| abstract |
Slags, including the harmful-substance-containing slags, are not directly melted but are neutralized and processed into eco-resource materials, so that the slugs can be effectively utilized to purify and revive a large area of polluted water without any burden on the environment. Predetermined proportions of a non-recyclable harmful-substance-containing unused slag selected from by-product slags produced during the refining of a metal such as iron, copper, or aluminum from an ore, a porcelain clay for ceramics, and a mineral clay for ceramics, such as a quartz powder or an alumina powder, are kneaded to form a clay material with a suitable size. The clay material is burnt in a burning oven for ceramics at a predetermined temperature for a predetermined period of time so that a liquid glaze can sufficiently penetrate into the inner region of the clay material, thereby forming a biscuit clay material. A liquid glaze produced by kneading a powder made from a crushed special natural stone with a glaze for ceramics in a predetermined ratio followed by aging is applied, for example, to the biscuit clay material. As a result, a harmful-substance-containing unused slag is neutralized and used as an eco-resource filter medium. |