ZrO2对刚玉-尖晶石浇注料抗热震性能的影响

为制备具有优良抗热震性能的刚玉–尖晶石浇注料,在浇注料中加入0～9%（质量分数,下同）的氧化锆,通过测试弹性模量和残余抗折强度研究了氧化锆对刚玉–尖晶石浇注料抗热震性能的影响。利用X射线衍射和扫描电子显微镜分析了刚玉–尖晶石–氧化锆浇注料抗热震性能的影响机制。结果表明：刚玉–尖晶石浇注料的弹性模量随氧化锆加入量增加逐渐...     

ZrO2对刚玉-尖晶石浇注料抗热震性能的影响

为制备具有优良抗热震性能的刚玉–尖晶石浇注料,在浇注料中加入0～9%（质量分数,下同）的氧化锆,通过测试弹性模量和残余抗折强度研究了氧化锆对刚玉–尖晶石浇注料抗热震性能的影响。利用X射线衍射和扫描电子显微镜分析了刚玉–尖晶石–氧化锆浇注料抗热震性能的影响机制。结果表明：刚玉–尖晶石浇注料的弹性模量随氧化锆加入量增加逐渐降低,由129 GPa（未加ZrO2）降至93.6 GPa（加入9%ZrO2）,而残余抗折强度随氧化锆加入量增加而升高,经5次1 100℃水冷热震循环后,残余抗折强度保持率由59%（未加ZrO2）提高到83%（加入9%ZrO2）。提高刚玉–尖晶石浇注料抗热震性能的机制为微裂纹增韧、ZrO2粒子弥散增强和钉扎效应等多重因素共同作用。     

骨料对Al_2O_3-尖晶石钢包浇注料性能的影响

研究了三种不同骨料对Al2O3-尖晶石钢包浇注料性能的影响。结果表明：用电冶矾土刚玉骨科制得的浇注料具有较好的流动性、高温烧结性和抗渣性,但热震稳定性比电熔白刚玉有所降低。这主要与电冶矾土刚玉的组成和显微结构有关。     

低温预合成刚玉-尖晶石微粉在钢包浇注料中的应用

在对比研究1 200℃低温预合成刚玉-尖晶石复合微粉、活性α-Al_2O_3微粉流变性的基础上,研究了刚玉-尖晶石复合微粉对钢包浇注料性能的影响。结果表明:刚玉-尖晶石复合微粉悬浮液与α-Al_2O_3微粉悬浮液类似,均呈假塑性流体特性;分散剂WSM-R1的加入可显著降低刚玉-尖晶石微粉悬浮液的黏度;刚玉-尖晶石微粉可部分或全部取代α-Al_2O_3微粉作为浇注料基质的主要配料组成,以该微粉配制的刚玉-尖晶石浇注料具有良好的施工性能及体积稳定性,同时具有良好的抗热震性,较好的抗熔渣侵蚀和抗熔渣渗透性。     

尖晶石加入量对刚玉-尖晶石浇注料性能的影响

为了提高刚玉-尖晶石浇注料的高温体积稳定性和抗蠕变性,以尖晶石细粉分别替代刚玉浇注料中0、10%和21%(w)的刚玉细粉,研究了尖晶石加入量对浇注料体积稳定性、抗蠕变性和显微结构的影响。结果表明:1)尖晶石固溶氧化铝伴随的膨胀可部分抵消刚玉-尖晶石浇注料的烧结收缩,提高其体积稳定性。2)尖晶石与氧化铝之间的固溶反应有助于增强刚玉-尖晶石浇注料基质的结合程度,提高其抗蠕变性。3)尖晶石细粉加入量为21%(w)时浇注料的体积稳定性最优,尖晶石细粉加入量为10%(w)时浇注料的抗蠕变性最优。     

氧化锆对铬刚玉浇注料烧结及抗热震性能的影响

为改善铬刚玉浇注料的抗热震性能而又不显著降低其强度,在铬刚玉浇注料中加入了氧化锆微粉,采用弹性模量测定仪、X射线衍射仪、扫描电镜和压汞仪等研究了氧化锆微粉对浇注料烧结性能及抗热震性能的影响.结果表明:氧化锆微粉可促进铬刚玉浇注料的烧结.当氧化锆微粉掺量在1%～3%(质量分数,下同)时,可提高浇注料的抗热震性能且不降低材...     

尖晶石加入量对铬刚玉浇注料性能的影响

研究了尖晶石加入量对铬刚玉浇注料的烧结性能、抗折强度、抗热震性以及抗渣渗透和侵蚀能力的影响。尖晶石的加入使铬刚玉浇注料线变化率增大 ,显气孔率升高 ,常温强度略有降低。加入 2a %～ 3a %的尖晶石能明显改善铬刚玉浇注料的抗热震性。加入尖晶石后 ,铬刚玉浇注料的抗高钙、高铁渣的渗透、侵蚀能力有所下降     

尖晶石对凝胶结合氧化铝空心球浇注料性能的影响

以5～3mm、3～2mm、2～1mm、1～0.2mm粒度氧化铝空心球为原料,引入二氧化硅微粉制成凝胶结合氧化铝空心球浇注料,研究了预合成镁铝尖晶石对凝胶结合氧化铝空心球浇注料性能的影响。用各种耐火制品检测设备和仪器对引入不同量尖晶石的试样性能进行了检测。结合氧化镁-氧化铝-二氧化硅相图进行理论分析,结果发现:尖晶石的引入促进了浇注料中刚玉相的烧结,提高了凝胶结合氧化铝空心球浇注料的常温耐压强度和显气孔率,降低了浇注料的体积密度。尖晶石对凝胶结合氧化铝空心球浇注料基质具有强化作用,有利于提高浇注料的热震稳定性     

钢包用刚玉-尖晶石透气砖的研制与应用

研究了基质中MgO含量对以电熔刚玉、尖晶石为主要原料制成的刚玉 -尖晶石透气砖 (砖芯 )性能的影响 ,并比较了刚玉 -尖晶石砖与传统铬刚玉砖的性能。结果表明 :刚玉 -尖晶石砖热震稳定性优于铬刚玉砖 ,但其体积稳定性不如铬刚玉砖 ,生产中不易控制 ;工业试验表明 ,刚玉 -尖晶石透气砖 (砖芯和座砖 )优于传统铬刚玉透气砖。     

烧结刚玉骨料致密度对刚玉-尖晶石浇注料性能的影响

为了研究烧结刚玉骨料致密度对刚玉-尖晶石浇注料性能的影响,首先以工业Al₂O₃粉为原料制备不同致密度的烧结刚玉;然后以不同致密度的烧结刚玉为骨料制备刚玉-尖晶石浇注料,并研究了刚玉-尖晶石浇注料的致密度、强度、抗热震性和抗渣性等性能。结果发现：1)随着工业氧化铝粉成球坯体致密度的增大,制成的烧结刚玉的致密度和晶粒尺寸逐渐增大。2)随着烧结刚玉骨料致密度的增大,刚玉-尖晶石浇注料的需水性减小;烧后浇注料的致密度和常温强度增大,抗热震性变差。抗渣侵蚀性除采用体积密度为3.45 g·cm^-3的烧结刚玉骨料的浇注料明显较差外,其他浇注料的差别不大。3)综合考虑,烧结刚玉骨料的体积密度以3.51～3.55 g·cm^-3为佳。因此,不能片面地认为烧结刚玉的体积密度越大越好;过高的体积密度会导致耐火材料抗热震性能变差,并增加耐火材料单重。     

Effects of different additives on properties of magnesium aluminate Spinel–Periclase castable

Bauxite- and alumina-based spinels were employed as refractory aggregates, and sintered magnesia fine powder, calcium aluminate cement, microsilica, and activated α-Al₂O₃ were utilized as matrices. The effects of alumina powder, analytically pure zinc oxide, and analytically pure zirconia on the properties of magnesium aluminate spinel–periclase castables were studied. The results demonstrated that the addition of the three additives promoted the sintering of magnesium aluminate spinel–periclase castables. Simultaneously, the three additives significantly improved the high-temperature properties of the samples. The thermal shock resistance of the alumina powder sample increased by 200%, that of the pristine zinc oxide sample by 75%, and that of the zirconia sample by 125%. The additives effectively improved the thermal shock resistance of the magnesium aluminate spinel–periclase castable. In addition, the slag resistance depths of the samples with alumina powder and zirconia were 41% lower than that of the sample without additives, which significantly improved the slag resistance of the magnesium aluminate spinel–periclase castable.     

锆刚玉加入对刚玉-尖晶石浇注料性能的影响

在刚玉-尖晶石浇注料的配比组成中分别加入ZrO2质量分数为28.46%和38.47%的两种电熔锆刚玉颗粒,研究了电熔锆刚玉颗粒的粒度(5～3、3～1和1～0.5 mm)、加入量(质量分数分别为3%、5%和8%)对刚玉-尖晶石浇注料的加热永久线变化率、烧后常温抗折强度、高温抗折强度及热震后弹性模量的影响,并观察了试样的显微结构。结果表明:1)试样的加热永久线变化率随锆刚玉粒度的增大而增大,随锆刚玉加入量的增多而增大,引入锆刚玉Z40的试样的加热永久线变化率基本上比引入锆刚玉Z25的大;2)烧后试样的常温抗折强度、高温抗折强度和弹性模量均以空白试样的为最大,均随锆刚玉粒度的减小而增大,随锆刚玉加入量的增多而减小;3)在刚玉尖晶石浇注料中适当加入锆刚玉而产生微裂纹,尽管降低了材料的强度和弹性模量,但对提高抗热震性有一定的积极作用。     

Effect of zirconia particle size on the properties of alumina-spinel castables

The industrial application of alumina-spinel refractory castables has crucial requirements on the service performance. Thus, the effects of different sized desilicated zirconia particles on the castables microstructure, thermal-mechanical properties and high temperature elastic modulus have been investigated. The zirconia particle sizes were varied from 1000 µm to 2.5 µm (d₅₀). It was observed that the finer (below 88 µm) zirconia particles were beneficial to improve the cold modulus of rupture (CMOR) and the hot modulus of rupture (HMOR), but could not effectively enhance the thermal shock resistance. Fine zirconia particles can homogeneously disperse in the matrix and significantly promote the sintering process. Accompanied with the phase transformation of zirconia, both the high density of matrix cracks and the strong ceramic bonding (between the coarse grains and the matrix) were found in the refractory castables, which was responsible for an increase of CMOR. However, the binding characteristic could also give rise to the high stored elastic energy that was adverse to the thermal shock resistance, and the excessive amount of preexisting matrix cracks could induce more microdamage during the thermal shock. Additionally, it was proposed that the second-phase dispersion reinforcement and the highly ceramics bonding resulted in the superior HMOR when introducing fine ZrO₂ particles.     

陶瓷梗对致密浇注料性能的影响

对比研究了添加莫来石质陶瓷梗和不锈钢纤维分别对刚玉质超低水泥浇注料和高铝质超低水泥浇注料性能的影响 ,并从显微结构分析了其影响机理。研究表明 :莫来石陶瓷梗能显著改善烧成后致密浇注料的抗热震性和体积稳定性 ;而含不锈钢纤维的浇注料烧成后 ,纤维氧化成氧化铁和氧化铬 ,促进了烧结以及纤维与基体之间的结合 ,使浇注料的刚性增加 ,高温抗折强度提高 ,但抗热震性下降 ,同时 ,高温下钢纤维氧化生成更大体积的氧化铁 ,导致了浇注料本体的膨胀 ,使其烧成线变化增加。     

Study of the castable selection for blast furnace blowpipe

The contradictory properties required of castable refractories makes selecting castable refractories for industrial applications challenging. This paper seeks to describe the material selection for a blast furnace blowpipe application that is subjected to sudden temperature changes and must prevent heat loss. Three commercial high alumina castables containing andalusite or mullite from different manufacturers were characterized. Thermal shock damage resistance was evaluated using thermal shock damage resistance theory and experiments. The castables’ coefficient of thermal expansion was estimated using quantitative X-ray diffraction. Crack propagation resistance was measured using the work-of-fracture technique. Thermal shock damage was experimentally evaluated by measuring the modulus of elasticity and rupture prior to and after thermal cycles. Ultimately, the microstructure of the castables was related to the thermal shock damage behavior by estimating the aggregate size and the fracture toughening mechanisms using light optical and scanning electron microscopes. Heat loss was evaluated by calculating the blowpipe shell temperature using a one-dimensional steady-state heat conduction model. The best commercial castable refractory for blowpipe showed high thermal shock damage resistance and low thermal conductivity. The results in this study agreed with thermal shock damage resistance parameters and showed a correlation between coarse microstructure with large aggregate and higher thermal shock damage resistance.     

Al_2O_3－SiC－C质浇注料抗热震性和抗渣铁侵蚀性的研究

对新研制的Ａｌ２Ｏ３－ＳｉＣ－Ｃ质浇注料和现用出铁沟料的抗热震性和抗渣铁侵蚀性进行了研究、结果表明，该材料具有较高的抗渣铁侵蚀能力和较好的抗热震稳定性。调节Ｓｉ与Ｃ的比例可生成高强度、耐渣蚀的纤维状ＳｉＣ。     

Improvement of Durability of Purging Plugs Using MgO Micropowder for Refining Ladles

To modulate the matrix of purging plugs, MgO micropowder was introduced as a replacement to magnesia powder in alumina–magnesia castables, and the effect of MgO micropowder on the properties of alumina–magnesia castables and the possibility of developing chrome‐free castables were investigated. Experimental results showed that the introduction of MgO micropowder resulted in an improvement in the volume stability, strength, and thermal shock resistance of alumina–magnesia castables due to its high surface energy and small particle size. However, excessive amounts of MgO micropowder led to a lower densification, and there was a slight degradation in the performance of the alumina–magnesia castables. The slag resistance of the prepared alumina–magnesia castables was significantly better than that of the alumina–chrome castables. Microstructure and energy spectrum analysis showed that the formation of a solidified reaction layer, mainly consisting of spinel and CaAl₁₂O₁₉, was the major cause of the observed difference in slag resistance. In addition, the alumina–magnesia castables had a lower linear thermal expansion coefficient than that of the alumina–chrome castables at each experimental temperature, which effectively decreased the thermal stress during its service period, thus exhibiting good thermal shock resistance.     

Effect of the calcined andalusite aggregates on the micro-crack formation and thermal shock resistance of mullite castables

The effect of calcined andalusite aggregates on the micro-crack formation and thermal shock resistance of mullite castables was investigated and analyzed. The mullite castables were prepared from andalusite aggregates calcined at high temperatures. The results show that the micro-cracks from the transformation of andalusite to mullite can effectively relieve thermal stress, improving the thermal shock resistance of mullite castables. The micro-cracks generated decreased with increasing calcine temperatures of the andalusite aggregates. When the calcine temperature was increased from 1300 °C to 1500 °C, the thermal shock resistance of mullite castables was found to continuously increase. However, the thermal shock resistance of mullite castables with the andalusite aggregates calcined at 1600 °C is lower than those with the andalusite aggregates calcined at 1500 °C.     

Al2O3-SiC-C质湿式喷射浇注料的研究和应用

以高纯莫来石、碳化硅、SiO2微粉、Al2O3微粉、纯铝酸钙水泥、白刚玉细粉和球沥青等为原料,研究了q值为0.23、0.25、0.27、0.29和0.31时湿式喷射浇注料的流变性能;进一步研究了q值为0.27时,SiC加入量(质量分数分别为12%、15%、18%、21%)对其流变性能、常温物理性能和高温抗折强度、抗热震性能、抗渣侵蚀性能的影响。结果表明:根据Andreassen方程,当q=0.27时,配制的浇注料具有较好的流变性能;加水量为6.5%(w)时,研制浇注料的流变性能类似于宾汉姆流体,适于管道输送;SiC加入质量分数为18%时,浇注料具有较高的高温抗折强度、抗渣侵蚀性能和抗热震性能;经对鱼雷罐和出铁沟的喷补使用证明,研制的湿式喷射浇注料施工性能好,使用性能优异。     

改性石墨对矾土基浇注料性能的影响

分别采用Al_2O_3涂层处理法和石墨造粒法改善石墨的润湿性,并将改性处理后的石墨引入到矾土基浇注料中,研究了含改性石墨的矾土基浇注料的性能。结果表明:Al_2O_3涂层对石墨的改性效果不明显,而石墨造粒的改性效果较好;与未处理鳞片石墨相比,造粒石墨中的石墨以微粒的形式分散于浇注料中,使浇注料的需水量大幅度降低,从而使得试样的结构致密,高温抗折强度较高,抗热震性较好。