Solvent Extraction for Separation of 99.9% Pure Cobalt and Recovery of Li, Ni, Fe, Cu, Al from Spent LIBs

Abstract

In this work, hydrometallurgical recycling of metals from high-cobalt-content spent lithium-ion batteries (LIBs) from laptops was studied using precipitation and solvent extraction as alternative purification processes. Large amounts of cobalt (58% by weight), along with nickel (6.2%), manganese (3.06%) and lithium (6.09%) are present in LiCoO2 and Li2CoMn3O8 as prominent Co-rich phases of the electrode material. The pregnant leach solution (PLS) that was generated by leaching in the presence of 10% H2O2 using 50 g/L pulp density at 80 °C for 4 h contained 27.4 g/L Co, 3.21 g/L Ni, 1.59 g/L Mn and 3.60 g/L Li. The PLS was subjected to precipitation at various pH using 2 M NaOH but the purification performance was poor. To improve the separation of Mn and other impurities and in order to avoid the loss of cobalt and nickel, separation studies were carried out using a solvent extraction technique using di-(2-ethylhexyl) phosphoric acid (D2EHPA) and bis-(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272). Overall, this study examines the fundamentals of separating and synthesizing 99.9% pure Co sulfate from leach liquor of spent laptop LIBs with remarkably high cobalt content.

A Review of Recovering Lithium and Cobalt from Spent LiCoO2 Lithium‐Ion Batteries Cathode

“…Meshram proposed the extraction equilibria of metals with di-(2-ethylhexyl) phosphoric acid (D2EHPA) and Cyanex 272, as depicted in Figure 3. [81] Previous literature also shows similar equilibria behavior. [82][83][84][85][86] Jian et al, recovered Co and Li elements by adding P507 as an extractant, which contributes to reaching a high Co extraction rate, while the Li extraction rate is very low.…”

“…Meshram proposed the extraction equilibria of metals with di‐(2‐ethylhexyl) phosphoric acid (D2EHPA) and Cyanex 272, as depicted in Figure 3 [81] . Previous literature also shows similar equilibria behavior [82–86] .…”

“…Ren [19] Figure 3. The extraction equilibria of metal using (a) Cyanex 272 and (b) D2EHPA.. [81] Figure 4. Oxalic acid dissolution behavior on spent LiCoO 2 cathode.…”

Design of Recycling Processes for NCA-Type Li-Ion Batteries from Electric Vehicles toward the Circular Economy

“…15 Literature reports the use of reducing agents such as H 2 O 2 and sodium bisulfite (NaHSO 3 ) to convert Co(III) into Co(II). However, it represents a considerable cost impact in the leaching step as reported by Verma et al 16 Then, separation and purification steps are 17 Precipitation has demonstrated an important technique for Al removal, and the overlap of pH range for different metals makes the attempt of separation for each pure metal ineffective. 17−20 The present study aimed to develop the recycling process of NCA-type Li-ion batteries contributing to the scarce literature regarding this spent battery recycling.…”

“…However, it represents a considerable cost impact in the leaching step as reported by Verma et al Then, separation and purification steps are necessary to obtain different products from the leach solution. Solvent extraction has been evaluated, as reported by Meshram et al, using di­(2-ethylhexyl)­phosphoric acid (D2EHPA) and bis-(2,4,4-trimethylpentyl)­phosphinic acid (Cyanex 272) to separate Co from Li, Ni, and Mn after Al precipitation reaching 99% of Co purity . Precipitation has demonstrated an important technique for Al removal, and the overlap of pH range for different metals makes the attempt of separation for each pure metal ineffective. − …”