MoO₃ Evaporation Studies from Binary Systems towards Choice of Mo Precursors in EAF

Abstract

Abstract The evaporation rate of molybdenum oxide from mixtures with CaO or MgO was studied in the temperature range 300‐1573 K. The investigations were carried out using high temperature X‐ray diffraction and thermogravimetry. Further, additions of these precursors to molten steel in the laboratory scale and the Mo yield achieved were determined. The X‐ray studies show that the calcium molybdate is formed from the oxide mixture in the temperature interval 773‐873 K, which precedes the beginning of evaporation of MoO 3 . Results of thermogravimetric studies with mixtures CaO and MgO with MoO 3 as well as the compounds CaMoO 4 and MgMoO 4 confirm the above results. Addition of various molybdenum precursors, viz. the mixtures of carbon with pure MoO 3 , CaMoO 4 and MgMoO 4 , as well as oxide mixtures (CaO + MoO 3 , MgO + MoO 3 ) show that the highest yield was observed for CaMoO 4 + C and MoO 3 + C mixtures, while MgO + C + MoO 3 mixture showed much lower yield.