The Optimal Physical Treatment Process for Production of High-grade Iron Concentrate from Waelz Kiln Slag

Abstract

The aim of this study was to develop a physical treatment method for obtaining iron concentrate with a grade higher than 60% from slag generated in the Waelz Kiln (WK) process. The size of the WK slag used in this work was several millimeters, with T-Fe and ZnO contents of 40.24% and 1.03%, respectively. The slag samples were pulverized in a laboratory rod mill for various grinding times, followed by a magnetic separation test under a low magnetic intensity of 0.05 T initially. The results showed that the highest iron grade was obtained from samples with a grinding time of 10 min. Additionally, for a grinding time of 20 min, the highest grade and recovery ratios were achieved at a magnetic intensity of 0.8 T. Based on these findings, the optimal physical treatment process proposed in this study resulted in iron concentrates with a grade of 61.34% and an enrichment ratio of 1.52.

The Waelz Slag from Electric Arc Furnace Dust Processing: Characterization and Magnetic Separation Studies

“…The association of iron and copper agrees well with our experimental data, especially for the WS2 sample (Figures 14 and 15), where curves of Cu recovery resemble curves of Fe recovery. Regarding zinc, its residual contents in the concentrate are quite high, as in the study [23], which is likely due to a substantial part of zinc ferrite being associated with magnetite [78]. Thus, the selective segregation of copper and zinc in the magnetic or non-magnetic fraction, respectively, was not achieved using magnetic separation.…”

“…Few studies on pyrometallurgical methods for the Waelz slag treatment to remove zinc and lead have been carried out [21,22], but even after the treatment, the residue obtained was unsuitable for the application in iron and steel industry due to the high contents of the impurities. A recent study was conducted [23] on the magnetic separation of Waelz slag for iron recovery. This approach deserves attention because it may provide the segregation of valuable elements without the use of costly and environmentally hazardous pyrometallurgical or hydrometallurgical methods.…”