Pneu-Col® applies a reclamation science
that also recovers the extremely
valuable residual clay and additives.

A hydro-acoustic reclamation system known as Pneu-Col®, developed by Furness-Newburge, Inc., has successfully reclaimed green sand by removing the carbonaceous residue off of the sand grains. The research efforts among Penn State University, Neenah Enterprises, Inc. and Furness-Newburge, Inc. have demonstrated the validity of the hydro-acoustic approach for green sand reclamation. The project team successfully made chemically bonded cores with hydro-acoustically reclaimed green sand and this reclaimed sand produced cores and castings of equal or better quality than with previously unused sand. Savings from green sand reclamation include reduced energy to mine the silica, clay and coal and to transport these materials to the facility and reduced energy to transport the waste to a landfill.

In green sand foundries most of the waste sand is generated due to mass balance considerations. The green sand mold defines the outer shell of the cast part and a chemically bonded sand core is inserted into the mold cavity that defines the interior of the cast part. After solidification and cooling, most of the silica sand from the chemically bonded cores is mixed into the green sand system and returned into its molding process. Coal and clay are added in proportion to this additional silica sand input to maintain consistent clay/coal/silica concentrations in the molding sand. Molding sand must be removed from the system to balance out these additions. The coal and clay in the molding sand prohibit its use for core making operations unless treated because it would interfere with its chemical bonding process. Wasted green sand is typically sent to a landfill.

While some foundries implemented thermal reclamation systems to reclaim the silica fraction, these systems are energy intensive because they burn off the clay and coal. In other words, the valuable clay and coal are discarded with this technique. FNI’s production experience and success using AO to recycle clay from bag house dust led the research team to explore developing and modifying the AO process for waste green sand reclamation. The resultant hydro-acoustic sand reclamation process (Pneu-Col®) offers an attractive alternative to thermal reclamation for at least three reasons:

1. The AO process offers the opportunity to recycle the clay and coal in the wasted green sand which is typically 4-5 times the value of the silica on a per weight basis.

2. The recycled clay performs better than new clay.

3. The AO process uses much less energy to reclaim the sand.

4. The AO process does not have the environmental emissions concerns that thermal reclamation does.

The AO sand reclamation process (Pneu-Col®)
is ready for large scale implementation now.

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