Silicate Minerals and Method for Producing the Same

Abstract

To provide a silicate mineral having an average particle diameter larger than 100 nm without containing impurities such as crystalline silica. 【Solution means】The silicate mineral of the present invention has a content of crystalline silica and asbestos of 0.1% by weight or less each. The mineral preferably contains a carbonate and preferably has an average particle diameter of 100 nm or more. Further, the mineral is preferably used in cosmetics, hygiene products, pharmaceuticals, and foods. The silicate mineral of the present invention can be obtained by subjecting a natural silicate mineral to hot water or hydrothermal reaction treatment at pH 9.4 or less.

Description

Technical Field

[0001] The present invention relates to silicate minerals and a method for producing the same.

Background Art

[0002] Silicate compounds are diverse among minerals and are widely used in cosmetics, foods, pharmaceuticals, and industrial products. Deep underground, groundwater is heated by volcanic activity to become high-temperature and high-pressure hot water (subcritical / supercritical water), which dissolves rocks to form a supercritical aqueous solution state. When it is depressurized and cooled near the ground, the solubility decreases and precipitation occurs. This is the principle of the formation of ore veins. As can be seen from the earth and sand components on the ground, silicate compounds are the main constituent components among them. As silicate compounds, in addition to silica SiO 2 not only, but also calcium silicate, magnesium silicate, iron silicate, sodium silicate, etc. containing many metals such as Al, Ca, Fe, K, Na, Mg, etc., or minerals containing multiple metals, and their hydrates are also formed in large numbers.

Table 1

[0003] From its precipitation principle, it is natural that impurities are often contained. Among them, it often contains SiO 2 as an impurity.

[0004] The object of the present invention is to remove these impurities generated in the precipitation process of silicate minerals, and it targets aluminum silicate, calcium silicate, magnesium silicate, iron silicate, etc. and their hydrates. Hereinafter, magnesium silicate hydrate (also referred to as talc, talcum, etc.) will be used as an example to explain this technology, but it is a technology that can be applied to other silicate minerals in principle.

[0005] Magnesium silicate hydrate is widely used in cosmetics, foods, pharmaceuticals, and industrial products. However, since it is a natural mineral, it often contains impurities. When used commercially, toxic substances and heavy metals are separated and removed before use. However, in many cases, these materials, including talc, which is a natural mineral, are likely to contain components that are likely to co-precipitate during mineral formation, such as SiO 2 , and these components that are likely to co-precipitate often contaminate the products. For example, tremolite and chrysotile, which are caused by asbestos, are often contained in small amounts. The inclusion of asbestos is not permitted not only in cosmetics, foods, pharmaceuticals, etc., but also in industrial products. In addition, the inclusion of other crystalline SiO 2 (also referred to as crystalline silica, quartz, etc.) has recently become a problem.

[0006] However, the formation of minerals underground is precipitation due to temperature and pressure, and the composition of the precipitate varies depending on the location where the minerals are mined. Scrutinizing and selecting parts that contain almost no impurities as described above and using them has been considered the only solution, but even then, impurities are often contained in trace amounts, especially in the application fields such as medical, food, and cosmetics, which has become a major problem.

[0007] In addition, focusing on crystalline SiO 2 , since the physical properties required for existing component separation, such as the specific gravity of magnesium silicate hydrate and SiO 2 , are almost the same, separation by centrifugation, sedimentation separation, specific gravity separation, and adsorption operations such as chromatography has been considered impossible.

[0008] Here, it has been proposed to artificially synthesize talc in the form of fine particles using hydrothermal synthesis including a supercritical field (see Patent Document 1).

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] However, the synthetic talc obtained by the method described in Patent Document 1 has a small particle size of 20 nm to 100 nm. In the application fields where hydrous silicate compounds such as talc are actually used, natural minerals are sieved by grinding and used, so the particle size is several tens of μm or more, and even in the smallest case, it is sub-μm or more. From the perspective of user safety (nano risk), it is desirable to provide talc with a larger particle size. In principle, it is possible to grow the particle size by a hydrothermal method or the like, but for artificial synthesis, there are problems in terms of manufacturing cost, productivity, and optimization of properties. Actually, it is not a method for industrially producing particles of several hundreds of nm or more.

[0011] Therefore, even when trying to remove impurities from natural minerals, regarding crystalline silica, in the mixed system of magnesium hydrous silicate and impurity SiO 2 it is possible to dissolve the impurities by making the conditions alkaline in the sense of dissolving and removing the SiO 2 impurities, but at the same time, magnesium hydrous silicate also dissolves. Therefore, there has been no study on separation and removal to leave magnesium hydrous silicate while dissolving and removing the SiO 2 impurities. In principle, as an industrial method, conditions are required to dissolve only SiO 2 without dissolving magnesium hydrous silicate. However, considering that minerals are formed simultaneously in nature in the first place, it is precisely because their solubilities are almost the same that they are mixed, and the search for such conditions is extremely difficult.

[0012] Regarding asbestos, asbestos is serpentine and amphibole. Generally, it has heat resistance and is stable in both acids and alkalis. That is, under the conditions where it can be dissolved and removed, other components, such as magnesium hydrous silicate itself, will be dissolved, which is generally very difficult.

[0013] The present invention has been made in view of such problems, and it is to be able to provide a silicate mineral having an average particle diameter larger than several hundred nanometers without containing impurities such as crystalline silica.

Means for Solving the Problems

[0014] As a result of intensive research, the present inventors have found that by subjecting a silicate mineral derived from a natural mineral to hot water treatment or hydrothermal reaction treatment at pH 9.4 or lower, toxic impurities such as crystalline silica and asbestos can be dissolved in water or removed by reaction modification, and thus the present invention has been completed. Specifically, the present invention provides the following.

[0015] The present invention is a method for producing a silicate mineral powder, which includes a step of subjecting a silicate mineral derived from a natural mineral to hot water treatment or hydrothermal reaction treatment at pH 9.4 or lower. Further, carbonic acid or the like can coexist in the reaction field, thereby controlling the pH to be low and enabling reaction modification and removal of impurities.

[0016] Hydrothermal reaction is widely used as a single crystal growth method for metal oxide crystals, including quartz. Under hydrothermal conditions, metal oxides repeatedly dissolve and precipitate, and crystal growth occurs. This crystal growth is called Ostwald ripening. Unstable fine particles and sharp ends with high surface energy are more likely to dissolve, and single crystal growth proceeds so that more stable faces are exposed. In practice, it is industrially used as a method for promoting faster crystal growth and producing large single crystals by utilizing the mechanism and principle of this Ostwald ripening.

[0017] Since the solubility of metal oxides varies with temperature, generally, in order to promote this single crystal growth, a temperature distribution is created within the crystal growth apparatus to perform crystal growth at a higher speed. Under subcritical hydrothermal conditions or high-pressure supercritical conditions (high water density), a method is adopted in which the raw material is dissolved in a high-temperature field and the seed crystal is grown in a low-temperature field. When utilizing a relatively low-pressure, low-density supercritical water state, conversely, precipitation occurs in a high-temperature (low water density) field, and natural stagnation that easily occurs is actively utilized. Usually, it takes at least several hours, generally several days to several weeks.

[0018] Considering the principle of this Ostwald ripening, if magnesium silicate hydrates such as talc with different particle sizes and shapes are hydrothermally aged, dissolution occurs in both components from fine particles and acicular particles. Different from crystal growth, the present invention is not about the growth of tremolite, chrysotile, or crystalline silica (quartz) that may be contained as impurities, but about the dissolution or reaction modification and removal of impurities. By selectively causing the dissolution or reaction modification of impurities such as crystalline silica while suppressing the dissolution of silicate minerals, the adjustment of the main component silicate minerals free of impurities including crystalline silica is carried out.

[0019] Also, compared with the artificial synthesis of talc using hydrothermal synthesis, in which the adjustment of silicate minerals free of crystalline silica and chrysotile as impurities is also possible in principle, it is excellent in terms of manufacturing cost. Moreover, since the raw material is a pulverized natural mineral, it is possible to recover particles with a particle size of several hundred nanometers or more required in the market.

[0020] Since it is a reaction field where Ostwald ripening occurs, the shape of the recovered silicate mineral particles has fewer fine-grained products and the particle shape is rounder compared to general pulverized natural products. Also, there are more hydroxyl groups on the surface of the product.

[0021] The pH is 9.4 or less. Under high pH conditions, crystalline silica can be dissolved, but at the same time, the dissolution of silicate minerals also occurs. Originally, for the subcritical and supercritical hydrothermal synthesis (artificial synthesis) of silicate minerals, a low pH is desirable. Since silicate minerals precipitate under this condition, it is considered desirable in principle as a condition for dissolving only crystalline silica without dissolving silicate minerals.

[0022] This concept is the same for the removal of impurities in asbestos such as chrysotile. Since asbestos such as chrysotile is a mineral showing basicity, it is possible in principle to set conditions for dissolving these and precipitating silicate minerals by not setting a high pH under hydrothermal conditions.

[0023] These impurities become particularly problematic when the impurity is a needle-like product. However, under hydrothermal conditions, the needle-like substance dissolves from its tip. Considering the dissolution rate and amount of a large amount of silicate minerals, even if the same amount is dissolved, ultimately, it is possible to leave only the silicate minerals present in a large amount.

[0024] An acid can coexist to lower the pH, and carbonic acid can also be used as the acid. In this case, carbonate formation may occur depending on the conditions. The following reaction is known as the talc formation mechanism in the reaction field of mineral formation deep underground.

Number

[0025] This indicates that serpentine (chrysotile) reacts with CO 2 under hydrothermal conditions to form talc. The Mg in chrysotile precipitates as magnesium carbonate. However, since the solubility of magnesium carbonate under hydrothermal conditions is higher than that of other products, it can also be removed by dissolution through a semi-batch extraction operation.

[0026] Also, in recent research, calcium silicate, etc. and CO 2Carbonation by reaction with [substance] has been reported. Not only for the study of mineral formation mechanisms, but also for the hardening of calcium silicate compounds by carbonation (Goto et al., Inorganic Materials, Vol. 5, Jan. 22 - 27 (1998)), CO 2 absorption (CO 2 -SUICOM (registered trademark) process), and the synthesis of artificial marble by the coexistence hydrothermal reaction of calcium silicate by Professor Richard Riman of Rutgers University in the United States, etc. are being put into practical use as research and development, and technological development for problem solving. That is, carbonation proceeds under hydrothermal conditions in the coexistence of CO 2 On the other hand, in the geophysical field, the following are known as another formation mechanism of talc formation underground. 2 This reaction mechanism is a reaction in which talc is formed in the coexistence of silica under hydrothermal conditions. As described above, it is suggested that it is possible to modify it to talc through the reaction between carbonate and silica. 2 That is, tremolite mixed as a trace component is

[0027] Ca

Number

[0028] Ca

[0029] (Mg,Fe) Ca 2 (Mg,Fe) 5 Si 8 O 22 (OH) 2 (where Mg / (Mg + Fe) = 1.0 - 0.9) However, when tremolite is mixed in trace amounts, under hydrothermal conditions, not only dissolution and removal occur, but also in the coexistence of CO 2 In the coexistence, it carbonates, and at the same time, the silica component existing as an impurity also dissolves and reacts, resulting in denaturation to talc.

[0030] In the present invention, the warm water or hot water treatment or the hydrothermal reaction treatment is preferably carried out in the co - existence of Mg ions. When crystalline silica or the like is contained in the mineral, from an equilibrium theory perspective, co - existing Mg may promote the formation of magnesium silicate. Simply put, there is also a reaction in which SiO 2 reacts with Mg to form a composite. In reality, although Mg ions and Si ions co - exist due to the dissolution of silica and magnesium silicate, if magnesium ions are supplied, the dissolution equilibrium of silica and magnesium silicate can be made to predominantly result in the dissolution of silica.

[0031] The silicate mineral derived from natural minerals as raw materials is provided by pulverizing natural minerals. Therefore, it is difficult to make the average particle size less than 200 nm, and for the product after the hydrothermal reaction treatment, the average particle size is 200 nm or more.

[0032] Therefore, according to the present invention, talc having an average particle size larger than 100 nm can be provided without containing impurities such as crystalline silica and asbestos components.

[0033] In the present invention, it is preferable that the temperature in the warm water or hot water treatment or the hydrothermal reaction treatment is 70°C or higher and 370°C or lower, and the pressure is equal to or higher than the saturated vapor pressure of water.

[0034] According to the present invention, since heat at a low temperature of 370°C or lower (preferably 300°C or lower, more preferably 250°C or lower, still more preferably 200°C or lower, particularly preferably 150°C or lower) can be used to dissolve and react to remove impurities such as crystalline silica or asbestos, it is more excellent in terms of manufacturing cost. As the low - temperature heat, not only the heat from the heat source device but also the reuse of waste heat in the factory can be considered.

[0035] The present invention can be applied to any of the batch - type device, semi - batch - type device, and flow - through device. However, it is preferable to carry out the warm water or hot water treatment or the hydrothermal reaction treatment using a semi - batch - type device or a flow - through device, and it is more preferable to carry out the warm water or hot water treatment or the hydrothermal reaction treatment using a semi - batch - type device.

[0036] The solubility of silica in pure water has been reported. However, in the case of hydrothermal treatment of minerals containing other ions, as in this system, the dissolution of those minerals naturally occurs, and the solubility differs from that of silica in high-temperature, high-pressure water. In general, the solubility of a specific component in the presence of other minerals and the concentration of dissolved chemical species can be solved by simultaneously solving the solubility equilibrium equation of any substance, and further, the dissociation equilibrium of water and the charge balance. The necessary chemical equilibrium can be predicted with good accuracy, including in the supercritical region, using the HKF (Helgeson Kirkham Flouer) model and the improved HKF model by Sue et al. (Sue, K., Hakuta, Y., Smith, RL, Adschiri, T., & Arai, K. (1999). Solubility of lead(II) oxide and copper(II) oxide in subcritical and supercritical water. Journal of Chemical & Engineering Data, 44(6), 1422-1426. https: / / doi.org / 10.1021 / je9901029)

[0037] For example, the addition of alkali or the influence of coexisting ions increases the saturated solubility. It also suggests that in the process of mineral precipitation underground, when minerals precipitate and silica precipitates as an impurity, the solubility of the precipitated mineral is low and the precipitation rate is high. It is inferred that the situation is favorable for silica to dissolve not only in terms of equilibrium theory but also in terms of kinetics. This has been verified experimentally, and it can be fully explained that dissolution is achieved more than 10 times faster not only in terms of equilibrium theory but also in terms of kinetics.

[0038] The optimum amount of water to be passed through when operating a reaction system is determined based on the theory of equilibrium and kinetics.

[0039] By using a semi-batch apparatus, heat recovery and preheating in hot water / hot water treatment or hydrothermal reaction treatment can also be performed, making it even more excellent in terms of manufacturing cost. In addition, since impurities such as crystalline silica and asbestos that have been extracted and removed can be removed outside the system, contamination due to their reprecipitation can be prevented.

[0040] When the reaction apparatus is a semi-batch apparatus, the amount of the aqueous solvent supplied to the semi-batch apparatus is preferably 0.1 times or more of the theoretical amount that saturates and dissolves the crystalline silica contained in the silicate mineral as a raw material in the reaction solution containing coexisting ions in the reaction field. Alternatively, the amount of crystalline silica contained in the silicate mineral as a raw material charged into the semi-batch apparatus is preferably 10 times or less of the theoretical amount that saturates and dissolves in the reaction solution containing coexisting ions in the reaction field.

[0041] When using a flow-through apparatus, the silicate mineral is supplied in a suspended state in water, and hot water / hot water treatment or hydrothermal reaction treatment is performed. Heat recovery at the outlet and further utilization as preheating of the raw material can be carried out. Unlike the semi-batch apparatus, there is no heat loss during the temperature rise and cooling of the extraction tank, so the heat recovery rate is improved. At this time, there is a possibility that silica dissolved in the cooling section may reprecipitate in the subsequent cooling section. To avoid this, it is necessary to suppress the Ostwald ripening and recrystallization growth of the residual silica by sufficient dissolution of crystalline silica and rapid cooling. The condition study can be carried out by a small-scale batch test.

[0042] In addition, the concentration of the silicate mineral water slurry supplied to the flow-through apparatus is preferably 0.1 times or more of the theoretical amount that saturates and dissolves the crystalline silica contained in the silicate mineral as a raw material in the reaction solution containing coexisting ions in the reaction field.

Advantages of the Invention

[0043] According to the present invention, a silicate mineral having an average particle diameter larger than several hundred nanometers can be provided without containing impurities such as crystalline silica.

Brief Description of the Drawings

[0044]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0045] Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention.

[0046] <Manufacturing Apparatus for Magnesium Silicate Hydrate Powder> Figure 1 is a schematic diagram of the manufacturing apparatus 1 for magnesium silicate hydrate powder.

[0047] The manufacturing apparatus 1 includes an extraction means 10 and, if necessary, a cooling means 20.

[0048] 〔Extraction Means 10〕 The extraction means 10 is a device that brings a raw material liquid into contact with an aqueous material and subjects the raw material to hot water or hot water treatment or hydrothermal reaction treatment. The form of the extraction means 10 may be any of a batch device, a semi-batch device, and a continuous device. However, since the temperature in hydrothermal reaction treatment or the like can be made lower, and not only the heat from the heat source device but also the waste heat in the factory can be utilized, which is excellent in terms of manufacturing cost, the extraction means 10 is preferably a batch device or a semi-batch device, and it is more preferable to perform hot water or hot water treatment or hydrothermal reaction treatment using a semi-batch device.

[0049] By using a semi-batch device, heat recovery and preheating in hot water / thermal water treatment or hydrothermal reaction treatment can also be performed, making it even more excellent in terms of manufacturing cost. In addition, since impurities such as crystalline silica and asbestos that have been extracted and removed can be removed outside the system, contamination due to their reprecipitation can be prevented.

[0050] Also, the form of the extraction means 10 may be a continuous device (flow-through device). When using a flow-through device, the silicate mineral is supplied in a suspended state in water, and hot water or thermal water treatment or hydrothermal reaction treatment is performed. Heat recovery at the outlet and further utilization as preheating of the raw material can be carried out. Unlike the semi-batch device, there is no heat loss during the temperature rise and cooling of the extraction tank, so the heat recovery rate is improved. At this time, there is a possibility that silica or the like dissolved in the cooling section may reprecipitate in the subsequent cooling section. To avoid this, sufficient dissolution of crystalline silica and rapid cooling are required to suppress the Ostwald ripening and recrystallization growth of the residual silica. The condition study can be carried out by a small-scale batch test.

[0051] Hereinafter, unless otherwise specified, the extraction means 10 will be described as a semi-batch device, but it is not limited to this.

[0052] [Raw material] The raw material charged into the extraction means 10 is a silicate mineral, which may be derived from a natural mineral or a synthetic mineral, but preferably a silicate mineral derived from a natural mineral.

[0053] The type of metal constituting the silicate mineral is not particularly limited, and in addition to alkali metals and alkaline earth metals, aluminum, iron, etc. can be mentioned. Specific examples of silicate minerals include aluminum silicate, magnesium silicate, calcium silicate, iron silicate, or silicate minerals containing multiple kinds of these metals. Also, the silicate mineral may be a hydrated silicate mineral as its hydrate.

[0054] For example, when the silicate mineral is a natural mineral such as talc (magnesium hydrosilicate), according to the Enforcement Regulations of the Industrial Safety and Health Act (Cabinet Order No. 318 of 1972) and the Asbestos Hazard Prevention Regulations (Ministry of Health, Labour and Welfare Ordinance No. 21 of 2005), the content rate of asbestos (tremolite, chrysotile, etc.) contained in the natural mineral is set at 0.1% or less. Therefore, it is preferable to use a silicate mineral with a content rate of 0.1% or less as a raw material.

[0055] By the way, as a method for determining the content rate of asbestos in talc using the X-ray diffraction method, "Analysis Method for Asbestos Content Rate in Natural Minerals", which is an annex to Kikan Hokabu No. 0828001, is adopted. In this method, it is assumed that a general-purpose X-ray diffractometer (XRD device) is used, and the measurement conditions are as follows ("Analysis Method for Asbestos Content Rate in Talc", Asbestos Analysis Manual for Preliminary Investigation Based on the Asbestos Regulations, March 2018, Ministry of Health, Labour and Welfare). Tube voltage: 40 kV or more Tube current: 30 mA or more Anticathode: Cu Monochromatization: Graphite monochromator or Ni filter Detector: Scintillation counter, proportional counter, Geiger counter, semiconductor detector, etc. Slit system: Receiving slit 0.3 mm or 0.2 mm Divergence slit: 1° Scattering slit: 1° Goniometer scanning speed: 1 / 8° per minute or less Time constant: Use an appropriate time constant. Full scale of chart: For the measurement of the intensity of the diffraction line, obtain the net peak area after subtracting the background. Select an appropriate full scale on the recording chart so that the diffraction line can be confirmed as a peak.

[0056] Generally, in the measurement of trace components, the measurement peak may be hidden in the noise of the baseline, and in order to increase the signal / noise ratio, it is necessary to set the integration time to a long time. As a result, it is possible in principle to detect trace amounts without using a strong radiation source.

[0057] However, if evaluated within the measurement time used for general crystal structure analysis, the integration time may be insufficient to fully detect the peaks, and the asbestos content may be determined to be 0.1% by weight or less, which is the safety standard.

[0058] In the invention described in this embodiment, long-time measurement is carried out with full consideration of that point, and analysis is performed based on the result of creating a calibration curve based on precise baseline evaluation. The asbestos is removed by reaction modification to make the asbestos content truly 0.1% by weight or less, that is, while depending on the determination result by a general-purpose X-ray diffractometer as stipulated in the attached table of Kikanhoka No. 0828001, by making full use of precise analysis methods, it is confirmed with sufficient accuracy that the safety standard in the attached table is achieved.

[0059] [Dispersion medium] Moreover, the dispersion medium for dispersing the raw materials is an aqueous material. The aqueous material refers to water, a polar organic solvent, or a mixed solvent of water and a polar organic solvent. Examples of the aqueous material include water, alcohols, carboxylic acids, ketones, ethers, esters, amides, amines, sulfur compounds, etc. and mixtures thereof.

[0060] Examples of the alcohols include methanol, ethanol, isopropyl alcohol, t-butyl alcohol, propylene glycol, and phenol.

[0061] Examples of the carboxylic acids include lower carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, and caproic acid.

[0062] Examples of the ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0063] Examples of the ethers include ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, tetrahydrofuran, dioxane, and methyl cellosolve.

[0064] Examples of esters include ethyl acetate and butyl acetate.

[0065] Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide, nitromethane, and acetonitrile.

[0066] Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, and hexamethylenediamine.

[0067] Examples of sulfur compounds include dimethyl sulfoxide.

[0068] Among them, since it is easy to handle, the aqueous material preferably contains one or more selected from water, alcohols, and carboxylic acids, and more preferably water.

[0069] Also, for controlling the reaction field, a pH adjuster, an oxidizing agent, or a reducing agent can be added to the aqueous material.

[0070] Examples of the pH adjuster include hydrochloric acid, nitric acid, acetic acid, sulfuric acid, carbonic acid, or their ammonium salts as acids, and potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, or ammonia as alkalis.

[0071] Examples of the oxidizing agent / reducing agent include hydrogen peroxide, oxygen, nitric acid, formic acid, hydrazine, hydrogen, ammonia, ethanol, and formaldehyde.

[0072] These substances not only simply relate to the solubility of the target impurities but also function as reactive substances.

[0073] For example, carbonic acid or CO in the aqueous material 2Coexistence can result in carbonate formation, and further, through reaction with silica, transformation from toxic impurity minerals to non-toxic carbonate minerals or talc may occur.

[0074] Also, it is preferable that Mg ions are added to the aqueous material. As a result, the subsequent warm water or hot water treatment or hydrothermal reaction treatment will be carried out in the presence of Mg ions.

[0075] When crystalline silica or the like is contained in the mineral, from an equilibrium perspective, coexistence of Mg may promote the formation of magnesium silicate. Simply put, there is also a reaction in which SiO 2 combines with Mg. However, in reality, although Mg ions and Si ions will coexist due to the dissolution of silica and magnesium silicate, if magnesium ions are supplied, the dissolution equilibrium of the silica and magnesium silicate can be made to predominantly result in the dissolution of silica. Therefore, it is preferable that Mg ions are added to the aqueous material.

[0076] [Raw material liquid] In this embodiment, a raw material liquid in which the raw materials are dispersed using a dispersion medium is charged into the extraction means 10. The form of the raw material liquid can be charged as a powder or as a fluid with fluidity. If it has fluidity, it is not particularly limited, and examples include an aqueous solution, slurry, paste, or suspension containing the raw material components.

[0077] In addition, when it is difficult to prepare a water slurry, the raw materials may be dispersed in an aqueous material such as ethanol to form a slurry.

[0078] When the reaction apparatus is a semi-batch apparatus, the amount of the aqueous solvent supplied to the semi-batch apparatus is preferably 0.1 times or more, more preferably 0.3 times or more, still more preferably 0.5 times or more, and even more preferably 0.8 times or more of the theoretical amount for saturatingly dissolving the crystalline silica contained in the silicate mineral as a raw material in the reaction solution containing coexisting ions in the reaction field. Alternatively, the amount of the crystalline silica contained in the silicate mineral as a raw material charged into the semi-batch apparatus is preferably 10 times or less, more preferably 3.5 times or less, still more preferably 2 times or less, and even more preferably 1.3 times or less of the theoretical amount for saturatingly dissolving it in the reaction solution containing coexisting ions in the reaction field.

[0079] In this specification, it is stated that the amount of the crystalline silica is preferably 0.1 times or more of the theoretical amount for saturatingly dissolving it in the reaction solution containing coexisting ions in the reaction field. Stated simply in terms of chemical equilibrium theory, the suitable amount of the crystalline silica would be equal to or more than the theoretical amount of water for saturating dissolution, and the degree of freedom is narrow. However, in the present invention, the reaction rate theory rather than the chemical equilibrium theory is dominant, and the property that silica is more soluble than talc is utilized. For example, when an alkali is added or when Mg ions are added, the chemical equilibrium changes. Also, since the dissolution rate of the crystalline silica becomes higher than that of other minerals such as talc at the same time, in the case of semi-batch, continuous flow apparatus treatment, or batch treatment in a short time, it becomes kinetically advantageous, so the amount of the crystalline silica can be much less than the theoretical amount of water for saturating dissolution. Therefore, regarding the amount of the crystalline silica, the degree of freedom is high, and 0.1 times or more of the theoretical amount is sufficient.

[0080] The same applies when the extraction means 10 is a continuous flow apparatus. The concentration of the silicate mineral water slurry supplied to the continuous flow apparatus is preferably 0.1 times or more, more preferably 0.3 times or more, still more preferably 0.5 times or more, and even more preferably 0.8 times or more of the theoretical amount for saturatingly dissolving the crystalline silica contained in the silicate mineral as a raw material in the reaction solution containing coexisting ions in the reaction field.

[0081] In the present invention, the theoretical amount of saturation dissolution with respect to the reaction solution containing coexisting ions in the reaction field can be obtained using the HKF (Helgeson Kirkham Flouer) model. The solubility evaluation method is as described above.

[0082] The pH of the raw material liquid charged into the extraction means is 9.4 or less. If the pH exceeds 9.4, even when hydrothermal reaction treatment or the like is performed using magnesium silicate hydrate derived from natural minerals as a raw material, there is a possibility that the crystalline silica that can be contained in the raw material cannot be sufficiently dissolved, which is not preferable.

[0083] In order to more preferably dissolve impurities in the solvent, the upper limit of the pH is preferably 7 or less. Further, from the viewpoint of causing the modification from impurity minerals to talc formation by coexisting carbonic acid or CO 2 The pH is more preferably 6 or less, and even more preferably 5 or less.

[0084] The lower limit of the pH is not particularly limited, but from the viewpoint of suppressing the corrosion of the apparatus including the extraction means 10, the lower limit of the pH is preferably 1 or more, and more preferably 2 or more. In addition, from the viewpoint of causing the modification from impurity minerals to talc formation by coexisting carbonic acid or CO 2 The pH is more preferably 3 or more, and even more preferably 4 or more.

[0085] The timing of being in the coexistence of an acid or a base is not particularly limited, and it is sufficient if it is in the coexistence of an acid or a base before the raw material liquid and the aqueous material come into contact in the extraction means 10. However, in order to simplify the configuration of the production apparatus 1, it is preferable to supply an acid or a base in the raw material adjustment stage to make the raw material liquid acidic or basic.

[0086] Although not essential, the raw material liquid is preferably degassed. Examples of degassing devices for the raw materials include existing technology degassing devices such as ultrasonic degassing devices, vacuum degassing devices, degassing devices that send rare gases into the raw material liquid, and degassing devices using permeable membranes, as well as degassing devices that combine these existing technology degassing devices. By degassing the raw material liquid, corrosion of the extraction means 10 and the cooling means 20 due to dissolved oxygen can be suppressed.

[0087] [Supply of aqueous material] Next, the aqueous material continuously supplied to the extraction means 10 will be described.

[0088] Examples of the type of aqueous material include the materials described above as the dispersion medium.

[0089] Although not essential, the aqueous material is preferably degassed. Examples of degassing devices for the aqueous material include the devices described above as degassing devices for the raw materials. By degassing the aqueous material, fluctuations in the supply amount of the aqueous material caused by bubbles generated by dissolved gas can be suppressed. In addition, corrosion of the extraction means 10 and the cooling means 20 due to dissolved oxygen can be suppressed. Also, dissolved oxygen affects the redox state of the hydrothermal treatment reaction field, and the presence of gases such as CO 2 which strongly affects the reforming reaction under hydrothermal conditions is also an important factor for controllable treatment.

[0090] The aqueous material is in a pressurized state by a pressure pump or the like. By pressurizing and further heating the aqueous material, the aqueous material can be brought into a subcritical state and continuously supplied to the extraction means 10.

[0091] The pressurized aqueous material is preferably hot water or subcritical aqueous material. When the aqueous material is water, subcritical water has a high solubility in silica. Therefore, it is preferable that after pressurization, the water is in a liquid state (liquid phase) or mainly contains the liquid phase. However, even water in a state called gaseous water or water vapor (or steam) may form a condensed phase between particles due to capillary force and exhibit the same behavior as liquid water, so these states of water are also included. Also, when the aqueous material is in a supercritical state, a high density is required to exhibit a high solubility, and the pressure for this purpose needs to be higher than the critical pressure, which is not desirable for industrial mass production. Moreover, the amount of hydroxy groups generated on the raw material surface is less in the pre-critical state compared to when it is in the pre-critical state, which may affect the dissolution of crystalline silica, asbestos, etc. that may be contained in the raw material.

[0092] The "warm water condition, hot water condition, or hydrothermal condition" according to the present invention is defined as a coexistence condition of liquid water having a reaction temperature of 70°C or higher and 370°C or lower. However, when fine particles are the target, due to the reaction and dissolution action in the condensed state by the capillary force between the fine particles, in such a special case, the supply system may be a condition in which water in a state called gaseous water vapor (or steam) coexists.

[0093] The pressure of the pressurized aqueous material is equal to or higher than the saturated vapor pressure. If it is less than the saturated vapor pressure, even when the raw material liquid is brought into contact with the pressurized aqueous material, there is a possibility that impurities such as crystalline silica and asbestos that may be contained in the raw material cannot be sufficiently dissolved or removed by reaction modification, which is not preferable.

[0094] However, as a special example, even when the particle size is small and the capillary force acts between the particles, that is, even when it is water in a state called water vapor (or steam) with a pressure less than the saturated vapor pressure, the same dissolution effect may be exhibited.

[0095] Since the removal of impurities such as crystalline silica and asbestos that may be contained in the raw material can be more suitably advanced, it is desirable that the pressure of the aqueous material after pressurization be equal to or higher than the saturated vapor pressure at the treatment temperature. For example, when the treatment temperature is 120 °C, it is 0.2 MPa or higher, and when it is 170 °C, it is 0.8 MPa or higher. It is lower at lower temperatures and higher at higher temperatures. At the critical point of 374 °C, it is 22.1 MPa or higher. The pressure of the aqueous material after pressurization is preferably 0.2 MPa or higher, more preferably 0.5 MPa or higher, and even more preferably 1 MPa or higher. Even at a lower temperature, for example, 70 °C, the solubility decreases, so the treatment efficiency and treatment speed decrease, but the same removal effect is expected in principle. In that case, since it is 0.03 MPa and below atmospheric pressure, the operation can be carried out at normal pressure and hot water treatment can be performed.

[0096] Also, the pressure of the aqueous material after pressurization is 40 MPa or lower in the supercritical region, more preferably 20 MPa or lower, and even more preferably 10 MPa or lower. However, basically, if it is equal to or higher than the saturated vapor pressure, a liquid phase is formed, and above that, even if the pressure is increased, the water density hardly changes, so an increase in solubility cannot be expected. Therefore, if it is a few atmospheres higher than the saturated vapor pressure, a sufficient dissolution effect can be expected. Conversely, if the pressure of the aqueous material is too high, the cost for enhancing the pressure resistance of the production apparatus 1 significantly increases, and the extraction means 10 is also likely to deteriorate, which is not preferable.

[0097] The type of heating device for heating the aqueous material is not particularly limited. Examples of the heating device include a heating device that irradiates the aqueous material with microwaves, a heating device that heats the aqueous material by heat conduction from a heating element such as a heater, etc. By heating the pressurized aqueous material, the aqueous material can be brought into a subcritical state.

[0098] There are also cases where high-temperature steam can be utilized. By passing the steam through a heat exchanger or using it in combination with the above heating device, pressurized water can also be produced. When clean heating steam that does not contain impurities at a temperature higher than the treatment temperature is available, it is also possible to directly introduce the steam. By controlling the pressure with a pressure control valve, the steam can be made into a liquid phase and used as heating water for extraction.

[0099] If the temperature is 70°C or higher, extraction of crystalline silica contained in the raw material is possible. The saturated vapor pressure of water at 70°C is approximately 0.03 MPa, at 100°C is approximately 0.1 MPa, at 120°C is approximately 0.2 MPa, and at 170°C is approximately 0.8 MPa.

[0100] The temperature of the aqueous material after heating is 70°C or higher. If it is less than 70°C, even when the raw material liquid is brought into contact with the pressurized aqueous material, there is a possibility that impurities such as crystalline silica and asbestos that may be contained in the raw material cannot be sufficiently dissolved or removed by reaction modification, which is not preferable.

[0101] Since the dissolution or reaction modification and removal of impurities such as crystalline silica and asbestos that may be contained in the raw material can proceed more preferably, the temperature of the aqueous material after heating is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher.

[0102] Also, the temperature of the aqueous material after heating is 370°C or lower, preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. If the temperature of the aqueous material is too high, the amount of hydroxyl groups on the raw material surface will instead decrease, which is not preferable.

[0103] According to the present embodiment, since impurities such as crystalline silica or asbestos can be dissolved and removed by reaction using low-temperature heat of 370 ° C or lower (preferably 300 ° C or lower, more preferably 250 ° C or lower, still more preferably 200 ° C or lower, particularly preferably 150 ° C or lower), it is more excellent in terms of manufacturing cost. As the low-temperature heat, not only the heat from the heat source device but also the reuse of waste heat in the factory can be considered.

[0104] [Contact between the raw material liquid and the aqueous material] The raw material liquid is charged into the extraction means 10, and then the aqueous material is continuously supplied to the extraction means 10, so that the raw material liquid and the aqueous material come into contact. The raw material liquid is instantaneously heated to the subcritical temperature by the amount of heat possessed by the aqueous material, and the reaction between the raw material liquid and the aqueous material is started. By this reaction, an extraction reaction or a modification reaction of crystalline silica, asbestos, etc. that may be contained in the raw material into the aqueous material starts.

[0105] The shape of the extraction means 10 is not particularly limited as long as it maintains the subcritical state, which is the extraction condition of crystalline silica into the aqueous material, for a predetermined time. Examples of the shape of the extraction means 10 include a reactor covered with a constant temperature layer such as a spiral tube wound multiple times inside a heating cylinder, a molten salt bath jacket, and a fluidized sand bath.

[0106] By making the shape of the extraction means 10 a spiral tube wound multiple times inside a heating cylinder or a reactor covered with a constant temperature layer, temperature changes and temperature unevenness of the mixture of the raw material liquid and the aqueous material due to heat conduction through the device wall surface can be prevented, and precise temperature control required for impurity extraction in the subcritical state can be realized.

[0107] From the outlet of the extraction means 10, a high-temperature and high-pressure fluid in which impurities such as crystalline silica and asbestos are dissolved flows out. Since the solubility, that is, the solution concentration is low, and it is relatively low temperature and low pressure, it can be removed as it is. After extraction, a high-temperature and high-pressure fluid containing magnesium hydrosilicate derived from natural minerals from which impurities have been removed is discharged from the extraction means 10.

[0108] From the viewpoint of appropriately removing impurities such as crystalline silica and asbestos, the time of the hydrothermal reaction treatment in the extraction means 10 is preferably 1 minute or more, more preferably 5 minutes or more, and even more preferably 10 minutes or more.

[0109] On the other hand, from the viewpoints of production efficiency and suppressing the deterioration of the extraction means 10, and further reducing the effect of impurity crystal growth due to Ostwald ripening, the time of the hydrothermal reaction treatment is preferably 10 hours or less, more preferably 5 hours or less, and even more preferably 2 hours or less.

[0110] 〔Cooling means 20〕 It is not essential to provide the cooling means 20. The cooling means 20 may be provided as an optional configuration as needed. When the temperature and pressure are relatively high or the elution concentration is high, there is a risk of damaging the pressure control valve due to the re-precipitation of the dissolved impurities by cooling before the pressure control valve. In such a case, by installing the cooling section 20, the load on the subsequent pressure control valve can be reduced by re-precipitating and removing the dissolved impurity components.

[0111] Cooling is performed by mixing the high-temperature and high-pressure fluid supplied from the extraction means 10 with the low-temperature and high-pressure aqueous material pressurized by a pressure pump or the like. By mixing the high-temperature and high-pressure fluid with the low-temperature and high-pressure fluid, the heat quantity associated with the state change of the fluid, that is, the heat quantity corresponding to the latent heat of evaporation, can be quickly removed, and safe and stable operation can be performed. Furthermore, if the high-temperature and high-pressure fluid is cooled to below the critical temperature by this mixing, the high-temperature and high-pressure fluid can be rapidly cooled, and the reaction for generating particles can be stopped almost instantaneously. Therefore, the product particles can be made to have a substantially uniform particle size.

[0112] When operating at a low temperature, such a cooling method may be used. However, when operating at a relatively high temperature, heat recovery may be required from the viewpoint of energy utilization. In that case, a cooling pipe is installed for indirect cooling, that is, heat exchange, and the recovered heat is used for preheating the raw material or the circulating water.

[0113] Regarding the recovery of particles from the extraction tank 10, when the container is charged with powder, the particles are recovered as they are. When recovering with a slurry, the product particle-containing fluid is separated into product particles and fluid through a filter. The type of filter is not particularly limited, and for example, an in-line filter can be mentioned. The filter can collect magnesium hydrosilicate derived from natural minerals from which impurities have been removed.

[0114] In the semi- batch operation, since impurities are dissolved and removed, the cooling operation of the extractor 10 is not important. However, when this system is operated in a batch operation, upon cooling, the dissolved impurities will precipitate onto the silicate mineral which is the product. In that case, if the cooling rate is slow, re-precipitation of the crystalline component may occur, so the cooling operation of the entire apparatus becomes important.

[0115] <Silicate mineral> The average particle diameter of the silicate mineral obtained as a product is preferably 100 nm or more. When the raw material is a natural mineral, the silicate mineral is provided by pulverizing the natural mineral. Therefore, it is difficult to make the average particle diameter less than 100 nm, and for the product after the hydrothermal reaction treatment, the average particle diameter is also 100 nm or more.

[0116] From the perspective of the safety of talc users, the average particle diameter is more preferably 200 nm or more, still more preferably 500 nm or more, even more preferably 1 μm or more, and particularly preferably 5 μm or more.

[0117] Generally, when using natural talc minerals, a pulverization treatment is often performed and it is classified with a sieve. In that case, the particle diameter further becomes as large as several tens of μm or more. For finer particles, a gas phase classification method is used, but in that case too, generally it is about several μm, and as a special example, sub-μm particle recovery is also possible.

[0118] In the present invention, the average particle diameter refers to the median diameter D50 by the centrifugal sedimentation method measured according to JIS R1619.

[0119] Also, from the perspective of industrial manufacturing efficiency, the lower limit of the treatment concentration of the silicate mineral is preferably 1% by weight or more, more preferably 3% by weight or more. The upper limit of the treatment concentration of the silicate mineral is preferably 30% by weight or less, more preferably 20% by weight or less. Among them, even when the concentration of impurities (crystalline silica and asbestos) in the silicate mineral is relatively high, the upper limit of the treatment concentration of the silicate mineral is more preferably 10% by weight or less, and particularly preferably 5% by weight or less, in that impurities can be appropriately treated.

[0120] Also, the content of crystalline silica in the silicate mineral obtained as a product is 0.1% by weight or less, more preferably 0.08% by weight or less, still more preferably 0.05% by weight or less, and even more preferably below the detection limit.

[0121] Also, the content of asbestos in the silicate mineral powder obtained as a product is 0.1% by weight or less, more preferably 0.08% by weight or less, still more preferably 0.05% by weight or less, and even more preferably below the detection limit.

[0122] In this embodiment, the contents of crystalline silica and asbestos shall be determined using an X-ray diffractometer. In that case, the conditions of the X-ray diffractometer shall be as follows. Tube voltage: 45 kV Tube current: 200 mA Anticathode: Cu Monochromatization: graphite monochromator Detector: scintillation counter SC-70S Slit system: light-receiving slit box 1 1.000 mm Light-receiving slit box 2 1.125 mm Incident slit box 1.000 mm Longitudinal limiting slit 15 mm Goniometer scanning speed: 0.10° per minute Full scale of the chart: For the intensity measurement of the diffraction line, the net peak area obtained by subtracting the background is determined. Select an appropriate full scale on the recording chart such that the diffraction line can be confirmed as a peak.

[0123] The X-ray diffractometer can be set to this condition if it is, for example, SmartLab 9MTP (manufactured by Rigaku Corporation).

[0124] Among crystalline silica, the content of quartz shall be determined from the peak intensity at a diffraction angle (2θ) of 26.6° using a calibration curve obtained using a standard quartz sample in powder X-ray diffraction. Also, the content of cristobalite shall be determined from the peak intensity at a diffraction angle (2θ) of 22.0° using a calibration curve obtained using a standard cristobalite sample in powder X-ray diffraction. Further, the content of tridymite shall be determined from the peak intensities at diffraction angles (2θ) of 20.5° and 21.6° using a calibration curve obtained using a standard tridymite sample in powder X-ray diffraction.

[0125] Among asbestos, the content of tremolite shall be determined from the peak intensity at a diffraction angle (2θ) of 10.4° using a calibration curve obtained using a standard tremolite sample in powder X-ray diffraction. Also, the content of chrysotile shall be determined from the peak intensities at diffraction angles (2θ) of 12.1° and 24.3° using a calibration curve obtained using a standard chrysotile sample in powder X-ray diffraction.

[0126] For the rest, it shall comply with the Asbestos Analysis Manual [Version 1.20] of the preliminary investigation based on the Asbestos Act, March 2018, Ministry of Health, Labour and Welfare, "8.4.3.1. Method for Analyzing the Asbestos Content in Talc".

[0127] Generally, in the measurement of trace components, the measurement peak may be hidden in the baseline noise. Therefore, in order to increase the signal / noise ratio, it is necessary to set a long integration time. As a result, even without using a powerful radiation source, trace detection is in principle possible with a normal XRD analyzer. In the invention described in this embodiment, a long-time measurement that fully takes this into account is performed, and analysis is carried out based on the calibration curve created through precise baseline evaluation. As a result, crystalline silica or asbestos is dissolved and removed from the aqueous material, and the asbestos content is truly reduced to 0.1% by weight or less. That is, while conforming to the determination result by a general-purpose X-ray diffractometer as stipulated in the annex to Kikan-Hokatsu No. 0828001, it is confirmed that the safety standard in the annex is achieved with sufficient accuracy by making full use of precise analysis methods.

[0128] Also, whether the product is a silicate mineral powder shall be determined from the diffraction peaks in powder X-ray diffraction. For example, whether the product is magnesium silicate hydrate powder (talc powder) shall be determined by whether there are diffraction peaks at diffraction angles (2θ) of 9.45°, 18.97°, and 28.62° in the powder X-ray diffraction using the above-described precise analysis method.

[0129] Also, the amount of the NaOH aqueous solution (0.01 M) required in the following method (Shear's method) is preferably 180 μl or more, and more preferably 200 μl or more. (1) Disperse 0.1 g of silicate mineral powder in 10 ml of water. (2) After adding 2 g of NaCl, adjust the pH to 4 or less with dilute hydrochloric acid (0.12 M). (3) Add the NaOH aqueous solution (0.01 M), and after adjusting the pH to 4, measure the required amount of the NaOH aqueous solution (0.01 M) until the pH reaches 9.

[0130] The amount of OH groups on the surface increases by hydrothermally treating natural talc. Also, the amount of OH groups increases as the hydrothermal temperature rises. The presence or absence of hydrothermal treatment also affects wettability. Hydrothermally treating natural talc reduces the contact angle. This means that the wettability has improved, i.e., the hydrophilicity has increased. Thus, it can be said that hydrothermally treating silicate minerals improves the affinity with polar solvents for cosmetics and the compatibility.

[0131] When the silicate mineral obtained by the present invention is magnesium silicate hydrate powder, the magnesium silicate hydrate powder can be used in the fields of plastics (fillers (improvement of rigidity, heat resistance, dimensional stability), crystal nucleating agents), papermaking (filler, pitch control agent, coating agent), paints (extender pigments (adjustment of viscosity and gloss), powder paints), electronic components (laminates, molded products, resist inks, adhesives), ceramics (glazes for ceramics, honeycomb ceramic raw materials), rubber (fillers (improvement of heat resistance, reinforcement, etc.), mold release agents), cosmetics (foundations, body powders, baby powders, eyeshadows, lipsticks), sanitary products (baby powder; prevention of baby's sweat and rash, etc.), pharmaceuticals (excipients for tablets, lubricants, lubricants for medical rubber gloves), food (gum base, manufacturing aids (anti-sticking)), agriculture (anti-caking agents for fertilizers, carriers for agricultural chemicals), etc. In particular, since it has high safety at a level corresponding to synthetic talc, the magnesium silicate hydrate powder obtained by the present invention is preferably applied in the fields of cosmetics, sanitary products, pharmaceuticals, and / or food.

[0132] For example, when applied in the field of cosmetics, the cosmetic composition may contain, in addition to the silicate mineral of the present invention, various components exemplified by colorants, extender pigments, brighteners, oily components, moisturizers, surfactants, thickeners, preservatives, ultraviolet light scattering agents, antioxidants, and chelating agents, as needed.

[0133] Examples of colorants include, but are not limited to, inorganic pigments, organic pigments, dyes, natural pigments, etc.

[0134] Examples of the extender pigment include, but are not limited to, inorganic powders such as silica, mica, synthetic fluorophlogopite, glass powder, barium sulfate, kaolin, bentonite, hectorite, zeolite, bismuth oxychloride, zirconium oxide, magnesium oxide, aluminum oxide, calcium sulfate, barium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, and talc. Further, silicone elastomers such as nylon, polyethylene, (vinyldimethylsilicone / methylconsilsesquioxane) copolymer, polymethyl methacrylate, lauroyl lysine, silk powder, cellulose powder, dispersants such as polyvalent metal salts of long-chain fatty acids, and organic powders such as various wax powders, etc. are included, but not limited thereto."

[0135] Examples of the brightening agent include, but are not limited to, those in which the surface of plate-like powders such as mica, synthetic fluorophlogopite, glass, silica, and alumina is coated with a colorant such as titanium oxide, iron oxide, silicon oxide, ultramarine, chromium oxide, tin oxide, chromium hydroxide, gold, silver, carmine, organic pigments such as Red No. 202 and Yellow No. 4, and those obtained by cutting film blanks such as polyethylene terephthalate / polymethyl methacrylate laminate powder, polyethylene terephthalate / aluminum vapor-deposited powder, and polyethylene terephthalate / gold vapor-deposited laminate powder into arbitrary shapes, etc."

[0136] As the oily component, for example, hydrocarbon oil, ester oil, wax, higher alcohol, animal and vegetable oils, etc. can be used. Examples of hydrocarbon oil include squalane, dodecane, tetradecane, hexadecane, etc. Examples of ester oil include phytosteryl macadamia nut fatty acid, octyldodecyl myristate, glyceryl tri(caprylate / caprate), stearyl stearate, methylheptyl isostearate, hexyl laurate, isoacyl laurate, (capric acid / caprylic acid) palm alkyl, isocetyl myristate, isostearyl isostearate, etc. Examples of wax include beeswax, candelilla wax, carnauba wax, rice bran wax, sunflower seed wax, candelilla wax, bayberry wax, montan wax, etc. Examples of higher alcohol (monohydric alcohol having 6 or more carbon atoms) include cetyl alcohol, stearyl alcohol, isostearyl alcohol, lauryl alcohol, behenyl alcohol, etc. Examples of animal and vegetable oils include avocado oil, linseed oil, almond oil, olive oil, cocoa butter, sesame oil, wheat germ oil, safflower oil, jojoba oil, phytosteryl macadamia nut fatty acid, shea butter, turtle oil, camellia oil, persic oil, castor oil, grape oil, macadamia nut oil, coconut oil, rose hip oil, soybean oil, egg yolk oil, hydrogenated castor oil, hydrogenated coconut oil, hydrogenated cocoa butter, hydrogenated turtle oil, hydrogenated mink oil, beef tallow, mink oil, lanolin (wool fat), and oily components extracted from these components, but are not limited thereto.

[0137] As the humectant, for example, polyhydric alcohols such as glycerin, 1,3-butylene glycol, propylene glycol, polyethylene glycol, diglycerin trehalose; high molecular compounds such as sodium hyaluronate, heparin-like substances, sodium chondroitin sulfate, collagen, elastin, keratin, chitin, chitosan; amino acids such as glycine, aspartic acid, arginine; natural moisturizing factors such as sodium lactate, urea, sodium pyrrolidone carboxylate; lipids such as ceramide, cholesterol, phospholipid; plant extract extracts such as chamomile extract, witch hazel extract, tea extract, perilla extract, etc., but are not limited thereto.

[0138] As the surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant can be used. For example, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, monocetyl glyceryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene derivatives such as polyoxyalkyl allyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene hydrogenated castor oil, and polyoxyethylene lanolin; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monooleate, sorbitan sesquioleate, and sorbitan monostearate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monooleate; polyoxyethylene sorbitol fatty acid esters such as polyoxyethylene sorbitol tetraoleate; polyethylene glycol fatty acid esters such as polyethylene glycol monolaurate and polyethylene glycol monooleate; alkyl glyceryl ethers such as isostearyl glyceryl ether; and glycerin fatty acid esters such as glyceryl monobehenate. One or more selected from these can be mentioned. Anionic surfactants such as fatty acid monocarboxylates, polyoxyethylene alkyl ether acetates, alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, stearoyl methyl taurine and its salts; amphoteric surfactants such as fatty acid amide propyl betaine, alkyl imidazolium betaine, alkyl dimethylamino acetic acid betaine, alkyl dimethyl sulfobetaine, alkyl dimethyl amine oxide, and alkyl hydroxy sulfobetaine. One or more selected from these can be mentioned, but are not limited thereto.

[0139] Examples of thickeners include, but are not limited to, guar gum, locust bean gum, carrageenan, xanthan gum, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydrophobized hydroxypropyl methyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, carboxyvinyl polymer, acrylic acid methacrylic acid alkyl copolymer, polyethylene glycol, bentonite, (hydroxyethyl acrylate / sodium acryloyldimethyltaurate) copolymer, (ammonium acryloyldimethyltaurate / vinyl pyrrolidone) copolymer, etc.

[0140] Examples of preservatives include, but are not limited to, benzoic acid, sodium benzoate, dehydroacetic acid, sodium dehydroacetate, isobutyl paraoxybenzoate, isopropyl paraoxybenzoate, butyl paraoxybenzoate, ethyl paraoxybenzoate, propyl paraoxybenzoate, benzyl paraoxybenzoate, methyl paraoxybenzoate, phenoxyethanol, chlorobutanol, chlorhexidine, salicylic acid, benzalkonium chloride, cetyltrimethylammonium bromide, acrinol, benzethonium chloride, cresol, gluconic acid and its derivatives, povidone iodine, potassium iodide, iodine, isopropylmethylphenol, triclocarban, triclosan, photosensitizer No. 101, photosensitizer No. 201, parabens, phenoxyethanol, 1,2-pentanediol, alkyl diamino glycine hydrochloride, pyrithione zinc, miconazole, etc.

[0141] Examples of the ultraviolet absorber include, but are not limited to, para-aminobenzoic acid, glyceryl para-aminobenzoic acid, ethyl dihydroxypropyl para-aminobenzoic acid, octyl dimethyl para-aminobenzoic acid, amyl para-dimethylaminobenzoate, hexyl diethylaminohydroxybenzoyl benzoate, methyl anthranilate, homomenthyl salicylate, 2-ethylhexyl salicylate, triethanolamine salicylate, 2-ethylhexyl paramethoxycinnamate, glyceryl diparamethoxycinnamate mono-2-ethylhexanoate, methyl 2,5-diisopropylcinnamate, methyl trimethoxycinnamate bis(trimethylsiloxy)silyl isopentyl, isopropyl paramethoxycinnamate, isopropyl paramethoxycinnamate / diisopropylcinnamate ester mixture, 2-ethoxyethyl paramethoxycinnamate, diethanolamine salt of paramethoxycinnamic acid, 4-isopropyldibenzoylmethane, 4-tert-butyl-4'-methoxydibenzoylmethane, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, 2,4-bis[{4-(2-ethylhexyloxy)-2-hydroxy}-phenyl]-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-(2-β-glucopyranosyloxy)propoxy-2-hydroxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidine propionate, octocrylene, cinoxate, phenylbenzimidazole sulfonic acid, 1-(3,4-dimethoxyphenyl)-4,4-dimethyl-1,3-pentanedione, 3-(4-methylbenzylidene)camphor, methylenebisbenzotriazolyltetramethylbutylphenol, etc.

[0142] Examples of the ultraviolet scattering agent include, but are not limited to, titanium oxide, zinc oxide, cerium oxide, etc.

[0143] Examples of the antioxidant include, but are not limited to, natural vitamin E, tocopherol, dibutylhydroxytoluene, butylhydroxyanisole, sorbic acid, sodium sulfite, ascorbic acid, erythorbic acid, L-cysteine hydrochloride, etc. Examples of the pH adjuster include, but are not limited to, inorganic acids (hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, boric acid, etc.), organic acids (lactic acid, acetic acid, citric acid, sodium citrate, tartaric acid, malic acid, succinic acid, sodium succinate, oxalic acid, gluconic acid, fumaric acid, propionic acid, acetic acid, aspartic acid, ε-aminocaproic acid, glutamic acid, aminoethylsulfonic acid, etc.), gluconolactone, ammonium acetate, inorganic bases (sodium hydrogen carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, etc.), organic bases (monoethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, lysine, etc.).

[0144] Examples of the chelating agent include, but are not limited to, ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetraacetate (sodium salt (sodium edetate: Japanese Pharmacopoeia, EDTA-2Na, etc.), potassium salt, etc.), phytic acid, gluconic acid, polyphosphoric acid, metaphosphoric acid, etc.

[0145] The above-mentioned colorants and extender pigments can be those whose surfaces are treated with a surface treatment agent as required. Examples of the surface treatment agent include, but are not limited to, fluorine compound treatment, silicone treatment, silicone resin treatment, pendant treatment, silane coupling agent treatment, titanium coupling agent treatment, oil agent treatment, metal soap treatment, N-acylation lysine treatment, polyethylene glycol treatment, PVA treatment, polyacrylic acid treatment, hyaluronic acid treatment, alginic acid treatment, inorganic compound treatment, urethane cross-linked polymer treatment, plasma treatment, mechanochemical treatment, etc. Among them, metal soap treatment and urethane cross-linked polymer treatment are preferred. Examples of the metal soap treatment include aluminum dimyristate treatment, aluminum stearate treatment, aluminum distearate treatment, etc. As the urethane cross-linked polymer treatment, (HDI / trimethylolhexyl lactone) cross-polymer treatment can be preferably used.

[0146] Furthermore, heretofore, the formation of minerals underground has been precipitation due to the temperature and pressure, and the precipitate composition varies depending on the location where the minerals are mined. Scrutinizing and selecting the parts containing almost no impurities as described above and using them has been regarded as the only solution. However, according to the present invention, even a raw material containing impurities exceeding the specified value may be able to reduce the impurity content to less than the specified value. In this regard, the present invention has great advantages for processing companies and sales companies of silicate minerals.

[0147] In the present invention, the term "articles containing silicate minerals" means both the case where silicate minerals are contained in the composition and the case where silicate minerals are adhered to the articles. For example, "pharmaceuticals containing silicate minerals" means both the case where silicate mineral powder is contained in a pharmaceutical composition as an excipient or lubricant for tablets and the case where silicate mineral powder is adhered to medical rubber gloves.

Examples

[0148] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[0149]

Table 2

[0150]

Table 3

[0151] <Test Example 1> Hydrothermal Reaction Treatment of Natural Talc Containing Quartz 〔Hydrothermal Reaction Treatment of Natural Talc〕 The test was conducted using a batch tester (device name: Oscillating Reactor Heating Stirring Device, manufactured by AKICO Co., Ltd.). In a 5 ml Inconel container, 0.45 g of natural talc with an average particle size of 5 μm and containing quartz as an impurity (concentration: 10% by weight) and 4 ml of H 2 O were added and mixed well, and then hydrothermally reacted for 10 minutes under the conditions shown in Table 2 using a batch tester. After cooling, the processed talc was obtained by thoroughly washing with water.

[0152] 〔Evaluation〕 When touching the processed talc after the hydrothermal reaction treatment with a finger, it had the same smoothness as the natural talc before the hydrothermal reaction treatment. The average particle size of the processed talc after the hydrothermal reaction treatment was measured. As a result, the average particle size was 5 μm in all examples.

[0153] Also, powder X-ray diffraction was performed on each of the natural talc before the hydrothermal reaction treatment and the processed talc after the hydrothermal reaction treatment. Figure 2 shows the result of the natural talc before the hydrothermal reaction treatment, and Figure 3 shows the result of the processed talc after the hydrothermal reaction treatment according to Example 1-1. Also, Table 3 shows the change in the impurity content before and after the hydrothermal reaction treatment in each example and comparative example. In both Figure 2 and Figure 3, in powder X-ray diffraction, diffraction peaks are present at diffraction angles (2θ) of 9.45°, 18.97°, and 28.62°. Therefore, it means that the substance after the hydrothermal reaction treatment is talc.

[0154] On the one hand, in the vicinity of 2θ = 26.6°, before the hydrothermal reaction treatment, a peak derived from quartz (crystalline silica) appears. From the calibration curve obtained using a standard quartz sample, the talc before the hydrothermal reaction treatment contains 0.11 wt% of quartz, while there is no alteration even after the hydrothermal reaction treatment, and on the other hand, the peak derived from quartz has disappeared. That is, in Example 1-1, it was confirmed that quartz could be sufficiently removed.

[0155] Similarly, in Examples 1-2 to 1-13, it was also confirmed that quartz could be sufficiently removed from natural talc. In particular, in Examples 1-10 to 1-13, it was confirmed that quartz could be sufficiently removed from natural talc even if it had a relatively high impurity content. Also, in Examples 1-6 and 1-7, it was confirmed that quartz could be sufficiently removed from natural talc even when the natural talc concentration in the hydrothermal reaction treatment was relatively high.

[0156] <Test Example 2> Hydrothermal reaction treatment of natural talc containing quartz (pH dependence) Processed talc was obtained in the same manner as in Example 1-1, except that nitric acid and sodium hydroxide were used to adjust the pH during hydrothermal treatment to 1.4 (Example 2-1), 2.5 (Example 2-2), 6.4 (Example 2-3), and 12.0 (Comparative Example 2).

[0157] As a result of the evaluation by XRD, a decrease and disappearance of the peak derived from quartz were confirmed in the products obtained during hydrothermal treatment at pH 1.4, 2.5, and 6.4. On the other hand, it was confirmed that the peak derived from quartz remained in the product obtained during hydrothermal treatment at pH 12.0. Since the pH was 9.4 in Example 1-1, it was confirmed that quartz could be removed at pH values below that, and conversely, quartz could not be removed if the pH was too high.

[0158] In addition, when the average particle diameter of the primary particles was measured for the products obtained at pH 1.4, 2.5, and 6.4, it was 5 μm in all cases.

[0159] <Test Example 3> Hydrothermal reaction treatment of natural talc containing quartz (addition of Mg ions) 0.06 g of natural talc (concentration: 1.5% by weight) and MgCl 2 : 3 mg (concentration 0.075% by weight) and H 2 4 ml of O were added to an Inconel container, and processed talc was obtained in the same manner as in Example 1-1 except that the hydrothermal reaction time was 240 minutes.

[0160] As a result of the evaluation by XRD, a decrease in the peak derived from quartz was confirmed. Even for natural talc with a relatively high impurity content similar to that of Example 1-5, the same amount of quartz could be reduced even when the hydrothermal reaction temperature was 150°C.

[0161] <Test Example 4> Hydrothermal reaction treatment of natural talc containing impurities different from quartz 〔Example 4-1〕 Hydrothermal reaction treatment of natural talc containing cristobalite Processed talc was obtained in the same manner as in Example 1-1 except that natural talc containing 0.12% by weight of cristobalite, which is a type of crystalline silica, was used as the raw material.

[0162] As a result of the evaluation by XRD, the peak at a diffraction angle (2θ) of 22.0° derived from cristobalite disappeared, and it was confirmed that the content of cristobalite could be reduced to 0.1% by weight or less by the hydrothermal reaction treatment.

[0163] 〔Example 4-2〕 Hydrothermal reaction treatment of natural talc containing tridymite Processed talc was obtained in the same manner as in Example 1-1 except that natural talc containing 0.12% by weight of tridymite, which is a type of crystalline silica, was used as the raw material.

[0164] As a result of the evaluation by XRD, the peaks at diffraction angles (2θ) of 20.5° and 21.6° derived from tridymite disappeared, and it was confirmed that the content of tridymite could be reduced to 0.1% by weight or less by the hydrothermal treatment.

[0165] 〔Examples 4-3 to 4-5〕 Hydrothermal reaction treatment of natural talc containing chrysotile Except that natural talc containing 0.15% by weight of chrysotile was hydrothermally treated at 250 °C for 10 minutes, 40 minutes, and 120 minutes, processed talc was obtained in the same manner as in Example 1-1.

[0166] As a result of the evaluation by XRD, the chrysotile content was 0.075% by weight (treatment time: 10 minutes), 0.03% by weight (treatment time: 40 minutes), and below the detection limit (treatment time: 120 minutes). It was confirmed that the chrysotile content could be reduced to 0.1% by weight or less by the hydrothermal reaction treatment.

[0167] Generally, chrysotile is a stable substance, but under hydrothermal conditions, dissolution tends to proceed from the tip of the acicular mineral more easily than in ordinary minerals. However, even if it dissolves, the talc may also dissolve. Therefore, what is important is the dissolution rate, the amount of dissolution, the ratio of the amount of dissolution of talc, and the amount remaining as a result. Considering the dissolution rate and the amount of dissolution of a large amount of silicate minerals, even if the same amount dissolves, it is possible to finally leave only magnesium silicate. This result shows that a sufficient dissolution and removal effect of chrysotile is observed, indicating that it is possible to remove the asbestos component from talc.

[0168] <Test Example 5> Hydrothermal reaction treatment of silicate minerals different from natural talc 〔Example 5-1〕 Hydrothermal reaction treatment of magnesium aluminum silicate containing quartz Except that magnesium aluminum silicate containing 0.12% by weight of quartz was used as the raw material, processed minerals were obtained in the same manner as in Example 1-1.

[0169] As a result of the evaluation by XRD, since the diffraction peak derived from quartz decreased, it was confirmed that the quartz content could be reduced to 0.04% by weight by hydrothermal treatment.

[0170] 〔Example 5-2〕 Hydrothermal reaction treatment of calcium silicate containing quartz Except that calcium silicate containing 0.12% by weight of quartz was used as the raw material, processed minerals were obtained in the same manner as in Example 1-1.

[0171] As a result of the evaluation by XRD, since the diffraction peaks derived from quartz decreased, it was confirmed that the content of quartz could be reduced to 0.04% by weight by hydrothermal treatment.

[0172] 〔Examples 5-3 to 5-4〕 Hydrothermal reaction treatment of magnesium silicate containing quartz Processed minerals were obtained by the same method as in Example 1-1 except that magnesium silicate containing 0.12% by weight of quartz was used as the raw material (the treatment times were 10 minutes and 40 minutes).

[0173] As a result of the evaluation by XRD, since the diffraction peaks derived from quartz disappeared, it was confirmed that the content of quartz could be reduced to 0.01% by weight (treatment time: 10 minutes) and below the detection limit (treatment time: 120 minutes) by hydrothermal treatment.

[0174] <Test Example 6> Relationship between hydrothermal treatment temperature, amount of OH groups on the talc surface, and wettability

Table 4

Table 5

[0175] Processed minerals were obtained by the same method as in Example 1-1 except that the conditions described in Table 4 were used.

[0176] 〔Amount of OH groups on the talc surface〕 The amount of OH groups on the talc surface was evaluated using the Shears method. Specifically, the following procedure was performed. (1) 0.1 g of the processed mineral was dispersed in 10 ml of water. (2) After adding 2 g of NaCl, the pH was adjusted to 4 or less with dilute hydrochloric acid (0.12 M). (3) An aqueous NaOH solution (0.01 M) was added, and after adjusting the pH to 4, the required amount from there until the pH reached 9 was examined.

[0177] The results are shown in Table 5. It was confirmed that the amount of OH groups on the surface increased by hydrothermally treating natural talc, and the amount of OH groups increased with the increase in hydrothermal temperature.

[0178] 〔Wettability〕 For each of Example 6-2 and Comparative Example 6, talc was uniformly supported on an X-ray diffraction sample holder. Then, a single drop (10 μl) of water was dropped, and the contact angle was observed.

[0179] The results are shown in Table 5. The contact angle slightly decreased by hydrothermally treating natural talc. This means that the wettability improved, that is, the hydrophilicity improved. Thus, it can be said that by hydrothermally treating the silicate mineral, the affinity with the polar solvent for cosmetics is improved and the compatibility is improved.

[0180] <Test Example 7> Application to Makeup Cosmetics 〔Test Example 7-1〕 Application to Powder Foundation A powder foundation was prepared according to the formulation shown in Table 6. In Example 7-1, the hydrothermally treated talc obtained in Example 1-1 was used as talc. In Comparative Example 7-1, natural talc before the hydrothermal treatment according to Example 1-1 was used as talc.

Table 6

[0181] For the obtained powder foundation, the slurry state, hardness, drop strength, and pick-up amount were evaluated. As a result, it was confirmed that the powder foundation using the hydrothermally treated talc had the same quality as the powder foundation using the non-hydrothermally treated natural talc.

[0182] 〔Test Example 7-2〕 Application to Loose Powder Loose powder was prepared according to the formulation shown in Table 7. In Example 7-2, the hydrothermally treated talc obtained in Example 7-1 was used as the talc. In Comparative Example 7-2, natural talc before hydrothermal treatment according to Example 1-1 was used as the talc.

Table 7

[0183] For the obtained loose powder, the slurry state, hardness, dropping strength, and yield were evaluated. As a result, it was confirmed that the loose powder using hydrothermally treated talc had the same quality as the loose powder using non-hydrothermally treated natural talc.

[0184] 〔Test Example 7-3〕 Application to eye blow Two types of eye blows were prepared according to the formulation shown in Table 8. In Examples 7-3-1 and 7-3-2, the hydrothermally treated talc obtained in Example 1-1 was used as the talc. In Comparative Examples 7-3-1 and 7-3-2, natural talc before hydrothermal treatment according to Example 1-1 was used as the talc.

Table 8

[0185] For the obtained eye blow, the slurry state and the dropping strength were evaluated. As a result, it was confirmed that the eye blow using the hydrothermally treated talc had the same quality as the eye blow using the natural talc without hydrothermal treatment.

[0186] <Test Example 8> Application to Skin Care Cosmetics 〔Test Example 8-1〕 Application to Summer Body Lotion A summer body lotion was prepared according to the formulation shown in Table 9. In Example 8-1, the hydrothermally treated talc obtained in Example 1-1 was used as the talc. In Comparative Example 8-1, the natural talc before the hydrothermal treatment according to Example 1-1 was used as the talc.

Table 9

[0187] For the obtained summer body lotion, the slurry state was evaluated. As a result, it was confirmed that the summer body lotion using the hydrothermally treated talc had the same quality as the summer body lotion using the natural talc without hydrothermal treatment.

[0188] 〔Test Example 8-2〕 Application to Pore Concealer Lotion A pore concealer lotion was prepared according to the formulation shown in Table 10. In Example 8-2, the hydrothermally treated talc obtained in Example 1-1 was used as the talc. In Comparative Example 8-2, the natural talc before the hydrothermal treatment according to Example 1-1 was used as the talc.

Table 10

[0189] The resulting pore concealer lotion was evaluated for its slurry state. As a result, it was confirmed that the pore concealer lotion using hydrothermally treated talc had the same quality as the pore concealer lotion using non-hydrothermally treated natural talc.

[0190] [Test Example 8-3] Application to Powder Facial Wash A powder facial wash was prepared according to the formulation shown in Table 11. In Example 8-3, the hydrothermally treated talc obtained in Example 1-1 was used as the talc. In Comparative Example 8-3, natural talc before the hydrothermal treatment according to Example 1-1 was used as the talc. [Table 11] (※) Example 8-3: Talc = Hydrothermally treated talc obtained in Example 1-1 Comparative Example 8-3: Talc = Natural talc before the hydrothermal treatment according to Example 1-1

[0191] The resulting powder facial wash was evaluated for its slurry state. As a result, it was confirmed that the powder facial wash using hydrothermally treated talc had the same quality as the powder facial wash using non-hydrothermally treated natural talc. [Explanation of Signs]

[0192] 1 Manufacturing apparatus 10 Extraction means 20 Cooling means

Claims

1. The content of crystalline silica and asbestos is each 0.1% by weight or less, A silicate mineral powder intended for use in one or more of cosmetics, hygiene products, pharmaceuticals, and foods, wherein the amount of NaOH aqueous solution (0.01 M) required in the following procedure is 180 μl or more. (1) Disperse 0.1 g of silicate mineral powder in 10 ml of water. (2) Add 2 g of NaCl and then adjust the pH to 4 or less with dilute hydrochloric acid (0.12 M). (3) Add an aqueous NaOH solution (0.01 M) until the pH reaches 4, and then measure the amount of aqueous NaOH solution (0.01 M) required to reach a pH of 9.

2. 2. The silicate mineral powder according to claim 1, which contains carbonate.

3. 2. The silicate mineral powder according to claim 1, wherein the average particle size of the primary particles is 100 nm or more.

4. A cosmetic comprising the silicate mineral powder according to any one of claims 1 to 3.

5. A sanitary product comprising the silicate mineral powder according to any one of claims 1 to 3.

6. A pharmaceutical product comprising the silicate mineral powder according to any one of claims 1 to 3.

7. A food product comprising the silicate mineral powder according to any one of claims 1 to 3.

8. The method comprises the step of subjecting a silicate mineral derived from a natural mineral to a hot water or hot water treatment or a hydrothermal reaction treatment at a pH of 4 to 9.4, The temperature in the warm water or hot water treatment or the hydrothermal reaction treatment is 100°C or higher and 370°C or lower, the pressure is equal to or higher than the saturated vapor pressure of water, and the treatment time is 1 minute or higher and 10 hours or lower. A method for producing silicate mineral powder for use in one or more products selected from the group consisting of cosmetics, hygiene products, pharmaceuticals, and foods.

9. The hot water treatment or the hydrothermal reaction treatment is carried out using carbon dioxide or CO ２ The method according to claim 8, wherein the method is carried out in the presence of

10. The method according to claim 8 , wherein the warm water or hot water treatment or the hydrothermal reaction treatment is carried out in the coexistence of Mg ions.

11. The method according to claim 8, wherein the hot water or hot water treatment or the hydrothermal reaction treatment is carried out using a batch or semi-batch apparatus.

12. The reactor is a semi-batch reactor, The method according to claim 11, wherein the amount of the aqueous solvent supplied to the semi-batch apparatus is 0.1 times or more of the theoretical amount required for saturating the crystalline silica contained in the silicate mineral as the raw material in the reaction solution containing the coexisting ions in the reaction field.

13. The reactor is a semi-batch reactor, The method according to claim 11 or 12, wherein the amount of crystalline silica contained in the silicate mineral as the raw material charged to the semi-batch apparatus is 10 times or less of the theoretical amount that is saturated and dissolved in the reaction solution containing the coexisting ions of the reaction field.

14. The method according to claim 8, wherein the silicate mineral is supplied in a suspended state in water using a flow-through device, and the hot water treatment, the hot water treatment, or the hydrothermal reaction treatment is carried out.

15. The method according to claim 14, wherein the concentration of the silicate mineral water slurry supplied to the flow-through device is 0.1 times or more of the theoretical amount at which the crystalline silica contained in the silicate mineral as the raw material is saturated and dissolved in the reaction solution containing the coexisting ions in the reaction field.

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