KR0185271B1 - Process for preparing special sodium silicate solution - Google Patents

Abstract

(1) preparing a 1: 1 water slurry of a low molar ratio sodium hydroxide 2 sodium silicate solution, (2) preparing an aqueous solution of NaOH in an amount equivalent to the above (1), and (3) 2) is added to a reactor equipped with a stirrer and stirred to form a homogeneous mixture, and (4) the mixed solution is reacted at 5-10 atm and 153-165 ° C for 4-5 hours. And a manufacturing method thereof.

Description

Special sodium silicate solution and its preparation method

The present invention relates to a special sodium silicate solution and a process for producing the same.

Conventionally, sodium silicate solution (disodium disilicate), sodium silicate No. 2 (tetrasodium pentasilicate) and sodium silicate solution (disodium trisilicate) have been known as sodium silicate solutions used in civil engineering construction fields have.

There are two methods of producing water glass (sodium silicate solution), dry and wet, but dry method is mainly used now. According to this method, firstly, the silica sand in a high order is washed with water, dried tablets (iron removal etc.), and then melted in a blending furnace in accordance with a predetermined ratio with soda ash to form a gamet. It regulates the molar ratio of Na ₂ O and SiO ₂ , adjusts the viscosity and specific gravity of the components, and filters the aqueous solution to manufacture and sell water glass. Sodium silicate solutions No. 1, No. 2 and No. 3 described above are commercially available as a sodium silicate solution (water glass). However, the No. 1 and No. 2 sodium silicate solutions have been used in civil engineering and construction, and a large amount of Sodium Silicate 3 solution called waterglass No. 3 is widely used. However, water quality No. 3 also has the following drawbacks.

First, the conventional water glass of No. 3 has a workable time too short.

In the former civil engineering construction, grouting is used to reinforce the soft soil. Injection is made by injection of water-3 (for convenience, A solution) and cement or cement milk (for convenience B solution) There is a way. According to this method, a perforated transverse stratum is pierced and a double tube is used to inject the solution A and the solution B into separate channels, and the injection tube is pulled out. Or a perforator having a stirrer blade attached to the tip of the perforator, the perforations and the soil in the hole are disturbed so that the injector is mixed well with the soil, and the injection pipe of the injection material is used as the double pipe as described above (A solution) and (B solution) are discharged from the tip of the tube at the same time, and a method in which stirring and mixing are simultaneously performed, and in the case of punching, the solution B is pierced and agitated to a predetermined depth while stirring the poured soil, And a method of drawing the injection tube while injecting and stirring the liquid.

That is, the soil particles and the B liquid are mixed at the time of punching, and at the time of the drawing, the A liquid is injected into the mixture of the soil and the B liquid. In the above-mentioned injection or injection stirring method, both of them react to cement or cement milk to become a gel and cure and cure by the reaction of water glass No. 3. The gelation time is not more than 5-6 seconds to several tens of seconds, and the content of cement ), The gelation time is shortened and the strength is increased. Therefore, at the present time point where a high strength is required, that is, a high strength is required, and the cement use amount becomes large, the time for the gelation and high crystallization (construction permitting time) is too short, so that the construction can not be continued.

Second, in the conventional water glass No. 3, the strength of the gelled solidified material in the grouting is lowered over time in the ground.

When water glass (No. 3 sodium silicate solution) is mixed with an acid or a metal salt aqueous solution, it immediately condenses (gels). In this case, the water glass, acid and metal salt aqueous solution related to gelation do not become 100% Irrespective of the water content, the water-soluble one remaining in the gelatinized cement product is eluted into the ground water, and the strength of the gel cement product becomes weak.

Third, in the conventional water glass No. 3, the volumetric shrinkage of the gelled solid matter is large.

The solidification of the solidification in the ground may cause the shrinkage or cracking of the groundwater due to the lowering of the groundwater level, resulting in a decrease in strength.

Therefore, the present inventors have found that the above-mentioned drawbacks can be solved by using a special sodium silicate solution instead of the No. 3 water glass in the cement and waterglass reinforced works widely used in civil engineering construction work. Specifically, the special sodium silicate solution of the present invention has the following characteristics.

(A) When cement, cement milk, water glass, cement, cement milk, waterglass and soil are gelled, the cementation time of the gel is further delayed, (B) The special sodium silicate solution of the present invention is used in the grouting using the water glass No. 3 and the metal salt aqueous solution, and the penetration effect is increased. Also, the strength of the solidified mixture with the soil is greatly weakened over time (C) the volume of the gelatinized cement product is small, and in particular, the special sodium silicate solution of the present invention and the gelled cement of the cementitious and earthy cement are used not only as a cement accelerator but also as a chemical reaction with the soil The strength of the preform can be increased.

That is, a method for producing a special sodium silicate solution according to the present invention comprises the steps of (1) preparing a 1: 1 water-based chelating solution of a second sodium silicate solution, (2) preparing an aqueous solution of NaOH in an equal amount to the above- (3) mixing the above-mentioned (1) and (2) into a reactor equipped with a stirrer, stirring the mixture to make a uniform mixture, and (4) reacting the mixture at 6 atm and at 153-165 ° C for 4-5 hours .

If the reaction pressure, temperature and time are less than 6 atm, 153 ° C and less than 4 hours, the product does not show the properties of the special sodium silicate solution, and the reaction pressure, temperature and time exceed 6 atm, There is a disadvantage in that it is economically inefficient.

Conventional sodium silicate solution has the following chemical structure.

That is, the chemical structure is a siloxane bond In which two (-OH) bonds to Si of ( ) When the atomic group is regarded as a monomer, it is a kind of polymer having -Na; -ONa at both ends thereof. However, the special sodium silicate solution prepared by the process of the present invention in the reactor has ( ) Block, which is then combined with Na and -ONa to form a monomer. In other words, that _{NaO · SiO 2 · XH 2 O} .

This monomer form has a favorable effect on the gel time delay or the properties of the reactants.

Here, the strong binding force of -Na on Na + of -Na or -ONa results in strong hydration. Therefore, Na reacts with Ca in Ca or earth particles in cement or cement milk to form Na ₂ O · SiO ₂ · XH ₂ O → CaO · SiO ₂ · XH ₂ O, and water glass (Na ₂ O · mSiO ₂ · XH ₂ O) It is understood from that when the molar ratio of Na ₂ O and SiO ₂ considering the various points that CaO · SiO ₂ · XH ₂ O in the same manner the binding molar ratio of CaO and SiO ₂ variety. This is a bar, CaO · SiO ₂ · a CaO of XH ₂ O in C, SiO ₂ a when a S, show the H ₂ O to H in the integrity of the cement concrete water CSH minerals (Bock (mineral Bouqe)) is It is believed that the addition of Ca in Ca (OH) ₂ as well as the Ca in Ca (OH) ₂ addition to the cement hydration increases the strength of Ca.

In the preparation of the special sodium silicate solution of the present invention, the ratio of silica sand and soda ash is adjusted so that the molar ratio of Na ₂ O and SiO ₂ becomes 1: 1 when the garnet is prepared as described above, by the making dissolved in water, but could also be a _{Na 2 O · SiO 2 · XH} 2 O, production equipment and production step of the nanyiseong and quality of the uniformity or the like is prepared, given the low mole ratio water glass of a commercial It is economical and reasonable to ensure the simplicity of the process and the uniformity of the quality by preparing a special sodium silicate solution as the intermediate raw material.

The second water glass (tetrasodium pentasilicate) used in the present invention has a molar ratio of about 1: 2.5, which is a low molar ratio as compared to the molar ratio of water glass No. 3 (disodium trisilicate) which is commonly used to 1: 3.

The gel time of the special sodium silicate solution prepared by the method of the present invention, the water leaching phenomenon of the gel solidified product, and the strength of the gelled cross-linked product are as follows.

Characteristic I: gel time

1 water dilution solution of a special sodium silicate solution prepared by the method of the present invention and a cement milk using the water glass No. 2 (sodium silicate solution No. 2) as a starting material, and a No. 1 water glass 1: 1 water A dilute liquid mixed with cement milk is mixed with an equilibrium type grout or a complete grout used for injecting a commercially available cement milk (cement suspension). Equal conditions are used at room temperature. The gel time was measured according to the measurement method, and the results are shown in Tables 1, 2 and 3 below.

Table 1: Effect of water-in-oil gel time control agent (quick-release type) on gel time of special sodium silicate solution system

Note: 1) No. 3 WG system is the No. 3 water glass

2) The special sodium silicate solution system

3) Among 100 cc of cement milk, 60 g of for-trend cement

4) No. 3 WG cement Milk 100cc contains the water-proofing agent used in the commercially available No. 3 water-glass cement suspension according to the manufacturer's specifications.

5) In the case of special sodium silicate solution, the blending amount of the rapid setting is the same as in 4).

As shown in Table 1, the quick-drying type of No. 3 WG system rapidly gels in 5 seconds-6 seconds. However, the reason why the special silicate solution system does not gel is that the kinds of composition components are the same,% is due to the different chemical structure .

Table 2: Effect of gel time control agent (complete type) on the gel time of special sodium silicate solution

Note: 1) No. 3 WG system No. 3 Water glass 1: 1 Water diluted solution

2) Special sodium silicate solution Special sodium silicate solution 1: 1 Water dilution

3) In 100cc of cement milk, 60g of for-trend cement is contained

4) No. 3 WG system or 100 cc of cement milk added complete grouting agent to be used for cement suspension in market in accordance with manufacturer's specifications.

5) Additional addition of complete grout equivalent to 4) in special silicate solution system.

As shown in Table 2, the final form of No. 3 WG system becomes gel in 76-79 seconds, but the gel time is more than 41 minutes in the special sodium silicate solution of the special sodium silicate solution system. % Or chemical structure.

Table 3: Effect of water and cement ratio on the gel time of special sodium silicate solution

Note: * The cement milk used in Table 3 has the same blending amount of cement milk, but the blending amount of cement in the cement milk, that is, the ratio of water / cement is 100%, 200% and 300%.

As shown in Tables 1, 2 and 3, the special sodium silicate solution (the special sodium silicate solution of the present invention) does not gel when mixed with the quenching type of the gel time adjusting agent of No. 3 water glass system in Table 1, It can be seen that the gel time was delayed nearly 40 times in the case of incorporating the complete type of the gel time adjusting agent of the water glass system, and the gel time delay rate is shorter than that in Table 1 because of Ca ⁺⁺ in the finished form. In Table 3, it can be seen that the gel time of the cement milk mixture of the special sodium silicate solution system is significantly slower than that of the No. 3 water glass, but it can be further delayed by adjusting the amount of cement. And the like. In addition, in Table 3, it can be seen that the gel time is longer as the W / C (water / cement ratio) is higher in the special sodium silicate solution system.

Therefore, it can be seen that the special sodium silicate solution has completely different characteristics from the previous ones of No. 1, No. 2 and No. 3 (sodium silicate solution).

Characteristic II: Properties in which the gelled solid matter does not leach in water

When the water-cured gelatinized cement in water No. 3 is cured in water, a white precipitate is formed on the bottom of the water tank of the curing water. This is caused by the SiO ₂ of the water solubility of the SiO ₂ or unreacted in the anti-caking water leaching. However, there is no precipitation in the special sodium silicate solution tank. In other words, there is no leaching phenomenon and there is no or little decrease in strength due to leaching.

Characteristic III: No. 3 The strength of the cemented product of the special silicate solution system is much higher than the strength of the water-based cementitious material.

In the cement mortar type of the previous No. 3 water glass system, the strength of the gelled solid is expressed only by the hardening of the cement. However, in the special siliceous soda solution system, in addition to the strength expressed by cement hardening, the combination of Ca ^{++ in the} soil and the special sodium silicate solution system has an effect of increasing the amount of cement used and increasing the strength.

In addition, the high strength of cement concrete is due to Ca (OH) ₂ produced by hydration reaction of cement, resulting in the formation of minerals of CaO, SiO ₂ and H ₂ O at various molar ratios, Reaction, gelation, coagulation and curing to give high strength reaction is caused by the reaction of special sodium silicate solution with Ca ⁺⁺ in the soil, that is, the reaction of Na ₂ O · SiO ₂ · XH ₂ O of special sodium silicate solution Na ₂ O Na is a substitute for Ca in the soil particles, and a mineral such as a baux derived from the mathematical reaction product of the cement is additionally produced, so that the strength is higher than the strength due to the cement in the cement milk originally mixed with the injection material. The uniaxial compressive strengths of the cemented milk, the special sodium silicate solution and the agglomerated mixed gelled solid of soil were measured according to a conventional method, and the results are shown in Tables 4-1 to 4-4.

Table 4-1: Uniaxial Compressive Strength of Cement Milk and Special Silica Sodium Solution and Mixture of Mixed Gravels

Addition: After the mold is manufactured, it is sealed in a plastic bag,

4-2: Uniaxial Compressive Strength of Cement Milk, Special Sodium Silicate Solution and Aggregate Mixture (Gray)

Table 4-3: Uniaxial Compressive Strength of Cement Density and Special Mixed Gypsum Cement Mixture of Sodium Silicate Solution and Coastal Sooty Soil

Table 4-4: Uniaxial Compressive Strength of Cement Milk and Special Silica Sodium Solution and Mixture of Soil (Soil) Mixed Gelled Cement

Extraction: The strength of the mold at 7 days was measured by compressive strength test within 10 minutes,

(A) After molding, after curing for 2 days in a humidifying machine (actually at 20 ° C)

(B) Cured for 5 days under water (20 ℃)

(C) Room temperature 20 ° C

As shown in Tables 4-1, 2, 3 and 4, the strengths of the specimens in Tables 4-1 and 2 are the strength of 1 day It is the strength of 7 days of curing underwater. On the basis of the test data in Tables 4-1, 2, 3 and 4, the uniaxial compression of the gelatinized cement product in the reaction with cement or cement milk (suspension type) of the No. 3 water glass system or the special sodium silicate solution system of the present invention The strengths are shown in the table below.

Table 5-1

Additional *

1. The strength at 1 day and 7 days in (A) is the uniaxial compressive strength of the homogeneous gel, and the strength at 28 days in (A) is the strength of the sand gel. The unit of strength is kg / cm ² , and the numerical value of strength is the average value of grouting strength of No. 3 waterglass in several domestic chemical engineering methods.

2. The strength of 1 day and 7 days in (B) is the strength of the soil gel using soil instead of sand gel.

3. B / A is the 7-day strength of (3) homoge gel and (7) the 7-day strength of the special gel of sodium silicate solution in (B) (A), which is 30 times stronger than the 7 day strength of (A), and 10 times stronger than the 28 day strength of (A) using sand gel.

Table 5-2 shows the comparison of the unconfined compressive strengths of the cement-type milk of the special sulphate solution system and the unconfined compressive strength of the cement-type milk of No. 3 water glass.

Table 5-2

Additional *

1. The table shows the strength of 28 days in L.W. (cement bentonite type).

2. As shown in Tables 5-1 and 5-2, the difference in strength is very large.

Therefore, the uniaxial compressive strength of the special sodium silicate solution system of the present invention is very large as compared with the 28-day strength of the sand gel of the No. 3 WG (sodium silicate solution) known so far.

Hereinafter, examples of preparation of the special sodium silicate solution of the present invention will be described as follows.

Example 1

(1) 800 cc of a 1: 1 aqueous solution of water glass No. 2 was prepared,

(2) 266.3 g of NaOH is dissolved in 680 cc of water to make an 800 cc aqueous solution.

(3) The same amounts as in the above (2) and (1) were metered and stirred into a high-pressure reactor equipped with a stirrer to prepare a homogeneous mixture. (4) The reactor was kept at 153-165 And reacted for 4-5 hours to prepare a special sodium silicate solution.

Example 2

When the water glass No. 2 in Example 1 is replaced with the No. 1 water glass and reacted, not only a lot of precipitates are formed, but also it takes a long time to completely remove the precipitate even if aged for a long time.

The characteristics of the special sodium silicate solution of the present invention are as follows: (1) The gel time is very long when the soil is strengthened by using 1: 1 water dilution solution and cement or cement milk as special soda as mentioned above. WG system, it is possible to perform high-strength grouting by using a large amount of cement regardless of the limit of cement usage. (2) Therefore, when pierced, injected, and stirred, it gelled to bite the rod of the perforator or injector, (3) a hardened body with high strength can be obtained, (4) the volume of the hardened body is shrunk or cracked even when dried, and the reliability is high and time (5) In particular, when a solution of a special sodium silicate solution and a salt of Ca or a solution of Ca chloride is used as an injecting agent, both It is easy to penetrate the soil with the blast furnace, and it is possible to strengthen the soil with high strength without using cement as the main source of Ca ⁺⁺ .

The special sodium silicate solution according to the present invention is characterized by (1) a solution type grouting in which an aqueous solution of a Ca salt or Ca chloride such as CaCl ₂ is injected, (2) a suspension using cement or cement milk (3) the above-mentioned (2) is injected as an injection agent and stirred to form a pillar-shaped cured body to reinforce the soil, and (4) it can be very usefully used in the production of a water resistant non-sintered earth brick.

Claims (2)

(1) A 1: 1 water dilution of a No. 2 sodium silicate solution was prepared, (2) An 8.3 molar aqueous solution of NaOH was prepared in an equal amount to that of the above (1) (3) The above-mentioned (1) and (2) were stirred into a reactor provided with stirring means to prepare a homogeneous mixture, (4) reacting the mixed solution at 6 atm and at 153-165 < 0 > C for 4-5 hours. A special sodium silicate solution prepared by the method of claim 1.