Method of making a foamed and expanded product from volcanic glass

Claim 1

IN A METHOD OF MAKING A FOAMED AND EXPANDED PRODUCT FROM VOLCANIC GLASS, THE STEPS COMPRISING MIXING TOGETHER TO FORM A BATCH, FINELY DIVIDED VOLCANIC GLASS AND, AS A FLUXING AND GASSING AGENT, A MIXTURE OF SODIUM NITRATE AND SODIUM HYDROXIDE IN THE PROPORTION OF ABOUT A 5% TO ABOUT A 35% ADDITION OF SAID FLUXING AND GASSING AGENT TO SAILD VOLCANIC GLASS, BASED ON THE NA2O YIELD OF THE FLUXING AND GASSING AGENT, SAID SODIUM NITRATE BEING PRESENT IN SAID MIXTURE TO THE EXTENT OF BETWEEN ABOUT 2 MOL PERCENT AND 98 MOL PERCENT, FIRING SAID BATH WITHIN A TEMPERATURE RANGE OF ABOUT 1300*F. TO ABOUT 2000*F. TO REACT SAID MIXTURE OF SODIUM HYDROXIDE AND SODIUM NITRATE WITH SAID VOLCANIC GLASS AND FLUX AND SOFTEN THE SAME AND SIMULTANEOUSLY TO RELEASE GAS INTO SAID FLUXED AND SOFTENED GLASS FOR SUBSTANTIAL FOAMING AND EXPANDING THEREOF, CONTINUING THE FIRING UNTIL THE GAS RELEASED INTO SAID SOFTENED GLASS PRODUCES A FOAMED AND SUBSTANTIALLY EXPANDED PRODUCT, AND THEREAFTER ANNEALING THE PRODUCT.