Sand reclamation refers to the process of recycling and reusing used foundry sand or industrial sand from casting operations. This is important for both economic and environmental reasons, as it reduces waste and the need for new raw materials.
Key Processes in Sand Reclamation
Mechanical Reclamation:
- Involves abrasion, screening, and air classification.
- The aim is to remove binder residues and contaminants from the sand grains.
- Often used as a first step in the reclamation process.
Thermal Reclamation:
- Uses heat to burn off binder coatings on sand grains.
- Can be energy-intensive but effective in completely removing organic binders.
- Temperature and time control are critical to avoid damaging the sand.
Chemical Reclamation:
- Employs chemical agents or solvents to dissolve and remove binder residues.
- Often used in conjunction with mechanical processes.
- Requires careful handling of chemicals and waste management.
Benefits of Sand Reclamation
- Cost Savings: Reclaimed sand reduces the need for purchasing new sand, lowering overall production costs.
- Environmental Impact: Recycling sand minimizes waste disposal and reduces the environmental footprint of foundry operations.
- Resource Efficiency: Improves the sustainability of operations by making efficient use of available materials.
Mechanical Reclamation System
A typical mechanical reclamation system will include the following sequence of components:
- Shakeout Deck
- Attrition Mill
- Elevating Device
- Surge Hopper
- Magnetic Separator
- Agglomerate Screener
- Fluid Bed Classifier (Cooling Optional)
- Elevating or Pneumatic Transportation Device
- Bulk Storage Silo for Mechanically Reclaimed Sand
- Dust Collector
A basic mechanical reclamation system is a good choice for foundries who:
Shakeout when sand is 250°F or lower
Have throughput requirements not exceeding 6-8 TPH depending on resin system, metal poured, sand:metal ratio, etc.
Do not need to cool their sand prior to leaving the reclamation system
Have few, if any, chills in their molds
Conclusion
Sand Reclamation is the physical, chemical, or thermal treatment of used foundry casting sands so that they can safely and effectively be re-used for molding and coremaking applications.
A mechanical reclamation system uses motion energy to physically break down chunks of spent casting sand into a clean, usable, grain size sand.