 |
| Reduction of Siliceous Manganese Ore by Graphite |
Reduction of siliceous manganese ore containing 41.0 wt%Mn and 11.0 wt%SiO2 by graphite has been studied by the measurement of weight loss in argon atmosphere at 900, 1200 and 1400¡ãC and following by X-ray diffraction and Microprobe analyses. The ore was sized to ¨C150+53 ¦Ìm and preliminary calcined at 1000¡ãC in argon to ensure all weight loss in the experiments was due to reduction of the oxides present. The graphite was in the size fraction of ¨C300+100 ¦Ìm.
Reduction extent was calculated relative to 100% of iron and manganese reduction. About 6% of reduction was observed after 2 h at 900¡ãC and 35% after 2 h at 1200¡ãC; 132% of reduction was found after 6 h exposure at 1400¡ãC, this was due to silica reduction.
Reduction at 900¡ãC was limited to the reduction of iron oxides to FeO. Two reduction stages were distinguished at 1200 and 1400¡ãC. During the first stage which extended to about 25% at both 1200 and 1400¡ãC for 4-6 min iron oxides reduce to metallic iron and manganese oxides to MnO. It is suggested that at this stage oxides are reduced by CO gas. The second stage is the reduction of MnO to Mn and occurs via carbon in the metallic phase. This stage is suggested to be controlled by the diffusion of MnO in the solid ore at 1200¡ãC and in the liquid phase at 1400¡ãC. Slow rate of manganese ore reduction observed in the experiments may be attributed to the relatively high silica content in the ore.
|
|
|
Ningbo Wanxiang Imp.& Exp. Co., Ltd,
Add: Room 2607, Portman plaza,No.48,
North Caihong Road, Ningbo,china
P.C315040
TEL: 086-574-87737501 87737008
FAX: 086-574-87737502
Mail: info@cnnbwanxiang.com
Website: www.cnnbwanxiang.com |
|
