Method for estimating allophane content in volcanic deposit and method for producing hydraulic composition

Abstract

To provide a method capable of rapidly estimating the allophane content in volcanic deposits.SOLUTION: The method for estimating the allophane content contained in volcanic deposits includes an estimation step of estimating allophane content contained in the volcanic deposits by using at least one measurement value selected from the group consisting of SiO2 content of the volcanic deposits, Al2O3 content, Na2O content, K2O content, R2O content, hydration heat, BET specific surface area, ion ratio of Fe3+ to the total amount of Fe3+ and Fe2+, a value in the Lab color system, and b value in the Lab color system.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for estimating the allophane content contained in a volcanic ejecta deposit and a method for producing a hydraulic composition. [Background technology]

[0002] Volcanic ejecta deposits are an abundant material in Japan, and volcanic glass contained in volcanic ash is used as an admixture for concrete. Weathering of volcanic ejecta deposits produces clay minerals such as allophane and halloysite. However, the proportion of clay minerals contained in volcanic ejecta deposits varies from one volcanic ejecta deposit to another. The acid-alkali alternating dissolution method is known as a method for quantifying allophane contained in volcanic ejecta deposits (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Yasuo Kitagawa, "Study on the Quantitative Analysis of Allophane and Amorphous Inorganic Components in Soil," Report of the National Institute of Agricultural Sciences, Soil and Fertilizer, No. 29, pp. 1-48 (1977) Summary of the Invention [Problem to be solved by the invention]

[0004] Quantifying allophane using the acid-alkali alternating dissolution method requires multiple cycles of elution of allophane and the like with acid, elution of allophane and the like with alkali, drying of the sample, and weight analysis, requiring a considerable number of analysis days. Therefore, one aspect of the present disclosure provides an estimation method that can quickly estimate the allophane content contained in volcanic ejecta deposits. Another aspect of the present disclosure provides a method for producing a hydraulic composition that can quickly adjust the allophane content. [Means for solving the problem]

[0005] One aspect of the present disclosure is a method for estimating the allophane content contained in a deposit of volcanic ejecta, the method comprising: determining the SiO content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe in the deposit of the volcanic ejecta; 3+ and Fe 2+ Fe relative to the total amount of 3+ and estimating the allophane content in the deposit of volcanic ejecta using at least one measured value selected from the group consisting of an ion ratio of 1 to 2, an a value in the Lab color system, and a b value in the Lab color system.

[0006] The above estimation method uses the following parameters: SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe 3+ and Fe 2+ Fe relative to the total amount of 3+ At least one measured value selected from the group consisting of the ion ratio, the a value in the Lab color system, and the b value in the Lab color system is used. Each of these measured values ​​can be obtained more quickly than by actually measuring the allophane content. Therefore, the above estimation method allows the allophane content to be estimated quickly.

[0007] One aspect of the present disclosure provides a method for producing a hydraulic composition, which includes a blending step of blending at least volcanic ejecta deposits and an alkaline activator as raw materials, wherein in the blending step, the blending ratio of the raw materials is adjusted based on the estimated value of the allophane content contained in the volcanic ejecta deposits derived by the above-mentioned estimation method.

[0008] In the above-described manufacturing method, the mixing ratio of the raw materials is adjusted using the estimated value of the allophane content derived by the above-described estimation method, and therefore the allophane content in the hydraulic composition can be quickly adjusted. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, it is possible to provide an estimation method that can quickly estimate the allophane content contained in a deposit of volcanic ejecta. According to another aspect of the present disclosure, it is possible to provide a manufacturing method of a hydraulic composition that can quickly adjust the allophane content. [Brief explanation of the drawings]

[0010] [Figure 1] Figures 1(A) and (B) are graphs showing the measurement results of the hydration heat rate and integrated value of the hydration heat value of volcanic ejecta deposits. [Figure 2] Figure 2 is a graph showing the correlation between the allophane content (measured value) of volcanic ejecta deposits and the various property values ​​of volcanic ejecta deposits (SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, and calorific value of hydration). [Figure 3] Figure 3 is a graph showing the correlation between the allophane content (measured value) of volcanic ejecta deposits and various property values ​​of volcanic ejecta deposits (BET specific surface area, a value in the Lab color system, b value in the Lab color system, and the ion ratio of Fe3+ to the sum of Fe3+ and Fe2+ (T-Fe)). [Figure 4] Figures 4(A) to (F) are graphs showing the correlation between the allophane content (measured value) in volcanic ejecta deposits and the allophane content (estimated value) estimated from each multiple regression equation shown in Table 4. [Figure 5] Figures 5(A) to (F) are graphs showing the correlation between the allophane content (measured value) in volcanic ejecta deposits and the allophane content (estimated value) estimated from each multiple regression equation shown in Table 4. [Figure 6] Figures 6(A) to (F) are graphs showing the correlation between the allophane content (measured value) in volcanic ejecta deposits and the allophane content (estimated value) estimated from each multiple regression equation shown in Table 4. [Figure 7] 7(A) to (F) are graphs showing the correlation between the allophane content (measured value) in volcanic ejecta deposits and the allophane content (estimated value) estimated from each multiple regression equation shown in Table 4. [Figure 8]8(A) to (E) are graphs showing the correlation between the allophane content (measured value) in volcanic ejecta deposits and the allophane content (estimated value) estimated from each multiple regression equation shown in Table 4. [Figure 9] Fig. 9 is a graph plotting the relationship between the allophane content of a hydraulic composition determined from the allophane content (actually measured value) of volcanic ejecta deposits and the ratio of compressive strength (strength ratio) of a set body of the hydraulic composition to a set body of a hydraulic composition containing only an alkali activator, for each material age. Fig. 9(A) shows data when the content of volcanic ejecta deposits or limestone in the hydraulic composition is 10% by mass, Fig. 9(B) shows data when the content of volcanic ejecta deposits or limestone in the hydraulic composition is 30% by mass, and Fig. 9(C) shows data when the content of volcanic ejecta deposits or limestone in the hydraulic composition is 50% by mass. [Figure 10] Fig. 10 is a graph plotting the relationship between the allophane content of a hydraulic composition determined from the allophane content (measured value) of volcanic ejecta deposits and the ratio of compressive strength (strength ratio) of a hardened body of the hydraulic composition to a hardened body of a hydraulic composition containing only an alkali activator and limestone, for each material age. Fig. 10(A) shows data when the content of volcanic ejecta deposits or limestone is 10% by mass, Fig. 10(B) shows data when the content of volcanic ejecta deposits or limestone is 30% by mass, and Fig. 10(C) shows data when the content of volcanic ejecta deposits or limestone is 50% by mass. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. The symbol "to" used in a numerical range indicates a numerical range that includes the upper and lower limit values. For example, "X to Y" indicates a numerical range "greater than or equal to X and less than or equal to Y." Numerical ranges in which the upper and / or lower limits are replaced with numerical values ​​described in the examples are also included in the content of the present disclosure. Multiple exemplified components or materials may be used alone or in combination.

[0012] In the present specification, numerical ranges in which the upper or lower limit of one numerical range is replaced with the upper or lower limit of another numerical range are also included in the present disclosure. In the present specification, numerical ranges in which the upper or lower limit of a numerical range is replaced with a value shown in the examples are also included in the present disclosure.

[0013] According to one embodiment, a method for estimating the allophane content contained in a volcanic ejecta deposit includes measuring the SiO content, Al2O3 content, Na2O content, K2O content, and R2O content of the volcanic ejecta deposit, the calorific value of hydration, the BET specific surface area, and Fe 3+ and Fe 2+ Fe relative to the total amount of 3+ The method further comprises an estimation step of estimating the allophane content in the deposit of volcanic ejecta using at least one measured value selected from the group consisting of the ion ratio of

[0014] The volcanic ejecta deposits may be obtained from stratum deposited during a volcanic eruption. The stratum may contain at least one of volcanic ash, volcanic lapilli, pumice, pyroclastic flow deposits, and the like. The volcanic ejecta deposits may also be natural deposits that have been pretreated by sieving, calcination, or the like. The volcanic ejecta deposits may or may not contain allophane. The above estimation method may be used to distinguish between volcanic ejecta deposits that contain allophane and volcanic ejecta deposits that do not contain allophane.

[0015] Allophane is a mineral formed by the long-term weathering and hydrothermal alteration of volcanic ash and feldspar in volcanic deposits. For example, it has a hollow spherical structure with a particle size of 0.05 to 0.2 μm, and the outer part of the hollow sphere (shell) has an octahedral sheet of Al2O3, and the inner part of the hollow sphere (shell) has a tetrahedral sheet of SiO2.

[0016] The volcanic ejecta deposits used in this embodiment may be natural products, or may have been pretreated to such an extent that all of the allophane is not altered into other minerals. Examples of pretreatment include particle size adjustment and calcination. Calcination may be performed, for example, by heating in an inert gas atmosphere such as nitrogen gas at 500 to 900°C for 1 to 4 hours. Such pretreatment can sufficiently preserve the allophane contained in the volcanic ejecta deposits while increasing the strength of the hydraulic composition obtained by blending the volcanic ejecta deposits with the alkaline activator. The volcanic ejecta deposits may be commercially available products, or may be commercially available products that have been pretreated as described above. Examples of commercially available products include Kanuma soil, Satsuma soil, Kuroboku soil, and SEKADO P-1 (trade name, manufactured by Shinagawa General Co., Ltd.).

[0017] The SiO2 content of the volcanic ejecta deposits may be 30 to 80 mass%, or 35 to 75 mass%. The Al2O3 content of the volcanic ejecta deposits may be 5 to 45 mass%, or 10 to 40 mass%. The Na2O content of the volcanic ejecta deposits may be 0.1 to 5 mass%, or 0.3 to 4 mass%. The K2O content of the volcanic ejecta deposits may be 0.1 to 5 mass%, or 0.2 to 4 mass%. The R2O content of the volcanic ejecta deposits may be 0.1 to 10 mass%, or 0.4 to 8 mass%. The R2O content in this disclosure is the alkali content, calculated as the Na2O content + 0.658K2O content. The contents of these chemical components can be determined by quantifying each metal element by X-ray fluorescence analysis and converting it to its oxide. When volcanic deposits weather, they tend to have low SiO2, Na2O, K2O, and R2O contents, and high Al2O3 contents.

[0018] The calorific value of hydration of volcanic ejecta deposits can be measured with a commercially available conduction calorimeter using a sample prepared by mixing the volcanic ejecta deposits and water in a 1:1 mass ratio. The calorific value of hydration may be, for example, the integrated value over one hour (integrated calorific value). This reduces the variability of the measurement value, allowing the allophane content to be estimated with sufficiently high accuracy.

[0019] The integrated value (1 hour) of the calorific value of hydration of volcanic ejecta deposits measured by the above-mentioned procedure may be 0 to 50 J / g, or 0 to 40 J / g. In this disclosure, [J / g] refers to the calorific value per 1 g of volcanic ejecta deposits. Volcanic ejecta deposits with a high calorific value of hydration tend to have a high allophane content.

[0020] The BET specific surface area of ​​volcanic ejecta deposits can be measured using a commercially available measuring device, for example, by the nitrogen adsorption method. The BET specific surface area of ​​volcanic ejecta deposits is in the range of 5 to 500 m. 2 / g, or 8 to 300m 2 / g.

[0021] Volcanic deposits may contain iron compounds. Examples of iron compounds containing divalent iron ions include FeO. Examples of iron compounds containing trivalent iron ions include Fe2O3. Among the iron ions that make up iron compounds, Fe 2+ and Fe 3+ Fe relative to T-Fe, which is the sum of 3+ Percentage of Fe 3+ / T-Fe) has a high correlation with the allophane content. 3+ / T-Fe) may be 0.1 to 2, 0.2 to 1.5, or 0.2 to 1.0. 3+ / Fe 2+ may be 0.1 to 10, or 0.2 to 8.

[0022] Fe in volcanic deposits 3+ and Fe 2+ The Fe content may be measured by spectrophotometry, Mössbauer spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, or X-ray absorption fine structure analysis. When volcanic deposits are weathered, the Fe content increases. 3+ Percentage of Fe 3+ / T-Fe) tends to increase.

[0023] The a value in the Lab color system of volcanic ejecta deposits may be 0.1 to 10, or 0.3 to 8. The b value in the Lab color system of volcanic ejecta deposits may be 1 to 20, or 3 to 18. Minerals containing Fe(III) ions are often yellowish-brown, while minerals containing Fe(II) ions are often light green. The a value in the Lab color system is thought to be related to the content of Fe(III) ions. The a value and b value in the Lab color system of the present disclosure can be measured using a commercially available spectrocolorimeter according to the method of Hunter 1948.

[0024] A regression equation creation step may be provided before the estimation step, and a regression equation created using measurements of volcanic ejecta deposits for creating the regression equation may be used. The regression equation may be a simple regression equation or a multiple regression equation. The regression equation in the present disclosure includes both simple regression equations and multiple regression equations. The explanatory variables include the above-mentioned SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe 3+ and Fe 2+ Fe relative to the total amount of 3+ At least one measured value selected from the group consisting of the ion ratio, the a value in the Lab color system, and the b value in the Lab color system can be used. If one measured value is used as the explanatory variable, a simple regression equation can be obtained. If two or more measured values ​​are used as explanatory variables, a multiple regression equation can be obtained. By using a multiple regression equation, the allophane content in the volcanic ejecta deposit to be estimated can be estimated with even higher accuracy. The dependent variable may be a measured value of the allophane content in the volcanic ejecta deposit used to create the regression equation. The measured value of the allophane content may be determined, for example, by an acid-alkali alternating dissolution method.

[0025] The properties of the volcanic deposits used to create the regression equation (SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe 3+ and Fe 2+ Fe relative to the total amount of 3+The numerical ranges of the measured values ​​and the measurement methods for the ion ratio, the a value in the Lab color system, and the b value in the Lab color system) may be the same as those for the volcanic ejecta deposits described above, or may be different. If a volcanic ejecta deposit with similar properties to the target volcanic ejecta deposit is used to create the regression equation, the allophane content in the target volcanic ejecta deposit can be estimated with even greater accuracy. Furthermore, if the measurement methods for each property are the same, the allophane content in the target volcanic ejecta deposit can be estimated with even greater accuracy.

[0026] The regression equation creation step and estimation step may be performed using a conventional calculator or computer. Each measurement value of the volcanic ejecta deposit used to create the regression equation is input into the computer, and the regression equation is derived using software. The regression equation may be stored in a memory unit of the computer, and measurement values ​​of each property of the volcanic ejecta deposit that is the estimation target may be input into the computer so that an estimated value of the allophane content in the volcanic ejecta deposit that is the estimation target is output.

[0027] According to the estimation method of this embodiment, the allophane content of volcanic ejecta deposits can be estimated based on the above-mentioned properties. Therefore, the allophane content, which previously required several days to 10 days for measurement, can be quickly estimated.

[0028] A method for producing a hydraulic composition according to one embodiment includes a blending step of blending at least volcanic ejecta deposits and an alkaline activator as raw materials, and in the blending step, the blending ratio of the raw materials is adjusted based on the estimated allophane content contained in the volcanic ejecta deposits derived by the above-described allophane content estimation method. This manufacturing method can quickly adjust the allophane content in the hydraulic composition. Therefore, a hydraulic composition with reduced variation in the allophane content can be obtained.

[0029] Examples of raw materials include deposits of volcanic ejecta and alkali stimulants. Examples of deposits of volcanic ejecta include those described above. Examples of alkali stimulants include Portland cement clinker, Portland cement, tricalcium silicate (3CaO·SiO 2、 represented by C3S), slaked lime, alkali carbonate, etc.

[0030] As the Portland cement clinker, the Portland cement clinker used for preparing various Portland cements specified in JIS R 5210:2003 "Portland Cement" can be used. Examples of the various Portland cements include ordinary Portland cement, early-strength Portland cement, super-early-strength Portland cement, medium-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, etc. The Portland cement clinker may be the Portland cement clinker used for preparing ordinary Portland cement and early-strength Portland cement.

[0031] The mineral composition of Portland cement clinker can be calculated by the Bogue formula. Here, the Bogue formula is a formula widely used to calculate the content ratio of the main minerals in Portland cement clinker from the content ratio of the chemical composition. By using the Bogue formula shown below, the content of tricalcium silicate (3CaO·SiO 2、 represented by C3S), dicalcium silicate (2CaO·SiO 2、 represented by C2S), and tricalcium aluminate (3CaO·Al2O 3、 represented by C3A) in Portland cement clinker can be calculated. In the following formula, "%" means "mass%". The chemical formula represents the content ratio (mass%) of each compound shown by the chemical analysis value according to JIS R 5204:2019 "Fluorescent X-ray Analysis Method for Cement".

[0032] <Bogue formula> C3S[%]=(4.07×CaO[%])-(7.60×SiO2[%])-(6.72×Al2O3[%])-(1.43×Fe2O3[%])-(2.85×SO3[%]) C2S[%]=(2.87×SiO2[%])-(0.754×C3S[%]) C3A[%]=(2.65×Al2O3[%])-(1.69×Fe2O3[%]) C4AF[%]=3.04×Fe2O3[%]

[0033] Examples of alkali carbonates include sodium carbonate decahydrate (Na2CO3·10H2O), sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and sodium sesquicarbonate dihydrate (Na3H(CO3)2·NaHCO3·2H2O). These alkali carbonates may be used alone or in combination of two or more.

[0034] The content of the alkaline activator in the hydraulic composition may be, for example, 10 to 90% by mass based on the total amount of the hydraulic composition. From the viewpoint of sufficiently increasing the compressive strength of the hardened body, the lower limit of the content may be 20%, 30%, 40%, 50%, or 60% by mass. From the viewpoint of effectively utilizing volcanic ejecta deposits, the upper limit of the content may be 80%, 70%, or 60% by mass.

[0035] From the viewpoint of sufficiently increasing the compressive strength of the hardened body, the total content of the volcanic ejecta deposits and alkaline activator in the hydraulic composition may be 60 mass% or more, 70 mass% or more, 90 mass% or more, or even 100 mass% (consisting essentially of volcanic ejecta deposits and alkaline activator) based on the total amount of the hydraulic composition.

[0036] The allophane content in the hydraulic composition may be 3 to 30 mass%, 5 to 25 mass%, or 6 to 15 mass%, based on the total amount of the hydraulic composition, from the viewpoint of sufficiently increasing the compressive strength of the hardened body. The allophane content in the volcanic ejecta deposits may be 20 mass% or more, 35 mass% or more, 50 mass% or more, or 65 mass% or more, from the viewpoint of sufficiently increasing the compressive strength of the hardened body. The allophane content in the volcanic ejecta deposits may be 90 mass% or less, or 80 mass% or less, from the viewpoints of easy availability and reduced production costs.

[0037] The hydraulic composition may contain other components in addition to the volcanic ejecta deposits and the alkaline activator. Examples of the other components include inorganic fine powder, gypsum, carbonates, etc. The content of the other components may be 40% by mass or less, 20% by mass or less, or 15% by mass or less based on the total amount of the hydraulic composition.

[0038] The hydraulic composition may contain a carbonate. The carbonate promotes the hydration reaction between the alkaline activator and volcanic glass contained in volcanic deposits. The carbonate may be a carbonate other than an alkali metal salt, such as an alkaline earth metal carbonate or a hydrate thereof, such as calcium carbonate (limestone) or magnesium carbonate. Examples of limestone include commonly available limestone powder and powders containing calcium carbonate as the main component, such as kansui stone powder. The limestone preferably includes one that complies with the minor mixing components described in JIS R 5210:2009 "Portland Cement."

[0039] From the viewpoint of fluidity, the content of carbonate in the hydraulic composition may be 20 mass % or less based on the total amount of the hydraulic composition.

[0040] The use of inorganic fine powder can further increase the compressive strength of the hardened body. Examples of inorganic fine powder include powdered materials such as silica stone and crushed stone. The content of the inorganic fine powder in the hydraulic composition may be more than 0 mass % and 15 mass % or less based on the total amount of the hydraulic composition, from the viewpoint of achieving both high levels of fluidity and compressive strength.

[0041] Gypsum has the function of adjusting the hydration reaction rate in the hydraulic composition. Examples of gypsum include gypsum dihydrate, gypsum hemihydrate, and anhydrous gypsum. The content of gypsum in the hydraulic composition may be more than 0 mass% and 5 mass% or less based on the total amount of the hydraulic composition.

[0042] The allophane content in a hydraulic composition affects the compressive strength of a set body. In the manufacturing method for a hydraulic composition of this embodiment, in the blending step, the blending ratio of the above-mentioned raw materials is adjusted based on the estimated value of the allophane content derived by the above-mentioned estimation method. This suppresses the variation in the allophane content in the hydraulic composition, and makes it possible to rapidly manufacture a hydraulic composition capable of forming a set body with little variation in performance. In the blending step, the volcanic ejecta deposit, the alkaline activator, and the other optional components described above are mixed. The other components described above may be mixed together when the volcanic ejecta deposit and the alkaline activator are mixed. The raw materials may be blended in a ratio that results in the content in the hydraulic composition described above.

[0043] In the blending step, each raw material may be pulverized. When pulverization is performed, the order of mixing and pulverization is not particularly limited. That is, each raw material may be mixed and then pulverized, each raw material may be pulverized individually and then mixed, or each raw material may be mixed and pulverized simultaneously. Mixing may be performed using a mixer such as a pan mixer, a tilting mixer, or a ribbon mixer. Alternatively, mixing and pulverization may be performed using a pulverizer such as a ball mill, a vertical roller mill, or a roller press. Furthermore, each raw material may be pulverized individually and then mixed using a mixer such as a mechanical mixer. In this way, a hydraulic composition in which the allophane content can be rapidly adjusted can be produced.

[0044] The method may include a step of calcining the volcanic deposits prior to the blending step. The calcination temperature may be 500°C or higher from the viewpoint of increasing compressive strength. Furthermore, the calcination temperature may be 950°C or lower from the viewpoint of suppressing the use of tetrahedral Al and pentahedral Al in the formation of other minerals (e.g., mullite). From these viewpoints, the calcination temperature may be 600 to 900°C. The calcination time is not particularly limited, and may be 0.5 to 5 hours or 1 to 4 hours from the viewpoint of the effect on the crystal structure. By including the calcination step, a hardened body having even higher compressive strength can be obtained.

[0045] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The present disclosure includes the following embodiments [1] to [9].

[0046] [1] A method for estimating the allophane content contained in volcanic ejecta deposits, comprising: The SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, and Fe 3+ and Fe 2+ Fe relative to the total amount of 3+the allophane content in the volcanic ejecta deposit is estimated using at least one measured value selected from the group consisting of an ion ratio of [2] SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe of volcanic deposits used to create the regression equation 3+ and Fe 2+ Fe relative to the total amount of 3+ a regression equation creation step of creating a regression equation using at least one measured value selected from the group consisting of the ion ratio of the volcanic ash, the a value in the Lab color system, and the b value in the Lab color system as an explanatory variable, and a measured value of the allophane content in the volcanic ejecta deposit used to create the regression equation as a response variable, The estimation method according to [1], wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation. [3] In the regression equation creation step, the SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe of the volcanic ejecta deposits used to create the regression equation are calculated. 3+ and Fe 2+ Fe relative to the total amount of 3+ a multiple regression equation is created using at least two measured values ​​selected from the group consisting of the ion ratio of the above-mentioned ion ratio, the a value in the Lab color system, and the b value in the Lab color system as explanatory variables, and the measured value of the allophane content in the volcanic ejecta deposit used to create the regression equation as a response variable, The estimation method according to [2], wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the multiple regression equation. [4] The estimation method according to [2] or [3], wherein the volcanic ejecta deposit used to create the regression equation has an SiO2 content of 30 to 80 mass%, an Al2O3 content of 5 to 45 mass%, and an R2O content of 0.1 to 10 mass%. [5] The a value of the volcanic ejecta deposits used to create the regression equation is 0.1 to 10, and the b value is 1 to 20; In the regression equation creation step, the regression equation is created using at least one or both of the measured values ​​of the a value and the b value as explanatory variables; The estimation method according to any one of [2] to [4], wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation. [6] The integrated value of the heat of hydration of the volcanic ejecta deposits used to create the regression equation is 0 to 50 J / g; In the regression equation creation step, the regression equation is created using at least the measured values ​​of the heat of hydration as explanatory variables; The estimation method according to any one of [2] to [5], wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation. [7] The BET specific surface area of ​​the volcanic deposits used to create the regression equation is 5 to 500 m 2 / g, In the regression equation creation step, the regression equation is created using at least the measured value of the BET specific surface area as an explanatory variable; The estimation method according to any one of [2] to [6], wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation. [8] A method for producing a hydraulic composition, comprising a blending step of blending at least volcanic ejecta deposits and an alkaline activator as raw materials, A method for producing a hydraulic composition, wherein in the mixing step, the mixing ratio of the raw materials is adjusted based on the estimated value of the allophane content contained in the volcanic ejecta deposit derived by the estimation method according to any one of [1] to [7]. [9] The method for producing a hydraulic composition according to [8], further comprising a pretreatment step of calcining the volcanic ejecta deposits prior to the mixing step. [Example]

[0047] The present disclosure will be described in more detail below with reference to specific examples, although the present disclosure is not limited to the following examples.

[0048] Example 1 [Estimation of allophane content] As sediment of volcanic ejecta (hereinafter referred to as "sediment"), as shown in Table 1, Secard P-1 (manufactured by Shinagawa General Co., Ltd., trade name), Kanuma soil (manufactured by Akagi Horticulture Co., Ltd.), Satsuma soil (manufactured by Yamichi Pumice Co., Ltd.), VGP-1 (manufactured by Principle Co., Ltd., trade name), and black peat soil (commercially available product) were prepared.

[0049] <Measurement of chemical components> Fluorescent X-ray analysis (XRF) of the above sediment was performed to measure the contents of Si, Al, Na, and K. These were converted into oxides respectively to obtain the SiO2 content, Al2O3 content, Na2O content, and K2O content. The R2O content was calculated as Na2O content + 0.658K2O content. The results are shown in Table 1.

[0050] <Measurement of hydration heat generation> The hydration heat generation of the above sediment was measured. Each sediment and water were mixed at a mass ratio of 1:1 to prepare a measurement sample. Using a conduction calorimeter (manufactured by TA Instruments, device name: TAM Air), the hydration heat generation of each measurement sample was measured. The integrated values of the hydration heat generation rate and the hydration heat generation amount were as shown in Figures 1(A) and (B). The integrated heat generation amount for 1 hour is shown in Table 1. The numbers in Figures 1(A) and (B) are the same as those shown in Table 1.

[0051] <Measurement of BET specific surface area> Each sediment was heated at 105 °C for 1 hour in a nitrogen gas atmosphere for drying. For each sediment after heating, the adsorption amount of nitrogen gas was measured using BELSORP MINI manufactured by MicrotracBEL. The specific surface area was calculated based on the measurement results. The results are shown in Table 1.

[0052] <Measurement of color> The color of each sediment was measured three times for the L value, a value, and b value using a spectrocolorimeter (manufactured by Nippon Denshoku Industries Co., Ltd., SE7700) by the method of Hunter 1948, and the average value was obtained. The results are shown in Table 2.

[0053] <Fe 2+ and Fe3+ Measurement of content> In accordance with JIS K 0102:2016 "Testing Methods for Industrial Wastewater," Fe in each sediment was measured using an ultraviolet-visible spectrophotometer (U-2900 model: Hitachi High-Tech Science Corporation). 2+ and Fe 3+ The results are shown in Table 2. In Table 2, T-Fe represents Fe 2+ and Fe 3+ means the total amount of Fe 2+ , Fe 3+ and T-Fe contents are the ratios of the number of these cations to the total cations in each sediment (cation %).

[0054] [Table 1]

[0055] [Table 2]

[0056] <Measurement of allophane content (actual measurement)> The allophane content of each sediment was measured by the acid-alkali alternating dissolution method. Specifically, the measurement was performed according to the following procedure.

[0057] First, organic matter was removed from the volcanic ejecta deposits using the following method. Specifically, the sample was first sieved through a 0.425 mm sieve. 50 ml of 10% by mass hydrogen peroxide solution was added to the sample that passed through the sieve, and the mixture was heated in a water bath. Next, 20 ml of 30% by mass hydrogen peroxide solution was added, and the mixture was heated in a water bath for 24 hours. After that, a sufficient amount of distilled water was added to the sample, and the aqueous phase was separated by centrifugation (2800 rpm, 6 minutes) to wash the sample. The washing was performed twice. The washed sample was then dried at 105°C for 24 hours.

[0058] The dried sample was subjected to the following series of steps (1) to (7) five times. (1) 50 ml of 8 M hydrochloric acid was added to the sample (volcanic deposit) and shaken for 30 minutes. (2) A sufficient amount of distilled water was added to the sample, and the sample was washed by separating the aqueous phase by centrifugation (2800 rpm, 6 minutes). (3) 50 ml of 0.5 M aqueous sodium hydroxide solution was added to the washed sample, and the sample was heated in a water bath at 60°C for 5 minutes. (4) The aqueous phase was separated by centrifugation (2800 rpm, 6 minutes) and the sample was washed. (5) A sufficient amount of distilled water was added to the sample, and the sample was washed by separating the aqueous phase by centrifugation (2800 rpm, 6 minutes). (6) After washing, the sample was dried at 105°C for 24 hours. (7) After drying, the weight of the sample was measured. By repeating the series of steps (1) to (7) five times, it was confirmed that the weight change of the sample due to leaching had almost completely disappeared. The allophane content was calculated based on the weight loss rate. The results are shown in Table 3.

[0059] [Table 3]

[0060] <Single correlation> The correlation (simple correlation) between the allophane content (measured value) in Table 3 and each measurement value shown in Tables 1 and 2 was investigated. The results are shown in Figures 2 and 3. The coefficient of determination for each correlation, R 2 The regression equations are shown in the graphs of each figure. In the regression equations, x is the allophane content (mass%), and y is each measured value shown in Tables 1 and 2. For measured values ​​related to iron ions, Fe 3+ / Fe 2+ and Fe 3+ / T-Fe showed a high correlation with the allophane content.

[0061] <Multiple correlation> The ten measured values ​​in Tables 1 and 2 (SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, Fe 3+ and Fe 2+ Fe relative to the total amount of3+ Two measured values ​​selected from the group consisting of the ion ratio of 100% and 110% of the total, the a value in the Lab color system, and the b value in the Lab color system were used as explanatory variables (X value 1, X value 2), and the allophane content (actual measured value) in Table 3 was used as the objective variable (Y value). The coefficients that minimized the sum of squares of the residuals using the least squares method were determined, and based on these results, the multiple regression equation represented by the following equation (I) was derived. This derivation was performed for any combination of two property values. The coefficients α, β, and intercept γ of the derived multiple regression equation, as well as the correlation coefficient, are shown in Table 4. Y=αX1+βX2+γ (I)

[0062] [Table 4]

[0063] The correlation between the allophane content (measured value) shown in Table 3 and the allophane content (estimated value) estimated from each multiple regression equation shown in Table 4 was examined. Figures 4 to 8 show graphs in which the horizontal axis represents the measured allophane content and the vertical axis represents the estimated allophane content derived from each multiple regression equation. In Figures 4 to 8, (%) represents (mass %). Table 4 lists the figure numbers corresponding to each multiple regression equation. The coefficient of determination R for each correlation is shown on each graph. 2 The regression equations are shown in Table 4. In the regression equations, x is the measured value of allophane content (mass%), and y is the estimated value of allophane content (mass%). Table 4 also shows the coefficient of determination R 2 is shown to three decimal places.

[0064] As shown in the graphs of Figures 4 to 8, it was confirmed that there was a sufficiently high correlation between all of them. From these results, it was found that the SiO2 content, Al2O3 content, Na2O content, K2O content, R2O content, calorific value of hydration, BET specific surface area, and Fe 3+ and Fe 2+ Fe relative to the total amount of 3+ It was confirmed that the allophane content can be estimated with sufficiently high accuracy based on two measured values ​​selected from the group consisting of the ion ratio of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 39, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 59, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73

[0065] Example 2 [Production and evaluation of hydraulic compositions] <Preparing raw materials> The five types of deposits shown in Table 2 used in Example 1 were calcined in air at 900°C for 3 hours in a calcination furnace (pretreatment). Separately, commercially available ordinary Portland cement (manufactured by UBE Mitsubishi Cement Corporation) was prepared as an alkali activator. Limestone (325 mesh fine limestone powder, manufactured by Ube Material Industries, Ltd.) was also prepared.

[0066] <Production of hydraulic composition> Next, hydraulic compositions were prepared by mixing the calcined sediment and / or limestone prepared as described above with an alkaline activator according to the formulation shown in Table 5. Table 5 shows the allophane content in the hydraulic composition calculated from the blending ratio of the sediment and the actual value of the allophane content shown in Table 3.

[0067] [Table 5]

[0068] <Preparation of hardened body> The prepared hydraulic composition was mixed with water and standard sand for cement strength testing provided by the Japan Cement Association as fine aggregate, and a hardened body was prepared in accordance with the method described in JIS R 5201:2015 "Physical Testing Methods for Cement." The prepared hardened body was cured underwater in a thermostatic chamber at 20°C for ages of 7 and 28 days.

[0069] <Compression strength measurement> The compressive strength of each hardened body was measured at ages of 7 days and 28 days. The compressive strength was measured in accordance with the method described in JIS R 5201:2015 "Physical Testing Methods for Cement." Table 6 shows the strength ratio (%) of the hardened body calculated from the measured compressive strength. This strength ratio (%) (1) / (2) is the ratio of the compressive strength (1) at each age of the hardened body produced using raw materials containing the calcined deposit to the compressive strength (2) at each age of the hardened body produced using only the alkaline activator used in the production of the hydraulic composition.

[0070] [Table 6]

[0071] The column for strength ratio (%) (standard: limestone) in Table 6 shows the ratio of the compressive strength (1) of the hardened bodies (Nos. 5, 15, and 24) when only limestone is used instead of volcanic deposits as the mineral to the standard (100) of the compressive strength (1) of the hardened bodies when part or all of the limestone is replaced with calcined deposits.

[0072] 9(A), (B), and (C) are graphs in which data for each sample is plotted, with the horizontal axis representing the allophane content of the hydraulic composition shown in Table 5 and the vertical axis representing the "strength ratio (%)(1) / (2)" from Table 6. FIG. 9(A) shows data for a sample containing 10% by mass of volcanic ejecta deposits or limestone. FIG. 9(B) shows data for a sample containing 30% by mass of volcanic ejecta deposits or limestone. FIG. 9(C) shows data for a sample containing 50% by mass of volcanic ejecta deposits or limestone. In each of the graphs in FIGS. 9(A), (B), and (C), the open plots represent data at a 7-day age, and the solid plots represent data at a 28-day age.

[0073] As shown in Figures 9(A), (B), and (C), the strength ratio tended to increase with increasing allophane content. Many of the hardened specimens had compressive strengths equivalent to those produced using only alkaline activators.

[0074] 10(A), (B), and (C) are graphs in which data for each sample is plotted, with the horizontal axis representing the allophane content of the hydraulic composition shown in Table 5 and the vertical axis representing the "strength ratio (%) (standard: limestone)" from Table 6. FIG. 10(A) shows data for a sample containing 10% by mass of volcanic ejecta deposits or limestone. FIG. 10(B) shows data for a sample containing 30% by mass of volcanic ejecta deposits or limestone. FIG. 10(C) shows data for a sample containing 50% by mass of volcanic ejecta deposits or limestone. In each of the graphs in FIGS. 10(A), (B), and (C), the open plots represent data for a sample aged 7 days, and the solid plots represent data for a sample aged 28 days.

[0075] As shown in Figures 10(A), (B), and (C), the strength ratio tends to increase as the allophane content increases. It was also confirmed that hardened specimens made from volcanic ejecta deposits containing allophane have compressive strengths equal to or greater than those made from limestone.

Claims

1. A method for estimating the allophane content contained in a volcanic ejecta deposit, comprising: SiO of the volcanic deposits ２ Content, Al ２ O ３ Content, Na ２ O content, K ２ O content, R ２ O content, hydration calorific value, BET specific surface area, Fe ３＋ and Fe ２＋ Fe relative to the total amount of ３＋ the ion ratio of 1 to 2, the a value in the Lab color system, and the b value in the Lab color system, and estimating the allophane content contained in the volcanic ejecta deposit.

2. SiO of volcanic deposits for creating regression equations ２ Content, Al ２ O ３ Content, Na ２ O content, K ２ O content, R ２ O content, hydration calorific value, BET specific surface area, Fe ３＋ and Fe ２＋ Fe relative to the total amount of ３＋ a regression equation creation step of creating a regression equation using at least one measured value selected from the group consisting of the ion ratio of The estimation method according to claim 1 , wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation.

3. In the regression equation creation step, SiO of the volcanic ejecta deposits used to create the regression equation is ２ Content, Al ２ O ３ Content, Na ２ O content, K ２ O content, R ２ O content, hydration calorific value, BET specific surface area, Fe ３＋ and Fe ２＋ Fe relative to the total amount of ３＋ a multiple regression equation is created using at least two measured values ​​selected from the group consisting of the ion ratio of the volcanic ash, the a value in the Lab color system, and the b value in the Lab color system as explanatory variables, and the measured value of the allophane content in the volcanic ejecta deposit used to create the regression equation as a response variable, The estimation method according to claim 2 , wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the multiple regression equation.

4. SiO of the volcanic ejecta deposits used to create the regression equation ２ Content is 30-80% by mass, Al ２ O ３ The content is 5 to 45 mass%, R ２ The estimation method according to claim 2 or 3, wherein the O content is 0.1 to 10 mass%.

5. the a value of the volcanic ejecta deposits used to create the regression equation is 0.1 to 10 and the b value is 1 to 20; In the regression equation creation step, the regression equation is created using at least one or both of the measured values ​​of the a value and the b value as explanatory variables; The estimation method according to claim 2 or 3, wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation.

6. the integrated value of the heat of hydration of the volcanic ejecta deposit for creating the regression equation is 0 to 50 J / g; In the regression equation creation step, the regression equation is created using at least the measured values ​​of the heat of hydration as explanatory variables; The estimation method according to claim 2 or 3, wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation.

7. The BET specific surface area of ​​the volcanic ejecta deposits used to create the regression equation is 5 to 500 m ２ / g, In the regression equation creation step, the regression equation is created using at least the measured value of the BET specific surface area as an explanatory variable; The estimation method according to claim 2 or 3, wherein the estimation step estimates the allophane content of the volcanic ejecta deposit using the regression equation.

8. A method for producing a hydraulic composition, comprising a blending step of blending at least volcanic ejecta deposits and an alkaline activator as raw materials, A method for producing a hydraulic composition, wherein in the blending step, a blending ratio of the raw materials is adjusted based on an estimated value of the allophane content contained in the volcanic ejecta deposit derived by the estimation method according to any one of claims 1 to 3.

9. The method for producing a hydraulic composition according to claim 8, further comprising a pretreatment step of calcining the volcanic ejecta deposit before the mixing step.

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