Work

Efficient Desulfurizer Recycling during Spent Lead–Acid Batteries Paste Disposal by Zero‐Carbon Precursor Hypothermic Smelting

Year: 2024

Type: article

Abstract: Recycling of spent lead‐acid batteries (LABs) is extremely urgent in view of environmental protection and resources reuse. The current challenge is to reduce high consumption of chemical reagents. Herein, a closed‐loop spent LABs paste (SLBP) recovery strategy is demonstrated through Na2MoO4 consumption‐regeneration‐reuse. Experimental and DFT calculations verify that MoO42− competes Pb/Ca ions and weakens the metal‐oxygen bond of PbSO4/CaSO4.2H2O in SLBP, facilitating PbMoO4/CaMoO4 formation and 99.13 wt% of SO42− elimination. Pb of 99.97 wt% is obtained as zero‐carbon precursors (PbO2 and PbMoO4) by green leaching coupled with re‐crystallization. The regeneration of Na2MoO4 is realized at 600 ℃ using LABs polypropylene shells and NaOH as reagents. Compared with the traditional smelting technologies, the temperature is reduced from ＞1000 to 600 °C. The extraction of Na2MoO4 require only water, and satisfactory re‐used desulfurization efficiency (98.67 wt%) is achieved. For the residual Na2MoO4 after first SLBP desulfurization, the desulfurization efficiency remains above 97.36 wt% after adding fresh reagents for two running cycles. The new principle enables the reuse of 99.83 wt% of Na2MoO4 and the recycling of 95.27 wt% of Pb without generating wastewater and slags. The techno‐economic analysis indicates this strategy is efficient, economical, and environmentally‐friendly.

Source: Advanced Science

DOI: 10.1002/advs.202405168