01-system-sand-used-sand-sand-after-casting-process-over-01-core-sand-sand-core-silica-sand-mixed-with-core-oil-sodium-silicate-sand-Properties-Of-Moulding-Sands-01-core-sand-sand-core-silica-sand-mixed-with-core-oil-sodium-silicate-sand-Properties-Of-Moulding-Sands-properties-of-moulding-sands.jpg