Temporal and Spatial Characteristic of Iron In-Use Stocks in Henan Province, China

With the acceleration of urbanization and industrialization in China, iron in-use stocks (IIUS) are accumulating rapidly. IIUS is potential reservoirs accessible for urban mining and a major source of future renewable energy. So this study used Henan Province as a case to assess IIUS and its spatial distribution at the provincial level in China. In this study, a bottom-up model was used to estimate the temporal characteristics of IIUS, and analyzed the prefecture-level spatial distribution of IIUS in 2021 based on the spatial autocorrelation model. Meanwhile, this study also explored the decoupling between IIUS and economic development using the constructed Tapio-LMDI model and identified the factors affecting the decoupling relationship. The results showed that, 1) Henan Province’s total IIUS reached 474.51 Mt in 2022, increasing by 7.89 times from 2000. The largest contributor of IIUS was building sector, which accounted for 66.89% of the total in 2022. 2) At prefecture-level cities, the density of IIUS varied from 1055.35 to 8855.35 t/km2 in 2021, indicating a signification imbalance in spatial distribution. 3) Moran’ I index for IIUS in Henan Province was 0.47 and the Z-value was 2.75 (P < 0.001), showing a significant spatial positive correlation. 4) There is a Weak-decoupling relationship between IIUS and economy, and technology factor is the main factor to promote decoupling. The government needs to improve the technology to realize the decoupling of IIUS.