垃圾焚烧炉渣铁磁性物质提取及特性表征

Extraction and characterization of ferromagnetic materials from MSWI bottom ash

本研究以重庆市生活垃圾焚烧炉渣为研究对象,分别采用纯水、无水乙醇和丙酮3种溶剂作为提纯介质对焚烧炉渣中铁磁性物质进行湿法提取,并对提取出来的铁磁性物质的铁含量、矿物组分、铁价态分布进行分析表征。实验结果表明,二步-湿法并干法提取所得的铁磁性物质铁含量分别为375.66 g/kg（纯水）、365.79 g/kg（无水乙醇）和344.59 g/kg（丙酮）,是原始炉渣铁含量的4~6倍,是一步-湿法提取所得铁磁性物质铁含量的2~3倍,能够较好地对炉渣铁磁性物质进行富集。二步-湿法并干法提取方式对炉渣中铁的提取效率为63%~73%。XRD分析结果表明,铁磁性物质矿物组分主要包括磁铁矿（Fe3O4）、赤铁矿（Fe2O3）、单质铁（Fe）等含铁矿物组分,以及少量石英（Si O2）和钙铝黄长石（2Ca O·Al2O3·Si O2）等不含铁矿物组分。以纯水、无水乙醇和丙酮作为提纯介质经二步提取所得的铁磁性物质中Fe0∶Fe2＋∶Fe3＋分别为10∶35∶55、12∶43∶：45和9∶33∶59。

Pure water,ethanol and acetone were adopted as extraction solvents for wet magnetic separation of ferromagnetic materials（ FMs） from municipal solid waste incineration（ MSWI） bottom ash. The physicalchemical and mineralogical properties of the extracted FMs were analyzed. The results showed that the Fe% in FMs after two-step separation（ wet separation followed by dry separation） were 375. 66 g / kg（ water）,365. 79 g /kg（ ethanol）,344. 59 g / kg（ acetone）,which were 4—6 times that of the raw bottom ash and 2—2. 5 times that of the one-step（ wet separation） derived FMs. The separation efficiency of the two-step separation reached63% —73% for the three solvents utilized in this study. Mineralogical analysis of the FMs by XRD disclosed that iron-bearing minerals primarily including magnetite（ Fe3O4）,hematite（ Fe2O3）,and metallic iron（ Fe）,as well as a small proportion of non-iron-bearing minerals,like quartz（ Si O2） and gehlenite（ 2Ca O·Al2O3·Si O2）,were the major mineral phases. XPS analysis of the two-step derived FMs disclosed that the Fe0∶ Fe2 ＋∶ Fe3 ＋ratios were 10 ∶ 35 ∶ 55,12 ∶ 43 ∶ 45 and 9 ∶ 33 ∶ 59 for extraction solvents of water,ethanol and acetone,respectively.