Novel pathway of stabilized Cu2S volatilization by derivated CH3Cl

Abstract

Stabilized heavy metals-containing phases and low chlorine utilization limit heavy metals chlorination reactions. The traditional method of adding chlorinating agents can promote heavy metals chlorination volatilization, but the limiting factor has not been resolved and more chlorides are emitted. Herein, a new reaction pathway to promote heavy metals chlorination volatilization through the transformation of stabilized heavy metals-containing phases and chlorine species by the addition of biomass at the sintering is first reported. The Cu volatilization efficiency increased sharply from 50.50% to 93.21% compared with the control, Zn, Pb, and Cd were nearly completely volatilized. Results show that the biomass carbonization process was more important for Cu chlorination volatilization. Stabilized heavy metals-containing phases were converted from Cu₂S to CuO and Cu₂O with the biochar and oxygen, increasing the activity of Cu. The chlorine species KCl reacted with CH₃-containing groups to form CH₃Cl, which reacted with CuO with a lower Delta G than HCl and Cl₂, increasing the tendency for the conversion of CuO to CuCl. Cu chlorination volatilization process, following shrinking core kinetic model and controlled by chemical reactions. The outcomes fundamentally addresses the limiting step for heavy metals chlorination volatilization, supporting the incineration fly ash harmless treatment.

Keywords: Biomass; Chlorine species; Heavy metals-containing phases; Incineration fly ash; Promotion mechanism.