Greek “red mud” residue: A study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process

2013 ◽  
Vol 254-255 ◽  
pp. 193-205 ◽  
Author(s):  
Michail Samouhos ◽  
Maria Taxiarchou ◽  
Petros E. Tsakiridis ◽  
Konstantinos Potiriadis
2013 ◽  
pp. 125-130 ◽  
Author(s):  
Mingjun Rao ◽  
Jinqiang Zhuang ◽  
Guanghui Li ◽  
Jinghua Zeng ◽  
Tao Jiang

2014 ◽  
Vol 878 ◽  
pp. 254-263 ◽  
Author(s):  
Chuan Long Wang ◽  
Hui Fen Yang ◽  
Bei Ping Jiang ◽  
Jin Long Zhang ◽  
Lin Fei Lu ◽  
...  

Iron recovery from a lead slag in Henan province was carried out with the technique of coal-based direct reduction followed by magnetic separation. Scanning electron microscopy (SEM) was used to investigate the transformation of iron-containing minerals and the particle size of metallic iron generated by coal reduction. The results showed that technique is feasible for iron recovery from the lead slag. Under the conditions of weight ratio of slag: coal: CaO as 50:15:5, the roasted temperature of 1250 °C for 45 min, and then two stage of grinding and twice magnetic separation, the metallic iron powder was obtained with the iron grade of 92.85% and iron recovery of 92.85%. The iron-containing minerals in the forms of hercynite, fayalite and maghemite were mianly transformed into metallic iron and the particle size of metallic iron was more than 50μm. Therefore, the metallic iron in roasted product can be dissociated by coarse grinding and further was separated by magnetic separation to recover the metallic iron.


Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 222
Author(s):  
Chiara Cardenia ◽  
Efthymios Balomenos ◽  
Pritii Wai Yin Tam ◽  
Dimitrios Panias

In this study an integrated process is presented as a suitable method to transform Fe3+ oxides present in bauxite residue into magnetic oxides and metallic iron through a microwave roasting reduction, avoiding the formation of hercynite (FeAl2O4). In the first step, all the alumina phases were transformed into sodium aluminates by adding sodium carbonate as a flux to BR and then leached out through alkali-leaching to recover alumina. Subsequently, the leaching residue was mixed with carbon and roasted by using a microwave furnace at the optimum conditions. The iron oxide present in the sinter was converted into metallic iron (98%). In addition, hercynite was not detected. The produced cinder was subjected to a wet high intensity magnetic separation process to separate iron from the other elements.


Author(s):  
Mingjun Rao ◽  
Jinqiang Zhuang ◽  
Guanghui Li ◽  
Jinghua Zeng ◽  
Tao Jiang

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1571
Author(s):  
Pavel Grudinsky ◽  
Dmitry Zinoveev ◽  
Denis Pankratov ◽  
Artem Semenov ◽  
Maria Panova ◽  
...  

Red mud is an iron-containing waste of alumina production with high alkalinity. A promising approach for its recycling is solid-phase carbothermic roasting in the presence of special additives followed by magnetic separation. The crucial factor of the separation of the obtained iron metallic particles from gangue is sufficiently large iron grains. This study focuses on the influence of Na2SO4 addition on iron grain growth during carbothermic roasting of two red mud samples with different (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21, respectively. Iron phase distribution in the red mud and roasted samples were investigated in detail by Mössbauer spectroscopy method. Based on thermodynamic calculations and results of multifactorial experiments, the optimal conditions for the roasting of the red mud samples with (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21 were duration of 180 min with the addition of 13.65% Na2SO4 at 1150 °C and 1350 °C followed by magnetic separation that led to 97% and 83.91% of iron recovery, as well as 51.6% and 83.7% of iron grade, respectively. The mechanism of sodium sulfate effect on iron grain growth was proposed. The results pointed out that Na2SO4 addition is unfavorable for the red mud carbothermic roasting compared with other alkaline sulfur-free additives.


JOM ◽  
1996 ◽  
Vol 48 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Paolo Plescia ◽  
Dante Maccari

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