Fe_2O_3粉加入量对镁钙质中间包干式料性能的影响

Effects of Fe_2O_3 powder additions on properties of magnesia-calcia dry materials for tundish

以w(CaO)≈20%的镁钙砂(其粒度为5～3、3～1、1～0.2、≤0.2和≤0.074 mm)为主原料制成镁钙质中间包干式料,并研究了加入不同量Fe2O3粉(其质量分数分别为0、1%、2%、3%、4%)对干式料性能的影响。结果表明:1)加入Fe2O3粉可以增加镁钙质干式料的低温和中温强度,但加入质量分数超过3%后,干式料的低温强度明显下降,高温烧后显气孔率上升,体积密度下降,体积膨胀加剧;综合分析认为,镁钙质干式料中Fe2O3粉的加入质量分数在2%～3%较适当。2)加入Fe2O3粉的镁钙质干式料抗熔渣侵蚀性能较好,这是由于加入的Fe2O3与镁钙砂中的CaO反应生成了低熔点矿物铁酸二钙,促进了材料的烧结,从而提高了其抗熔渣侵蚀性。

Effects of microsilica additions（0,1%,1.5%,2% and 2.5% in mass） on properties of Al2O3-SiC-C castables for iron trough were researched using bauxite（8-5 mm）,brown corundum（8-5,5-3 and 3-1 mm）,SiC（≤1 and ≤0.044 mm） and dense corundum（≤1 and ≤0.044 mm） as main starting materials,and maintaining the total addition of microsilica and white clay at 2.5 mass%.The results indicate that：（1）after firing at 1 100 and 1 500 ℃ for 3 h,respectively,with microsilica addition increasing,that is,with white clay addition decreasing,the permanent change in dimensions on heating decreases gradually,the apparent porosity,cold modulus of rupture,and hot modulus of rupture（1 450 ℃ 0.5 h） firstly increase and then decrease,and the bulk density shows an opposite trend with apparent porosity;（2）after thermal shock,it performs the maximum residual strength with 1.5% of microsilica addition,and the lowest residual strength with 2% of microsilica addition;（3）the slag resistance is the best when the microsilica addition is 2%.Based on an overall consideration,the Al2O3-SiC-C rapid dry castables with 2% of microsilica and 0.5% of white clay have the optimum properties.The produced castables were used for the 750 m3 single taphole trough of Laiwu I ＆ S（Group） Co.,Ltd.and the main trough tapped 140 thousand tons hot metal without maintenance.