Environmental and economic impacts assessment of prebaked anode production process: a case study in Shandong Province, China

Abstract

With the development of China's electrolytic aluminum industry, the consumption of prebaked anode has increased rapidly. However, the prebaked anode production process shares common characteristics such as excessive energy consumption and air pollutants emission. Therefore, it is imperative to evaluate the environmental and economic impacts of prebaked anode production process comprehensively. Following the life cycle assessment approach, this study provides life cycle inventory for the production process of the localized prebaked anode in China. Similarly, the “cradle-to-gate” environmental impact and economic cost of prebaked anode were analyzed. From the perspective of source tracking, the key processes and materials are identified according to environmental impacts. The results show that top five environmental impact categories are: freshwater eutrophication, human toxicity, freshwater ecotoxicity, marine ecotoxicity and fossil depletion. The key processes with significant environmental impact are mixing molding process and coarse crushing process which accounted for 45.87% and 45.43% of the overall environmental impact load, respectively. The key materials with significant environmental impact are petroleum coke and coal pitch which accounted for 45.40% and 45.04% of the overall environmental impact load, respectively. The sensitivity of various allocation methods is analyzed. The allocation factor of market value allocation and mass allocation is 99.79% and 97.31%, respectively. According to the sensitivity analysis results, the top priority should be assigned to the optimization of the key process such as mixing molding process, followed by the coarse crushing process.