The presented in the paper investigations were aimed at the determination of the reclaimed material (obtained in the dry mechanical

reclamation process) addition influence on properties of moulding sands with hydrated sodium silicate modified by colloidal suspension

of zinc oxide nanoparticles in propanol. Nanoparticles originated from the thermal decomposition of alkaline zinc carbonate, were used.

The results of the reclamation of the spent moulding sand with hydrated sodium silicate performed in the AT-2 testing reclaimer are

presented in the paper. Both, spent sands from the Floster S technology and from the technology with the modified water-glass were

subjected to the reclamation processes. The following determinations of the reclaimed material were performed: pH reaction, acid demand,

ignition loss and Na2O content. The obtained reclaim was used as a matrix component of moulding sands with water-glass in the Floster S

technology, in which it constituted 60% and 50% of the sand matrix. The strength properties of the prepared moulding sands were

determined (bending strength Rg

u

, tensile strength Rm

u

) after samples storing times: 1h, 2h, 4h and 24 hours.