PREPARATION AND EXPANSION OF PERLITE ORE FINES

摘要

A process is described for the preparation of perlite ore fines for expansion. The ore fines are treated with an agglomerating agent which has a viscous liquid phase at a temperature above ambient temperature but below the critical dehydration temperature of the perlite ore fines. Suitable agglomerating agents mentioned are the boron acids, particularly orthoboric acid and metaboric acid. The perlite ore fines and agglomerating agent are mixed, preferably by mixing, and then heated to the temperature of the viscous liquid phase and held at that temperature for a short period while the liquid coats at least a portion of the perlite ore fines and effects agglomeration. Thereafter, the agglomerated perlite ore fines can be expanded in a conventional perlite ore expander. The resulting expanded materials have properties essentially identical to standard expanded perlite ore and are useful for such purposes as insulating fillers and light weight aggregates.