Volatility of arsenic in contaminated clay at high temperatures

Incineration is commonly used to decontaminate soils polluted with organic compounds but may lead to volatilization of heavy metals present in the soil. Tube furnace experiments were conducted to investigate the volatilization of arsenic from kaolin clay contaminated with the metal. At 522 degree C, arsenic volatilization was less than or equal to 22% in all atmospheres tested. At 1125 degree C, about 40% of the arsenic volatilized in oxidizing and inert atmospheres, but in reducing and hydrogen-chloride-containing atmospheres, 82 92% and 91 98%, respectively, of the arsenic volatilized. Results suggest that arsenic in incinerated soils is largely retained in the ash unless temperatures are very high or incinerator gases are reducing or contain high concentrations of hydrogen chloride.