| 摘要 |
<p>Pre comminuted perlite is milled to a particle size of is not >200 mu with >=40% of particles 25 mu. and treating it either during or after milling with alkali soln. contg. 12-21% alkali oxide based on dry mix, forming the wet, half dry or dry powder to produce into bodies of size 2-20 mm. and firing these at 700-1000 degrees C in a counter current rotary oven for at least 5 mins. 0.1-1% of KNO3 may be added to help expansion.</p> |
