| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide molding sand having high heat resistance, excellent low expansibility and excellent friability and applicable even to the casting of a large-sized cast steel article having high pouring temperature, further, having excellent reusability of the sand and inexpensively produced at high yield, and to provide a production method therefor. Ž<P>SOLUTION: An Al<SB>2</SB>O<SB>3</SB>-SiO<SB>2</SB>based refractory raw material 2 such as fired bauxite is melted. The melt 4 is sprayed with gas such as high pressure air by a high pressure air spray device 5, and is cooled and solidified while being scattered in the shape of fine particles. Thus, a melted sphere 6 having the chemical components of ≥70 wt.% Al<SB>2</SB>O<SB>3</SB>and >10 to 12.77 wt.% SiO<SB>2</SB>, comprising an alumina crystal phase as the main constituent in crystal constitution and having a particle size distribution of 30 to 3,000 μm is formed. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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