Application of Red Mud in Wastewater Treatment

Wang, Li; Hu, Guangyan; Lyu, Fei; Yue, Tong; Tang, Honghu; Han, Haisheng; Yang, Yue; Sun, Wei

doi:10.3390/min9050281

Cited by 79 publications

(24 citation statements)

References 103 publications

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“…China's alumina output has been growing rapidly in the past two decades, and the output of alumina in 2019 has reached about The rapid increase in alumina production followed with the fast-growing production of its byproduct, red mud (RM). RM, also named bauxite residue, is the major waste produced during the alumina production process [4]. Depending on the quality of the bauxite and its processing [5], about 15-40% of processed bauxite ore enters the waste in the form of alkaline slurry [6].…”

Section: Introductionmentioning

confidence: 99%

Progress on the Industrial Applications of Red Mud with a Focus on China

et al. 2020

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Red mud (RM), also called bauxite residue, is a strong alkaline industrial waste generated during the alumina production process. The annual production of RM in China is large, but its average utilization rate is low (only 4%). High generation and low consumption make the disposal of RM mainly by stockpiling, which has caused serious heavy metal pollution and radioactive contamination. In this paper, the various industrial utilization methods of RM in China during the past 60 years have been introduced. Moreover, some recent industrial progresses were referred. The results show that RM can be widely used in building materials, valuable metals extraction, and some novel utilization methods, such as silica-calcium fertilizer, inorganic polymer material and desulfurizer. Most of the industrial utilization methods of RM have been used until now and some successfully applied to other aluminum plants, providing some feasible routes for a large amount utilization of RM. Some industrial utilization methods (such as oil well cement and calcium silicon fertilizer) have not been used due to some problems that cannot be ignored, but it provided a lot of valuable experience and was helpful for the subsequent RM utilization. Moreover, some novel and feasible RM utilization methods were proposed and successfully industrialized, which showed that RM has a broader application prospect. Many actual practices showed that the best way to safely dispose of RM was to develop technology that could consume large amounts of RM or transform it into secondary resources, which may need more time and effort.

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Section: Introductionmentioning

confidence: 99%

Progress on the Industrial Applications of Red Mud with a Focus on China

et al. 2020

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“…After mixing with cementitious materials and water at a certain ratio and at a high speed, RMCB is produced and transported via piping through a drill boring and an underground laneway into a mining goaf [52]. As a strongly alkaline solid waste, in BRM, there are large amounts of free alkalis, chemical binding alkali, fluoride, and heavy metal ions, which are difficult to remove and easily pollute the surface environment as a result of open storage [53]. However, with RMCB, the surface pollution caused by BRM will not be transferred underground; the main reasons follow:…”

Section: Discussionmentioning

confidence: 99%

Environmental Safety Analysis of Red Mud-Based Cemented Backfill on Groundwater

Zhang

Feng

et al. 2021

IJERPH

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As one of the main industrial solid wastes, there are a large number of free alkaloids, chemically bound alkaloids, fluoride, and heavy metal ions in Bayer process red mud (BRM), which are difficult to remove and easily pollute groundwater as a result of open storage. In order to realize the large-scale industrial application of BRM as a backfilling aggregate for underground mining and simultaneously avoid polluting groundwater, the material characteristics of BRM were analyzed through physical, mechanical, and chemical composition tests. The optimum cement–sand ratio and solid mass concentration of the backfilling were obtained based on several mixture proportion tests. According to the results of bleeding, soaking, and toxic leaching experiments, the fuzzy comprehensive evaluation method was used to evaluate the environmental impact of BRM on groundwater. The results show that chemically bound alkaloids that remained in BRM reacted with Ca2+ in PO 42.5 cement, slowed down the solidification speed, and reduced the early strength of red mud-based cemented backfill (RMCB). The hydration products in RMCB, such as AFT and C-S-H gel, had significant encapsulation, solidification, and precipitation inhibition effects on contaminants, which could reduce the contents of inorganic contaminants in soaking water by 26.8% to 93.8% and the leaching of toxic heavy metal ions by 57.1% to 73.3%. As shown by the results of the fuzzy comprehensive evaluation, the degree of pollution of the RMCB in bleeding water belonged to a medium grade Ⅲ, while that in the soaking water belonged to a low grade II. The bleeding water was diluted by 50–100 times to reach grade I after flowing into the water sump and could be totally recycled for drilling and backfilling, thus causing negligible effects on the groundwater environment.

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“…Over the past few years, red mud (RM), a solid waste generated during the production of the alumina industry, has received several attentions due to its huge pile and resource utilization difficulties 8 – 11 . Red mud is strongly alkaline, has large porosity and high dispersibility, which make it have a good adsorption effect on metal cations 12 .…”

Section: Introductionmentioning

confidence: 99%

Cadmium adsorption performance and mechanism from aqueous solution using red mud modified with amorphous MnO2

Pang

Zhao

et al. 2022

Sci Rep

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In this study, red mud modified by manganese dioxide(MRM) was utilized as an adsorbent to effectively remove Cd2+ from aqueous solution. The characteristics were analysed by SEM–EDS, XRD, BET, FTIR and XPS. Different factors that affected the Cd2+ removal on MRM, such as dosage, initial pH, initial Cd2+ concentration, were investigated using batch adsorption experiments. Simultaneously, the adsorption kinetics, adsorption isotherms and adsorption thermodynamics of Cd2+ were also investigated using adsorption experiments data. The characterization results showed that MRM had a rougher, larger specific surface area and pore volume (38.91 m2 g−1, 0.02 cm3 g−1) than RM (10.22 m2 g−1, 0.73 cm3 g−1). The adsorption experiments found that the equilibrium adsorption capacity of MRM for Cd2+ was significantly increased to 46.36 mg g−1, which was almost three times that of RM. According to the fitting results, the pseudo-second-order kinetic model described the adsorption process better than the pseudo-first-order kinetic model. The Langmuir model fitted the adsorption isotherms well, indicating that the adsorption process was unimolecular layer adsorption and the maximum capacity was 103.59 mg g−1. The thermodynamic parameters indicated that the adsorption process was heat-trapping and spontaneous. Finally, combined XPS and FTIR studies, it was speculated that the adsorption mechanisms should be electrostatic attachment, specific adsorption (i.e., Cd–O or hydroxyl binding) and ion exchange. Therefore, manganese dioxide modified red mud can be an effective and economical alternative to the removal of Cd2+ in the wastewater treatment process.

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Application of Red Mud in Wastewater Treatment

Cited by 79 publications

References 103 publications

Progress on the Industrial Applications of Red Mud with a Focus on China

Progress on the Industrial Applications of Red Mud with a Focus on China

Environmental Safety Analysis of Red Mud-Based Cemented Backfill on Groundwater

Cadmium adsorption performance and mechanism from aqueous solution using red mud modified with amorphous MnO2

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