Innovative B-PA binder for enhanced cold pelletization: a sustainable strategy for utilizing iron-containing dust and sludge

A large amount of iron dust and sludge is produced in the process of iron and steel metallurgy, and its efficient utilization has important economic value and environmental significance. In this study, a method of cold-bonded aggregate is used to co-process stainless steel pickling sludge (SSPS) and gravity dust (GD). The preparation process parameters of cold-bonded pellet are optimized. The role mechanism of the binder on cold-bonded aggregates is studied, and a new type of composite binder, bentonite-plant asphalt (B-PA), is invented. The optimal ratio of bentonite to plant asphalt is determined to be 3:1. The metallurgical performance of B-PA agglomerates is tested, with results showing an RDI +3.15 at 93.6%, a RI at 79.3%, an RSI at 14.2%, a DI at 4.01%, and a thermal cracking temperature reaching 721 °C. The microstructure of the agglomerates after performance testing is characterized using XRD and SEM. This cold-bonding pelletization technology is expected to be widely used in the efficient comprehensive utilization of metallurgical dust in the future, which is of great significance for reducing costs, increasing efficiency, and promoting green environmental protection in the steel industry.