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用拜耳法处理高硫铝土矿时,矿石中的硫化物会与含铁物质在铝酸钠溶液中反应,进而导致严重的设备腐蚀和氧化铝产品降级。本文作者研究含铁物质对含硫离子(S~(2-),S_2O_3~(2-),SO_3~(2-)和SO_4~(2-))在铝酸钠溶液中转化的影响。研究结果表明:铁粉、Fe_2O_3和Fe_3O_4均难以与SO_3~(2-)和SO_4~(2-)反应,而且所有含铁物质,特别是铁粉,均能促进S_2O_3~(2-)转化为SO_3~(2-)和S~(2-);在高温条件下铁粉与铝酸钠溶液反应生成Fe(OH)_3~-),进而可与S~(2-)反应生成FeS_2,但Fe_2O_3和Fe_3O_4对S~(2-)的反应影响很小;升高温度、延长反应时间、增加铁粉添加量、提高溶液中Na_2O_k与Al_2O_3的摩尔比和苛碱浓度均有利于S_2O_3~(2-)向SO_3~(2-)和S~(2-)转化。本研究结果有助于在拜耳法处理高硫铝土矿过程中开发减缓设备腐蚀和降低碱耗的技术。
When the high-sulfur bauxite is treated with the Bayer process, sulphides in the ore react with the iron-containing material in the sodium aluminate solution, leading to severe equipment corrosion and degradation of the alumina product. The authors investigated the effect of iron-containing materials on the conversion of S ~ (2 -), S_2O_3 ~ (2-), SO_3 ~ (2-) and SO_4 ~ (2-) in sodium aluminate solution. The results show that iron, Fe 2 O 3 and Fe 3 O 4 are hard to react with SO 3 2- and SO 4 2-, and all ferrous materials, especially iron, can promote the conversion of S 2 O 3 2- into SO_3 ~ (2-) and S ~ (2-). At high temperature, Fe (OH) 3 ~ + reacts with the sodium aluminate solution and then reacts with S ~ (2-) to form FeS_2. The effect of Fe 2 O 3 and Fe 3 O 4 on the reaction of S 2 - is very small. The effects of increasing the temperature, extending the reaction time, increasing the amount of iron powder, increasing the molar ratio of Na 2 O 2 to Al 2 O 3 and the concentration of caustic soda are favorable for the reaction of S 2 O 3 ~ -) to SO_3 ~ (2-) and S ~ (2-) conversion. The results of this study contribute to the development of techniques for slowing equipment corrosion and reducing alkali consumption during Bayer process treatment of high-sulfur bauxite.