Novel procedure of CO2 capture of the CaO sorbent activator on the reaction of one-part alkali-activated slag. Issue 21 (30th March 2021)

• Record Type: Journal Article
• Authors: Zheng, Hao; He, Yan; Zhu, Yuqing; Liu, Leping; Cui, Xuemin
• Is Part Of: RSC advances. Volume 11:Issue 21(2021)
• Page Start: 12476
• Page End: 12483
• Publication Date: 2021-03-30
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra01353j
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The proposed strategy builds a bridge between the alkali-activated cement and CaO-based CO2 sorbents, and this study provides a facile and cost-effective method for controlling the reaction rate of alkali-activated slag. Abstract : CaO derived naturally from limestone or dolomite is an inexpensive and widely available sorbent. Understanding the mechanisms of CaO carbonation at ambient temperature under the assistance of H2 O is important for predicting the reaction of CaO in complex environments and designing novel CaO materials. In this study, we found that the reaction rate of alkali-activated slag is controlled by the CaCO3 layer on a partially carbonized CaO alkali activator. The size of the sorbent increased after the adsorption reaction and the physically adsorbed water in the pores accelerated the carbonation. The carbonation process was governed by CO2 diffusion. When the carbonation conversion rate reached 2–6%, the setting time increased rapidly with the increase in the carbonation rate. This is because the surface of the activator was modified by the thickened CaCO3 product layer, which increased the diffusional resistance and thus prolonged the setting time of the alkali-activated slag.