Activation of serpentine for CO2 mineralization by flux extraction of soluble magnesium salts using ammonium sulfate
Activation of serpentine for CO2 mineralization by flux extraction of soluble magnesium salts using ammonium sulfate
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DOI：
10.1039/c2ra01347a
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发表时间：
2012-01-01
期刊：
影响因子：
3.9
通讯作者：
Zevenhoven, Ron
中科院分区：
文献类型：
--
作者：
Highfield, James;Lim, HuiQi;Zevenhoven, Ron
本文关注的是廉价和潜在的可回收铵盐在CO2矿化中的作用。利用强大的TG-FTIR联用技术，沿着XRD和ICP-AES，研究了芬兰蛇纹岩在300 ℃以上与熔融硫酸铵接触时镁离子的萃取效率。从微观和克级测试，通量提取泻盐[MgSO 4中心点7 H（2）O]的收益通过中间的Tutton盐，NH 4/Mg双硫酸盐越来越丰富的镁。萃取是通过酸性衍生物，主要是硫酸氢铵和氨基磺酸的作用来实现的，它们是由硫酸铵原位依次产生的。然而，氨基磺酸在400 ℃时以显著的速率挥发和/或分解。这种损失机制主要是造成Mg的适度回收（50-60%）的原因。一种改进的方法将在低于400 ℃的温度下操作，其中镁提取为铁镁矾[（NH 4）（2）Mg-2（SO 4）（3）]是有效的。未来的实验评估使用潮湿的空气，以稳定硫酸氢盐和阻止通量的损失建议。
This paper concerns the growing role of cheap and potentially recyclable ammonium salts in CO2 mineralization. The powerful hyphenated technique TG-FTIR, along with XRD and ICP-AES, were used to shed light on the underlying chemistry and measure the efficiency of magnesium ion extraction from a Finnish serpentinite in contact with molten ammonium sulfate above 300 degrees C. From micro-and gram-scale tests, flux extraction as epsomite [MgSO4 center dot 7H(2)O] proceeds via the intermediacy of Tutton salts, NH4/Mg double sulfates increasingly rich in Mg. Extraction is effected through the agency of acidic derivatives, principally ammonium bisulfate and sulfamic acid, which are created sequentially from ammonium sulfate in situ. However, sulfamic acid volatilizes and/or decomposes at a significant rate by 400 degrees C. This loss mechanism is primarily responsible for the modest recovery of Mg (50-60%). An improved process would operate below 400 degrees C where Mg extraction as efremovite [(NH4)(2)Mg-2(SO4)(3)] is effective. Future experiments evaluating the use of humid air to stabilize the bisulfate and impede the loss of flux are recommended.