The role of iron in the formation of inorganic polymers (geopolymers) from volcanic ash: a 57Fe Mössbauer spectroscopy study

Lemougna, Patrick N.; MacKenzie, Kenneth J.D.; Jameson, Guy N. L.; Rahier, Hubert; Melo, U. F. Chinje

doi:10.1007/s10853-013-7319-4

Cited by 122 publications

(78 citation statements)

References 32 publications

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“…The higher kaolinite content can explain the overall superior performance of the CP in comparison to the WP geopolymer pastes despite the presence of more impurities (higher Fe 2 O 3 and TiO 2 content in the form of goethite and rutile). Previous studies indicate that iron does interfere in the strength development of geopolymer 13,14 . However, it is more likely that other factors such as particle size and the mineralogical form of the iron play a more critical role in their reactivity 13,14 .…”

Section: Resultsmentioning

confidence: 95%

“…Previous studies indicate that iron does interfere in the strength development of geopolymer 13,14 . However, it is more likely that other factors such as particle size and the mineralogical form of the iron play a more critical role in their reactivity 13,14 . When viewing the geopolymers synthesized with 75% of CP, only the use of the calcined for 6 h (CP-6) resulted in a compressive strength higher than that of SG (Figure 4b).…”

Section: Resultsmentioning

confidence: 95%

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Physicochemical Characterization of Pulverized Phyllite Rock for Geopolymer Resin Synthesis

et al. 2017

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Geopolymeric materials have some unique properties such as early-high compressive strength, durability, resistance to acids and sulfates, ability to immobilize toxic and radioactive compounds, low porosity and high temperature resistance. These materials are strategic for sustainable development and are a suitable alternative to Portland cement. The use of phyllite as a geopolymer precursor is encouraged by its abundance, low cost, and the fact that it is already applied in ceramic industries as a kaolin substitute. The objective of this paper is the physicochemical characterization of geopolymeric resin using two pulverized phyllite rocks as precursors with STEM, XRD and XRF techniques. It was found that both phyllite rocks studied have a high quartz content of approximately 50% (weight), which have a "filler" function in the microstructure of the resin helping stabilize residual tensions after curing. Kaolinite and muscovite minerals are present in up to 40% (weight) and are responsible for the high compressive strength of the geopolymer resins.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 95%

Physicochemical Characterization of Pulverized Phyllite Rock for Geopolymer Resin Synthesis

et al. 2017

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“…The strength and water permeability of concretes have been improved by adding Fe 2 O 3 nanoparticles in the cement up to 4.0 wt%, with the strengthening mechanism related to the capacity of Fe 2 O 3 to act as foreign nucleation site as well as nanofillers recovering the pore structure of the specimens and accelerating the C-S-H gel formation [30,31]. observed that the amount of iron up to 12-14 wt% found in the volcanic ashes was not detrimental for the reactivity and strength development of geopolymers.…”

Section: Discussionmentioning

confidence: 99%

“…However, they noted that major part of this iron was concentrated in the crystalline phases as augite and ferroanforsterite [32]. The production of geopolymer from red mud with a high amount of iron (>30 wt%) [29,31] gives relatively low mechanical properties at an earlier stage of the geopolymerization. Geopolymers with 100% Fe designed by Bell et al [33] 2009; Wagh and Douse, 1991 [34], do not reach the complete solidification after a year of curing.…”

Section: Discussionmentioning

confidence: 99%

A Sustainable Approach for the Geopolymerization of Natural Iron-Rich Aluminosilicate Materials

et al. 2014

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Two iron-rich clayey materials (L1 and L2, with the main difference being the level of iron accumulation) have been studied for their suitability as solid precursors for inorganic polymer composites. L1, with the lower iron content, was calcined at 700°C for 4 h and used as replacement, in the range of 15-35 wt%, for both raw laterites in the formulations of geopolymeric composites. The different mixtures were activated with a highly concentrated alkaline solution containing sodium hydroxide and sodium silicate. River sand with semi-crystalline structure was added to form semi-dry pastes which were pressed to appropriate shape. X-ray diffraction, Infrared spectroscopy, Scanning Electron Microscopy and Mercury Intrusion Porosimetry results demonstrated the effectiveness of the calcined fraction of L1 to act as nucleation sites and extend the geopolymerization to the matrix composites. A highly compact matrix with low porosity and good stability in water, together with a strength comparable to that of standard concretes was obtained allowing for conclusions to be made on the quality of laterites as promising solid precursor for sustainable, environmentally-friendly, and cost-efficient structural materials.

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“…Several authors [3,25] measured relatively high quantities of Fe in the binding phase of IP; however, no structural analysis was provided therein. Lemougna et al [40] observed distorted tetrahedral or 5-coordinated site containing Fe 3? , while Perera et al [41] reported that Fe was present in IP in octahedral sites and only in samples heated up to 1173 K, iron was present in tetrahedral coordination.…”

Section: Microchemistry Of the Bindermentioning

confidence: 99%

Inorganic Polymers from a Plasma Convertor Slag: Effect of Activating Solution on Microstructure and Properties

Krisková

Machiels

Pontikes

2015

J. Sustain. Metall.

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Plasma processing of materials is a technology now also employed in the management of municipal solid wastes, often mixed with industrial residues. The specifics depend per case, but typically the process delivers energy, in the form of a gas or heat, a metal-rich fraction as well as a slag. The slag, containing mainly Si-, Fe-, Ca-and Al-oxides, is almost completely amorphous after rapid cooling and thus could possibly be used as precursor in the synthesis of inorganic polymers (IP). The latter is explored in the present work. Slag resembling the composition of refuse-derived fuel ash was mixed with various Na-silicate activating solutions, and the effect of SiO 2 /Na 2 O as well as H 2 O/Na 2 O molar ratio on the synthesis and mechanical properties of the prepared IP was investigated. It was found that for SiO 2 / Na 2 O molar ratios of 1.2 and H 2 O/Na 2 O molar ratio of 30.8, the mechanical strength of casted IP reached almost 90 MPa after 90 days. Further decrease in the SiO 2 /Na 2 O ratio, accompanied by decrease in the H 2 O/Na 2 O ratio, increased the early strength and the released reaction heat, but had no effect on the late strength. In addition to that, crack formation was pronounced. The increase of the concentration of activating solution, by means of reducing the water content level, i.e. H 2 O/Na 2 O, resulted in an increase of the released reaction heat as well as an increase of the mechanical strength, up to 112 MPa at 90 days. The above results are relevant to a range of metallurgical slags and other vitreous by-products and contribute towards more high added-value applications.

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The role of iron in the formation of inorganic polymers (geopolymers) from volcanic ash: a 57Fe Mössbauer spectroscopy study

Cited by 122 publications

References 32 publications

Physicochemical Characterization of Pulverized Phyllite Rock for Geopolymer Resin Synthesis

Physicochemical Characterization of Pulverized Phyllite Rock for Geopolymer Resin Synthesis

A Sustainable Approach for the Geopolymerization of Natural Iron-Rich Aluminosilicate Materials

Inorganic Polymers from a Plasma Convertor Slag: Effect of Activating Solution on Microstructure and Properties

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