HOUGHTON,MI--Within the next five years, residents of the Great Lakes region may see their dependance on road salt decrease, along with a decrease in landfill wastes. Michigan Technological University researchers are looking at the feasibility of road salt alternatives, while also examining potential uses for recycled goods.
Kip Paxton, Jim Hwang, and Allison Hein of the Institute of Materials Processing (IMP) at MTU are working on alternatives to current glass recycling practices. In a project sponsored by the Michigan Department of Environmental Quality, IMP found waste glass to be a suitable replacement for silica in sandblasting, and a useful additive in clay, tiles, brick, and glass. Among the list of alternatives for further study is a method that incorporates glass, limestone waste, and food wastes to form Trac + Deicer. This product, which is a mixture of crushed glass and calcium magnesium acetate (CMA), is being considered as an alternative to road salt and sand for the de-icing of winter roads.
Studies of CMA conducted by the Michigan Department of Transportation and others have shown that when applied early it can be as effective as salt for keeping snow from packing on the road surface. A very important feature of CMA is that it is much less corrosive than salt; it is one-fifth as corrosive on steel and one-tenth as corrosive on aluminum. This has serious implications due to the high annual cost of repair to roads, bridges, and cars made necessary by the current use of salt for de-icing. Because airplanes are made of aluminum, airports already rely exclusively on CMA to keep runways clear. Another important benefit of CMA is that it sticks to the road surface and continues working for longer periods than salt.
Currently, CMA is very expensive, averaging $700 per ton compared to $30 per ton for salt. However, using waste materials such as food and agricultural wastes should reduce the cost, according to Hein, a research engineer of IMP and a member of the Upper Peninsula recycling coalition. Because food wastes are used to make a primary component, manufacture of CMA would also reduce the amount of garbage taken to landfills. The other essential ingredient, limestone waste, can be found in local limestone quarries in the form of particles that are too small to be used in standard industrial processes. Thus, Trac + Deicer combines three waste products and results in reduced landfilling.
IMP Researchers intend to look at the manufacturing processes of CMA. They hope to achieve several things: locating the most effective and economic methods of procuring the products locally, incorporating these products into a process that can be performed at the local level, and educating the road commission about the best ways to apply the chemical. The ultimate goal, according to Hein, is a process that would allow money spent clearing roads to stay in the community.
Another winter use of recycled glass is as a substitute for sand when it is ground and used to provide traction; this method is already being implemented in parts of Canada and Alaska. These uses are important to investigate because the type and color of the glass used for traction is irrelevant. Hein said, "Some glass is difficult to recycle. Clear glass can be melted and reused for containers, but mixed color glass and non-container glass is much more difficult to reuse."
As recycling plans become more popular across the country, it is important to find uses for the recycled material, according to Hein. "There is more to the cycle than just recycling," she says, "We must produce a useful product, and people need to be willing to buy recycled goods. This product can help us achievethat goal."
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For more information, contact Allison Hein at 906-487-1821 or e-mail: amhein@mtu.edu.