シリマナイト・ムライト系耐火煉瓦特性の粒度分布依存性

抄録

The packing properties and strength of a body by press moulding and its firedbody were studied of sillimanite refractory batch made by gap-grading. The results obtained were as follow:
a) The spring back phenomenon in press moulding of a grading abound in finer component and a grading having extensive gap, were larger than another grading were.
b) The reduction of volume in press moulding of a grading abound with coarser component was large as like as a grading abound with finer component. It might be considered that the behavior of former was due to the crushing or defacement of grains.
c) The closer packing of fired body could be achieved when a grading having extensive gap (-a grading having the fine component sized finer), and when q of particlesize distribution of pressed body, fell between 0.35 and 0.4 for particles below 3mm, where q was a coefficient in the Andreasen continuous grading. With increasing content of finer component the cold crushing strength also increased.
Another experiment of press moulding and firing experiment of mixes corresponding to the Andreasen continuous grading and the grading having removal tendency of intermediate component of sillimanite, kyanite and synthetic mullite proved that as follow:
d) The closer packing of fired body could be achieved by a continuous grading having removal tendency of intermediate component from a grading having q value of approximately 0.2-0.4 for particles below 4mm. And the content of finer component dependence was observed for permeability.
e) With increasing content of finer component the strength also increased. However, the grading dependence of coarser part was observed especially in cold/hot modulus of rupture.
f) The content of coarser component dependence of thermal spalling resistance was confirmed, and higher resistance could be achieved where the value of q fell between 0.3 and 0.5. Brittle index showed that the grading having removal tendency from Andreasen grading was not so good.
g) The results suggested that sillimanite was a corrosion resistant and thermal spalling refractory due to low porosity, low permeability and high thermal spalling resistance, whereas synthetic mullite was a loadbearing refractory due to high strength, low creep ratio under moderate temperature, high refractoriness under load and low brittle index, however, synthetic mullite was capable of improving by grading for packing properties and thermal spalling resistance.