Investigation of Phosphate based geopolymers formation mechanism

Zribi, M.; Baklouti, Samir

doi:10.1016/j.jnoncrysol.2021.120777

Cited by 47 publications

(14 citation statements)

References 29 publications

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“…A new peak formed at the chemical shift between 0 and −20 ppm, which is the characteristic peak of phosphate-based geopolymer, corresponding to Al VI in Al(OP) 6−x (SiO) x [ 33 ]. According to previous studies, this deconvolution reveals the presence of two resonances [ 34 ]. The resonance located at −12 ppm is attributed to Al VI in condensed aluminosilicate networks and the other one located at −18 ppm is assigned to Al VI in polymerized phosphate aluminum networks.…”

Section: Resultsmentioning

confidence: 82%

Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst

Qian

Zhang

2022

Gels

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As a common industrial by-product, the spend fluid catalytic-cracking (SFCC) catalyst was used to prepare phosphate-based geopolymer for the first time. The structure and property of geopolymer with phosphoric acid concentration ranging from 6 to 14 mol/L was characterized by compressive strength measurements, X-ray powder diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and 27Al and 29Si nuclear magnetic resonance (NMR). A stable binder was formed with the compressive strength in the range of 9.8 to 30.2 MPa when the acid concentration was between 6 and 12 mol/L. The higher concentration of acid can promote the dissolution of raw materials and formation of geopolymer gels. The coordination of silicon and aluminum in geopolymer gel synthesized with the SFCC catalyst and metakaolin is similar. Compared with the geopolymer with metakaolin, which forms more Si-O-Al bonds, in the networks of geopolymer with the SFCC catalyst, more Si(Al)-O-P bonds were formed. These results indicate that the SFCC catalyst can be an excellent raw material for the synthesis of phosphate-based geopolymer.

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Section: Resultsmentioning

confidence: 82%

Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst

Qian

Zhang

2022

Gels

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“…We notice the disappearance of phases like kaolinite, illite, montmorillonite and the appearance of others like anorthite and mullite as a consequence of a series of physic‐chemical transformations occurred 40,41 . The densification of mixtures proceeded through a viscous sintering (by melt flow) due to the apparition of amorphous phase, which is clearly shown by a diffuse reflection on diffractogram shapes (broad hump between 18 and 40°) 42,43 . From the identification of XRD patterns, we notice the apparition of anorthite in all mixture except sample number 3 and 3* composed by 100% kaolin.…”

Section: Resultsmentioning

confidence: 87%

“…40,41 The densification of mixtures proceeded through a viscous sintering (by melt flow) due to the apparition of amorphous phase, which is clearly shown by a diffuse reflection on diffractogram shapes (broad hump between 18 and 40 • ). 42,43 From the identification of XRD patterns, we notice the apparition of anorthite in all mixture except sample number 3 and 3* composed by 100% kaolin. Mullite phase appears in all mixtures containing kaolin (K).…”

Section: Mineralogical Analysis By X-ray Diffractionmentioning

confidence: 88%

Study of clay's mineralogy effect on mechanical properties of ceramic body using an experimental design

Ayadi

Baklouti

Kammoun

et al. 2021

Int J Applied Ceramic Tech

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Three clays minerals namely illite (I), montmorillonite (M), and kaolin (K) were chosen as references to study the effect of mixture composition of clays on the mechanical properties and the shrinkage of the fired ceramic. The study was accomplished using the experimental design methodology. More specifically, a mixture design was carried out in order to establish relationships between mechanical strength and shrinkage of finished products and the proportions of the three clay mineral references in the mixture. The statistical study shows that the fitted models were adequate to describe these properties of fired ceramic bodies. The results demonstrate that the mechanical resistance was mainly governed by the amount of montmorillonite mineral. In fact, the mixture design performed in this study shows clearly that montmorillonite can be incorporated in industrial ceramic products up to 45 wt% with high mechanical resistance. On the other hand, the shrinkage decreases strongly with the amount of kaolin in the mixture and increases with the amount of illite while montmorillonite exhibits moderate effect on this property. The higher strength was shown in mixture in which mullite and anorthite appear together due to the presence of kaolinite and illite and give, as a consequence, a synergic power.

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“…In the published literature, we have noticed that some scholars have used room temperature in their studies [ 29 , 48 ], while most others have used elevated temperature curing. The main heating range is between 40 °C and 90 °C, such as 40 °C [ 23 ], 60 °C [ 17 , 19 , 41 , 49 , 50 ], 80 °C [ 51 , 52 , 53 ], and 90 °C [ 54 ]. There is no obvious promoting effect when the heating temperature is too low, and if the heating temperature is too high, it may lead to the cracking of the geopolymer structure or transformation into other types of materials, such as zeolite [ 1 , 55 ].…”

Section: The Preparation Process Of Asp Geopolymersmentioning

confidence: 99%

“…At present, with regard to research on the reaction mechanism of ASP geopolymers, scholars have generally divided the geopolymerization process of ASP geopolymers into three or even four steps with depolymerization (the dealumination process) and condensation as the core [ 20 , 25 , 49 ]. The mainstream geopolymerization schematic diagram is shown in Figure 5 , and the mainstream geopolymerization process is as follows: The first is the dealumination process of the aluminosilicate precursor.…”

Section: The Preparation Process Of Asp Geopolymersmentioning

confidence: 99%

Comprehensive Understanding of Aluminosilicate Phosphate Geopolymers: A Critical Review

Zhang

Liu

2022

Materials

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Aluminosilicate phosphate (ASP) geopolymers are a new kind of green cementitious materials synthesized from aluminosilicate precursors and acidic activators (phosphoric acid or phosphate), which have received extensive attention from researchers because of their excellent and unique characteristics. The current investigation indicates that ASP geopolymers have the characteristics of a low-carbon synthesis process, high mechanical properties (e.g., the highest compressive strength can reach 146 MPa), a strong heat resistance (e.g., withstanding a high temperature of 1500 °C), and excellent dielectric properties. These excellent properties make them have broad application prospects in the fields of new building materials, coating materials, insulating materials, and heavy metal curing. Based on the research findings of approximately 85 relevant literatures on ASP geopolymers in past decades, this paper focuses on the latest research progress of ASP geopolymers from the perspectives of synthesis processes, performances, modifications, and application developments. In addition, this study summarizes the key problems existing in the current research of ASP geopolymers and suggests their possible applications in the future, which will help to provide directions for further research activities of relevant researchers.

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Investigation of Phosphate based geopolymers formation mechanism

Cited by 47 publications

References 29 publications

Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst

Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst

Study of clay's mineralogy effect on mechanical properties of ceramic body using an experimental design

Comprehensive Understanding of Aluminosilicate Phosphate Geopolymers: A Critical Review

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