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Show in the incineration system. For example, chlorine can react with some metals to form new compounds that volatilize more readily. Many metal chlorides are more volatile, as indicated by a lower volatility temperature compared with metal oxides or elemental metals. For example, equilibrium calculations for a mixture containing 5 percent chlorine with all other variables unchanged result in the following lower volatility temperatures: 127°C (260°F) for copper, -15°C (5°F) for lead, 1132°C (2070°F) for magnesium, and 921°C (1690°F) for strontium (4). Calculated volatility temperatures for the remaining metals are not significantly affected by including the chlorine. Incinerator operating variables that affect metal vaporization are expected, in turn, to affect the distribution of the volatile metals among the particle size ranges. These variables include the kiln temperature and the chlorine content of the waste feed. These are noted in Table 4, along with the secondary variables of flue gas velocity in the kiln and the particulate loading (mg/actual wet m3 ) in the afterburner exit. These secondary variables are noted since they either influence or indicate the degree of entrainment of particulate into the flue gas. Figures 2 and 3 show the variations in the distributions of the metals among the particulate size fractions as a function of kiln exit temperature and waste feed chlorine content, respectively. Cumulative distributions of less than 4 ~m and less than 10 ~m for each metal, and for the total particulate sample, are given. The figures correspond to the groupings of tests in Table 4. Values for the three center replicate test points were averaged and plotted as a single point. Metal particulate distributions are plotted against the volatility temperatures to facilitate comparison of relative metal behavior. For the test conducted with a nominal kiln exit temperature of 816°C (1500°F), Figure 2 indicates that the distributions of metals in the particulate fractions of less than 4 ~m and less than 10 ~m were essentially the same as those for the overall particulate sample. About 10 percent of the total particulate sample was less than 4 ~m and about 10 percent of most metals were in the less than 4 ~m size fraction; about 20 percent of the total particulate was less than 10 ~m and about 20 percent of most metals were in the less than 10 ~m particulate. A slight shift to finer particulate (less than 10 ~m) is seen for arsenic and cadmium. Metals present in flue gas particulate solely via entrainment are expected to exhibit a size distribution similar to that of the overall flue gas particulate, provided no significant vaporization of metals from the entrained particulate occurs. Thus, at low kiln temperature, the data suggest that the metals were present in the flue gas particulate primarily through entrainment, and did not experience significant vaporization. 10 |