KR20020031267A - Antirust Agent including Sodium Silicate - Google Patents

Abstract

PURPOSE: Provided is an antirust agent mainly comprising sodium silicate, which does not disturb water echo system even when discharged to outside cooling system because it does not contain phosphate attributable to eutrophication. CONSTITUTION: In an antirust agent which is obtained by ion-exchange of sodium silicate(Na2O·SiO2·XH2O) having a SiO2/Na2O ratio of 2.0-3.2 in mole with one or more antibacterial metals, the antibacterial metal is selected from silver, gold, copper, and zinc. Further, a complex ion and a chelating agent are added. Furthermore, one or more compounds selected from organic antibacterial agents including chloride, amidazole, quaternary ammonium, iodine and natural antibacterial agents including hinokitiol, chitosan are added. The sodium silicate is prepared by adding 15-30% sodium hydroxide solution to amorphous silica powder(SiO2), adjusting to pH 10.5-11.5, and heating at 50-150°C while stirring.

Description

Antirust agent containing sodium silicate as a main ingredient {Antirust Agent including Sodium Silicate}

Most of the industrial water used in the industrial field is the cooling water, and the types of hot water, hermetic and open circulation cooling systems are used.

Cooling or closed circulation is not a big problem for cooling water management, but open-circulation releases latent heat of cooling water and some sensible heat to the outside for cooling, and it is used after being cooled and recycled. Done. In addition, the cooling water is contaminated, the surface of metal pipes are corroded by various corrosion factors, scales are stacked, and slime is generated under the conditions of microbial growth, which shortens pipe life, decreases the efficiency of heat exchangers and interrupts operation. It is very likely to cause deterioration.

The management status of the cooling water greatly affects the reliability and lifespan of the equipment, the safety operation of the process, and the improvement of productivity. Therefore, fouling due to pipe corrosion, scale generation and microbial breeding in such cooling water system is not shown. Should be prevented.

To this end, many companies use a mixture of corrosion inhibitors, scale dispersants, and microbial inhibitors, and there is a concern about overuse of unnecessary chemicals, and the discharged wastewater flows into the ocean to become a second pollution source.

Phosphates as current corrosion and scale inhibitors. Antiseptics based on silicates and molybdenum salts are used. Among them, phosphate is effective in metal pipe by small amount of input, but copper pyrophosphate, which is insoluble in water, is used when it is used in copper pipe, which may shorten pipe life. As it causes reproduction, globally, the total amount of water in the water is regulated to protect the environment. Molybdenum salt is less effective than other rust inhibitors and is expensive, so it is not used much.

Silicate is an environmentally friendly product and is widely used in the water quality management of tap water supply systems in developed countries such as the United States, Japan, and Germany, and is increasingly being used as water supply and industrial cooling water in Korea.

Korean Patent Laid-Open Publication No. 1999-57434 discloses a method for preparing a cleansing agent by mixing silicon dioxide, sodium hydroxide, sodium sulfite and phosphoric acid. However, this method is expensive because a large amount of chemicals must be added in addition to silicate, and there is a problem that it is not environmentally friendly.

In addition, Korean Patent No. 96-13482 has a disadvantage in that the manufacture of the cleansing agent, the natural silica (SiO ₂ ) crystals are melted at a high temperature of 1500 ° C. or more and manufactured by adding an additive, thereby increasing the manufacturing cost.

Accordingly, it is an object of the present invention to provide an environmentally friendly silicate rust inhibitor using sodium silicate.

It is another object of the present invention to provide a silicate rust inhibitor having corrosion prevention, scale suppression and microbial treatment functions at low cost.

In addition, another object of the present invention is to provide a method for producing a silicate that can be used as a major component of the rust preventive agent easily and inexpensively without the high temperature treatment of 1500 ℃.

In order to achieve the above object, the present inventor manufactures sodium silicate using SiO _{2 by-} product extracted from alumina from kaolin, and uses sodium silicate or commercially available silicate to produce antimicrobial inorganic metals such as zinc, silver, and copper. Was prepared by the ion exchange and the addition of natural and organic antimicrobial components to produce an antimicrobial rust inhibitor and a rust inhibitor (hereinafter referred to as "rust inhibitor") capable of complex water management.

The present invention is obtained by ion exchange with sodium silicate (Na ₂ O SiO ₂ XH ₂ O) having a SiO ₂ / Na ₂ O molar ratio of 2.0 to 3.2 with one or more metals having antibacterial properties such as silver, copper or zinc. Provided is a rust preventive agent composed mainly of sodium silicate.

In addition, the present invention provides a rust preventive agent comprising sodium silicate as a main component, wherein a complex ion and a chelating agent are added as stabilizers in the ion exchange process.

In addition, the present invention is a main component of sodium silicate, characterized in that the addition of at least one of an organic antimicrobial agent containing a chlorine, amidazole-based, quaternary ammonium-based, iodine-based compound and a natural antimicrobial agent, such as hinokithiol, chitosan It provides a rust preventive agent.

In addition, the present invention is prepared by adding 15-30% sodium hydroxide (NaOH) solution to amorphous silica (SiO ₂ ) powder and adding an appropriate amount of base to adjust the pH to 10.5 to 11.5 and stirring and heating to 50 ~ 150 ℃ It provides a rust preventive agent whose main component is sodium silicate.

A number of patents have been applied to a method of producing aluminum by acid treatment or dry grinding in kaolin (Korean Patent Publication No. 95-10811, Publication No. 78-150, etc.).

The inventors have inexpensively and easily sodium metasilicate using porous, amorphous silica (SiO ₂ ) powder extracted from alumina (Al ₂ O ₃ ) from kaolinite (Al ₂ O ₃ 2SiO ₂ XH ₂ O) ore and removing impurities. Na ₂ O SiO ₂ XH ₂ O) was prepared. However, in the production of the rust preventive agent mainly composed of sodium silicate of the present invention, the rust preventive agent of the present invention is prepared by using a porous amorphous silica component, commercially available silicate, and sodium silicate even if alumina is not necessarily extracted from kaolin by-products. It can manufacture.

Natural silica (SiO ₂ ) has a strong molecular crystal structure and dissolves only at a high temperature of 1500 ℃ or higher, while porous, amorphous silica (SiO ₂ ) powder from which alumina (Al ₂ O ₃ ) is extracted from kaolin is an amorphous (Amorphos) molecule. Has a structure.

Hereinafter, a method of preparing sodium silicate from porous amorphous silica powder, a method of exchanging ions of antimicrobial performance in sodium silicate, a method of adding an antimicrobial agent, and the like will be described in detail.

Sodium Silicate ₂ O SiO ₂ XH ₂ O) Manufacturing>

The amorphous silica powder is dried to evaporate moisture and crushed. Then, 300 to 500 g of SiO ₂ powder is added to 1 L of 15-30% sodium hydroxide (NaOH) solution, and gradually dissolved by stirring and heating at 50 to 150 ° C. At this time, the pH is adjusted while adding an appropriate amount of sodium carbonate (Na ₂ CO ₃ ) to about 10.5 ~ 11.5 and the SiO ₂ / Na ₂ O molar ratio is about 2.0 ~ 3.2 through component analysis.

When the concentration of sodium hydroxide is less than 15%, sodium silicate is not formed well, and when it exceeds 30%, the SiO ₂ / Na ₂ O molar ratio is not appropriate, so it is not suitable for use as a water treatment agent including a rust inhibitor.

In addition, the conditions required as product specifications of the water treatment agent or rust preventive agent are about pH 10.5 to 11.5, and at this time, the effect as a water treatment agent can be smoothly performed.

In addition, the SiO ₂ / Na ₂ O molar ratio is preferably 2.0 to 3.2, and within this range, sodium silicate is a monomer or a weight, well dispersed in water and ion exchange with antibacterial metal occurs smoothly, as well as the metal of the tube It can be substituted with the component to form a thin monomolecular film.

<Ion exchange>

A metal or metal compound such as silver, copper, or zinc having antibacterial ability to give a microbial treatment function after making a solution of sodium silicate (Na ₂ O SiO ₂ XH ₂ O) obtained as described above or commercially available sodium silicate in solution form Ion exchange using That is, 0.01 to 5 wt% of silver nitrate (AgNO ₃ ) solution was added to 1 L of sodium silicate solution having a SiO ₂ / Na ₂ O molar ratio of 3.0, and ion-exchanged at 70 to 90 ° C. for 6 to 12 hours while gradually stirring and heating. During this process, 0.1 ~ 0.5g of complex ion and chelating agent such as ammonium chloride (NH ₄ Cl) and EDTA (Ethylenediamine-tetraacetic) ₂ Na are added.

Sodium silicate is present in the aqueous solution as a monomer or a polymer, and the ion exchange of the antibacterial metal is performed by chemical equilibrium of metal ions such as silver (Ag +) in place of sodium (Na +) ions. However, these cations do not form stable bonds with silicates in aqueous solution, but simply dissolve as ions and float in aqueous phase.

(Present as monomer or polymer)

When a small amount of silver nitrate (AgNO ₃ ) solution is added, the antimicrobial activity is weak.In the case of excessive addition, some Ag + ions cause a precipitation of AgCl, etc. in an aqueous solution, or dissociate to an ionic state. (Black, etc.) phenomenon occurs. A stabilizer is added to prevent this phenomenon. The stabilizer reacts with unsubstituted silver (Ag +) ions to form a complex ion or chelate in the form of [Ag (NH ₃ ) ₂ ] ²⁺ to form a covalent bond with silicate. The solution becomes stable in aqueous solution and exhibits antimicrobial performance.

<Addition of organic and natural antibacterial agents>

1 to 5% by weight of an organic or natural antimicrobial agent was added to 1 L of the sodium silicate solution in which the antimicrobial metal was ion-exchanged, and mixed and reacted at 50 ° C. for 1 to 2 hours.

The organic or natural antimicrobial agent may be any kind as long as it can be mixed with a sodium silicate solution as having a property of inhibiting the growth of microorganisms or killing microorganisms when contacted with microorganisms. For example, organic antimicrobials such as chlorine, amidazole, quaternary ammonium or iodine compounds and natural antimicrobials such as hinokithiol, chitosan and the like can be applied to the present invention.

As described above, the anti-corrosive agent of the present invention has the ability to prevent corrosion, scale dispersion, dissolution degreasing of pipe contaminants, and microbial production. In other words, an electrically negative monomer or weighted silicate is injected into the water flowing through the water supply system and diffused throughout the system, and is absorbed on the metal surface to form a thin monomolecular film as shown below. prevent.

(M: metal)

In addition, the rust preventive agent of the present invention reacts with Ca ²⁺ , Mg ²⁺ ions, etc., which are metal impurities in an aqueous solution, and prevents the formation of scale.

CaCl ₂ + SiO ₂ + ₂ NaOH → CaSiO ₃ (dispersion) + 2NaCl + H ₂ O

(Mg: Substituted in Ca position)

Ca (HCO ₃ ) ₂ + SiO ₂ + ₂ NaOH → CaSiO ₃ (dispersion) + Na ₂ CO ₃ + CO ₂ + H ₂ O

(Mg: Substituted in Ca position)

The silicate of the present invention is a strong alkali having a pH of about 10.5 to 11.5, and has an excellent cleaning action, thereby promoting release from the metal surface by acting on rust, oil, scale of oxidization, slime, etc. After desorption, the silicate colloid is adsorbed onto the contaminant surface to form a chemically emulsified state. These contaminants must be removed because they will settle and deposit temporarily in the piping.

The anti-rust agent of the present invention is an ion-exchanged product of sodium silicate, and when a small amount is added to a water supply and cooling water system, the anti-rust agent exhibits the ability to inhibit the growth of bacteria and kill them.

Unlike organic antimicrobials, antimicrobial activity lasts for a long time because it is stable and has no volatility at high temperature and wide pH range, but the effect is rather weak and slow. Therefore, by adding two or more organic and natural antimicrobial agents to the product, the effect is fast and strong and lasts for a long time. It can manufacture.

Antimicrobial metal ions such as silver, copper, and zinc, which are dissociated from inorganic carriers, reach cell membranes of microorganisms by diffusion and are adsorbed to protein of cell membranes to destroy cell structure and bind to -SH group, which is a constituent amino acid. It inhibits and exerts ability to stop fungus. In addition, natural and organic antimicrobial agents are rapidly sterilized by destroying bacteria from the cell wall to the nucleus.

<Example 1>

Alumina was extracted from kaolin ore and 200-300 g of silicon oxide (SiO ₂ ) powder from which impurities were removed was slowly heated while stirring into 1 L of 25% sodium hydroxide (NaOH) solution.

A sodium metasilicate (Na ₂ O SiO ₂ XH ₂ O) solution was prepared by adjusting the pH to 10.5 while adding an appropriate amount of sodium carbonate (Na ₂ CO ₃ ) and stirring and heating at 80 to 120 ° C. for 5 hours.

Table 1 shows the result of component analysis of the sodium silicate by this invention.

Ingredient Specification Analysis Content (SiO ₂ ) 16.4% Constellation Colorless liquid Arsenic (As) Not detected Pb Not detected Cadmium (Cd) Not detected Mercury (Hg) Not detected pH 10.5

<Example 2>

0.1 to 10 g of silver nitrate (AgNO ₃ ) solution was dissolved in 100 ml of ionized water in 1 L of a sodium silicate solution having a SiO ₂ / Na ₂ O molar ratio of 3.0, and ion-exchanged at 70 to 90 ° C. for 6 to 12 hours while gradually stirring and heating. During this process, 0.1-0.5 g of ammonium chloride (NH ₄ Cl) was added.

<Example 3>

10 to 50 ml of the quaternary ammonium salt of the amine system was added to 1000 ml of the resultant of Example 2, followed by reaction with stirring and heating at 50 ° C. for 1 to 2 hours, followed by natural cooling.

<Example 4>

Five 500 ml beakers were taken with 100 ml of tap water, one was tap water itself, and the other four beakers were 0.1 ml of the rust inhibitor of the present invention obtained in Examples 1, 2 and 3, and 0.1 g of a phosphate of B company in Korea. After mixing the mixture, each of the steel materials of 2cm X 3cm size was placed in a beaker, immersed at room temperature for 1 hour and then taken out and left for 12 hours in a 50 ℃ thermostat to observe the presence of rust.

Wet Test Items Test result Tap water A lot of rust (maroon) Example 1 No call Example 2 No call Example 3 No call phosphate A little bit

<Example 5>

General bacterial solution was put in a certain amount in LB (Luria Bertani) plate medium and incubated for 40 hours in a 37 ℃ incubator. The number of viable cells of this culture solution was measured, and three samples were taken at 100 ml each, and the other one was incubated with 0.1 ml of the rust inhibitor of the present invention obtained in Examples 2 and 3, respectively, and the other two cells were changed after 24 hours. I looked at it. The number of viable cells was diluted 100-fold and inoculated in CASO agar medium and incubated for 48 hours in a 37 ° C. incubator to measure the number of microorganisms in each sample and multiply the dilution ratio.

division Viable count (pcs / ml) Early After 24 hours Culture 2 to 5 × 10 ⁵ 10 ^{6-10 7} Example 2 2 to 5 × 10 ⁵ 100 or less Example 3 2 to 5 × 10 ⁵ below 10

The rust preventive agent according to the present invention is an environmentally friendly product that does not contain phosphate, which effectively dissolves and removes corrosion prevention, scale dispersion capability and piping contaminants in water supply and cooling water systems, and grows microorganisms contained in the aqueous solution by antimicrobial agents. Suppress

By performing these functions as a single product, the rust preventive agent of the present invention does not require special water quality control, and can reduce waste of manpower and prevent excessive use of water treatment chemicals, thereby preventing secondary environmental pollution with cost reduction.

Claims (9)

An anticorrosive agent comprising sodium silicate as a main component, which is obtained by ion-exchanging at least one metal having antimicrobial activity to sodium silicate (Na ₂ O SiO ₂ XH ₂ O) having a SiO ₂ / Na ₂ O molar ratio of 2.0 to 3.2. The anti-corrosive agent according to claim 1, wherein the metal having antibacterial performance is silver, copper or zinc. The antirust agent according to claim 1 or 2, wherein a complex ion and a chelating agent are added as stabilizers. The silicic acid according to claim 1 or 2, wherein at least one of an organic antimicrobial agent containing a chlorine, amidazole type, quaternary ammonium type and an iodine compound and a natural antimicrobial agent containing a hinokithiol and chitosan are added. Antirust agent with soda as the main ingredient. The main component of sodium silicate according to claim 3, wherein at least one of an organic antimicrobial agent containing a chlorine, an amidazole type, a quaternary ammonium type and an iodine compound and a natural antimicrobial agent containing a hinokithiol and chitosan are added. Rust preventive agent. According to claim 1 or 2, Sodium silicate is added to the amorphous silica (SiO ₂ ) powder 15-30% sodium hydroxide (NaOH) solution and the appropriate amount of base is added to adjust the pH to 10.5 ~ 11.5 and 50 ~ 150 ℃ A rust inhibitor comprising sodium silicate as a main component, which is produced by stirring and heating. According to claim 3, Sodium silicate is added to the amorphous silica (SiO ₂ ) powder of 15-30% sodium hydroxide (NaOH) solution and the appropriate amount of base to adjust the pH to 10.5 ~ 11.5 and stirred to 50 ~ 150 ℃, heating An anti-corrosive agent comprising sodium silicate as a main component, which is produced by The method of claim 4, wherein the sodium silicate is added to the amorphous silica (SiO ₂ ) powder of 15-30% sodium hydroxide (NaOH) solution and the appropriate amount of base to adjust the pH to 10.5 ~ 11.5 and stirred to 50 ~ 150 ℃, heating An anti-corrosive agent comprising sodium silicate as a main component, which is produced by The method of claim 5, wherein the sodium silicate is added to the amorphous silica (SiO ₂ ) powder of 15-30% sodium hydroxide (NaOH) solution and the appropriate amount of base to adjust the pH to 10.5 ~ 11.5 and stirred to 50 ~ 150 ℃, heating An anti-corrosive agent comprising sodium silicate as a main component, which is produced by