Thermodynamic Equilibrium Simulations of Thallium Distributions in Interactions with Chlorine, Sulfur, Phosphorus, and Minerals During Sludge Co-combustion

Abstract

Effects of interactions among chlorine (Cl), sulfur (S), phosphorus (P), and minerals on thallium (Tl) distributions were simulated using thermodynamic equilibrium conditions during the sludge co-combustion. Our results showed that Tl mainly existed in the forms of Tl2O3(s) and Tl(g) and did not react with SiO2, Al2O3, CaO, Fe2O3, and TiO2. Cl generated TlCl(g) and Tl(g) which in turn promoted Tl volatilization. S produced Tl2SO4(s), thus inhibiting Tl volatilization. P existence had no influence on Tl volatilization. With the couplings of Cl + S, S + P, and Cl + S + P, the reactions between single minerals and Tl were mainly controlled by S but P and Cl. With the Cl + P coupling, Cl controlled the reactions between the minerals and Tl, while P and the minerals had no significant impact. With the coupled minerals of SiO2 + CaO + Al2O3, S exerted a more influence than did Cl and P on the distributions of Tl, thus preventing Tl emissions.