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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。
Through the thermodynamic analysis, the relationship between the sulfur distribution ratio and the sulfur capacity was established. The activity of Al2O3 in the slag was calculated by the thermodynamic software FactSage. The sulfur capacity of the slag was calculated by KTH model. For the SPCC (generally used cold-rolled carbon steel thin slab strip) Two pouring furnace 10 molten steel in LF into and out of the station to take steel, slag samples and oxygen and temperature, by analyzing the steel samples and slag samples and production testing data analysis of the temperature, slag composition and composition of molten steel LF The influence of refining desulfurization. Define the sulfur distribution ratio of molten steel in the rapid changes in the activity of oxygen (a [O] <4 × 10-6), in the region of sulfur distribution ratio of molten steel is very sensitive to the activity of dissolved oxygen, molten steel The increase of oxygen activity led to the rapid decrease of sulfur distribution ratio. The increase of a [O] not only counteracted the slight effect of temperature increase on desulfurization, but decreased the sulfur distribution ratio with the increase of temperature small. In the LF refining process, the Al-O reaction did not reach the slag-steel balance, and the actual [O] activity was between the calculated value of the equilibrium and the calculated value of the Al2O3 activity. Therefore, the sulfur distribution ratio of the slag was also in between . When the binary basicity of refined slag increased, the sulfur distribution ratio increased. When wCaO / wAl2O3 was between 1.6 and 2.0, the desulfurization effect was better and the sulfur distribution ratio did not increase with the increase of [Al] s content. Therefore, s to desulfurization effect is not obvious. The inclusions in steel (w [Al] t-w [Al] s) decreased to less than 10 × 10-6, and the sulfur distribution ratio increased obviously.