Decomposition of Potent Greenhouse Gas Sulfur Hexafluoride (SF6) by Kirschsteinite-dominant Stainless Steel Slag

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• 作者：Jia Zhang ; Ji Zhi Zhou ; Zhi Ping Xu ; Yajun Li ; Tiehua Cao ; Jun Zhao ; Xiuxiu Ruan ; Qiang Liu ; Guangren Qian
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：January 7, 2014
• 年：2014
• 卷：48
• 期：1
• 页码：599-606
• 全文大小：476K
• ISSN：1520-5851

文摘

In this investigation, kirschsteinite-dominant stainless steel slag (SSS) has been found to decompose sulfur hexafluoride (SF₆) with the activity higher than pure metal oxides, such as Fe₂O₃ and CaO. SSS is mainly made up of CaO路FeO路SiO₂(CFS)/MgO路FeO路MnO(RO) phase conglomeration. The SF₆ decomposition reaction with SSS at 500鈥?00 掳C generated solid MF₂/MF₃ and gaseous SiF₄, SO₂/SO₃ as well as HF. When 10 wt % of SSS was replaced by Fe₂O₃ or CaO, the SF₆ decomposition amount decreased from 21.0 to 15.2 or 15.0 mg/g at 600 掳C. The advantage of SSS over Fe₂O₃ or CaO in the SF₆ decomposition is related to its own special microstructure and composition. The dispersion of each oxide component in SSS reduces the sintering of freshly formed MF₂/MF₃, which is severe in the case of pure metal oxides and inhibits the continuous reaction of inner components. Moreover, SiO₂ in SSS reacts with SF₆ and evolves as gaseous SiF₄, which leaves SSS with voids and consequently exposes inner oxides for further reactions. In addition, we have found that oxygen significantly inhibited the SF₆ decomposition with SSS while H₂O did not, which could be explained in terms of reaction pathways. This research thus demonstrates that waste material SSS could be potentially an effective removal reagent of greenhouse gas SF₆.