Presented are results of a research on usability of an innovative reclamation process of microwave-hardened moulding sands containing

water-glass, combined with activation of binder. After each subsequent stage of reclamation, quality of the reclaimed material was

determined on the grounds of measurements of permeability and results of screen analysis. The reclaimed material was next used again to

prepare new moulding sand. The sandmix based on high-silica sand prepared with water-glass grade 145, was subject to the following

cyclical treatment operations: mixing components, consolidation, microwave hardening, cooling, heating the mould up to 800 °C, cooling

to ambient temperature, mechanical reclamation dry and wet. It was found that the used-up and reclaimed sandmix containing water-glass

is susceptible to the applied activation process of thermally reacted film of binder and, in addition, it maintains good quality and

technological properties of high-silica base. Observations of surfaces of reclaimed high-silica grains with activated film of reacted

inorganic binder were carried-out using a scanning microscope. Thanks to properly selected reclamation parameters, the high-silica base

can be reused even five times, thus reducing demand for fresh aggregate and inorganic binder.