应用低钛高炉渣的半钢炼钢:脱磷热力学与工业试验

Applying Low Titanium Blast Furnace Slag to Semi-steel Steelmaking:Dephosphorization Thermodynamics and Industrial Experiment

基于低钛高炉渣资源化综合利用和提高转炉半钢炼钢脱磷效果的考虑,对低钛高炉渣进行喷吹CO_2法脱硫处理后,配入25%~30%的氧化铁皮制备成半钢化渣球用于半钢炼钢。采用建立半钢渣系的脱磷热力学模型和工业试验的方法,对此半钢化渣球冶炼半钢的脱磷能力和冶金效果进行研究。研究结果表明:随着炉渣中TiO_2和Al_2O_3含量的升高,炉渣的脱磷能力降低,特别是当炉渣碱度和温度较低时,脱磷能力降低更快;在两种氧化物含量相同的情况下,TiO_2比Al_2O_3的负面影响更大;随炉渣碱度的增加,炉渣的磷分配比和磷容量均呈先升高后持平的趋势;随渣中w(FeO)的增加,炉渣的磷分配比和磷容量均先升高后降低;随w(MgO)的降低,炉渣的磷分配比和磷容量逐渐降低。采用半钢化渣球冶炼半钢,渣中w(TiO_2+Al_2O_3)和w(FeO)升高,炉渣碱度和w(MgO)降低,控制炉渣碱度在4.0左右,炉渣不仅具有较高的磷分配比和磷容量,并且可以弱化(TiO_2+Al_2O_3)对脱磷能力的影响,确定其加入比例为总渣量的15.0%~20.0%。留渣+化渣球法冶炼半钢的前期平均脱磷率增至58.59%,为原冶炼工艺的1.57倍,吨钢石灰消耗和终点钢水[O]含量分别下降3.48kg/t和112×10-6。

In order to comprehensively utilize low-titanium slag and improve the dephosphorization rate of semi-steel steelma-king,the semi-steel slag ball made of low-titanium slag with injecting CO 2 desulfurization treatment and 25%-30%of the oxide scale was used for semi-steel melting.The dephosphorization thermodynamic model of semi-steel slag system and the method of industrial test were established and conducted to study the dephosphorization and metallurgical impact of semi-steel slag ball.The results indicated that the dephosphorizing capacity would be reduced with increasing w(TiO 2)and w(Al 2O 3),especially under the low temperature and low alkalinity conditions.Compared with Al 2O 3,the TiO 2 can reduce the dephosphorization of slag more.The lg L p and lg C p increased first and then almost invariant with increasing alkalinity,increased first and then decreased as w(FeO)increase,and decreased with the w(MgO)increase.When the semi-tempered slag ball was used in semi-steel steelmaking,the w(TiO 2+Al 2O 3)and w(FeO)of slag increased and the basicity and MgO decreased.The optimum condition for semi-steel smelting is that the basicity of slag is about 4.0 and the proportion of semi-tempered slag ball is 15.0%-20.0%of total slag,and this will result in relatively high lg L p and lg C p of slag,as well as relatively low adverse influence of w(TiO 2+Al 2O 3)on lg L p and lg C p.The early stage dephosphorization rate can be increased to 58.59%,which is 1.57 times of that of the original smelting process.Besides,the per ton lime consumption and the[O]in final steel decrease by 3.48 kg·t-1 and 112×10-6,respectively.