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在铝土矿拜耳法溶出的同时使赤铁矿转化为磁铁矿对高铁铝土矿的经济高效利用至关重要。在热力学计算的基础上,实验研究氧化铁在碱溶液中的水热还原行为。热力学计算结果表明:在适当的氧化还原电位条件下,氧化铁在碱性溶液体系中可转化为磁铁矿。实验结果表明:铁粉与氧化铁粉或者铁粉与水在碱性水溶液中反应形成四氧化三铁,反应转化率均随温度和碱浓度的升高而显著升高,这说明四氧化三铁的形成过程可能经历铁粉和氧化铁粉溶解分别形成含铁离子Fe(OH)3-和Fe(OH)4-,Fe(OH)3-和Fe(OH)4-进一步反应生成四氧化三铁两个过程。同时,铝酸根对氧化铁在碱溶液中的水热还原没有显著影响,在其拜耳法溶出过程中一水硬铝石中的铁矿物可以转化为磁铁矿。
The conversion of hematite to magnetite at the same time as the dissolution of bauxite by Bayer process is crucial for the economical and efficient utilization of high-iron bauxite. On the basis of thermodynamic calculation, the hydrothermal reduction behavior of iron oxide in alkaline solution was experimentally studied. Thermodynamic calculations show that iron oxide can be converted to magnetite in an alkaline solution under the proper redox potential. The experimental results show that iron and iron oxide powder or iron powder and water react in alkaline aqueous solution to form ferriferous oxide. The reaction conversion rate increases with the increase of temperature and alkali concentration, which indicates that ferroferric oxide The formation process may experience the dissolution of iron powder and iron oxide powder to form Fe (OH) 3- and Fe (OH) 4-, Fe (OH) 3- and Fe (OH) Iron two processes. At the same time, aluminate has no significant effect on the hydrothermal reduction of iron oxide in alkaline solution, and the iron minerals in diaspore can be converted to magnetite during Bayer process dissolution.