In order to obtain accurate data about university students’ awareness of retired mobile phones in China, a survey was conducted in both 2012 and 2020. There were 1011 respondents in 2012 and 1830 in 2020 that completed the questionnaire, respectively, aged 18–30 years old. This work proposes the following conclusions: lifetime is reduced from 1.95 years in 2012 to 1.92 years in 2020, with a standard deviation of 1.12 in 2012 and 0.99 in 2020; broken is the most common reason for replacements, but there are also many replacements caused by poor function, poor model, or stolen, while more than half of the retired mobile phones are stockpiled, instead of being donated or sold; voucher or cash incentives are the most efficient, while environmental and charitable incentives are also efficient; when participating in take-back services with mobile phones manufactured in the last five years, or even with broken ones, the expectant amount of cash refund is 20–300 CNY in 2012 and 20–500 CNY in 2020; most results are consistent with previous research, while the distinctions are important and helpful; policy implications are proposed to improve sustainable WEEE management systems.

The industrial motor systems account for 45% of global electricity consumption. A life cycle model is established to quantify the potential environmental benefits of typical adjustable permanent magnet drives (APMDs, 1250 kW) versus variable frequency drives (VFDs) in China. The model covers mining of metals, manufacturing, operation, and recycling phases of APMDs, incorporating empirical data from China’s 3232 coal-fired units. Four scenarios are set up: business-as-usual, moderate, aggressive, and full-retrofit. Key findings demonstrate that APMDs reduce operational energy consumption by 94.5% compared to VFDs through significantly declining frequency conversion losses and cooling requirements. The life cycle carbon emissions of APMDs (29.7 tonnes CO₂_eq) represent merely 5% of VFDs emissions (570 tonnes CO₂_eq), achieving a 95% reduction. Within APMDs’ footprint, recycling contributes a 45% emission offset (−13.3 tonnes CO₂-eq), while operational efficiency drives the majority of the reduction. Sensitivity analysis identifies electricity emission factors, NdFeB production emissions, and metal recycling rates as primary sensitivity drivers (sensitivity index ST = 0.80). Scenario simulations confirm that the aggressive retrofit strategy (covering high- and moderate-potential units) could reduce annual GHG emissions of 3.12 million tonnes CO₂_eq., with corresponding 89% decreases in particulate matter (PM). This research demonstrates that APMDs are an effective pathway for the low-carbon transition in coal power systems. Their large-scale implementation can potentially necessitate breakthroughs in tiered retrofit policies, thereby providing crucial technological support for industrial carbon neutrality.