微孔刚玉的制备及其对铝镁浇注料性能的影响

在采用多孔介质模型进行微孔骨料孔径数值模拟设计的基础上,分别以α-Al2O3微粉、工业Al2O3细粉、α-Al2O3微粉+CaCO3细粉为原料,通过湿磨工艺分别制备了三种微孔刚玉骨料A1、A2、A3,并分别以平均孔径约0.6μm的A1和A3两种微孔刚玉为骨料制成轻质铝镁浇注料,与采用板状刚玉骨料制备的普通铝镁浇注料进行了性能对比。结果表明:1)以α-Al2O3微粉、工业Al2O3细粉等为主要原料,在1 800℃以上烧结可获得体积密度为3.1~3.5 g·cm-3、显气孔率约5%、闭口气孔率为8%~13%的微孔刚玉骨料,其800℃的热导率比板状刚玉的小;2)与普通铝镁浇注料相比,两种轻质铝镁浇注料的显气孔率较大,体积密度较小,1 500℃处理后的强度较高,线变化率较小,在600和800℃时的热导率明显较小;3)与普通铝镁浇注料相比,含A1骨料的铝镁浇注料渗透指数偏大,含A3骨料的铝镁浇注料的侵蚀指数稍大,但渗透指数小。     

纳米氧化锆增韧刚玉质陶瓷蓄热体的性能研究

以板状刚玉细粉、活性α-Al2O3微粉为主要原料,脱硅锆或不同Y2O3含量的纳米ZrO2为添加剂,CMC为结合剂,在200 MPa液压压力下半干法压制成型,经1550℃2 h烧成,制备了刚玉质陶瓷蓄热体试样,检测烧后试样的常温抗折强度、常温耐压强度、抗热震性,并借助SEM分析了其显微结构。结果表明:引入纳米ZrO2与引入脱硅锆相比,纳米ZrO2作为第二相粒子弥散分布于刚玉质陶瓷蓄热体的内部,提高了其强度和抗热震性;纳米ZrO2的增韧效果与其引入时的晶型有关,引入的ZrO2全部为立方晶型时不能发生相变增韧,仅发生微裂纹增韧,增韧效果小,而引入的ZrO2存在适量四方和单斜晶型时通过相变增韧和微裂纹增韧的共同作用提高了刚玉质陶瓷蓄热体的韧性。     

氧化铝微粉与减水剂对刚玉质浇注料施工性能的影响

研究了减水剂(包括六偏磷酸钠和萘系、三聚氰胺类及聚羧酸盐类3类减水剂)、氧化铝微粉(包括烧结氧化铝微粉和活性氧化铝微粉)对纯铝酸钙水泥结合刚玉质浇注料的流动性能和力学性能的影响。结果表明:1)氧化铝微粉的平均粒度对浇注料的流动度有较大的影响,在一定范围内,粒度越粗,浇注料的初始流动性越小,可工作时间越短。2)氧化铝微粉中可溶性碱性氧化物的含量对浇注料的施工性能和可工作时间有一定的影响。3)减水剂既影响浇注料的需水性,还影响浇注料的强度发展,必要时需引入缓凝剂或者促硬剂进行调节。4)综合比较萘系、三聚氰胺类及聚羧酸盐类3类减水剂,以聚羧酸盐类减水剂的减水效果较好。     

微孔刚玉和板状刚玉耐火材料的抗渣性对比

分别以微孔刚玉和板状刚玉为原料,按粒度为3～1、≤1和≤0.088 mm的原料质量分数分别为35%、30%和35%配料,外加4%的纸浆废液作结合剂,压制成坩埚试样,在1 600℃保温3 h烧成后,加入10 g碱度为3.2的转炉终渣,在1 600℃保温3 h条件下进行抗渣试验,然后测量并计算试样的侵蚀指数和渗透指数,并对侵蚀后试样进行了形貌观察、元素面分布分析和微区成分分析.结果表明:两种刚玉质耐火材料的抗渣侵蚀性基本相同,但是,以微孔刚玉制备的试样的抗渣渗透性却比以板状刚玉制备的差.     

刚玉质耐火材料高温耐冲蚀磨损性能的研究

以不同组成的刚玉质耐火材料作为试验样品,用ABR-1450A型高温耐磨试验仪分别研究了水泥加入量(w)为2%、4%、6%,硅微粉加入量(w)为2%、3%、4%,冲蚀角为30°、45°、60°,磨料粒度为1~3mm、2~5mm以及冲蚀温度为600℃、800℃、1000℃、1200℃时对刚玉质耐火材料高温耐冲蚀磨损性能的影响。结果表明:随材料中纯铝酸钙水泥加入量的提高,材料的高温耐磨性降低;随硅微粉加入量的提高,材料的高温耐磨性提高;提高冲蚀温度、增大磨料颗粒尺寸和增大冲蚀角都可以增加对耐火材料的磨损。     

纳米Al2O3对刚玉质耐火材料结构和性能的影响

在以板状氧化铝、电熔白刚玉、烧结氧化铝微粉为主要原料的刚玉质耐火材料中通过机械混合法和前驱体(铝溶胶)法引入0、0.5%、1.0%、1.5%和2.0%(质量分数,下同)的纳米Al2O3,混练均匀后,以180MPa的压力压制成125mm×25mm×25mm的试样,于120℃干燥12h后,在硅钼棒电炉中于不同温度(1400℃、1500℃、1600℃和1650℃)下保温4h烧成,然后测定烧成后试样的体积密度、显气孔率、常温抗折强度和高温抗折强度,并采用SEM分析烧成后试样的显微结构。结果表明:以前驱体法引入纳米Al2O3对材料性能的优化效果明显好于机械混合法;在相同的工艺条件下,加入1.5%的纳米Al2O3对提高烧成试样的体积密度、常温抗折强度和高温抗折强度作用最明显;当纳米Al2O3加入量超过1.5%时,烧成试样的强度迅速降低。     

莫来石──刚玉质匣钵研制

依据陶瓷工业烧成工艺要求,结合引进线进口匣钵特点,研制了耐火度＞１７００℃,抗折强度大于７．０ＭＰａ荷重软化点＞１５００℃,并在陶瓷烧成中能长寿命使用的匣钵。研究了莫来石结晶状态和显微结构对匣钵性能的影响。     

以微孔刚玉-尖晶石骨料替代刚玉骨料制备刚玉-尖晶石浇注料

为提高钢包工作衬用刚玉-尖晶石浇注料的保温性能,以微孔刚玉-尖晶石骨料部分或全部替代同粒级的烧结刚玉骨料,制备了刚玉-尖晶石浇注料,对比研究了不同骨料对浇注料的体积密度、气孔率、力学强度、热导率、抗渣性等的影响。结果表明：采用微孔刚玉-尖晶石骨料部分或全部替代同粒级的烧结刚玉骨料制备的刚玉-尖晶石浇注料,其体积密度和热导率均明显降低,抗渣性能与传统烧结刚玉骨料制备的浇注料相当。将其用于钢包工作衬,有助于钢包减重,提高钢包保温性能。     

刚玉质自流浇注料流动性能的研究和应用

以棕刚玉为主要原料,研究了减水剂、活性氧化铝微粉、硅微粉和水泥对刚玉质自流浇注料流动性能的影响.研究结果表明:通过选择合适的减水剂和微粉及水泥加入量,可以获得自流性能良好的浇注料,并将其应用于某钢厂80吨精炼钢包包底,使用寿命和座砖同步,满足了生产要求.     

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.     

Preparation,Performance and Slag Resistant Mechanism of Low Thermal Conductivity Microporous Corundum

The microporous corundum material was prepared using alumina micro-powder as the main raw material,alumina sol and starch as binders by a wet process,achieving the bulk density of 3. 05 g·cm~(-3),the apparent porosity of 9. 1%,the closed porosity of 12. 3%,the median pore diameter of 0. 43 μm,and the thermal conductivity of 6. 5 W·m~(-1)·K~(-1)at 800 ℃ which is41. 6% lower than that of common corundum. The slag resistance of the microporous corundum material was studied by immersion and compared with that of the common corundum aggregate, and the slag resistant mechanism of microporous corundum material was revealed. The results show that the slag resistance of the microporous corundum material is superior to that of the common corundum aggregate,the SEM and EDX show that on the reaction interface between microporous corundum and molten slag,a continuous isolation layer with a large quantity of CA_2 and CA_6columnar crystals is formed; while the common corundum aggregate reacts with the molten slag interface to form a discontinuous isolation layer of columnar crystals,through which a lot of molten slag corrodes or permeates into the aggregate. The mechanism is mainly that the microporous structure is more advantageous to nucleation and growth of CA_2 and CA_6 columnar crystals; in the reaction with the aggregate,the molten slag gets saturated and the critical solution thickness of the microporous corundum and the common corundum is 0. 16 μm and 0. 34 μm,respectively,this is caused by the smaller microporous corundum aggregate pores; and the smaller pores also increase the second phase ripening rate of microporous corundum,which is 9. 7 times of that of the common corundum.     

Preparation and Properties of Lightweight Refractories Based on Microporous Calcined Alumina

Refractories and Industrial Ceramics - Characteristics of domestic corundum insulation objects are given. The properties of corundum lightweight objects obtained from microporous calcined alumina...     

刚玉耐火材料的强化烧结

推荐在进行摩擦化学处理过程中对刚玉砂实施综合性活化,并同时加入铝酸盐助烧结剂。探索了烧结物的分解过程。计算了引入加入剂时刚玉烧结过程的活化能值。     

液体硅橡胶微孔材料的制备及性能研究

采用粒子沥滤法制备了液体硅橡胶微孔材料,研究了成孔剂的用量和微孔材料密度、孔隙率、拉伸强度及撕裂强度的关系.结果表明,随着成孔剂含量的增加,微孔材料的密度下降,孔隙率增加,拉伸强度、撕裂强度均下降;当成孔剂与硅橡胶的质量比为6:1时,可得到外观及力学性能良好的液体硅橡胶微孔材料.     

Slag Resistance Mechanism of Lightweight Microporous Corundum Aggregate

The microstructures of the reaction interfaces between slag and corundum aggregates, microporous corundum produced in the laboratory and tabular corundum were observed after slag resistance experiments, and their associated slag resistance mechanisms were investigated. A continuous isolation layer was observed around the microporous corundum, which showed a significantly better slag resistance than tabular corundum. The formation of columnar crystals of CaAl₁₂O₁₉ (CA₆) and CaAl₄O₇ (CA₂) in the isolation layer was the main reason for the difference in slag resistance. With respect to the nucleation and growth of second phase, the slag resistance mechanism of lightweight microporous corundum was explored by thermodynamic and kinetic analysis. Due to its smaller pore size, the second phase is more likely to achieve supersaturation, and large quantities of crystal nuclei are generated for microporous corundum. The critical dissolved depths of the microporous and tabular corundum in saturated slag were calculated to be 0.14 and 0.27 μm, respectively. Additionally, the small pore sizes lead to an increase in the Ostwald ripening rate of the second phase, and the Ostwald ripening rate of microporous corundum was 12 times that of the tabular corundum based on Ardell's theory.     

碎斑流纹岩制备刚玉的研究

以碎斑流纹岩为原料制备刚玉。将2.5g流纹岩、8mL水、12mL 98%浓硫酸混合于反应釜中在100℃的烘箱中反应4h,冷却,过滤;滤液用氢氧化钠溶液调节pH值至13,沉淀析出,过滤;滤液用稀硫酸调节pH值至5.2,Al(OH)3完全沉淀,离心分离;沉淀在低于100℃的温度下烘干,再在950℃下煅烧30min得到刚玉,产物经XRD确证。表明利用碎斑流纹岩制备刚玉在技术上是可行的。     

棕刚玉、铝矾土对焦宝石基喷涂料性能的影响

研究了棕刚玉和铝矾土对焦宝石基喷涂料性能的影响。研究表明．随热处理温度的提高焦宝石基喷涂料体系的线变化率表现为：单添加棕刚玉时收缩．单添加铝矾土时先收缩后膨胀．两者双添加时则先收缩后膨胀最后再收缩;双添加棕刚玉和铝矾土的体系其线变化率的变化趋势接近于单添加棕刚玉体系,而抗折强度、耐压强度变化则接近于单添加铝矾土体系;单添加棕刚玉体系在110℃、1000℃、1300℃时的抗折强度、耐压强度波动范围最小。     

蓝晶石基微孔莫来石陶瓷分离膜支撑体的制备、结构与性能研究

以蓝晶石为主要原料、γ-A12O3为辅料,采用注浆成型技术与反应烧结工艺制备出了具有针状网络结构的微孔莫来石陶瓷分离膜支撑体.系统研究了烧成温度对试样物相组成、显微结构及性能的影响,结果表明:随着烧成温度的升高,试样中莫来石的生成量增多,其形貌逐渐由针状发育成柱状,试样的性能与莫来石的生成量及形貌密切相关.针状莫来石可对基体起强韧化作用,并使气孔的有效半径微细化.在1450 ～ 1500℃,随烧成温度的升高,试样的显气孔率逐渐增大、孔径减小、强度升高.所制支撑体的体积密度为1.38～ 1.60 g,/cm3、显气孔率为46.74％ ～ 53.23％、烧后线变化率为-3.10％～2.24％、气孔孔径集中分布在1～ 20 μm、平均孔径为5.84～9.93 μm、常温耐压强度为30.1～ 37.2 MPa.     

不同类型聚氨酯微孔膜的制备与性能

分别以四种聚氨酯(PU)为基体材料,N,N-二甲基甲酰胺(DMF)为溶剂,加入氧化石墨,利用相转化法制得PU膜。利用扫描电子显微镜(SEM)观察膜的结构,再通过成膜动力学、孔隙率、吸湿率、透气性以及力学性能等测试,对共混膜的性能进行表征。结果表明:与纯PU膜相比,添加氧化石墨可使PU膜的综合性能显著提高,大孔结构大幅度减少,界面微孔数量增多,且无论是聚醚型PU膜还是聚酯型PU膜的成膜速率、孔隙率、吸湿率、透气性、拉伸强度及断裂伸长率均有提高。当聚醚型PU的软段比例较高时,PU膜的改性效果最佳。