Virginia Tech Recycling - Coal Ash Recycling UpdatedBy Larry Bechtel
Spectrum Volume 17 Issue 20 - February 16, 1995
Like the recycling of other materials (such as corrugated cardboard and steel cans), the recycling of coal ash is a return to a mode of operation abandoned 10 to 15 years ago. At one time, according to Power Plant superintendent senior Rodney Altizer, Wytheville Block Company collected the ash for use in its cement products. But revised regulations designed to protect public health and safety ended this arrangement. For years, Tech tried to find another taker. "We tried our best," said Altizer. "Marshall Concrete even experimented with a backfill product. But we were forced to landfill the ash."
This changed with Ash Technologies Inc, of Chattanooga, Tenn. As Altizer expressed it: "When ATI called, I lit up like a bulb." In business since 1988 and with 26 contracts throughout the Southeast, ATI specializes in using coal ash. According to Richard Pincelli, president and owner of ATI, the procedure is to take a sample of the ash, analyze its chemical properties, and find a user. In the case of Virginia Tech's coal ash, the user turned out to be Roanoke Cement Company, which ATI pays for taking the ash. "Some of the chemistry is advantageous (for making cement) and some is not," said Pincelli. Nevertheless, Roanoke Cement agrees to take and use all the ash.
Under the agreement, ash from the Power Plant is loaded into tandem trucks, wetted down to control dust, and trucked to Roanoke Cement by Goff Trucking of Shawsville. The trucks are then dumped, and the ash included as a raw material in making Portland Cement, which is then sold in bulk to a variety of concrete-manufacturing companies.
The addition of coal ash to the cement mixture "changes a few ratios," said Donald Levonian, Roanoke Cement assistant plant manager. To meet standard targets for calcium, silicate, and lime in the finished cement, the company uses about 65 percent shale and 30 percent limestone. "But our quarry reserves are about 50/50. Because silica, aluminum, and iron are the primary components of coal ash, adding ash causes a greater need for limestone, which reduces the need for shale, so the use of coal ash balances our quarry reserves through a corresponding decrease in the need for shale."
Levonian said Roanoke Cement itself already burns 125,000 tons of coal per year, generating 12,000 tons of ash annually for use in cement making. The Pincelli group provided an additional 30,000 tons annually from eight different sources, including Virginia Tech.
Overall, the ATI contract pleases Altizer. "It costs a little more than our old contract, but it's environmentally responsible. The contract is likely to significantly increase Virginia Tech's recycling percentage, as well."