Sustainable extraction and purification of REE and other metals from unsorted battery waste

• Rare earth elements and metals leaching from unsorted battery waste. • REE recovery by selective precipitation. • Separation of zinc, manganese, cadmium, nickel, and cobalt by solvent extraction. • Zinc and cadmium recovery by electrodeposition. • Manganese, nickel and cobalt recovery by selective precipitation. Recycling the metals in household batteries usually requires a sorting stage, as the batteries are processed according to their chemistry. The aim of the present work was to define a technological process for extracting and recovering rare earth elements (REE) and other metals (Zn, Mn, Cd, Co, Ni) from unsorted battery waste. Two consecutive non-selective leaching steps using 1.34 M H 2 SO 4 and 0.45 g Na 2 S 2 O 5 /g powder with 100 g/L battery powder resulted in the solubilization of 84 % REE, 100 % Fe, 100 % Zn, 100 % Cd, 100 % Mn, 100 % Ni and 97 % Co. The REE is then recovered by precipitating double sulfates of REE, followed by a step of re-precipitating the REE as oxalate and calcining it to form a rare earth oxide concentrate (95 % purity). Iron is then removed by hydroxide precipitation at pH 4, while zinc is separated by solvent extraction (30 % Cyanex 272 + 5 % TBP, O/A ratio = 0.4, pH 2.5–2.8) and electrodeposited (99.96 % purity) at pH 2. Next, Cd and Mn are separated from the other metals by solvent extraction (30 % D2EHPA + 5 % TBP, O/A ratio = 2, pH 2.7–2.9) and selectively precipitated as CdS (83 % purity) at pH 7–8 and MnCO 3 at pH 9.5–10.5, which is then calcined to produce MnO (96 % purity). Cobalt is then separated from nickel by solvent extraction (10 % Cyanex 272 + 5 % TBP, O/A ratio = 1, pH 5.7–6.5) and both metals are recovered by oxalate formation and subsequently calcined to form cobalt oxide (79 % purity) and nickel oxide (97 % purity).