| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the removing efficiency of impurities and the service life and to reduce the inclusion quantity to a low level by coating a refractory- made aggregate surface with sodium silicate having softening or sticky-fusing point at the temp. of molten Al alloy. SOLUTION: As the refractory-made aggregate, alumina, magnesia, silica, mullite, silicon carbide or these mixtures are used and formed into a porous body having suitable shape from clay state or slurry state and fired to make a porous filter >=6 holes/inch in the mesh. The surface of the aggregate is coated with sodium silicate having the softening or sticky-fusing point at the temp. of the molten Al alloy. The sodium silicate is indicated with a usual chemical formula NaxSiyOz (x=2 or 4, y=1, 2 or 4, and z=3, 4, 5 or 9) as outer soluble salt and meta-sodium silicate, ortho-sodium silicate, etc., are used. In this way, the inner part filtrating filter for removing the fine materials size of about 10-25μm is obtd.</p> |
