Lead recovery from a typical Brazilian s

Lead recovery from the nonmetallic portion of exhausted lead-acid batteries, also called sludge, was investigated using an electrohydrometallurgical process. Among 13 aqueous solutions studied in solubility tests, only three were chosen for leaching and electrowinning: tetrafluoroboric acid (200 g/L), glycerol (92 g/L) + sodium hydroxide (120 g/L), and sodium potassium tartrate (150 g/L) + sodium hydroxide (150 g/L). Tetrafluoroboric acid exhibited an attractive performance as a leaching electrolyte due to its low cost and reasonable leaching strength. During the electrowinning process with the solution derived from the leaching of a desulfated sludge using this acidic electrolyte, compact, adherent, and highly pure lead deposits were produced at 250 A/m2. Scanning electron micrographs (SEM) of the lead deposits obtained at varying current densities from 250 to 500 A/m2 revealed a significant influence of current density on deposit morphology. This research demonstrates a viable approach for lead recovery from battery sludge, addressing both economic and environmental concerns associated with traditional recovery methods.