JP2016050122A - Clay for ceramic product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, in the case of montmorillonite-containing clay, a crack is generated during dehydration.SOLUTION: Calcium chloride is added into clay containing montmorillonite to change contained montmorillonite into Ca type having low expansibility. Hereby, since contraction during dehydration is reduced as much as possible to prevent generation of a crack during dehydration, clay which has been disposed only on the ground that montmorillonite is contained can be utilized effectively, to thereby achieve cost reduction.SELECTED DRAWING: None

Description

  The present invention relates to a clay for ceramic products, which makes it possible to use clay containing montmorillonite for ceramic products such as tiles.

  The applicant of this application is a clay manufacturer that selects and blends multiple types of clay and mined clay from the Mikawa region (Toyota City, Anjo City, Seto City, etc.). In this region, the mining environment has deteriorated. Due to this, the clay shortage has become normal, so there is no choice but to make a plan only for the Tono area (Toki City, Tajimi City, Mizunami City, etc.), but it is not profitable from the viewpoint of transportation costs.

  Then, although the technique which manufactures a good quality clay by mixing a required mineral with the clay with inferior quality was developed (for example, refer patent document 1), this technique only supplements a deficient component to the last.

  In other neighboring areas, it was already known that clay (hereinafter referred to as Chita clay) was produced around the Chita peninsula, but if this Chita clay was used in ceramic products, cracks would occur during drying. Since it occurs, it is currently being discarded.

Thus, analysis of the components of Chita clay revealed that there was no difference from good-quality clay except that montmorillonite (Al ₂ O ₃ .4SiO ₂ .6H ₂ O) was included.
This montmorillonite is a layered clay mineral, and there are a Na type in which a large amount of Na ⁺ is adsorbed between crystal layers and a Ca type in which a large amount of Ca ²⁺ is adsorbed. In Japan, a Na type montmorillonite is common.

JP 2007-210873 A

  However, since Na-type montmorillonite may expand to 8 to 10 times the original volume, it is in an expanded state before drying, and as a result of large shrinkage due to drying, cracks are generated, so Na-type montmorillonite-containing clay There were problems that had to be solved, such as being unusable for ceramic products.

  The present invention is based on the above prior art, and in view of the problem that cracks occur when drying in a montmorillonite-containing clay, calcium chloride is added to the clay containing montmorillonite to make the contained montmorillonite a Ca type having low expansibility. Thus, the above problem is solved by reducing the shrinkage during drying as much as possible.

  In short, since calcium chloride is added to clay containing montmorillonite in the present invention, the contained montmorillonite becomes a Ca type with low expansibility, so that shrinkage during drying can be reduced and cracking during drying can be prevented, and thus ceramic industry The montmorillonite-containing clay, which is ineligible and discarded as a raw material, can be used as a raw material for ceramics, and its practical effect is significant.

The clay for ceramic products according to the present invention is mainly a raw material for roof tiles, and is obtained by adding calcium chloride (CaCl ₂ ) to clay containing montmorillonite, and when excessively added, calcium precipitates on the surface. In the case of Chita clay, the weight ratio of calcium chloride is 0.025 to 2, preferably 0.05 to 1, with respect to clay 100.

  The clay containing montmorillonite is a blend of one kind of clay or many kinds of clay, and at least one kind is montmorillonite-containing clay.

Montmorillonite is a layered clay mineral. There are Na type in which a large amount of Na ⁺ is adsorbed between crystal layers and Ca type in which a large amount of Ca ²⁺ is adsorbed. In Japan, Na type montmorillonite is commonly used. Since the type montmorillonite may expand to 8 to 10 times the original volume, it is considered to be cracked as a result of expansion in the state before drying and increase in shrinkage due to drying.

In this Na-type montmorillonite, Na ⁺ existing between layers can be exchanged with other ions and the like, and the ease thereof is as shown in the following inequality.

Li ⁺ <Na ⁺ <K ⁺ <Mg ²⁺ <Ca ²⁺ <Ba ²⁺ <Al ²⁺ <Fe ²⁺ <H ⁺

That is, since Ca ²⁺ is easier to replace than Na ⁺ , when calcium chloride (CaCl ₂ ) is added to montmorillonite-containing clay and mixed, Na ⁺ between layers in Na-type montmorillonite is replaced with Ca ^2+. Since it becomes Ca type montmorillonite having low expansibility, it is presumed that cracks are not generated.

  Note that the montmorillonite-containing clay is not limited to the above-mentioned Chita clay, and in short, the production area is not limited as long as it is a clay containing montmorillonite.

  If the amount of the calcium chloride added to the clay is too small, cracks will occur, and if it is too large, calcium will precipitate on the surface, so it is necessary to adjust the amount of montmorillonite.

Claims (1)

  Clay for ceramic products, characterized by adding calcium chloride to clay containing montmorillonite.