KR20050056186A - A manufacturing method of inorganic binder for liquefied sodium-silicate - Google Patents

Abstract

The present invention relates to a method for producing an inorganic binder using liquid sodium silicate, and more particularly, by crystallizing sodium inorganic acid by adding and stirring a certain amount of acetic acid to liquid sodium silicate, there is no phenomenon of releasing water or water in the air. Inorganic binders with strong water resistance can be manufactured, and the manufacturing apparatus is simple and the process is simple, which can reduce the overall manufacturing cost, and does not use organic solvents that are harmful to humans and the environment. It relates to a manufacturing method of.

Description

A manufacturing method of inorganic binder for liquefied sodium-silicate}

The present invention relates to a method for producing an inorganic binder using liquid sodium silicate, and more particularly, to liquid sodium silicate, which is a liquid sodium silicate having stability against moisture by adding acetic acid as an acid solution in a predetermined ratio to generate sodium salts. It relates to a method for producing an inorganic binder using.

In general, sodium silicate is called sodium metasillica, sesqui-sillicate, ortho-sillicate, etc., depending on the ratio of Na ₂ O to SiO ₂ . More than 40 kinds of sodium silicate have been commercialized and marketed.

In particular, liquid sodium silicate, called water glass, is a viscous alkaline solution. The molar ratio of liquid sodium silicate in Korean Industrial Standard (KS M 1415) is 1: 2.064 ~ 4.300 for Na ₂ O and SiO ₂ . Has a composition.

This liquid sodium silicate is used as a grouting agent to improve adhesives or soft ground due to its inherent adhesive strength, and it is widely used due to its simple manufacturing process, simple equipment, and low production cost than other adhesives or grouting agents. have. In particular, unlike the organic adhesives before, during and after the manufacturing process has the advantage that does not cause pollution has attracted the spotlight in terms of environmental friendliness.

However, when liquid sodium silicate is used as an adhesive or grouting agent, sodium ions contained in sodium silicate easily react with water or water in the air to form salts such as sodium hydroxide. Thereby, a problem arises that the unwinding phenomenon occurs and the strength is lowered so that it cannot serve as a binder.

Because of these problems, some of them use a mixed binder in which carbon and zeolite are added to the liquid sodium silicate. However, the liquid sodium silicate is coated as a surface, so that the adsorption capacity is significantly lowered and the strength is lowered. There are still difficulties.

Therefore, the present invention is to solve the above problems, by adding and stirring a certain amount of acetic acid to the liquid sodium silicate to crystallize sodium inorganic acid with salt, which is resistant to moisture and water in the air, and the manufacturing apparatus is simple. The simple process can reduce the manufacturing cost and provides a method for producing an inorganic binder using liquid sodium silicate which is not only environmentally friendly, but also useful as an adhesive or grouting agent because it does not use organic solvents that are harmful to humans and the environment. For the purpose of

The present invention to solve the above object,

Temperature is 20 ~ 40 ℃, liquid sodium silicate is added to the reactor rotating at 20 ~ 200RPM, acid solution is slowly added, and stirred for 1 hour to produce a siliceous product containing crystallized sodium salt, the total weight of water Added to 20 to 30% by weight, followed by stirring at 20 to 40 ° C. for 3 hours to dissolve the sodium salt, and to add inorganic compound containing alkali earth metal at a predetermined ratio. In the manufacturing method of the binder,

The acid solution to be added to the liquid sodium silicate is acetic acid (CH ₃ COOH), the liquid is characterized in that the acetic acid is added to 5 to 10% by weight relative to sodium oxide (Na ₂ O) contained in the liquid sodium silicate It can be achieved by providing a method for producing an inorganic binder using sodium silicate.

Hereinafter, the present invention will be described in more detail.

First, acetic acid (CH ₃ COOH) is added to the liquid sodium silicate as an acid solution and stirred in a reactor rotating at 20 to 200 RPM, and acetic acid (CH ₃ COOH) is slowly added to the reactor into which the liquid sodium silicate is inserted. Next, the mixture is stirred for 1 hour while maintaining the temperature in the reactor at 20 to 40 ° C. to form gelatinous or transparent crystalline silicate.

That is, a binder prepared by producing a sodium salt as an crystalline phase and transforming a part of sodium silicate into a silicic state through the above reaction, so that sodium ions having adsorption capacity to moisture in the air are transformed into crystalline sodium salt. The release phenomenon due to moisture does not occur, and even after a long time after the adhesion does not drop the adhesive force has an excellent effect in water resistance.

At this time, it is more effective to use potassium oxide (K ₂ O) or lithium oxide (Li ₂ O) in the liquid sodium silicate, which can be improved even more when the prepared inorganic binder is used as an adhesive or grouting agent. Because there is.

The reaction process of the liquid sodium silicate and acetic acid (CH ₃ COOH) will be described in more detail through Scheme 1 below.

Na ₂ O SiO ₂ + 2CH ₃ COOH → SiO ₂ + 2CH ₃ COONa + H ₂ O

Referring to the case of using acetic acid (CH ₃ COOH) as an acid solution with reference to Scheme 1, after the reaction as silicon dioxide (SiO ₂ ) and sodium acetate (CH ₃ COONa), water (H ₂ O) and not dissociated The acetic acid (CH ₃ COOH) remaining without each is produced, and at this time, sodium acetate is present as crystals, thereby having stability against moisture.

When acetic acid is used as the acid solution as described above, the amount of acetic acid is most effective to add 5 to 10% by weight relative to sodium oxide (Na ₂ O) contained in the liquid sodium silicate, if the amount of acetic acid is 5% If it is added in less than% does not produce enough sodium acetate from sodium silicate, there is a problem that the stability of the moisture of the binder produced due to the presence of ionic sodium occurs.

On the contrary, when the amount of acetic acid is added in excess of 10% by weight, too much silicic acid product and the undissociated acetic acid produced after the reaction remain in excess, so that it is difficult to dissolve in the post-process and affects the stability, thus making it difficult to produce products. Because.

As described above, acetic acid is added to the sodium silicate as an acid solution, followed by stirring to produce a siliceous product including sodium salt. The water is added to 20 to 30% by weight based on the total weight so that the sodium salt crystallized into a solid can be dissolved. When the mixture is added and stirred at 20 to 40 ° C. for 3 hours to completely dissolve the crystals, an inorganic binder in an aqueous solution is prepared.

When the reaction of liquid sodium silicate and acetic acid is completed, water is added to form an aqueous solution, followed by calcium carbonate (CaCO ₃ ), calcium nitrate (Ca (NO ₃ ) ₂ ), magnesium chloride (MgCl ₂ ), and magnesium sulfate ( The addition of salts, oxides, and hydroxides containing alkaline earth metals such as MgSO ₄ ) and calcium hydroxide (Ca (OH) ₂ ) has a better effect. The compounds containing alkaline earth metals can be used as binders. This is because the surface crack strength increases due to bending strength, pellet type strength, and forced drying.

The compound containing the alkaline earth metal added as described above is suitably added in an amount of 0.1 to 0.5% by weight based on the total weight of the prepared inorganic binder. The amount is so small that the effect of increasing the strength is insignificant. On the contrary, when the amount is added in excess of 0.5% by weight, the alkali silicate compound which is not dissolved and suspended or precipitates is generated, so that the chromaticity of the manufactured silicate binder is turbid and bent. There is a problem that the strength or pellet type strength is not uniform for each measurement site.

In addition, an inorganic substance may be added before the reaction of sodium silicate and acetic acid to reinforce the physical properties of the inorganic binder, and for this purpose, after dissolving sodium tungsten (NaW0 ₄ ) and borax (NaB ₄ 0 ₇ ), etc. Can be.

Inorganic binders prepared by this method have stability against moisture or water in the air when used as an adhesive or grouting agent, which has good water resistance, can adjust the strength according to the use, and the manufacturing process is simple and the production equipment is made simple. It is possible to lower the environment, and it is environmentally friendly because water is used instead of harmful organic substances as a solvent.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are merely illustrative of the present invention, and the present invention is not limited by the following Examples.

<Example 1>

1 kg of liquid sodium silicate having a composition of 5.5% Na ₂ O, 2% Li ₂ O, and 22.1% SiO ₂ was added to a reactor rotated at 100 RPM, and water was added to 30% with respect to liquid sodium silicate. In order to prepare an inorganic binder by maintaining the temperature in the reactor at 40 ° C. and stirring for 3 hours, the surface crack and water resistance according to forced drying were measured by the following method with respect to the inorganic binder thus prepared. Table 1 shows.

Surface Crack

Inorganic binder was added to 30% of the total weight ratio and uniformly mixed with a mixture of carbon and zeolite 1: 1, and granulated in a sphere having a diameter of 2 mm / mm and placed in a dry oven (FO-600M). After insertion, hot air (90 ° C.) was forcibly applied, and the cracking degree of the surface due to instantaneous drying was examined as follows to measure the surface crack strength of each inorganic binder.

◎; No cracks at all

○; Fine cracks

△; With cracks

×; Severe cracking

Water resistance test

240 g of inorganic binder was added to 800 g of perlite and mixed uniformly. Then, the dried specimen prepared by molding 150 mm long, 80 mm long and 10 mm thick and drying at 130 ° C. for 60 minutes was filled with water. After precipitation for 24 hours in a filled 5 L container was examined the decomposition state to determine the water resistance for each inorganic binder.

◎; Not decompose in water

 ○; Slightly degraded in water

△; Decomposed in water

 ×; Completely decomposed in water

<Example 2>

Prepared in the same manner as in Example 1, except that acetic acid (CH ₃ COOH) was added to the liquid sodium silicate in small amounts to 3% of Na ₂ O of the liquid sodium silicate, and about 1 until crystals of the inorganic acid sodium salt were formed. After stirring for a period of time, water was added to the product including the crystals to 30% of the total weight and stirred again to completely dissolve the crystals to prepare an inorganic binder. Example 1 and the inorganic binder Surface cracks and water resistance according to forced drying in the same manner was measured and the measured values are shown in Table 1 below.

<Example 3>

Prepared in the same manner as in Example 2, an inorganic binder was prepared by adding acetic acid (CH ₃ COOH) to the liquid sodium silicate in small amounts to 5% with respect to Na ₂ O of the liquid sodium silicate, thereby preparing an inorganic binder. For the surface crack and water resistance measured by the forced drying in the same manner as in Example 1 and the measured values are shown in Table 1 below.

<Example 4>

Prepared in the same manner as in Example 2, an inorganic binder was prepared by adding acetic acid (CH ₃ COOH) to the liquid sodium silicate in small amounts to 7% with respect to Na ₂ O of the liquid sodium silicate to prepare an inorganic binder. For the surface crack and water resistance measured by the forced drying in the same manner as in Example 1 and the measured values are shown in Table 1 below.

Example 5

Prepared in the same manner as in Example 2, an inorganic binder was prepared by adding acetic acid (CH ₃ COOH) to the liquid sodium silicate in small amounts to 10% with respect to Na ₂ O of the liquid sodium silicate to prepare an inorganic binder. For the surface crack and water resistance measured by the forced drying in the same manner as in Example 1 and the measured values are shown in Table 1 below.

<Example 6>

Prepared in the same manner as in Example 2, an inorganic binder was prepared by adding acetic acid (CH ₃ COOH) to the liquid sodium silicate in small amounts to 15% of Na ₂ O of the liquid sodium silicate to prepare an inorganic binder. For the surface crack and water resistance measured by the forced drying in the same manner as in Example 1 and the measured values are shown in Table 1 below.

Acetic acid amount (%) Surface crack Water resistance Solubility of water in silicates Example 1 0  × △ Can be dissolved in water and manufactured as a binder Example 2 3 △  ○ Can be dissolved in water and manufactured as a binder Example 3 5  ○  ○ Can be dissolved in water and manufactured as a binder Example 4 7 ◎ ◎ Can be dissolved in water and manufactured as a binder Example 5 10 ◎ ◎ Can be dissolved in water and manufactured as a binder Example 6 15 - - Insoluble in water, not available as binder

As can be seen from Table 1, in the case of Example 1 in which acetic acid was not added and in the case of Example 2 in which acetic acid was added in an amount of 3% by weight relative to the sodium oxide in liquid sodium silicate, sodium ions in the manufactured silicate binder It was found that a large amount of this did not result in satisfactory surface cracking and water resistance. However, it can be seen that the water resistance is slightly improved because lithium oxide is contained in the liquid sodium silicate.

In addition, in the case of Examples 3 to 5 in which acetic acid was added in an amount of 5 to 10% by weight based on the sodium hydroxide in the liquid sodium silicate, the sodium ions contained in the liquid sodium silicate precipitated as sodium acetate salt after the reaction. It has the stability, the water resistance is good, and it can be seen that the surface crack measurement is well evaluated.

On the other hand, in the case of Example 6 in which acetic acid added 15% by weight to the sodium hydroxide of liquid sodium silicate, it was found that the silicic acid produced by the reaction was completely solidified and not dissolved in water, thus making it impossible to prepare as a binder. .

<Example 7>

For the inorganic binder prepared as in Example 5, the bending strength and pellet strength were measured by the following method, and the measured values are shown in Table 2 below.

Bending Strength Test

240 g of an inorganic binder was added to 800 g of perlite and uniformly mixed, followed by molding to 150 mm in width, 80 mm in thickness, and 10 mm in thickness, and drying at 130 ° C. to prepare a dry specimen of UTM (model: DTU-6207). Using the apparatus, load was applied at an average strain rate of about 5 mm / min using a three-point loading method, and then the maximum load indicated by the tester was measured, and the bending strength of the inorganic binder was expressed using Equation 1 below. It was.

Bending Strength (㎏f / ㎠) = 3/2 × L / bt ²

{P: Maximum load (N), L: length of specimen (cm), b: butterfly of specimen (cm), t: thickness of specimen (cm)}

Pellet type strength test

Inorganic binder was added to 30% of the total weight ratio and uniformly mixed with a mixture of carbon and zeolite 1: 1, and then formed into pellet type of 2 mm diameter and 5 mm length and dried at 120 ° C. The maximum load was measured using an IMADA (model: DPS-20) device, and pellet type strength of the inorganic binder was measured using Equation 1 for bending strength.

<Example 8>

Prepared in the same manner as in Example 5, when dissolving the silicic acid produced after the reaction with acetic acid in water to add calcium hydroxide (Ca (OH) ₂ ) to 0.05% of the total weight to prepare an inorganic binder, as described above Bending strength and pellet strength were measured in the same manner as in Example 7 with respect to the prepared inorganic binder, and the measured values are shown in Table 2 below.

Example 9

Prepared in the same manner as in Example 5, when dissolving the silicic acid produced after the reaction with acetic acid in water to add calcium hydroxide (Ca (OH) ₂ ) to 0.1% of the total weight to prepare an inorganic binder, as described above Bending strength and pellet strength were measured in the same manner as in Example 7 with respect to the prepared inorganic binder, and the measured values are shown in Table 2 below.

<Example 10>

Prepared in the same manner as in Example 5, but when the silicate produced after the reaction with acetic acid in water to add calcium hydroxide (Ca (OH) ₂ ) to 0.5% of the total weight to prepare an inorganic binder, as described above Bending strength and pellet strength were measured in the same manner as in Example 7 with respect to the prepared inorganic binder, and the measured values are shown in Table 2 below.

<Example 11>

Prepared in the same manner as in Example 5, when dissolving the silicic acid produced after the reaction with acetic acid in water to add calcium hydroxide (Ca (OH) ₂ ) to 1.0% of the total weight to prepare an inorganic binder, as described above Bending strength and pellet strength were measured in the same manner as in Example 7 with respect to the prepared inorganic binder, and the measured values are shown in Table 2 below.

Calcium hydroxide amount (%) Bending Strength (㎏f / ㎠) Pellet Strength (㎏f / ㎠) Transparency of the prepared inorganic binder Example 7 0 170 125 - Example 8 0.05 172 128 All calcium hydroxide is dissolved and transparent Example 9 0.1 182 135 All calcium hydroxide is dissolved and transparent Example 10 0.5 202 155 All calcium hydroxide is dissolved and transparent Example 11 1.0 192 142 Opaque due to insoluble calcium hydroxide

As can be seen from Table 2, when compared with Example 7 in which calcium hydroxide is not added, in Example 8 in which calcium hydroxide was added to 0.05% by weight relative to the total weight of the inorganic binder, the bending strength and the pellet type strength were very low. You can see that there is no difference.

On the other hand, in the case of Examples 9 to 11 added so that the calcium hydroxide is 0.1% by weight or more relative to the total weight of the prepared inorganic binder, it can be seen that the bending strength and pellet type strength is significantly improved, but only in Example 11 In this case, all of the added calcium hydroxide is not dissolved, so that the color of the inorganic binder is turbid, and the bending strength or the pellet type strength is not uniform depending on the measurement site.

<Example 12>

1 kg of liquid sodium silicate having a composition of Na ₂ O: 5.5%, K ₂ O: 2%, and SiO ₂ : 22.1% was placed in a reactor rotated at 100 RPM, and 5 g of acetic acid (CH ₃ COOH) was slowly added dropwise to 100 g of water. Then, the mixture was stirred for about 1 hour while maintaining the temperature in the reactor at 40 ° C. until crystals of the inorganic acid sodium salt were formed.

Water was added to the product containing crystals as described above to 30% of the total weight, and stirred at 40 ° C. for 3 hours to completely dissolve the crystals to prepare an inorganic binder. Compression strength and elution amount of sodium oxide were measured in the same manner as shown in Table 3 below.

Compressive Strength Test

70 kg of inorganic binder and 130 kg of water and 120 kg of cement and 80 kg of water were simultaneously poured into a circular frame of 5 cm in diameter and 5 cm in height, mixed before gel time, and cured. After the solids were immersed in water and taken out after 1, 3, 7, 28 days, the compressive strength was measured by a universal testing machine (UTM).

Measurement of elution amount of sodium oxide

In accordance with KS M 1415, the solids prepared for the compressive strength test were soaked in water, and after 1, 3, 7, 28 days, 2 g of the water containing the solids was collected and diluted to about 100 ml, followed by 0.1% methyl orange indicator. One drop was added, titrated with 1N hydrochloric acid, 1 ml was added excessively, and then back titrated with 0.1 N sodium hydroxide solution to calculate the elution amount (%) of sodium oxide according to the following equation (2).

Elution amount of Na ₂ O (%) = {(ab x 1/10) x 0.031} / S × 100

{a: amount of 1N hydrochloric acid consumed in titration (ml), b: amount of 0.1N sodium hydroxide consumed in reverse titration (ml), S: weight of sample (g)}

Example 13

Prepared in the same manner as in Example 12, when dissolving the silicic acid produced after the reaction with acetic acid in water to add a magnesium chloride (MgCl ₂ ) to 0.05% of the total weight to prepare an inorganic binder, thus prepared The inorganic binder was measured in the same manner as in Example 12 and the elution amount of sodium oxide was measured and shown in Table 3 below.

Comparative Example 1

Inorganic binder prepared by adding and stirring 30% water to KS No. 3 liquid sodium silicate (9% Na ₂ O, containing 28.5% SiO ₂ ) was stirred in the same manner as in Example 45 in terms of compressive strength and sodium oxide. The elution amount of was measured and shown in Table 3 below.

Compressive strength over time (㎏f / ㎠) % Elution of sodium oxide over time 1 day 3 days 7 days 28 days 1 day 3 days 7 days 28 days Example 12 7.16 9.0 125 250 0.22 0.34 0.34 0.35 Example 13 0.4 6.8 102 155 0.22 0.37 0.38 0.39 Comparative Example 1 1.8 5.7 13.2 85 0.18 0.34 0.42 0.52

As can be seen from Table 3, in Examples 12 and 13 using the inorganic binder of the present invention as a grouting agent, it can be seen that the compressive strength is significantly increased compared to Comparative Example 1 using a general sodium silicate binder as a grouting agent, Especially after 7 days, it can be seen that the compressive strength is significantly different.

In addition, in the case of the amount of elution of sodium oxide, Examples 12 and 13 using the inorganic binder of the present invention as a grouting agent can be seen that much less elution than Comparative Example 1, which can be seen that much improved in terms of water resistance have.

As described above, in the method for producing an inorganic binder using liquid sodium silicate of the present invention, acetic acid is added to the liquid sodium silicate as an acid solution and stirred according to a predetermined amount to crystallize and solubilize sodium inorganic acid, thereby obtaining water or water in the atmosphere. It is possible to manufacture inorganic binders with strong water resistance without releasing phenomena, and the manufacturing apparatus is simple and the process is simple, which reduces the overall manufacturing cost. In addition, by adding a certain amount of a compound containing alkaline earth metal to improve the physical properties such as bending strength or surface crack strength due to forced drying, it is useful to various adhesives and grouting agents.

Claims (3)

Temperature is 20 ~ 40 ℃, liquid sodium silicate is added to the reactor rotating at 20 ~ 200RPM, acid solution is slowly added, and stirred for 1 hour to produce a siliceous product containing crystallized sodium salt, the total weight of water Added to 20 to 30% by weight, followed by stirring at 20 to 40 ° C. for 3 hours to dissolve the sodium salt, and to add inorganic compound containing alkali earth metal at a predetermined ratio. In the manufacturing method of the binder, The acid solution to be added to the liquid sodium silicate is acetic acid (CH ₃ COOH), the liquid is characterized in that the acetic acid is added to 5 to 10% by weight relative to sodium oxide (Na ₂ O) contained in the liquid sodium silicate Method for producing an inorganic binder using sodium silicate. The compound of claim 1, wherein the compound containing alkaline earth metal is calcium carbonate (CaCO ₃ ), calcium nitrate (Ca (NO ₃ ) ₂ ), magnesium chloride (MgCl ₂ ), magnesium sulfate (MgSO ₄ ), calcium hydroxide (Ca (OH ₂ ) A method for producing an inorganic binder using liquid sodium silicate, which is a salt, an oxide and a hydroxide containing an alkaline earth metal as in ₂ ). The method for producing an inorganic binder using liquid sodium silicate according to claim 1 or 2, wherein 0.1 to 0.5% of the alkali-containing compound is added to the total weight of the inorganic binder.