Application of Capillarity of Solid CaO to Dephosphorization of Hot Metals

Abstract

The penetration behavior of molten slag in solid CaO has been observed when liquid iron alloy containing phosphorus was oxidized by air or oxygen in CaO crucible. It was found from the present experiment that the phosphate was absorbed in the porosities of solid CaO accompanying the penetration of molten FeO slag when the carbon-saturated liquid iron alloy was oxidized at localized position. The phosphate is found to be fixed as 4CaOP₂O₅ from X-ray diffraction. Since the penetration can be evaluated theoretically to proceed much faster than the penetration rate obtained from the experimental results, the oxidation process of liquid iron alloy is considered to be the rate-determining step for the total reaction rate of the dephosphorization process using the capillarity of solid CaO. The application of the capillary phenomena to the dephosphorization of hot metal by solid CaO may be one of the useful engineering processes although the adequate oxidation procedures have to be considered.