JPH04106189A - Ceramic material for soil improvement - Google Patents

Abstract

PURPOSE:To provide the title material which has a uniform pore size and is improved in ventilation, water absorption, and fertilizer, water and oxygen retention by mixing coal ash with an organic binder and granulating the mixture, followed by firing. CONSTITUTION:The title material is prepared by mixing a coal ash having a particle size of 0.3-2mum with a solution or emulsion formed by dissolving or emulsifying 0.5-2% (in terms of solid content) of an organic binder (e.g. starch) in 10-15% of water based on the amount of the coal ash, granulating the mixture without applying pressure to obtain granules with a particle size 1-20mm, preferably 3-15mm, drying the granules ash required, heating the granules gradually to about 1,000 deg.C, firing the granules at the temperature for 2 hours, further firing them at about 1,300 deg.C for 2 hours, and allowing the resulting granules to cool to room temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic material that promotes plant growth when mixed with soil.

[Prior Art] Conventionally, representative soil improvement materials for horticulture include Hyugashi and granular pumice.

This pumice stone has good ventilation, drainage, and water supply properties, and when mixed with soil, it is known to improve these physical properties and have a positive effect on plant growth.

[Problem to be solved by the invention] Hyuga soil and granular pumice do improve soil and give good results for plant growth, but because they are natural materials, their effects vary widely, and their degree of porosity is not sufficient. However, the water absorption is not high at all, and it is desired that the amount of oxygen (air) retained is further improved.

Furthermore, since these products have not been subjected to any heat treatment, harmful bacteria and organic matter may also be mixed in, causing problems with plant growth.

The present invention was made with the aim of solving the above-mentioned problems, and it is a porous material with excellent uniformity, and the degree of porosity is large, so it has poor water absorption and oxygen retention properties. The purpose of the present invention is to provide a novel soil improvement ceramic material that has excellent ventilation, water supply and drainage properties.

[Means for Solving the Problems] In order to achieve the above objectives, as a result of repeated experiments in which powders of various Set raw materials were granulated and fired, it was found that fine powder of coal ash was combined with the adhesive strength of an organic binder. They discovered that if they were granulated using a chisel in the Snow Daruma method, molded, and fired at a high temperature, it could be made into a very suitable soil improvement material.

That is, the present invention uses fine powder of coal ash as a raw material, which is granulated without pressurization using only the adhesive force of an organic binder to form granules with a particle size of about 1 to 20 mm, preferably 3 to 15 layers. The gist of the present invention is a soil improving ceramic material characterized in that it is then fired at a high temperature to form a porous granular material.

Coal ash in the present invention is the ash that remains after burning coal, petroleum pitch, etc., and is called ply ash, whose main components are silicon oxide (SiOz) and aluminum oxide (A1103). However, the details of the components of this coal ash are shown in the table below.

Composition of coal ash Fine powder of coal ash (usually 0.3 to 2
(particle size) is used as a raw material, and an organic binder is first mixed with it and granulated.

This organic binder includes starch, methoxymethyl cellulose, carboxymethyl cellulose (CMC),
Sizing agents such as sodium alginate and tracanth gum, or polyacrylic acid ester, polyurethane, and polyvinyl acetate.

In addition, various synthetic resin emulsions, synthetic rubber or natural rubber latex, etc. can be used.

For example, an organic binder with a solid content ratio of 0.5 to 2% is added to the raw material coal ash in an amount of 10 to 1% based on the raw material coal ash.
It is dissolved or emulsified in 5% water, mixed with coal ash, and granulated using a granulator.

In this case, it is important not to apply pressure, and it is desirable to layer fine coal ash particles using only the adhesive force of the organic binder and granulate them into a nearly spherical shape, just like the Snow Daruma method. .

Note that if granulation is performed while applying pressure, the gaps between the fine particles of coal ash will become too dense, resulting in an inappropriate degree of porosity.

In this way, it is granulated and formed into a granular body with a grain size of 1 to 20 tw, but if the grain size is less than 11, the grain size is too low and the apparent specific gravity of this ceramic material becomes large. The granules tend to clump together, which is undesirable.
On the other hand, if the particle size exceeds 20 mm, the ceramic material becomes difficult to adapt to the soil and becomes an obstacle to the growth of plant roots, which has a negative impact on growth.

The most preferable particle size of this granule is 3 to 15 particles.

Next, the granulated material is fired at a high temperature.
It may be dried in advance and then stored in the firing oven, or it may be placed in the firing oven as it is without drying and dried during the temperature raising stage of firing.

This high-temperature firing method involves gradually raising the temperature to 1000
A preferred method is to bake at 1300°C for about 2 hours, then raise the temperature further to 1300°C for about 2 hours, and then let the temperature fall naturally, which takes about 24 hours from the initial temperature rise to the temperature drop. .

Note that there is almost no shrinkage of the granular material due to this firing.

The ceramic material obtained by firing in this way is a highly porous granular material that can be used for soil improvement, and when mixed with soil, the growth of plants is greatly promoted.

[Function] The present invention has the above-mentioned structure, and is made by granulating fine powder of coal ash, which is an inorganic raw material, to an appropriate particle size and firing it at a high temperature.The structure is that fine particles are pressed together. Since it has a laminated structure in which a large number of layers are connected, the gaps between them are large, resulting in a porous granular material with a high porosity.

Therefore, the ventilation is particularly excellent, and the pore size of the porous granules is almost uniform, which works synergistically with the high porosity to improve water absorption, water retention, and fertilizer retention. Although it holds a large amount of water and fertilizer, it also has a high ability to supply and drain water to the surrounding area. Due to these effects, the ceramic material of the present invention can be mixed with soil. When used properly, it has an extremely significant effect on plant growth.

In other words, when the soil becomes dry, the ceramic material of the present invention mixed in the soil replenishes the soil by discharging the water retained in the ceramic material, and conversely absorbs water when the soil has a high moisture content. This porous material has the effect of keeping the moisture contained in the soil at a constant level. Furthermore, this porous structure also contains a lot of air (oxygen), and its ventilation allows it to constantly maintain fresh air and provide the oxygen necessary for plant roots. supply it.

Additionally, since this ceramic material is treated at high temperatures, it is a sterile material, and the organic binder used for granulation is naturally burned away, making it a completely inorganic material whose effects continue semi-permanently. .

Although the ceramic material of the present invention has a heavy specific gravity, its apparent specific gravity is small and lightweight, making it easy to handle.

[Example] Coal ash with a composition consisting of the following main components and a particle size of 0
．． A fine powder of 5-2AL was used as the raw material.

Main components of coal ash Silicon 55.91% Aluminum oxide 29.42% Titanium oxide 2.18% Ferric oxide 2.34% Calcium oxide 1.09% (Other components are omitted as they are less than 1%) 5 kg of this coal ash was mixed with 650 g of a 7% aqueous solution of tracanth gum in a granulator without applying pressure, and the fine coal ash powder was formed into granules with a particle size of 3 to 15 tw. .

The granules were placed in a firing oven and heated while drying, and after about 6 hours, the temperature was increased to 1000''C!, and firing was continued at this temperature for 2 hours, and the temperature was further increased to 1300°C over about 2 hours.

After firing at 1300° C. for 2 hours, the heating was gradually weakened and stopped, and after being left for about 6 hours, it was taken out of the kiln.

As a result, the granules were fired with almost no shrinkage.

When the various physical properties of the ceramic material thus obtained were measured, the results shown in the table below were obtained.

For comparison, the physical properties measured for the conventional product Hyuga soil are also listed.

(However, the hardness is the old Mohs hardness.) From this table, it can be seen that the ceramic material of the present invention has extremely superior porosity compared to conventional Hyuga soil, has excellent ventilation and water absorption, and has excellent water retention and retention. It is also highly fertile, and its porosity is uniform, so it is recognized to exert water supply and drainage functions depending on the surrounding environment.

In addition, when compared with hard clay (ion clay), which is considered to be close to the ceramic material of the present invention in terms of chemical composition,
This hard clay has an apparent specific gravity of 2.53 to 2.55, which is incomparably heavier than the 0.6 to 0.7 of the ceramic material of the present invention, and this hard clay is a material that is hardly porous. One thing has been recognized.

The ceramic material with a particle size of 3 to 15 mm obtained in this example was coated with 3 to 5 layers, 6 to 10 layers, and 3 layers of 11 to 15 mm.
When we sorted the particles into different types, mixed them with soil, and grew plants suited to their particle sizes, we obtained extremely superior plant growth in all cases compared to just soil or conventional soil amendments. It is.

Regarding this plant experiment, it is difficult to provide detailed data due to individual differences in the plants themselves, various conditions such as fertilizer, water, sunlight, temperature, etc., but it is clear from the presence or absence of the use of the ceramic material of the present invention. It is clear that a significant difference has occurred.

[Effects of the Invention] The effects of the present invention are described in detail in Section J, but can be briefly summarized as follows.

(a) Because coal ash, which is a fine powder, is granulated to an appropriate size and fired without being pressurized, it is a ceramic material with an extremely high degree of porosity and a nearly uniform pore size. It has become.

(b) Therefore, ventilation, water absorption, fertilizer retention, water retention, I
It has an excellent ability to retain 'ff elements, and also has water supply and drainage effects that suit the environment.

(C) Because it has such physical properties, it has an extremely high effect on plant growth when mixed with soil, and since it is artificial, there is no variation in this effect.

(d) Because it is baked at high temperatures, it does not contain harmful bacteria or organic substances, so it has no adverse effect on plants, and since it is inorganic, it can be used semi-permanently.

As described above, the present invention exhibits various excellent effects and exhibits extremely high usefulness in industrial fields such as agriculture and horticulture.

Claims (1)

[Claims] 1. Using fine powder of coal ash as a raw material, it is granulated using only the adhesive force of an organic binder without applying pressure, and the particle size is about 1 to 20 mm, preferably 3 to 15 mm.
1. A soil improvement ceramic material characterized in that it is formed into a granular material having a diameter of 1.5 m, and then fired at a high temperature to obtain a porous granular material.