Properties of coal gangue-Portland cement mixture with carbonation

Qin, Ling; Gao, Xiaojian

doi:10.1016/j.fuel.2019.02.067

Cited by 148 publications

(32 citation statements)

References 50 publications

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“…e hydration products were characterized with 29 Si MAS NMR. It was reported that six peaks were found in NMR spectrum of hydrated cement-FA paste [12,38,39]; Q 1 and Q 2 represented the chain-end Si-O tetrahedrons and middle-chain Si-O tetrahedrons in hydration products; Q 2 (1Al) denoted the middle-chain groups where one of the adjacent tetrahedral sites was occupied by Al 4+ ; Q 0 , Q 3 , and Q 4 represented the Si-O tetrahedrons in unhydrated cement minerals and Si-O tetrahedrons in FA, respectively. A Bruker Advance III400 spectrometer was adopted to carry out 29 Si-NMR (solid-state nuclear magnetic resonance), operating at 79.5 MHz, with rotation frequency of 5 kHz and the delay time of 10 s. Tetramethylsilane was used as 29 Si standard.…”

Section: Nmrmentioning

confidence: 99%

Effect of Nanosilica on Impermeability of Cement‐Fly Ash System

Liu

Zhang

Tong

et al. 2020

Advances in Civil Engineering

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Surface protection has been accepted as an effective way to improve the durability of concrete. In this study, nanosilica (NS) was used to improve the impermeability of cement-fly ash system and this kind of material was expected to be applied as surface protection material (SPM) for concrete. Binders composed of 70% cement and 30% fly ash (FA) were designed and nanosilica (NS, 0–4% of the binder) was added. Pore structure of the paste samples was evaluated by MIP and the fractal dimension of the pore structure was also discussed. Hydrates were investigated by XRD, SEM, and TG; the microstructure of hydrates was analyzed with SEM-EDS. The results showed that in the C-FA-NS system, NS accelerated the whole hydration of the cement-FA system. Cement hydration was accelerated by adding NS, and probably, the pozzolanic reaction of FA was slightly hastened because NS not only consumed calcium hydroxide by the pozzolanic reaction to induce the cement hydration but also acted as nucleation seed to induce the formation of C-S-H gel. NS obviously refined the pore structure, increased the complexity of the pore structure, and improved the microstructure, thereby significantly improving the impermeability of the cement-FA system. This kind of materials would be expected to be used as SPM; the interface performance between SPM and matrix, such as shrinkage and bond strength, and how to cast it onto the surface of matrix should be carefully considered.

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Section: Nmrmentioning

confidence: 99%

Effect of Nanosilica on Impermeability of Cement‐Fly Ash System

Liu

Zhang

Tong

et al. 2020

Advances in Civil Engineering

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“…At present, the major application fields of CG are brick making, concrete production, cement production, roadbed production, power generation, and metal recovery. [11][12][13][14][15][16][17][18][19] However, CG applied as filler into polymer matrix is also a potential means that has received less attention before.…”

Section: Introductionmentioning

confidence: 99%

Impact of titanate coupling agent on properties of high density polyethylene composite filled with coal gangue

Ding

Zhang

et al. 2020

Surface & Interface Analysis

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In this study, surface modification of coal gangue (CG) was performed with titanate coupling agent 201 (isopropyl tri(dioctylpyrophosphate) titanate), and the effects of surface modifier on mechanical properties and thermal stability of high‐density polyethylene filled with CG (HDPE/CG) and high‐density polyethylene filled with modified CG (HDPE/mCG) composites were investigated. The coupling agent was successfully grafted on CG surface through chemical reaction according to the analyses of Fourier transform infrared spectroscopy (FT‐IR) and X‐ray photoelectron spectroscopy (XPS), and the coupling agent can effectively enhance the hydrophobicity of surface that was verified by water contact angle beyond 90° of modified CG sample. With the introduction of coupling agent, some enhancements of tensile strength, flexural strength, and impact strength were observed in HDPE/mCG compared with HDPE/CG, due to the improved compatibility between mCG fillers and matrix. The increased storage modulus and decreased loss factor of HDPE/mCG composite further confirm the stronger interface adhesion after modification. Moreover, it is found that titanate coupling agent 201 can improve the thermal stability of HDPE/mCG composite to some extent.

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“…Thus, the developing technologies for the utilization of coal gangue has attracted wide attention over these years. [4][5][6][7] However, the coal gangue utilization mode is single; the research mainly focus on applications in filling in the mining area, land reclamation, production of building materials, and power generation, 8 while the application in high-value chemical products is limited.…”

Section: Introductionmentioning

confidence: 99%

“…The “13th Five‐Year” Plan has given emphasis to the technological innovation and green development in China's coal industry; it clears that more attention should be paid to the governance and utilization of coal gangue with the principle of reduction, reuse, and recycling. Thus, the developing technologies for the utilization of coal gangue has attracted wide attention over these years 4‐7 . However, the coal gangue utilization mode is single; the research mainly focus on applications in filling in the mining area, land reclamation, production of building materials, and power generation, 8 while the application in high‐value chemical products is limited.…”

Section: Introductionmentioning

confidence: 99%

Novel design of microsphere adsorbent for efficient heavy metals adsorption

Wang

Liu

Rong

et al. 2020

Int J Applied Ceramic Tech

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The fabrication of high‐efficiency and low‐cost adsorbent for the wastewater treatment is a challenging task. In this study, a hollow sphere adsorbent was synthesized from solid waste coal gangue through a facile spray drying method and subsequent calcination. The structure of the synthesized coal gangue microsphere (CM) have been characterized by multimethods including X‐ray diffraction, scanning electron microscope, Fourier transform infrared, and others. The factors influencing the adsorption for Cu2+ and Pb2+ by CM were also investigated systemically; pH between 6 and 8 was found to be optimal for Cu2+ and Pb2+ adsorption. The isotherm and kinetic analysis reveal that the adsorption process could be well represented by Langmuir and pseudo–second‐order model with a higher R2 and low χ2 value. According to Langmuir model, the maximum adsorption capacity was calculated to be 6.570 and 18.904 mg/g for Cu2+ and Pb2+ at 25°C, respectively. The adsorption mechanism was proposed to contain not only the surface reaction process, but also the diffusion process. Consequently, the economic and environmental benefits make CM a promising adsorbent in wastewater treatment.

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Properties of coal gangue-Portland cement mixture with carbonation

Cited by 148 publications

References 50 publications

Effect of Nanosilica on Impermeability of Cement‐Fly Ash System

Effect of Nanosilica on Impermeability of Cement‐Fly Ash System

Impact of titanate coupling agent on properties of high density polyethylene composite filled with coal gangue

Novel design of microsphere adsorbent for efficient heavy metals adsorption

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