 7(D), the shapes and sizes are various. Also, as can be seen in Fig. 7(E), the surface is shaped like a crater, and irregular irregularities of 0.05 to 0.5 μm in size are formed as shown in Fig. 7(F).

[0109] Figures 7(G), (H), and (I) show amorphous spherical silica particles 11 (represented by the symbol LU-C5 below) having a particle diameter of 5 μm or less. Figure 7(G) is an overall photograph of a group of amorphous spherical silica particles 11. Figure 7(H) is an overall photograph of a single particle of amorphous spherical silica particle 11. Figure 7(H) is an enlarged photograph of a single particle of amorphous spherical silica particle 11. As can be seen in Figure 7(I), the surface has a crater-like shape, and irregular irregularities of various sizes ranging from 0.01 to 0.1 μm are formed all over the particle.

[0110] [Table 4] Table 4 shows a table of comparative materials used when testing each of the prepared cosmetics 20. LU-A10 is amorphous spherical silica particles 11 having a particle size of 5 to 10 μm produced by the production methods of Examples 1 to 5. LU-C10 is silica 10 having a particle size of 5 to 10 μm produced by the production methods of Examples 1 to 5. LU-C5 is amorphous spherical silica particles 11 having a particle size of 5 μm or less produced by the production methods of Examples 1 to 5.

[0111] SiO-15 is a comparative sample of 15μm porous spherical mineral silica. SiO-16 is a comparative sample of 16μm porous spherical mineral silica. KMP5 is a comparative sample of 5μm dense spherical polymethylsilsesquioxane crosslinked polymer. KSP5 is a comparative sample of 5μm dense spherical vinyl dimethicone / methicone silsesquioxane crosslinked polymer. KSP12 is a comparative sample of 12μm dense spherical vinyl dimethicone / methicone silsesquioxane crosslinked polymer.

[0112] Ny5 is a comparative sample of dense 5 μm particle diameter made of polyamide in a spherical shape. Ny10 is a comparative sample of dense 10 μm particle diameter made of polyamide in a spherical shape. Acl15 is a comparative sample of dense 15 μm particle diameter made of cross-linked polymer of polyacrylic acid ester in a spherical shape. Acl30 is a comparative sample of dense 30 μm particle diameter made of cross-linked polymer of acrylic in a spherical shape. PMM8 is a comparative sample of porous 8 μm particle diameter made of spherical polymethyl methacrylate.

[0113] TA-25 is a comparative sample of porous cellulose acetate in a spherical shape with a particle size of 8-10 μm. C-25 is a comparative sample of porous cellulose in a spherical shape with a particle size of 8-10 μm. C-25N is a comparative sample of dense cellulose in a spherical shape with a particle size of 8-10 μm. D-5 is a comparative sample of dense cellulose in a spherical shape with a particle size of 5 μm. D-10 is a comparative sample of dense cellulose in a spherical shape with a particle size of 10 μm. D-30 is a comparative sample of dense cellulose in a spherical shape with a particle size of 30 μm. TalcEX-10 is a comparative sample of talc in a flaky plate shape with a particle size of 15 μm. MicaY-1800 is a comparative sample of mica in a flaky plate shape with a particle size of 10 μm. PDM-5L is a comparative sample of synthetic mica in a flaky plate shape with a particle size of 6 μm.

[0114] Here, we will explain how to prepare test samples using the above sample. The above sample was mixed with a commercially available foundation in a ratio of 2:18 to prepare a dry sample. In addition, the above sample was mixed with olive oil in a ratio of 2:18 to prepare an oil-added sample. The oil to be added is not limited to olive oil, but can also be jojoba oil, argan oil, rosehip oil, horse oil, sesame oil, macadamia nut oil, avocado oil, coconut oil, marula oil, etc.

[0115] Figure 8A shows the whiteness. The white bars in the graph show the L* values ​​of the color difference meter when the above-mentioned dry sample was applied to the artificial leather surface. The filled bars show the L* values ​​of the color difference meter when the above-mentioned oil-added sample was applied to the artificial leather surface. The L* value is scaled from 0 for black to 100 for white, with the higher the value indicating the whiteness. The higher the value, the greater the hiding power, and the lower the value, the greater the transparency.

number

[0116] FIG. 8B shows chroma. C* shows the numerical value calculated by the formula shown in Equation 1. a* shows the change in color from red to green, and b* shows the change in color from blue to yellow. These numerical values ​​are measured by a color difference meter.

[0117] The white bars in the graph show the C* values ​​when the above-mentioned dry sample was applied to the artificial leather surface. The solid bars show the C* values ​​when the above-mentioned oil-added sample was applied to the artificial leather surface. The higher the C* value, the higher the hiding power, and the lower the value, the higher the transparency.

[0118] Figure 9 shows the L* and C* values ​​shown in Figure 8, obtained by dividing the oiled sample by the dry sample. The white bars in the graph show the L* values. The solid bars show the C* values. The closer the value is to 1, the greater the effect of preventing the effects of wetting with sebum. LU-C10 is close to 1.0, so it is highly effective at preventing the effects of wetting with sebum. From the above results, LU-C10 is evaluated as having high covering power and high resistance to wetting by sebum.

[0119] Figure 10 shows how the foundation created using the above method was applied to a sponge, then applied to an artificial leather sheet to evaluate the variation in color and evaluate uniformity of dispersion. The smaller the standard deviation α, the more uniform the color. The white bars in the graph show the L* values. The solid bars show the C* values. From these results, it was confirmed that LU-C10 and LU-C5 have small variation.

[0120] FIG. 11A shows the degree of lightness measured for each bulk density. The open bars in the graph show the powder values ​​of the dry samples. The filled bars show the powder values ​​of the oil-added samples. LU-C10 was confirmed to have a small bulk density and be light.

[0121] In Figure 11B, the coefficient of kinetic friction (MIU) was measured by performing a reciprocating motion on the surface of the foundation created using the above-mentioned method with a sponge. The white bars in the graph show the numerical values ​​for the powder of the above-mentioned dry sample. The solid bars show the numerical values ​​for the powder of the above-mentioned oil-added sample. It was confirmed that LU-C10 has a small coefficient of kinetic friction. The smaller this value, the lighter the product is and the smoother it spreads.

[0122] Figure 12 shows the drying speed test. A certain amount of the above-prepared foundation was applied to the artificial leather-covered mochi substrate, which was made by covering a piece of mochi with oil blotting paper and then fixing artificial leather on top of that with tape, and the drying speed was measured at room temperature. The figures show the values ​​when the above-mentioned dry sample was applied. The solid bars show the values ​​when the above-mentioned oil-added sample was applied. It was confirmed that LU-C10 had a slow drying speed. The smaller this value, the higher the moisturizing effect.

[0123] Next, we will show the test of blending emulsion. 10mL of emulsion was dispensed into a test tube, to which 0.2% of each of the above comparative powder samples was added and stirred to create an emulsion. FIG. 13A shows a drying speed test similar to that described above for a comparative sample containing emulsion. It was confirmed that U-C10 has a slow drying speed. The smaller this value, the higher the moisturizing effect.

[0124] Figure 13B shows a test in which a certain amount of a comparative sample containing emulsion was added to an artificial leather-coated mochi substrate and the contact angle was measured using a digital microscope. LU-C5 was confirmed to have a low water droplet contact angle. A low contact angle indicates high wettability. The contact angle of LU-C5 is between 30 degrees and 40 degrees. Figure 13C shows the measured dynamic friction coefficient (MIU) of the comparative sample containing the emulsion as described above. It was confirmed that LU-C5 had a large dynamic friction coefficient.

[0125] As described above, when LU-C5 and LU-C10 are added to the emulsion, the drying speed is slowed and the moisturizing effect is enhanced. When a porous powder is added, the moisture evaporation effect is generally enhanced, but the amorphous spherical silica particles 11 of 5μ or less created in this embodiment in particular have a low contact angle, which enhances hydrophilicity and has the effect of retaining moisture. In addition, since the moisture retention is high even after 24 hours, the kinetic friction coefficient (MIU) of the surface is high.

[0126] Next, in the case of tests using a liquid foundation, 0.2% of each of the comparative powder samples was added to 10 mL of liquid foundation dispensed into a test tube, and the mixture was stirred to prepare a liquid foundation.

[0127] Fig. 14A shows the values ​​measured by a color difference meter when the above liquid foundation was applied to the surface of artificial leather. a* shows a solid black bar graph, indicating a change in color from red to green. b* shows a solid light gray bar graph, indicating a change in color from blue to yellow. Small a* and b* values ​​indicate a sense of transparency. LU-C10 shows a relatively small value.

[0128] Figure 14B shows the L* value measured with a color difference meter after applying the above liquid foundation to the surface of artificial leather. A smaller L* value indicates a more transparent finish. LU-C10 shows a relatively small value.

[0129] 15A shows the values ​​measured with a gloss meter when the above liquid foundation was applied to the surface of artificial leather. LU-A10, LU-C10, and LU-C5 have relatively small gloss values ​​and suppress shine. 15B shows the results of applying the above liquid foundation to the surface of artificial leather and measuring the color unevenness with a color difference meter. LU-C10 has a particularly small standard deviation value, indicating high uniformity of dispersion.

[0130] Formulated with LU-C10, it has an extremely slow drying speed, high moisturizing effect, low color unevenness, low MIU, and high contact angle, so it spreads smoothly and forms a uniform oily film, which gives it high moisturizing power, and its low L*, a*, and b* values ​​give it a transparent look. It also has a low gloss, so it gives a natural transparency with less shine and greasiness.

[0131] (Technical features) Below, examples of the technical features of this embodiment are shown in parentheses, but these are not particularly limiting and are merely examples, and the effects that can be expected from these features will also be described.

[0132] The method includes a grinding step (e.g., mainly a grinding step of the plant raw material (S41)) for grinding a plant raw material (e.g., mainly a plant raw material 9 (rice husks, etc.)), a washing step (e.g., mainly a water washing step (S42)) for washing the plant raw material obtained in the grinding step with water, a dehydration step (e.g., mainly a dehydration step (S43)) for storing the plant raw material in a mesh container after the washing step and rotating it with a rotary dehydrator to remove water contained in the plant raw material, a firing step (e.g., mainly a firing step (S44)) for firing the plant raw material, and a fine grinding step (e.g., mainly a grinding step (S45)) for finely grinding the silica obtained in the firing step. If the material is immersed in an acid solution and then dehydrated instead of simply being washed with water, the decomposition will be further accelerated and the drying time will be shortened.

[0133] The above features reduce the time required for drying after immersion in a solution or washing with water, as was previously the case, improving production efficiency, while also accelerating the decomposition of cellulose and other substances and enabling the removal of impurities.

[0134] <Feature 2> The rotation speed of the rotating device is between 300 rpm and 3000 rpm.

[0135] The above features reduce the time required for drying after immersion in a solution or washing with water, as was previously the case, improving production efficiency, while also accelerating the decomposition of cellulose and other substances and enabling the removal of impurities.

[0136] <Feature 3> The calcination process is characterized by including the steps of: making the furnace capable of supplying oxygen; increasing the temperature in the furnace to 300°C; maintaining the temperature at 300°C for a certain period of time; increasing the temperature in the furnace to 500°C; maintaining the temperature at 500°C for a certain period of time; increasing the temperature in the furnace to 700°C; maintaining the temperature at 700°C for a certain period of time; and then calcining the plant-based raw material by natural calcination of the plant-based raw material itself.

[0137] Due to the above characteristics, it is possible to burn cellulose and other materials efficiently by setting a certain time at two temperature ranges where gas is most likely to be produced and calories are consumed. Also, after maintaining a certain time at two stages, it is possible to burn the material without consuming energy by burning it through natural combustion of plant-based materials.

[0138] <Feature 4> The method is characterized by including a steam decomposition step (for example, mainly the steam decomposition step (S22)) in which decomposition of the plant-based raw material is promoted by steam before the burning step.

[0139] The above features facilitate the decomposition of cellulose and other materials, making it possible to burn them efficiently.

[0140] <Feature 5> The silica is crushed to a size of 5 to 10 mm in the fine crushing step of the silica manufacturing method, and then spheroidized to form amorphous spherical silica particles. The silica has a particle size of 5 μm or less, an irregular block shape, and has irregular irregularities of 0.01 to 0.1 μm on the surface.

[0141] Due to the above characteristics, it is possible to provide a cosmetic product that has a relatively small gloss value and is capable of suppressing shine.

[0142] <Feature 6> The silica is characterized in that it is a group of silica particles having a particle size of 5 to 10 μm and an irregular block shape, which is produced by the fine pulverization process of the silica production method, and in which irregular irregularities are formed on the surface of the silica.

[0143] The above features make it possible to provide cosmetics that have an extremely slow drying speed, high moisturizing effect, low color unevenness, and a high contact angle, which allows the product to spread smoothly and form a uniform oily film, resulting in high moisturizing power, and low L*, a*, and b* values ​​for transparency. The product also has a low gloss, making it possible to provide cosmetics that have a natural transparency with reduced shine and greasiness.

[0144] <Feature 7> It is characterized by the addition of silica that creates irregular bumps and recesses of 0.05 μm to 0.5 μm on the crater-like surface.

[0145] Due to the above characteristics, it is possible to provide cosmetics that have an extremely slow drying speed, high moisturizing effect, low color unevenness, and a high contact angle, which allows it to spread smoothly and form a uniform oily film, resulting in high moisturizing power and transparency. It also has a low gloss, so it is possible to provide cosmetics that have a natural transparency with reduced shine and greasiness.

[0146] <Feature 8> A plurality of storage containers (e.g., mainly mesh-type storage containers 110) having a metal mesh-shaped bottom on which the plant-based raw materials are placed; A continuous furnace (e.g., mesh-type continuous firing furnace 100) equipped with a metal mesh-like conveyor belt (e.g., mainly a mesh-type conveyor belt 102) for conveying the container; heater units (e.g., heater 103) for burning the plant-based raw material are provided above and below the conveyor belt; The continuous furnace is characterized by being provided with an exhaust port (for example, mainly the exhaust port 104) for discharging gas generated during combustion in the continuous furnace from inside the furnace to the outside.

[0147] The above features make it possible to provide a silica production bed that can continuously burn a large amount of plant-based raw materials and has a long burning time. In addition, by making the conveyor belt and storage container into a mesh shape, air is sent to the plant-based raw materials, making them easier to burn. [Explanation of symbols]

[0148] 9 Plant-based raw materials 10. Silica 11 Amorphous spherical silica particles 100 mesh type continuous firing furnace 102 Mesh conveyor belt 103 Heater 104 Exhaust port 110 Mesh storage container S41 Crushing process of plant-based raw materials S43 Dehydration process S44 Firing process S45 Grinding process.

Claims

1. a soaking means for soaking the plant raw material in the aqueous solution; a washing means for washing the plant-derived raw material with water; a dehydration device that is housed in a container and dehydrates the water contained in the plant-based raw material by rotation; a baking device that continuously supplies the dehydrated plant-based raw material and bakes it; A silica production system comprising:

2. 2. The silica production system according to claim 1, wherein the washing means washes by stirring while adding water little by little.

3. 2. The silica production system according to claim 1, wherein the washing means washes the silica by stirring after injecting water.

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