KR20010104437A - Preparing method of activated silicate for chemical grouting - Google Patents

Abstract

The present invention relates to a method for preparing an active silicate ground injection medicament, more specifically, 50 to 60 parts by volume of water glass and 40 to 50 parts by mixing water to provide a water glass aqueous solution; Providing an active reactant in which 8 to 12 weight of an alkaline earth metal salt compound and 88 to 92 weight of water are mixed; Mixing and spraying the water glass aqueous solution and the active reactant at a weight ratio of 5 to 6: 1 to obtain an active silicate chemical through a high shear line mixer; And it relates to a method for producing an active silicate ground injection drug solution comprising the step of mixing the active silicate chemical solution and an aqueous solution of cement in a volume ratio of 1: 1 to obtain an active silicate gel. The active silicate ground injection medicament according to the present invention has a shorter gel time when compared to the same conditions as a conventional water glass system, excellent engineering characteristics such as compressive strength and permeability coefficient, and significantly lower leaching due to a large amount of groundwater. Indicates.

Description

Preparing method of activated silicate for chemical grouting

The present invention relates to a method for preparing an active silicate ground injection chemical, and more specifically, a water glass (sodium silicate) -based chemical solution has been conventionally used for ground improvement such as ground reinforcement and order. As a result of the special reaction of the active reactants to the water glass to obtain the active silicate chemicals to form the active silicate gel, it has excellent engineering characteristics such as gel time, compressive strength, and permeability coefficient, and significantly lowers the alkali dissolution phenomenon due to water. The present invention relates to a method for preparing an active silicate ground injection chemical which has improved durability and other problems than conventional water glass-based chemicals.

Currently, the most common injection chemicals are water glass (sodium silicate) based liquids, which are divided into pure liquid type and suspension type chemicals using cement according to the injection conditions and purposes. Considering the low cost, it is recognized as a relatively excellent method in terms of economic improvement effect compared to economic feasibility.

Related prior arts include Korean Registered Patent No. 153238 (name: ground injection chemical), Korean Registered Patent No. 22435 (name: injection method and injection tube used therein), Korean Registered Patent No. 153217 (name: ground injection) Solution), Korean Registered Patent No. 50112 (Name: Ground Injection Method), Korean Registered Patent No. 197851 (Name: Ground Injection Chemical), Korean Patent Application No. 92-024865 (Name: Ground Injection Chemical), Korean Patent Application No. 81-3590 (name: ground injection method), and in particular, Korean Patent No. 153217, water glass and slag with a molar ratio of 2.5 or less, sodium aluminate and slag with a molar ratio of 10 or more, or water glass, aluminic acid Suspension type ground injection consisting of nats and slag, and cement and / or dispersant added to each of these ground injection solutions as needed to obtain high strength even in long gelling time with relatively low viscosity A chemical liquid is disclosed, and in Korean Patent No. 197851, it contains water glass having a molar ratio of 1.5 to 2.8, fine particle slag having an average particle diameter of 10 µm or less and a specific surface area of 5,000 cm 2 / g or more as an active ingredient. Disclosed is a ground injection chemical solution containing cement and / or lime, and a calcium eluate adjusting agent as necessary. In addition, Korean Patent Application No. 92-024865 discloses a water glass-based ground injection chemical containing water glass, acid root and metal ion blocker as an active ingredient.

However, the water glass-based chemical solution has a phenomenon that as the elution proceeds from the injected solidified body by adsorbed water and free water in the soil soil after the solidification of the ground injection, eventually all the injection material is leached, that is, the durability is weak. Not only are there safety issues due to loss, but there is also groundwater contamination. In addition, the water glass-based chemical solution may be delayed in the gelation time when diluted by a large amount of groundwater at the time of the ground injection may not achieve the desired injection effect, there is also a problem in that it is lost due to the solidification.

Therefore, in advanced foreign countries, it is known that the chemical solution, such as silica sol, which improved its properties by chemically modifying and modifying water glass, has improved many problems in durability, water pollution, etc. There is a problem that cannot be fully implemented. This chemical liquid can be classified into acidic silica sol and neutral silica sol. The former is prepared by field production of water-stable silica sol solution in an appropriate manufacturing plant using an excessive acidic acid such as sulfuric acid. There is a problem because it handles dangerous substances such as sulfuric acid as raw materials. On the other hand, the latter has a problem in that the production process is complicated by pretreating water glass with a specific acidic agent and removing and concentrating by-products by ion exchange resin or membrane filter, thus producing and supplying in a separate factory. There is a disadvantage of low economic efficiency.

In order to solve the problems of the conventional water glass-based chemical injection method described above, while maintaining all the advantages of the water glass-based chemical injection method, problems in terms of quality, namely, leaching due to groundwater and unsolidification The present invention has been completed as a result of repeated research into a method of preparing a new chemical liquid that does not have a phenomenon and is simply manufactured and applied in the field.

Therefore, the object of the present invention is to inject the chemical solution for the ground improvement such as ground reinforcement and order, so that the gelation process is not only satisfactory to meet the engineering characteristics such as gel time, uniaxial compressive strength, permeability coefficient, but also alkali component leaching by groundwater. The present invention provides a method for producing an active silicate ground injection liquid which can be remarkably eliminated, which provides durability, economy, and environmental pollution prevention effect.

In order to achieve the above object, a method for preparing an active silicate injection liquid includes: mixing 50 to 60 volumes of water glass and 40 to 50 volumes of water to provide a water glass aqueous solution; Providing an active reactant obtained by mixing 8-12 weight alkaline metal salt compound with 88-92 weight water; Mixing and spraying the water glass aqueous solution and the active reactant at a weight ratio of 5 to 6: 1 to obtain an active silicate chemical through a high shear line mixer; And mixing the active silicate chemical solution and the cement aqueous solution in a volume ratio of 1: 1 to obtain an active silicate gel.

1 is a schematic diagram of an apparatus for preparing an active silicate chemical liquid according to the present invention.

2 is a schematic diagram inside a high shear line mixer of the device according to the invention.

Explanation of symbols on the main parts of the drawings

1: water glass dilution stirring tank 2: active reactant solution bath

3 and 4: Automatic proportional feeder for water glass and active reactants

5: injection nozzle 6: high shear line mixer

7: Product Storage Stirring Tank

8: Internal mixing structure of high shear line mixer 9: Conceptual diagram of decomposition in operation

10: conceptual diagram of conversion action 11: conceptual diagram of inversion

Hereinafter, the manufacturing method of the present invention will be described in more detail with reference to the accompanying drawings.

First, the method of preparing the active silicate should understand the gelation process by the reactant of water glass (sodium silicate). The commonly used method is a method of mixing and reacting diluted water glass and cement (LW method: Labiles Wasser glass), which simply reacts with the silicic acid of the water glass and Ca ions in the cement component, but in general, the reaction is slow and the quality is weak. The scope of application is limited. In order to make up for the shortcomings, there is a method of shortening the reaction rate (known as SGR method) using sodium bicarbonate, which is a quenching additive, which has a large influence on the reaction temperature conditions. Nevertheless, the two methods have an alkali dissolution phenomenon due to groundwater, which is a problem in durability.

Considering this reaction phenomenon, how to give the active state of water glass can be seen as the key in the gelation process. For this purpose, acid silica sol method using inorganic acids such as sulfuric acid and neutral silica sol method using specific inorganic salts and then ion exchange resin or membrane filter are relatively stable in quality. This dangerous and the latter has the disadvantages of complicated operation, low practicality and economic disadvantage.

Therefore, as a result of observing the gelation process in the present invention, as a first step, water glass first generates a colloidal silicic acid oligomer (sol state) as an intermediate, and in the second step, a silica polymer in which the oligomer is polymerized in a high molecular weight state ( Gel state). As a result of the research, the silicic acid oligomer, which is a stable intermediate for a relatively long time, can be made by using a special activation reactant which stably forms water glass into a colloidal form and by applying a finely dispersed mechanical system. As a result of this reaction with the aqueous cement solution, silicic acid oligomers were obtained in a high molecular weight polymer (gel state). Wherein the active material is an alkaline earth metal salt (MXn) represented by the molecular structure of MXn, M is an alkaline earth metal, Mg or Ca, etc., X is a halogen group, hydroxyl group or sulfate group, preferably Cl, OH or Is SO ₄ . In addition, n means the medicine represented by 1 or 2. Specifically, magnesium sulfate, magnesium chloride, calcium chloride, magnesium hydroxide, calcium hydroxide and the like were specially prepared by using one or more than one.

On the other hand, when describing a system for finely dispersing the water glass aqueous solution, it is also possible to make a water glass aqueous solution, and then to add the activating reactant constantly and to stir it at a high speed (2000 rpm or more). There may be a non-uniform quality, in the present invention was applied to the method and apparatus as shown in Figures 1 and 2, it was possible to produce a good quality active silicate chemical at a lower cost of the device.

That is, referring to FIG. 1, 50 to 60 volumes of water glass and 40 to 50 volumes of water are mixed in a water glass dilution agitation tank 1 to obtain a water glass aqueous solution, and 8 to 12 weights in an active reactant solution tank 2. An active reactant obtained by mixing an active substance with 88 to 92 weight of water was obtained, and then the aqueous glass solution and the active reactant were mixed at a weight ratio of 5 to 6: 1 through an aqueous glass solution and an automatic active reactant proportional transfer device (3, 4). It was possible to obtain a stable and uniform fine active silicate chemical liquid by spraying using a spray nozzle 5 to pass a high shear line mixer 6 having a specially designed and manufactured internal mixing structure. The internal mixing structure of the high shear line mixer 6 is shown in FIG. In FIG. 2, reference numeral 8 denotes a mixed structure in which the terminals twisted 180 ° in the left and right directions in the tube are embedded at 90 ° and the length is about 1.5 times the diameter D, and reference numeral 9 is a conceptual diagram of the decomposition during operation. , 10 is a conceptual diagram of the switching operation in operation, and 11 is a conceptual diagram of the reversing operation in operation.

Since the general ground injection chemical is an activated oligomer and has a characteristic of being cured when stored for a long time, the present invention simplifies the mixing process to enable field production as shown in FIG. It is characteristic that we did not have any problem.

According to the present invention, the concentration of water glass in the water glass aqueous solution is preferably from 50 to 60 volumes, and less than 50 volumes may result in poor quality due to low solids content. This tends to be difficult to control the manufacturing process. In addition, the amount of the alkaline earth metal salt, which is the active substance in the active reactant, is preferably 8 to 12 wt%. If it exceeds 12 wt%, agglomeration may occur, which may adversely affect the quality, and less than 8 wt% may cause gelation. . In addition, the mixing ratio of the water glass aqueous solution and the active reactant is preferably 5 to 6: 1 by weight, wherein when the mixing ratio of the water glass aqueous solution is less than 5, entanglement may occur. It tends not to be complete.

In the gelation of the active silicate chemical thus obtained, gelation is performed by mixing with a cement solution as in the conventional method for preparing a water glass-based chemical solution. In other words, an active silicate gel is obtained by spray injection of an aqueous solution of cement composed of 50 weight cement and 50 weight water and the active silicate chemical at a volume ratio of about 1: 1. As a result of testing the product, there were engineering characteristics such as shortening of gel time, excellent compressive strength, and permeability coefficient, and it showed that there is almost no alkali leaching phenomenon shown in the conventional water glass gel.

Sodium bicarbonate was used as the water glass-based method (SGR method) in the amount of 9 to 13 wt.% Based on the aqueous solution of cement, and the gel time became several seconds, so that the active silicate injection liquid could be arbitrarily adjusted. It was confirmed to have a characteristic.

Hereinafter, the method of preparing the active silicate chemical liquid according to the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following examples.

First, an active silicate chemical was obtained, and a comparative experiment was performed with the active silicate gel and the conventional water glass gel by the chemical as follows.

Example 1

50 volume water and 50 volume water glass are mixed in the stirring tank to make an aqueous glass solution, and then 10 weight percent magnesium sulfate is dissolved in 90 weight water in another stirring tank to prepare an active reactant solution. The aqueous glass aqueous solution and the active reactant solution were transferred to a high shear line mixer through a spray nozzle at a weight ratio of 5.7: 1 to continuously obtain the active silicate chemical liquid, which was stored and used in a storage tank equipped with an agitator (see FIGS. 1 and 2). ). The active silicate chemical solution obtained above and 50 weight cement (water remaining) were simultaneously mixed and gelled in a volume ratio of about 1: 1 to obtain an active silicate gel.

Example 2

The active silicate gel was obtained in the same manner as in Example 1 except that the active silicate chemical was obtained by high speed stirring (2,000 rpm) using a general reactor instead of the high shear line mixer.

Comparative Example 1

A water glass aqueous solution diluted with 50 volumes of water and 50 volumes of water glass and 50 weight cement (remaining water) in a stirring vessel were mixed and gelled at a volume ratio of about 1: 1 to obtain a water glass gel.

Example 3

An active silicate gel was obtained by mixing and gelling an active silicate chemical solution obtained in Example 1 with a cement mixture composed of 30 weight of cement, 12.5 weight of fastener sodium bicarbonate and the remainder in a volume ratio of about 1: 1.

Comparative Example 2

A water glass gel was obtained in the same manner as in Example 3, except that the water glass aqueous solution of Comparative Example 1 was used instead of the active silicate chemical solution.

Gel Examples, Uniaxial Compressive Strength (KSF 2314), Permeability Coefficient (KSF 2322) and Alkaline Component Leaching (Atomic Absorption Method) of Examples 1, 2 and Comparative Example 1, and Examples 3 and 2 Test measurements are shown in Table 1 below. For reference, in the case of Example 3 and Comparative Example 2, the sodium bicarbonate was separately tested for the use of 9 weights, and only the gel time was described, and other physical properties obtained similar results.

Test Items Example 1 Example 2 Comparative Example 1 Example 3 Comparative Example 2 Remarks Gel time (sec) 50 45 60 9 (41) 16 (52) () Uses 9 weight of quick payment Uniaxial Compressive Strength (kg / cm ² _, σ ₂₈ ) 27.1 26.2 18.5 12.6 11.7 Permeability coefficient κ (cm / sec) 4.3 × 10 ^-8 3.6 × 10 ^-8 1.7 × 10 ^-7 2.9 × 10 ^-8 2.3 × 10 ^-7 Variable pitcher test Alkaline elution amount (mg / ℓ) 5.9 6.7 32.6 6.3 30.4 Permeate analysis after permeation test (Na)

Example 4

In Example 1, the active reactants were prepared in the same manner, except that the active silicate chemicals were prepared by specially preparing magnesium sulfate, magnesium chloride, magnesium hydroxide, calcium chloride, and calcium hydroxide, and the results are shown in Table 2 below. It was.

Example 5

Except for using the active silicate chemical solution obtained in Example 4 in Example 3, and was carried out in the same manner, the results are shown in Table 2 below.

Magnesium sulfate Magnesium chloride Magnesium hydroxide Calcium chloride Calcium hydroxide Remarks Chemical state A thin suspension Intermediate suspension Thick suspension Suspension condensation (after 1 hour) Suspension condensation (after 2 hours) Gel time (sec) Example 4 45 42 63 25 37 Ca-ion fastening phenomenon Example 5 9 10 17 6 7 Remarks (gel state) Similar property

The experimental results showed that the active silicate gelled more than the water glass, but the gel time was slightly shortened. The compressive strength of the water glass gel showed more than about 40 strength improvement over the active silicate gel. It is judged that a solid gel was formed. In addition, the permeability coefficient was also significantly improved, which is considered to be an effect of densification of gel tissue due to molecular weight enhancement. On the other hand, the measurement of alkali leaching (Na ⁺ ion detection) that can occur in groundwater shows that the leaching is remarkably lower than water glass gel (1/5), which affects the robustness and durability, as well as the environment such as groundwater. It is effective in preventing pollution. Experimental results using the fastener sodium bicarbonate show that the other engineering properties are similar to those of Examples 1 and 2, but are shorter than the gel time to form a safe gel that is not lost even when diluted with a large amount of groundwater. It is present. In addition, it can be seen that the gelation time can be satisfied by using the amount of the fastener in the range of 9 to 13 weight depending on the field conditions when the amount of the sodium bicarbonate used is 9 and 13 weight.

In addition, Mg and Ca ions in the alkaline earth metal salts, which are active reactants, are more coagulated in the active silicate chemicals, which is disadvantageous in workability, and in terms of SO ₄ , Cl, and OH groups. have. That is, magnesium sulfate, magnesium chloride, magnesium hydroxide, calcium hydroxide, calcium chloride, and the like are shown in this order.

Also, as can be seen from Table 1 above, a method of using a high shear line mixer designed and manufactured in the present invention (Example 1) rather than a method using a high speed rotating apparatus (2,000 rpm) (Example 2), This is excellent, especially in uniaxial compressive strength or alkali elution.

As described above, when the active silicate ground injection liquid of the present invention is used for ground improvement such as ground reinforcement and order, it is excellent in engineering characteristics such as gel time, compressive strength, and permeability coefficient, and the alkali dissolution phenomenon is considerably lowered for durability and It is also good for the environment. In addition, since it has a gelation rate that can cope with a large amount of groundwater in the ground, it can be applied in any case.

Claims (4)

Mixing 50-50 volumes of water glass and 40-50 volumes of water to provide a water glass aqueous solution; Providing an active reactant in which 8 to 12 weight of an alkaline earth metal salt compound and 88 to 92 weight of water are mixed; Mixing and spraying the water glass aqueous solution and the active reactant at a weight ratio of 5 to 6: 1 to obtain an active silicate chemical through a high shear line mixer; And Mixing the active silicate chemicals and the aqueous solution of cement in a volume ratio of 1: 1 to obtain an active silicate gel. The active silicate ground injection of claim 1 wherein the alkaline earth metal salt compound is represented by MXn, wherein M is Mg or Ca, X is Cl, OH or SO ₄ , and n is 1 or 2. Method for preparing a chemical liquid. The method of claim 1 or 2, wherein the alkaline earth metal salt compound is one or more selected from the group consisting of magnesium sulfate, magnesium chloride, magnesium hydroxide, calcium chloride and calcium hydroxide, the preparation of the active silicate ground injection pharmaceutical solution Way. The method of claim 1, wherein the aqueous cement solution contains 9 to 13 weight sodium bicarbonate as a fastener.