Recovery of Lead and Silver from Zinc Leaching Residue Using Methanesulfonic Acid

Abstract

A solvometallurgical route for the recovery of lead and silver from the leaching residue of the zinc roast-leach-electrowin process was developed. Methanesulfonic acid was selected as the lixiviant because of the high solubility of lead and silver methanesulfonate salts. The direct leaching of the residue with methanesulfonic acid showed a high codissolution of gypsum and a low dissolution of lead (present as anglesite), requiring a high liquid-to-solid ratio. Two pretreatment processes were investigated to improve the leaching efficiency. First, the gypsum was selectively removed via Randall extraction using water as a solvent. Pure gypsum was obtained in this step, and the solvent could be reused multiple times. Second, the solubility of lead was increased by transforming the anglesite into cerussite via a carbonation reaction with sodium carbonate. When the carbonation reaction was performed before the removal of gypsum, a significant excess of sodium carbonate was required because the gypsum was also transformed into calcium carbonate. However, when the carbonation was done on the gypsum-free material, a stoichiometric amount of sodium carbonate was sufficient. The carbonation reaction drastically increased the lead dissolution, and the liquid-to-solid ratio requirements decreased. The leaching efficiency for both silver and lead using methanesulfonic acid as the lixiviant after Randall extraction and the carbonation reaction was around 80%.

Extraction of Lead and Zinc from a Rotary Kiln Oxidizing Roasting Cinder

“…Pyrite reacts with oxygen to form hematite (Fe 2 O 3 ) or magnetite (Fe 3 O 4 ). The main chemical reactions that may occur in the sulfuric acid leaching system are shown in Equations (1)- (16), and these are confirmed by characterization results, as described below.…”

Citrate-Mediated Hydrometallurgical Lead Extraction and Integrated Electrochemical Recovery from Zinc Leaching Residue

“…Mineral phases are reported to consist of anglesite (PbSO 4 ) and gypsum (CaSO 4 ·2H 2 O) which account for 35% and 25% of the material, respectively. Other constituents in the material include calcium hydroxide (Ca­(OH) 2 ), sphalerite (ZnS), and iron arsenate (Fe 3 (AsO 4 ) 2 ) with a mass percentage of 6%, 4%, and 2%, respectively . Other impurities have low concentrations and little effect on the extraction of Pb.…”

“…Other constituents in the material include calcium hydroxide (Ca(OH) 2 ), sphalerite (ZnS), and iron arsenate (Fe 3 (AsO 4 ) 2 ) with a mass percentage of 6%, 4%, and 2%, respectively. 26 Other impurities have low concentrations and little effect on the extraction of Pb.…”

Lead Electrodeposition from Triethylenetetramine Solution Containing Inhibitors

“…Metals 2021, 11, 1330 3 of 12 [22]. A main drawback of this technology is the necessity to have lead carbonate instead of lead sulfate in solid materials, which usually requires one additional unit operation.…”

“…Ethylenediamine and diethylenetriamine have proven to be promising leaching and electrowinning candidates for nickel and copper production from hydroxide sludges [21]. A competitive hydrometallurgical technology proposed to leach lead salt from solid waste is methanesulfonic acid [22]. A main drawback of this technology is the necessity to have lead carbonate instead of lead sulfate in solid materials, which usually requires one additional unit operation.…”