Regular Article

Reducing dephosphorization of silicomanganese ferroalloys by CaO-based slag

¹ State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China
² State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, PR China
³ School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China

^* e-mail: ghzhang_ustb@163.com

Received: 27 November 2016
Received in final form: 19 January 2017
Accepted: 7 March 2017

Abstract

The reducing dephosphorization of silicomanganese ferroalloys by CaO-based slags is investigated in the present paper. Experiments are carried out in an induction furnace in air atmosphere to simulate the practical production condition. It is found that dephosphorization took place very quickly by using CaO-CaF₂ slag. In addition, decarburization and desulfurization also happened with the dephosphorization process. There is almost no dephosphorization when the silicon content in silicomanganese ferroalloy melt is less than 10 wt.%, while the dephosphorization ratio increases significantly as the silicon content is larger than 10 wt.%. When CaF₂ in the slag is partly replaced by Al₂O₃, the dephosphorization ratio decreases sharply, and there is almost no dephosphorization for CaO-Al₂O₃ slag even when silicon content in the ferroalloy melt is 22 wt.%.