Recovery of valuable metals from the hydrochloric leaching solution of reduction smelted metallic alloys from spent lithium‐ion batteries

Abstract

BACKGOUND The recycling of valuable metals from spent lithium‐ion batteries (LIBs) has attracted much attention. This work investigated the recovery of cobalt (Co), nickel (Ni), copper (Cu), iron (Fe) and manganese (Mn) from metallic alloys generated from the reduction smelting of spent LIBs by a hydrometallurgical process. RESULTS The complete leaching conditions for metals from the alloys were optimized as: 2.0 mol L–1 hydrochloric acid (HCl), 5% (v/v) hydrogen peroxide (H2O2) with 30 g L–1 pulp density at 60 °C within 150 min. Metal ions such as Co(II), Ni(II), Cu(II), Fe(III), Mn(II) and silicon [Si(IV)] from HCl leachate were separated sequentially in four steps using solvent extraction and oxidative precipitation. First, Fe(III) was completely extracted over others using 0.5 mol L–1 Di‐(2‐Ethyl Hexyl) phosphoric acid (D2EHPA). Second, Cu(II) from the Fe(III)‐free raffinate was selectively extracted using 0.25 mol L–1 Cyanex301. Fe(III) and Cu(II) were quantitatively stripped from their loaded phases using 50% (v/v) aqua regia. Third, Co(II) from the Fe(III)‐ and Cu(II)‐free raffinate was selectively extracted over Ni(II), Mn(II) and Si(IV) with 0.25 mol L–1 ALi‐SCN and stripped with 10% (v/v) ammonia (NH3). Finally, Mn(II) from the raffinate containing Ni(II) and Si(IV) was separated at pH 3 by oxidative precipitation of MnO2 after adding 10% (v/v) sodium hypochlorite (NaClO). Mass balance analysis of the whole process indicated that the recovery and purity percentage of the metal ions were >99.9%. CONCLUSION With its effective and selective performance, the application of this process to real‐life recovery of valuable metals from spent LIBs can be considered. © 2021 Society of Chemical Industry (SCI).

Use of ferric salt solutions as leaching agents of Co, Ni, Cu, Fe, and Mn from metallic alloys of spent lithium-ion batteries and separation of iron from the leaching solution

“…Although the stripping of Fe(III) from the loaded D2EHPA can be improved by using reducing agents such as SO2, H2SO3 and Na2SO3, multi-stage stripping is required for the complete stripping of Fe(III) [27]. In our previous studies, the complete stripping of Fe(III) from the loaded D2EHPA was obtained using aqua regia solution and the effect of aqua regia on the chemical structure of D2EHPA after the stripping was found to be insignificant [18]. Hence, in this work, aqua regia solution was employed for the stripping of Fe(III) from the loaded phase.…”

“…(aq) (7) Our previous studies showed that the complete leaching of metals from the alloys by acidic solutions required 2.0 mol/L HCl or H2SO4, 10% (v/v) H2O2 at 60 o C with 150 or 240 min reaction time [17,18]. Compared with the leaching of metals by acid solutions containing H2O2 as an oxidizing agent, either single Fe2(SO4)3 or FeCl3 solution showed some advantages in the recovery of metals such as: (1) the role of ferric salts as an oxidizing agent which would improve the process economics, (2) fast reaction kinetics, (3) low energy consumption due to leaching reactions at room temperatures, and (4) a decrease in the consumption of acids.…”

“…In our previous studies, the selective separation of Fe(III) over Co(II), Ni(II), Cu(II), Mn(II) from the sulfate and chloride leaching solutions was obtained by solvent extraction with D2EHPA [17,18]. Therefore, D2EHPA in kerosene was employed for the removal of Fe(II) and Fe(III) ions from the leaching solutions by ferric salt solutions.…”

“…In our previous works, hydrometallurgical processes for the recovery of these metal ions from the metallic alloys were reported. Those processes consisted of leaching with either HCl or H2SO4 solution in presence of oxidizing agent followed by separation steps such as solvent extraction and oxidative precipitation [17,18]. However, the use of oxidizing agents at high concentration (10% (v/v) H2O2) in strong acid medium (2.0 mol/L acids) was required in the proposed processes.…”

Separation of Ni(II), Co(II), Mn(II), and Si(IV) from Synthetic Sulfate and Chloride Solutions by Ion Exchange

“…In our previous work, the combined processes for the recovery of valuable metals from sulfate and chloride solution from spent LIBs were reported 4,5) . Smelting reduction of spent LIBs at high-temperature results in metallic alloys containing Co, Ni, Cu, Fe, and Mn.…”