Material Recycling: Unearthing Metals from Anthropogenic and Industrial Resources

Direct extraction of Ni(II) from Fe(III), Al(III), Ca(II), Mg(II), and Mn(II) is a bottleneck issue in the hydrometallurgy processes of laterite-nickel ore, spent batteries, and other secondary sources. One of the biggest challenges in achieving direct extraction of Ni(II) is the lack of stable and efficient extractants. Hence, a novel bipyridine extractant MSL211 was designed and synthesized in this paper. With its strong steric resistance and electrostatic interaction, MSL211 can form a stable eight-membered chelating ring with Ni(II), thereby having a high bonding ability toward Ni(II). Therefore, based on the high bonding ability of MSL211 toward Ni(II) and the low extraction capacity of DNNSA for Fe(III), an efficient synergistic extraction system of DNNSA-MSL211 was proposed. The synergistic extraction system of DNNSA-MSL211 realizes direct extraction of Ni(II) from Fe(III), Al(III), Ca(II), Mg(II), and Mn(II) without neutralization, precipitation, and solid/liquid separation processes, which are inevitable but problematic processes in the current hydrometallurgy processes for removing Fe(III), Al(III), and Mn(II). The effects of the molar ratios of DNNSA:MSL211, shaking time, temperature, O/A ratios, and equilibrium pH on the extraction behavior of Ni(II) were investigated. Under optimum conditions, the extraction efficiency of Ni(II) was as high as 97.62%, and the separation coefficient of Ni(II) over all impurities was greater than 400. To elucidate the mechanism of the high selectivity of DNNSA-MSL211 toward Ni(II), DFT calculations were carried out to calculate the binding energy (ΔE) and Gibbs free energy (ΔG(ext)) of the extraction process. Furthermore, this paper investigated the entire ″extraction-stripping″ process, demonstrating that the synergistic extraction system of DNNSA-MSL211 avoids neutralization, precipitation, and solid/liquid separation processes, minimizes hazardous waste generation, and shortens process flow while meeting the objectives of sustainable and clean production.

Section: Introductionmentioning

confidence: 99%

Direct Extraction of Ni(II) from Acidic Polymetallic Sulfate Media with a Novel Synergistic Extraction System of DNNSA-MSL211

Zheng

Cao

et al. 2023

“…6 The leaching process is usually performed in nonpressurized hot water using acid as the leachant in the presence of a reductant (e.g., H 2 O 2 , NaHSO 3 , or Na 2 S 2 O 3 ). 7 Until now, various acids have been applied as the leachant, including inorganic acids (e.g., hydrochloric acid, sulfuric acid, and nitric acid) and organic acids (e.g., citric acid, lactic acid, glycine, and succinic acid). 8−10 In the presence of reductants, completed leaching can be achieved by either inorganic or organic acids, but because of less impact on the environment, organic acids are gradually replacing inorganic acids.…”

Section: ■ Introductionmentioning

confidence: 99%

Excellent Performance of Glycine in Isolating Mn during Hydrothermal Leaching of LiMn₂O₄ Cathode Materials

Zheng,

Hirama,

Nakajima

et al. 2023

In this study, hydrothermal leaching of spent LiCo x Ni y Mn 1−x−y O 2 (NMC) and commercial LiMn 2 O 4 (LMO) cathode materials was conducted by applying glycine as a leaching agent. During the hydrothermal leaching of spent NMC, the effects of reaction temperature, reaction time, glycine concentration, and pulp density on the leaching efficiencies of Li, Co, Ni, and Mn were investigated. With the increase in reaction temperature and time, the leaching efficiencies of Co, Ni, and Mn significantly increased, but even at 200 °C for 15 min, the leaching efficiency of Mn was as low as 16%. The order of the reaction rate was confirmed to be Mn < Co < Ni < Li. Compared with Li, Co, and Ni, the leaching performance of Mn was much poorer, but this special property makes it possible for glycine to isolate Mn directly from the LMO cathode material. During the hydrothermal leaching of the commercial LMO cathode material with glycine, the leaching efficiency of Li significantly increased with reaction temperature and time and was much higher than that of Mn under the same condition. A kinetic study using a shrinking unreacted core model was conducted. The results revealed that the diffusion within the product layer was the rate-limiting step for leaching Li and Mn. Based on the determined reaction rates, the activation energy of Li leaching was calculated to be 57.1 kJ/mol within 0−15 min and 69.6 kJ/ mol within 15−90 min, respectively, while that of Mn leaching was 86.7 kJ/mol. At 200 °C for 120 min, the leaching efficiencies of Li and Mn achieved 99.5 and 7.6%, respectively, which means that 92.4% of Mn was successfully isolated and kept in the solid residue. After calcinating at 600 °C for 1 h, the final product was obtained and identified to be Mn 2 O 3 with a purity of 99.0%. This was the first report on the excellent performance of glycine in isolating Mn and achieving Mn isolation in a single-step hydrothermal leaching process of LMO cathode materials with such a high recovery and product purity.

“…31 As Co and Mn in batteries are hardly soluble, a reductant such as H 2 O 2 or NaHSO 3 is added to enhance the recovery rate of the metals. 32 Environmentally speaking, currently it remains unclear which hydrometallurgical recycling methods are preferred to establish a true sustainable battery-recycling industry. To close this gap and provide environmentally sustainable circular approaches, this study quantifies, analyzes, and compares the environmental impacts arising during the hydrometallurgical recycling of the LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode.…”

Section: ■ Introductionmentioning

confidence: 99%

Environmental Impact Assessment of LiNi_1/3Mn_1/3Co_1/3O₂ Hydrometallurgical Cathode Recycling from Spent Lithium-Ion Batteries

Iturrondobeitia

Vallejo

Berroci

et al. 2022

The global demand for lithium-ion batteries (LIBs) has witnessed an unprecedented increase during the last decade and is expected to do so in the future. Although the service life of batteries could be expanded using Circular Economy approaches such as repair or remanufacture, batteries will inevitably become a huge waste stream as electric vehicles gain popularity. Battery recycling reintroduces end-of-life materials back into the economic cycle and prevents landfill scenarios. The reclamation of materials from spent batteries in general, and cathodes in particular, reduces the pressure over finite critical raw materials such as cobalt, nickel, lithium, or manganese and avoids severe heavy metal contamination issues associated with battery disposal. To establish a sustainable battery-recycling industry, the environmental impact assessment of cathode-recycling approaches is urgently needed. Accordingly, a life-cycle assessment methodology is applied to quantify and compare the environmental impacts of nine hydrometallurgical laboratory-scale LIB cathode-recycling processes in 18 impact indicators such as global warming potential. The LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode is selected given its predominant market share among electric vehicles. Hydrometallurgical recycling approaches based on inorganic acid-leaching (hydrochloric, sulfuric, and phosphoric acids), inorganic alkali-leaching (ammonia/sodium sulfite), organic leachates (citric, formic, or lactic acids), and bioleaching processes are analyzed. Scaling up the recycling to 1 kg cathode, global warming values from 25.1 to 95.2 kg•CO 2 -equiv per 1 kg of recycled cathode are obtained. The processes based on HCl and H 2 SO 4 /H 2 O 2 and the autotrophic bio-leaching process are preferred to lower greenhouse gas emissions and toxicity-and resource-related potential impacts. The choice of chemicals, the energy consumption, and more importantly, material efficiency emerge as the cornerstones to achieve environmentally sustainable processes. A sensitivity analysis demonstrates the potential to reduce the impacts by transitioning to a renewable energy mix, reaching a global warming value of 5.01 kg•CO 2 -equiv•kg cathode −1 . These results provide guidance toward further process optimization through eco-design approaches, securing the long-term sustainability of LIBs.