JPS581070B2 - Manufacturing method of slag/magnesium carbonate plate material - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing inorganic board materials, and its purpose is to provide a method for manufacturing slag/magnesium carbonate board materials that are lightweight, have high strength, have excellent water repellency and workability, and can be manufactured in a short manufacturing time. There is a particular thing.

Conventionally, granulated blast furnace slag hardens by producing hydrates under alkali stimulation in the presence of water, and this property has been used to manufacture building materials.

However, although this building material has the strength as a wall material, its specific gravity is higher than 1, making it poor in workability and construction.Also, when various water repellents are added, the curing speed becomes very slow, or in some cases, It had drawbacks such as not curing at all, and furthermore, the effect of the water repellent agent was hardly exhibited.

On the other hand, magnesium carbonate, for example, can be made into a stable basic magnesium carbonate in a short time by blowing carbon dioxide gas into magnesium hydroxide slurry to make neutral magnesium carbonate and then curing with moist heat. This property is used to manufacture plate materials. has been done.

However, basic magnesium carbonate plates have the advantages of being lightweight, easy to work with, and can be highly effective if water repellents are added, but on the other hand, basic magnesium carbonate is a very bulky crystal, so it is not strong enough. It is unsuitable as a necessary wall material, and is only used for ceiling materials and insulation.

Therefore, in the present invention, as a result of various researches into a method for producing a building material plate having a synergistic effect by combining the advantages of the properties of granulated blast furnace slag and the properties of basic magnesium carbonate, and a water repellent, the present invention has been developed. The manufacturing method has been completed.

A method for manufacturing slag/magnesium carbonate-based plate material, which comprises forming a slurry containing a mixture mainly composed of granulated blast furnace slag and neutral magnesium carbonate, water, a water repellent, and fibers, and then curing with moist heat. Its most distinctive feature is that it hardens the granulated blast furnace slag by using the increase in pH value that occurs when neutral magnesium carbonate changes to basic magnesium carbonate as an alkaline stimulus, and also hardens the resulting calcium binder with low crystallinity. By filling the spaces between the crystals of basic magnesium carbonate, which has bulky crystals, and further acting as a binder, a lightweight and strong board material can be obtained.In addition, the water repellent acts on basic magnesium carbonate. The objective is to fully demonstrate the water-repellent effect of the board material.

Note that the method for producing an inorganic plate proposed in JP-A No. 54-64517 is to intertwine pre-formed bulky calcium silicate between large crystals of basic magnesium carbonate, but the present invention Granulated blast furnace slag and neutral magnesium carbonate are mixed in advance, and by a simultaneous chemical reaction, the spaces between the crystals of the magnesium carbonate, which is becoming large crystals, are filled with calcium binders with low crystallinity produced from the granulated blast furnace slag. Therefore, it is clear that the invention of JP-A-54-64517 and the present invention have different basic structures and also have different effects such as the strength and water absorption rate of the plate material obtained. .

Furthermore, in JP-A No. 54-120629, an inorganic hardened material containing cement, slag, and magnesium hydroxide is proposed in order to prevent the strength deterioration of the hardened ettringite material, which is a combination of calcium and aluminum compounds.
The slag and magnesium hydroxide in the cured body are added to prevent carbonation of the hardened ettringite body, and the basic structure is different from that of the plate material obtained by the method of the present invention. is the main raw material, So2- in gypsum, and Mg in magnesium hydroxide to be added.
2+ reacts to produce MgSo4, which causes an efflorescence phenomenon and impairs the appearance of the cured product, making it impractical.

The present invention will be explained in more detail below.

First, the granulated blast furnace slag used in the present invention is generally commercially available and is also known as a raw material for blast furnace cement.

Neutral magnesium carbonate is also commonly used, for example, produced by blowing carbon dioxide gas into magnesium hydroxide, and the water repellent added at the same time is added to impart water repellency to hardened board materials. Commonly used materials such as , paraffinic, rosin, and aliphatic can be used, but paraffinic and aliphatic are particularly preferred.

In addition to the above raw materials, various types of fibers (pulp, hemp, synthetic fibers, asbestos glass fibers, etc.) for reinforcing the cured board material, as well as release agents, pigments, and other additives are added as necessary.

The blending ratio of raw materials is preferably within the following range.

That is, the blending ratio of granulated blast furnace slag and neutral magnesium carbonate is 9:1 to 1:9 by weight, more preferably 9:1.
~3:7, and the reinforcing fiber is preferably about 20% by weight or less based on the total weight of the above-mentioned granulated blast furnace slag and neutral magnesium carbonate.
The appropriate amount of the water repellent is 1 to 20% by weight.

Next, water suitable for extrusion, casting, paper making, etc. is added to the above mixture to form a slurry, and after molding, it is further shaped by applying pressure at a low pressure of about 20 to 100 kg/cm2. Obtain planks.

Then, the plate material is heated to a temperature of 100°C or less, preferably 60°C or less.
Relative humidity is 60% or more in the range of 100℃, preferably 8
After being cured under moist heat for about 3 to 24 hours under conditions of 0°C or higher, the material is dried to obtain the desired cured board material.

In the present invention, the preferable range of temperature and humidity for moist heat curing of the board material after shaping is that the temperature is 60°C or less and the humidity is 60%.
In the following cases, neutral magnesium carbonate is difficult to change to basic magnesium carbonate and the pH value is difficult to increase.
The hardening of the granulated blast furnace slag is also very slow and the production time becomes very long.

On the other hand, when the temperature exceeds 100℃, the water boils, and the basic magnesium carbonate that has been formed is hydrolyzed and turns into the raw material magnesium hydroxide. At the same time, the reaction of the granulated blast furnace slag is too rapid, resulting in highly crystalline water. This is because the strength of the cured board material decreases significantly, and the board loses its strength as a building material.

The preferred blending ratio of granulated blast furnace slag and neutral magnesium carbonate is 9:1 to 3:7 by weight because it is necessary as a building material for walls and has appropriate bending strength due to the relationship between the strength and specific gravity of the hardened board material. 100Kg/cm2 or more, specific gravity is 0.
7 to 1.0 without adding much reinforcing fiber, and the cured board material obtained in this way is compared to conventional granulated blast furnace slag board material and magnesium carbonate board material. It is lightweight, has high strength, has excellent workability and water repellency, contains So2- in its raw materials, does not contain gypsum, etc., and therefore does not cause the efflorescence phenomenon, making it an ideal building board material.

Next, examples of the present invention will be shown.

Example 1 Six types of slurries having the following formulations (parts by weight) were molded using a paper machine and shaped at a pressure of 50 kg/cm2 to obtain a plate material with a thickness of 12 mm.

Next, these were cured under moist heat for 10 hours at a temperature of 80° C. and a humidity of 90%, and then dried at 120° C. for 1 hour to obtain a cured plate material.

The performance of the cured plate material with the above formulation was as shown in the table below.

As can be seen from the results in the table, the appropriate blending ratio of granulated blast furnace slag to neutral magnesium carbonate is in the range of granulated blast furnace slag:neutral magnesium carbonate -9:1 to 3:7 from the performance of the hardened plate material. I understand.

Example 2 50 parts by weight of granulated blast furnace slag, 50 parts by weight of neutral magnesium carbonate
parts by weight, 5 parts by weight of pulp, 5 parts by weight of asbestos, 5 parts by weight of water repellent, and 600 parts by weight of water were dispersed and mixed using a mixer to prepare a slurry.

The slurry was then shaped in the same manner as in Example 1 to obtain a plate material with a thickness of 12.

Next, these plates were cured for 10 hours under the following temperature and humidity conditions to obtain cured plates.

The performance of the cured plate material under each condition was as shown in the table below.

As can be seen from the table, the curing temperature and humidity conditions of the board greatly affect the performance of the cured board.

Claims (1)

[Claims] 1. A slag characterized by forming a slurry containing a mixture obtained mainly of granulated blast furnace slag and neutral magnesium carbonate, water, a water repellent, and fibers, and then curing with moist heat.
Method for producing magnesium carbonate-based plate material. 2. The method for producing a slag/magnesium carbonate-based plate material according to claim 1, wherein the composition ratio of the granulated blast furnace slag and neutral magnesium carbonate is in the range of 9:1 to 3:7 by weight. 3. The method for producing a slag/magnesium carbonate-based plate material according to claim 1 or 2, wherein the moist heat curing conditions are a temperature of 60 to 100° C. and a relative humidity of 60% or more.