'Freezing-mechanical' reclamation of used sodium silicate sands

摘要

The remnant binder on the surface of used sodium silicate sands can be dissolved in water. When frozen at low temperature, the hydrous remnant binder in moulding sands can become brittle, which is beneficial to strip remnant binder from the sand surface by means of mechanical force. A study of the 'freezing-mechanical' reclamation of used sodium silicate sands is reported. It is shown that 'freezing-mechanical' reclamation can be more effective than dry mechanical reclamation of used sands. The mechanical properties of remnant binder were found to change under freezing condition, which is propitious to the dry mechanical reclamation processing. The moisture content and freezing temperature of the used sands influenced reclamation effectiveness. The optimum moisture content was ～10%, and the lower the freezing temperature, the more favourable the reclamation of the used sands.