Efforts to reclaim sand within a facility and reuse spent sand reduce the industry’s demand for newly mined materials.
manufacturing industries. Other manufacturing processes, like stamp- ing, forging and machining, can pro- duce usable scrap. Additionally, when a metal component reaches the end of its life, it can be scrapped and reused. Te environmental benefits and reduced pressure on landfills are obvi- ous. Metalcasters use what otherwise would be unwanted leftover material, which reduces a casting’s final cost. “You’d raise the price of the casting
by 20-40% if you weren’t able to utilize the recycled material,” said Gene Muratore, metalcasting industry con- sultant. “Whatever you pay for those raw materials will affect 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 a metalcasting operation. Internally, all gates, risers and
runner bars will be separated from the casting before it’s ready to be shipped. Approximately 1% of metal will be lost during the melting process in dross and slag. Depend- ing on the casting, machining also may result in metal loss. But for the large majority of casting operations, somewhere in the neighborhood of
95% of the as-cast part will eventu- ally exit the metalcasting facility as the finished casting. Costs are involved in processing
and reusing metal, but the overall effi- ciency of the operation means waste remains relatively small. Additionally, the castings that exit a metalcasting facility could potentially become scrap that may head to another metalcasting facility for a second or third life. “Metal doesn’t have a memory,” said
Geoffrey Sigworth, GKS Engineering, Dunedin, Fla. “It doesn’t know or care it was a casting yesterday.”
Reclaiming and Reusing Sand
Foundry sand, which is used by 60% of metalcasters for molds and cores, represents a significant industrial byproduct. Due to increasing regula- tory control and disposal costs in the last 30 years, metalcasters have reduced the amount of sand headed to landfills. Te industry discards between 5-8
million tons of sand annually. How- ever, according to a recent industry study, prior to being discarded, the average sand grain is reclaimed and reused by the metalcaster an average of eight times. Additionally, approximately
30% of foundry sands are reused in non-landfill applications, includ- ing geotechnical fills, road sub-base, embankment construction and soil additives. Despite the advancement of
recycling initiatives, it is not neces- sarily a revenue-generating endeavor. Processing costs to get the material to “product quality” typically consume any margin in the sale price. However, beneficial reuse minimizes disposal costs and produces environmental benefits—a win-win for the met- alcaster and its community. For an industry with a significant number of small facilities, metalcasters should engage government officials and community leaders to explore possible beneficial reuse programs. Bryant Esch, environmental coordina- tor, Waupaca Foundry Inc., Waupaca, Wis., encourages dialogue between metalcasting facilities and the local community and government. “Everyone should interact with their state regulators. Have a discus- sion—this is what we have, this is what we want to do,” Esch said. “Start with smaller projects to get you going. Each foundry needs to pick projects that are feasible. Whether it’s a project with the local community that is great PR, whether it’s a small project that allows you to start beneficial reuse, you need to pick the project that works for you. And, as you’re doing it, make sure to stay focused on project management.” According to EPA estimates, beneficial use of discarded sand is saving more than 202 billion BTUs per year and reducing CO2 emissions by 20,000 tons. EPA has determined
June 2014 MODERN CASTING | 29
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