Removal of halogens from Pb-bearing dust by alkaline washing

Release time:2023-01-07

Impact Factor:4.217

DOI number:10.1016/j.hydromet.2022.105838

Journal:Hydrometallurgy

Key Words:Pb-bearing dust, Halogens, Dechlorination, Alkaline washing

Abstract:Pb-bearing dust with a high halogen content is produced in the smelting process of scrape‑lead recycling, it is important to remove halogens before valuable metal recovery. First, this study investigated the mineralogical composition of halogens, including water-soluble KCl, KCdCl3, K4CdCl6, and CdCl2, and water-insoluble PbClF, Pb5(AsO3)3Cl, and TlI. Second, alkaline washing was conducted to remove halogens from Pb-bearing dust. The results show that 77.0% Cl could be removed by water washing at 25◦C, while only 22.7% F, 31.4% Br, and 11.1% I were removed. The Cl and F removal efficiencies changed negligibly with the increase in temperature. However, under the optimum Na2CO3 washing conditions using Na2CO3 concentration of 25 g/L at 80◦C and liquid/solid ratio of 6:1, the Cl, F, Br, and I removal efficiencies were 86.5%, 67.7%, 82.7%, and 78.8%, respectively, indicating that the Cl and F removal efficiencies could be significantly improved by adding Na2CO3. The halogens in the form of KCdCl3, KCl, CdCl2, and PbClF could be efficiently removed, converting Pb and Cd to carbonates retained in the dehalogenated residue. However, it was difficult to remove Cl from Pb5(AsO3)3Cl, with a compact and smooth rod-like structure.

Indexed by:Journal paper

Discipline:Engineering

First-Level Discipline:Metallurgical Engineering

Document Type:J

Volume:209

Page Number:105838

Translation or Not:no

Date of Publication:2022-02-16