The vanadium titano-magnetite (VTM) iron ore fines of 110-150 μm in diameter were reduced in a transparent quartz fluidized bed by 70%CO-30%H2 (volume fraction) mixtures. MgO powders served as coating agent to solve sticking problem. Two coating methods were introduced in this experiment: high temperature injection method and briquetting→oxidizing roast→crushing method. According to the experimental results, the minimum effective coating amount of MgO was 0. 1 mass%. The metallization ratio (MR) of the product rose from around 58% to above 90% with the above treatments. To investigate the sticking mechanism of fine ore, the morphology evolution was investigated. Instead of iron whiskers, an interlaced fibrous porous surface formed. The ulvospinel (2FeO·TiO2) in VTM is more difficult to be reduced than FeO according to thermodynamic calculation. XRD results showed that MgO diffused into Fe2O3 lattice before forming pleonaste (MgO·Fe2O3) during oxidizing roast at 1273 K. The melting point of the pleonaste is 1986 K and that made contribution to prevent the sticking problem.
Abstract
The vanadium titano-magnetite (VTM) iron ore fines of 110-150 μm in diameter were reduced in a transparent quartz fluidized bed by 70%CO-30%H2 (volume fraction) mixtures. MgO powders served as coating agent to solve sticking problem. Two coating methods were introduced in this experiment: high temperature injection method and briquetting→oxidizing roast→crushing method. According to the experimental results, the minimum effective coating amount of MgO was 0. 1 mass%. The metallization ratio (MR) of the product rose from around 58% to above 90% with the above treatments. To investigate the sticking mechanism of fine ore, the morphology evolution was investigated. Instead of iron whiskers, an interlaced fibrous porous surface formed. The ulvospinel (2FeO·TiO2) in VTM is more difficult to be reduced than FeO according to thermodynamic calculation. XRD results showed that MgO diffused into Fe2O3 lattice before forming pleonaste (MgO·Fe2O3) during oxidizing roast at 1273 K. The melting point of the pleonaste is 1986 K and that made contribution to prevent the sticking problem.
关键词
Key words: fluidized bed /
sticking /
oxide coating /
iron ore fines /
vanadium titano-magnetite.
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Key words
Key words: fluidized bed /
sticking /
oxide coating /
iron ore fines /
vanadium titano-magnetite.
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脚注
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基金
National Natural Science Foundation of China;National Basic Research Program of China 973 Program
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