"A common feature of all red muds is the presence of substantial levels of iron oxide, present either as hematite or a hydrated ferric oxide. The iron oxide is the source of much of the cost of red mud treatment and disposal, and hinders the use of chemical processes for recovering the titania and other constituents. As a result, many proposed red mud treatment schemes feature a preliminary iron-removal step. An approach proposed in this research program is to reduce the ferric iron contents in red mud to magnetite, which is ferromagnetic and can be recovered by low-gradient magnetic separation. Magnetic separation of the magnetite will generate an iron-oxide concentrate which could be used by an iron-ore processor, leaving behind a residue smaller in volume and more easily processed for the recovery of more valuable constituents. This new process uses a "direct reduction" approach, mixing dried mud with several potential reductants, including coal, charcoal, sawdust and bagasse. Several variables which may have a potential impact on this new process such as the type of mud, the temperature, reduction time, and the mud/reducing agent ratio were investigated.
The results indicate that the ferric iron in all three red muds is readily converted to magnetite, even at low temperatures. Sawdust and bagasse are more effective reducing agents than coal or charcoal, especially at lower temperatures. The conversion of ferric iron in red muds to magnetite is highly dependent on the temperature and mud/reducing agents ratio. However, the conversion quickly becomes invariant with time, suggesting that the reduction process might be controlled by the surface reaction"--Abstract, page iii.
Schlesinger, Mark E.
Watson, John L.
Materials Science and Engineering
M.S. in Metallurgical Engineering
University of Missouri--Rolla
x, 54 pages
© 2001 Qinfang Xiang, All rights reserved.
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Xiang, Qinfang, "Red mud minimization by iron removal-iron reduction" (2001). Masters Theses. 2025.
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