| 摘要 |
PURPOSE:To make viscosity of granulation slurry and grain diameter of a granulated powder uniform and to reduce generation rate of inner defects and loss rate of a raw material by adding mixing a granulated powder of a specified grain diameter or less which is classified by a cyclone classifier in a process of granulation to a new material. CONSTITUTION:Granulation slurry is acquired by mixing a zinc oxide material which becomes a main element, a metallic oxide raw material such as Bi2O3, Sb2O3, etc., which develops voltage nonlinear properties and a binder are mixed in a mixing tank 2. The acquired slurry is supplied to a spray dryer 1 and granulated, a granulated powder of average grain diameter of about 149mum is supplied to a following process, and a granulated powder of grain diameter of 106mum or less, preferably 63mum or less, is classified by a cyclone classifier 3, which is not disposed of and added into a mixing tank 2 to be mixed with a new raw material. A desirable mixing amount of the classified granulated powder of a specified grain size or less, preferably 63mum or less, is about 3 to 20wt.% to the entire of the new raw material since it especially realizes stable viscosity. |
