title: Decomposition of potent greenhouse gas sulfur hexafluoride (SF6) by Kirschsteinite-dominant stainless steel slag.
abstract: 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·FeO·SiO2(CFS)/MgO·FeO·MnO(RO) phase conglomeration. The SF6 decomposition reaction with SSS at 500-700 °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 °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.
authors: School of Environmental and Chemical Engineering, Shanghai University , No. 333 Nanchen Rd., Shanghai 200444, P. R. China.
authors: Jia
authors: J
authors: Zhang
authors: Ji Zhi
authors: JZ
authors: Zhou
authors: Zhi Ping
authors: ZP
authors: Xu
authors: Yajun
authors: Y
authors: Li
authors: Tiehua
authors: T
authors: Cao
authors: Jun
authors: J
authors: Zhao
authors: Xiuxiu
authors: X
authors: Ruan
authors: Qiang
authors: Q
authors: Liu
authors: Guangren
authors: G
authors: Qian
mesh_terms: D000327:Adsorption; D017610:Calcium Compounds / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D017752:Greenhouse Effect / Q000517:prevention & control; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010316:Particle Size; D044367:Phase Transition; D013193:Stainless Steel / Q000737:chemistry*; D013459:Sulfur Hexafluoride / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D017610:Calcium Compounds; D005290:Ferric Compounds; D010087:Oxides; D014867:Water; D013193:Stainless Steel; C016538:lime; D010100:Oxygen; D013459:Sulfur Hexafluoride