TY - JOUR
T1 - Effects of sodium doping on carbonation behavior of α-CS
AU - Zhang, Cheng
AU - Liu, Songhui
AU - Luo, Shuqiong
AU - Chang, Xiangxiang
AU - Shen, Peiliang
AU - Guan, Xuemao
AU - Shi, Caijun
N1 - Funding Information:
The authors appreciate the support from the National Natural Science Foundation of China ( 52108208 , U1905216 , 51808196 ), the National Key R&D Program Intergovernmental International Science and Technology Innovation Cooperation Project ( 2018YFE0107300 ), the fellowship of the China Postdoctoral Science Foundation ( 2020M682290 ), the science and technology project of Henan Province ( 211110231400 , 212102310559 ), the Opening Project of State Key Laboratory of Green Building Materials ( 2021GBM06 ), the Henan Outstanding Foreign Scientists' Workroom ( GZS2021003 ), and the doctor foundation of Henan Polytechnic University ( B2020-11 ).
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/8
Y1 - 2022/8
N2 - In our previous work, a method of stabilizing high-temperature polymorphs (α-CS) by rapid cooling was reported to improve the carbonation activity of ultra-low calcium CO2 sequestration binder (LC-CSB). This paper further investigates the effect of sodium (Na) doping on the properties of α-CS minerals, such as burnability, mineral composition and microstructure. In addition, the carbonation reactivity, carbonation hardening properties, carbonation products and microstructure of α-CS with different sodium doping were also characterized by pH and conductivity, XRD, TGA, FT-IR, SEM-EDS. The mechanism of the effect of sodium doping on the structure and carbonation activity of α-CS minerals was revealed. The results show that the incorporation of sodium significantly improved the burnability of α-CS, lowered the sintering temperature by 180 °C and formed a new phase of Na2O·2CaO·3SiO2(NC2S3). As sodium doping increased, the early carbonation hardening properties were slightly lower than those of pure α-CS, but there was a significant increase in compressive strength and carbonation degree in the later stages. This can be attributed to the fact that sodium doping increases the alkalinity of the paste and delays the dissolution of calcium ions from the α-CS. Furthermore, in the presence of sodium ions, metastable vaterite crystals can be stabilized in addition to calcite. The above results provide potential applications for the low-temperature sintering of alkali-containing solid waste into high carbonation activity LC-CSB.
AB - In our previous work, a method of stabilizing high-temperature polymorphs (α-CS) by rapid cooling was reported to improve the carbonation activity of ultra-low calcium CO2 sequestration binder (LC-CSB). This paper further investigates the effect of sodium (Na) doping on the properties of α-CS minerals, such as burnability, mineral composition and microstructure. In addition, the carbonation reactivity, carbonation hardening properties, carbonation products and microstructure of α-CS with different sodium doping were also characterized by pH and conductivity, XRD, TGA, FT-IR, SEM-EDS. The mechanism of the effect of sodium doping on the structure and carbonation activity of α-CS minerals was revealed. The results show that the incorporation of sodium significantly improved the burnability of α-CS, lowered the sintering temperature by 180 °C and formed a new phase of Na2O·2CaO·3SiO2(NC2S3). As sodium doping increased, the early carbonation hardening properties were slightly lower than those of pure α-CS, but there was a significant increase in compressive strength and carbonation degree in the later stages. This can be attributed to the fact that sodium doping increases the alkalinity of the paste and delays the dissolution of calcium ions from the α-CS. Furthermore, in the presence of sodium ions, metastable vaterite crystals can be stabilized in addition to calcite. The above results provide potential applications for the low-temperature sintering of alkali-containing solid waste into high carbonation activity LC-CSB.
KW - Carbonation
KW - CO sequestration
KW - Sodium doping
KW - Wollastonite
UR - http://www.scopus.com/inward/record.url?scp=85131460235&partnerID=8YFLogxK
U2 - 10.1016/j.cemconcomp.2022.104607
DO - 10.1016/j.cemconcomp.2022.104607
M3 - Journal article
AN - SCOPUS:85131460235
SN - 0958-9465
VL - 131
JO - Cement and Concrete Composites
JF - Cement and Concrete Composites
M1 - 104607
ER -
