Mitigation of waste sulfur acid in lead smelting: Substance flow analysis of a case study in China

The migration and conversion of sulfur resources throughout the entire production process of lead smelting (LS), a key process in non-ferrous heavy metal production, underscores the significance of analyzing its flow characteristics. This study elucidates the sulfur flow dynamics during the lead smelting process based on production data from a representative group company in China in 2020. We found a predominantly singular structure of sulfur products, resulting in a low corresponding sulfur utilization index (∼89.23 %). Conversely, the sulfur waste index was notably high (∼9.68 %). Here we propose a three-phase optimization strategy: optimizing the structure of raw materials and products in the initial stage, augmenting the scale and structure of primary processes in the middle stage, and advancing industrial symbiosis technology, alongside adjusting industry scale, product structures, and promoting pollutant end-treatment technologies in the latter stages. Through the implementation of these measures, it is anticipated that approximately 180,000 tons of waste acid can be mitigated in the non-ferrous heavy metal industry while 257,600 tons of sulfur resources can be recycled in lead smelting annually in China.