## 5 Conclusions  
This study developed an integrated spatio-temporal characterization framework to provide a scientific basis for regional resource recycling strategies in Henan Province, combining the bottom-up method, the spatial autocorrelation model, Tapio-LMDI, and the stock-driven model. Several conclusions are as follows. 1. Henan Province's SIUS increased from 53.41 Mt in 2000 to 499.35 Mt in 2023, with per capita SIUS rising from 0.56 t/cap to 5.09 t/cap, an increase of 9.04 times. Projections indicate that SIUS will reach 802.99 Mt by 2060, with the annual growth rate declining from 10% in 2023 to 5% by 2060, suggesting that SIUS is nearing saturation. This reflects a significant transformation in the iron and steel industry in Henan Province, marking a shift from primary steel production to scrap-based steelmaking. The buildings sector will remain the primary contributor, accounting for 65% of total SIUS by 2060, highlighting its dominant role in steel stock dynamics. 2. At prefecture-level cities, while category distribution patterns are relatively consistent across 18 cities, stock density varies significantly, between 1055.35 and 8855.35 t/km\({}^{2}\), revealing signification spatial heterogeneity. Spatial autocorrelation analysis highlights significant clustering of per capita SIUS in Jiaozuo and Jiyuan, necessitating the establishment of regional scrap recycling hubs in these areas to optimize collection efficiency. 3. The Tapio model shows a persistent weak decoupling between SIUS and economic growth, with the correlation gradually weakening. Through the decomposition analysis of decoupling factors, this study finds that the technology factor and the population scale factor can promote decoupling in the future. 4. The total recyclable scrap steel resources will rise from 11.05 Mt to 19.48 Mt from 2023 to 2060. Depreciation scrap has always been the main source of recyclable scrap steel resources and will reach 17.96 Mt in 2060, accounting for 88% of the total recyclable scrap steel, underscoring its importance in the circular steel economy. In summary, the findings of this research offer relevant information necessary for drafting scrap metal recycling and steel production policies. This information can help stakeholders make more informed decisions regarding recycling and steel- crap management within a region. Future research can expand the framework to compare stainless steel with other alloys, so as to further enhance its relevance to the global sustainable development strategy of materials, and evaluate the energy-saving and emission-reduction potential of the steel industry according to the analysis results [59]. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15126506/s1](https://www.mdpi.com/article/10.3390/app15126506/s1)]([https://www.mdpi.com/article/10.3390/app15126506/s1](https://www.mdpi.com/article/10.3390/app15126506/s1)), Text SI: Accounting of the five downstream sectors' stocks; Text SI: Tapio-LMDI model; Text S3: Steel demand forecast; Table S1: Iron-containing products in Henan Province; Table S2: The steel contents of different products; Table S3: Criteria of the decoupling situation; Table S4: List of parameters; Figure S1: Amounts and composition of steel stocks in 18 prefecture-level cities in Henan; Figure S2: In-use stocks utilization intensity; Figure S3: Projections of steel demand. References [10; 12; 14; 15; 30; 39; 41; 43; 57; 60; 61] are cited in the supplementary materials. **Author Contributions:** Conceptualization, Y.L. ([PERSON]); methodology, Y.L. ([PERSON]); validation, Y.L. ([PERSON]) and S.W. ; formal analysis, Y.L. ([PERSON]) and S.W. ; investigation, Y.L. ([PERSON]), S.W., Y.L. ([PERSON]), H.S. and Y.Z. ; resources, R.Z. ; data curation, Y.L. ([PERSON]) and S.W. ; writing--original draft preparation, Y.L. ([PERSON]); writing--review and editing, Y.L. ([PERSON]), S.W., Y.L. ([PERSON]), H.S. and Y.Z. ; visualization, [PERSON] ([PERSON]); supervision, S.W. ; project administration, S.W.