To provide an airtight low water-absorbing perlite made from crushed grains such as pearlstone, pitchstone, or obsidian and having properties equivalent to those of fly ash balloons.
The airtight low water-absorbing perlite is formed from crushed grains and takes a balloon form by having many internally formed bubbles and an outer shell that plugs the openings of that portion of the bubbles which are present on the outer hull surface of the perlite. The outer shell is constructed by melting the outer hull surface. The surface melting is performed by further heat-treating the expanded perlite formed by expanding the crushed grains by heating. The low water-absorbing perlite thus has a hollow balloon form and therefore has properties equivalent to those of fly ash balloons.
Masayuki Kishida
Yasushi Takagi
Next Patent: URANIUM RECOVERY METHOD