New technologies address industry needs.

The industry is always searching for new ways to treat foundry waste, and the steel division responded to this continuing need with several key presentations at this year's Casting Congress.

John Svoboda, Process Metallurgy Intl., Arlington Hts., Illinois, asked the steel division attendees, "What do we do with electric arc furnace dust (EAFD) collected in the baghouse, and can we process the dust at less cost than the dumping charges?"

Electric arc furnace dust is estimated to run as much as 650,000 tons annually, most of which is collected in baghouses. These dusts typically contain heavy metals, such as lead, cadmium and zinc, that make the dust a hazardous waste that is subject to landfill disposal restrictions. The dust needs to be detoxified and rendered nonhazardous, and the heavy metals removed and recycled to a smelter. The dust contains approximately 3558% sponge iron and up 56% zinc and smaller amounts of other elements like arsenic, barium and cadmium. The topic of Svoboda's presentation concentrated on the plasma and flame reactor treatments of arc furnace dust (91043). These reactors basically involve the reducution of the oxides (the main component of EAFD) by carbon at elevated temperatures. Svoboda's conclusions were that research into the economics of recovery of baghouse dusts must continue and that both rising toxic substance disposal and raw materials recovery costs make EAFD recycling worth the capital investment.

This session responded to the continuing push for obtaining prototypes faster from casting buyers with a presentation on computer-aided design and pattern making. "Exploiting CAD/CAM in Foundries," (91-049) was the focus of a talk by M. Ashton, SCRATA, Sheffield, England. Several case histories were presented using CAD/CAM to obtain fast prototypes in as little as 2.5 weeks. In particular, a new casting was designed to replace a weldment. The system was aided by a robot to machine the polystyrene pattern. Then a ceramic shell was made and prototypes were poured. This example utilized a 5-axis machining center equipped with a high-speed digitizer to create the complex pattern. This type of equipment can also be used to determine the machining of the final casting.