The research presented in this publication focuses on the removal of phosphorus from basic oxygen furnace slags via the gas phase during carbo-thermal reduction in a bed of inductively heated graphite pieces. Its purpose is to evaluate the effect of the application of a novel reactor concept on the possibilities of phosphorus gasification. The slags are processed in two steps during the experimental trial: First, a silica source is added to reduce the basicity of the slag. In a second step, the actual reduction process is conducted at reaction temperatures of 1,623 K, 1,773 K and 1,923 K, respectively. The molten slag forms a film moving down the reactor with minimal contact time between iron (l) and phosphorus (g) so that a high amount of phosphorus gas can be removed from the reactor. The most important results are that more than 95% of the phosphorus contained in the slags could be reduced, roughly 85% of which were removed via the gas phase. Virtually iron-, chromium- and phosphorus-free slags are obtained. It is concluded that the application of the presented reactor concept based on thermodynamic evaluations potentially tackles the challenges posed by the reaction behaviour of phosphorus.

Graphical Abstract

Phosphorus Gasification during the Reduction of basic Oxygen Furnace Slags in a Novel Reactor Concept