Circular economy strategies for mitigating metals shortages in electric vehicle batteries under China's carbon-neutral target.

Concerns over supply risks of critical metals used in electric vehicle (EV) batteries are frequently underscored as impediments to the widespread development of EVs. With the progress to achieve carbon neutrality by 2060 for China, projecting the critical metals demand for EV batteries and formulating strategies, especially circular economy strategies, to mitigate the risks of demand-supply imbalance in response to potential obstacles are necessary. However, the development scale of EVs in the transport sector to achieve China's carbon neutrality is unclear, and it remains uncertain to what extent circular economy strategies might contribute to the reduction of primary raw materials extraction. Consequently, we explore the future quantity of EVs in China required to achieve carbon neutrality and quantify the primary supply security levels of critical metals with the effort of battery cascade utilization, technology substitutions, recycling efficiency improvement, and novel business models, by integrating dynamic material flow analysis and national energy technology model. This study reveals that although 18%-30% of lithium and 20%-41% of cobalt, nickel, and manganese can be supplied to EVs through the reuse and recycling of end-of-life batteries, sustainable circular economy strategies alone are insufficient to obviate critical metals shortages for China's EV development. However, the supplementary capacity offered by second-life EV batteries, which refers to the use of batteries after they have reached the end of their first intended life, may prove adequate for China's prospective novel energy storage applications. The cumulative primary demand for lithium, cobalt, and nickel from 2021 to 2060 would reach 5-7 times, 23-114 times, and 4-19 times the corresponding mineral reserves in China. Substantial reduction of metals supply risks apart from lithium can be achieved by the cobalt-free battery technology developments combined with efficient recycling systems, where secondary supply can satisfy the demand as early as 2054.

Forecasting quantities of critical raw materials in obsolete feature and smart phones in Greece: A path to circular economy.

Mobile phones represent an ever-increasing waste stream due to the increasing ownership and short lifetime. In particular, smartphones are among the most valuable e-waste because of their extremely high content of numerous key metals, specifically in the printed circuit board and magnets. As feature and smart phones contain different key metals at different concentrations, it is important to distinguish between the two phone types to make reliable estimations. This study presents estimations of obsolete mobile phones quantities, generated in Greece in 1995-2035 and the Critical Raw Materials (CRMs) and Precious Metals (PMs) embedded in them, making a differentiation between feature and smart phones. The dynamic material flow analysis is adopted, the lifespan is evaluated by the Weibull distribution and future sales are predicted by the logistic model incorporating phases of growth, saturation and decline. Then, the future wastes are predicted by the Market Supply A model. According to the results, the generation of obsolete smartphones is constantly increasing, while the waste flows of feature phones are declining. Efficient recycling of obsolete phones (1995-2020) can cover the demand for key metals (Au, Pd, Co) in the new smartphones for more than a decade in Greece, while the demand for Ag, Sb, Si, Zn, Be, Ti will be covered for more than 15 years. In 2020-2035 the accumulated amounts of CRMs and PMs, only from the smartphone waste, will be 1292.02 and 14.11 tonnes, respectively. The findings can contribute to the management of a valuable e-waste category closing the loop between resources-products-wastes.

Cobalt in end-of-life products in the EU, where does it end up? - The MaTrace approach.

The use of cobalt has experienced a strong growth in the last decades. Due to its high economic importance and high supply risk, it has been classified as a critical raw material for the EU and other economies. Part of the EU's strategy is intended to secure its availability, through fostering its efficient use and recycling. The latter is affected by factors such as the amount of available end-of-life products, and their collection-to-recycling rate. A novel methodology to analyze the impact of these factors on the cobalt flows in society is the model MaTrace, which can track the fate of materials over time and across products. The MaTrace model was expanded, adapted, and applied to predict the fate of cobalt embedded in finished products in use in the EU, considering the underlying life cycle phases within the technosphere. Eleven scenarios were built, assessing different options in the implementation of relevant EU's policies. The flows were projected for a period of 25 years, starting in 2015. The results of the baseline scenario show that after 25 years, around 8% of the initial stock of cobalt stays in use, 3% is being hoarded by users, 28% has been exported, and 61% has been lost. The main contributors to the losses of the system are the non-selective collection of end-of-life products, and the export of end-of-life products, recycled cobalt and final products. The results of the scenarios show that higher collection-to-recycling rates and lower export could increase up to 50% the cobalt that stays in use.

Evaluating rare-earth constraints on wind power development under China's carbon-neutral target.

China proposed a target to achieve carbon neutrality before 2060. Wind power is crucial for mitigating climate change and achieving carbon neutrality. However, its development depends on the potential constraints of rare-earth elements. Therefore, first projecting the rare-earth demand for wind power equipment in the context of achieving carbon neutrality and identifying potential obstacles are necessary. However, the carbon-neutral pathway for China's power sector is unclear, let alone the corresponding rare-earth demand. Consequently, this study explores a potential cost-effective carbon-neutral pathway for China's power sector and quantifies the demand for rare-earth elements used for producing wind power equipment under different pathways, by integrating dynamic material flow analysis and a national energy technology model. The results showed that the rare-earth supply may be inadequate for wind power development in terms of achieving carbon neutrality in China, especially for dysprosium and terbium. To neutralise the carbon emissions of China's power sector, the cumulative rare-earth demand during 2021-2060 would be 222-434 kt, of which at most 1/3 could potentially be obtained by circular usage from end-of-life wind turbines. However, the existing low secondary recovery rate of rare-earth elements makes the available circular amounts very small. Shifting to a wind power market dominated by direct-drive turbines may increase the cumulative rare-earth demand by up to 34 %. Without material intensity reduction for the wind power technologies, an additional 38 % demand for rare-earth elements will occur, exacerbating the risk of shortage.

Insights into the evolution of cobalt use and implications through dynamic analysis of cobalt flows and stocks and the recycling potential of cobalt from urban mines in China during 2000-2021.

Several countries regard cobalt as a critical material due to its extensive use in clean energy technology and high-tech industries. To comprehensively examine how China's cobalt industry developed and evolved from 2000 to 2021, our study quantified cobalt flows, stocks and the recycling potential of cobalt from China's urban cobalt mines using dynamic material flow analysis. In 2021, China's in-use cobalt stocks for cobalt-containing end products reached 131 kt, of which battery products and superalloys accounted for 83.8% and 8.1%, respectively. The theoretical cumulative recycling potential of cobalt from China's urban cobalt mines reached 204-356 kt between 2000 and 2021 under different scenarios. However, the actual cumulative exploitation of cobalt from urban cobalt mines was 46-80 kt, of which consumer electronics, cemented carbides, and superalloys were the main recycled products. The cumulative exports and imports of cobalt in all commodities reached 558 and 1117 kt, respectively. China exported a large quantity of cobalt chemicals, chemical derivatives and cobalt-containing end products produced from imported cobalt raw materials. China imported 84.7% of the cobalt raw materials consumed domestically, and 32.6% of the domestically produced cobalt-containing end products were exported. Over the entire life cycle of cobalt, cobalt losses totaled 288 kt, with 51.0% of losses coming from refining, and a 73.8% cobalt utilization efficiency was achieved. China recovered 76.7 kt of cobalt, and the recycling rate of cobalt from end-of-life cobalt-containing end products reached 20.0%. The findings can serve as a scientific basis for China's cobalt industry to develop efficiently and economically.

High concentration from resources to market heightens risk for power lithium-ion battery supply chains globally.

Global low-carbon contracts, along with the energy and environmental crises, have encouraged the rapid development of the power battery industry. As the current first choice for power batteries, lithium-ion batteries have overwhelming advantages. However, the explosive growth of the demand for power lithium-ion batteries will likely cause crises such as resource shortages and supply-demand imbalances. This study adopts qualitative and quantitative research methods to comprehensively evaluate the power lithium-ion battery supply and demand risks by analyzing the global material flow of these batteries. The results show that the processes from resources to market of the power lithium-ion battery industry are highly concentrated with growing trends. The proportion of the top three power lithium-ion battery-producing countries grew from 71.79% in 2016 to 92.22% in 2020, increasing by 28%. The top three power lithium-ion battery-demand countries accounted for 83.07% of the demand in 2016 and 88.16% in 2020. The increasing concentration increases the severity of the supply risk. The results also imply that different processes are concentrated within different countries or regions, and the segmentation puts the development of the power lithium-ion battery industry at significant risk. It is urgent to address this situation so that this severe risk can be ameliorated.

Life cycle carbon emissions of different land conversion and woody biomass utilization scenarios in Indonesia.

Wood-based products can contribute to climate change mitigation by prolonging the storage of carbon in the anthroposphere. In Indonesia, however, many wood-based products originate from unsustainable sources due to widespread land-use changes over the past decades. To reconcile economic development and climate policy, a detailed and comprehensive carbon life cycle assessment is needed, covering biospheric and technospheric woody carbon flows and emissions over time. In this study, we combine dynamic material flow analysis, stock modeling, and life cycle assessment to estimate life cycle carbon emissions over time of wood products from different land conversion types in Indonesia on a hectare (ha) basis. Wood production from clear-cut primary forest conversions to oil palm, secondary forest, and timber plantations lead to net carbon emissions between 1206-1282, 436-449, and 629-958 t-CO2-eq/ha, respectively, at the end of the 200-year time horizon (TH). The counter-use scenarios of using non-renewable materials or energy instead of wood-based products for the same set of scenarios while leaving primary forests untouched display 44-57, 59-88, and 5-48% lower global warming potentials, respectively, at the end of the TH. Wood products from forest plantations on restored degraded land (DL_FP), reduced-impact logging (RIL), and improved reduced-impact logging (RIL-C) of primary forest went beyond carbon neutrality, displaying carbon removal potentials of up to around -218, -378, and -739 t-CO2-eq/ha, respectively, by year 200. At the one ha-scale, our results indicate that keeping primary forests intact is the climate-preferable option, even when emissions from the counter-use of non-renewable materials or energy are factored in, except if RIL is performed. Therefore, wood product utilization would only be favorable from a climate perspective in DL_FP or RIL pathways. These results help screen different land conversion policy options and providing information about the climate mitigation potential of wood products in different supply chains.

[Dynamic Material Flow Analysis of Perfluorooctane Sulfonate in China: 1985-2019].

Perfluorooctane sulfonates (PFOS) are regarded as a category of chemicals with persistence, bioaccumulation, and toxicity. Understanding dynamic flows, stocks, and emissions of PFOS on a macro spatial and temporal scale can help provide a scientific basis for their sound management. In this work, a dynamic material flow analysis (d-MFA) model was built to characterize and analyze the cycles of PFOS in mainland China over the period 1985-2019. Flows, stocks, and environmental emissions were calculated and the sensitivity and uncertainty of the results were then analyzed. Results show that domestic production was the primary source of PFOS in China, most of which was flowed to the domestic market in the form of final products, with the remainder exported to international markets; soil and water were the main sinks of PFOS in China, with emissions from the usage stage contributing the largest portion (103 tons in 2019). The number of inflows and outflows were relatively low before 2000, but gradually increased until 2009 when the relevant convention was issued. Since 2005, in-use stocks and emissions of PFOS have grown yearly. In addition, stocks in landfill have been climbing since 1985. End-of-life management was still dominated by traditional methods, such as landfill and incineration, while there was a trend towards green treatments. This study can provide basic data and theoretical support for the sound management of PFOS in China.

Lead release kinetics and film transformation of Pb-MnO2 pre-coated anode in long-term zinc electrowinning.

Lead pollution precaution caused by lead-based anode corrosion is a hot and challenging issue for zinc electrowinning. A novel functional lead-based anode (MnO2 pre-coated anode-MPA) was precisely fabricated and its long-term performances were studied compared with typical Pb-1%Ag anode (TPA). Results indicated that MPA posed excellent effects on synergistic inhibiting lead dissolution and reducing hazardous pollutants generation, and decreasing the lead content of zinc products by 81%. Further, the underlying mechanism of film growth and transformation in structure, composition and crystal phase, the migration and distribution of lead and anode slime during electrolytic, were clarified in-depth. Dynamic material flow analysis confirmed that MPA reduced the entire lead migration amount by over 92% compared with TPA. The compact multilayer structure of the MPA film and self-reparation effects of local structure provided better and persistent protection for the lead matrix, which greatly retarded the high-speed corrosion of lead anode. Compared with α-MnO2 in TPA, the formation and maintenance of γ-MnO2 in MPA accelerated the oxygen evolution reaction and inhibited the anode slime generation. This finding provides new insights in pollution precaution and control by designing and tuning new functional anode in hydrometallurgy process.

End-of-life passenger vehicles recycling decision system in China based on dynamic material flow analysis and life cycle assessment.

China's automobile industry is developing rapidly, but the recycling rate of end-of-life vehicles has been low. In 2018, the recovery rate of end-of-life passenger vehicles was less than 18% of the scrapped amount. Dynamic material flow analysis can predict the amount of end-of-life passenger cars in China in the future, and analyze the flow of materials in recycling system. Life cycle assessment can be used to quantify greenhouse gas emissions. Therefore, this paper integrates these two methods into the model construction of recycling decision system. Meanwhile, sensitivity analysis of the important factors affecting the efficiency of the recovery system is carried out. Finally, the main recovery indexes of the system are predicted under three scenarios: low-speed, medium speed and high-speed development, which are set based on scrap volume, standard recovery rate, proportion of assembly into remanufacturing and carbon tax price. The research results show that in 2018, 656.9 kg/vehicle of iron, 150.2 kg/vehicle of aluminum and 7.9 kg/vehicle of copper are recovered from end-of-life passenger car in China, and the carbon emission during the recovery process is 651.1 kg of CO2eq/vehicle, with a total emission reduction of 3816.1 kgCO2eq/vehicle compared with the original production, and the economic benefit is about 5055.5 yuan/vehicle. The scenario prediction results show that by 2050, from the low-speed development scenario to the high-speed development scenario, the total amount of iron, aluminum and copper recovered rise from 3.96 million tons, 915 thousand tons and 46 thousand tons to 697 thousand tons, 1.61 million tons and 80 thousand tons respectively throughout the year. The carbon emission in the recovery process rise from 4.98 thousand tons to 9.32 million tons. Compared with the original production, the carbon emission reduction increases from 2.21 million tons to 38.3 million tons, the economic benefit increases from 58.9 billion yuan to 118.8 billion yuan, and the comprehensive benefit increases from 57 billion yuan to 111.6 billion yuan.

Modeling the fate and end-of-life phase of engineered nanomaterials in the Japanese construction sector.

To date construction materials that contain engineered nanomaterials (ENMs) are available at the markets, but at the same time very little is known about their environmental fate. Therefore, this study aimed at modeling the potential fate of ENMs by using the example of the Japanese construction sector and by conducting a dynamic material flow analysis. Expert interviews and national reports revealed that about 3920-4660 tons of ENMs are annually used for construction materials in Japan. Nanoscale TiO2, SiO2, Al2O3 and carbon black have already been applied for decades to wall paints, road markings or concrete. The dynamic material flow model indicates that in 2016 about 95% of ENMs, which have been used since their year of market penetration, remained in buildings, whereas only 5% ended up in the Japanese waste management system or were diffusely released into the environment. Considering the current Japanese waste management system, ENMs were predicted to end up in recycled materials (40-47%) or in landfills (36-41%). It was estimated that only a small proportion was used in agriculture (5-7%, as ENM-containing sewage sludges) or was diffusely released into soils, surface waters or the atmosphere (5-19%). The results indicate that ENM release predominantly depend on their specific applications and characteristics. The model also highlights the importance of adequate collection and treatment of ENM-containing wastes. In future, similar dynamic flow models for other countries should consider, inasmuch as available, historical data on ENM production (e.g. like declaration reports that are annually published by relevant public authorities or associations), as such input data is very important regarding data reliability in order to decrease uncertainties and to continuously improve model accuracy. In addition, more environmental monitoring studies that aim at the quantification of ENM release and inadvertent transfer, particularly triggered by waste treatment processes, would be needed in order to validate such models.