Carbon dioxide cured sand molds employing dry sodium silicate binder

Claim 1

A COMPOSITION OF MATTER USEFUL FOR MAKING SAND CORES AND MOLDS CURABLE BY SUBJECTING TO AN AMBIENT ATMOSPHERE COMPRISING CARBON DIOXIDE GAS CONSISTING OF A MIXTURE OF FOUNDRY GRADE SAND AND A POWDERED DRY SODIUM SILICATE, COMPOSED OF BETWEEN 0.5 AND 1.5 MOLES OF SIO2 PER MOLE OF NA2O, AND IN AN AMOUNT OF AT LEASE 2 PARTS OF THE SODIUM SILICATE WHEN THE MOLAR RATION OF SIO2 TO NA2O APPROACHES 0.5 AND IN AN AMOUNT OF AT LEAST 3 PARTS PER 100 PARTS OF SAND, WHEN THE MOLAR RATIO OF SIO2 TO NA2O APPROACHES 1.5, AND WATER IN AN AMOUNT SUFFICIENT TO MAKE A MOLDABLE MASS BUT NOT SUBSTANTIALLY IN EXCESS OF THE WEIGHT OF THE SODIUM SILICATE EMPLOYED.