An experimental study of dephosphorization in the hydrogen plasma smelting reduction process

Abstract

Lately, the interest in CO2 emission–free steelmaking has been increasing. Especially hydrogen is seen as a potential reducing agent in steelmaking, as the hydrogen–based reduction is a CO2 –free alternative to conventional steelmaking processes. One of the potential alternatives is hydrogen plasma smelting reduction. The aim of this thesis is to study dephosphorization and to find about what kind of effect does different slag FeO content have on dephosphorization.

In the first part of the thesis, HPSR process and its fundamentals are studied. The main emphasis is in the dephosphorization phenomena in steelmaking. The effect of slag composition on the dephosphorization rate and efficiency is of great interest.

In the second part of the thesis, the effect of slag composition, especially the effect of FeO content was studied by making use of literature data and with laboratory–scale high temperature slag–metal experiments. The experiments were carried out in conditions that were assumed to resemble the conditions in the HPSR after the reduction stage. The results indicate that the dephosphorization rate and efficiency increase when increasing the FeO content in the initial slag. However, the available crucible material was not optimal for the experiments, and thus further studies are needed to confirm these findings.