Synthesis of Highly Efficient CaO-Based, Self-Stabilizing CO2 Sorbents via Structure-Reforming of Steel Slag

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• 作者：Sicong Tian ; Jianguo Jiang ; Feng Yan ; Kaimin Li ; Xuejing Chen
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：June 16, 2015
• 年：2015
• 卷：49
• 期：12
• 页码：7464-7472
• 全文大小：427K
• ISSN：1520-5851

文摘

Capturing anthropogenic CO₂ in a cost-effective and highly efficient manner is one of the most challenging issues faced by scientists today. Herein, we report a novel structure-reforming approach to convert steel slag, a cheap, abundant, and nontoxic calcium-rich industrial waste, as the only feedstock into superior CaO-based, self-stabilizing CO₂ sorbents. The CO₂ capture capacity of all the steel slag-derived sorbents was improved more than 10-fold compared to the raw slag, with the maximum uptake of CO₂ achieving at 0.50 g_CO2 g_sorbent^鈥?. Additionally, the initial steel slag-derived sorbent could retain 0.25 g_CO2 g_sorbent^鈥?, that is, a decay rate of only 12% over 30 carbonation鈥揷alcination cycles, the excellent self-stabilizing property allowed it to significantly outperform conventional CaO, and match with most of the existing synthetic CaO-based sorbents. A synergistic effect that facilitated CO₂ capture by CaO-based sorbents was clearly recognized when Mg and Al, the most common elements in steel slag, coexisted with CaO in the forms of MgO and Al₂O₃, respectively. During the calcium looping process, MgO served as a well spacer to increase the porosity of sorbents together with Al₂O₃ serving as a durable stabilizer to coresist the sintering of CaCO₃ grains at high temperatures.