Effect of Bauxite Aggregate on Properties of AI203-SiC-C lron Trough Castables

A1203-SiC-C iron trough castables were prepared using high alumina bauxite clinker GL-90 （ 〉 1 mm ） or homogenized bauxite GL-88 to replace the traditional brown corundum aggregates （ 〉 1 mm ） to reduce the cost of iron trough castables. Effects of the two bauxite aggregates on properties of iron trough eastables were investigated. The results show that the two kinds of bauxite affect flowability, bulk density, strength and slag corrosion resistance of trough castables differently. Compared with homogenized bauxite, high alumina bauxite clinker is more suitable to substitute brown corundum. The castables prepared from the bauxite clinker have similar performances with those prepared from brown corundum, especially used in medium or small blast furnaces with weak thermal impact and lower temperature hot metal. However, in large blast furnaces with severe thermal impact and high temperature hot metal, the performances of the two castables are significantly different. So it is suggested to use the brown corundum based castables in the front gyral zone of the slag skimmer.     

矾土骨料对Al2O3-SiC-C铁沟浇注料性能的影响

为降低铁沟浇注料的原料成本,以粒度>1 mm的高铝矾土熟料GL-90和矾土均化料GL-88分别替代常规棕刚玉质Al2O3-SiC-C铁沟浇注料中>1 mm的棕刚玉颗粒,研究了这两种不同矾土骨料对铁沟浇注料的影响。结果表明:不同矾土骨料对铁沟浇注料的流动性、体积密度、强度以及抗渣侵蚀性均有不同程度的影响。相对矾土均化料而言,品位较高的高铝矾土熟料更适合作为铁沟浇注料中棕刚玉的替代品,以其为主要骨料制成的铁沟浇注料,其各项性能指标与以常规棕刚玉质铁沟浇注料的更为接近,而且在铁水温度不高、热冲击较小的中小型高炉上,这种铁沟浇注料与棕刚玉质铁沟浇注料的使用效果差别不大;而在铁水温度较高、热冲击大的高炉上,与棕刚玉质的使用效果差别较大,尤其是在撇渣器前端回旋区,应尽量使用棕刚玉质的铁沟浇注料。     

Effect of Treated Graphite on Properties of Al_2O_3-SiC-C Castables

Al2O3-SiC-C castables with 2% pitch or 2%,4% and 6% treated graphite,respectively,were prepared based on the basic formulation of traditional Al2O3-SiC-C castables. The flowability of castables,and bulk density,volume stability,strength,oxidation resistance and slag resistance of specimens fired at 110 ℃,1 100 ℃ and 1 500 ℃ respectively were comparatively studied. The results showed that:(1) With carbon source changing from pitch to treated graphite and the increase of treated graphite addition,water additi...     

复合抗氧化剂加入量对Al2O3-SiC-C浇注料性能的影响

以电熔棕刚玉为骨料,电熔棕刚玉粉、活性α-Al2O3微粉、黑碳化硅粉、球状沥青、SiO2微粉、纯铝酸钙水泥等为基质料,配以质量分数为2%、2.3%、2.6%、2.9%的复合抗氧化剂,搅拌均匀制备成Al2O3-SiC-C质浇注料。外加5%(w)的水搅拌3~5 min后,检测浇注料的流动性;经振动成型、养护、脱模、干燥后,于1 500℃空气气氛中热处理3 h,测定热处理后试样的质量损失率、体积密度、显气孔率、常温耐压强度、常温抗折强度和抗热震性。结果表明:随着复合抗氧化剂加入量(w)从2%增加到2.9%,浇注料的流动性变化不大并且保持较高的水平,显气孔率、体积密度和常温强度变化不大,质量损失率从1.14%减小到0.35%,氧化层厚度逐渐减小;复合抗氧化剂加入量为2.9%(w)的试样热震后耐压强度仍保持在70 MPa左右,具有较好的抗热震性。     

硅微粉对Al2O3-SiC-C质铁沟料的性能影响

本文以棕刚玉、碳化硅粉、氧化铝微粉、纯铝酸钙水泥(Secar71)等原料制备了Al2O3-SiC-C(ASC)质铁沟浇注料,探讨了低硅微粉加入量(质量分数分别为0、0.5％、1％、1.5％)对铁沟浇注料性能的影响.研究结果表明:在110℃烘干24 h和在1450℃煅烧保温3h后,随着硅微粉加入量的增加,铁沟料加水量逐渐减小,显气孔率呈现先减小后增大的趋势,体积密度的变化趋势与显气孔率的正好相反,常温抗折强度及耐压强度呈现逐渐增强的趋势,加入1.5％硅微粉的试样线膨胀系数比1％试样的大.综合分析ASC铁沟浇注料在高炉使用过程中各方面的性能要求,在现有颗粒级配工艺下,低硅微粉较为合适的含量为1.0％.     

结合剂对氧化铝-碳化硅-碳质铁沟浇注料力学性能和显微结构的影响

分别以水泥、氧化镁-硅灰和硅溶胶三种结合剂制备了氧化铝-碳化硅-碳铁沟浇注料,借助相关测试标准和SEM、EDS、XRD等测试手段对比研究了三种浇注料的力学性能、显微结构和物相组成.研究结果表明:以水泥和硅溶胶结合的浇注料常温强度较大,以氧化镁-硅灰为结合剂的浇注料常温强度最小;硅溶胶为结合剂浇注料高温抗折强度最大,氧化镁-硅灰为结合剂最小.原因在于:尽管以水泥和硅溶胶为结合剂的浇注料在高温烧成时都生成莫来石,但以水泥结合试样中只是在基质中部分生成莫来石晶体,而以硅溶胶为结合剂试样由于硅溶胶分散性好,脱水后微粒活性更高,在试样中均匀生成了大量交错分布的莫来石晶体,且长径比更大,因此显著提高了高温抗折强度;以氧化镁-硅灰为结合剂的浇注料高温生成镁铝尖晶石、镁橄榄石和堇青石,由于镁铝尖晶石促进了碳化硅的氧化,使得结构疏松,强度降低.     

Effect of Pyrophyllite Particle Size on Properties of AI_2O_3-SiC-C Bricks for Iron Ladles

The Al2O3-SiC-C bricks for iron ladles were prepared using bauxite,fused corundum,pyrophyllite,SiC powder and flake graphite as main starting materials, and phenolic resin as binder. The effect of pyrophyllite particle size on permanent change in dimensions,cold crushing strength,oxidation resistance,and corrosion resistance of Al2O3-SiC-C bricks was investigated. The results show that with the decrease of the pyrophyl-lite particle size,the permanent change in dimensions of Al2O3-SiC-C bricks decreases, cold crushing strength increases,the oxidation resistance at 1 400 ℃ increases,and the corrosion resistance at 1 500 ℃ decreases.     

硅溶胶结合Al2O3-SiC-C铁沟浇注料的力学性能研究

为了研究硅溶胶结合Al2O3-SiC-C材料的力学性能,以电熔棕刚玉和碳化硅为主要原料,硅溶胶为结合剂,制备了Al2O3-SiC-C铁沟浇注料,研究了其在110、300、500、700、900、1 100、1 300、1 450℃热处理后的常温物理性能和高温(1 400℃)抗折强度,并借助XRD、SEM等进行物相和显微结构分析。结果表明:随着热处理温度的升高,试样常温强度增加,烧后线变化率增大,体积密度先减小后增大,显气孔率先增大后减小,转折温度在700℃;高温抗折强度超过6 MPa。其原因在于:在中低温下,硅溶胶脱水形成—Si—O—Si—凝胶网络结构,保证了浇注料的中低温强度,700℃时因试样大量脱水而使得显气孔率最大,体积密度最小;在高温下,试样中因形成大量纤维状莫来石而为浇注料提供了较高的常温强度和高温强度。     

氮化硅铁对Al2O3-SiC-C系铁沟浇注料性能的影响

为了解决Al2O3-SiC-C系铁沟浇注料在高温使用过程中易氧化的问题,以棕刚玉颗粒、致密刚玉细粉、碳化硅颗粒和细粉、球状沥青、硅粉、Secar 71水泥、氮化硅铁等为原料,制备了Al2O3-SiC-C系铁沟浇注料,并研究了添加5%(w)氮化硅铁对该浇注料施工性能、物理性能、抗氧化性的影响,同时分别采用静态抗渣和回转抗渣试验对抗渣性能进行评价。结果表明:1)与不加氮化硅铁的常规铁沟浇注料相比,添加氮化硅铁的铁沟浇注料的常温强度略低,但是同样具备良好的施工性能和足够的脱模强度;2)添加氮化硅铁的铁沟浇注料具有较高的高温抗折强度和高温抗氧化性能;3)添加氮化硅铁的铁沟浇注料具有良好的静态抗渣能力,但是在强氧化环境和热态冲蚀同时作用的铁沟部位,不建议使用含氮化硅铁的Al2O3-SiC-C材料。     

Preparation of Microporous Corundum and Its Effect on Properties of Al_2O_3-MgO Castables

Based on the pore size design of microporous aggregate by numerical simulation applying porous media model,α-Al2O3 micropowder,industrial Al2 O3fine powder,α-Al2O3 micropowder ＋ CaCO3 fine powder were used as starting materials,respectively,to prepare three microporous corundum aggregates specimens,named as A1,A2 and A3.Two lightweight Al2O3-MgO castables were prepared by selecting A1 or A3 as aggregate with O.6 μm of average pore size,then performances of castables with microporous corundum aggregates and castables with tabular corundum aggregates were compared.The results show that：（1） the microporous corundum aggregates with bulk density of 3.1-3.5 g · cm-3,apparent porosity of 5％,closed porosity of 8％-13％,and smaller thermal conductivity at 800 ℃ than tabular corundum,can be prepared by sintering at above 1 800 ℃ ; （2） compared to normal Al2 O3-MgO castables,the two lightweight Al2O3-MgO castables have lower bulk density and higher apparent porosity;lower change rate in dimensions and higher strength firing at 1 500 ℃ ; and lower thermal conductivity at 600 and 800 ℃ ; （3） compared to normal Al2O3-MgO castables,Al2O3-MgO castable with A1 has higher penetration index,and that with A3 has higher corrosion index and lower penetration index.     

Effect of Raw Bauxite Addition on Thermal Behaviour of Ultra-low Cement Al_2O_3-SiO_2 Castables

This work investigated the thermo-gravimetric(TG) change and explosion resistance of ultra-low cement Al2O3-SiO2 castables added with 0,5%,10%,15% and 20% of ≤74 μm raw bauxite powders containing 72.8% Al2O3,respectively.The castables were prepared using white fused alumina as aggregate,powders of white fused alumina,fused mullite,α-Al2O3 ultrafines,3% CA cement and 5% microsilica as the matrix portion.TG change of the castables was investigated by a thermo-gravimetric analyzer for large size specimen.When ...     

Effect of Andalusite on Properties of Homogenized Bauxite Based Al_2O_3-SiC-C Castables

In this study,in order to evaluate the performance of homogenized bauxite,two Al_2O_3-SiC-C castables were prepared using homogenized bauxite and brown fused corundum as aggregates,respectively. 5 mass%andalusite was introduced into the two castables so as to research the effect and mechanism of andalusite in Al_2O_3-SiC-C castables. The results showed that:(1) compared with the brown fused corundum based castables,the homogenized bauxite based castables had higher cold strength after heat treatment,but lower hot modulus of rupture;(2) addition of 5 mass% andalusite could enhance the cold and hot modulus of rupture,improve the thermal shock resistance,and optimize the microstructure of specimens;( 3) the mullitization of andalusite was not obvious in the castables fired at 1100-1400℃.     

硅粉对硅溶胶结合Al_2O_3-SiC-C浇注料性能的影响

以特级矾土熟料(5~3、3~1 mm)、棕刚玉(≤1 mm)、SiC(≤1 mm)、球状沥青(1~0.5 mm)、电熔白刚玉(≤0.074 mm)、活性α-Al2O3微粉、SiO2微粉、硅粉(d50=20.81μm)为原料制备Al2O3-SiC-C浇注料,分别以质量分数为0、1%、2%、3%、4%、5%和6%的硅粉等量替代白刚玉粉,研究了硅粉对浇注料常温物理性能和抗氧化性能的影响,并采用Factsage、SEM和EPMA等手段对试样进行热力学分析和显微结构分析。结果表明:1)随着硅粉含量的增加,试样的显气孔率逐渐降低,体积密度先增大后减小,常温强度明显提高。2)硅粉可以提高浇注料的抗氧化性能,在硅粉加入量为4%(w)时,其抗氧化性能最好。3)抗氧化试验后,试样边缘部位原位反应生成的莫来石堵塞了气孔,使得试样边缘结构致密;试样过渡区域有少量的莫来石和SiO2生成,封闭了表面的气孔,进一步阻止了氧气的进入;试样中心区域有少量晶须状的SiC生成,填充在骨架结构中,起强化增韧的作用。     

电熔镁砂加入量对Al2O3-SiC-C浇注料性能的影响

以电熔棕刚玉颗粒(粒度为5~3 mm、3~1 mm,≤1 mm)、电熔白刚玉细粉(≤0.088 mm)、SiC颗粒(≤1 mm)和细粉(≤0.088 mm)、电熔镁砂细粉(≤0.088 mm)、活性α-Al2O3微粉、SiO2微粉、Si粉和球状沥青为主要原料,以纯铝酸钙水泥为结合剂,配制成电熔镁砂细粉加入量(质量分数)分别为0、3%、6%、9%、12%的出铁沟用Al2O3-SiC-C浇注料,经振动成型、养护、脱模、110℃24 h烘干后,分别于1 100℃3 h、1 450℃3 h热处理,测定处理后试样的体积密度、显气孔率、烧后线变化率、抗折强度、抗高炉渣侵蚀性和抗氧化性,并分析其物相组成和显微结构。结果表明:随着电熔镁砂加入量的增加,试样的显气孔率提高,体积密度、抗折强度和抗氧化性降低,抗渣性变化不大;1 450℃3 h处理后试样物相主要由3C-SiC、6H-SiC、刚玉、方镁石以及反应生成的尖晶石和莫来石组成,且随着电熔镁砂加入量的增加,尖晶石和莫来石的生成量也增加;在侵蚀面附近,刚玉颗粒边缘生成了厚度约80μm的尖晶石层。     

Effect of Al_2O_3-SiC Composite Powder on Properties of Al_2O_3-SiC一C Bricks

Al2O3- SiC- C specimens were prepared using white fused corundum( 3- 1,≤1 and ≤0. 044 mm),Al2O3- SiC composite powders( d50≤5 μm),α-Al2O3micropowder( d50= 1. 2 μm),SiC powder( ≤0. 044mm),flake graphite( ≤0. 088 mm),Si powder( d50= 42. 8 μm) and B4C powder( d50≤10 μm) as main starting materials,and thermosetting phenolic resin as binder. 4%,8%,12% and 16%( in mass,the same hereinafter) of Al2O3- SiC composite powders substituted the same quantity of α-Al2O3micropowder + SiC powder.Effects of composite powder additions on apparent porosity,bulk density,cold modulus of rupture,cold crushing strength,hot modulus of rupture( 1 400 ℃),therma shock resistance( 1 100 ℃,water quenching) and oxidation resistance( 1 000 and 1 500 ℃) of Al2O3- SiC- C specimens after 180 ℃ curing,1 000 ℃ 3 h carbon-embedded firing and 1 500 ℃ 3 h carbon-embedded firing,respectively,were researched. The results indicate that:( 1) with the increase of Al2O3- SiC composite powder,cold strengths of the cured specimens decline,those of the specimens fired at 1 000 ℃ change a little,and those of the specimens fired at 1 500 ℃ change a little except for an obvious improvement of cold crushing strength;( 2) with the increase of Al2O3- SiC composite powder,hot modulus of rupture at 1 400 ℃ decreasesand thermal shock resistance enhances significantly;( 3) when Al2O3- SiC composite powder addition is4%,the oxidation resistance at 1 500 ℃ is the best,and the reason may be the composite powder is finer and more active,which is beneficial to form dense mullite protective layer to retard the O2diffusion into the specimens.     

Effect of Pelletized Graphite Addition on Properties of Al_2O_3-SiC-C Castables

Al_2O_3-SiC-C castables with pelletized graphite addition of 0,2%,4% or 6%( by mass,the same hereinafter) were prepared using brown fused corundum( 8- 5,5- 3 and 3- 1 mm),dense fused corundum( ≤1 and 0. 045 mm) and Si C( ≤1 and ≤0. 064mm) as main starting materials with mass ratio of aggregate∶ matrix = 71∶ 29,2% silicon powder and 0. 4%B4C as antioxidants,and pelletized graphite as carbon source. Effect of pelletized graphite addition on physical properties,oxidation resistance,slag resistance and thermal shock resistance of Al_2O_3-SiC-C castables was researched. The results show that: with the increase of pelletized graphite addition,the required water amount of castables increases,the bulk density and strength reduce;with 4% pelletized graphite,the castable performs the best oxidation resistance; the increase of graphite is beneficial to the improvement of slag penetration resistance and corrosion resistance; with 6% pelletized graphite,the thermal shock resistance is the best.     

Al2O3-SiC复相粉对Al2O3-SiC-C材料性能的影响

以电熔白刚玉(3～1、≤1、≤0.044 mm)、Al2O3-SiC复相粉(d50≤5μm)、α-Al2O3微粉(d50=1.2μm)、SiC粉(≤0.044 mm)、鳞片石墨(≤0.088 mm)、Si粉(d50=42.8μm)和B4C(d50≤10μm)为主要原料,热固酚醛树脂为结合剂,研究了分别用4%、8%、12%、16%质量分数的Al2O3-SiC复相粉等比例取代α-Al2O3微粉和SiC细粉对Al2O3-SiC-C试样在180℃固化后和1 000、1 500℃埋焦炭热处理后的显气孔率、体积密度、常温抗折强度、常温耐压强度、高温抗折强度(1 400℃)、抗热震性(1 100℃,水冷)以及抗氧化性(1 000、1 500℃)的影响。结果表明:随Al2O3-SiC复相粉加入量的增加,试样经180℃固化后常温性能下降,1 000℃热处理后常温性能变化不大,1 500℃热处理后除耐压强度显著提高外,其余各项常温性能变化不大;而高温抗折强度下降,抗热震性明显提高,试样经1 500℃氧化后的抗氧化性以加入4%质量分数复相粉的最佳。其原因可能是由于该复相粉的粒度更细,反应活性更高,其氧化层中更易生成莫来石,形成表面致密层从而有效地阻碍氧气向材料内部扩散。     

铝电解烟道灰在Al_2O_3－SiC－C系耐火材料中的应用

以铝电解烟道灰代替Ａｌ２Ｏ３－ＳｉＣ－Ｃ系耐火材料中的工业氧化铝和石墨，采用正交实验的方法，探讨了各种物料加入量对耐火材料性能的影响。实验表明：烟道灰、ＳｉＣ．抗氧化剂的加入量（％）分别为１３～１４、９～１０、４左右。     

Effects of Electro-fused Magnesia on Properties of Al_2O_3-SiC-C Castable

Al2O3-SiC-C castables for iron trough with fused magnesia powder (0, 3%, 6%, 9% and 12%) were prepared with brown fused corundum particles (5-3 mm, 3-1 mm, ≤1 mm), white fused corundum powder (≤0.088 mm), SiC particle (≤1 mm) and powder (≤0.088 mm), fused magnesia powder (≤0.088 mm), reactive α-Al2O3 micropowder, ultrafine SiO2, Si powder and sphere pitch as main starting materials and calcium aluminate cement as binder. The specimens were fired at 1 100 ℃ and 1 450 ℃ for 3 h after vibrating moulding, curin...     

硅铝凝胶粉结合SiAlON增强A1_2O_3-SiC-C浇注料

以电熔致密刚玉和碳化硅为骨料,硅铝凝胶粉、氮化硅粉、硅粉为细粉,制成SiAlON增强Al2O3-SiC-C浇注料,研究了硅铝凝胶粉的加入量分别为1%、3%、5%(质量分数,下同)时对此浇注料的烧结性能、力学性能的影响。结果表明:采用硅铝凝胶粉取代纯铝酸钙水泥作结合剂,可使SiAlON增强Al2O3-SiC-C浇注料在经中温、高温热处理后的常温抗折强度及耐压强度较大提高,中温、高温强度提高幅度更大。另外,随着硅铝凝胶粉加入量的增加,浇注料的常温及高温强度呈先增大而后减小的趋势。由X射线衍射和扫描电镜分析结果可知,硅铝凝胶粉的加入既有利于降低βSiAlON的生成温度,又可以减少材料中的低熔物质。分布均匀、发育良好的粒状βSiAlON的形成是SiAlON增强Al2O3-SiC-C浇注料较水泥结合浇注料强度高的根本原因。