“全三脱”工艺流程中脱碳渣返回脱磷转炉利用

为了在"全三脱"工艺流程中实现炉渣的高效循环利用,将w((P2O5))较低的热态脱碳炉终渣通过渣罐兑入脱磷炉继续发挥脱磷作用。分析结果表明,提高返回渣量及脱磷渣磷分配比均可显著降低脱磷炉石灰消耗量,当渣钢磷分配比及返回渣量控制合适时,脱磷炉可不加入石灰而使半钢磷质量分数达到目标值。对脱碳炉渣在脱磷炉冶炼中的再熔化过程进行计算分析,随着铁水中硅元素的氧化,脱碳渣碱度降低而不断熔化,逐渐发挥脱磷作用。在"全三脱"工艺流程中成功开发了转炉渣热态循环利用工艺,脱磷率提高约6%,返回脱碳渣加入量约为67.13 kg/t,石灰、轻烧白云石和萤石分别节约9.37、1.15和2.45 kg/t,半钢温度提高约7℃。

Recycle of decarburization-slag in dephosphorization-furnace of duplex process in converter

During duplex process in converter,the decarburization-slag with low w((P2O5)) was added into dephosphori-zation-furnace through slag-vessel to realize the recycle of slag. The amount of recycle slagand the phosphorus distribu-tion would greatly affect the addition amount of lime in dephosphorization-furnace,the target phosphorus content could be achieved without adding any lime in dephosphorization-furnace if the recycle slag amount and the phosphorus distri-bution were controlled properly. The dissolution of decarburization-slag in dephosphorization-furnace was calculated and analyzed. As the Si in hot metal was oxidized,the melting point of slag was lowered with the decrease of slag basicity in the blowing process. The recycle slag process was developed in the plant trials,the lime was saved by 9.37 kg/t,the light-burned dolomite was saved by 1.15 kg/t,the fluorite was saved by 2.45 kg/t,and the temperature increased by ap-proximately 7℃ when the recycle slag amount increased to 67.13 kg/t. The dephosphorization rate increased by approx-imately6%.