Removal of phosphorus from CaO-SiO sub(2)-MgO-Al sub(2)O sub(3)-P sub(2)O sub(5) melts to the gas phase

• Published in: Steel in translation Vol. 44; no. 5; pp. 345 - 349
• Main Authors: Krasnyanskaya, IA, Podgorodetskii, G S
• Format: Journal Article
• Language: English
• Published: 01.05.2014
• Subjects: Basicity; Carbon dioxide; Gas phases; Melts; Oxides; Phosphorus; Silicon dioxide
• ISSN: 0967-0912; 1935-0988
• DOI: 10.3103/S0967091214050076

The behavior of phosphorus in CaO-SiO sub(2)-MgO-Al sub(2)O sub(3)-P sub(2)O sub(5) melts is studied experimentally, so as to determine the potential for the removal of phosphorus from oxide melts to the gas phase. To identify the factors that affect the removal of phosphorus from oxide melts to the gas phase, experiments are conducted with different basicity CaO/SiO sub(2) and with the injection of N sub(2), Ar, and CO + CO sub(2) mixture (with different CO/CO sub(2) ratios). It is established that the basicity is the main factor affecting the transfer of phosphorus from the oxide melt to the gas. When the basicity is 1.0 or less, phosphorus is removed from oxide melts. At higher basicity, no transfer of phosphorus from the oxide melt to the gas is observed. These findings are confirmed by calculations based on the theory of regular ionic solutions for acidic slag, at different basicity values. Calculations show that, when the basicity is 1.05 or less, the activity of SiO sub(2) exceeds that of CaO, and correspondingly SiO sub(2) displaces P sub(2)O sub(5) from its strong compound with CaO. That creates favorable conditions for the transfer of phosphorus from the oxide melt to the gas.