Dataset: Task-Specific TEAB–Lactic Acid–NH₃(OH)Cl Solvent for Selective Co/Li Recovery from LiCoO₂ Black Mass
Description
This dataset tests the hypothesis that a task-specific TEAB–lactic acid–NH₃(OH)Cl ternary solvent can be deliberately designed as a structured, redox-active leaching medium for LiCoO₂-derived black mass, rather than selected only by trial-and-error extraction performance. The central idea is that TEAB provides the ionic scaffold, lactic acid provides proton activity and oxygen-donor coordination, and NH₃(OH)Cl supplies in situ reductive functionality needed to convert poorly soluble lattice-derived Co(III) into soluble Co(II), thereby enabling efficient and selective recovery of cobalt and lithium. The data include feed characterization, formulation screening, spectroscopic solvent characterization, viscosity measurements, leaching experiments, cobalt oxidation-state analysis, kinetic fitting, response-surface modeling, product-phase verification, elemental mass balance, and regeneration testing. The black mass was first confirmed to be cobalt-rich by ICP analysis (64.318 ± 0.379 wt.% Co; 5.130 ± 0.025 wt.% Li), after which multiple solvent compositions were prepared and screened through time-resolved liquid formation, UV–Vis baseline behavior, FTIR, Raman, NMR, and rheology. The selected 1:1:1 solvent was then used for leaching under different temperatures, times, and solid loadings. Metal concentrations were measured by ICP-OES using a sampling-corrected cumulative mass-balance approach, cobalt speciation was assessed by matrix-matched UV–Vis, and recovered solids were identified by XRD. Regeneration data were collected across seven recycle runs, including recovery, viscosity, conductivity, make-up demand, and residual solute trends. The dataset shows that the balanced 1:1:1 TEAB–LA–NH₃(OH)Cl formulation gave the best overall compromise between liquid homogeneity, processable viscosity, and chemical functionality. Matrix-matched UV–Vis showed that dissolved cobalt in the leachate was predominantly Co(II) (99.4%) with only 0.6% Co(III), confirming that the solvent behaves as a genuinely reductive medium and not simply an acidic one. Under the most practical operating condition (90 °C, 90 min, 33.3 g L⁻¹), the solvent achieved 97.80 ± 0.14% Li and 99.83 ± 0.03% Co extraction. XRD confirmed downstream recovery of crystalline Li₂CO₃ and CoC₂O₄·2H₂O, while regeneration tests showed sustained cobalt recovery of 99.24–99.87% over seven cycles. Keywords LiCoO₂ black mass; lithium-ion battery recycling; deep eutectic solvent; ternary solvent; tetraethylammonium bromide; lactic acid; hydroxylammonium chloride; reductive leaching; cobalt recovery; lithium recovery; response surface methodology; kinetic modeling; solvent regeneration; hydrometallurgy.
Files
Steps to reproduce
The dataset was generated through a structure–property–function workflow designed to identify and validate a task-specific TEAB–lactic acid–NH₃(OH)Cl ternary solvent for the reductive dissolution of LiCoO₂-derived black mass. First, the black mass feed was produced by an integrated mechanical and interfacial material recovery route and verified by ICP to confirm that cobalt and lithium were the dominant target metals. The solvent was then prepared from tetraethylammonium bromide (TEAB, ≥99%), lactic acid (≥85%), and hydroxylammonium chloride (≥99%) using several balanced, acid-rich, TEAB-rich, reductant-rich, binary, and water-modified formulations. Each formulation was made as a 10 g batch in closed glass vessels and heated at 90 °C for 60 min under magnetic stirring. Liquid formation was monitored at 15, 30, 50, and 60 min by recording liquefaction, residual solids, wall deposition, and phase clarity. Formulations that reached stable single-phase or near-homogeneous liquid states were characterized by UV–Vis for optical stability, FTIR for hydrogen-bond restructuring, Raman and ¹H/¹³C NMR for supramolecular organization, and viscosity measurements at 25.0 ± 0.1 °C and 80.0 ± 0.1 °C in triplicate. Based on these combined results, the 1:1:1 TEAB–LA–NH₃(OH)Cl formulation was selected as the working solvent. Leaching experiments were then performed with this solvent at 25, 33.3, and 50 g L⁻¹ solid loading and 50–90 °C. 2 mL aliquots were withdrawn every 15 min and analyzed by ICP-OES. Clear aliquots were filtered, acidified, and diluted in about 1% HNO₃, while semi-solid aliquots underwent total-recoverable acid preparation. Because repeated sampling removed dissolved metals from the reactor, Li and Co recoveries were calculated using a sampling-corrected cumulative mass-balance method. To confirm reductive dissolution, cobalt oxidation state in the leachate was measured by matrix-matched UV–Vis. The cobalt-bearing leachate was diluted 1:20 with blank solvent, scanned from 200–900 nm in 1 cm quartz cuvettes, and calibrated with CoCl₂·6H₂O standards prepared in the same solvent matrix. A 3% H₂O₂ test was used to probe residual Co(III). Extraction data were then fitted with PFO, PSO, and Avrami kinetic models, and process optimization was carried out by response surface methodology using second-order polynomial models. Recovered products and residues were identified by XRD, and solvent reuse was evaluated over seven regeneration cycles by monitoring recovery, recovered solvent mass, make-up demand, viscosity, conductivity, and residual solutes. These datasets and modeling files allow reproduction of the experimental workflow, calculations, and interpretation pathway.
Institutions
- Shanxi UniversityShanxi, Taiyuan