| 摘要 |
<p>PROBLEM TO BE SOLVED: To make the harmless of dross in a simple method by adding and heating a prescribed quantity of water into the dross. SOLUTION: The adding quantity of water is desirable to about 1/3-3 times to the dross. In the case of being less than the range, a hydrolytic reaction is made to insufficient. In the case of being too mush to the range, a solid-liquid separating equipment is necessary and a problem of drainage treatment, etc., is developed. Heat and stirring temp. after this treatment, is desirable at 60-100 deg.C for uniformly promoting the reaction. In the case of being more than the range, heat loss caused by vaporization of the water is large and therefore, this is uneconomical. In the dross becoming paste-state after water-treatment, ammonia produced by the hydrolysis remains and is necessary to remove. Further, alumina hydrate covering aluminum nitride grain surface produced by the hydrolysis is stabilized, and it is necessary to restrain the reaction again. For this purpose, the paste-state dross is again heated to 300-500 deg.C. The heating time is ordinarily held to the above temp. range for >=20min, and thereby, the dross becomes dry-state.</p> |
