WIN-WIN: SPENT SAND APPLICATIONS
that’s otherwise useless and turning it into something brand new.”
Making the Most of Metal Unsurprisingly, metal is a key com-
ponent in metalcasting. To that end, the industry has become especially effi cient in all phases of the manufac- turing process, from purchasing scrap metal for recycling to producing cast- ings that eventually can be reused. Scrap Recycling: T e metalcast- ing industry accepts huge amounts of scrap from other manufacturing industries. When a metal component reaches the end of its life, it can be scrapped and reused. Additionally, other manufacturing processes, like stamping, forging and machining, can produce usable scrap. T e environmental benefi ts and re-
duced pressure on landfi lls are obvious. But metalcasters also have an eco- nomic incentive to use what otherwise would be unwanted leftover material. “You’d raise the price of the casting
by 20-40% if you weren’t able to utilize the recycled material,” said Gene Mu- ratore, metalcasting industry consul- tant. “Whatever you pay for those raw materials will aff ect the price of what you’re selling.” According to the U.S. Environmen-
tal Protection Agency, recycling steel reduces air pollution by 86%, water use by 40%, water pollution by 97% and mining wastes by 97% in comparison to using virgin iron. Additionally, using scrap metal requires less energy, which can mean additional savings for the metalcaster. Internal Reuse: Depending on a
casting’s design, a signifi cant amount of metal may be removed from the fi - nal casting. All gates, risers and runner bars will be separated from the casting before it’s ready to be shipped. “T e actual part that’s shipped to
the customer, depending on the cast- ing, may only be 30% of metal that is poured,” said Geoff rey Sigworth, GKS Engineering, Dunedin, Fla. “You have metal in runners, gates and risers. You will also produce scrap castings. All of this is remelted.” Approximately 1% of the metal
will be lost during the melting process May/Jun 2014 | METAL CASTING DESIGN & PURCHASING | 37
When city offi cials in Reedsburg, Wis., discovered a large section of a planned 59-acre industrial park was located near a fl ood area in 2000, they quickly learned the site would require substantial fi lling to be useful. City offi cials approached a Grede metalcasting facility in Reedsburg about delivering its spent foundry sand to the site, less than a mile away. Over the next several years, Grede hauled 230,000 cubic yards of sand
to the site at a cost of about $3.30 per cubic yard. The city installed drain tile, excavated and fi lled portions of the site to provide a level subgrade for the sand. Had Grede sent that same amount of sand to the landfi ll, the cost
would have been $16.20 per cubic yard. In total, Grede saved more than $2.8 million, while the City of Reedsburg saved $900,000 with the free structural fi ll. Fifteen metalcasters in Michigan took a different approach to delivering
sand to destinations other than the landfi ll. More than 20 years ago, the group formed Resource Recovery Corporation (RRC), a cooperative fo- cused on fi nding benefi cial uses for discarded sand and reducing disposal costs in the process. One of the founding members of RRC, Eagle Alloy Inc., Muskegon, Mich., sends all its shell sand, about 12,000 tons annually, to RRC’s facil- ity 25 miles away. The sand is processed for use in several applications, including asphalt mixes, landfi ll leachate collection systems and specialty soils. To date, RRC has recycled more than a million tons of foundry pro- cess residuals and decreased disposal costs by as much as 67%.
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