JP6350985B2 - Hardener for ground stabilization chemical and ground stabilization chemical - Google Patents

Description

  The present invention relates to a ground stabilization chemical solution mainly composed of an alkali silicate aqueous solution and a curing agent used for the ground stabilization chemical solution for ground stabilization.

2. Description of the Related Art Conventionally, a ground stabilization method is known in which various ground stabilization chemicals are injected into the ground and gelled in the ground in order to strengthen the soft ground or stop the water leakage ground.
As a chemical solution, since it is inexpensive, an alkali silicate-based ground stabilization chemical solution, which is a chemical solution in which an aqueous solution of an alkali silicate is used as a main ingredient and an aqueous solution of a curing agent component or a suspension solution dispersed in water, is widely used. Yes.

Examples of curing agents used in alkali silicate ground stabilization chemicals include curing agents that combine gypsum such as dihydrate gypsum, hemihydrate gypsum, and type II anhydrous gypsum with lime such as slaked lime and quicklime. It has been.
Among these, the present applicant, as an inventor, in Patent Document 1, a combination of lime and gypsum as a curing agent, and in Patent Document 2, a surfactant is combined with lime and gypsum as a curing agent. A hardener was proposed. In Patent Document 3, as in Patent Document 2, a combination of a surfactant and a lime and gypsum as a curing agent is proposed.
The limes in the curing agents of Patent Document 1 and Patent Document 2 use slaked lime and / or quick lime, and the gypsum is selected from the group consisting of dihydrate gypsum, α hemihydrate gypsum, β hemihydrate gypsum, and type II anhydrous gypsum. In addition, the amount ratio of limes: gypsum is a mixing ratio of 1: 3 to 3: 1 (mass ratio). The surfactant of Patent Document 2 is a nonionic or anionic surfactant. Patent Document 3 proposes, as in Patent Document 2, a curing agent in which a surfactant is combined with lime and gypsum as a curing agent, lime is slaked lime, gypsum is type II anhydrous gypsum, and surfactant. Is an anionic surfactant lignin sulfonate. Ground stabilization chemicals that use this hardener have a high initial strength when applied by the instantaneous setting method that hardens in the ground within a few seconds to a few tens of seconds. Produces the effect that it is difficult to homogenize.

Patent Document 1, Patent Document 2, and Patent Document 3 describe the particle size of the curing agent, the amount of the curing agent used, and the amount of nonionic surfactant or anionic surfactant used as follows. .
-Although the particle size of a hardening | curing agent does not have a description matter in patent document 1, in patent document 2, it is preferable to use what was grind | pulverized in the range of 3000-9000 cm < ² > / g by the specific surface area by a brane method. In Patent Document 3, slaked lime has a maximum particle size of 600 μm or less, preferably 150 μm or less, and 10 μm or more. It is described that type II anhydrous gypsum has a maximum particle size of 90 μm or less, preferably 5 μm or more.
-Use a large amount of curing agent when shortening the curing time of chemicals, and use a small amount when increasing the curing time. For example, in the case where the ground is stabilized by a chemical solution 400 l composed of a mixture of JIS No. 3 sodium silicate 100 l and water 100 l and a main component liquid 200 l and an equal volume of the curing agent liquid 200 l, a curing agent is added to the curing agent liquid. When it is contained in the range of 40 to 180 kg, the chemical solution is cured in several seconds to tens of seconds. In other words, in order to cure a chemical liquid 400 l composed of a mixture of a main agent liquid 200 l composed of JIS No. 3 sodium silicate 100 l and water 100 l and an equal volume of a curing agent liquid 200 l, in Patent Document 1, the curing agent is 40 In the range of ~ 180 kg, at least 40 kg is required, the curing agent of Patent Document 2 is in the range of 60-180 kg, and at least 60 kg is required, in Patent Document 3, the range of 40-80 kg within the range of Patent Document 1 It is stated that 55 kg is necessary.
-The amount of nonionic or anionic surfactant used is not described in Patent Document 1, but in Patent Document 2, it is usually contained in the range of 0.4 to 1.5 kg per 200 l of the curing agent liquid. Patent Document 3 discloses that an anionic surfactant lignin sulfonate is in the range of 0.058 to 0.48 kg when the curing agent amount is 55 kg per 200 l of the curing agent liquid. It is described in Table 2 that the curing time does not cure within a few seconds, but the curing agent liquid can be homogenized.

Japanese Examined Patent Publication No. 62-9154 Japanese Examined Patent Publication No. 62-9155 JP 2009-203316 A

Conventionally, as a chemical solution for stabilizing the ground, a multipurpose and versatile curing agent has been desired so that it can be used at a low price and excellent in performance, in particular, a diversified and complicated ground.
Therefore, it is cheaper than the curing agents described in Patent Documents 1, 2, and 3, is environmentally friendly, and can effectively utilize industrial by-products, and can stabilize and stabilize more stable and diversified ground. Therefore, there has been a demand for a curing agent for stabilizing the ground that can be used in various ways for various purposes.
The object of the present invention is to support diversified and complicated ground stabilization without using the expensive type II anhydrous gypsum described in the above three patent documents when mixed with an alkali silicate aqueous solution. Inexpensive, environmentally friendly, effective use of industrial by-products for which resource saving is desired, and by arbitrarily adjusting the amount of curing agent, curing time can be set from long to short, and high compression strength An object of the present invention is to provide a curing agent for ground stabilization chemical solution and a ground stabilization chemical solution that can be obtained from strength to practical strength and can be used for various purposes and versatile purposes.

In order to solve the above-mentioned problems, the present inventor, as the properties of the anhydrous gypsum composition, the properties of a paper packaging bag, the properties of a SPCC (cold rolled steel plate) test piece, the pH of the preparation tank, the curing agent liquid (B liquid) defoaming property, viscosity,
It was decided that the curing time (gel time), the strength of the cured body (homogel body), etc. satisfied all the following criteria simultaneously.
(1) Properties of paper packaging bag Add alkaline substance to hydrofluoric acid by-product gypsum and hydrofluoric acid by-product gypsum into inexpensive paper kraft paper bag, and (1) mixing (hereinafter referred to as mixing process) (2) ▼ Anhydrous gypsum composition obtained by processing by three types of preparation methods: pulverization / classification (hereinafter referred to as pulverization / classification process), ③ mixing, pulverization / classification (hereinafter referred to as mixing, pulverization / classification process) And left at room temperature. Kraft paper bags should not be broken for 12 months.
(2) pH of the mixing tank
Hardener liquid (liquid B)
By adjusting the pH of the mixture to 4.5 or more, corrosion in the preparation tank is not recognized for one day. As a result, the anhydrous gypsum composition of the present invention is a manufacturing facility such as piping for hydrofluoric acid by-product gypsum discharged from a rotary kiln, a transport device, a mixing device, a pulverizer, a classification device, a curing agent liquid preparation device, an injection device, and an injection device. The injection equipment such as the pipe and the injection pipe tip equipment can be made of inexpensive materials, so that the economic efficiency is improved, and at the same time, the pH of the anhydrous gypsum composition enters from the neutral region to the alkaline region. Effective and efficient use and reuse of good and environmentally friendly industrial by-products, and eco-products that meet social needs.
(3) Properties of SPCC test piece 200cc Tap water 190cc into the mixing tank, hydrofluoric acid byproduct gypsum alone, alkaline substance added to hydrofluoric acid byproduct gypsum (1) mixing process, (2) grinding and classification process, ▲ 3 ▼ 30g of anhydrous gypsum composition obtained by the three preparation methods of mixing, crushing and classification processes, mixing and stirring, followed by SPCC (cold rolled steel plate) 50 x 30 x 2 mm test The piece was immersed and left for 1 day, and the corrosion state of the test piece was observed.
SPCC test pieces immersed in the mixing tank should not corrode even if left for 1 day.
(4) Antifoaming property of curing agent liquid Curing agent 10-80 g, surfactant 0-1.0 g, antifoaming agent 0-2.0 g, curing acceleration enhancer 15-80 g dissolved in water and suspended. The foam disappeared within 10 seconds after stirring of 200 cc of the resulting curing agent liquid (B liquid) was stopped.
(5) Viscosity of hardener liquid 200 cc of hardener liquid (liquid B) is dispensed into a graduated cylinder and charged into a measuring container and kept in a constant temperature water bath kept at 20 ° C. until reaching a certain temperature. Next, when the liquid temperature reached a certain temperature, the viscosity of the solution was measured with a B-type viscometer.
(6) Curing time of chemical solution and uniaxial compressive strength of the cured body Using No. 3 sodium silicate as defined in Japanese Industrial Standard (JIS K-1408) as alkali silicate, prepared by mixing 100 cc of No. 3 sodium silicate and 100 cc of water Prepared by dissolving and suspending 200 cc of the main agent liquid (A liquid), 10-80 g of the curing agent, 0-1.0 g of the surfactant, 0-2.0 g of the antifoaming agent, and 15-80 g of the curing acceleration enhancing agent in water. The chemical solution obtained by mixing equal volumes of the curing agent solution (B solution) obtained in this manner was as follows at a temperature of 20 ° C.
The curing time should be cured (gelation) from the long 20 minutes range to a few seconds of instantaneous setting.
The cured body strength is that the uniaxial compressive strength value of the formed cured body is 0.01 N / mm ² or more after one day has elapsed after the chemical solution is cured.
As a result of examining a curing agent that satisfies all of the above criteria, the present inventor,
(A) An anhydrous gypsum composition composed of hydrofluoric acid byproduct gypsum, which is a component of the curing agent, appropriately performs a solid-phase reaction between free sulfuric acid contained in the hydrofluoric acid byproduct gypsum and an alkaline substance, Provide a mixing process and pulverization / classification process to ensure the neutralization reaction.
(B) The fineness of the anhydrous gypsum composition of the above (a) should be specified by the specific surface area by the Blaine method.
(C) An anhydrous gypsum composition, a surfactant, an antifoaming agent, and a curing acceleration enhancer composed of hydrofluoric acid byproduct gypsum, which is a constituent of a curing agent, and an alkaline substance, are used in a specific range. We found that all the criteria were met.
And the knowledge came to invent the following hardening agents for ground stabilization chemical | medical solutions, and ground stabilization chemical | medical solutions.

That is, this invention includes the following aspects.
(1) and A solution consisting of alkali silicate aqueous solution, by the hydrofluoric acid byproduct gypsum ((a) component) and hydrofluoric acid byproduct gypsum 100 parts by weight, the amount to neutralize the free sulfuric acid contained in the hydrofluoric acid byproduct gypsum The specific surface area according to the Blaine method obtained by adding one or two or more alkaline substances (component (b)) to 500 parts by mass or more, and mixing, pulverizing and classifying them is 4500 to 15000 cm ² / g. The amount of the surfactant (component (c)) is 0.35 or more and 1.25 parts by mass or less with respect to 100 parts by mass of the anhydrous gypsum composition and 100 parts by mass of the anhydrous gypsum composition and the hardening accelerator. (C) The content of the antifoaming agent (component (d)) is 0.51 or more and 200 parts by weight or less with respect to 100 parts by weight of the component, and a curing acceleration enhancer (component (e)) is added if necessary. The aqueous slurry B, which is dispersed in water, is injected into the ground, and the ground A curing agent for ground stabilization chemicals, characterized in that it is cured inside to stabilize the ground.
(2) The alkaline substance is a compound comprising oxides such as calcium, magnesium, potassium, sodium, hydroxides, carbonates, bicarbonates, etc., or a double salt or cement comprising these compounds. Hardener for ground stabilization chemicals.
(3) A ground stabilization chemical containing the curing agent for ground stabilization chemical according to (1) or (2) and an aqueous alkali silicate solution.

The hardener for ground stabilization chemical solution of the present invention can be obtained by using inexpensive industrial by-product hydrofluoric acid byproduct gypsum without using expensive type II anhydrous gypsum when mixed with alkaline silicate aqueous solution. It has excellent permeability to water, and by adjusting the amount of anhydrous gypsum composition and curing accelerator, the curing time can be adjusted from 20 minutes for long set to several seconds for quick setting. Can be obtained from a practical strength of 0.01 N / mm ² to a high strength of 6 N / mm ² . Because of this, diversified and complicated ground can be stabilized more reliably and safely, and can be applied to multipurpose and versatile applications.

[Curing agent for ground stabilization chemicals]
The curing agent used in the soil stabilization chemical solution of the present invention is a curing agent used in a soil stabilization chemical solution mainly composed of an aqueous alkali silicate solution, and contains an alkaline substance ((b) component in hydrofluoric acid byproduct gypsum (component (a)). ), Mixed, pulverized and classified, an anhydrous gypsum composition, and a surfactant (component (c)) and an antifoaming agent (component (d)) for the anhydrous gypsum composition And, if necessary, a curing acceleration enhancer (component (e)).

[Hydrofluoric acid by-product anhydrous gypsum]
The hydrofluoric acid byproduct gypsum is used as a main raw material when preparing the anhydrous gypsum composition used as the curing agent of the present invention.
Usually, hydrofluoric acid byproduct gypsum produces hydrofluoric acid and gypsum (hereinafter referred to as hydrofluoric acid byproduct gypsum) from the rotary kiln outlet when hydrofluoric acid is produced by decomposing fluorite with sulfuric acid at high temperature.
The hydrofluoric acid byproduct gypsum usually contains 0.2 to 5% by weight (as sulfuric acid) of free acid. Therefore, the acidity is strong, and the pH is strong acidity around 1.0. In addition to the free acid, water-soluble hydrofluoric acid, iron, and the like are also included, so there is no use as it is, and it is used as an additive for cement after forced hydration.
As the hydrofluoric acid byproduct gypsum used in the present invention, those produced from a rotary kiln are usually used. The particle size of the hydrofluoric acid byproduct gypsum from the rotary kiln is in a wide range from bulk to powder. Therefore, the raw material for the curing agent used in the present invention has a number of problems in the bulk to powder particle size as it is, and it is difficult to provide practicality.
Calcium fluoride used in the present invention is a naturally occurring meteorite represented by the composition formula CaF ₂ , and is obtained by recovery or synthesis, which is mainly used in industry and is mainly composed of calcium fluoride. , it is possible to use those that contain components other than CaF _2. The main component of calcium fluoride is preferably 90% or more and 95% or more.
As the hydrofluoric acid byproduct gypsum used in the present invention, those produced by reacting the calcium fluoride with sulfuric acid can be used.

[Alkaline substances]
The alkaline substance used in the present invention has a strong acidity with a hydrofluoric acid byproduct gypsum used in the present invention having a pH of around 1, which improves handling safety, handling workability, working environment, etc., and prevents corrosion related to transportation equipment. , Reduction of related equipment investment, preparation of product packaging so that it can be applied to cheap kraft bags, and use of iron in the water, injection pipe, injection pump, instrumentation It is added to prevent injection-related equipment such as related equipment from corroding, and to adjust the curing time and increase the strength of the cured body.
The alkaline substance used in the present invention is used to neutralize hydrofluoric acid anhydrous gypsum, which is the main raw material of the anhydrous gypsum composition, because it contains a large amount of free sulfuric acid.
Examples of the alkaline substance used in the present invention include calcium, magnesium, potassium, sodium oxides, hydroxides, carbonates, bicarbonates, and the like, and double salts or cements of the compounds. One or a mixture of two or more can be used.
Of these alkaline substances, water-insoluble calcium oxide, calcium hydroxide, calcium carbonate, dolomite, cement, and the like can be suitably used because they can be applied to various construction situations. Water-soluble alkaline substances such as sodium hydroxide, potassium hydroxide, sodium oxide, potassium oxide, etc. are wasted even if a larger amount than neutralizing the free sulfuric acid contained in hydrofluoric acid anhydrous gypsum is wasted. Even if it exists, it is preferable to keep about 2-3 times the neutralization amount. Use of more than this is extremely effective for stabilizing paper bags of products, and preventing corrosion of metals such as manufacturing equipment, transport equipment, injection equipment, etc., but it is not preferable because it causes a delay in curing time and a decrease in strength. is there.
Alkaline substances used in the present invention are calcium, magnesium, potassium, sodium oxides, hydroxides, carbonates, bicarbonates, etc., and double salts, cements, etc. of these compounds are all commercially available for industrial use. Goods can be used.
Examples of the cement include Portland cement, mixed cement, and ecocement. Examples of Portland cement include normal, early strength, very early strength, moderate heat, low heat, and sulfate resistance. Examples of the mixed cement include blast furnace cement, silica cement, and fly ash cement. Examples of the ecocement include ordinary ecocement and fast-curing ecocement. Examples of the other cements include white Portland cement, super fast cement, grout cement, oil well cement, and low heat cement.

[Method for preparing anhydrous gypsum composition]
The addition amount of the alkaline substance differs depending on the content of acid contained in the hydrofluoric acid byproduct gypsum with respect to 100 parts by mass of the hydrofluoric acid byproduct gypsum, and at least 500 parts by mass of neutralizing the content of this free sulfuric acid. Add the following:
When 2.5 parts by mass of water is added to 1 part by mass of the anhydrous gypsum composition to form a suspension, the anhydrous gypsum composition is prepared so that the pH of the liquid is 4.5 or more. This is strongly acidic when the pH of the above anhydrous gypsum composition is 4.5 or less, which causes corrosion of transportation equipment, transportation equipment, piping, mixers, pulverizers, classifiers, etc. Problems such as broken bags, corroded iron melting tanks for hardeners, corroded inexpensive iron injection pumps, corroded injection pipe tip devices, and corroded instrumentation-related equipment Has a point.
Therefore, in preparing the anhydrous gypsum composition, the alkaline substance is appropriately changed to raise the pH of the anhydrous gypsum composition to 4.5 or more. As a result, the sulfuric acid and fluorine content contained in the hydrofluoric acid byproduct gypsum can be stabilized and rendered harmless, handling safety, handling workability, working environment and the like can be improved at the same time.
Alkaline substances used in the present invention such as calcium, magnesium oxides, hydroxides, carbonates, bicarbonates, etc., double salts of these compounds, cement, etc. are added to the hydrofluoric acid byproduct gypsum in a high temperature state. Mix to ensure solid-state reaction with free acid, or add water or water vapor and cool to about 80-150 ° C, then further cool and remove water vapor, then crush and classify A harmless and extremely fluid powder is obtained. Therefore, when the anhydrous gypsum composition of the present invention is produced in a hydrofluoric acid production plant, the alkaline substances calcium, magnesium, potassium, sodium oxides, water used in the present invention for the hydrofluoric acid byproduct gypsum immediately after production are used. It is desirable to add compounds such as oxides, carbonates, bicarbonates, etc., double salts of the compounds, cement, etc. Of course, calcium, magnesium, potassium, sodium oxides are added to the hydrofluoric acid byproduct gypsum extracted by cooling. By adding a compound such as hydroxide, carbonate, bicarbonate, etc., double salt of the compound, cement, etc., mixing, grinding and classifying, the detoxified handling workability is good, A practical anhydrous gypsum composition having high fluidity is obtained.

The method for preparing an anhydrous gypsum composition includes the following raw material composition mixing step and pulverization / classification step.
(1) Mixing process The anhydrous gypsum composition of the present invention is a mixture of hydrofluoric acid byproduct gypsum and an alkaline substance with an alkaline substance that neutralizes the free sulfuric acid of the hydrofluoric acid byproduct gypsum to ensure a neutralization reaction. It is a process provided to create conditions to be performed.
Therefore, the mixture of hydrofluoric acid byproduct gypsum and the alkaline substance is provided in order to appropriately carry out the solid-state reaction between the free sulfuric acid contained in the hydrofluoric acid byproduct gypsum and the alkaline substance and to reliably carry out the neutralization reaction.
The addition amount of the alkaline substance with respect to 100 parts by mass of hydrofluoric acid byproduct gypsum can achieve the object of the present invention by adding from 500 parts by mass to 500 parts by mass necessary for neutralizing sulfuric acid contained in hydrofluoric acid byproduct gypsum. it can.
Below neutralization amount, corrosion of inexpensive mixers, pulverizers, classifiers, etc., corrosion of transport system of hydrofluoric acid byproduct gypsum, corrosion of piping system, broken bag of paper bag, corrosion of mixing tank, corrosion of injection equipment, etc. Therefore, it is not preferable because a large amount of investment is required for the equipment.
On the other hand, the amount of 500 parts by mass or more is preferable because no breakage of the paper bag is observed and the curing time can be shortened, but it is not preferable because the strength is reduced and wasted.
Calcium oxide, calcium hydroxide, calcium carbonate, cement, etc. exert a great effect when using an alkaline substance that is more than neutralized, but sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate , Potassium hydrogen carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, etc. are difficult to obtain a great effect, so if about 2 to 3 times the neutralization amount is used, the performance criteria stipulated by the present invention are sufficiently satisfied. can get.
As the mixing device, a tilting mixer, an omni mixer, a Hensyl mixer, a V-type mixer, a ball mill, a nauter mixer, a forced mixer, a disk mill, and the like can be used.
(2) Grinding / Classifying Step After properly mixing the hydrofluoric acid byproduct gypsum and the alkaline substance, it is provided to ensure that the performance criteria defined by the present invention are satisfied.
The grinder used in the present invention is a mixture of hydrofluoric acid byproduct gypsum and an alkaline substance, reliably performing a solid phase reaction between sulfuric acid and alkaline substance contained in the hydrofluoric acid byproduct gypsum, and storing an inexpensive paper bag For a long period of time, prevention of corrosion of piping and transportation-related equipment, prevention of corrosion of curing agent blending containers, and prevention of corrosion of injection pumps, injection equipment, instrumentation-related equipment, etc. It is a process provided not only for reducing the curing time but also for enhancing the gel strength. The particle size of the anhydrous gypsum composition used in the present invention can be 4500 to 15000 cm ² / g in specific surface area according to the Blaine method. Preferably it is 6500-8500 cm < ² > / g. Less than 4500 cm ² / g is not preferable because the strength is lowered. If it exceeds 15000 cm ² / g, the effect of shortening the curing time and enhancing the gel strength is small, and the cost for grinding and classification becomes expensive, which is not preferable.
Examples of the pulverizer used in the present invention include a ball mill, an atomizer, a roller mill, a roller press, a jaw crusher, and a top grinder.
As a classifier used in the present invention, a sieve for separating particles into large particles and small particles can be used.
Examples of the classifier include a forced vortex classifier, a semi-free vortex classifier, a vibration sieve, and an ultrasonic vibration sieve.

[Surfactant]
The surfactant used in the present invention is used for viscosity reduction and homogenization of the curing agent solution, elimination of fluctuations in gel time, improvement of consolidation efficiency, and the like.
As the surfactant of the present invention, those usually used as a cement admixture can be used.
As a kind of surfactant, a nonionic or anionic surfactant can be mentioned. Many types of nonionic or anionic surfactants are listed, but those commercially available as water reducing agents for concrete, such as lignin sulfonate surfactants, oxypolycarboxylates Surfactants, melamine sulfonate surfactants, highly condensed triazine sulfonate surfactants, naphthalene sulfonate surfactants, polyoxyethylene nonylphenyl surfactants, polyethylene glycol alkyl ether surfactants An agent or the like is preferable.
The lignin sulfonate surfactant is an alkaline (earth) metal salt of lignin sulfonic acid or various derivatives such as these formalin condensates. Examples of commercially available products include Sun Extract P252 (Nippon Paper Chemical Co., Ltd.). ))).
Oxypolycarboxylate-based surfactants are various derivatives such as addition or condensation polymer of alkali (earth) metal salt of a compound having a carboxy group, and commercially available products include, for example, Floric SF ( ) Manufactured by Floric).
The melamine sulfonate surfactant is an alkaline (earth) metal salt of melamine sulfonic acid or various derivatives such as a formalin condensate thereof. Examples of commercially available products include SMF-PD (Nissan Chemical Co., Ltd.). ))).
Naphthalene sulfonate-based surfactants are various derivatives such as alkali (earth) metal salts of naphthalene sulfonic acid and alkylallyl sulfonic acid or their formalin condensates, and examples of commercially available products include Mighty 100 (Kao). Among these, the lignin sulfonate surfactant is particularly preferable because it is inexpensive.
The amount of the surfactant used is difficult to specify depending on the type of the curing agent, the concentration of the curing agent suspension, and the type of the surfactant used, but the total amount of the anhydrous gypsum composition and the curing acceleration enhancer is 100 parts by mass. It is 0.35 or more and 1.25 mass parts with respect to. The amount is preferably 0.5 parts by mass or more and 1 part by mass or less. Less than 0.35 parts by mass is not preferable because the viscosity of the curing agent liquid is increased and the homogeneity is improved, but the permeability is deteriorated and the consolidation efficiency is lowered, and the curing time and strength are varied. In addition, when added in excess of 1.25 parts by mass, variation in curing time and strength is not recognized, but no decrease in viscosity of the curing agent liquid is observed, improvement in permeability is not observed, and waste. Therefore, it is not preferable.

[Defoamer]
The purpose of adding an antifoaming agent is to prepare a hardener solution with a surfactant added, and generate a large amount of foam on the surface of the hardener solution and in the solution, and it takes a long time to defoam, This is not preferable because the handling workability is deteriorated, and if the main agent liquid and the curing agent liquid are mixed, bubbles entrain and cure, leading to a decrease in strength and uneven curing time. The antifoaming agent of the present invention is added to solve the above-mentioned problems and to reduce the viscosity of the curing agent liquid and improve the permeability. The antifoaming agent used in the present invention contains an antifoaming agent usually used as a cement admixture.
Antifoaming agents include various alcohols such as higher alcohols, alkylphenols, diethylene glycols, dibutyl phthalates, water-insoluble alcohols, tributyl phosphates, polyglycols, silicones, and ethylene oxide-propylene oxide copolymers. A foaming agent is mentioned.
It is the range of 0.51 or more and 200 mass parts or less with respect to the usage-amount of the antifoamer used by this invention, and 100 mass parts of surfactant of this invention. Preferably they are 1 mass part or more and 100 mass parts or less. If the amount is less than 0.51 parts by mass, the curing agent solution can be homogenized, but since it takes a long time to defoam, workability is poor, and the curing time and the strength of the cured product vary, which is not preferable. When the amount exceeds 200 parts by mass, the surface of the curing agent liquid and the bubbles in the liquid disappear instantaneously, and the viscosity decreases and the penetrability improves, but the amount added is wasteful.

するのが良い。
これらの硬化促進増強剤は、 更に粉砕・分級して使用しても良い。その粒度は、ブレーン法に依る比表面積で３０００〜１２０００ｃｍ^２／ｇのものを使用できる。好ましくは４５００〜９５００ｃｍ^２／ｇ，更に好ましくは６５００から８５００ｃｍ^２／ｇである。３０００ｃｍ^２／ｇ未満は、強度が低くなるので好ましくない。１５０００ｃｍ^２／ｇ超えると均質化が図れるが粘性が高くなり浸透性が損なわれる等の性能面の向上が認められなく、結局、粉砕・分級の費用ばかり高価になり、不経済となるので好ましくない。[Curing acceleration enhancer]
The purpose of using the curing acceleration enhancer of the present invention is added in order to further shorten the curing time of the anhydrous gypsum composition as the curing agent and enhance the strength of the cured product.
The curing accelerator enhancer for use in the present invention, oxides of calcium, hydroxides, carbonates, can Rukoto cited sulfate or the like and cement, it can be used by adding one or more. Examples of the curing acceleration enhancer include commercial products for industrial use.
Calcium sulfate includes dihydrate gypsum, hemihydrate gypsum, type III anhydrous gypsum, type II anhydrous gypsum and other industrial gypsum and flue gas desulfurized gypsum, waste acid treated gypsum, phosphate gypsum dihydrate and half water Chemical gypsum such as salt and titanium gypsum can be dried, pulverized and classified by adjusting the pH to near neutrality.
Examples of the cement include Portland cement, mixed cement, and ecocement. Examples of Portland cement include normal, early strength, very early strength, moderate heat, low heat, and sulfate resistance. Examples of the mixed cement include blast furnace cement, silica cement, and fly ash cement. Examples of the ecocement include ordinary ecocement and fast-curing ecocement.
Examples of the other cements include white Portland cement, super fast cement, grout cement, oil well cement, and low heat cement.
The addition amount of the hardening accelerator is the Japanese Industrial Standard (JIS K-) as alkali silicate.

Good to do.
These curing acceleration enhancers may be further pulverized and classified for use. As the particle size, a specific surface area of 3000 to 12000 cm ² / g according to the Blaine method can be used. Preferably it is 4500-9500 cm < ² > / g, More preferably, it is 6500-8500 cm < ² > / g. Less than 3000 cm ² / g is not preferable because the strength is lowered. If it exceeds 15000 cm ² / g, homogenization can be achieved, but the improvement in performance such as increased viscosity and impairing permeability is not observed, and the cost of pulverization and classification becomes expensive and uneconomical. .

[Effect of curing agent]
As a result of investigation by the present inventor, the anhydrous gypsum composition of the above-mentioned hardener for ground stabilization chemical solution is mixed with an alkaline substance more than neutralizing the free sulfuric acid contained in the hydrofluoric acid byproduct gypsum. By using the anhydrous gypsum composition obtained by installing the pulverization / classification processing equipment, the paper product bag should not be broken for more than one year, the curing agent solution preparation tank should not be corroded, and the viscosity of the curing agent solution Is less than 5 mPa · s, foaming of the surfactant disappears in a short time by adding an antifoaming agent, and the curing time is prolonged by changing the amount of the main agent liquid used and the amount of anhydrous gypsum composition used. It becomes possible to make it within a few seconds of instantaneous setting from the 20 minute range, and the uniaxial compressive strength value of the cured body is from 0.01 N / mm ² or more of the practical strength of the long setting to 6 N / mm ² or more of the instantaneous setting. It has been found. Therefore, the anhydrous gypsum composition of the ground stabilizing chemical liquid curing agent of the present invention can obtain a desired curing time and strength when mixed with an aqueous alkali silicate solution without using expensive type II anhydrous gypsum, It can be applied to diversified and complicated ground construction and versatile earthwork, and at the same time, by-products can be reused, contributing to resource conservation and environmental considerations, and becoming an extremely environmentally friendly material. Was re-recognized.

[Ground stabilization chemicals]
The ground stabilization chemical | medical solution of this invention contains the hardening | curing agent mentioned above and the alkali silicate aqueous solution which is a main ingredient liquid (A liquid).
The alkali silicate, e.g., sodium silicate of _SiO 2 / Na ₂ O molar ratio is 2 to 4, _SiO 2 / Na ₂ O molar ratio can be used silica sol in the range of 4-6. Among them, No. 1 to 3 silicates defined in Japanese Industrial Standards (JIS K-1408) are preferable, and No. 3 sodium silicate is more preferable.

  The higher the alkali silicate concentration of the alkali silicate aqueous solution, the better in terms of increasing the strength. You may adjust suitably according to a construction method etc. For example, liquid A prepared using No. 3 sodium silicate prescribed in Japanese Industrial Standards (JIS K-1408) as sodium silicate and a curing agent liquid composed of an aqueous suspension containing a curing agent, in equal volumes. In the construction method of pouring into the ground while mixing, it is preferable to dilute No. 3 sodium silicate 60-120 parts by volume with water to 200 parts by volume.

The contents of the curing agent and the curing acceleration enhancer in the ground stabilizing chemical solution are increased when the curing time of the ground stabilizing chemical solution is shortened, and are decreased when the curing time is lengthened. If it is desired to increase the strength of the cured body, a large amount may be used. If it is desired to reduce the strength of the cured body, it may be used in a small amount.
A water suspension containing a main liquid (200 l) consisting of 100 l of sodium silicate No. 3 and 100 l of water defined in Japanese Industrial Standard (JIS K-1408), and the same amount of the curing agent of the present invention and a curing acceleration enhancer. When the ground is stabilized by a chemical solution (400 l) composed of a mixture with a curable liquid (200 l) composed of a turbid liquid, the anhydrous gypsum composition of the present invention is contained in the range of 10 to 120 kg in the curing agent liquid. It is preferable. It is preferable to contain a hardening acceleration enhancer in the range of 5 to 100 kg.

When injecting the ground stabilizing chemical solution into the ground, various injection tubes such as a single tube type, a double tube type, and a multiple tube type can be used.
In addition, as a method of injecting the ground stabilization chemical solution, a method in which the A solution and the B solution are mixed in advance and led to the injection tube, a mixing unit in which the A solution and the B solution are provided at the base of the injection tube, for example, a Y-shaped tube The method of mixing and guiding the liquid to the injection tube, the method of independently introducing the liquid A and the liquid B to the injection tube and mixing them in the injection tube, the method of introducing the liquid A and the liquid B independently to the injection tube, The method of merging and mixing in the ground while injecting into the ground.
These methods can be appropriately employed depending on the curing time and workability of the chemical solution.

EXAMPLES The present invention will be further described below with reference to examples, comparative examples, and reference examples, but the present invention is not limited to the following examples. Commercially available commercial products were used for the hydrofluoric acid byproduct gypsum, alkaline substance, surfactant, antifoaming agent, curing accelerator and the like used as the curing agent component.
The type II anhydrous gypsum shown in the reference example is obtained by calcining dihydrate gypsum in an electric furnace at 1000 ° C. for 3 hours, cooling, and then using a pulverizer and a classifier to obtain a specific surface area of 4500 cm according to the brane method. Three types of samples were prepared and used at ² / g, 6500 cm ² / g, and 7500 cm ² / g.
Examples, comparative examples, and reference examples are shown below. (Sample numbers 1 to 59) (Test numbers 1 to 83)
Alkaline substance was added to hydrofluoric acid byproduct gypsum and obtained by three kinds of preparation methods obtained through (1) mixing step, (2) pulverization, classification step, and (3) mixing step and pulverization / classification step. Table 1a, Table 1b, Table 1c, and Table 1d show the conditions for evaluating the properties of the paper bag, the pH of the mixing tank, the corrosion of the SPCC (cold rolled steel sheet), etc., for the anhydrous gypsum composition.
Regarding the curing agent liquid (B liquid), Table 2a shows the conditions for evaluating the defoaming properties and viscosity, the curing time and the uniaxial compressive strength of the cured body using the main agent liquid (A liquid) and the curing agent liquid (B liquid). It shows in Table 2b, Table 2c, Table 2d, and Table 2e.
The main agent liquid (A liquid) was prepared by charging 100 cc of No. 3 sodium silicate and 100 cc of water specified in Japanese Industrial Standard (JIS K-1408), and mixing and stirring.
As the hydrofluoric acid byproduct gypsum shown in Table 1a, Table 1b, Table 1c, and Table 1d, a lump-to-powder form from a rotary kiln was used, and the lump-to-powder form raw material was used as a raw material by pulverization and classification. As the alkaline substance, slaked lime, magnesium oxide, calcium carbonate, Portland cement, dolomite, potassium sodium carbonate, potassium hydroxide, and potassium hydrogen carbonate were used. In all cases, commercial products for industrial use were used.
The anhydrous gypsum composition was prepared as follows: (1) In the mixing step, hydrofluoric acid byproduct gypsum and an alkaline substance were simply mixed using a mixer. (2) In the pulverization / classification step, a sample was prepared by using a pulverizer and a classifier without mixing the hydrofluoric acid byproduct gypsum and the alkaline substance. (3) In the mixing step and the pulverization / classification step, hydrofluoric acid byproduct gypsum and an alkaline substance were added to the mixer and mixed, and then the sample was prepared using a pulverizer and a classifier.
The preparation of the anhydrous gypsum composition sample shows the conditions for studying and evaluating the above three types of preparation methods, and is shown together in Tables 1a, 1b, 1c, and 1d.

Sample Nos. 1 to 15 show conditions for examining the influence of the particle size of hydrofluoric acid byproduct gypsum, the influence of the preparation method of the anhydrous gypsum composition, and the influence of the brain value of the anhydrous gypsum composition. Sample Nos. 1 to 3 are flocculated to powdery hydrofluoric acid byproduct gypsum, Sample Nos. 4 to 6 are 30 mm or less, Sample Nos. 7 to 9 are 5 mm or less, Sample Nos. 10 to 12 are 1 mm or less, Sample Nos. 13 to 15 Was 90 μm or less, and the alkaline substance was Ca (OH) ₂ of 600 μm or less. Sample Nos. 16 to 36 set the particle size of the hydrofluoric acid byproduct gypsum to 5 mm or less, and showed conditions for examining the influence of the type of alkaline substance and the influence of the preparation method of the anhydrous gypsum composition. Sample numbers 16 to 18 are MgO 5 μm or less, sample numbers 19 to 21 are CaCO ₃ 75 μm or less, sample numbers 22 to 24 are Portland cement 3200 cm ² / g, and sample numbers 25 to 27 are MgCa (CO ₃ ) ₂ powders. Sample numbers 28 to 30 are KNaCO ₃ powder, sample numbers 31 to 33 are KOH granular, and sample numbers 34 to 36 are KHCO ₃ powder. Samples Nos. 1 to 36 were prepared by the mixing process of Sample Nos. 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, and 34. 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, and 35 are subjected to pulverization / classification process, and sample numbers 3, 6, 9, 12, 15, 18, 21, 24, 27 , 30, 33 and 36 were subjected to a mixing step and a pulverization / classification step treatment to obtain an anhydrous gypsum composition. Sample Nos. 37 to 44 use 100 parts by mass of hydrofluoric acid byproduct gypsum of 5 mm or less, and use 0 to 500 parts by mass of granular Ca (OH) ₂ as an alkaline substance to perform a mixing step and a pulverizing / classifying step. Regarding the influence of the addition amount by adjusting the brane value of the anhydrous gypsum composition to 8500 cm ² / g, Sample Nos. 45 to 53 were mixed with 1 μm or less hydrofluoric acid byproduct gypsum and 45 μm or less CaCO ₃ as an alkaline substance. The anhydrous gypsum composition is prepared by pulverizing / classifying step treatment. Regarding the influence of the specific surface area according to the brane method of the anhydrous gypsum composition, sample number 54 is an alkaline substance in 100 parts by mass of hydrofluoric acid byproduct gypsum of 1 mm or less. specific surface area due to Blaine method is the addition of Ca _(OH) 2 100 parts by mass of 12000 ² / g, mixing step and rows pulverizing and classifying step process , The specific surface area due to Blaine method is to prepare the anhydrite composition 10750cm 2 / ^g, the effect of the amount of the curing agent of this wireless water gypsum composition, Sample No. 55 hydrofluoric acid 1mm or less by-product gypsum 100 7 parts by mass of 600 μm or less of CaCO ₃ as an alkaline substance was added to parts by mass to prepare a mixing, pulverization and classification process, and an anhydrous gypsum composition having a specific surface area of 6500 cm ² / g based on the brane method was obtained. Sample No. 56 is the surface activity of the anhydrous gypsum composition with respect to the effect of a hardening accelerator using the special name of slaked lime, Portland cement, the special name of slaked lime and Portland cement, CaCO ₃ , CaSO ₄ .2H ₂ O, etc. In order to examine the influence of the amount of surfactant used, the amount of surfactant lignin sulfonate used and the amount of antifoam used, and the amount of antifoam used, hydrofluoric acid byproduct gypsum of 1 mm or less 7 parts by mass of 600 μm or less CaCO ₃ as an alkaline substance was added to 100 parts by mass, and the mixture was subjected to a mixing step and a pulverization / classification step to obtain an anhydrous gypsum composition having a brain surface area of 7500 cm ₂ / g. Sample Nos. 57 to 59 show the conditions for examining type II anhydrous gypsum as a reference example.

(1) Performance evaluation of anhydrous gypsum composition (sample numbers 1 to 59)
(A) Properties of the paper bag Add hydrofluoric acid byproduct gypsum to the paper cement bag, and add alkaline substances to the hydrofluoric acid byproduct gypsum. (1) Mixing process, (2) Crushing / classifying process, (3) Mixing process and crushing -The state after filling with the hydrofluoric acid byproduct composition obtained by using the classification step and storing it for one year was observed.
Evaluation ○: The property of the paper bag was broken for one year and was none.
Evaluation x: The property of the paper bag is broken or broken in less than one year.
(B) pH of the mixing tank
The pH of the suspension in the compounding tank was measured using a pH meter.
Evaluation (circle): The pH of the preparation tank was 4.5 or more.
Evaluation x: The pH of the mixing tank was less than 4.5.
(C) Corrosion of SPCC (cold rolled steel sheet) 190 cc of tap water was charged into a 200 cc mixing tank, a test piece having a SPCC (cold rolled steel sheet) size of 50 × 30 × 2 mm was immersed, and then hydrofluoric acid byproduct gypsum, An alkaline substance is added to hydrofluoric acid byproduct gypsum and charged with 30 g of anhydrous gypsum composition obtained by combining (1) mixing step, (2) crushing / classifying step, and (3) mixing step and crushing / classifying step. The state of the preparation tank was observed by leaving it for a day.
Evaluation ○: The properties of the mixing tank were left undisturbed for 1 day, but were not corroded.
Evaluation x: The properties of the mixing tank are corroded and left on standing for 1 day.

Sample numbers 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 38, 39, 40, 41, as apparent from Table 1a, Table 1b, Table 1c, Table 1d 42, 43, 44, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56 Anhydrous gypsum compositions are mixed with hydrofluoric acid byproduct gypsum and an alkaline substance, and then crushed and By performing the classification process, the properties of the paper bag, the pH of the preparation tank, and the performance evaluation of the corrosion of the SPCC all satisfied the specified values of the present invention. Performance comparable to that of the expensive type II anhydrous gypsum of sample numbers 57, 58 and 59 could be obtained.
Sample No. 37, to which no alkaline substance was added, failed to meet the performance criteria of the present invention even after the pulverization / classification step after the mixing step of the anhydrous gypsum preparation method of the present invention.
Sample numbers 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, and 34 obtained by treating hydrofluoric acid byproduct gypsum and an alkaline substance alone are defined by the present invention. The performance evaluation could not be satisfied.
Furthermore, sample numbers 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, and 35 obtained by performing the pulverization / classification step alone without the mixing step are the present invention. Could not satisfy the performance evaluation of the anhydrous gypsum composition defined by.

[2] Evaluation of curing agent liquid, curing time, uniaxial compressive strength of cured body (test numbers 1 to 87)
(1) Evaluation of curing agent liquid The evaluation results of antifoaming properties and viscosities were shown in Table 2a, Table 2b, Table 2c, Table 2d and Table 2e using a curing agent liquid (B liquid).
The main liquid was prepared by mixing 100 cc of No. 3 sodium silicate as defined in Japanese Industrial Standard (JIS K-1408) and 100 cc of water.
The curing agent liquid is 10-80 g of the anhydrous gypsum composition of the above sample numbers 1 to 56, 30 g of type II anhydrous gypsum of the sample numbers 57 to 59, 15 to 80 g of a curing acceleration enhancer, and 0. 09-1.0 g and 0-2.0 g of antifoam were prepared by suspending in water to a volume of 200 cc.
(A) Antifoaming property 180 cc of tap water of 20 ° C. is added to a mixing tank, and a surfactant and an antifoaming agent are added while stirring, and then a predetermined amount of limes and gypsum as curing agents are charged and stirred for 3 minutes. To do. The time required from when stirring was stopped until the foam disappeared was measured.
Evaluation (circle): The time required until defoaming was 10 seconds or less.
Evaluation x: The time required until defoaming was 10 seconds or more.
(B) Viscosity Viscosity of the curing agent liquid: Liquid temperature 20 ° C., 200 cc of the curing agent liquid is dispensed into a graduated cylinder and filled into a container. Next, the viscosity was measured with a B-type viscometer.
Evaluation (circle): The viscosity was less than 5 mPa * s.
Evaluation x: The viscosity was 5 mPa · s or more.
(2) Curing time and uniaxial compressive strength of the cured body The following main agent liquid (A liquid) and curing agent liquid (B liquid) were used and evaluated under the evaluation conditions for the curing time and the strength of the cured body. The evaluation results are shown in Table 2a, Table 2b, Table 2c, Table 2d and Table 2e.
The main agent liquid was prepared by mixing 100 cc of No. 3 sodium silicate as defined in Japanese Industrial Standard (JIS K-1408) and 100 cc of water.
The curing agent solution is 10-80 g of anhydrous gypsum composition of sample numbers 1 to 56, 30 g of type II anhydrous gypsum of sample numbers 57 to 59, 15-80 g of curing acceleration enhancer, and surfactant 0.09 as a curing agent. It was prepared by suspending in water to 200 cc using ˜1.0 g and 0 to 2.0 g of the antifoaming agent.
(A) Curing time Curing time was measured at a liquid temperature of 20 ° C. by measuring the time required from the start of stirring with a magnetic starter to the volume of the main agent liquid and the curing agent liquid until the stirring bar stopped. The time was within 20 minutes to a few seconds.
Evaluation x: Curing time was uncured for 1 day or longer.
(B) Compressive strength of hardened body A material of the hardened body formed by pouring an equal volume mixture of the main agent liquid and the hardener liquid into a cylindrical formwork (diameter 5 cm × height 10 cm) at a liquid temperature of 20 ° C. The uniaxial compressive strength one day after the age was measured.
1 day after material age Evaluation O: The uniaxial compressive strength value of the cured body was 0.01 N / mm ² or more.
Evaluation x: The uniaxial compressive strength value of the cured body was less than 0.01 N / mm ² .
(3) Comprehensive evaluation Comprehensive evaluation ○: Properties of anhydrous gypsum composition as a curing agent (properties of paper bags, corrosivity of SPCC (cold rolled steel plate), pH of preparation tank), properties of curing agent solution (curing agent solution) The evaluation items after 1 day after the defoaming property and the viscosity of the curing agent liquid using the curing agent), the curing time and the compression strength of the cured product were all good.
Comprehensive evaluation x: At least one of the evaluation items of the performance evaluation of the anhydrous gypsum composition as the curing agent, the properties of the curing agent liquid, the curing time and the cured body strength one day was x.

As is apparent from Table 2a, Table 2b, Table 2c, Table 2d, and Table 2e, the anhydrous gypsum composition is prepared by mixing, crushing and classifying hydrofluoric acid byproduct gypsum and an alkaline substance. As a curing agent, 0.01 to 1.0 part by mass of a surfactant and 0.005 to 2.0 parts by mass of an antifoaming agent, and 20 to 120 as the total of the curing agent and the curing acceleration enhancer. Test Nos. 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 38, 39 in which the content of the defoaming agent is 0.005 to 2.0 parts by mass. , 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 In the examples to be determined, the properties of the paper bag of the product, the pH of the mixing tank and the presence or absence of SPCC corrosion, the viscosity of the curing agent solution, the defoaming time of the curing agent solution, the curing time, and the uniaxial compressive strength of the cured product after 1 day Etc., all the performance criteria were satisfied at the same time. Further, the results of the examples of the present invention were inferior to the expensive type II anhydrous gypsum of test numbers 81, 82 and 83 shown as reference examples. Test number 37 was obtained by using the method for preparing an anhydrous gypsum composition of the present invention to obtain hydrous anhydrous gypsum having a break value of 8500 cm ² / g. However, since the alkaline substance of the present invention was not added, The performance criteria of the present invention could not be satisfied with respect to properties, pH of the mixing tank, corrosion of SPCC, and uniaxial compressive strength. On the other hand, when the anhydrous gypsum composition was prepared by treating the hydrofluoric acid byproduct gypsum and the alkaline substance only by mixing preparation, and processing by grinding and classification preparation, test numbers 1, 2, 4, 5, 7, 8, 10 11, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 65, 66, 67, 68, 69 At least one item deviates from the performance criteria, such as the properties of the paper bag, the pH and SPCC corrosion of the compounding tank, the viscosity of the curing agent solution, the curing time, and the uniaxial compressive strength after one day of the cured product, resulting in uncertain results. .
Regarding the influence of the particle size of the by-product gypsum, even with sample numbers 13 and 14 of 90 μm or less, the performance standard value defined by the present invention cannot be satisfied unless the preparation method of the present invention is applied.
If the preparation method of the anhydrous gypsum composition is only the mixing step and the crushing / classifying step, the properties of the paper bag of the product, the pH of the preparation tank, the corrosion of the SPCC, the curing time, In the uniaxial compressive strength etc. after 1-day curing, it deviates from the performance standard of the present invention, and an uncertain result is obtained.
Obtained by adding an alkaline substance Ca (OH) ₂ to 100 parts by mass of hydrofluoric acid byproduct gypsum and adding 10, 65, 100, 200, 300, 400, 500 parts by mass, and mixing and grinding / classifying preparation treatment In the case of the anhydrous gypsum composition having the test numbers 38 to 44, the setting time can be adjusted from 5 minutes or more of slow setting to several seconds of quick setting, and the strength is also 0.01 N / mm ^{2 to} 6 N, which is a practical strength. / Mm ² is possible, and it has the feature that it can be constructed more stably and more reliably for adapting to a wide range of applications and stabilizing the diversified and complicated ground. However, test number 37 with no addition of an alkaline substance can have a curing time of 20 minutes or longer, but it is difficult to make the uniaxial compressive strength 0.01 0.01 / mm ² or more of the practical strength. Hot.
Regarding the influence of the particle size of the alkaline substance, the performance standard of the present invention is satisfied by providing the anhydrous gypsum composition with a particle size of 5 mm or less and mixing and crushing / classifying preparation processing steps.
Regarding the influence of the particle size of the anhydrous gypsum composition, the specified value of the present invention is satisfied if the Blaine specific surface area of the test numbers 47, 48, 49, 50, 51, 52, 53 is adjusted to 4500-15000 cm ² / g. be able to. However, not rise effect so even if the 15000cm ² / g beyond the 12000cm ² / g, which is uneconomical to rise only cost of pulverization and classification.
Test numbers 45 and 46 indicate that the solid surface reaction is insufficient when the specific surface area based on the Bray method is less than 4500 cm ² / g even if the anhydrous gypsum composition of the present invention is used. It was not possible to satisfy all of the specified performance standards.
About the influence of the addition amount of an anhydrous gypsum composition, the performance standard which this invention prescribes | regulates by adding 10-80 mass parts is shown as the test number 54-59 showed the result examined using the sample number 54. Can be satisfied. Thereby, the result which has the characteristic which can construct more stably and reliably can be obtained by adapting to a wide range of applications and stabilizing the diversified and complicated ground.
Test Nos. 65, 66, 67, 68, and 69, which were investigated using five types of surfactants for the influence of the surfactant type, show good results in terms of permeability because the viscosity of the hardener solution decreases. However, the defoaming time becomes long and handling workability is deteriorated. The uniaxial compressive strength after one day has the disadvantage that it becomes harder and weaker because bubbles are involved and hardened, and it is difficult to obtain a constant value and the width of variation becomes large.
The results of examining the lignin sulfonate with respect to the influence of the addition amount of the surfactant are shown in Test Nos. 70, 71, 72, 73, 74 and 75. If the addition amount of the surfactant is 0.4975 to 0.8325 parts by mass with respect to 100 parts by mass of the total amount of the anhydrous gypsum composition and the hardening accelerator, the performance criteria of the present invention can be satisfied. However, since the addition amount of the surfactants with test numbers 70 and 71 is less than 0.4975 parts by mass, the performance criteria of the present invention cannot be satisfied.
Regarding the type of antifoaming agent, the silicon type is shown in test numbers 54 to 59, and the ethylene oxide-propylene oxide copolymer system is shown in test numbers 72 to 76. Both silicon-based and ethylene oxide-propylene oxide copolymer systems can satisfy the performance criteria of the present invention.
In Test Nos. 70, 71, and 75 in which the influence of the amount of antifoam used was examined, the defoaming time was longer than the performance standard of the present invention because it was 0.503 parts by mass or less based on 100 parts by mass of the surfactant. The handling workability and the uniaxial compressive strength after 1 day are disadvantageous in that it is difficult to obtain a constant value because the bubbles are involved and hardened, and the variation width becomes large. Since the test numbers 72, 73 and 74 are 0.503 parts by mass or more, the performance criteria of the present invention can be satisfied.
Test Nos. 76, 77, 78, 79, and 80 used in large amounts of antifoaming agent have an antifoaming time of 1 second or less and a viscosity of 3.5 or less, so that they can exert an effect on permeability and also have a compressive strength. Although there is an advantage that it can be increased, 200 mass parts is not so much improved in performance, and is wasted, so it is preferable to adjust by adding 100 mass parts or less.
Regarding the effect of the hardening acceleration enhancer, test number 60 uses slaked lime as a hardening acceleration enhancer for the anhydrous gypsum composition of sample number 55, and test number 61 accelerates the hardening of anhydrous gypsum for sample number 40. Portland cement was used as the enhancer, test numbers 62, 63, and 64 were used for the anhydrous gypsum composition of sample number 55, and the set accelerator 62 was used in combination with slaked lime and Portland cement. As a result of examination using calcium carbonate and test number 64 using dihydrate gypsum, the values satisfying all the performance criteria of the present invention were shown.

As a curing agent used for alkali silicate ground stabilization chemicals, an inexpensive by-product hydrofluoric acid by-product is an industrial by-product without using expensive type II anhydrous gypsum prepared by high-temperature treatment of hemihydrate gypsum and dihydrate gypsum. Effective use of raw gypsum, adding alkaline substance to the hydrofluoric acid byproduct gypsum, mixing uniformly to ensure solid-phase reaction, and subjecting the anhydrous gypsum composition to pulverization and classification preparation treatment It can be easily prepared, and the production apparatus, transport apparatus, injection apparatus, etc. of the anhydrous gypsum composition can be made inexpensive and competitive with excellent economic efficiency.
For this reason, it is possible to cope with complicated ground improvement and multi-purpose construction scenes, so that it becomes a hardener that can stabilize the ground more safely and surely, so that the industrial applicability is extremely high.

Claims (3)

More than the amount which neutralizes the free sulfuric acid contained in the hydrofluoric acid byproduct gypsum with respect to 100 parts by weight of the hydrofluoric acid byproduct gypsum (component (a)) and the hydrofluoric acid byproduct gypsum to 500 parts or more of the alkali silicate aqueous solution Anhydrous gypsum having a specific surface area of 4500 to 15000 cm ² / g based on the Blaine method obtained by adding one or more alkaline substances (component (b)) in an amount of less than parts by mass, mixing, pulverizing and classifying the mixture. The content of the surfactant (component (c)) is 0.35 or more and 1.25 parts by mass or less and (c) with respect to 100 parts by mass of the composition and the anhydrous gypsum composition and the hardening accelerator. The content of the antifoaming agent (component (d)) is 0.51 or more and 200 parts by weight or less with respect to 100 parts by weight of the component, and if necessary, the curing acceleration enhancer (component (e)) is dispersed in water. B water of the aqueous slurry is poured into the ground and hardened in the ground. A curing agent for ground stabilization chemicals, characterized by stabilizing the ground.   The ground stabilization according to claim 1, wherein the alkaline substance is a compound composed of oxides such as calcium, magnesium, potassium, sodium, hydroxides, carbonates, bicarbonates, etc., and double salts or cements composed of these compounds. Curing agent for chemicals.   The ground stabilization chemical | medical solution containing the hardening | curing agent for ground stabilization chemical | medical solutions of Claim 1 or 2, and an alkali silicate aqueous solution.