摘要:
The desulfurization ability of refining slag with relative lower basicity (
B) and Al
2O
3 content (
B = 3.5–5.0; 20wt%–25wt% Al
2O
3) was studied. Firstly, the component activities and sulfide capacity (
CS) of the slag were calculated. Then slag-metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution (
LS). Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO-Al
2O
3-SiO
2-MgO system with the basicity of about 3.5–5.0 and the Al
2O
3 content in the range of 20wt%–25wt% has high activity of CaO (
aCaO), with no deterioration of
CS compared with conventional desulfurization slag. The measured
LS between high-strength low-alloyed (HSLA) steel and slag with a basicity of about 3.5 and an Al
2O
3 content of about 20wt% and between HSLA steel and slag with a basicity of about 5.0 and an Al
2O
3 content of about 25wt% is 350 and 275, respectively. The new slag with a basicity of about 3.5–5.0 and an Al
2O
3 content of about 20wt% has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.