Preliminary results on chemical and phase-mineral composition of Syrian petroleum coke and ash

Two composite petroleum coke (PC) samples from a Syrian Refinery, as well as their ashes (PCA) produced at 8000C were studied preliminary for their chemical and phase-mineral composition. The thermal behaviour of PC and PCA based on differential-thermal and thermo-gravimetric analyses was also investigated. The data show that major elements (>1%) in PCA are V, Ca, Si, S, Ni, Fe, Al and Na; minor elements (0.1-1%) include Mo, Mg, Ti, K, P and Zn; while the other 11 elements (As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Pb, Sb, Sn) studied are trace elements (<0.1%). The major minerals and phases identified by powder XRD in PCA are glass, anhydrite and Ni-vanadate; minor minerals include quartz, cristobalite, K feldspar and jarosite; whereas accessory minerals probably are hematite, kaolinite, V oxides and Ni oxide (Ni2O3). It was found that elements such as Ni, V, Mo and S have contents several orders of magnitude greater than the Clarke values for coal ashes, and they would be of great industrial interest for recovery from PCA. On the other hand, a number of toxic and potentially toxic elements (V, Ni, Mo, Cd, Co, Cr, Pb, Zn) have high concentrations in PCA and they could potentially contaminate soils, waters and air during the storage, transport, processing and/or utilization of this product. It was also emphasized that an elucidation of the modes of element occurrence (minerals and phases) in PC and PCA is required in respect to their utilization as energy resource or in order to perform some element extractions. (authors)