JPS6225561B2 - - Google Patents

Description

Detailed Description of the Invention This invention is a method of waterproofing deposits by coating the surface of the deposits when coal, coke, iron ore, minerals such as river sand, wood powder, etc. are deposited in open piles over a long period of time. , relates to a coating method for dustproofing, preventing oxidation due to air, etc.

Generally, in steel mills, gas plants, paper mills, etc., coal, coke, wood powder, etc. are often stored in open piles. However, during storage, these sediments tend to stir up dust in the wind, causing dust pollution in surrounding areas and causing sediment loss, and during rainfall, they flow into rivers and the sea, causing sewage. Excessive moisture content in sediments such as summer heat, coal, coke, iron ore, etc., causes disadvantages such as evaporative heat loss of water when the deposits are combusted.

An excellent method to solve these problems is to apply a paint containing the same or similar powder as the deposit to the surface of the deposit, thereby forming a water-insoluble coating after drying. has already been proposed. Although this method is extremely effective, there are variations in surface conditions such as moisture content and particle size of the deposit, and temperature and humidity at the time of coating.
The physical properties of the coating film formed vary depending on the weather, and the coating film cracks and flakes over time, which can adversely affect the waterproofing, dustproofing, and other effects.

The inventors believe that in the above-mentioned method, the filler, which is blended to impart thixotropic properties to the paint, occupies most of the paint components, and that this has a negative effect on the physical properties of the paint film, such as flexibility. As a result of intensive study to find a method to effectively cover the surface of the deposit without using such a filler, we found that the types of solutes, thickeners, etc.
The present invention was completed based on the knowledge that a paint with a viscosity and thixotropic index set within a specific range by selecting the amount, etc., can form a high-quality coating film with fewer of the above-mentioned problems.

That is, this invention prepares a coating paint that contains a solute that becomes water-insoluble after drying, has a viscosity of more than 500 centipoise and less than 25,000 centipoise, and has a thixotropic index in the range of 2 to 8, and deposits this paint in the open. The present invention relates to a method for coating open deposits, characterized in that the surface of the deposits is coated with a coating amount in the range of 0.5 to 5 kg/m ² .

The coating paint used in this invention contains a solute that becomes water-insoluble after drying, and is preferably a water emulsion type, but may also be an organic solvent type. The solute includes, in addition to the main resin component, optional components such as a film-forming aid, a thickener, and a freeze-thaw stabilizer.

Water emulsion resins include vinyl acetate polymers or their copolymers, acrylic acid ester, methacrylic acid ester polymers, or their copolymers with styrene, butadiene and styrene copolymers, butadiene and acrylonitrile. There are copolymers with Examples of organic solvent-based resins include styrenated alkyds, xylene resin-modified alkyds, and copolymers of vinyl chloride and vinyl acetate.

Among the optional components, specific examples of film-forming aids and thickeners include butyl cellosolve, butyl carbitol, butyl cellosolve acetate, carbitol acetate, hexylene glycol, dibutyl phthalate, dioctyl phthalate, etc. Examples of thickeners include methylcellulose, ethylcellulose, polyvinyl alcohol, hydroxyethylcellulose, carboxymethylcellulose, sodium polyacrylate, crosslinked acrylic acid polymers, casein, and starch. The proportion of these coating aids, thickeners, and other optional components used varies considerably depending on the desired viscosity and thixotropic index, but generally it is 10% by weight or less of the total solute including the resin content. It is preferable to do so.

In addition to the above-mentioned solutes, other components that can be incorporated into the paint include a fibrous reinforcing agent to improve the strength of the paint film and a water-repellent agent to impart water repellency to the paint film. Examples of the fibrous reinforcing agent include vegetable fibers such as cellulose, cotton, hemp, kapoku, and palm, animal fibers such as wool and feathers, and synthetic fibers such as nylon, vinylon, and tetron. The proportion of this reinforcing agent used is preferably up to 100 parts by weight per 100 parts by weight of the solute. In addition, as water repellent imparting agents, silicone,
Examples include paraffin and low molecular weight polyethylene, which can be used in a proportion of up to 3 parts by weight per 100 parts by weight of the solute.

This invention is characterized in that it does not contain inorganic or organic fillers such as powder or granules that are the same as or similar to deposits, but
The filler can be used in a proportion that does not impair the effects of the present invention and is generally less than 100 parts by weight per 100 parts by weight of the solute.

The coating paint of the present invention comprising such components has a viscosity of more than 500 centipoise and less than 25,000 centipoise at room temperature (20 to 30°C),
Preferably within the range of 1000 to 18000 centipoise, and its thixotropic index is 2 to 8, preferably 3
-6, respectively. This setting can be easily made mainly by selecting the type and amount of the resin and other solutes, especially the amount of the thickener.

When the above paint viscosity becomes 500 centipoise or less or the thixotropic index becomes less than 2,
If the paint applied to the surface of the deposit quickly penetrates into the deposit and a continuous film is not formed, and if the viscosity of the paint exceeds 25,000 centipoise or the thixotropic index exceeds 8, the painting process may be difficult. It has poor properties and lacks fluidity even when applied forcefully, resulting in uneven coating and making it difficult to form a continuous film.

In addition, in this specification, the thixotropic index is
This is the value obtained by dividing the viscosity when the same rotor is rotated 6 times by the viscosity when the same rotor is rotated 60 times using a B-type rotational viscometer. Therefore, the larger the thixotropic index, the higher the thixotropic properties of the paint.

The coating method of the present invention uses a coating paint having the above-described specific viscosity and thixotropic index, and coats the surface of the open deposit in an amount of 0.5 to 5 kg/m ² , preferably 1 to 3 kg/m ² . This is done by applying an appropriate method such as flow painting or spray painting, and then allowing it to dry naturally. here,
If the amount of paint is less than 0.5Kg/ ^m2 , uneven coating will occur due to insufficient amount, and if it exceeds 5Kg/ ^m2 , the surface layer of deposits will be washed away by the paint, causing landslides,
All of these methods are inappropriate as they may cause phenomena such as landslides.

The paint film formed on the surface of the deposit in this way dries while remaining on the surface without penetrating into the inside of the deposit because the paint used is highly viscous and highly thixotropic. As a result, a uniform, thin, continuous film is formed that is not affected by variations in surface conditions such as moisture content and particle size of the deposit, or by temperature, humidity, weather, etc. at the time of coating. Moreover, since this coating film does not substantially contain fillers, it has excellent coating properties and is particularly flexible, so that after the coating film is formed, the deposit itself may undergo some surface changes. Even if such changes occur, it follows these changes well, and due to this good followability, defects such as cracking and chipping of the coating film over time are reduced.

In this invention, the types of open deposits that can obtain the above effects include coal (powder), coke (powder), iron ore, minerals such as river sand, copper ore, limestone, bauxite and other metal ores. Or there are organic powders such as wood flour. These deposits generally have microscopic irregularities and undulations on their surface due to large and small sediment particles, and the difference in the density of the surface layer is large. The surface shape is subject to change.

It goes without saying that the coating method of the present invention can be applied directly to the surface of the deposit in the above state, but more preferably, it can be applied to the surface of the deposit in the above-mentioned state, but it is more preferable to apply the coating method to the surface of the deposit in the above-mentioned state. By performing appropriate pretreatment to modify the surface condition, the effects of the present invention can be better expressed.

Such pretreatments include, for example, (a) shaping and surface shaping, (b) compacting the surface layer by mechanical treatment or liquid spraying, and (b) spraying a pretreatment agent containing alcohol. Among these methods, one method can be used alone or, if necessary, two or more methods can be used in combination.

Method a involves, for example, rolling or registering the surface after piling up the piles, leveling the ground with a bulldozer, or devising a pile-up method that minimizes the formation of unevenness during the pile-up process. It flattens the top, fills cracks that occur on the slope, and eliminates surface irregularities, adjusting the shape of the deposit and making the surface smooth and uniform.

Method b involves compacting the surface layer of the deposit up to a depth of at most 30 cm from the surface by mechanical treatment or liquid spraying treatment to increase its dry density. The above-mentioned mechanical treatment means applying an external force such as impact, pressure, or vibration to the surface layer using a compactor, roller, vibrator, etc., and liquid spraying treatment means applying an external force such as impact, pressure, or vibration to the surface layer using a compactor, roller, vibrator, etc., and liquid spraying treatment refers to applying water, an organic solvent, or an appropriate amount of these liquids solutes and fillers,
This refers to dispersing or dispersing a binder (including cement), etc., using a spray, shower, discharge gun, etc., and then drying it.

Method c involves spraying a pretreatment agent containing monohydric alcohols, polyhydric alcohols, or their derivatives in water or other media at a concentration of 0.05% by weight or more on the surface of the sediment at a rate of 0.5 to 6 kg/ ^m2 . By spraying the liquid in a large amount, the wettability of the paint can be improved, the film forming temperature of the paint can be lowered and the film strength can be increased, and the surface layer can be compacted by spraying the liquid.

Examples of monohydric alcohols include methanol, ethanol, n-propanol, n-butanol, and isopropanol; examples of polyhydric alcohols include propylene glycol, dipropylene glycol, polyethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, and butane. Examples include diol, 1,5-pentanediol, glycerin, diglycerin, trimethylolpropane, and the like.

In addition, as derivatives of polyhydric alcohols, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoacetate, ethylene glycol Examples include diacetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monoisopropyl ether, and diethylene glycol monobutyl ether.

When the deposit surface is pretreated using methods a, b, and c above, microscopic irregularities and undulations on the surface are eliminated as much as possible, and the difference in density of the surface layer is reduced.
Furthermore, since the surface shape is stabilized, when the coating paint of the present invention is subsequently applied, a more uniform and thinner continuous film can be formed, and even better results can be obtained in terms of the aging properties of the paint film. be able to.

As detailed above, according to the present invention, since the paint used has high viscosity and high thixotropic properties, it is possible to form a uniform and thin continuous film on the surface of field deposits, and this paint film is flexible. Because of its richness, it closely follows slight changes in the surface of the sediment and does not cause cracks over time, thus maintaining the waterproofing, dustproofing, and anti-oxidation effects of open sediments for a long period of time. can be done.

Examples of this invention will be described below. In addition,
In the following, the term "part" means a capacitance part.

Example 1 A 0.3% by weight aqueous solution of propylene glycol was sprayed at 2 kg/m ² onto the surface of an open pile of coal powder with a floor area of 5000 m ² and a height of 10 m, and after one day, the viscosity (25°C) of the following composition was sprayed. ) A coating paint of 1000 centipoise and a thixoscopic index of 3.5 was sprayed at 3 kg/m ² . The coating film was almost dry and solidified after 6 hours. The film thickness was 0.2 mm.

50% by weight water emulsion of a copolymer of butyl acrylate and styrene with a monomer composition of 65:35 100 parts 1% by weight aqueous solution of methylcellulose 200 parts butyl cellosolve 2 parts 10% by weight aqueous solution of sodium hexametaphosphate 0.4 parts water 100 The deposits coated in this manner did not disintegrate even after 6 months had passed, and no scattering or runoff of coal powder or infiltration of rainwater was observed.

Comparative Example The surface of the same field deposit as in Example 1 was coated with a viscosity (25
℃) A coating paint of 100 centipoise and a thixoscopic index of 1 was sprayed at 3 kg/m ² . The coating film was almost dry and solidified after 8 hours. The film thickness was 7 mm (including the film thickness that penetrated into the inside of the deposit).

50% by weight water emulsion of a copolymer of butyl acrylate and styrene with a monomer composition of 65:35 100 parts 1% by weight aqueous solution of methylcellulose 100 parts butyl cellosolve 1 part 10% by weight aqueous solution of sodium hexametaphosphate 0.2 parts water 200 The deposit coated in this way had no waterproof properties and disintegrated after 0.5 months as the water content increased over time.

Example 2 The surface of an open pile of coal powder with a floor area of 4000 m ² and a height of 10 m was compacted and leveled by rolling, and then the viscosity (25
℃) 6000 centipoise, thixoscopic index 5.5 coating paint was sprayed at 3 kg/m ² . The coating film was almost dry and solidified after about 8 hours. The film thickness was 0.3 mm.

50% by weight latex of a copolymer of styrene and butadiene with a monomer composition of 50:50 100 parts cellosolve acetate 2 parts ethyl cellulose 2% by weight aqueous solution 150 parts water 150 parts The deposit thus coated will last for 6 months. It did not collapse even after the passage of time, and there was no evidence of any scattering or runoff of coal powder or intrusion of rainwater.

Claims (1)

[Claims] 1 Prepare a coating paint that contains a solute that becomes water-insoluble after drying, has a viscosity of more than 500 centipoise and less than 25,000 centipoise, and a thixotropic index in the range of 2 to 8, and apply this paint to the surface of open deposits. A method for coating open deposits, characterized in that the coating amount is applied in the range of 0.5 to 5 kg/ ^m2 .