Metal Droplet Migration and Gathering in Semi-molten Sludge at Low Temperature Reduction

• Published in: Transactions of the Indian Institute of Metals 2024, Vol.77 (9), p.2335-2342
• Main Authors: Li, Qiuju, Han, Bowen, Liang, Cong, Tan, Junyi
• Format: Article
• Language: English
• Subjects: Carburizing; Chemistry and Materials Science; Clumps; Corrosion and Coatings; Droplets; Iron; Low temperature; Materials Science; Melting points; Metal particles; Metallic Materials; Microchannels; Nickel; Original Article; Packing density; Pickling; Sludge; Stainless steels; Tribology
• ISSN: 0972-2815; 0975-1645
• DOI: 10.1007/s12666-024-03313-z

The stainless-steel pickling sludge contained chromium, nickel, and other metal elements, which not only increased the disposal costs but also wasted useful metal resources. The aim of the project was to find the factors that affected the metal droplets gathering from sludge during the semi-molten low temperature reduction. The reduced metals formed low-melting-point metal droplets after carburization. The result showed that the content of Fe, Cr, Ni, and C in metal alloy was 80.89%, 10.02%, 2.68%, and 5.41, respectively, over 1250 °C. The average time for the metal liquid in each microchannel gathering to form metal particles was 1.3*10 −5  s based on the model of metal droplets gathering and growth. The compaction density of graphite–sludge mixture clumps and temperature had significant effect on metal droplets gathering and aggregation. The average size of metal particles was about 73 μm and the recovery degree of Fe, Cr, and Ni elements was 93.6%, 84.2%, and 91.8%, respectively, at 1300 °C as packing density of the sample was 0.53, respectively. The content of Cr in non-magnetic tailings was only 0.04%.