Study on the Equilibrium of Slag and Hot Metal at Tapping with Respect to Sulfur

Abstract

The blast furnace slag and hot metal are collected from the industrial trials. The collected slag and hot metal samples are re‐melted in a graphite crucible and stirred to investigate the sulfur partition at different stirring times. The experimental oxygen potential is well controlled to simulate the blast furnace conditions. The results show evidently that sulfur is transferred from hot metal to slag, which lead to an increase in the sulfur partition from its initial value (t = 0 min) of 26–33 at 1743 K, and from 23 to 37 at 1773 K after 30 min of slag‐metal reaction. The results strongly indicate non‐equilibrium between slag and hot metal at tapping. The sulfide capacities of the slag with typical composition of the slag at tapping are determined. On the basis of the sulfide capacity data, the theoretical sulfur partition is evaluated. The theoretically calculated partition further supports the finding obtained in the stirring experiments. This finding would suggest the possibility of improvement to increase the usage of blast furnace slag in desulfurization.

Sulfide Capacities in the Al2O3–CaO–MgO–SiO2 System

“…Several studies focused on this quaternary at 1773 K . Figure and present the experimental data at 10 and 15 mass% Al 2 O 3 , respectively.…”

“…The equipment utilized in the experiments is schematically shown in Figure . Only the salient feature of the setup is described, while the details can be found in previous publications . The equipment consisted of an alumina reaction tube, that is, internally connected to a water‐cooled quenching chamber.…”

“…Since its inception, sulfide capacity has been proved to be a useful parameter in optimizing the process of sulfur removal. Extensive studies have been carried out since then to generate data for sulfide capacities of various slags . In view of the extreme importance of the Al 2 O 3 –CaO–MgO–SiO 2 system in both ironmaking and steelmaking, many experimental investigations have been conducted focusing on this system …”

“…The data in the Al 2 O 3 –CaO–MgO–SiO 2 system are due to a number of researchers . The majority of the studies employed gas‐slag equilibration in their experiments while a number of investigation used the copper‐slag equilibration method .…”

Effect of Vanadium and Titanium on Desulfurization of CaO Slag in Liquid Iron

“…In the calculation process, the activities of oxides (sulfides) are based on the mass fraction of the slag [13]. The activity coefficient of an element in liquid iron is calculated by the Wagner model as shown in the following formula [14,15]:…”