JP3006620B2 - Method for producing inorganic porous body - Google Patents

Description

The present invention relates to a method for producing an inorganic porous body.

The inorganic porous material according to the present invention is a soil improvement material in the agricultural field, horticultural cultivation soil, an agricultural chemical carrier, an adsorbent in the pet industry and livestock fields, a soil modifier for golf courses or tennis courts in sports, and a wastewater treatment field. It is useful as a filtering material and an aggregate in the construction field.

(B) Problems to be Solved by Conventional Techniques and Invention Conventionally, many inorganic porous bodies are known. For example, clays such as kaolinite and Kibushi clay are mined, diatomaceous earth is added to the clay, and the clay is fired to form a porous body. Also, diatomaceous earth was added to the mine tailings waste,
The porous body is made by firing (see Japanese Patent Publication No. 57-27864). In the production of these porous bodies, if the added amount of diatomaceous earth is increased, the porous body is likely to be formed, but the strength is reduced and the practicability is lacking. Conversely, if the added amount of diatomaceous earth is reduced, it becomes difficult to form a porous body, so that it is required to strictly control the added amount. On the other hand, the above calcination generally requires about 1100 to 1200 ° C., and the calcination cost is high, and there are many industrial problems.
In order to form a porous body, a foaming agent is added, and sawdust and an organic substance are also added.

(C) Means for Solving the Problems The present invention provides a method of mixing an appropriate amount of clay, diatomaceous earth, and dust dust as raw materials, granulating the granules in advance, and heating and calcining to obtain an inorganic porous body. Is what you do.

The clay in the present invention means an aggregate of fine hydrated silicate minerals. Clays preferably used in the present invention include by-products of producing silica sand from raw sand such as mountain sand. This by-product usually comes from raw sand 10-20%,
Most of it is buried as waste, where most of the raw sand is mined. Therefore, its effective use is not only economically advantageous but also extremely valuable in terms of preventing waste pollution.

On the other hand, diatomaceous earth is already used in many cases as a raw material for making it porous, but it is a scarce resource and a precious resource, and it is desirable to reduce the usage as much as possible. In the present invention, part or all of the diatomaceous earth is added in place of the dust collection dust, compared with a case where only diatomaceous earth is added, in addition to resource saving, excellent in quality can be obtained. It is based on knowledge.

As the dust collection dust, dust generated at the time of reclaiming and recovering the casting sand is preferably used. That is, after using a green casting mold (generally composed of sand, bentonite, starch, and coal powder), it is possible to use dust collected when the casting sand is regenerated by grinding and polishing the surface. In some cases,
Dust collected when regenerating an organic mold (generally composed of sand and furan resin) can be used. At this time, it is preferable to use the one to which bentonite is added as a dust collection dust source.

In the present invention, the mixing ratio of clay, diatomaceous earth, and dust dust in the raw material is important. Dust collected dust is added in an amount of 1 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 40 to 99 parts by weight of the clay. Diatomaceous earth, for clay 40-99 parts by weight,
0 to 30 parts, preferably 0 to 20 parts by weight is blended. The addition of diatomaceous earth is not always necessary, and there is no economic or technical advantage even if it is added above the upper limit.

The above-mentioned raw materials are granulated in advance in heating and firing. The shape is not particularly limited, granules, pellets,
It may be any one of a spherical shape and the like. The granulation method can be performed using a known method.

The calcination then suffices in the lower temperature range, e.g. Although firing for a short time in a high temperature region such as 1200 ° C. is conceivable, it has been found that the above low temperature region is preferable. This firing can be performed using a normal firing device.

The morphology of the porous body obtained by the present invention can be confirmed with an electron microscope.

 Next, the present invention will be described with reference to examples.

(D) Examples The clay used below is clay produced as a by-product from raw sand in Kyoto Prefecture. Dust collected is a by-product generated when sand is regenerated from a green mold. The chemical components of each raw material are as shown in Table 1.

Comparative Example 1 The effect of the sintering temperature on the properties of ordinary aggregate when the dust-collected dust of the present invention was not added was examined.

The bulk specific gravity was measured by molding a spherical product having a diameter of 10 mm and firing it at each temperature. Since the bulk specific gravity and the porosity of the porous body are proportional to each other, they are represented by the bulk specific gravity in this test. The breaking strength was measured by applying a load to the sample.

As is clear from the results in Table 1, the amount of diatomaceous earth added to make it porous only with clay and diatomaceous earth was 30% in view of the bulk specific gravity.
% And a firing temperature of 1200 ° C. in view of the breaking load strength.

Usually, industrially, the production of a porous body using clay and diatomaceous earth as raw materials is performed at a sintering temperature of 1200 to 1300 ° C., but the necessity of such high-temperature sintering is also proved from the above.

Example 1 A raw material consisting of clay, diatomaceous earth, and dust dust was granulated into granules, and the properties of the porous body and the effects of the firing temperature were examined.

From the results in Table 2, when the dust collection dust is added, an industrially excellent porous body can be easily obtained, and the one having high strength and small bulk specific gravity is manufactured at a firing temperature of 800 to 1000 ° C. We were able to.

As an industrial aggregate, when the bulk specific gravity is 1.3 or less and the breaking load strength is 70 kg / piece or more as the standard of the porous body, the effect of the dust collecting dust of the present invention is a great and excellent additive. .

This action is considered to be due to the fact that the residual bentonite contained in the dust collected increased the strength, and the residual coal powder and starch promoted the porosity.

Example 2 In order to know the effect of the dust collection dust of the present invention in more detail, properties when the amount of addition at a firing temperature of 900 ° C. was changed were examined.

From the results shown in Table 3, the strength of the aggregate is increased without increasing the bulk specific gravity as the added amount of the dust collection dust is increased, and the effect is extremely excellent.

Adds 20% dust collection without adding diatomaceous earth, 900
The properties of the porous aggregate can be satisfied at the firing temperature of ° C.

(E) Effects of the Invention As is clear from the above description, the porous body according to the present invention is a clay which is separated and generated when producing silica sand from raw sand such as mountain sand which has been conventionally treated as industrial waste. Diatomaceous earth, and dust collected during the recovery and recovery of foundry sand can be industrially obtained at low cost and with excellent properties, and the effect is great.

Also, when used for golf course greens as a use, it is said that the bentonite montmorillonite-based clay mineral contained in the dust collected during the recovery and recovery of foundry sand is useful for growing turf. The body is extremely effective.

Claims (3)

(57) [Claims] 1. 40 to 99 parts by weight of clay, 0 to 30 parts by weight of diatomaceous earth,
A method for producing an inorganic porous body, comprising granulating a raw material comprising 1 to 30 parts by weight of dust dust containing at least bentonite, and then heating and firing at 800 to 1000 ° C to obtain an inorganic porous body. 2. The method according to claim 1, wherein the raw material comprises 60 to 90 parts by weight of clay, 0 to 20 parts by weight of diatomaceous earth, and 10 to 20 parts by weight of dust collected. 3. The method according to claim 1, wherein the clay is clay produced during the production of silica sand from raw sand such as mountain sand.