JPS6054349B2 - Surface treatment agent for storage of powder and granular materials piled up in the open - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment agent that forms a film on the surface of powder and granular material storage bodies that are exposed to the outside air and piled up in the open. This not only prevents heat generation, leakage, and collapse.

Various synthetic resins, inorganic substances, surfactants,
Wetting agents and mixtures thereof are conventionally used.

Examples of these include a method for preventing spontaneous combustion of coal by spraying a film forming agent on the coal during transport and deposition (Japanese Patent Application Laid-open No. 52-51401); A method of contacting a solution containing
11201) etc. Conventional surface treatment agents can be expected to have some degree of effectiveness, but they do not fully satisfy a variety of functions. For example, the surface treatment agent is eluted due to heavy rain or long-term rain. In addition, if the powder or granules are coal, the surface treatment agent containing inorganic substances may cause the inorganic substances attached to the coal to degrade the quality of the coke if the coal is carbonized as a raw material to produce coke or as fuel for a boiler. or damage the furnace wall. Furthermore, if the powder or granule is an ore, it will have an adverse effect on the sintering method, pellet manufacturing process, etc. in which the powder or granule is used in subsequent steps. The present invention has been proposed in view of the above, and is capable of stably retaining powder and granules for a long period of time, regardless of whether the powder or granules in the storage body piled up in the open are coal or ores. The present invention provides a surface treatment agent that does not cause any adverse effects even if it is used in a subsequent process.

The surface treatment agent of the present invention contains cement milk and a polymer resin emulsion solution as essential components, and actively utilizes the characteristics of cement and polymer resin.

Specifically, we focused on the fact that cement forms an extremely hard and stable film, but is brittle and easily disintegrates, and that polymer resins, especially acrylic resins and their copolymers, are flexible and form weather-resistant films. By synergistically utilizing the characteristics of the components, it is possible to provide an unprecedented surface treatment agent. The surface treatment agent of the present invention consists of cement milk in which fine cement powder is dispersed in water in an amount of 3% by weight or less, and resin emulsion in which a polymer resin is dispersed in water in an amount of 5 to 5% by weight. The component is a solution.

The cement of the cement milk used in the surface treatment agent of the present invention is
It is a heat-treated cement melted at a high temperature of 800° C. or higher, and when the powder or granules are ores, ordinary cement is preferable.

That is, free lime (f-C
aO) reacts with SiO2, which is a brick component, when coal is heated to 1100-1300°C, the temperature at which coal is carbonized, so when it is burned as fuel in a boiler with brick furnace walls as a subsequent process for piled coal, it It will invade the brick furnace wall. Furthermore, if f-CaO is present in the coal used as a raw material for coke, f-CaO is removed by red-hot coke fire extinguishing water spray after the coal is carbonized. , O and water react to form C
a(0H)2, which causes the coke lump to collapse and bubbles to exist, reducing the strength of the coke. Therefore, if the powder and granules in the storage body to be piled up in the open are coal, the cement should be melted with heat in advance to remove f-CaO from the cement components, or if f-CaO remains, it should be heat-treated cement, in which only a very small amount remains. is used.

In addition, alumina cement or early-strengthening cement with a low CaO content may be used for cement milk, and even Voltland cement with a high CaO content can be used if it is melted with heat in advance to reduce the f-CaO content. I'll come. The mixed amount of fine cement powder contained in the cement milk is 3% or less based on water. In other words, if the amount of fine cement powder exceeds 3% by volume relative to water, the fluidity of cement milk decreases, making it difficult to mechanically sprinkle it onto storage bodies piled up in the open, and even if it is possible to spray it, it will not be possible to store it. Since the particles do not flow sufficiently into the voids of the particles on the surface layer of the body, the particles on the surface layer of the storage body cannot be firmly fixed. On the other hand, when the above cement milk is directly sprinkled on the surface of the storage bodies piled up in the open, the fine powder particles on the surface layer of the storage bodies absorb the water content of the cement milk, and the cement concentration of the cement milk increases, causing the specific gravity to increase from 2 to 2. 3y/Clll), coal grains and ore grains move into the cement milk and function as aggregate.

Therefore, the cement concentration in cement milk has only an upper limit specified, but not a lower limit. However, from a practical and economic point of view, it is desirable that the amount of ruts be 1% or more based on water. j On the other hand, the polymer resin used in the resin emulsion solution, which is another component of the surface treatment agent of the present invention, is one that is weather resistant when a film is formed on the surface of the storage body,
Any material can be used as long as it is compatible with the powder on the surface of the storage body.

As such polymer resins, for example, vinyl acetate, vinyl chloride, acrylic, styrene, butadiene, butyl rubber, neoprene rubber, nitrile rubber, etc., and copolymers of these are most suitable. The above-mentioned polymer resins are dispersed in water together with an emulsifier such as a surfactant, or a solvent compatible with the resin to form an emulsion solution. This copolymer is an effective component because it has excellent weather resistance and flexibility.

When selecting a resin that forms a good film, which is the object of the present invention, the film forming temperature of the resin is a factor. That is, it is desirable that the minimum film formation temperature (hereinafter referred to as MF'T), which is the minimum temperature necessary for the resin to form a stable film, is at least close to room temperature (around 20°C). The present inventor has developed an emulsion of a copolymer of acrylic ester and methacrylic ester with styrene (resin content: 50%, 80%
0-2400CpS. ．． It has been found that the MFT range of PH8 to 9.5) is O to 23°C, which is convenient for forming a coating on coal or ores, which is the object of the present invention.

That is, acrylic esters (e.g. methyl acrylate,
One or more types selected from ethyl acrylate, propyl acrylate, etc.) and methacrylic esters (e.g., methyl methacrylate, ethyl methacrylate, propyl methacrylate, etc.) are emulsion polymerized, and this emulsion is It is necessary and minimum condition that MF'T is in the range of 0 to 23°C.

By copolymerizing styrene with the acrylic ester and methacrylic ester, a resin emulsion having several times the strength of the film can be obtained. or,
The range of resin composition that satisfies the above MFT is styrene 2
0-70%, acrylic ester and methacrylic ester 30-80%.

Further, by adding 1 to 1% by weight of wax emulsion, silicone, paraffin, etc. to the above emulsion, the water repellency of the resin coating can be significantly improved. In the acrylic styrenic resin emulsion obtained in this way, the emulsion particles coalesce to form a homogeneous continuous film with no gaps, and because the surface tension of the acrylic polymer is low, hydrophobic substances, i.e., low energy surfaces, are By thoroughly wetting it, the adhesion of coal to hydrophobic substances and cement coatings is excellent.

For these reasons, the acrylic styrene copolymer emulsion (MFTO-23SC) fully satisfies the desired performance in terms of water resistance, adhesiveness, strength of the formed film, etc.

The dispersion rate of the polymer resin in water varies depending on the type of polymer resin used or the type of emulsifier or solvent.

In addition, whether the resin emulsion solution is mixed with cement milk and sprinkled on the storage body, or the resin emulsion solution and cement milk are individually sprinkled on the storage body, the spraying liquid must be kept at a level that does not flow down the sloped surface of the storage body. Fluidity is required, and in order to satisfy such a wide variety, the polymer resin in the resin emulsion solution should be 10 to 50% by weight based on water.
is desirable and also economically effective. The above-mentioned cement milk and resin emulsion solution are because cement milk has a high pH value and is alkaline, so if it is mixed with a resin emulsion solution and stored for a long period of time, the emulsion of the resin emulsion solution becomes unstable and the resin becomes liberated. Therefore, it may not be possible to use it.

Therefore, during storage, cement milk and resin emulsion solution are separated, mixed immediately before use, and sprinkled on the surface of the storage body, and cement milk and resin emulsion solution are simultaneously sprayed from different nozzles of a spraying device. A method of spreading cement milk and a resin emulsion solution at predetermined time intervals can be proposed. Each of these spraying methods may cause some differences in the strength and weather resistance of the coating formed on the surface layer of the storage body, but which method is better depends on the condition of the storage body, cement milk, resin emulsion solution, and the method of spraying. It should be selected appropriately depending on the situation.
For example, when cement milk and resin emulsion solution are mixed immediately before spraying and sprinkled on the storage body, or when cement milk and resin emulsion solution are separated and sprayed at the same time, powder and granules are mixed with cement on the surface layer of the storage body. Since the resin component and the other components are bonded together, a flexible film is formed.

However, when cement milk and resin emulsion solution are sprinkled on the surface layer of the storage body at a predetermined time lag, the cement coating and the resin emulsion solution layer overlap.
It becomes a layer. In this case, if cracks occur in the cement coating,
The resin component penetrates into the cracked portion and closes it.
Therefore, it is desirable to spread cement milk and harden it to form a cement film, and then spread a resin emulsion solution to form a resin film. Regardless of the above-mentioned spreading method, the thickness of the coating to bring about the spreading effect on the storage body is 0.4 in the case of only cement.
~2.0wrm, 0.8~4 in case of polymer resin
．． Approximately 0wt is required.

The amount of spraying to obtain the above film thickness varies depending on the amount of cement contained in the cement milk and the amount of polymer resin contained in the resin emulsion solution, but it is 10 to 3% by weight.
cement milk with cement, and resin emulsion solution containing 10-5% polymer resin, respectively
．． The amount of spraying is about 5 to 2.0e/e. When cement milk and resin emulsion solution are mixed and sprayed, it is sufficient to spray the mixture at the same mixing ratio of about 3.0 to 4.0 e/bo. On the other hand, if the storage body is small-scale, the surface treatment agent of the present invention can be applied manually to the powder storage body using, for example, a portable sprayer.

However, if it is a large-scale storage that is impossible to do manually, it can be done automatically using a water truck that stores cement milk or resin emulsion solution inside. It can be distributed by any method. When the above-mentioned surface treatment agent of the present invention is applied to the surface layer of the storage body, it dries and hardens, resulting in a stable two-layer structure formed by the cement film and polymer resin film.
A layered film may be formed, or a film may be formed in which cement and powder particles are bonded together by a polymer resin.

This coating is extremely stable and airtight, so it will not leak out or be destroyed by wind or rain even for a long period of time, so it can reliably prevent the storage body from collapsing. In addition, the coating prevents outside air from flowing into the interior of the storage body, which not only prevents deterioration and spontaneous combustion when the powdery material in the storage body is coal;
There is no change in the water content in the storage body because rainwater does not infiltrate inside and the moisture contained inside does not evaporate. Furthermore, since the surface layer of the storage body is covered with a stable coating, coal dust and dust are not scattered by the wind. In addition, even if the powder and granules in the storage body are used in a subsequent process, they will not cause any damage regardless of the purpose of use, so they can be effectively used as storage bodies for coal and all kinds of ores.

Examples of the present invention are described below.

Example 1 Height: 3.0m. , base radius 4.27n1 surface area approximately 40d
A conical coal pile was formed, and various surface treatment agents were sprayed on the surface at a rate of 1.5 e/Rrl using a mortar sprayer, and after 10 days, water was sprinkled on the surface at a rate of 5 e/Min using a water sprinkler. At that time, we measured and measured the time it took for the coal pile to start flowing, and observed the state of collapse.

In addition, after the test, coal was collected from the center of the bottom of the coal pile, the moisture content was measured, and the increase rate was calculated by comparing it with the moisture content (9.5%) before the test.

Example 1 Acrylic resin (10% by weight) emulsion solution 0.75
e/i and alumina cement (15% by weight) milk 0.7
Spread 5e/bo at the same time.

Example 2 Equal amounts of acrylic styrene copolymer (1 weight %) emulsion solution and alumina cement (15 weight %) milk were mixed and spread at 1.5 f/wl.

Example 3 Acrylic resin (1 weight %) emulsion solution and early strength cement (15 weight %) milk were mixed in equal amounts, and then 1.
Spread with 5'/Rll.

Example 4 Alumina cement (15% by weight) milk at 0.75e/
dAfter 24 hours of spraying, apply acrylic resin (10% by weight).
) Spray emulsion solution at 0.75e/d.

Example 5 Early strength cement (15% by weight) milk at 0.75e/
After two intervals after spreading Wt, an emulsion solution of acrylic styrene copolymer (1% by weight) was sprayed at 0.75 e/i.

Example 6 Acrylic resin (1 weight%) emulsion solution at 0.75%
f/r! After 24B1 of spreading, alumina cement (15% by weight) milk was spread at 0.75e/d.

Comparative Example 1 - Sprinkle an acrylic resin (1% by weight) emulsion solution at a rate of 1.5'/I.

Comparative Example 2 An emulsion solution containing acrylic resin (1 weight %) and bulb fibers (2 weight %) was sprayed at 1.5 e/i.

Comparative Example 3 A water-soluble urethane (2.5% by weight) dispersion was sprayed at 1.5 e/d.

Comparative example 4 Boltland cement (15% by weight) milk 1.5e/
Distribute it.

Comparative Example 5 Alumina cement (15% by weight) was sprinkled with milk 1.5'/I.

Comparative Example 6 Early strength cement (15% by weight) Sprinkled with milk 1.5e/I.

Example 2 Same as Example 1, height 3.0 Tri, bottom radius 4.2
Tr1, Create a conical iron ore pile with a surface area of about 40 d,
A surface treatment agent was sprayed on the surface using a mortar sprayer, and after one week, water was sprayed on the surface at a rate of 5 d/min using a water sprinkler.The time until the ore pile started flowing out was measured and the state of collapse was measured. Observed.

After the test, mine was sampled from the center of the bottom of the ore pile, the moisture content was measured, and the increase rate was calculated by comparing it with the moisture content before the test. The results are shown in the table below. The surface treatment agents used were two types of Examples of the present invention and two types of Comparative Examples, and the spraying concentrations and spraying methods were as follows. Example 1 24 hours after spraying ordinary cement (15%) milk 1.0'/Rrl, acrylic resin (10%) solution 1.0e
Distribute /Rrl.

Example 2 Spraying 1.5 e/d of acrylic resin (15%) solution
After 4 hours, ordinary cement (15%) milk 1.5e/7
71' was distributed.

Comparison example 1 Sprinkle 2.0e/a of acrylic resin (10%) solution.

Comparative Example 2 Ordinary cement (15%) Milk 3.0e/I was sprinkled 1j0 The moisture content of the sample iron ore before the test was Hamasley. 4%, and Nibrasco 8.6%.

Claims (1)

[Scope of Claims] 1. Cement milk made by dispersing fine cement powder in an amount of 30% by weight or less in water, and an acrylic resin or a copolymer of an acrylic resin and another resin, and the film forming temperature is Polymer resin in the range of 0 to 23°C to water
A surface treatment agent for a storage body of powder and granular materials piled up in the open, comprising a resin emulsion in which 50% by weight of the resin is dispersed. 2. The surface treatment agent according to claim 1, wherein the cement is a fine powder obtained by heating, melting, cooling, solidifying, and finely pulverizing the cement, and the piled-up powder is coal powder.