Fe 2 MoO 4 as a Precursor Material for Mo Alloying in Steel (Part II): Up‐Scaling Test

• Published in: Steel research international Vol. 82; no. 8; pp. 886 - 897
• Main Authors: Chychko, A., Teng, L., Nzotta, M., Seetharaman, S.
• Format: Journal Article
• Language: English
• Published: 01.08.2011
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.201100026

Abstract The Mo yield when using three different alloying mixtures (MoO 3 +C; MoO 3 +C + FeO x ; and MoO 3 + C + CaO) was tested both in laboratory experiments (16 g and 0.5 kg scale) and industrial trials (3 ton scale). The alloying is based on in‐situ formation of compounds of Mo in the mixtures from molybdenite concentrate with industrial grade Fe 2 O 3 . Thermogravimetry (TGA) and X‐ray diffraction (XRD) analyses were performed to identify the reduction steps and final products of the alloying mixtures. At least two steps of mass change were discovered during the reduction of all tested mixtures by carbon. The Mo yield for MoO 3  + C mixture is 93% which was confirmed by both laboratory and industrial experiments. The Mo yield for MoO 3  + C + CaO mixture is around 92% during 16 g scale laboratory and 3 ton scale industrial tests. The best results were obtained in the case of the mixture which contained FeO x , MoO 3 and C, resulting in the Mo yield up to 98% at all the experiment scale levels. It was found that the combination of both lower evaporation and fast reduction by carbon of the mixture along with further dissolution in steel are necessary to provide high Mo yield during steel alloying. The calculated mass balance of 3 ton trial heats showed that only a small part of initial Mo amount (8–13 ppm) has gone into slag.