Preparation of oily sludge-derived glass-ceramics by low-temperature melting with addition of CaF2

Abstract

Oily sludge (OS), a hazardous waste that generated in the process of petroleum exploration, utilized as raw material in this study for preparation of high value-added glass-ceramics. The effect of CaF2 addition and temperature on the melting behavior, crystallization mechanism, physical-chemical properties and heavy metals leaching of glass-ceramics was highlighted. The results indicated that the obtained parent glass demonstrated completely amorphous structure at 1200 °C when CaF2 content was 4 wt%. The addition of CaF2 improved crystallinity of glass-ceramics, which further improved the glass-ceramics properties. Comparing the properties of OC-1200-830 with OCF4-1030, it was observed that the density increased from 2.27 g/cm3 to 2.60 g/cm3, compressive strength increased from 56.43 MPa to 122.00 MPa, bending strength increased from 6.16 MPa to 11.41 MPa, acid resistance increased from 92.8% to 96.8%, alkali resistance increased from 94.6% to 98.2%, and water absorption reduced from 0.19% to 0.12%. The leaching concentrations of heavy metals in the glass-ceramics were below than the thresholds required in GB 5058.3–2007, China. The theoretical energy consumption of glass-ceramics melted at 1200 °C was 30.84%–41.37% lower than that melted at 1500 °C, which demonstrated that the glass-ceramics prepared in this study have cost advantages.