Kinetics Study on Solid-phase Catalytic Reduction of Highly Impure Ilmenite by Thermal Analysis
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摘要: 通过热重分析方法研究了固态条件下高杂质钛铁矿的催化碳热还原机理。结果表明:杂质会阻碍钛铁矿还原,无催化剂时还原率较低,加入少量催化剂可以获得较高的还原率和较快的还原速度。催化剂不同的阴离子基团对反应有着不同的影响。在钠离子摩尔浓度相同的情况下,催化效果:四硼酸钠(Na2B4O7)>氟化钠(NaF)>氯化钠(NaCl)>硅酸钠(Na2SiO3)。在温度860~1 100℃范围内,钛铁矿碳热还原反应的主要控速环节是界面化学反应。无催化剂反应的表观活化能为260.976 kJ/mol;添加四硼酸钠的一组表观活化能降低最多,为226.182 kJ/mol。Abstract: In order to reduce the highly impure ilmenite by carbon at solid phase,the mechanism of the catalytic reduction of ilmenite by thermogravimetric analysis has been studied. The results show that impurities hinder the process of ilmenite reduction. Low reduction rate occurs during the catalyst-free reduction process while a higher reduction rate and a faster reduction velocity can be achieved by adding a small amount of catalyst. The different anionic groups of catalysts have different effects on the reaction. In the case of the same molar concentration of sodium ion,the catalyst having the best catalytic effect is Na2B4O7,successively followed by NaF,NaCl and Na2SiO3. In the temperature range of 860~1 100℃,the main rate-controlling step for ilmenite reduction is the interfacial chemical reaction. The apparent activation energy of the catalyst-free reaction is 260.976 kJ/mol; the reduction adding the catalyst of Na2B4O7 has the lowest apparent activation energy of 226.182 kJ/mol.
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Key words:
- ilmenite /
- kinetics /
- catalyzing /
- thermogravimetric analysis /
- reduction
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