Foundry Sand

FinnSand™ – Thermally Regenerated Foundry Sand

Thermal regeneration refers to a thermal treatment of foundry sand. In the process, organic binding agents burn at a high temperature, while silica sand does not oxidize or otherwise react with numerous substances. The end result of this process is silica sand that is so pure that it is the equivalent of virgin foundry sand.


Treating the sand at a high temperature causes the silica sand to undergo a phase change from alpha-quartz to beta-quartz at approximately 573 °C (1063.4 °F). This affects the sand’s thermal expansion behavior when the sand is reused in casting, making thermally treated foundry sand more stable in the casting process. The high temperature can also break weak sand structures, which then fly away as dust. When the fine particles that cause irregularities are removed from the sand, the quality and performance of a foundry’s sand system improve.


Fast and Flexible Sand Treatment Service

Finn Recycling Oy offers foundries purification services of used foundry sand using both thermal and thermal-mechanical methods. The comprehensive service includes collecting the used sand from the customer and then delivering the new, purified sand back to the customer.


The quality parameters of the sand are determined together with the customer:

  • pH
  • Electrical Conductivity
  • Grain Distribution
  • Loss on Ignition