Reduction of SO_2 to elemental sulfur over rare earth-iron catalysts
来源期刊：JOURNAL OF RARE EARTHS2009年第5期
论文作者：DENG Gengfeng LIAO Chunfa JIANG Kun CAO Xia
Key words：sulfur dioxide; catalytic reduction; sulfur; flue gas; rare earths;
Abstract: With coal gas as a reducing agent, the catalytic reduction of SO2 to sulfur in the flue gas produced in metallurgical processes was studied over catalysts of rare earth-Fe/Al_2O_3 (REFe/Al_2O_3). The catalytic activity of the REFe/Al_2O_3 catalyst on the reduction of SO_2 to sul-fur was investigated based on kinds and the contents of rare earths and different preparation method of the catalyst. Additionally, the mecha-nism of this catalytic reduction reaction was also explored. Results showed that different rare earth imposed different effect on the activity of the Fe/Al2O3 catalyst. Especially, the addition of Sm and Dy greatly improved the catalytic activity of Fe/Al_2O_3. The yield of sulfur over SmFe/Al_2O_3was increased to 86.62% at 360 ℃, which was 40.5% higher than that over Fe/Al_2O_3at the same temperature; and the sulfur yield over DyFe/Al_2O_3was increased to 91.62% at 400 ℃, 26.4% higher than that over Fe/Al_2O_3. The catalytic activity of REFe/Al_2O_3 was somehow dependent on the content of rare earth. For SmFe/Al_2O_3, the content of Sm was optimized to be about 1.0 wt.%. The rare earth catalyst prepared with different methods also showed varied activity. The sulfur yield over rare-earth transition metal catalysts follows the order: Sm and iron solution mixing impregnationSm first, then iron solution impregnationiron first, then Sm solution impregnation. The reaction mechanism of SO_2 reduction to sulfur with coal gas was proposed to be an intermediate mechanism.
DENG Gengfeng1，LIAO Chunfa1，JIANG Kun1，CAO Xia2
(1.School of Materials and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2.Nanchang Engineering and Research Institute of Nonferrous Metals, Nanchang 330000, China)
Abstract:With coal gas as a reducing agent, the catalytic reduction of SO2 to sulfur in the flue gas produced in metallurgical processes was studied over catalysts of rare earth-Fe/Al_2O_3 (REFe/Al_2O_3). The catalytic activity of the REFe/Al_2O_3 catalyst on the reduction of SO_2 to sul-fur was investigated based on kinds and the contents of rare earths and different preparation method of the catalyst. Additionally, the mecha-nism of this catalytic reduction reaction was also explored. Results showed that different rare earth imposed different effect on the activity of the Fe/Al2O3 catalyst. Especially, the addition of Sm and Dy greatly improved the catalytic activity of Fe/Al_2O_3. The yield of sulfur over SmFe/Al_2O_3was increased to 86.62% at 360 ℃, which was 40.5% higher than that over Fe/Al_2O_3at the same temperature; and the sulfur yield over DyFe/Al_2O_3was increased to 91.62% at 400 ℃, 26.4% higher than that over Fe/Al_2O_3. The catalytic activity of REFe/Al_2O_3 was somehow dependent on the content of rare earth. For SmFe/Al_2O_3, the content of Sm was optimized to be about 1.0 wt.%. The rare earth catalyst prepared with different methods also showed varied activity. The sulfur yield over rare-earth transition metal catalysts follows the order: Sm and iron solution mixing impregnationSm first, then iron solution impregnationiron first, then Sm solution impregnation. The reaction mechanism of SO_2 reduction to sulfur with coal gas was proposed to be an intermediate mechanism.
Key words:sulfur dioxide; catalytic reduction; sulfur; flue gas; rare earths;
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