碳酸钙在转炉粗炼钢中的脱磷行为

Dephosphorization behavior of BOF crude steel using calcium carbonate

钢铁企业通过实践发现,在转炉出钢过程中向钢液添加CaCO_(3)可以有效降低钢中磷含量。为了解此过程中脱磷机制,采用CaCO_(3)、MgCO_(3)和CO_(2)等试剂对转炉粗炼钢进行了模拟脱磷实验,并结合热力学计算,揭示了CaCO_(3)的脱磷机制。结果表明,上述3种试剂都具有脱磷作用,其中CaCO_(3)的脱磷效果最好。MgCO_(3)分解产生的MgO不具备脱磷作用,其主要依靠分解产生的CO_(2)进行脱磷。CO_(2)与钢液反应的实验结果进一步证明了CO_(2)具有脱磷能力。CaCO_(3)脱磷是其分解产物CaO和CO_(2)共同作用的结果。CaO会与钢液中的磷结合生成富磷相(CaO-P2O5-FeOx)存在于渣中;CO_(2)在搅拌钢液的同时还会氧化钢液中的磷,其脱磷产物为气态P2O5。

The industrial practice of a steel company shows that adding Ca CO_(3) to BOF steel during tapping can effectively reduce the phosphorus content in steel.In order to understand the dephosphorization mechanism in this process,Ca CO_(3),Mg CO_(3),CO_(2) and other agents were used to remove phosphorus from BOF crude steel.Combined with thermodynamic calculations,the dephosphorization mechanism using Ca CO_(3) was revealed.The results indicate that all the reagents mentioned above have dephosphorization effects,with Ca CO_(3) having the best dephosphorization effect.The Mg O produced by the decomposition of Mg CO_(3) does not have dephosphorization effect,and it mainly relies on the CO_(2) generated by the decomposition for dephosphorization.The experimental results of the reaction between CO_(2) and molten steel further demonstrate that CO_(2) has the ability to remove phosphorus.The dephosphorization of Ca CO_(3) is the result of the combined action of its decomposition products Ca Oand CO_(2).Ca O will combine with phosphorus in the molten steel to form a phosphorus rich phase(Ca O-P2O5-Fe Ox)that exists in the slag;CO_(2) also oxidizes phosphorus in the molten steel while stirring,and its dephosphorization product is gaseous P2O5.