| 摘要 |
PURPOSE:To obtain the subject tube having improved strength by calcining a powdery raw material composed mainly of alpha-Al2O3 to convert the alpha-Al2O3 to beta-Al2O3 and crushing the product to obtain powder having a specific sodium aluminate content. CONSTITUTION:Powdery raw materials composed mainly of alpha-Al2P3 having a surface area of >=5m<2>/g and containing Na salt or Na2O and at least one kind of substance selected from magnesia spinel, MgO. Li salt and Li2O are mixed with each other calcined at >=1200 deg.C for >=2hr to convert the Al2O3 to beta-Al2O3 and decrease the sodium aluminate content in the powder to <=4.0wt.%. The beta-Al2O3 is roughly crushed, pulverized to fine powder, slurried by the addition of water and a binder, granulated and dried by a spray dryer and formed to a prescribed form. The formed article is burned at about 1400-1700 deg.C in a burning furnace to obtain the objective beta-Al2O3 tube for Na-S cell. |
