| 摘要 |
PROBLEM TO BE SOLVED: To produce a sintered material in such a stable form that any harmful substance is hardly eluted from the material by mixing a powdery material which consists essentially of a waste material containing chromium and a phosphoric acid based compound, with a ceramic raw material containing a powdery zeolite and sintering the mixture at a specified temperature, to inhibit hexavalent chromium from being eluted from the resulting sintered material. SOLUTION: The powdery material which consists essentially of a waste material containing chromium such as chromium plating waste liquor and a phosphoric acid based compound such as aluminum phosphate are mixed with a ceramic raw material containing a powdery zeolite such as Oya tuff stone (produced in Japan), and the mixture is heated to >=1,000 deg.C or preferably, 1,100-1,170 deg.C for about 3 hr to produce the objective sintered material. Wherein by allowing the phosphoric acid based compound to act on the waste material containing chromium, hexavalent chromium can be inhibited from being formed and as the phosphoric acid based compound, not only aluminum phosphate but also sodium phosphite and calcium phosphite can be used, and also, by mixing such as powdery zeolite with the above powdery material containing chromium, the chromium can be inhibited from being eluted from the sintered material and the grain size of the powdery zeolite is about 0.5 mm. |
