| 摘要 |
<p>Lightweight aggregates are produced by coating vermiculite with silicate of soda or the like, together with finely divided powdered glass or commercial glazing compounds or like vitreous material and subjecting the coated mass to heat treatment to melt together and vesiculate the coating materials distributed over the surface of the vermiculite which is fully exfoliated. Before heating the aggregate may also be coated with precipitated chalk, powdered limestone or borax, or a shale, clay, or expandable rock such as pumice or perlite. In a modification the pre-exfoliated vermiculite is substituted for the raw vermiculite. Heating is preferably effected in a rotary kiln using a direct flame or by radiation from the heated furnace linings, the material being passed through by a vibratory system. The aggregates may be bound by means of cement or a silicate of soda flux and the voids may be filled with sand, crushed rock, or foamed slag or perlite, and may be pressed into blocks or slabs, which may be reinforced with steel.</p> |
