酒钢SPCC钢的LF精炼脱硫

 通过热力学分析，建立了硫分配比与硫容量的关系，用热力学软件FactSage计算渣中Al2O3活度，用KTH模型计算渣的硫容量，对SPCC(一般用冷轧碳素钢薄板坯钢带)两个浇次10炉钢水在LF进站和出站时取钢、渣样以及测氧和温度，通过分析钢样和渣样成分以及生产检测数据，分析了温度、炉渣成分和钢水成分对LF精炼脱硫的影响规律。定义了硫分配比对钢液中溶解氧活度的急剧变化区(a［O］＜4×10-6)，在该区内硫分配比对钢液中溶解氧活度十分敏感，钢液中氧活度的增大导致硫分配比的迅速减小，温度升高，a［O］升高，不仅抵消了升温对脱硫反应轻微的促进作用，反而使硫分配比随温度升高而减小。LF精炼过程Al-O反应未达渣-钢平衡，实际［O］活度介于平衡计算值与Al2O3活度为1的计算值之间，故渣钢硫分配比也介于二者之间。精炼渣二元碱度升高则硫分配比增加，wCaO/wAl2O3在1.6~2.0时脱硫效果较好，硫分配比并不随［Al］s含量的增加而增大，所以用增加w［Al］s来脱硫效果并不明显。钢中夹杂铝(w［Al］t-w［Al］s)降低到10×10-6以下，硫分配比明显升高。

Desulfurization of LF Refining Process for SPCC in JISCO

The relationship between sulfide partition ratio and sulfur capacity was established based on thermodynamic analysis,and the activity of Al2O3 in refining slag was calculated by applying thermodynamic software FactSage and sulfide capacity was estimated by KTH model.Furthermore,ten steel and slag samples were taken at the start and end of ladle furnace(LF) refining for Steel Plate Cold Commercial(SPCC) in Jiuquan Iron and Steel Corporation(JISCO),and at the same time the oxygen activity and temperature were measured using a oxygen probe.The influences of temperature and composition of refining slag and liquid steel on desulfurization at LF for SPCC were analyzed by both experimental data and thermodynamic calculated results.A rapid change region for sulfur partition ratio to dissolved oxygen activity was defined(aO]<4×10-6) and in this region the sulfur partition ratio was sensitive to the aO],i.e.decrease of aO] even a little could result in seriously increase of sulfur partition ratio.Moreover,the value of Al2O3 activity was a key factor to determine aO] in liquid steel while the increase of s could not necessarily reduce it.In addition,the Al-O reaction in LF do not reach slag-steel equilibrium and the actual dissolved O located between the equilibrium value and calculating value taking Al2O3 activity as 1,thus the actual sulfur partition ratio was between them too.Besides,with increase of the temperature,the sulfur partition ratio decreased due to increase of oxygen.The sulfur partition ratio rose with increase of binary basicity and reached its maximum when wCaO/wAl2O3 was between 1.6-2.0.When(wt-ws) was lower than 10×10-6,the sulfur partition ratio would increase a lot.