Geopolymerization mechanism of binder-free mine tailings by sodium silicate

Koohestani, Babak; Mokhtari, Pozhhan; Yilmaz, Erol; Mahdipour, Forough; Darban, Ahmad Khodadadi

doi:10.1016/j.conbuildmat.2020.121217

Cited by 82 publications

(27 citation statements)

References 54 publications

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“…The risk of AMD is related to the presence of sulfidic minerals such as pyrite (FeS 2 ) (Zhao, 2021). The presence of sulfides within cemented composites has a deleterious effect on paste backfill strength due to sulfate attack (Koohestani et al, 2021). Sulfate attack plays a main role in the mechanical strength and service life of concrete .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Strength and Quality of Cemented Mine Backfill Made up of Lead-Zinc Processing Tailings

2021

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Predicting the reactions of the backfill materials exposed to the effects of air and groundwater will eventually ensure an efficient and accurate mine fill system for sustainable mining operations. This paper reveals the effect of the mobility of sulfur ions within lead-zinc processing tailings on strength and quality of cemented mine backfills. Some laboratory tests such as X-ray diffraction, ion chromatography, scanning electron microscopy, combustion tests, chemical analysis, pH and zeta potential measurements were performed to better characterize the backfill’s mechanical and microstructural properties. Moreover, CEM II/A-P Portland pozzolan and CEM IV/A pozzolanic cements as ready-to-use cement products were used for cemented mine backfill preparation. To ensure the carrier of the lead-zinc tailings and to prevent the mobility of the sulfurous components, a binder content ranging from 3 to 7 wt% were employed in mine backfills. The experimental findings demonstrate that the used cement type and proportions were insufficient and some fractures are occurred in the samples due to the sulfur ion mobility. Accordingly, one can state clearly that the elemental analysis through the combustion test method can provide fast and reliable results in the determination of sulfur within lead-zinc processing tailings.

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Section: Introductionmentioning

confidence: 99%

Characterization of Strength and Quality of Cemented Mine Backfill Made up of Lead-Zinc Processing Tailings

2021

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“…The reason for the good performance was that the sodium silicate was not only adhered physically to the fibers, but the SiO 2 and Fe 2 O 3 were adsorbed onto the surface through chemical, electrostatic, and hydrogen bonding interactions. Therefore, the SiO 2 was strongly bound to the SSF [ 43 , 44 , 45 ].…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Si-Based High-Efficiency and High-Durability Superhydrophilic-Underwater Superoleophobic Membrane of Oil–Water Separation

Fang

Chen

et al. 2021

Materials

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Oil pollution is caused by the frequent discharge of contaminated industrial wastewater and accidental oil spills and is a severe environmental and health concern. Therefore, efficient materials and processes for effective oil–water separation are being developed. Herein, SiO2-Na2SiO3-coated stainless steel fibers (SSF) with underwater superoleophobic and low-adhesion properties were successfully prepared via a one-step hydrothermal process. The modified surfaces were characterized with scanning electron microscopy (SEM), and contact angle measurements to observe the surface morphology, confirm the successful incorporation of SiO2, and evaluate the wettability, as well as with X-ray diffraction (XRD). The results revealed that SiO2 nanoparticles were successfully grown on the stainless-steel fiber surface through the facile hydrothermal synthesis, and the formation of sodium silicate was detected with XRD. The SiO2-Na2SiO3-coated SSF surface exhibited superior underwater superoleophobic properties (153–162°), super-hydrophilicity and high separation efficiency for dichloromethane–water, n-hexane–water, tetrachloromethane–water, paroline–water, and hexadecane–water mixtures. In addition, the as-prepared SiO2-Na2SiO3-coated SSF demonstrated superior wear resistance, long-term stability, and re-usability. We suggest that the improved durability may be due to the presence of sodium silicate that enhanced the membrane strength. The SiO2-Na2SiO3-coated SSF also exhibited desirable corrosion resistance in salty and acidic environments; however, further optimization is needed for their use in basic media. The current study presents a novel approach to fabricate high-performance oil–water separation membranes.

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“…As shown in Figure 2 , when the BC particle size was 1700 μm (mark “1700 μm-BC”), the distribution of SS in the composite was uneven at the mass ratio of 10:3~5 (BC/SS). The reason for this is that large-size BC particles would form large gaps among each other, which would allow SS to easily deposit to the bottom of the composite during the hot-pressing, leading to the lack of adhesives at the top of the composite and failure of formation (as shown in the red dotted line of Figure 2 a) [ 32 ]. The composite with 270 μm-BC could be successfully prepared and shows uniform pore structure, which is because the smaller-size BC particles form smaller gaps and prevent SS from rapidly settling to its bottom during the hot-pressing, resulting in more uniform distribution (as shown in Figure 2 b).…”

Section: Resultsmentioning

confidence: 99%

Preparation of Plastics- and Foaming Agent-Free and Porous Bamboo Charcoal based Composites Using Sodium Silicate as Adhesives

Chai

Zhang

et al. 2021

Materials

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Plastics and foaming agents are often used to prepare large-size and low-density bamboo charcoal (BC) based composites. In this study, a plastic-free and foaming agent-free BC based composite was prepared by substituting sodium silicate (SS) for plastics. The effect of both the BC particle sizes and the usage amount of SS on the mechanical and adsorptive properties of the BC/SS composites were investigated. The experimental results show that when the BC particle size is 270 μm and the mass ratio of BC to SS is equal to 10:5, the BC/SS composite has the optimal foaming effect and best comprehensive properties. In addition, the foaming pores of the composite are caused by water vapor, which has difficulty escaping the BC because of the blockage of SS during the hot pressing process. In the BC/SS composite (10:5), the static bending intensity and the compressive strength reach respectively 6.13 MPa and 5.5 MPa, and the average pore size and porosity are 557.85 nm and 52.03%, respectively. In addition, its formaldehyde adsorptionrate reaches 21.6%. In view of good mechanical properties, formaldehyde adsorption, and environmentally friendly performance, the BC/SS composite has a great potential as a core layer of interior building materials.

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Geopolymerization mechanism of binder-free mine tailings by sodium silicate

Cited by 82 publications

References 54 publications

Characterization of Strength and Quality of Cemented Mine Backfill Made up of Lead-Zinc Processing Tailings

Characterization of Strength and Quality of Cemented Mine Backfill Made up of Lead-Zinc Processing Tailings

Synthesis of Si-Based High-Efficiency and High-Durability Superhydrophilic-Underwater Superoleophobic Membrane of Oil–Water Separation

Preparation of Plastics- and Foaming Agent-Free and Porous Bamboo Charcoal based Composites Using Sodium Silicate as Adhesives

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