Sand Binder Reduces Emissions, Cuts Energy Costs.

Today's chemical-based sand binders for coremaking present environmental problems for foundries related to emissions. Homel Foods, Austin, Minnesota, is producing GMBOND sand binder, an environmentally friendly product, that helps foundries address this issue.

The binder is made of 99.5% protein, a renewable natural resource, combined with a small amount of iron oxide (less than 0.1%) to increase the thermal degradation of the binder. Bonding is accomplished by dehydrating the wet core sand mixture. During this process, the biopolymers in the protein binder form bonds in a crystalline structure. This binder does not activate by chemical reaction.

A small amount of preservative also is added to ensure long bench life while the mixed core sand is wet. This protein binder is completely water soluble, which simplifies core removal and allows sand to be continuously reused. The binder thermally degrades at temperatures as low as 450C (842F).

The non-toxic proteinbased binder provides strengths equal to phenolic urethane coldbox processes with significant environmental benefits, energy cost reduction and shakeout ease. Tests have shown it can reduce emissions during the coremaking process up to 89% for aluminum and up to 99% for iron.

Recently, the binder underwent extensive testing as part of the Casting Emission Reduction Program (CERP), a joint program of the U.S. Dept. of Defense and the U.S. Council for Automotive Research. The purpose of CERP is to evaluate alternative methods and materials for their effectiveness in reducing air emissions from foundries. The results of CERP's pre-production qualification tests showed that, when compared to a phenolic urethane binder used for baseline comparison, the protein binder reduces emissions of:

* hydrocarbons by 86% with iron casting;

* volatile organic compounds by 63% with aluminum and 91% with iron;

* hazardous air pollutants by 53% with aluminum and 91% with iron;

* polycyclic organic materials by 89% with aluminum and 99% reduction with iron.

ALUMINIUM

Pounds of toxic materials per ton of metal

GMBOND [R]

Phenollc Urethnane CERP baseline greensand


Volatile Organic Compunds VOCs    -63%
Hazardous Air Pollutants HAPs     -53%
Polycylic Organic Materials POMs  -89%


Note: Table made from bar graph
IRON

Pounds of toxic materials per ton of metal

GMBOND [R]

Phenolic Urethane CERP baseline iron


Hydro-carbons                   -85%
Volatile Organic Compunds VOCs  -91%
Hazardous Air Pollutants HAPs   -91%
Polycyclic Organic Materials    -99%
POMs


Note: Table made from bar graph