Dechlorination of auto shredder residues

Abstract

Dechlorination of ASR (auto shredder residual) wastes has been studied in the present work. ASR was predechlorinated with Ca(OH) 2 extraction as well as dechlorinated with Ca(OH) 2 during incineration or pyrolysis. Experimentally, pre-dechlorination of ASR via extraction of Cl with a Ca(OH) 2 solution (pH 12.5) may reduce Cl contain in the ASR by 15%. Extraction of Cl at elevated temperatures (such as 373 K), interestingly, led to a further reduction of Cl in the ASR to 33.5%. A small amount of HCl and light hydrocarbons (C 1–C 5) were yielded during pyrolysis of the ASR in the presence of Ca(OH) 2 at 773 K. On the contrary, 75–85% of Cl may be mineralized (CaCl 2) with Ca(OH) 2 (or CaO) during incineration at 1100 K.