Investigating On The Mechanical Reclaiming Ability Of Sodium Silicate Used Sand By Non-normal Temperatures Action

Green manufacture is a developing trend in the industry production of the 21st century, and sodium silicate sand is the most possible mold sand to realize green casting. To realize green casting, the most difficult question is how to reclaim completely the sodium silicate used sand. Over the years, many different methods of sodium silicate sand reclamation have been tried. They could partly reclaim the sodium silicate used sands, but always have some defects hard eliminated. So it's very urgent to find some new ways to solve the question of sodium silicate used sand reclamation.In this paper, two new methods for sodium silicate used sand reclamation have been discussed and tested. One is the"thermal-mechanical"reclamation; another is the"freezing -mechanical"reclamation.In order to complete the tests, a suit of reclamation equipment has been developed at first, then the reclamation process parameters and the reclamation effect of the two new methods have been carried through, and lastly, the mechanisms of the two new reclaiming methods have been discussed. Through orthogonal experiments, the best reclamation processing parameters of the two new reclaiming methods have been obtained. The best reclamation processing parameters of the"thermal-mechanical"reclamation should be that reclamation time 8 min, reclamation rotate speed 1000r/min and heated temperature 400℃, and its removing ratio of the remnant film on sodium silicate used sand could be reached about 25%. The best reclamation processing parameters of the"freezing -mechanical"reclamation should be that reclamation time 4 min, reclamation rotate speed 1000r/min, the containing water amount 10% and the freezing temperature -40℃, and its removing ratio of the remnant film on sodium silicate used sand could be reached about 40%.The mechanisms of the two methods have been researched and analyzed. The mechanism of the"thermal-mechanical"reclamation method would be that the amount of dissoluble Na2O is decreased and the mechanical properties of remnant film are debased because of the sodium silicate sand being heated, so it will improve the mechanical reclamation effect by heating sodium silicate used sand. The mechanism of the"freezing -mechanical"reclamation method would be that the remnant film on sodium silicate used sand will expand by dissolving an amount of water, and the water becomes ice and the remnant film becomes more brittle after the sodium silicate used sand is frozen, so it will improve the mechanical reclamation effect by freezing the used sand.