Preparation of high-performance silico-aluminophosphate geopolymers using fly ash and metakaolin as raw materials

Guo, Haozhe; Zhang, Baifa; Deng, Liangliang; Yuan, Peng; Li, Mengyuan; Wang, Qiang

doi:10.1016/j.clay.2021.106019

Cited by 58 publications

(24 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a phosphate acid environment, the Al oxides will be dissolute after the Ca compounds; therefore, the C–P–H gel will be formed before Al-P [ 10 ]. Therefore, by comparing the samples with MK against those without MK, it can be stated that the samples with higher Ca content will exhibit a lower setting time, due to the solubility differences between the divalent metals and the trivalent one.…”

Section: Resultsmentioning

confidence: 99%

“…The broad peak at 27° (2θ) indicates the formation of the berlinite phase (AlPO 4 ) which has a similar XRD pattern to quartz and will confer high mechanical properties to the final geopolymer [ 10 , 26 ]. Moreover, by comparing the XRD pattern of the MK with that of MK–geo, it can be observed that all of the peaks between at 26° (2θ) and 35° (2θ) appeared due to the reaction between the acid and the raw material.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, recent studies in the field have been focused on the discovery and development of new activation solutions which are cheap and have a low environmental impact. Thus, phosphoric acid has become the main competitor of alkaline activators used to date in geopolymers [ 10 , 11 ]. However, the replacement of alkaline solutions with phosphoric acid has led to a major change in the formation mechanism of geopolymers; therefore, the obtained materials may have chemical, structural, thermal and mechanical characteristics which are different from those of alkaline-activated geopolymers.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

et al. 2021

View full text Add to dashboard Cite

Coal ash-based geopolymers with mine tailings addition activated with phosphate acid were synthesized for the first time at room temperature. In addition, three types of aluminosilicate sources were used as single raw materials or in a 1/1 wt. ratio to obtain five types of geopolymers activated with H3PO4. The thermal behaviour of the obtained geopolymers was studied between room temperature and 600 °C by Thermogravimetry-Differential Thermal Analysis (TG-DTA) and the phase composition after 28 days of curing at room temperature was analysed by X-ray diffraction (XRD). During heating, the acid-activated geopolymers exhibited similar behaviour to alkali-activated geopolymers. All of the samples showed endothermic peaks up to 300 °C due to water evaporation, while the samples with mine tailings showed two significant exothermic peaks above 400 °C due to oxidation reactions. The phase analysis confirmed the dissolution of the aluminosilicate sources in the presence of H3PO4 by significant changes in the XRD patterns of the raw materials and by the broadening of the peaks because of typically amorphous silicophosphate (Si–P), aluminophosphate (Al–P) or silico-alumino-phosphate (Si–Al–P) formation. The phases resulted from geopolymerisation are berlinite (AlPO4), brushite (CaHPO4∙2H2O), anhydrite (CaSO4) or ettringite as AFt and AFm phases.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

et al. 2021

View full text Add to dashboard Cite

show abstract

“…This increase in peak intensity was most likely due to the contribution due to the layered orientation of the mullite grain stacking (related to preferred orientation) which is a common occurrence during the sample preparation. Moreover, this also indicates that mentioned crystalline phases did not participate in geopolymerization reaction in GP sample [ 33 ]. Diffraction peaks intensities of similar crystalline phases in GP1 and GP2 samples are much lower than in GP sample.…”

Section: Resultsmentioning

confidence: 99%

Potential Usage of Hybrid Polymers Binders Based on Fly Ash with the Addition of PVA with Satisfying Mechanical and Radiological Properties

Mirković

Kljajević

Dolenec

et al. 2021

Gels

View full text Add to dashboard Cite

Since recycled technologies usage is mandatory for environmental safety, and in this regard, it is important to examine new materials that can be used in construction and are primarily produced from fly ash. In addition to characteristics such as hardness and compressive strength, the given materials must also be radiologically and environmentally safe. The main concept of engineered geopolymer gel composites based on fly ash residues is focused on developing binder materials via gel formation processes that can replace ordinary cement materials. This study is unique in researching the potential use of fly ash from the Nikola Tesla thermal power plant in Serbia, where the hybrid geopolymeric materials synthesized from fly ash are experimentally examined with the addition 1 wt% and 2 wt% of polyvinyl alcohol (PVA). This paper aims to investigate the structural, morphological, mechanical, and radiological properties of hybrid materials with the addition of PVA and without additive in the period of ageing for 28 days at room temperature. The phase composition was investigated using X-ray powder diffraction (XRPD) analysis, while morphological characteristics of these materials were examined using scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDS). Vibrational spectra of obtained samples are investigated using diffuse reflectance infrared Fourier transform (DRIFT) and Fourier transform infrared (FTIR) techniques. The hardness and compressive strength are also examined, indicating that the 1 wt% addition in geopolymeric matrix results in the best mechanical properties. Radiological measurements of investigated all geopolymer samples show decreasing activity concentrations of radionuclides for 50% compared to fly ash.

show abstract

“…That was conrmed by the DSC curves and also agrees with literature that showed the crystallization of the aluminophosphate phase indicating that it stands as the major phase beside others in the phosphate geopolymer binder. 32,33 When looking closely at the range of atomic ratio Si/P, one can distinguish two types of the composition of the silicoaluminophosphate phase based on the silicon content. Those with the atomic ratios Si/P < 0.5 imply a silica poor silico-aluminophosphate phase, whereas the atomic ratios Si/P > 0.5 correspond to the silica-rich silico-aluminophosphate phase.…”

Section: Microstructurementioning

confidence: 99%

Preparation of acid aluminum phosphate solutions for metakaolin phosphate geopolymer binder

Djobo

Nkwaju

2021

RSC Adv.

View full text Add to dashboard Cite

show abstract

Preparation of high-performance silico-aluminophosphate geopolymers using fly ash and metakaolin as raw materials

Cited by 58 publications

References 55 publications

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

Potential Usage of Hybrid Polymers Binders Based on Fly Ash with the Addition of PVA with Satisfying Mechanical and Radiological Properties

Preparation of acid aluminum phosphate solutions for metakaolin phosphate geopolymer binder

Contact Info

Product

Resources

About