JPH05292832A - Soil for horticulture - Google Patents

Abstract

PURPOSE:To provide the lightweight horticultural soil excellent in the water permeability, water retainability and gas permeability, not strong in alkalinity and suitable for the growth of plants. CONSTITUTION:Porous calcium silicate hydrate (hereinafter referred to as ALC) hydrothermally synthesized in the presence of a foaming agent, especially ALC recovered from building sites, etc., is carbonated in the presence of water and subsequently used as the soil for horticulture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to horticultural soil, particularly potting soil, garden tree soil, hydroponic soil and nursery soil.

[0002]

2. Description of the Related Art Natural soil has been mainly used for horticultural soil. On the other hand, recently, artificial ones such as slag produced as a by-product in a steel mill, which has a characteristic that it has a small apparent specific gravity and is easy to transport and handle, have been used. However, since slag has a strong alkalinity and is not suitable for growing plants, it also has a drawback that expensive peat moss or the like must be mixed and used.

It has also been proposed to use a hydrothermally synthesized calcium silicate porous body which is lightweight and has excellent water permeability, water retention and air permeability as artificial soil. However, the hydrothermally synthesized calcium silicate porous body is highly alkaline and is not suitable for plant growth as described later.

[0004]

As can be seen from the above, artificial horticultural soils such as slag and hydrothermally synthesized calcium silicate porous material are lightweight and easy to carry and handle. It is understood that an ideal horticultural soil is one that retains the characteristics of excellent water permeability, water retention, and breathability, but has improved the drawback of being highly alkaline and unsuitable for plant growth. It

That is, it is an object of the present invention to provide a horticultural soil which is light in weight, excellent in water permeability, water retention and air permeability, and not strongly alkaline.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a porous calcium silicate hydrate hydrothermally synthesized by adding a foaming agent (hereinafter, a porous calcium silicate hydrate hydrothermally synthesized by adding a foaming agent. Is abbreviated as ALC.), Which is carbonized in the presence of water. ALC used in the present invention
Is a porous calcium silicate hydrate obtained by using a siliceous raw material and a calcareous raw material as main raw materials, adding a foaming agent to the raw materials, preliminarily curing them, and then performing hydrothermal synthesis in an autoclave. Many calcium silicate hydrates are known, but calcium silicate hydrates suitable for the present invention are zonotolite, tobermorite, gyrolite, foshajite, hirebrandite, etc. Is. These calcium silicate hydrates do not have to be used alone, and may be used as a mixture of two or more kinds. In addition, these calcium silicate hydrates are not completely pure, and include CSH gel and unreacted siliceous raw materials.

The ALC used in the present invention is manufactured in large quantities as a building material and a heat insulating agent, and can be easily obtained. For example, some defective products (such as fine cracks) generated in the ALC manufacturing plant are included. A) that occurs at construction sites of buildings and houses and construction sites of heat insulating materials
LC offcuts (cuts) can be used. A granular ALC having a uniform particle size can be obtained by coarsely crushing the scraps of ALC and defective products and appropriately sieving. The particle size is not particularly limited for use in the present invention, but the apparent specific gravity of ALC having a particle size of 0.6 to 15 mm is about 0.2 to 0.7 (depending on the type and particle size of ALC). It is lightweight, has excellent breathability, water retention, water permeability, and the like, and also has appropriate strength and is extremely favorable in physical properties as a gardening soil, which is preferable. However, ALC is originally strongly alkaline (5g of granular ALC
When the pH is measured by putting it in water, the pH is 10.1 to 10.
It is 9. ) It is necessary to weaken the alkalinity.

As a method for weakening the alkalinity of ALC, it is common to neutralize with an acid. As a method for neutralizing while maintaining good physical properties as a horticultural soil, the carbonation reaction is promoted by introducing granular ALC into water and blowing carbon dioxide gas. The carbonation rate can be appropriately set depending on the temperature during the reaction, the pressure of gas blowing, and the like, but the carbonation reaction is fast under the condition that 50 to 120 parts by weight of water is present relative to 100 parts by weight of the granular ALC, which is preferable. .

[0009]

The present invention will be described in more detail with reference to the following examples. The ALC mill ends collected from the building construction site were soaked in a crusher, the inner reinforcing bars were pulled out, and then coarsely crushed by a hammer mill. The coarsely pulverized product was sieved and then sufficiently dried at 110 ° C. to obtain granular ALC having a particle size of 1 to 3 mm. It was confirmed by X-ray diffraction and fluorescent X-ray analysis that the granular ALC was calcium silicate containing tobermorite as a main component and the Ca / Si ratio was 0.58. The apparent specific gravity was 0.50, and when 5 g of the granular ALC was placed in 500 g of water and the pH was measured, the pH was 10.56.

1 kg of the above-mentioned granular ALC having a particle size of 1 to 3 mm
Water (1 kg) was evenly sprayed on it and then put in an autoclave. After deaerating the inside of the autoclave, carbon dioxide gas was injected under pressure until the gauge pressure reached 1.2 kg / cm, and thereafter this pressure was maintained for 3 days. Carbonated granular AL thus obtained
C was analyzed by an X-ray diffractometer, and it was confirmed that the tobermorite crystal disappeared completely and that calcite was generated. The pH was measured as described above and found to be 9.05.

Five petri dishes having a diameter of 10 cm were prepared. Carbonated granular ALC was put into each petri dish up to the edge of the petri dish, and an appropriate amount of water was put into the petri dish to make the particulate ALC wet. Spread 50 seeds of Komatsuna on each dish,
It was placed in a room at room temperature of 20 ° C. for 10 days and the germination status and the subsequent growth status were observed. During this time, an appropriate amount of water was put in each petri dish so that the same wet state was always maintained. The germination rate after 3 days was 92% on average in each petri dish, but on the 7th day, it grew to an average of about 3.1 cm and the leaves continued to grow without wilting.

[0012]

Comparative Example A test similar to that of the example was carried out using granular ALC which was not carbonated. Germination rate after 3 days is 90 on average
%, On the 7th day, it grew to an average of 12.5 cm, but thereafter the leaf tips became rounded and shrank, and the growth almost stopped.

[0013]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a horticultural soil suitable for growing plants, which is light in weight and excellent in water permeability, water retention and air permeability and is not strongly alkaline, from an inexpensive raw material.

Claims (1)

[Claims] 1. A horticultural soil obtained by carbonating porous calcium silicate hydrate hydrothermally synthesized by adding a foaming agent in the presence of water.