Analysis of carbon footprint of iron concentrate products based on different allocation methods

As the front end of the steel industry supply chain, mining enterprises' implementation of life cycle environmental performance assessment for iron concentrate products will facilitate downstream steel manufacturers in obtaining accurate carbon emission information. This paper systematically reviews the co-product allocation rules in existing LCA and carbon footprint standards, conducting a comparative study on three allocation methods(system expansion, mass allocation, and economic allocation) for iron concentrate carbon footprint under different data acquisition approaches at two domestic mining enterprises. Results indicate that when applying Approach II(using product-specific verified data as the baseline), the calculated carbon footprint aligns better with international standards, yielding more accurate and reasonable values. The selection of allocation methods significantly impacts carbon footprint outcomes: compared with mass allocation, system expansion reduces carbon footprint by 2.94% for Mine A and 0.12% for Mine B, while economic allocation achieves greater reductions of 10.64% and 6.69% respectively. These findings demonstrate the critical importance of data selection methodology and allocation principle optimization in carbon footprint accounting.