Hwang Kyung-Yup, Ahn Jun-Young, Kim Cheolyong, Seo Jeong-Yun, Hwang Inseong
School of Civil and Environmental Engineering, Pusan National University, 30 Jangjeon-Dong, Geumjeong-Gu, Busan, 609-735, Korea.
Environ Geochem Health. 2015 Dec;37(6):1063-72. doi: 10.1007/s10653-015-9750-8. Epub 2015 Jul 30.
An MgO-based binder was developed that could stabilize fine dredged sediments for reuse and store CO2. Initially, a binder consisting of fly ash (FA) and blast furnace slag (BFS) was developed by using alkaline activators such as KOH, NaOH, and lime. The FA0.4-BFS0.6 binder (mixed at a FA-to-BFS weight ratio of 4:6) showed the highest compressive strength of 10.7 MPa among FA/BFS binders when 5 M KOH was used. When lime (L) was tested as an alkaline activator, the strength was comparable with those obtained when KOH or NaOH was used. The L0.1-(FA0.4BFS0.6)0.9 binder (10 % lime mixed with the FA/BFS binder) showed the highest strength of 11.0 MPa. Finally, by amending this L0.1-(FA0.4BFS0.6)0.9 binder with MgO, a novel MgO-based binder (MgO0.5-(L0.1-(FA0.4BFS0.6)0.9) 0.5) was developed, which demonstrated the 28th day strength of 11.9 MPa. The MgO-based binder was successfully applied to stabilize a fine sediment to yield a compressive strength of 4.78 MPa in 365 days, which was higher than that obtained by the Portland cement (PC) system (3.22 MPa). Carbon dioxide sequestration was evidenced by three observations: (1) the decrease in pH of the treated sediment from 12.2 to 11.0; (2) the progress of the carbonation front inward the treated sediment; and (3) the presence of magnesium carbonates. The thermogravimetric analysis (TGA) results showed that 67.2 kg of CO2 per ton of the treated sediment could be stored under the atmospheric condition during 1 year.
开发了一种基于氧化镁的粘结剂，它可以稳定疏浚细颗粒沉积物以便再利用，并储存二氧化碳。最初，通过使用氢氧化钾、氢氧化钠和石灰等碱性活化剂，开发了一种由粉煤灰（FA）和高炉矿渣（BFS）组成的粘结剂。当使用5M氢氧化钾时，FA0.4 - BFS0.6粘结剂（按FA与BFS的重量比4:6混合）在FA/BFS粘结剂中表现出最高抗压强度，为10.7MPa。当测试石灰（L）作为碱性活化剂时，其强度与使用氢氧化钾或氢氧化钠时相当。L0.1 - (FA0.4BFS0.6)0.9粘结剂（10%的石灰与FA/BFS粘结剂混合）表现出最高强度，为11.0MPa。最后，通过用氧化镁对这种L0.1 - (FA0.4BFS0.6)0.9粘结剂进行改性，开发出一种新型的基于氧化镁的粘结剂（MgO0.5 - (L0.1 - (FA0.4BFS0.6)0.9) 0.5），其28天强度为11.9MPa。这种基于氧化镁的粘结剂成功应用于稳定细颗粒沉积物，在365天内产生的抗压强度为4.78MPa，高于波特兰水泥（PC）体系（3.22MPa）。通过三个观察结果证明了二氧化碳的封存：（1）处理后沉积物的pH值从12.2降至11.0；（2）碳化前沿向处理后沉积物内部推进；（3）碳酸镁的存在。热重分析（TGA）结果表明，在大气条件下，每吨处理后的沉积物每年可储存67.2kg二氧化碳。
