Steel prodn. in refractory lined converter - by blowing oxygen onto charge of liq. metal and liq. slag comprising lime and recirculated granulated steel slag

摘要

Steel is made in a steel converter lined with refractory brick, whereby oxygen is blown from above onto the charge of liq. metal and liq. slag in the converter. The slag used is free from fluorspar and is comprised of (per ton of finished steel) 40-47 kg lime and 15-25 kg recirculated granulated steel slag. In a pref. process, the crude liq. iron fed to the converter has a Mn content of 0.6-0.75 wt.%, esp. about 0.7wt.%; 42-45 kg lime and 16-18 kg steel slag is metered into the liq. metal; the lime is metered in a single lot at the beginning of the oxygen blow; the comminuted steel slag has a particle size of 25-70 mm; and the lime used is dolomitic lime. Process allows prodn. of steel using smaller amts. of lime per ton of finished steel than in prior art processes (e.g. 40-47 kg against 60-70 kg previously). The slag produced is less aggressive than in known processes, so that the refractory brickwork has a longer life and the process is more economical to run.