JP2002053407A - Crushed material of used gypsum mold for ceramic mold for agrochemical and fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the effective utilization of used gypsum for a ceramic mold. SOLUTION: Crushed material of used gypsum mold for a ceramic mold is used as gypsum dihydrate for a carrier and a diluent of agrochemicals and fertilizers. Gypsum can be produced at a low cost and the used gypsum mold generated as an industrial waste can be recycled to solve the problem of the increasing difficulty in reserving a landfill site for the waste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0101]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gypsum-type pulverized product for a used ceramic material having a large holding amount per unit weight and a sustained release property, which is used for the purpose of increasing the amount of a carrier for agricultural chemicals and fertilizers, etc. It is about.

[0092]

2. Description of the Related Art Gypsum conventionally used as a carrier for agricultural chemicals and fertilizers includes gypsum dihydrate powder, hemihydrate gypsum powder and type III anhydrous gypsum.

The dihydrate gypsum powder is a gemstone or a chemical gypsum powder, but since both are crystalline, there is no impregnation of pesticides, fertilizers, etc. inside the crystal, and it is held only on the surface.

Therefore, in order to retain more of these with gypsum, it was necessary to grind the gypsum powder more finely.

In this case, since the holding place was only the crystal surface, the release was performed immediately after the application, and thus the sustained release property could not be controlled.

[0086]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems by increasing the holding amount of agrochemicals and fertilizers per unit weight, and further providing a sustained-release dihydrate. An object of the present invention is to provide a gypsum hardened product pulverized product at low cost.

007

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method of grinding a used gypsum mold for a ceramic material into about 1.5 mm or less using a crusher such as a jaw crusher or a hammer crusher. To use what you have done.

[0086] A normally-hydrated gypsum cured product can also be obtained by kneading hemihydrate gypsum with water, drying after curing, and then pulverizing. In this case, it is only necessary to hydrate and harden the gypsum hemihydrate. Rather, the powder is further dried and then pulverized, and these costs make it impossible to supply a ground dihydrate gypsum cured product at a practical price.

The particle size of the gypsum-type pulverized product for a used ceramic form material can be pulverized from an average particle size of about 1.5 mm to several tens of microns, but surplus water escapes inside the hardened gypsum by drying. There are no gaps, and there is no need for fine pulverization to increase the amount of pesticides held.

As a normal used dihydrated gypsum cured product, a gypsum mold for a ceramic material (usually called a late mold) used as a mold for use in a dish or a bowl is most suitable. Although it is used, it has been confirmed that it is of high purity and contains arsenic and heavy metals within the range of food additives.

In addition, as the used gypsum mold, a gypsum mold for a ceramic material, a case mold, a gypsum mold for industrial use or dental use can be used. However, these gypsums contain various additives and mixtures. In addition to that, the use of the present invention is problematic due to high collection costs due to non-concentrated areas used for industrial and dental purposes.

On the other hand, gypsum molds used for pottery porcelain materials are concentrated in pottery production areas such as Seto and Tono.
The significance of the present invention has become more important in recent years because it has become difficult to secure a landfill site as industrial waste.

The gypsum-type pulverized product for a used ceramic form material according to the present invention can be used not only as a carrier for agricultural chemicals and fertilizers, but also as a soil improving effect and a fertilizer effect of calcium sulfate.

[0141]

EXAMPLES Example 1 of a gypsum-type pulverized product for a used ceramic form material according to the present invention is a dish type with a water content of 60% as a first example, a cast type with a water content of 75% as a second example, and a natural Moroccan ore as a comparative example. Crush and 1.0-1.5mm on sieve
Prepare a mixture obtained by sieving in the above, and compare the retained amounts of pesticides and fertilizers by water absorption. Then, immerse 1 g of each sample in 20% saline for 5 minutes, and wash with 10 ml of distilled water. Then, the number of washings until the chlorine was no longer detected by silver nitrate was measured to compare the sustained release properties.

[0151]

As is clear from the above description, the crushed gypsum mold for used ceramic porcelain mold material according to the present invention has a large holding amount of pesticides per unit weight for pesticides and fertilizers. While having a sustained release property, not only can it be supplied inexpensively, but also it becomes possible to recycle industrial waste of used gypsum for a ceramic material.

Claims (1)

[Claims] 1. A gypsum-type pulverized product for used ceramic porcelain, which is used for agricultural chemicals and fertilizers, and has a large amount of agricultural chemicals per unit weight and a sustained release characteristic.