Mechanical sand reclamation is a process used in foundries to recover and reuse sand from used molds and cores, reducing waste and costs. Here’s an overview of the key aspects:
1. Purpose of Mechanical Sand Reclamation
– Cost Savings: Reduces the need for new sand purchases.
– Waste Reduction: Minimizes disposal of used foundry sand.
– Environmental Benefits: Lowers landfill use and resource consumption.
– Improved Sand Quality: Removes burnt binders and coatings for better casting quality.
2. Steps in Mechanical Sand Reclamation
# a) Pre-Treatment
– Crushing & Decoring: Breaks down molds/cores into smaller chunks.
– Magnetic Separation: Removes metal particles (e.g., shot, castings).
# b) Primary Reclamation
– Attrition (Scrubbing): Mechanical agitation to remove binder residues.
– Equipment: Vibratory mills, paddle mixers, or centrifugal scrubbers.
– Screening: Separates reusable sand from oversized debris.
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# c) Secondary Reclamation (Optional)
– Air Classification/Dust Removal: Eliminates fine particles and dust.
– Thermal .jpg)
Chemical Reclamation (if needed for high binder removal).
# d) Sand Conditioning
– Cooling: Reduces temperature if thermally reclaimed.
– Additive Mixing: Binders/new sand may be blended for reuse.
3. Equipment Used
– Rotary Drum Reclaimers: Tumble and scrub sand.
– Vibratory Systems: Shake off binder coatings.
– Screw Aerators/Attrition Units: Abrade sand grains to clean them.
– Sand Coolers & Classifiers: Prepare sand for reuse.
4. Advantages Over Other Methods
– Lower energy use than thermal reclamation.
– Faster processing compared to wet reclamation.
– Suitable for clay-bonded and chemically bonded sands.
5. Limitations
– May not fully remove all binders (e.g., some organic residues remain).
– Wear and tear on equipment due to abrasion.
6. Applications
Common in ferrous/non-ferrous foundries using: