转炉吹炼不同阶段炉渣黏流特性变化

Variation of slag viscous flow characteristics at different blowing stages in converter

为明确转炉吹炼不同阶段炉渣黏流特性变化机理,结合不同时期典型的转炉炉渣成分,利用FactSage热力学模拟软件研究了碱度、FeO、MgO、MnO和Al_(2)O_(3)的变化对CaO-SiO_(2)-FeO-MgO-MnO-Al_(2)O_(3)系转炉渣黏度的影响,并结合生产实际给出了转炉冶炼不同阶段适宜的炉渣碱度、炉渣中合理的FeO、MgO、MnO及Al_(2)O_(3)含量。研究结果表明,不同碱度条件下转炉渣黏度随温度升高而逐渐减小,不同温度条件下转炉渣黏度随碱度增大呈现先增大后减小的趋势。炉渣黏度受FeO、MgO和Al_(2)O_(3)含量变化影响较大,受MnO含量变化影响相对较小。炉渣流动性主要与炉渣结构的聚合度和渣中固相质量分数有关,FeO、MgO和Al_(2)O_(3)含量增加可以破坏渣中硅酸盐聚合体的网络结构,多余MgO易导致渣中高熔点固相析出;Al_(2)O_(3)含量较低时,在渣中以复杂的四面体结构AlO45-形式存在,易形成铝酸钙等高熔点物质,从而改变炉渣流动性。结合实际生产综合考虑,在转炉冶炼前期,炉渣碱度控制为1.4~1.5,FeO质量分数控制为20%左右,MgO质量分数控制为6%~8%,MnO质量分数控制为6%以上,Al_(2)O_(3)质量分数控制为3%~5%,炉渣黏度较为适宜,炉渣流动性较好;在转炉冶炼中后期,炉渣碱度控制为3.0~3.5,FeO质量分数控制为15%~20%,MgO质量分数控制为6%~8%,MnO质量分数控制为3%~6%,Al_(2)O_(3)质量分数控制为3%以下,炉渣具有良好的流动性。

To clarify the variation mechanism of furnace slag viscous flow characteristics in different stages of converter blowing.According to typical converter slag compositions during different stages,the effects of basicity,FeO,MgO,MnO and Al_(2)O_(3)on the viscosity of CaO-SiO_(2)-FeO-MgO-MnO-Al_(2)O_(3)converter slag was studied by using Factsage thermodynamic simulation software.The suitable basicity of converter slag,reasonable FeO,MgO,MnO and Al_(2)O_(3)contents in converter slag during different stages were given in combination with production practice.The results showed that the viscosity of converter slag decreased gradually with the increase of temperature under different alkalinity conditions,and the viscosity of converter slag increased first and then decreased with the increase of alkalinity under different temperature conditions.The viscosity of furnace slag is greatly affected by the content of FeO,MgO and Al_(2)O_(3),while the content of MnO had relatively little effect on the viscosity of furnace slag.The fluidity of furnace slag is mainly related to the polymerization degree of furnace slag structure and the mass fraction of solid phase in furnace slag.The increase of FeO,MgO and Al_(2)O_(3)content could destroy the network structure of silicate polymer in slag,and excess MgO could easily lead to the precipitation of high melting point solid phase in slag.When the content of Al_(2)O_(3)is low,it exists in furnace slag in the form of complex tetrahedral structure AlO5-4,which is easy to form high melting point substances such as calcium aluminate,thus changing the fluidity of furnace slag.The actual production considered that in the early stage of converter smelting,the basicity of slag is controlled at about 1.4-1.5,the content of FeO,MgO,MnO and Al_(2)O_(3)was controlled at about 20%,about 6%-8%,above 6%and about 3%-5%,respectively.The viscosity of slag is suitable and the fluidity of slag was well.In the middle and later stages of converter smelting,the basicity of slag should be controlled at about 3.0-3.5,the content of FeO,MgO,MnO and Al_(2)O_(3)should be controlled about 15%-20%,about 6%-8%,about 3%-6%and below 3%,respectively.The furnace slag has well fluidity.