2019 Pittsburgh AISTech

Calcium Aluminate Formation: Learning a Possible Mechanism Through Size Distributions (Room 410)

06 May 19
9:30 AM - 10:00 AM

Tracks: Ladle & Secondary Refining/Metallurgy - Steelmaking & Casting

Speaker(s): P. Chris Pistorius, POSCO Professor of Materials Science & Eng., Carnegie Mellon University; Mauro Ferreira, Carnegie Mellon University

Industrial and laboratory samples have shown that the calcium aluminates that form immediately after calcium treatment are much smaller than the alumina or spinel inclusions that are present immediately before calcium addition. Experimental results and simulations show that this observation is consistent with a recently proposed reaction mechanism: small calcium sulfide or calcium oxide inclusions form immediately after calcium treatment. The resulting lower activity of dissolved oxygen destabilizes alumina (or spinel), causing Al and Mg to dissolve into the steel; at the Ca-rich inclusions the dissolved elements Al, Mg and O re-precipitate, forming the calcium aluminates.