Production of reactive magnesia from desalination reject brine and its use as a binder

Ruan, Shaoqin; Yang, En-Hua; Unluer, Cise

doi:10.1016/j.jcou.2020.101383

Cited by 60 publications

(15 citation statements)

References 77 publications

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“…Therefore, the aforementioned carbonation curing condition is another important factor that determines the fresh and hardened properties of CCP‐OPC paste 28 . Meanwhile, according to previous studies, the carbonation degree of hydrated cement paste is largely dependent on several parameters including the carbonation curing time, gas pressure, water‐to‐cement ratio (W/C) and curing temperature 29,30 . These studies concentrated more on the microstructures and mineral assemblages inside the paste, mortar or concrete of CCP‐OPC composites.…”

Section: Introductionmentioning

confidence: 99%

“…28 Meanwhile, according to previous studies, the carbonation degree of hydrated cement paste is largely dependent on several parameters including the carbonation curing time, gas pressure, water-to-cement ratio (W/C) and curing temperature. 29,30 These studies concentrated more on the microstructures and mineral assemblages inside the paste, mortar or concrete of CCP-OPC composites. However, the mechanical properties, especially the workability of CCP-OPC composites, were often neglected.…”

Section: Introductionmentioning

confidence: 99%

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Influences of CO₂‐cured cement powders on hydration of cement paste

et al. 2022

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Carbonated cement pastes (CCP) can be used as stable carbon storage. In this work, CCP were systematically investigated as supplementary cementitious materials (SCMs)-like components used in ordinary Portland cement (OPC) paste. The fully hydrated cement pastes were pulverized into powders and then exposed to different CO 2 pressure conditions (i.e., 1.0, 2.0 and 2.5 MPa) for 24 h. These CCP powders were then mixed with OPC to form a new binder. Various fresh, hardened and microstructural properties of CCP powders and the mixtures were investigated. Initial results show that the CO 2 sequestration level of CCP increased with the growth of CO 2 pressure, and albeit a pozzolanic reaction occurred inside the mixture, the relatively higher water demand due to the use of 30% replacement of CCP led to the inferior workability and compressive strength than the control group. Finally, a conceptual model relating to the CCP-OPC paste was proposed, facilitating the comprehension of the hydration behaviours of CCP-OPC paste.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influences of CO₂‐cured cement powders on hydration of cement paste

et al. 2022

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“…Compared with the 5-phase crystal content of ordinary composites, the 5-phase crystallization of the BSNSC increased significantly, while the Mg(OH) 2 weak phase decreased. As shown in eq , Mg(OH) 2 reacted with CO 2 in the air to form MgCO 3 . This was due to how 5-phase crystals can grow stably and be adsorbed between MC and VAE (Figure d), promoting the hydration of MgO and facilitating the formation of 5-phase crystals.…”

Section: Resultsmentioning

confidence: 93%

“…As shown in eq 1, Mg(OH) 2 reacted with CO 2 in the air to form MgCO 3 . 28 This was due to how 5-phase crystals can grow stably and be adsorbed between MC and VAE (Figure 2d), promoting the hydration of MgO and facilitating the formation of 5-phase crystals. However, if too much VAE is added, the VAE will condense between the 5-phase crystal structure, which will affect the growth and arrangement of the 5-phase crystal and is not conducive to the formation of the biomimetic swallow nest structure.…”

Section: Resultsmentioning

confidence: 99%

Biomimetic Swallow Nest Structure: A Lightweight and High-Strength Thermal Insulation Material

Zheng

Zuo

2022

ACS Nano

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A common method for reducing carbon emissions and the load-bearing pressure of buildings, and while also achieving improved energy conservation is to prepare porous magnesium-based lightweight composites to reduce waste and environmental hazards. However, due to internal stress, the pores of traditional lightweight composites crack easily and collapse, resulting in composites that are brittle with poor water resistance. These materials cannot achieve both low density and high strength, which limits their application in advanced functional materials. Thus, learned from nature, inspired by swallow’s nest, a solution has been proposed, which is a simple and fast chemical arrangement and assembly method. Using bamboo scraps as the supporting framework and methylcellulose (MC) molecular chains as the templates, 5-phase crystals are grown and arranged on the MC. These crystals are arranged on the bamboo scraps by chemical means with MC acting as a bridge. At the same time, using the high viscosity and flexibility of the vinyl acetate/ethylene (VAE) copolymer emulsion and the formation of magnesium acetate chelate from VAE and hydration products, crystals and bamboo scraps can be assembled. Through these organic–inorganic copolymers, an intercalated and integrated biomimetic swallow nest structure is formed. The biomimetic swallow nest structure composites (BSNSC) imitated the formation process of a natural swallow nest. It is a lightweight material with a thick wall, low connectivity rate, and regular shape. Its density is 0.42 g/cm3, which is still in the density class of ultralight inorganic foam materials, and its compressive strength reaches 6.5 MPa, three times that of ordinary composites. The structure has a strength-to-weight ratio 3.5 times that of ordinary composites and a thermal conductivity much lower than of other thermal insulation materials. In the future, this type of lightweight composites with high strength, high heat insulation, and low density not only functions as a good energy-saving material for buildings but also a good thermal insulation material in the aerospace field.

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“…First, Mg(OH)2 can be converted to reactive MgO and utilized as cement similar to magnesite-derived MgO. (28,29) This process requires lower calcination temperatures (500 -1000°C) (28,30) than Portland cement and doesn't involve direct CO2 emissions from the source material. This high temperature calcination step may be avoided by exposing compacted Mg(OH)2 powder to CO2 under elevated pressure.…”

Section: Introductionmentioning

confidence: 99%

Carbon-Negative Cement Manufacturing from Seawater-Derived Magnesium Feedstocks

Badjatya

Akca

Alvarez

et al. 2021

Preprint

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This study describes and demonstrates a carbon-negative process for manufacturing cement from widely abundant seawater-derived magnesium (Mg) feedstocks. In contrast to conventional Portland cement, which starts with carbon-containing limestone as the source material, the proposed process uses membrane-free electrolyzers to facilitate the conversion of carbon-free magnesium ions (Mg2+) in seawater into magnesium hydroxide (Mg(OH)2) precursors for the production of Mg-based cement. After a low-temperature carbonation curing step converts Mg(OH)2 into magnesium carbonates through reaction with carbon dioxide (CO2), the resulting Mg-based binders can exhibit compressive strength comparable to that achieved by Portland cement after curing for only two days. Although the proposed “cement-from-seawater” process requires similar energy use per ton of cement as existing processes, its potential to achieve a carbon-negative footprint makes it highly attractive to decarbonize one of the most carbon intensive industries.

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Production of reactive magnesia from desalination reject brine and its use as a binder

Cited by 60 publications

References 77 publications

Influences of CO₂‐cured cement powders on hydration of cement paste

Influences of CO₂‐cured cement powders on hydration of cement paste

Biomimetic Swallow Nest Structure: A Lightweight and High-Strength Thermal Insulation Material

Carbon-Negative Cement Manufacturing from Seawater-Derived Magnesium Feedstocks

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Production of reactive magnesia from desalination reject brine and its use as a binder

Cited by 60 publications

References 77 publications

Influences of CO2‐cured cement powders on hydration of cement paste

Influences of CO2‐cured cement powders on hydration of cement paste

Biomimetic Swallow Nest Structure: A Lightweight and High-Strength Thermal Insulation Material

Carbon-Negative Cement Manufacturing from Seawater-Derived Magnesium Feedstocks

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Product

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Influences of CO₂‐cured cement powders on hydration of cement paste

Influences of CO₂‐cured cement powders on hydration of cement paste