MgO-ZrSiO4浇注料的渣蚀机理

对渣蚀后的MgO -ZrSiO4浇注料进行了SEM和EDAX分析。结果表明 :( 1 )反应层中的CaZrO3和方镁石形成直接结合 ;( 2 )渗透层中的ZrO2 聚集起来并呈环状包围液相 ;( 3)部分ZrO2弥散于液相中 ,提高了液相粘度。上述现象阻碍了液相的渗透 ,提高了材料的抗渗透性。     

锆英石微粉对镁质浇注料性能的影响

研究了锆英石微粉对镁质浇注料结构及性能的影响。结果表明：微粉粒径一定时,控制锆英石微粉加入量可以明显改善镁质浇注料显微结构和性能。由于MgO同ZrSiO4反应形成的ZrO2,能吸收渣中的CaO形成CaZrO3,堵塞材料中的气孔,同时提高熔海粘度,抑制了渣的渗透。     

高铝矾土-尖晶石钢包浇注料的开发与应用

采用高铝矾土和矾土基尖晶石为主要原料 ,制备了高铝矾土 -尖晶石浇注料 ,研究了硅微粉和烧结镁砂细粉的加入量对该浇注料高温抗折强度及抗渣性能的影响及新开发的防爆剂对浇注料抗爆裂性能的影响。结果表明 :加入适量的硅微粉和烧结镁砂细粉 ,可改善浇注料的强度和抗渣性 ;新型防爆剂可有效改善浇注料的抗爆裂性 ;研制的浇注料在 4 0t连铸钢包上使用 ,效果很好。     

钢包渣线用MgO-尖晶石-Cr_2O_3浇注料的研制与应用

以镁砂、电熔白刚玉、矾土熟料、尖晶石等为主要原料,研究了Ｃｒ２Ｏ３对ＭｇＯ尖晶石浇注料常温物理性能、荷重软化温度、抗渣和抗热震性的影响,开发出了ＭｇＯ尖晶石Ｃｒ２Ｏ３浇注料。在某钢厂９０ｔＲＨ精炼钢包渣线部位使用,平均一次性寿命达９６．５次     

钢包渣线浇注料基质组成及其抗渣性

采用特级高铝矾土熟料和电熔镁砂为主要原料,研究了Al2O3-MgO系浇注料中MgO/Al2O3质量比对浇注料基本性能的影响,并分析对比了基质中添加适量工业氧化格、镁锆合成料及矾土尖晶石对浇注料抗渣性的影响及其规律。结果表明：恰当控制基质中MgO/Al2O3质量比及在基质中添加适量的工业氧化铬等组分,可明显提高浇注料的抗渣性。     

氧化镁对凝胶结合氧化铝空心球浇注料性能的影响

以不同粒度氧化铝空心球为原料,以由二氧化硅微粉形成的凝胶为结合剂,制成了氧化铝空心球浇注料。在浇注料中添加电熔镁砂,研究电熔镁砂中的氧化镁对凝胶结合氧化铝空心球浇注料性能的影响。     

含ZrO_2添加剂对方镁石-尖晶石耐火材料抗渣性能的影响

采用电熔镁砂、电熔镁铝尖晶石为主要原料,用坩埚法研究了三种含ＺｒＯ２ 添加剂对方镁石－ 尖晶石耐火材料抗渣性能的影响。结果表明：引入的ＺｒＯ２ 能有效吸收渣中的ＣａＯ,形成高熔点的ＣａＺｒＯ３ 固相堵塞在气孔中,阻止了炉渣的进一步渗透,又有效地降低了ＣａＯ 对尖晶石的分解作用及ＣａＯ、ＳｉＯ２ 等对主晶相方镁石的侵蚀作用;同时,ＺｒＯ２ 的引入能促进烧结,提高高温固相直接结合率,对提高抗渣性也有着十分重要的意义。     

Use of alumina dispersant in alumina-spinel castable: Comparison between in situ and preformed spinels

The role of alumina dispersant as a flow modifier, completely replacing fume silica, on the properties of preformed and in situ spinel-containing low cement high alumina castables was investigated with variations in spinel content and granulometry. Both 10 and 20 wt.% spinel-containing compositions were prepared using preformed spinel or magnesia in alumina castable compositions with vibratable and self-flowing consistency. The castables underwent conventional processing methods and accessed for various refractory-related parameters post-heat treatments. No glassy phase was observed in the castables upon firing. The presence of self-flowing consistency led to improved characteristics. Preformed spinel-containing compositions showed improved density, strength, hot strength, and thermal shock resistance properties, whereas slag corrosion and penetration resistances were found to be higher for in situ spinel-containing castable.     

镁锆质浇注料的抗渣性研究

采用坩埚法研究了镁锆质浇注料的抗渣性.结果表明:随着配料中锆英石的增加,浇注料抗渣渗透性增强,抗渣侵蚀性降低.文中主要探讨了镁锆质浇注料抗渣渗透性机理.     

氧化镁-尖晶石浇注料的组成与性能的关系

以中档烧结镁砂、矾土基尖晶石和电熔白刚玉为主要原料,制备了不同基质组成的试样,并研究了浇注料的流动性、强度、永久线变化率、抗渣性和抗热震性。结果表明：基质的组成（特别是Ａｌ２Ｏ３／ＭｇＯ比）对浇注料的抗渣性、线变化率、抗剥落性和热震稳定性有显著影响,通过调整Ａｌ２Ｏ３／ＭｇＯ比可制得综合性能优良的氧化镁－尖晶石浇注料     

硅微粉酸碱度对镁质浇注料性能的影响

以镁砂为主要原料,使用MgO-SiO2-H2O结合体系,研究了不同酸碱度硅微粉对镁质浇注料流动性和物理性能的影响。结果表明,使用弱酸性硅微粉的镁质浇注料具有良好的流动性和较高的强度,使用中性的硅微粉的镁质浇注料具有更好的流动性保持率。     

Systemic analysis of MgO hydration effects on alumina–magnesia refractory castables

The use of magnesia sources with high specific surface area and small particle size in the Al₂O₃–MgO system can induce faster in situ spinel (MgAl₂O₄) formation in castable compositions, improving the slag corrosion resistance. However, the higher reactivity of these raw materials lead to an intensive brucite formation (followed by volumetric expansion), spoiling the castable's properties during the curing and drying steps. Considering these aspects, a systemic analysis of three magnesia sources (dead-burnt and caustic ones) was carried out in order to evaluate: (1) their hydration impact on the refractory castables properties, and (2) their bonding ability in cement-free compositions. Mechanical strength, thermogravimetric and Young's modulus tests were conducted during the castables’ curing and drying steps. According to the results, the elastic modulus measurement is an efficient tool to evaluate the magnesia hydration. The addition of proper amounts of calcium aluminate cement and/or silica fume to the castables can inhibit the crack formation and provide suitable mechanical properties. The results also show that under certain conditions, MgO can be used as a binder, replacing calcium aluminate cement and leading to a significant reduction in the castables costs with no drawbacks to their refractoriness.     

结合剂对碳化硅浇注料碳化后性能的影响

硅溶胶结合体系可以显著提高碳化硅基浇注料碳化后的热态强度。本试验利用原位反应的机理,在一定粒度级配的碳化硅颗粒中加入硅粉、硅微粉和不同的结合剂为原料,振动成型,然后经过1450℃(3h)埋炭热处理。初步研究了不同品质的结合剂(硅溶胶、铝酸钙水泥)对碳化硅基浇注料碳化后的性能,尤其是热态强度的影响。结果表明:加入少量的炭黑有助于硅溶胶结合碳化硅浇注料的高温抗折强度和热震稳定性的提高,但加入少量的炭黑对碳化反应没有明显的影响。     

Thermodynamic evaluation of spinel containing refractory castables corrosion by secondary metallurgy slag

This work addresses the thermodynamic evaluation of different spinel-containing refractory castable compositions in contact with a basic steel ladle slag (CaO/SiO₂ ∼ 9). The main differences among the castable compositions were the amount of silica fume (0 or 1 wt%), the binder source (calcium aluminate cement or hydratable alumina) and the spinel incorporation route (in situ or pre-formed). The interaction of the liquid slag with the refractory was carried out with the help of thermodynamic software (FactSage) and the applied methodology considered the changes in the slag composition due to the interaction with the castable. The theoretical results were compared with the experimental data attained by corrosion cup-tests, pointing out that the thermodynamic calculations were suitable for predicting various aspects observed in the corroded samples by SEM. Therefore, the equilibrium simulations led to parameters that indicated the corrosion resistance trends, complementing the experimental evaluation and reducing further experimental testing.     

Structure and properties of lightweight magnesia refractory castables with porous matrix

To improve the energy-saving capacity of magnesia refractory castables for working lining of high-temperature kilns, this study presents the researches on microstructure and properties of lightweight magnesia refractory castables with porous matrix fabricated by direct foaming method. The results show that formation of closed-pores in the matrix significantly enhanced high-temperature thermal insulation performance of castables with minor changes of slag corrosion resistance. The thermal conductivity of the lightweight magnesia castables at 1000 °C was below 1.2 W/m·K, which is 47.8% lower than that of the referenced magnesia castable. The increasing content of SDS (foaming agent, over 0.02 wt%) led to increments of size and number of large-sized pores, resulting in the significantly decreased density and mechanical performances. The slag resistance mechanism reveals that, in addition to intergranular penetration, the accumulation of slag and penetration between adjacent pores were the major ways of slag mass transfer in lightweight magnesia castables. In conclusion, controlling the size (below 53.2 μm), number and distribution of closed-pores in the matrix is effective to realize the coupling of high thermal insulation, mechanical properties and slag resistance for lightweight magnesia castables used in the metallurgical field.     

LF精炼钢包渣线用含铬铝镁浇注料的研制

以特级矾土、电熔镁砂、铬刚玉为主要原料制备了LF精炼钢包渣线用含铬尖晶石质浇注料,并在抗渣蚀性及抗热震性方面同现场使用的普通铝镁浇注料进行了对比。结果表明:与现场使用的铝镁浇注料相比,新研制的含铬尖晶石浇注料具有更好的抗热震性及抗渣蚀性,在济钢55t钢包上使用寿命达到79炉次。     

Slag attack evaluation of in situ spinel-containing refractory castables via experimental tests and thermodynamic simulations

Although the in situ spinel formation in alumina-magnesia refractory castables induces an expansive behavior, many investigations highlight its positive role in the corrosion resistance of such materials. Thus, this work addresses the slag attack evaluation of four designed in situ spinel-containing castables (containing hydratable alumina or calcium aluminate cement as a binder source and 0 or 1 wt% of silica fume) when in contact with a Fe_xO rich industrial slag. Corrosion cup-tests, microstructural characterization and a two-step thermodynamic simulation model were used in order to investigate the reactions taking place during the slag-refractory interactions. According to the attained results, hydratable alumina seems to be a suitable binder to improve the corrosion resistance of such castables, as it induces densification and the formation of an alumina-rich spinel phase at the slag-matrix interface. Moreover, the thermodynamic calculations matched to the experimental observations, attesting the efficiency of the proposed simulation model for the evaluation of the in situ spinel-containing castable corrosion behavior.     

The development of a thermodynamic model for Al2O3–MgO refractory castable corrosion by secondary metallurgy steel ladle slags

Alumina magnesia in situ spinel castables are used as ladle refractory lining in the steel industry. In contact with slag, they suffer degradations which limits their performance. The purpose of this article is to predict the thermochemical attack of a slag on alumina magnesia refractory using Factsage^® thermodynamic modeling. To evaluate the reliability of the thermodynamic results, a validation step was carried out, which supported that the database was well adapted to the alumina magnesia spinel system. The corrosion phenomenon was then computed for a simple to a complete system to understand the mechanism and the influence of specific oxides. The model was also compared to corroded microstructures from a steel ladle to evaluate the contribution of each constituent in the castable. The aggregates of alumina react with slag to produce monomineral layers of lime aluminates (CA6 and CA2), while complex spinels (Mg, Fe, Mn)O (Fe₂, Al₂)O₃ are formed from the reaction of the slag with the matrix of the castable. Several oxides (MnO, FeO, Fe₂O₃) from the slag contribute to the formation of the spinel structures. The microstructures of refractories used in steel ladles confirm the main conclusions and the thermodynamic approach.     

氮化硅铁、亚白刚玉和硅微粉加入量对ASC砖性能的影响

采用正交试验,研究了氮化硅铁、亚白刚玉和硅微粉的加入量对鱼雷车三脱用A l2O3-SiC-C(简称ASC)砖高温抗折强度和抗三脱渣侵蚀性的影响。结果表明:1)对ASC砖高温抗折强度影响最大的是氮化硅铁加入量,硅微粉加入量次之,刚玉加入量的影响最小;随着氮化硅铁加入量增加,Si2N2O生成量增加,试样的高温抗折强度明显增大。2)对ASC砖抗三脱渣侵蚀性影响最大的是刚玉加入量,氮化硅铁加入量次之,硅微粉加入量的影响最小;随着刚玉、氮化硅铁加入量的增加,试样的抗渣侵蚀性增强,而随着硅微粉加入量的增加,试样的抗渣侵蚀性减弱。     

TiO_2对镁铬砖抗渣蚀性的影响

利用XRD分析和光学显微镜等测试手段 ,研究了添加TiO2 对镁铬砖抗渣蚀性的影响。结果表明 :炉渣中的CaO能分解镁铬砖中的二次尖晶石而使镁铬砖损毁 ,但加入TiO2 后 ,TiO2 能优先于尖晶石中的Cr2 O3与渣中CaO反应 ,生成高熔点的CaTiO3,从而抑制CaO对砖中镁铬尖晶石的分解 ,提高了镁铬砖的抗高钙渣渣蚀能力