Feasible low-cost conversion of red mud into magnetically separated and recycled hybrid SrFe12O19@NaP1 zeolite as a novel wastewater adsorbent

Cheng, Yong; Xu, Longjun; Jiang, Zao; Liu, Chenglun; Zhang, Qiyuan; Zou, Yi; Chen, Yan; Li, Jingya; Liu, Xiuzhu

doi:10.1016/j.cej.2020.128090

Cited by 36 publications

(5 citation statements)

References 53 publications

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“…A-, X-, Y-, P-type zeolite and sodalite formation was documented after the alkaline hydrothermal process of fly ash in the temperature range between 45 • C and 90 • C [26][27][28], whereas in our previous papers, the synthesis of a GIS zeolite with a cactus-like and wool ball-like shape was performed at 40 and 90 • C using red mud [29]. According to Xie and co-workers [30], conventional hydrothermal treatment of red mud determined the formation of 4A-zeolite, whereas Cheng et al [31] formed a NaP1 zeolite at different temperatures (90-130 • C). The use of RM in combination with FA was carried out to form A-, X-, and ZK-5-type zeolites with magnetic properties at low temperatures (25-40 • C) [32].…”

Section: Introductionmentioning

confidence: 94%

Determining the Role of Water Molecules in Sodalite Formation Using the Vapor Phase Crystallization Method

Belviso

2024

Processes

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The efficiency of the vapor phase crystallization (VPC) process in zeolite formation using mixtures of a natural source (obsidian) and common waste materials (red mud and fly ash) was analyzed. The aim was to demonstrate that water molecules available during this treatment control mainly the synthesis of sodalite, regardless of the raw material used, as long as it is rich in amorphous silica and alumina pre-fused with NaOH. The data indicate that increasing the temperature to generate steam from distilled water during the VPC process results in the continuous transformation of amorphous material into sodalite and, subordinately, cancrinite. The formation of the newly formed phases was monitored by powder XRD and SEM.

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Section: Introductionmentioning

confidence: 94%

Determining the Role of Water Molecules in Sodalite Formation Using the Vapor Phase Crystallization Method

Belviso

2024

Processes

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“…The authors reported the synthesis of zeolite X adding bauxite to laterite during the hydrothermal process, thus determining the appropriate Si/Al ratio for this type of zeolite formation. Finally, many more papers have documented zeolite synthesis from waste bauxite products (red mud or bauxite tailings) [12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

A green process for zeolite synthesis: low-temperature vapor phase treatment of natural bauxites

2022

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In this work, three samples of bauxite were used as inexpensive sources for the zeolite formation by a green process based on vapor-phase crystallization (VPC) method. The synthesis was carried out using a water bath with deionized water heated at 35, 45, 60 or 90 °C. During the process, NaOH pre-fused bauxites were contacted only with vapor from the liquid. The results indicate that sodalite formed in all the samples after VPC at higher temperatures (60 °C and 90 °C). Large amount of zeolite A was instead synthesized in the sample characterized by SiO2/Al2O3 ratio next to 1 and after vapor treatment at 35 °C and 45 °C. These data highlight the determining role of both raw material chemical composition and amount of water molecules in type of zeolite formed by vapor crystallization method. Moreover, the results indicate that VPC process made it possible to synthesize zeolite generating no water waste.

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“…Thus, the contradiction between technology and economy, as well as safety and environmental protection issues, means the comprehensive utilization of BRM is still at the experiment and research stage, limiting its industrial application and large-scale popularity [21]. Currently, the emissions of BRM in China are as high as 600 million tons, while the comprehensive utilization rate is only 4% [22]. Therefore, it is exceptionally urgent to minimize the hazards of BRM and achieve its multichannel and large-scale utilization.…”

Section: Introductionmentioning

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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Feasible low-cost conversion of red mud into magnetically separated and recycled hybrid SrFe12O19@NaP1 zeolite as a novel wastewater adsorbent

Cited by 36 publications

References 53 publications

Determining the Role of Water Molecules in Sodalite Formation Using the Vapor Phase Crystallization Method

Determining the Role of Water Molecules in Sodalite Formation Using the Vapor Phase Crystallization Method

A green process for zeolite synthesis: low-temperature vapor phase treatment of natural bauxites

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

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