Effect of silicate modulus on the setting, mechanical strength and microstructure of iron-rich aluminosilicate (laterite) based-geopolymer cured at room temperature

Kaze, Cyriaque Rodrigue; Djobo, Jean Noël Yankwa; Nana, Achile; Tchakouté, Hervé K.; Kamseu, Elie; Melo, Uphie Chinje; Leonelli, Cristina; Rahier, Hubert

doi:10.1016/j.ceramint.2018.08.205

Cited by 106 publications

(48 citation statements)

References 40 publications

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“…As mentioned earlier, the only parameter that varied significantly in our tests was the molarity of the NaOH solution, whereas the wt% addition of Na 2 SiO 3 was kept equal in all tests and the L/S ratio in the reactive paste was very low. Prolonged ageing periods normally improve compressive strength [2,44], but in our study this was not the case even when different mixing configurations were used (data not shown). presence of sufficient OΗ − , which accelerate polycondensation, whereas if ratios get bigger than a specific value, the compressive strength will drop.…”

Section: Slag Characterisationcontrasting

confidence: 54%

“…Optimum ratios indicate the presence of sufficient OH − , which accelerate polycondensation, whereas if ratios get bigger than a specific value, the compressive strength will drop. As mentioned in a recent study and several other research works, an optimum Na/Al ratio close to one is required for the synthesis of IPs with high strength [44]. Regarding the effect of the molar ratio Fe 2 O 3 /Na 2 O, it is seen from Table 2 that obviously this ratio decreases as the molarity of NaOH solution increases.…”

Section: Slag Characterisationmentioning

confidence: 63%

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Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

et al. 2019

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In this study, the alkali activation potential of a Polish ferronickel slag (PS), for the production of inorganic polymers (IPs), is investigated. The effect of the main synthesis parameters, i.e., strength of the activating solution, consisting of NaOH and Na2SiO3 solutions and affecting (SiO2 + Al2O3)/Na2O and other important molar ratios in the reactive paste, pre-curing period, curing temperature and time and ageing period was investigated. The structural integrity of the produced specimens was tested after their (i) immersion in distilled water and acidic solutions for a period of 7–30 days, and (ii) firing at temperatures between 200 °C and 1000 °C. Several analytical techniques including X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, Differential scanning analysis-Thermogravimetry and Scanning Electron Microscopy were used for the characterization of the produced IPs. Results show that under the optimum synthesis conditions the IPs obtain compressive strength that exceeds 65 MPa. An innovative aspect of this study is that after heating at 400 °C, the specimens acquire compressive strength of 115 MPa and this indicates that they can be also used as fire resistant materials. This study highlights the potential of alkali activation for the valorization of a ferronickel slag and the production of IPs that can be used as binders or in several construction applications, thus improving the sustainability of the metallurgical sector.

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Section: Slag Characterisationcontrasting

confidence: 54%

Section: Slag Characterisationmentioning

confidence: 63%

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

et al. 2019

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“…The SiO 2 content in the residue is high, and its activity is high as well. It can be used as a raw material to prepare silicon-based products, such as zeolite, tobermorite, xonotlite, and geopolymers [5,[42][43][44]. Figure 14 shows the SEM images of CFA and the residue after calcination at 230 • C at different durations.…”

Section: Sem and Eds Resultsmentioning

confidence: 99%

Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

Guo

Zou

et al. 2019

Minerals

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Owing to the depletion of bauxite and increasing demand for alumina, calcination methods for extracting alumina from coal fly ash (CFA) were developed. However, these methods have disadvantages such as the need for high temperatures and the emission of toxic gases. Hence, in this study, Al2O3 was extracted from CFA via low-temperature potassium bisulfate calcination technology. Effects of the potassium bisulfate amount, calcination temperature, and calcination time on the alumina extraction efficiency were investigated using X-ray diffraction, thermal gravimetry, scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectroscopy. It was found that this technique could recover alumina efficiently, and potassium bisulfate significantly contributed to the degradation of mullite and corundum phases. Al2O3 in CFA was converted into soluble K3Al(SO4)3. With a KHSO4/Al2O3 molar ratio of 7:1, calcining temperature of 230 °C, and calcining time of 3 h, the alumina extraction efficiency reached a maximum of 92.8%. The Avrami–Erofeev equation showed the best fit with the kinetic data for the low-temperature calcination of CFA with KHSO4. The activation energy was 28.36 kJ/mol.

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“…However, the results show that the specimen synthesised with 40% to binder to aggregate ratio had the broad band frequency around 300 cm − 1 to 500 cm − 1 . This broad band is related to quartz mineral [44].…”

Section: Ftir Analysis Of Specimens With Different Binder Contentmentioning

confidence: 88%

“…The results show that specimens had little or insigni cant amount of water within the matrix due to lack of H-O-H vibrations around 3600 cm-1 [43]. The absorption bands around 500 cm − 1 usually indicates the bending mode of Si-O-T (T may be Al or Si and in some cases Ca) [44]. The band frequency of the sample with 20 % binder to aggregate ratio around 300 cm − 1 to 500 cm − 1 was low, suggesting that the formation of geopolymer products was inversely proportional to the band frequency.…”

Section: Ftir Analysis Of Specimens With Different Binder Contentmentioning

confidence: 97%

Enhancement of Waste Foundry Sand Mechanical Properties Through Stabilization Using Slag Based Geopolymer Binder

Sithole

Mashifana

Tsotetsi

2021

Preprint

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It is of paramount importance to minimize carbon emission generated from production of major building and construction materials used worldwide such as bricks and Ordinary Portland cement to achieve sustainability requirements. In this paper, the binding properties of the synthesized granulated blast furnace slag (GBFS) geopolymers were assessed by developing eco-friendly waste foundry sand bricks. Four different mix designs were prepared by blending GBFS based geopolymer binder with aggregates (waste foundry sand and crushed stones). The amount of GBFS geopolymer binder was varied from 0 to 40 %. The developed specimens were evaluated for mechanical properties, durability, structural performance, and environmental impact. The specimens synthesised with 40 % GBFS geopolymer binder at a L/ S ratio of 15 % and cured at 80 ℃ achieved the highest UCS of 12 MPa. The results showed that the developed specimens are acid resistant which suggest that they can be used in corrosive environments and do not pose any threat of environmental pollution for long-term use. In conclusion, GBFS-based geopolymers can be used as binders to fabricate building bricks that meet the minimum requirement of ASTM C62-10 that can be used in negligible weathering conditions.

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Effect of silicate modulus on the setting, mechanical strength and microstructure of iron-rich aluminosilicate (laterite) based-geopolymer cured at room temperature

Cited by 106 publications

References 40 publications

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

Enhancement of Waste Foundry Sand Mechanical Properties Through Stabilization Using Slag Based Geopolymer Binder

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