Producing sodium silicate powder from iron ore tailings for use as an activator in one-part geopolymer binders

Figueiredo, Ricardo Augusto Martins; Brandão, Paulo Roberto Gomes; Soutsos, Marios; Henriques, Andréia Bicalho; Fourie, Andy; Mazzinghy, Douglas Batista

doi:10.1016/j.matlet.2021.129333

Cited by 33 publications

(14 citation statements)

References 11 publications

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“…WG-based activator gave lower early strength (1-day) but equal or superior 7 and 28-day strengths than the commercially available activating solutions. Since the method was proposed, it has been replicated and verified by several researchers (see, e.g., [16]), using other silicate sources (e.g., [17,18]), and providing environmental analysis confirming a potential for a 70% reduction in CO 2 emissions when compared to Portland cement-based concrete [19,20]. However, a detailed investigation of the microstructure of the reaction products when a WG-based activator is used has not been carried out yet.…”

Section: Introductionmentioning

confidence: 98%

Chemical and Microstructural Properties of Fly Ash and Fly Ash/Slag Activated by Waste Glass-Derived Sodium Silicate

Bondar¹,

Vinai

2022

Crystals

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Sodium silicate is commonly used for activating alumina silicates to produce alkali-activated binders that can compete with conventional Portland cement in concrete. However, the cost and emissions related to activators can hinder the use of alkali-activated materials in the industry. The novel, waste-based activators have been developed in the last years, using Si-rich waste streams. Processing waste glass cullet not only reduces the glass landfill disposal but also allows the production of sodium silicate for alkali activation. In this article, the chemical and microstructural properties of neat fly ash and blended 60 fly ash/40 slag pastes activated by sodium silicate produced from glass cullet were studied and compared to equivalent ones activated by commercially available sodium silicate and sodium hydroxide solutions. Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) were used to determine the microstructure and composition of the gel phase. Findings have confirmed that pastes activated by the processed waste glass showed chemical and microstructural properties comparable to pastes produced with commercially available activators.

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Section: Introductionmentioning

confidence: 98%

Chemical and Microstructural Properties of Fly Ash and Fly Ash/Slag Activated by Waste Glass-Derived Sodium Silicate

Bondar¹,

Vinai

2022

Crystals

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“…In the iron ore beneficiation process, two types of tailings are produced: the mud, rich in iron, resulting from the desliming process, and the sandy tailings, a sand rich in quartz, resulting from the tailings flotation process. 7 Among the various applications for iron-rich mud, we can mention: Prates et al 8 used the tailings from iron mining for the synthesis of a heterogeneous acid catalyst to produce biodiesel. Silva 9 also used them as a catalyst, but for the production of carbon nanomaterials applied in the adsorption of contaminants, while Luciano et al 10 used the tailings as a source of iron to promote thermal decomposition of organic compounds to obtain biofuels.…”

Section: Introductionmentioning

confidence: 99%

“…As for the sandy tailings, rich in quartz, some examples of applications are in the replacement of sand for production of concrete and mortars, production of ceramics, synthesis of silicates and production of geopolymers. 5,7,11,12 Geopolymers can be defined as inorganic polymers obtained by the alkaline activation of aluminosilicates at low temperatures. They are constituted by a threedimensional network in which the silicon atoms alternate with those of aluminum in tetrahedral coordination, sharing all the oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, sodium silicate can also be produced from sandy tailings, due to the silica-rich composition of the tailing. 7 The conventional process of producing sodium silicate is via calcination of a mixture of sodium carbonate (Na 2 CO 3 ) and natural quartz sand (SiO 2 ) at 1400-1500 °C, leading to high energy consumption, maintenance cost and contaminant emission dust and CO 2 . 22 Therefore, the production of sodium silicate through alternative routes is of great importance.…”

Section: Introductionmentioning

confidence: 99%

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Use of Iron Ore Tailing as Raw Material for Two Products: Sodium Silicate and Geopolymers

Prates¹,

Lima²,

Ferreira³

et al. 2023

J. Braz. Chem. Soc.

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In this work, iron ore tailing (IOT) was used for the production of two different materials: sodium silicate and geopolymers. Initially, reactions of IOT with NaOH were carried out by hydrothermal reaction in autoclave at 200 °C (1:1.5 and 1:2.5 SiO2:NaOH molar ratio) and reaction times of 4 and 8 h. X-ray fluorescence by dispersive energy (XRF), X-ray diffraction (XRD), Mössbauer spectroscopy, scanning electron microscopy (SEM-EDS) and titrations showed that IOT:NaOH ratios of 1:2.5 and reaction time 8 h completely dissolved the quartz from the IOT, obtaining a solid fraction consisting mainly of hematite and an aqueous phase of sodium silicate, which showed contents of ca. 23% SiO2 and 19% Na2O. This sodium silicate obtained was then combined with IOT (25 and 50 wt.%) to produce geopolimeric material with excellent physicochemical properties, fast curing time and very good compressive strength results, which ranged from 41 to 58 MPa and many potential applications.

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“…[8][9][10] Several sources of waste-derived silicates have been investigated in the literature for their use as activators. 11 Mining waste such as iron ore tailings, 12 glass waste, 7,13 and silica fume 14,15 are among the inorganic Si-rich waste streams successfully utilized for the production of activators for AAM.…”

Section: Introductionmentioning

confidence: 99%

Bio‐derived sodium silicate for the manufacture of alkali‐activated binders: Use of bamboo leaf ash as silicate source

Vinai

Ntimugura

Cutbill

et al. 2022

Int J Applied Ceramic Tech

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Alkali activated binders are a promising alternative to the use of Portland cement in the manufacture of concrete for curbing CO2 emissions. Novel sources of silicates have been investigated in recent years for reducing cost and environmental impacts associated with the use of chemical activators. This study describes the production of solid sodium silicate (SS) activating powder from bamboo leaf ash (BLA). Bamboo leaves were calcined at 550–800°C, mixed with NaOH pellets, and heated in an oven at 300°C. The obtained silicate powder was used for activating blended fly ash/slag samples. Mechanical and microstructural properties of BLA‐based samples were compared to those of samples made with commercially available chemicals. The strength of BLA‐activated mortars matched the commercially‐sourced activators, being 25–30 MPa at 7 days and exceeding 40 MPa at 28 days. The microstructural analysis suggested that BLA‐based SS showed a lesser degree of dissolution of precursors at 7 days, but the quality of the matrix was higher than that of NaOH‐activated samples. These results confirmed that the reactivity of BLA‐silicate powder was similar to that of commercial SS solutions, and show the potential valorization of future biomass renewable waste in the production of low carbon, alkali‐activated concretes.

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Producing sodium silicate powder from iron ore tailings for use as an activator in one-part geopolymer binders

Cited by 33 publications

References 11 publications

Chemical and Microstructural Properties of Fly Ash and Fly Ash/Slag Activated by Waste Glass-Derived Sodium Silicate

Chemical and Microstructural Properties of Fly Ash and Fly Ash/Slag Activated by Waste Glass-Derived Sodium Silicate

Use of Iron Ore Tailing as Raw Material for Two Products: Sodium Silicate and Geopolymers

Bio‐derived sodium silicate for the manufacture of alkali‐activated binders: Use of bamboo leaf ash as silicate source

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