A method and a device for reclaiming green waste foundry sand
Aim: To reclaim waste foundry green sand in an affordable way and thereby use it again in the foundry. The use of reclaimed sand in small scale foundries would improve the economics and efficiency of the process. It also proposes the best possible use of fines (dead clay) generated during reclamation.
Uniqueness
Two-stage attrition device involves only mechanical treatment and only dead clay coating is removed from sand grains without affecting the sand properties.
What we offer
- Two-stage attrition device for small scale foundries
- A big plant for foundry clusters (say 20-25 foundries)
- Complete analysis of reclaimed sand
- Recommendation for better casting based on the analysis
- Best possible use of fines generated in reclamation
- Retrofitting of two-stage device in foundries at their existing sand plant
Benefits
- Improved economics of the foundries considering the rise in fresh sand prices
- Reduction in occupational and health hazards due to reclamation of waste sand
- Foundries can be partially independent on the sand mining
- Zero waste foundries can be established
The green waste foundry sand having deactivated binder coating is subjected to external attrition in a rotary non-perforated drum having a feed end and a discharge end and rotating about a horizontal axis at 10-50 rpm by feeding the sand into the non-perforated drum at a feed rate of 1.4 – 2.0 kg min-1 and allowing a residence time of 30-60 minutes for the sand in the non-perforated drum. The sand emerging from the non-perforated drum is subjected to inter-particle attrition in a rotary perforated drum rotating with the non-perforated drum about the same horizontal axis. The sand is allowed a residence time of 5-15 minutes in the perforated drum. The volume ratio between the non-perforated drum and the perforated drum is 2.5 to 4.
Chemical Engineering