JPH089497B2 - Manufacturing method of inorganic products - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an inorganic product, and more particularly to a method for producing an inorganic product for effectively utilizing fly ash which is an industrial waste.

[Conventional technology]

Conventionally, it has been widely practiced to mold products such as building materials with a cement mixture.

A silica source is indispensable for improving the strength of this cement product, and silica sand or the like has been generally used as the silica source.

By the way, SiO ₂ is also contained in fly ash, which is an industrial waste.
Since it is contained in a large amount, it has been known to use it as a silica source, and various methods for producing inorganic products using these fly ash have been proposed in combination with effective use of industrial waste.

[Problems of conventional technology]

By the way, the fly ash has a difference in ignition loss depending on the conditions of the production furnace, and if this ignition loss is too large, there is a drawback that the strength development is low.

Therefore, for products that require strength such as building materials, fly ash as a silica source is only applicable to products with a loss on ignition of 5% or less, and those with a loss on ignition greater than this, for example, a loss on ignition of 5 If more than%, it was unsuitable as a raw material, and it was only landfilled.

[Problems to be Solved by the Invention]

In view of the above, the present invention aims to provide an effective use of fly ash having a high ignition loss, which was conventionally left to be simply discarded, and to provide a method for producing an inorganic product having no problem in strength. It is a thing.

[Technology that has solved the problem]

That is, in the method for producing an inorganic product of the present invention, in a cement mixture that uses JIS-compliant quality fly ash (loss on ignition of 5% or less) as a silica source, a part of the JIS-compliant quality fly ash is used as JIS-compliant quality. JIS replaced by fly ash with ignition loss of 5% or more other than
Characterized by adding silica fume in an amount corresponding to 1/5 to 1/4 of fly ash of the relevant quality, mixing this as a silica source with cement and other additive compounds, and molding according to a conventional method Is.

[Action]

The cement composition presupposed in the present invention is a composition using fly ash as a silica source. For example, the cement content is 40% by weight of fly ash having an ignition loss of 5% or less.
40% by weight, and a total of 100% by weight by adding PA reinforcing fibers and fine aggregate as other raw materials.

In the present invention, a part of the fly ash having an ignition loss of 5% or less is replaced with a fly ash having an ignition loss of 5% or more other than JIS-compliant quality.

This substitution deteriorates the quality of the silica source and also the bond strength of the cement matrix, but this reduction is caused by the substitution amount.
Supplement by adding silica fume in an amount corresponding to 1/5 to 1/4.

The reason why the addition amount of silica fume is limited to 1/5 to 1/4 of the substitution amount is that if the amount is less than 1/5, the strength cannot be improved, and if the amount is more than 1/4, the strength cannot be improved for the amount added. This is because it is uneconomical because you cannot expect it.

Despite the addition of fly ash, which has a large ignition loss, the addition of silica fume described above sufficiently enhances the bonding strength of the cement matrix and makes it possible to mold an inorganic product having no practical problems.

In the present invention, it is desirable that the molded article be cured at a high temperature and a high pressure by an autoclave in order to achieve strength development.

〔Example〕

 Next, an embodiment of the present invention will be described.

The basic composition is 40% by weight of fly ash of JIS, 42% by weight of cement, 8% by weight of pulp fiber as reinforcing fiber, and 10% by weight of pearlite as lightweight aggregate. As shown in Table 1, the parts are replaced with fly ash of 20% or more of ignition loss other than JIS relevant quality, and at the same time, silica fume is added to 1 / 4.5 of the replacement amount, and thereafter, the thickness is 20 mm according to a conventional method. Vertical and horizontal
A 300 mm test plate was formed and autoclaved at 150 ° C.

When the bending strength of each test piece was measured, the results shown in the lower column of Table 1 were obtained.

As is clear from Table 1, the examples in which silica fume was added were found to have strength substantially equivalent to the basic composition.

[Effect] As is clear from the above, the conventional method was to dispose of the product.
Even fly ash that does not conform to JIS can be effectively used as a silica source for cement products without reducing the product strength.

Claims (1)

[Claims] 1. In a cement formulation that uses JIS-compliant fly ash (less than 5% ignition loss) as a silica source, a part of the JIS-compliant fly ash is ignited by non-JIS ignition loss of 5%. Replaced with the above fly ash, and 1/5 of the JIS-compliant quality fly ash that has been replaced
A method for producing an inorganic product, which comprises adding silica fume in an amount corresponding to 1/4, mixing this as a silica source with cement and other additive compounds, and molding the mixture according to a conventional method.