The research project investigated the fate of trace metals in rotary kiln incineration with venturi- and packed tower-scrubber particulate- and acid gas-control. A test plan was developed, using a factorial experimental design, to study the partitioning of metals among kiln ash, scrubber water, flue gas particulate, and flue gas vapor. Synthetic waste formulations included the hazardous trace elements arsenic, lead, cadmium, chromium, and barium, as well as the non-hazardous trace elements copper, magnesium, bismuth and strontium, spiked into a clay absorbent material. The independent variables chosen for evaluation were chlorine content of the feed, kiln temperature, and afterburner temperature. Cadmium, lead and bismuth appeared volatile over the range of kiln temperatures tested, while the other six metals displayed refractory properties. Of the three independent variables tested, feed chlorine content had the strongest effect on changes in metal partitioning across the tests; as chlorine content increased, metal volatilization appeared to increase, while scrubber efficiency for metals decreased.

"September 1989". "EPA 600/D-89/208".