Fuqiang Zheng

Gas-based reduction of vanadium titano-magnetite concentrate: behavior and mechanisms

AbstractThe reduction of vanadium titano-magnetite pellets by H2–CO at temperatures from 850 to 1050°C was investigated in this paper. The influences of pre-oxidation treatment, reduction temperature, and

Effects of high pressure roller grinding on size distribution of vanadium-titanium magnetite concentrate particles and improvement of green pellet strength

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Preparation of High-Quality Titanium-Rich Material from Titanium Slag with High Ca and Mg Content by Activation Roasting Process

VH2/(VH2+VCO) on the metallization degree were studied. The results showed that pre-oxidation played a substantial role in the reduction of vanadium titano-magnetite pellets. During the reduction process, the metallization degree increased with increasing temperature and increasing

Control of the Forming Behavior of Anosovite in the Reduction of Ilmenite by Hydrogen

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Effects of Basicity and MgO in Slag on the Behaviors of Smelting Vanadium Titanomagnetite in the Direct Reduction-Electric Furnace Process

VH2/(VH2+VCO). The phase transformation of pre-oxidized vanadium titano-magnetite pellets during the reduction process under an H2 atmosphere and a CO atmosphere was discussed, and the reduced samples were analyzed by scanning electron microscopy (SEM) in conjunction with back scatter electron (BSE) imaging. The results show that the difference in thermodynamic reducing ability between H2 and CO is not the only factor that leads to differences in the reduction results obtained using different atmospheres. Some of Fe3−xTixO4 cannot be reduced under a CO atmosphere because of the densification of particles’ structure and because of the enrichment of Mg in unreacted cores. By contrast, a loose structure of particles was obtained when the pellets were reduced under an H2 atmosphere and this structure decreased the resistance to gas diffusion. Moreover, the phenomenon of Mg enrichment in unreacted cores disappeared during H2 reduction. Both the lower resistance to gas diffusion and the lack of Mg enrichment facilitated the reduction of vanadium titano-magnetite.

Reduction Behaviors of Iron, Vanadium and Titanium Oxides in Smelting of Vanadium Titanomagnetite Metallized Pellets

A novel process to prepare titanium dioxide from Ti-bearing electric furnace slag by NH4HF2-HF leaching and hydrolyzing process has been developed. In this present study, the effects of [NH4+]/[F] mXolar ratio, leaching temperature, [F] concentration, liquid/solid mass ratio, leaching time on the Ti extraction, and the phase transformations have been investigated to reveal the leaching mechanism of Ti-bearing electric furnace slag in NH4HF2-HF solution. In the NH4HF2-HF leaching process, the MgTi2O5 and Al2TiO5 are converted to TiF62- and Mg-Al-bearing precipitate. Ti extraction rate reached 98.84% under the optimal conditions. In addition, 98.25% iron ions can be removed in the presence of NaCl prior to hydrolysis process. The effects of pH and temperature on the selective hydrolysis of TiF62- during hydrolysis process were also studied. In the hydrolysis process, the TiF62- is converted to (NH4)2TiOF4. By calcination, high grade TiO2 powder with its purity of 99.88% was obtained, using which the products, well crystallized anatase and rutile, were obtained through roasting at 800°C and 1000°C, respectively.