Development of methodology for surface characterization of vanadium containing slag

• Swedish steel producers are particularly interested in the recovery of vanadium oxide from the steelmaking slag because of its high content in the LD-converter slag. Hence, optimization of the vanadium recovery has strong economic and environmental impact. Solving the problem with vanadium recovery from the slag requires development of reliable technique for assessing the oxidation state of vanadium. This paper summarizes methodology for the robust analysis of the Ca-Si-based slag materials containing vanadium oxide in different oxidation states utilizing XPS. The measurements show that because of high oxygen affinity of vanadium oxides and number of oxidation states, only fracturing of machined specimens in an ultra-high vacuumchamber, connected to XPS, allows accurate evaluation of oxidation state of vanadium in slag. Proper charge compensation, required due to non-conductive nature of the slag specimens, is considered to be the main problem faced during analysis. As neither carbon nor oxygen signals were proven to be appropriate reference point for charge referencing in this material, the calcium 2p peak position at 347.0 eV, characteristic for CaSiO3, shown to be the most stable and reliable binding energy calibration reference and was used during the charge compensation. Results indicated that in the case of the studied slags,vanadium oxides present are formed preferably by mixture of V2O3 and VO2, depending on the reducing potential of the controlled atmosphere applied during the slag synthesis.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

vanadium containing slag

oxide standards

LD-converter slag

stoichiometric vanadium oxides

XPS

charge compensation

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