JPH0139711B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an agent for suppressing an increase in the moisture content of open deposits such as open coal and ore. [Prior Art] Drained coal, ore, etc. are generally conveyed by a conveyor and stored in piles in an outdoor storage yard using a stacker or the like. Rainwater infiltrates these open deposits due to rainfall, and their moisture content increases. Conventionally, these open deposits were
Measures have been taken to prevent scattering, heat generation, deterioration, etc., but no serious measures have yet been taken to prevent rainwater from penetrating. [Problem to be solved by the invention] The increase in moisture content due to rainwater infiltration of open piles is
consumes extra energy for water evaporation,
Not only does this result in a large economic loss, but in the case of coking coal, it also has various negative effects on the coke manufacturing process. Therefore, the increase in moisture content due to rainwater is 1%.
Just suppressing it can bring great benefits. [Means for Solving the Problems] This invention is intended to solve the above problems, and by using a specific acrylic resin aqueous emulsion as an active ingredient, it is possible to efficiently suppress the increase in water content. The present invention provides an agent for suppressing the increase in moisture content of open deposits. This invention relates to a moisture content increase suppressant that is sprayed and coated on open deposits, which is a homopolymer of monomers selected from acrylic acid, methacrylic acid, and esters thereof, or a copolymer of two or more monomers. Union,
Or, the active ingredient is an acrylic resin aqueous emulsion that is composed of a copolymer with other monomers, has film-forming properties at room temperature, and forms a water-insoluble film with a water-soluble content of 1% by weight or less. It is an agent that suppresses the increase in moisture content of open deposits. The open deposits to be treated in the present invention are powdery, granular or lumpy deposits of coal, ore, etc. piled outdoors, and the location of the deposit,
The deposition method and the shape of the pile pile are not limited. The acrylic resin used in the present invention is
It is a homopolymer or a copolymer of two or more acrylic monomers, or a copolymer of one or more acrylic monomers and one or more other monomers. Acrylic monomers are monomers made of acrylic acid, methacrylic acid, or derivatives thereof, such as acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, methyl methacrylate, and methacrylate. Methacrylic acid esters such as ethyl acid, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, acrylic acid or methacrylic acid, or its hydroxyethyl ester or hydroxypropyl ester, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylamino Quaternary compound of ethyl acrylate, quaternary compound of dimethylaminoethyl methacrylate, 2-hydroxy-3
-Methacryloxypropylmethylammonium chloride, etc. can be exemplified. Examples of monomers copolymerizable with acrylic monomers include vinyl acetate, vinyl propionate, vinyl versatate,
Vinyl stearate, maleate, fumarate, ethylene, styrene,
Examples include α-styrene, vinyl chloride, and vinylidene chloride. The content of these monomers is preferably 40 mol% or less based on the acrylic monomer. The aqueous acrylic resin emulsion used in the present invention is an aqueous emulsion containing one or more of the above acrylic resins, and is obtained by emulsion polymerization of the above monomers in the presence of a surfactant.
If the amount of surfactant is less than 1% by weight, the effect of suppressing the increase in water content is large, but the emulsion becomes unstable and aggregates are likely to occur. It is preferable to add the following amount. The surfactant used during polymerization of the aqueous acrylic resin emulsion may be any nonionic, anionic or cationic surfactant. Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, and polyoxyethylene fatty acid ester. Examples of the anionic surfactant include alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylsulfosuccinates, polyoxyethylene alkylsulfates, fatty acid salts, and the like. Examples of cationic surfactants include primary amine salts, secondary amine salts, tertiary amine salts, and quaternary ammonium salts having aliphatic hydrocarbon groups. preferable. Examples of the cationic surfactant of this quaternary ammonium salt include lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, and stearyltrimethylammonium chloride. The method for producing the aqueous acrylic resin emulsion of the present invention may be any known emulsion production method. For example, an acrylic monomer is stirred and dispersed in water together with a surfactant, heated while blowing nitrogen gas, and a catalyst such as benzoyl peroxide, persulfate, hydrogen peroxide, or these oxidizing agents and sodium thiosulfate are mixed. An aqueous emulsion can be produced by carrying out emulsion polymerization by adding a redox catalyst in combination with a ring agent such as sodium bisulfite or the like. It is preferable to add a polymerization accelerator such as copper sulfate in addition to the catalyst because the resin particles of the resulting emulsion become smaller and the emulsion stability improves. In order to enhance emulsion stability during or after emulsion polymerization, protective colloids such as polyvinyl alcohol, hydroxyethyl cellulose, and carboxymethyl cellulose can be used. Surfactants and protective colloids can be used singly or in combination of two or more, and can be added during or after polymerization or emulsification. The aqueous acrylic resin emulsion that can be used in the present invention has film-forming properties at room temperature and forms a water-insoluble film with a water-soluble content of 1% by weight or less. Here, film-forming property means that when the emulsion is applied onto a clean slide glass plate, a continuous film with uniform dryness is formed at room temperature.
Also, water soluble content of 1% by weight or less means that the dry film is 30% by weight or less.
This means that the water soluble content when immersed in distilled water at ℃ for 24 hours is 1% by weight or less of the dry film. In order to reduce the water-soluble content of the dry film of the aqueous acrylic resin emulsion to 1% by weight or less, hydrophilic monomers that increase the water-soluble content, such as acrylic acid,
It is preferable that methacrylic acid, etc. be 8% by weight or less based on the total monomers. When surfactants and protective colloids are used in large amounts, the water-soluble content of the film increases, so it is preferable to limit the amount added within the above range. In order to enhance the film-forming properties of the aqueous acrylic resin emulsion and form a continuous film at room temperature, a plasticizer or a film-forming aid may be added. Plasticizers and film-forming aids also have the effect of imparting flexibility and adhesiveness to the film. Examples of these include butyl cellosolve,
Examples include butyl cellosolve acetate, butyl carbitol, carbitol acetate, hexylene glycol, dibutyl phthalate, dioctyl phthalate, etc., but water-soluble ones increase the water-soluble content of the film, so hydrophobic ones are preferred. The moisture content increase inhibitor of open deposits of the present invention is
The above-mentioned aqueous acrylic resin emulsion is used as an active ingredient, and conventionally known fillers, pigments, etc. can also be added thereto. [Function] The moisture content increase inhibitor of open deposits of the present invention is
It is usually used at a resin concentration of 2.5 to 10% by weight, and is sprayed directly onto open piles to cover them and prevent an increase in the water content of the open piles. There are the following methods of dispersion. 25 to 200 g, preferably 50 to 100 g of resin is applied to the open heap pile surface ^{per square} meter of pile surface. At that time, a sprayer can be used to uniformly spray the entire surface of the heap. The chemical may be sprayed only once, or may be sprayed multiple times. When a pile is formed, it is spread on the conveyor belt to the surface layer of the pile, which is being transported. When the pile is formed, all the sediment being transported is sprayed on a conveyor belt. After forming a heap by spraying as described in or above, the material is further sprayed on the surface layer in the same manner. The surface of the pile is pressure-formed using a pressure roller or a pressure plate, and the average density of the surface layer at a depth of about 40 cm from the surface (the average density sampled from each layer that divides the surface into multiple equal parts) )
After increasing the amount by 5 to 30%, spray on the surface in the same way. Among the above methods, the following methods are particularly preferred. To explain the details of this method, first, drained coal and the like are conveyed by a belt conveyor and piled up in a yard by a stacker. The pile piled up from the stacker is unstable at first, but if left for a day or two, it will tighten and become stable under its own weight. If there is a lack of moisture, the pressurizing effect will be reduced, so you can increase the moisture content to 5-10% by sprinkling water. Next, the surface of the stabilized pile is formed by pressure using a pressure roller, a pressure plate, or the like. in this case,
A pressure roller, etc. is hoisted up by a crane truck, etc., and rolled up and down along the slope of the pile.
Can be pressure molded. The larger the pressing force of the pressure roller, etc., the more effective it is, but if it is 0.5t/m ² or more, the effect will be visible. Rolling is performed about 1 to 10 times to increase the average density of the surface layer by 5 to 30% and to form a smooth surface. After molding, a moisture content increase inhibitor is sprayed onto the surface layer in the manner described above. When the moisture content increase inhibitor is sprayed on open piles as described above and left to dry, a resin film is formed, and the resin film and coal are strongly bonded to the surface of the pile. It strengthens the structure and makes the sediment on the surface of the pile hydrophobic. Therefore, internal infiltration of rainwater can be prevented, and an increase in the moisture content of the sediment can be suppressed. Also, because the film is strong, it can prevent piles from collapsing due to heavy rainfall. Since the present invention's inhibitor for moisture content increase in open deposits is an aqueous emulsion, there is no toxicity or fire hazard caused by solvents, and it is easy to dilute with water and clean equipment, and can be easily sprayed over a wide area. Can be applied. [Effects of the Invention] According to the present invention, since a specific acrylic resin aqueous emulsion is used as an active ingredient, it can be easily and safely sprayed onto open piles by simple operations to form a hydrophobic film. , This makes it possible to efficiently suppress an increase in the moisture content of the sediment. [Example] Next, an example of the present invention will be described. In each example, % indicates weight %. Example 1 Using polyoxyethylene alkyl ether as a surfactant, the monomers shown in Table 1 were subjected to emulsion polymerization, and the film-forming properties of the various resin aqueous emulsions obtained, the water-soluble content, and these agents were evaluated. The effect of suppressing the increase in moisture content when sprayed on the coal surface was tested. Film-forming properties and water-soluble content tests were conducted in accordance with JISK6828 (vinyl acetate resin emulsion test method) using the following method. Film-forming property: Spread the sample over a clean glass slide plate, dry it at room temperature, and make a uniform film with a thickness of 0.1 to 0.3 mm. Observe with the naked eye whether the dried product is a uniform continuous film. . Water soluble content test: The film prepared in the film-forming section above was immersed on a slide glass plate of known mass in distilled water adjusted to 30°C ± 0.5°C for 24 hours, taken out and air-dried.
Weigh the mass after leaving it in a desiccator for 24 hours.
Calculate the water soluble content using the following formula. Water soluble content (%) = Mass before water immersion (g) - Mass after water immersion (g) / Mass before water immersion (g) - Mass of slide glass (g) x 100 The effect of suppressing the increase in water content is This was confirmed using the following method. That is, 10 tons of cellulose charcoal with a total moisture content of 8.0% were piled up in a conical shape, various resin aqueous emulsions were adjusted to a resin concentration of 5%, and then this was evenly spread at a ratio of 2/m ² and left in the natural environment for 3 days. Dry. Next, this was exposed to artificial rain with a rainfall intensity of 30 mm/hr for 30 minutes, and then a sample of the coal 10 cm below the surface of the pile of coal was sampled to measure the total moisture content. The results are shown in Table 1. Table 1 shows that the acrylic resin aqueous emulsion, which has film-forming properties at room temperature and forms a water-insoluble film with a water-soluble content of 1% by weight or less, has an excellent effect of suppressing increases in the moisture content of coal. Recognize.

【table】

[Table] Example 2 As in Example 1, 10 tons of cellulose charcoal with a total moisture content of 8.5% were piled up in a conical shape, and then the surface layer approximately 40 cm from the surface was pressurized with a pressure roll. Thereafter, the aqueous resin emulsions A, B, E, and F used in Example 1 were adjusted to a resin concentration of 5%, and then uniformly spread at a density of 2/m ² and air-dried for 3 days. Next, after exposing the coal to artificial rain with a rainfall intensity of 30 mm/hr for 30 minutes, the coal was sampled 10 cm below the surface of the pile of coal, and the total moisture content was measured. As a comparative example, a test was also conducted in the same manner as in Example 1 in which no pressure was applied to the surface layer. The results are shown in Table 2.

[Table] From Table 2, it can be seen that the acrylic resin aqueous emulsion that forms a water-insoluble film with a water-soluble content of 1% by weight or less exhibits even better effects when surface layer pressure is used in combination.

Claims (1)

[Scope of Claims] 1. A moisture content increase inhibitor to be sprayed and coated on open deposits, which is a homopolymer of monomers selected from acrylic acid, methacrylic acid, and esters thereof, or two or more thereof. or a copolymer with other monomers, has film-forming properties at room temperature, and forms a water-insoluble film with a water-soluble content of 1% by weight or less. An agent for suppressing increases in moisture content of open deposits, characterized by containing an emulsion as an active ingredient. 2 Acrylic resin is 8% by weight based on the total monomers
The inhibitor for increasing the water content of open deposits according to claim 1, which contains the following hydrophilic monomers. 3. Water content of open deposits according to claim 1 or 2, wherein the acrylic resin aqueous emulsion contains more than 1% by weight and less than 10% by weight of a surfactant based on the total monomers. Rise inhibitor. 4. The inhibitor for increasing the moisture content of open deposits according to any one of claims 1 to 3, wherein the aqueous acrylic resin emulsion is emulsion polymerized using a surfactant.