Reaction kinetics and kinetics models of alkali activated phosphorus slag

Xie, Fuzhu; Liu, Ze; Zhang, Dawang; Wang, Jixiang; Huang, Tianyong; Wang, Dongmin

doi:10.1016/j.conbuildmat.2019.117728

Cited by 32 publications

(7 citation statements)

References 38 publications

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“…The retarding effect of soluble Si on dissolution of slag then slowed down the reaction kinetics of sodium silicate activated slag, resulting in an induction period during the reaction process as shown in Figure 3b. The induction period has been also widely detected through isothermal calorimetry measurements by many studies in the literature [20][21][22][25][26][27][28]. Besides the reaction kinetics, the effect of soluble Si by slowing down the dissolution of slag also affects the microstructure formation.…”

Section: Dissolution Resultsmentioning

confidence: 99%

“…According to the aforementioned calorimetric studies, among others in the literature like [25][26][27][28], an obvious different calorimetric characteristic can be found between the NaOH activated slag paste and the sodium silicate activated slag paste. As shown in Figure 1, the heat evolution rate curve of NaOH activated slag paste demonstrates no induction period, while that of sodium silicate activated slag paste show an obvious induction period.…”

Section: Introductionmentioning

confidence: 99%

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Preliminary Interpretation of the Induction Period in Hydration of Sodium Hydroxide/Silicate Activated Slag

Zuo

2020

Materials

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Many calorimetric studies have been carried out to investigate the reaction process of alkali-activated slag paste. However, the origin of the induction period and action mechanism of soluble Si in the dissolution of slag are still not clear. Moreover, the mechanisms behind different reaction periods are not well described. In this study, the reaction kinetics of alkali-activated slag paste was monitored by isothermal calorimetry and the effect of soluble Si was investigated through a dissolution test. The results showed that occurrence of the induction period in hydration of alkali-activated slag paste depended on the presence of soluble Si in alkaline activator and the soluble Si slowed down the dissolution of slag. A dissolution theory-based mechanism was introduced and applied to the dissolution of slag, showing good interpretation of the action mechanism of soluble Si. With this dissolution theory-based mechanism, origin of the induction period in hydration of alkali-activated slag was explicitly interpreted.

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Section: Dissolution Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Preliminary Interpretation of the Induction Period in Hydration of Sodium Hydroxide/Silicate Activated Slag

Zuo

2020

Materials

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“…The modulus of water glass has great influences on early hydration and compressive strength of alkali-activated phosphorus slag cement [31]. The blended activator of water glass and NaOH is also recommended to be used for phosphorus slag [32]. Rheological behaviors of activated phosphorus slag are strengthened by another blended activator of Ca(OH) 2 and Na 2 SO 4 [33].…”

Section: Introductionmentioning

confidence: 99%

Influence of Phosphorus Slag on Physical and Mechanical Properties of Cement Mortars

et al. 2020

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Influences of phosphorus slag from 10% to 50% (by mass) on the setting time and the water requirement of the normal consistency of cement pastes, flowability, resistance to carbonation, and the compressive strength of cement mortars were investigated. The physical activation by improving fineness and the chemical activation by adding the chemical activator were evaluated by the compressive strength of cement mortars with 30% by mass of phosphorus slag. Hydration heat, X-ray diffraction, and scanning electron microscopy were used to study the microstructure of cement pastes and mortars with 30% by mass of phosphorus slag and the chemical activator. Results showed that the setting time of cement pastes was delayed by phosphorus slag from 10% to 50%. Phosphorus slag had nearly no effects on the water requirement of the normal consistency of cement pastes and the flowability of cement mortars. The resistance to carbonation of cement mortars was decreased by phosphorus slag from 10% to 50% according to the acceleration carbonation. The compressive strength of cement mortars was also decreased by phosphorus slag from 10% to 50% and the low activity of phosphorus slag was concluded based on compressive strength of cement mortars. The effect of the chemical activator on the compressive strength of cement mortars with 30% by mass of phosphorus slag was better than improving fineness of phosphorus slag from 300 m2/kg to 450 m2/kg. Both hydration heat and cement hydrates were inhibited by phosphorus slag and could be partly compensated by the chemical activator. Loose morphology and propagations of microcracks were found in cement pastes and mortars with 30% by mass of phosphorus slag.

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“…Liu et al [ 10 , 15 ] and Mehdizadeh et al [ 16 ] investigated, in some detail, the rheological properties and microstructure of fresh slurries of alkali-activated phosphorus slag-based geopolymer. In addition, the reaction kinetics of alkali-activated phosphorus slag-based geopolymer was also scrutinized and kinetic models were constructed by Liu et al [ 17 ]. However, phosphorus slag is a material lacking the aluminum phase, which is an important element in the composition of geopolymer gels.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ultrafine Fly Ash and Water Glass Content on the Performance of Phosphorus Slag-Based Geopolymer

Yang

et al. 2022

Materials

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Phosphorus slag (PS), an industrial waste slag, has been used in geopolymers because it is rich in silicon and calcium. The poor performance of phosphorus slag-based geopolymer is due to its aluminum deficiency. In this work, low-calcium fly ash, treated by a wet-grinding process, named wet-grinding ultrafine fly ash (WUFA) was used as an Al supplement to replace some of the phosphorus slag, and the wet-grinding, ultrafine fly ash-phosphorus slag (WUFA-PS)-based geopolymer was prepared. The effects of the substitution amount of WUFA and the activator dosage on the hydration properties, mechanical properties, pore structure and SEM of the WUFA-PS geopolymer were discussed in detail. The results indicate that WUFA and more activators contribute to the Al and high alkalinity environment, which positively induces the production of more geopolymer gels, thus releasing more heat and optimizing the pore structure of the matrix. The compressive strength increased by up to 28.1%. The enhanced performance of the WUFA-PS-based geopolymer may also arise from the filling effect and activity improvement of WUFA. This study has proved the feasibility of preparing a geopolymer by blending wet-grinding ultrafine fly ash and phosphorus slag and has provided references for the ratio and performance evaluation of WUFA-PS-based geopolymer concrete.

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Reaction kinetics and kinetics models of alkali activated phosphorus slag

Cited by 32 publications

References 38 publications

Preliminary Interpretation of the Induction Period in Hydration of Sodium Hydroxide/Silicate Activated Slag

Preliminary Interpretation of the Induction Period in Hydration of Sodium Hydroxide/Silicate Activated Slag

Influence of Phosphorus Slag on Physical and Mechanical Properties of Cement Mortars

Effect of Ultrafine Fly Ash and Water Glass Content on the Performance of Phosphorus Slag-Based Geopolymer

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