Heavy Metal Outputs from a Cement Kiln Co-fired with Hazardous Waste Fuels
Qizhong Guo, James O. Eckert, Jr.
Journal of Hazardous Materials, Vol. 51, 1996, pp. 47-65
Abstract
Measured data from a kiln equilibration tests are analyzed for heavy metal outputs from
a cement kiln co-fired with hazardous waste fuels. Metal outputs from stack emissions, cement
kiln dust and cement clinker are considered. Equations are derived for predicting all three
metal outputs at any hazardous waste feed rate under steady state conditions. Through
analysis of two steady state conditions, at the beginning and end of the equilibration test,
essentially the same ratios of metal feed rates are found to be distributed to the kiln dust
at either high or low metal feed rates. Applying the same distribution ratios in the derived
equations, metal concentrations of wasted kiln dust are predicted when the kiln is not using
hazardous waste fuels. Measured concentrations of arsenic, beryllium, cadmium, chromium, and
lead in wasted kiln dust, at the highest intended hazardous waste feed rates to the kiln, are
68, 10, 72, 18, and 68 times those predicted for feed rates with no hazardous waste. In
addition, the intermediate, non-steady state segment of the equilibrium test is analyzed. If
metals are assumed not to accumulate in the kiln, the intermediate metal concentrations in
cement clinker are predicted to be substantially higher than those at the final steady state.
