Reduction of Magnetite from Copper Smelting Slag in the Presence of a Graphite Rod

Through the reduction reaction of Fe 3 O 4 and graphite rod, the viscosity of slag was reduced and the settlement of matte in slag was promoted. The reduction of Fe 3 O 4 in copper slag by a graphite rod was studied and the kinetics of the reduction process analyzed. The results show that the content of Fe 3 O 4 decreased with increase in reduction temperature and reduction time. The slag samples after reduction were examined and found to consist of three layers: a slag foam layer, a fayalite layer, and a matte layer. A substantial number of large-sized matte particles were found in the slag foam layer. Also, a layer of Fe 3 O 4 was attached to the upper surface of the matte layer. The reduction of Fe 3 O 4 was concluded to be a second-order reaction, the apparent activation energy was 610 kJ/mol, and the limiting step was the Boudouard reaction. Graphical Abstract