Abstract:Rare earth magnetic materials (REMM) experience a sustained increase in market demand in the fields of new energy, renewable energy generation, and environmental protection industries. As the world's leading producer of REMM, China will continue to meet the high global demand for rare earth resources. However, the production process of rare earth products often comes with severe environmental pollution issues. Therefore, conducting an environmental impact assessment on REMM and formulating a coordinated pathway for energy saving and carbon reduction play a significant role in promoting the green and low-carbon development of the rare earth industry. The life cycle assessment (LCA) and environmental management tool were utilized to establish a multi-objective scenario-based model for analyzing carbon emissions and energy-saving carbon reduction in REMM. This model used “the manufacture of one kilogram of REMM product” as the functional unit, with system boundaries covering five unit processes: rare earth ore mining and selection, rare earth ore refining, rare earth extraction and separation, rare earth metal purification, and REMM manufacturing, i.e., “cradle to gate.” Given the unique co-occurrence characteristics of rare earth products, a mass-based proportional allocation method to address resource allocation issues was adopted. By conducting a detailed calculation of the energy consumption and carbon footprint of representative REMM products in China, the current status of the industry in terms of energy consumption and greenhouse gas emissions were revealed. Further, through exploring various strategies such as the application of advanced manufacturing technologies, diversification of mineral resource sources, popularization of remanufacturing technologies, and the green transformation of power supply structures, the study aimed to explore feasible paths for achieving energy conservation, emission reduction, and low-carbon development in China's REMM industry. To ensure the accuracy and representativeness of the data, information from typical enterprises in major rare earth-producing regions in China were collected, including Inner Mongolia, Jiangxi, Anhui, and Sichuan. Data on raw material production and energy supply in the upstream supply chain were sourced from the Beijing University of Technology LCA basic database, the Ecoinvent database, and relevant literature, which were supplemented and improved as necessary. The results indicate that under single-factor analysis, technological progress has a significant positive effect on environmental impact, with REO-N4 achieving a 19.20% reduction in carbon emissions and a 11.26% reduction in energy consumption, followed by REO-N3, which achieved reductions of 7.42% and 8.75%, respectively. The combined application of REO-U2 can reduce global warming potential (GWP) and energy consumption (EC) by 29.15% and 23.02%, respectively. Adjustments in mineral sources has a minor impact, with the average GWP per unit of REMM being 30.1 kg CO2 eq and the average EC being 75.8 MJ. In 2022, China's mineral source ratio meets optimal interval standards, with the unit GWP being 13.62% lower than the average level and the unit EC being 9.75% higher. The application of remanufacturing technology achieves significant reductions in GWP and EC. When REM-SR and REM-BR are used together, the best energy-saving and carbon-reduction effects are achieved for neodymium-iron-boron, with GWP and EC reduced by 70.97% and 69.31%, respectively. Under the optimized power structures, the GWP per unit of REMM changes consistently with the GWP per unit of electricity, decreasing from 26.03 kg CO2 eq in 2022 to 18.36 kg CO2 eq in 2050, a cumulative reduction of 29.46%. In multi-factor scenario analysis, both combined scenarios one (S1) and two (S2) can achieve peak carbon targets at medium and high promotion efficiencies, but the REMM industry will still generate approximately 5.37 million tons of carbon emissions by 2050. Considering various factors and the effects of energy saving and carbon reduction, the study recommends choosing the medium promotion efficiency mode of scenarios two (S2). Although its carbon emissions is 4.48% higher annually compared to scenarios one (S1), scenarios two (S2) has a higher degree of technological maturity and the capability for large-scale application. Additionally, while there is no significant downward trend in industry energy consumption under this mode, there is a plateau period of about 20 years, which is significant for the green and healthy development of the industry. To achieve the carbon neutrality goal by 2060, it is necessary to apply CCUS technology and other measures to offset residual carbon emissions. The green and low-carbon transformation of the REMM industry requires efforts from multiple fronts. The application of advanced technologies, adjustment of mineral sources, promotion of remanufacturing, and optimization of power structures are key measures to achieve the industry's energy-saving, pollution reduction, and carbon reduction goals. In the future, there should be continued strengthening of technological innovation and policy support to promote more sustainable development in the REMM industry.