Mich., puts it, cradle-to-cradle. “Most foundry sand is cleaner than
native farm soils,” Lenahan said. “In most cases, iron, steel or aluminum casting facilities should not have to worry about their material being haz- ardous. Some brass and bronze casting facilities would have potential concern if they are pouring leaded alloys.” Once you have determined your spent
sand is permitted for use in your state, make an appraisal of the quantities of reusable material routinely available and your current costs for processing and disposing of the material, such as landfill tipping fees, onsite handling costs, cart- age, and other waste management fees, such as container rental costs. Potential users of spent sand often
require large volumes of sand that can be delivered as needed. Small metal- casting facilities have unique chal- lenges when it comes to recycling their materials. Some may find it best to combine similar byproducts from other nearby facilities on a single project. If you do combine materials with other metalcasters, make sure you know there is oversight relative to regulatory compliance for other facilities. Forming a beneficial reuse program
has its own associated fees beyond the regulatory schematic, such as costs for testing and permitting, handling and hauling, and material preparation, such as screening the sand. If you are combining or commingling your byproducts, start- ing a beneficial reuse program will most likely require segregating materials, since end-users typically maintain cleanliness and gradation requirements for each specific end-use. “Te metalcaster has to treat and
approach its casting sand as a product rather than a byproduct,” Lenahan said. “Te customers want clean material, free of core butts and other debris.” Metalcasters also will find that very
few contractors will pay for the sand. “Metalcasters involved in reuse proj-
ects typically are not selling their sand outright; most are paying some fee to have it recycled,” Lenahan said. “Te goal of each metalcasting facility should be to reduce costs associated with disposing of the sand. Not every project can be a home run; however, singles and doubles will win you a lot of games.”
Recycled casting sand can be used in embankment projects. Finding end-uses close at hand makes
a significant impact on the bottom line for the end-user and the metalcaster, since a large portion of the cost is associ- ated with transportation. If you are doing your own hauling, utilizing trucking equipment that can legally handle more tonnage will cut down on the number of trips needed. “Make sure the hauling company
is pulling the optimized load weight each time,” Lenahan said. “Te costs associated with inefficient hauling can radically impact your overall cost of recycling or disposal.” Potential applications for casting
sands include sub-base for construc- tion, including road sub-base, topsoils, landfill cover, leachate liner cover at landfills, asphalt cement, concrete and polymer composites. “Look at what other companies have
done to use casting sand and suggest it to potential new users,” Lenahan said. “You
don’t have to reinvent the wheel. Our business philosophy has been to try not to overreach too far into the abstract but rather stick with what’s been working.”
Case Study 1: Embankment and Structural Fill
Rather than dispose of its excess spent nobake sand in a landfill, Rexnord Industries, Milwaukee, provided more than 20,000 tons of it to the Wisconsin Department of Transportation to use as embankment and structural fill material for major work on the College Ave. interchange of Interstate 94 in Milwaukee. Te use of the sand was permitted under the authority of Wisconsin’s NR 538 Ben- eficial Use of Industrial Byproducts, which covers the use of casting sand in geotechnical applications. Before the sand was accepted for the
project, an independent consultant tested for gradation, soil classification, mois-
CALCULATING POTENTIAL SAVINGS
When building a business case for disposing of sand to a landfill or building a ben- eficial reuse program, the below basic formulas can help calculate potential economic savings. The costs can be calculated on a per ton or volume unit basis. If the beneficial reuse cost is not the same as or lower than the present cost by at least 15-20%, the likelihood of a successful beneficial reuse program is remote.
Beneficial Reuse = (Amortized Capital Investment Costs + Operating Costs + Administrative/Regulatory Costs) - (Byproduct Revenue + Raw Material Costs Avoided + Disposal Costs Avoided + Amortized Tax Reduction Benefit)
Present Cost = Current Amortized Equipment Value + Current Operating Costs + Current Disposal Costs + Current Administrative/Regulatory Costs +/- Current Equip- ment Asset Tax or Depreciation
April 2011 MODERN CASTING | 35
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