Preparation of thermally sensitive ceramics by co-precipitation of mixed acid-soaked spent LIBs: Experimental methods, structure and mechanism

The recovery of valuable metals from spent LIBs is essential for environmental protection and economic development. This study used a green and mild organic mixed acid to leach valuable metals from spent LIBs to prepare thermally sensitive ceramics. The effects of acid concentration, temperature, time, and S/L on the leaching efficiency were investigated during the leaching process. The effects of the elemental molar ratio on the ceramic properties were also explored. The results revealed that there was an optimum leaching efficiency at 1.25 M citric acid, 0.5 M ascorbic acid, 70 min, 353 K, 50 g/L, and 500 r/min. The characterization of the substances before and after leaching by XRD and SEM confirmed the effective leaching of valuable metals by the mixed acids. FT-IR, Raman, and UV-Vis analyses further verified that the mixed acids leached valuable metals through the synergistic effect of acidity and reduction. The leaching kinetics study revealed that the leaching process conforms to the leaching mechanism of the Arvami equation. Thermal ceramic materials were prepared by co-precipitation of mixed acid leaching spent LIBs. Mn1.2CoxNi1.8-xO4 (x = 1.5) ceramics have excellent crystalline shapes and densification. The R-T curves confirmed that Mn1.2CoxNi1.8-xO4 has significant thermally sensitive ceramic properties. This study is the first to use spent LIBs with valuable metals for the preparation of thermal ceramics, which provides a new way to recycle and apply valuable metals in spent LIBs. •Efficient leaching of valuable metals from spent LIBs using organic mixed acids to reduce secondary pollution.•An environmentally friendly closed-loop process for spent LIBs is proposed.•The possible leaching mechanisms of citric acid and ascorbic acid for valuable metals were studied.•The leaching kinetics show that the leaching model of organic mixed acids is consistent with the Avrami equation model.•Valuable metals in spent LIBs are used in thermally sensitive ceramic materials, providing a new way to recycle and apply valuable metals in spent LIBs.