title: Characterization of stabilized/solidified refinery oily sludge and incinerated refinery sludge with cement using XRD, SEM and EXAFS.
abstract: Solidification/stabilization (S/S) of refinery oily sludge and incinerated oily sludge (ash) with cement type I42.5 and II42.5 was investigated using, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectroscopy (EDS) and Extended X-ray Absorption Fine Structure (EXAFS). The results showed that delayed ettringite formation (DEF) and major cement hydration reactions occurred. XRD analysis of S/S oily sludge samples revealed cement-bearing solid phases, such as portlandite, calcite, C(3)S, C(2)S and C(4)AF. SEM analysis, confirmed ettringite at solidified oily sludge samples. Solidified ash samples contained ettringite substituted by chromates. However, solid phases found in solidified ash samples with I42.5 cement showed minor variation in type and structure compared to those observed in solidified ash samples with II42.5 cement. Fe K edge EXAFS analysis revealed the presence of iron oxides in both S/S wastes. The comparison between spectra of the S/S resulting materials and the ones of their original components, showed that the first sphere Fe-O distances were longer than in the pure iron oxide thereby providing evidence that the resulting materials were not simple mixtures, but products of a reaction that modified the local environment of iron.
authors.affiliation: Department of Environmental Engineering, Democritus University of Thrace, Xanthi, Greece. akaramal@env.duth.gr
authors.forename: Athanasios K
authors.initials: AK
authors.lastname: Karamalidis
authors.forename: Vasileios
authors.initials: V
authors.lastname: Psycharis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Nicolis
authors.forename: Eleni
authors.initials: E
authors.lastname: Pavlidou
authors.forename: Simone
authors.initials: S
authors.lastname: Benazeth
authors.forename: Evangelos A
authors.initials: EA
authors.lastname: Voudrias
mesh_terms: D003252:Construction Materials; D004784:Environmental Monitoring / Q000379:methods; D017745:Incineration; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D009821:Oils / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D046590:Spectroscopy, Electron Energy-Loss / Q000379:methods*; D018505:Waste Management / Q000379:methods; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D009821:Oils; D012722:Sewage