Thermodynamic equilibrium predictions of zinc volatilization, migration, and transformation during sludge co-incineration.

Abstract

The effects of interactions between and among chlorine (Cl), sulfur (S), phosphorus (P), and minerals on migration, transformation, and volatilization of zinc (Zn) were numerically simulated in sludge co-incineration using the chemical thermodynamic equilibrium method. Our results showed that all the minerals of Fe2 O3 , Al2 O3 , Fe2 O3 , and TiO2 except for CaO in the sludge co-incineration system reacted with Zn which inhibited the Zn volatilization. The presence of S and P was beneficial to the formation of ZnSO4 (s) and Zn3 (PO4 )2 (s). Cl weakened the chemical reactions between the minerals and Zn, thus increasing the Zn volatilization. Changes in Zn transformation and migration induced by the coupling of Cl+S were mainly controlled by Cl, S, and the minerals, while those induced by Cl+P and S+P were mainly controlled by P and S+P. The presence of P+Cl, S+Cl, S+P, S+Cl+P, Cl, and Al2 O3 in the coexisting mineral system controlled the reactions between the minerals and Zn.