| 摘要 |
PURPOSE:To obtain ceramic filter medium excellent in removal of contaminated matters and back-washing efficiency by preparing ceramic filter medium containing 30% or more of Al2O3, with numerous pores, particle diameter of 0.5-1.0mm, apparatus specific gravity of 0.6-0.8, and specific surface area of 1m<2>/g or larger. CONSTITUTION:Kaolin not including free silicic acid of 40-60%, aluminum hydroxide of 0-5%, magnesite or seawater calcined magnesia of 10-25%, and elutriation clay not containing free quartz sand of 10-25% are mixed together. Thereafter, water is added to said mixture in a trommel to pulverize it and said mixture is dewatered in a filter press and is kneaded in an auger machine and then is formed into a plate-like article. And then, said article is dried and then baked in a tunnel furnace at temperatures in the range of 1380-1410 deg.C, following which the baked article is roughly crushed by means of a crusher and screened so as to adjust the particle size to 0.5-1.0mm. In this manner, ceramic filter medium having excellent removal efficiency for contaminated matters, back-washing efficiency, long durability, high recovery rate and chemical resistance can be obtained. |
