Improving aluminium resource efficiency in China: Based upon material flow analysis and entropy analysis

Aluminium is one widely used metal that plays an important role in China's industrial and economic development. The life cycles of aluminium products involve high energy inputs, intensive material consumption and heavy environmental emissions. China has released its ambitious climate change targets, namely reaching carbon peak in 2030 and achieving carbon neutrality in 2060. It is therefore urgent to take appropriate actions to reduce the overall greenhouse gas emissions from aluminium production and increase resource efficiency along the entire aluminium life cycle. Under such circumstances, this study aims to explore China's aluminium recycling potential through dynamic material flow analysis for the period of 2000–2019, covering its whole life cycle and including relevant international trade activities. An entropy analysis method is also applied to identify optimal pathways to improve aluminum resource efficiency and circularity. Results indicate that China has experienced fast growth of aluminum production and consumption during the last two decades, with its output of primary aluminium increasing from 4.18 Mt in 2000 to 35.11 Mt in 2019 and its aluminium consumption increasing from 2.99 Mt in 2000 to 32.5 Mt in 2019. Such rapid growth has resulted in significant environmental impacts. For instance, environmental loss of aluminium at the production stage accounted for 46% of the total loss throughout its entire life cycle in 2000, while such a rate increased to 69% in 2019. As such, entropy analysis results reflect that at the stage of waste management, the relative entropy of aluminium is rising, which indicates that any pollutants discharged into the environment will cause significant damage. Scenarios analysis results further help to identify the optimal pathway of aluminium metabolism system. Finally, several policy recommendations are proposed to improve the overall aluminium resource efficiency.