Fundamental Studies of Metal Behavior During Solids Incineration

An experimental apparatus was constructed which allows investigation of the vaporization behavior of metal contaminants during incineration of their host substrate. Comparisons were made between equilibrium predictions and experimental observations for a number of different metals in chlorinated, inert, and reducing environments between 150°C and 650°C. The equilibrium predictions for Pb vaporization were found to show the greatest deviation from experimental observations. Comparisons showed that a knowledge of elements associated with the initial metal species, as well as omission of PbCl₄from the calculations, can be important for the equilibrium predictions. Experimental results showed that the formation of volatile PbCl₄predicted by equilibrium was not kinetically favorable under the conditions studied. Subsequent vaporization studies involving PbCl₂deposited on a silica substrate demonstrated an influence of initial concentration on the amount of Pb vaporization observed. The extent of vaporization appeared to be independent of a moderate increase in temperature and an increase in the time allowed for vaporization.