Phase Transformation and Iron Separation Characteristics of High Iron and Low Silicon Red Mud Using Sodium Reduction

Abstract

Abstract: The high-temperature roasting of red mud can realize the form transformation of iron, aluminum and silicon, making it easy to separate and recover. However, there are few reports about the difference and mechanism of sodium reduction roasting reaction of high iron and low silicon red mud. The effects of reduction temperature, Na₂CO₃ addition and reduction time on the phase transformation and microstructure of high iron and low silicon red mud were investigated by X-ray diffraction analysis, and the difference of iron magnetic separation after reduction reaction was also analyzed. The results show that sodium combines with aluminum and silicon elements to form sodium aluminosilicate during reduction roasting, which effectively destroys the compact structure of Fe and Al elements. Hematite and goethite are converted into magnetite and wustite mostly, which promotes the reduction of iron oxides. The low melting point sodium-containing solid solution reduces the migration resistance and accelerates the growth of metal iron grains. Based on the disintegration of the Fe-Al structure and the formation of coarse-grained metal iron, the roasted product is subjected to grinding-magnetic separation, and iron recovery indicator with the TFe content 90.41% and Fe recovery rate 93.08% is obtained.

Key words: high iron and low silicon red mud, reduction roasting, sodium carbonate, phase transformation, iron separation

CLC Number:

TF09

ZHENG Fuqiang, DAI Yanni, HU Bing, LIU Chen, OUYANG Siwen, HU Peiwei. Phase Transformation and Iron Separation Characteristics of High Iron and Low Silicon Red Mud Using Sodium Reduction[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(1): 209-218.

References

[1] 邢磊, 杜培培, 龙跃. 熔分赤泥熔渣纤维化过程中熔体性能研究[J]. 硅酸盐通报, 2022, 41(9): 3162-3169.
XING L, DU P P, LONG Y. Study on melt properties of molten red mud slag during fiberization[J]. Bulletin of the Chinese Ceramic Society, 2022, 41(9): 3162-3169 (in Chinese).
[2] SAMOUHOS M, TAXIARCHOU M, TSAKIRIDIS P E, et al. Greek “red mud” residue: a study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process[J]. Journal of Hazardous Materials, 2013, 254/255: 193-205.
[3] GENG C, CHEN C, SHI X F, et al. Recovery of metals from municipal solid waste incineration fly ash and red mud via a co-reduction process[J]. Resources, Conservation and Recycling, 2020, 154: 104600.
[4] GRÄFE M, KLAUBER C. Bauxite residue issues: iv. Old obstacles and new pathways for in situ residue bioremediation[J]. Hydrometallurgy, 2011, 108(1/2): 46-59.
[5] LIU Z B, LI H X. Metallurgical process for valuable elements recovery from red mud: a review[J]. Hydrometallurgy, 2015, 155: 29-43.
[6] AGRAWAL S, DHAWAN N. Evaluation of red mud as a polymetallic source: a review[J]. Minerals Engineering, 2021, 171: 107084.
[7] 柳佳建, 陈伟, 周康根, 等. 赤泥中铁的回收利用研究进展[J]. 矿产保护与利用, 2021, 41(3): 70-75.
LIU J J, CHEN W, ZHOU K G, et al. Research progress on recovery and utilization of iron in red mud[J]. Conservation and Utilization of Mineral Resources, 2021, 41(3): 70-75 (in Chinese).
[8] 徐淑安, 邵延海, 熊述清, 等. 疏水团聚-磁种法回收赤泥中微细粒铁矿试验[J]. 矿产综合利用, 2015(6): 62-66.
XU S A, SHAO Y H, XIONG S Q, et al. Experimental study on magnetic separation of hematite and limonite fines using magnetic seeding with selective hydrophobic flocculation from red mud[J]. Multipurpose Utilization of Mineral Resources, 2015(6): 62-66 (in Chinese).
[9] LIU X, GAO P, YUAN S, et al. Clean utilization of high-iron red mud by suspension magnetization roasting[J]. Minerals Engineering, 2020, 157: 106553.
[10] 高建军, 齐渊洪, 居殿春, 等. 从赤泥中联合提取铁和氧化铝试验[J]. 钢铁, 2015, 50(9): 11-16.
GAO J J, QI Y H, JU D C, et al. Experiment on the combined extraction of iron and alumina from red mud[J]. Iron & Steel, 2015, 50(9): 11-16 (in Chinese).
[11] 李恒, 刘晓明, 赵喜彬, 等. 生物质松木锯末中低温还原高铁拜耳法赤泥[J]. 工程科学学报, 2017, 39(9): 1331-1338.
LI H, LIU X M, ZHAO X B, et al. Medium-low temperature reduction of high-iron Bayer process red mud using biomass pine sawdust[J]. Chinese Journal of Engineering, 2017, 39(9): 1331-1338 (in Chinese).
[12] YU J W, LI Y F, LV Y, et al. Recovery of iron from high-iron red mud using suspension magnetization roasting and magnetic separation[J]. Minerals Engineering, 2022, 178: 107394.
[13] YUAN S, LIU X, GAO P, et al. A semi-industrial experiment of suspension magnetization roasting technology for separation of iron minerals from red mud[J]. Journal of Hazardous Materials, 2020, 394: 122579.
[14] 王尚杰夫, 金会心, 雷二帅, 等. 赤泥、粉煤灰和磷石膏配碳碱性调控共烧结回收铁铝[J]. 中国冶金, 2023, 33(4): 119-126.
WANG S J F, JIN H X, LEI E S, et al. Recovery of iron and aluminum from red mud, fly ash and phosphogypsum by co-sintering under alkaline control of carbon addition[J]. China Metallurgy, 2023, 33(4): 119-126 (in Chinese).
[15] ZINOVEEV D, GRUDINSKY P, ZAKUNOV A, et al. Influence of Na₂CO₃ and K₂CO₃ addition on iron grain growth during carbothermic reduction of red mud[J]. Metals, 2019, 9(12): 1313.
[16] 郭志强, 燕可洲, 张吉元, 等. 煤矸石/粉煤灰对赤泥钠化还原焙烧反应的影响机制[J]. 化工学报, 2022, 73(5): 2194-2205.
GUO Z Q, YAN K Z, ZHANG J Y, et al. Influence mechanism of coal gangue/coal fly ash on the sodium reduction roasting reaction of red mud[J]. CIESC Journal, 2022, 73(5): 2194-2205 (in Chinese).
[17] 王玲, 周晨晨, 范燕青, 等. 赤泥转型-碱溶提铝过程钛的矿相转化[J]. 中国有色金属学报, 2022, 32(9): 2714-2725.
WANG L, ZHOU C C, FAN Y Q, et al. Mineral phase transformation of titanium in red mud transformation-alkali leaching aluminum process[J]. The Chinese Journal of Nonferrous Metals, 2022, 32(9): 2714-2725 (in Chinese).
[18] GUO Y X, ZHAO Q A, YAN K Z, et al. Novel process for alumina extraction via the coupling treatment of coal gangue and bauxite red mud[J]. Industrial & Engineering Chemistry Research, 2014, 53(11): 4518-4521.
[19] GRUDINSKY P, ZINOVEEV D, PANKRATOV D, et al. Influence of sodium sulfate addition on iron grain growth during carbothermic roasting of red mud samples with different basicity[J]. Metals, 2020, 10(12): 1571.
[20] SUI Y L, GUO Y F, TRAVYANOV A Y, et al. Reduction roasting-magnetic separation of vanadium tailings in presence of sodium sulfate and its mechanisms[J]. Rare Metals, 2016, 35(12): 954-960.
[21] GRUDINSKY P, ZINOVEEV D, YURTAEVA A, et al. Iron recovery from red mud using carbothermic roasting with addition of alkaline salts[J]. Journal of Sustainable Metallurgy, 2021, 7(3): 858-873.