Circular Economy

China Steel Corporation (CSC) is the only wholly integrated steel mill in Taiwan. The various oxide layers, rust, and other impurities on the surfaces of hot rolled steel coils need to be completely removed by an acid pickling process prior to the cold rolling process. However, the pickling liquid contains acidic rinse water, waste acid, dissolved metal salts of iron, iron chloride, and various alloy elements, which may potentially lead to environmental concerns due to improper handling. In order to adhere to the government's circular economy policy and to comply with national environmental regulations, CSC has established an acid regeneration plant (ARP) to purify and recycle the waste acid following the examples of advanced countries, such as Japan, European countries, and the United States. The products from the ARP are mainly regenerated hydrochloric acid (HCl) and iron oxide powder (Fe₂O₃). The regenerated hydrochloric acid is reintroduced into the pickling process, while iron oxide powder serves as an industrial raw material for soft and hard ferrite used in various electronic and electrical applications, including inductor components, transformers, motors, and so on. This successful example of resource reutilization can be considered as a good model of circular economy.

The process flow chart of the acid regeneration plant