Desulfurization and Structural Transformation Behavior of Lead Sulfate in Sodium Hydroxide Molten Salt

Abstract

This paper is devoted to studying the desulfurization and structural transformation behavior of lead sulfate in alkaline medium. The effects of roasting temperature, roasting time, and raw material ratio on the desulfurization and phase transition behavior of lead sulfate in sodium hydroxide molten salt was systematically investigated through a series of experiments and analyses. The results show that lead sulfate is gradually transformed to Pb5O4SO4, α-PbO, β-PbO, and finally to Pb3O4 during roasting in sodium hydroxide molten salt at temperatures of 250°C to 550°C. At the conditions of roasting temperature 450°C, roasting time 40 minutes, molar ratio of lead sulfate to sodium hydroxide 1 : 2.6, lead sulfate can be completely converted to near-pure phase β-PbO powder. This paper provides a simple and efficient method for the recycling of waste lead acid battery, which consists mainly of lead sulfate.