AOD炉衬MgO-CaO砖的侵蚀机理

采用光学显微镜(OM)、扫描电镜(SEM)和能谱仪(EDAX)对AOD炉用镁钙砖的残砖进行了分析,探讨了炉衬镁钙砖的侵蚀机理。结果表明:AOD炉衬镁钙砖的蚀损主要是由硅酸盐液相的溶解和渗透引起的;在残砖反应带和原砖带之间形成的平行于工作面的横断裂纹,是加速镁钙砖损毁的重要因素。     

AOD炉渣对镁钙质耐火材料的侵蚀机理

采用静态坩埚法将AOD炉渣线区镁钙砖在1 700℃空气气氛下高温热处理3 h后进行抗渣试验。结合XRD、SEM、EDS等测试手段,分析了AOD炉两个阶段炉渣对渣线区镁钙砖的侵蚀机理。结果表明：低碱度的氧化期炉渣对镁钙砖侵蚀明显,炉渣在表面张力和毛细管力作用下,进入镁钙砖内部与CaO反应生成低熔点的铁酸二钙2CaO·Fe₂O₃(C₂F),促进砖中CaO溶解,破坏了原有的致密结构,使反应层结构变得疏松、易剥落;镁钙砖中方镁石晶簇吸收液态渣中的铁、铬、锰氧化物,并在其晶内和晶间形成复合尖晶石结构,从而提高镁钙砖表面渣的黏度,减缓渣的侵蚀;还原期炉渣碱度较高,对镁钙砖的侵蚀作用较弱,主要表现为SiO₂向砖内侵蚀渗透,以及体积效应和温度梯度导致镁钙砖表面小尺寸方镁石晶簇向渣中剥落。     

富含MnO的不锈钢炉渣对MgO-C耐火材料的侵蚀

为了研究高Mn不锈钢生产中MnO对MgO-C砖的蚀损速度的影响,将MgO-C耐火材料试样暴露于不同含量的MnO(高达26%)炉渣中。用过砖的显微结构表明,在耐火材料和炉渣的表面出现了许多富含Mn的金属颗粒而且形成了(Mg,Mn)O的固溶体,但是并没有观察到由于炉渣中MnO含量高从而导致蚀损速度明显加快的现象。关于耐火材料的蚀损问题,炉渣中MgO的含量是主要因素。通过将实验结果和动态计算结合起来,讨论了蚀损过程。     

含TiC熔渣对MgO-C砖的侵蚀机制

为了有效回收钛资源和满足高温碳化—低温氯化工艺对耐火材料的要求,采用热力学计算、XRD和SEM等研究手段分析了高温碳化过程中含TiC熔渣对MgO-C砖的侵蚀机制。热力学计算结果表明：1)温度越高,熔渣的侵蚀能力越强,当温度低于1 560℃时,熔渣与MgO-C砖反应生成MgAl₂O₄、Mg₂SiO₄和MgTi₂O₄等高熔点物相,对MgO-C砖侵蚀较慢,但当温度高于1 560℃时,前期生成的高熔点物相逐渐溶解,从而对MgO-C砖侵蚀加剧;2)随着碳化反应的进行,熔渣中TiO₂含量降低,TiC含量逐渐增加,熔渣对MgO-C砖的侵蚀逐渐减弱。用后MgO-C砖的显微结构分析发现：镁碳砖的侵蚀机制是气氛中氧气与碳反应,形成气孔,熔渣中TiO₂和SiO₂等再与基质MgO反应先形成高温中间相,随着反应进行再形成低熔点相,导致MgO-C砖逐渐被侵蚀。     

MgO-C砖在CaO-SiO_2-Fe_2O_3系渣中的蚀损机理

MgO-C砖广泛用于炼钢炉,本文利用转炉渣对MgO-C砖做了侵蚀试验,并进行了成份分析,查明了MgO-C砖的蚀损状态。     

渣对铝镁炭砖的侵蚀与渗透

对电炉连铸钢包用后铝镁炭砖进行了ＳＥＭ和ＥＰＭＡ观测分析。探讨了渣对铝镁炭砖的侵蚀与渗透机理，并提出了抑制渣渗透的措施。     

LF炉渣线用MgO-C砖的防氧化措施

通过比较不同的防氧化剂对LF炉渣线部位MgO-C砖抗氧化性、高温强度、抗渣性的影响,认为以Al-Mg合金与少量B     

β-Si3N4对MgO-C砖高温性能的影响

研究了β-Si3N4对镁碳砖高温性能的影响及其作用机理.研究表明由于β-Si3 N4呈针状结构,热膨胀系数低,对多数熔渣和金属的润湿性小,加入β-Si3N4的镁碳砖,其高温抗折强度提高,热膨胀率降低,抗渣侵蚀性提高;另外,在反应层与原砖层之间发现有富硅层形成,这有利于抑制石墨和氮化硅的氧化以及渣的渗透.     

精炼钢包渣线镁碳砖被侵蚀的显微分析

通过静态和动态抗渣实验,考查了精炼钢包用渣线镁碳砖被侵蚀的情况,并从显微分析的角度研究了镁碳砖被侵蚀的原因.研究表明,在静态实验中,镁碳砖中的氧化镁会溶解到熔渣中去,方镁石晶粒间的杂质在高温下形成低熔相成为熔渣侵入的通道并促进了该溶解过程.在动态实验中,由于镁碳砖中的石墨会溶解到钢水中,位于钢水和熔渣界面的熔渣进而渗透到镁碳砖中,加上钢水的冲刷等因素造成镁碳砖的损毁.     

Corrosion mechanism of MgO-C bricks used as linings in a vanadium extraction converter

To extend the service life of MgO-C bricks used as linings in vanadium extraction converters, their corrosion mechanism was investigated using stationary immersion and rotary crucible methods at 1673 K. The effects of oxides in vanadium slag were studied using the slag invasion method. The results showed that a decarburization layer was formed but was not effectively sintered under vanadium extraction conditions, resulting in it having a loose structure and poor binding strength. When slag-splashing technology was applied to protect the converter, the decarburization layer and slag-splashing layer easily fell off due to scouring by the molten pool. Consequently, the poor strength of the decarburization layer was the main reason for the poor anti-erosion performance of the MgO-C bricks and the weak effect of slag-splashing technology. In addition, higher contents of SiO₂ and TiO₂ in vanadium slag could form low melting point compounds and increase the thickness of the decarburization layer, thereby accelerating the MgO-C brick corrosion rate. Higher contents of FeO in the vanadium slag not only formed low melting point compounds but also caused a decarburization reaction with the MgO-C bricks. However, with increases of V₂O₃ in the slag, the formation of high melting point compounds decreased the corrosion rate and corrosion depths.     

利用铝铬渣与废弃镁碳砖合成镁铝尖晶石材料

以铁合金厂铝铬渣和钢厂废弃镁碳砖为主要原料,通过固相烧结反应合成MgAl2O4材料,研究分析铝铬渣与废弃镁碳砖细粉比例关系对合成MgAl2O4材料组成和结构的影响.用XRD、SEM及Rietveld quantification软件对材料中结晶相组成和结构进行表征.结果表明:铝铬渣和废弃镁碳砖细粉经1500℃保温2h煅烧,可以合成出镁铝尖晶石材料.当镁碳砖含量为40％,铝铬渣为60％时,合成材料微观结构中出现典型的镁铝尖晶石八面体形貌特征,结晶相发育完整,结构致密,镁铝尖晶石含量达到94％.     

Corrosion Mechanism of MgO-CaO Brick for AOD Furnace

In recent years burnt MgO-CaO brick have a-chieved a good application in AOD furnace[1].Thiswork analyzed the microstructure of residual MgO-CaObricks after being used in AOD furnace and discussedthe corrosion mechanism,which provides a theoreticalfoundat…     

Corrosion Resistance Mechanism of Magnesia Zirconia Brick to RH Furnace Slag

Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for RH furnace.The corrosion resistance of magnesia zirconia brick and fused rebonded magnesia chrome brick (short for magnesia chrome brick) to high and low basicity slag of RH furnace was comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed.The results show that:(1) because the reaction l...     

Corrosion Resistance Mechanism of MgO-CaO Refractories to Refining Slag

Corrosion resistance and penetration resistance of MgO-CaO materials with different CaO contents （22%, 42%, 49%, 53%, in mass）to refining AOD slag or VOD slag were investigated using static crucible technique by visual observation, SEM and XRD. The corrosion resistance and penetration resistance of speci-mens decrease with the increase of CaO content. This may be caused by the formation of C3S and C2S during the reactions between specimens and the slag. The formed C3S and C2S can restrain the further penetration to the matrix. The higher the CaO content, the more the C2S or C3S formed, the lower the porosity of the speci-mens, and the lower the penetration depth and corrosion rate. The corrosion resistance to AOD slag is better than that to VOD slag, because the reaction between AOD slag and the matrix is slighter than that between VOD slag and the matrix.     

Chemical Corrosion Mechanisms of Magnesite-chrome Bricks by Converter Slag

The corrosion resistance of four kinds magnesitechrome bricks against converter salg was investigated by static crucible slag tests. The microstructures of the asdelivered and tested refractories were analyzed by means of SEM and EDS. The results showed that： Different magnesite-chrome bricks have different slag resistances. Generally, the slag resiantance sequence is as follows： rebounded fused magnesite-chrome brick 〉 semi-reboun- ded magnesite-chrome brick 〉 direct-bonded magnesitechrome brick 〉 silicate bonded magnesite-chrome brick. Slag reacts with the periclase of magnesite-chrome refractories, which results in the dissoving of periclase in fayalite slag. However, the complex spinels have superior slag resistance.     

Improved properties of low-carbon MgO-C refractories with the addition of multilayer graphene/MgAl2O4 composite powders

The paper investigated the effects of different amounts (0%, 3%, 6%, 9%) of in situ multilayer graphene/MgAl₂O₄ composite powders on the slag resistance, thermal shock resistance, and oxidation resistance of low-carbon MgO-C refractories. Comparing with commercial MgAl₂O₄, the MgAl₂O₄ in in situ multilayer graphene/MgAl₂O₄ composite powders has higher lattice strain of crystal, which can trap more Mn and Fe ions, resulting in the better slag resistance. The oxidation decarbonation layer of MgO-C specimen with 3% composite powders is 9.71 mm, which is lower than not only the specimen with other contents but also specimen containing carbon black/MgAl₂O₄ powders. Moreover, the residual strength ratio of the specimen C/MA-3 was 47.47%, which is 28.5% and 8.08% higher than specimens with no additive and with carbon black/MgAl₂O₄ powders, respectively. Both improving thermal shock and oxidation resistance properties are related with the unique nano structure, multilayer graphene in situ formed between MgAl₂O₄ grains, of added composite powders. The former is due to higher strain energy consumed by multi-deflection of cracks inside the multilayer graphene/MgAl₂O₄ composite powders. And the latter is due to the higher energy of oxidation activation of multilayer graphene/MgAl₂O₄ composite powders due to effective protection of multilayer graphene by MgAl₂O₄.