高铝硅钢渣系物性对钢包衬粘渣的影响

本文研究了高铝硅钢炉渣的熔化温度、物相组成、钢包残砖粘渣层物相结构,探讨了钢包粘渣机理.结果表明,刚玉包衬发生粘渣是因为碱度2左右的CaO-SiO2-MgO-Al2O3系炉渣的熔化温度过高、粘度过大,在浇铸温度下易析出高熔点的镁铝尖晶石.提高炉渣碱度可减少甚至避免镁铝尖晶石析出,进而显著降低高铝渣熔化温度.防止钢包粘渣的合理渣系为:碱度CaO/SiO2在3～8范围,Al2O3含量在25％～40％,MgO含量在10％以下.     

专利信息

正一种环保砖及其制备方法本发明提供一种环保砖及其制备方法,涉及砖技术领域,环保砖包括以下重量份的原料:粘土、页岩、粉煤灰、玉米秸秆、乳化沥青、陶瓷纤维、钢渣、铝矾土、纳米二氧化硅、纳米碳化硅、氧化铝、活性炭、纳米二氧化钛、凹凸棒土、硅藻土、水玻璃和水。制备方法包括以下步骤:(1)称取原料,(2)加入粉碎机,(3)混合,(4)成型,(5)干燥,(6)烧制。本发明解决了现有砖的阻燃效果一般、没有充分解决汽车尾气排放过多和装修过程中散发有毒气体的问题。     

CMS和纳米TiO2对氧化铝陶瓷烧结的影响

选用CaO-MgO-SiO2(CMS)和纳米TiO2两种添加剂及其复合来降低氧化铝陶瓷的烧结温度、改善其烧结性能.讨论了烧结助剂配比和掺量、烧结温度对氧化铝陶瓷的相对密度、抗弯强度的影响,利用扫描电子显微镜观察了氧化铝陶瓷的显微结构.研究结果发现:CMS/TiO2质量比为1/1,(CMS+TiO2)质量分数为6%,烧结温度为1450 ℃时,氧化铝陶瓷相对密度为93.07 %,晶粒细小均匀、排列紧密、平均粒径3 μm,抗弯强度达到362.87 MPa.     

高铝-尖晶石浇注料在涟钢转炉钢包上的应用

涟钢公司原有 3座 2 0ｔ氧气顶吹转炉 ,平均出钢量 2 2 .5ｔ左右 ,平均出钢温度 1685℃。钢包公称容量 2 8ｔ ,钢水全部进行底吹氩处理 ,处理时间为 3ｍｉｎ左右 ,钢水在钢包中的平均停留时间为 3 0～ 40ｍｉｎ。钢包内衬原来采用镁碳砖和铝镁碳砖综合砌筑 ,钢包的平均寿命只有     

降低钢包散热损失的研究

为了钢包保温,经过对钢包散热计算及对保温材料的研究发现,钢包衬应该采用四层材料砌筑,即在钢壳内表面涂层节能涂料,向内是10 mm的纳米绝热板,再向内是75 mm的高强纳微米隔热浇注料,再向内是工作层。渣线工作层采用低热导率的镁碳砖,熔池工作层采用刚玉-尖晶石质不烧砖。这种砌筑方式应用到120 t精炼钢包上,使得渣线处钢包壳温度约225℃,熔池钢包壳温度约200℃,包底壳温度约170℃。     

二氧化硫水溶液在修饰硫化镉粉末上的光催化反应

本文从应用意图出发,采用CdS、混Pt/CdS和镀Pt/CdS三种光催化剂,研究(1)反应温度,(2)催化剂表面含Pt量,(3)修饰方法和催化剂表面结构形貌对光催化SO_2水溶液生成H_2SO_4同时放H_2反应的活性和选择性的影响。结果表明:(1)本反应有明显温度效应,利用太阳能中约占50％的红外段辐射来提高反应温度到70℃可使活性增至7倍,但选择性下降,(2)估算了反应活化能为21kJ·mol~(-1),(3)得出60℃为反应较佳温度,(4)表面含Pt量在5％左右活性最高,(5)混Pt/CdS体系形成高分散、细颗粒分布,其催化活性比镀Pt/CdS体系为高。根据实验结果对反应机理进行了一些讨论。     

Ni-SiC纳米复合镀层耐高温氧化性能的分析

对Watts镀镍层以及添加纳米SiC的复合镀镍层的耐高温氧化性能进行了比较分析.热重和差示扫描量热试验表明,添加纳米SiC并不能明显改善镀层的耐高温氧化性能,但添加15 g/L的纳米SiC可以提高复合镀层晶面结构的热稳定性,将(111)晶面向(200)晶面转化的温度由原来的325 °C提高到365 °C.X射线衍射分析表明,添加纳米SiC会改变镀镍层的结晶取向,由原来以(200)为主,(111)为辅转变为以(111)为主,(200)为辅.经400 °C高温氧化处理后镀层的晶面结构以(200)为主,(111)为辅;经800 °C高温氧化出现氧化产物NiO和Fe3O4.     

铝—尖晶石浇注料在不锈钢钢包中的应用

1 前言 在钢铁工业用耐火材料厂家有一些中长期课题,例如:(1)提高耐火材料的有效使用效率,(2)减轻劳动强度,(3)对专门技工(筑炉工)的老龄化采取对策等。作为上述课题的一环是在各种窑炉中扩大使用不定形耐火材料。 特别是在钢包用耐火材料中,以前是以锆英石系筑炉材料为主,但是,由于①为延长钢     

新型轻质浇注料性能及其应用模拟研究

本文提出了两种新型浇注料,用于钢包永久层,分别以氧化铝空心球和页岩陶粒为骨料,通过实验测定了其热导率、体积密度、显气孔率、抗折强度等物性参数,分析了骨料粒级配比对热导率及抗折强度的影响.同时利用商用仿真软件,研究了永久层不同浇筑厚度及实验测得不同参数对于钢包壁温度场的影响,得出了如下结论:(1)两种轻质浇注料热导率随大颗粒减小呈现增大的趋势;(2)随着永久层浇筑厚度增加,钢包外壁温度降低,其降低幅度减小;(3)大颗粒减小导致的热导率等参数变化对于钢包保温效果的影响不大.     

纳米Nd2O3/TPU复合弹性体微相分离及耐热性能研究

采用超声–喷雾辅助水热法成功制备了单分散、直径40 nm的立方萤石结构的纳米Nd2O3,然后通过原位本体聚合技术制备了纳米Nd2O3/TPU(热塑性聚氨酯)复合弹性体。测试结果表明:纳米Nd2O3的引入能有效提高TPU的微相分离程度;当引入的纳米Nd2O3质量分数为0.5%时,TPU复合弹性体的玻璃化转变温度、热分解温度(硬段)及软化点分别达到–38.7、392.1、137.6℃,相比纯TPU提高了–9.0、33.7、39.1℃。最后,通过X射线光电子能谱(XPS)研究了纳米Nd2O3与TPU的相互作用机理,证实了纳米Nd2O3与TPU的氨基甲酸酯基团之间配位键的存在。     

烘烤过程钢包包壁温度场的有限元研究

利用有限元法计算了烘烤过程钢包包壁温度场 ,研究了工作层、永久层和保温层厚度对钢包包壳温度的影响     

Insulating Permanent Lining of Calcium Hexaluminate Based Castable for 300t Ladle in Baosteel

Minimizing of heat loss of liquid steel through the ladle lining led to the integration of increasing insulation function of the permanent lining and high-quality insulating layer between the permanent lining and the ladle steel shell.In this paper,a study was made on physical and thermomechanical properties and corrosion resistance of calcium hexaluminate based castables.The chemical and physical properties of CA6 based castables fabricated in this work can fulfill general requirements of the permanent lining in ladle.The permanent linings of CA6 based castables offer superb thermal insulation and corrosion resistance,compared to conventional refractory systems of 300t ladle in Baosteel.Both functions of insulation and safety work effectively in whole process of ladle operation.     

Shell powder as a novel bio-filler for thermal insulation coatings

The feasibility of employing shell powder as a novel bio-filler to prepare fluorocarbon coating is demonstrated.According to the relevant Chinese standards, the thermal and mechanical properties of the shell powder-filled fluorocarbon coating were evaluated, and compared with those filled by commercial calcium carbonate. All the shell powder-filled coatings can meet the requirements stated in the relevant standards, and with decreasing the particle size of the shell powders, the performance of the thermal insulation coating is enhanced. The coating(SC3) filled by shell powders with an average particle size of 2.81 μm possesses a better thermal insulation performance than the coating(CC) filled by commercial calcium carbonate. The coating SC3 has comparable adhesive force and washing resistance with the coating CC, and in the washing resistance test, after 2000 cycles, the coating SC3 was still able to cover totally their substrates. This work demonstrates a high value-added disposal method for the aquacultural wastes.     

Temperature-controlled conversion from Fe–Si particles to integrated Fe–Si/SiO2 core–shell structure particles during fluidised bed chemical vapour deposition

In the synthesis of ferromagnetic/SiO₂ core–shell structures, the minimum formation conditions and evolution mechanism are worth investigating. In the present study, to determine the minimum formation temperature of an integrated Fe–Si/SiO₂ core–shell structure during chemical vapour deposition in a fluidised bed, the effects of deposition temperature on the structural and magnetic performances of SiO₂ insulation coatings on Fe–Si particles were investigated. Thermodynamic calculations and differential scanning calorimetry were used to understand the thermal decomposition of C₈H₂₀O₄Si. The results of the theoretical and structural studies showed that the minimum deposition temperature of the amorphous SiO₂ insulation coating on the Fe–Si particle surface was ~880 K and that the Fe–Si/SiO₂ composite structure started to convert into an integrated Fe–Si/SiO₂ core–shell structure after the deposition temperature was raised above 920 K. The increase in the thickness of the SiO₂ insulation layer due to the increased deposition temperature was studied using X-ray diffraction and scanning electron microscope analyses. The results of X-ray photoelectron spectroscopy showed that four and five types of electronic structures existed in the SiO₂ insulation shell for silicon and oxygen, respectively, and that only 32.74 at.% of the oxygen from the Si(OSi)₃(OH) group interacted with the Fe–Si alloy surface. The results of the performance test indicated that the integrated Fe–Si/SiO₂ core–shell structure led to a substantial enhancement in the electrical resistivity of the particles and reduction in their saturation magnetisation, but hardly affected the coercive force.     

不同造孔剂对钢包永久衬用隔热浇注料的影响

钢水冶炼过程中通常利用保温隔热材料来提高钢包周转过程中的保温性能,以保证连铸钢水温度的变化适应炉外精炼过程和连铸过程的工艺需要.为了研制高气孔率、高强度的保温隔热材料,以烧结莫来石为骨料,研究了四种不同造孔剂(菱镁矿粉、聚苯乙烯球、塑料颗粒和漂珠)对浇注料显气孔率及强度的影响.实验结果表明添加菱镁矿粉作造孔剂时,与未添加或添加其他造孔剂相比,烧后试样显气孔率较低,而且当加入量超过10%时,试样强度出现显著提升;添加聚苯乙烯球、塑料颗粒或漂珠做造孔剂均能够明显提升烧后试样的显气孔率,其中添加聚苯乙烯球、塑料颗粒的试样随着造孔剂引入量的增加强度出现明显降低,而添加漂珠的试样随漂珠引入量的增加强度变化不明显;复合添加10%菱镁矿粉和5%塑料颗粒时试样气孔率为29.34%、耐压强度为42 MPa,体积密度为1.98 g·cm-3,综合指标最高,最适合于做为莫来石质钢包保温隔热浇注料的造孔剂.     

大型立式低温液体储罐的研制

从设计方案的确定、总体结构的设计以及关键技术的运用等几个方面详细介绍了大型立式低温液体储罐的设计和制造过程。该250 m3容器在-196℃的低温下工作,根据其工作性质,采用真空粉末绝热形式。储罐由一个碳钢真空外壳和一个置于其中的不锈钢内容器组成。经使用单位检验、调试与试验表明,该容器完全符合设计和使用要求。     

Grain size effect on electrical and reliability characteristics of modified fine-grained BaTiO3 ceramics for MLCCs

Fine-grained BaTiO₃-based ceramics of different grain sizes (118–462 nm) with core–shell structures were prepared by a chemical coating method, having good dielectric properties and gentle temperature stability. The grain size effect on the dielectric properties and insulation resistivity of modified fine-grained BaTiO₃ ceramics under high temperatures and electric fields were investigated. The DC bias shows a strong effect on the dielectric properties with decreasing grain size. In the finest ceramics, the absolute value of the capacitance stability factor was the smallest, indicating that the modified-BaTiO₃ ceramic capacitor with smaller grains had higher reliability under the DC bias voltage. The highly accelerated lifetime test results showed that with decreasing the grain size, samples exhibited higher insulation resistance under elevated temperatures and high voltages. Impedance analysis proved that the finer-grained ceramic with core–shell structure had higher activation energy for both grain and grain boundary, whereas the proportion of ionic conductivity was lower.     

Multifunctional Refractory-lined Vessel: Ladle Aggregate

A ladle primarily is a container used to transport molten steel from the steelmaking unit to the casting facility.The essential requirements are heat resistant,insulative and strong enough to hold molten steel up to 300 t,with a structure of multilayered refractory lining in a steel shell vessel.When a ladle is assembled with three-phase graphite electrodes,a ladle furnace forms,starting steel refining process with/without the vacuum tank degasser and RH circulating degasser,in order to meet the growing demand on high purity and higher quality steel.The working lining is under aggressive conditions that comprise the chemical reaction with molten steel,the severe corrosion of liquid slag,the disaggregation through oxidation,and the strong stress due to the impacting of the melts and gases and the effects of thermomechanical behaviors.Magnesiacarbon brick is one of the major materials,being indispensable for the slagline of a ladle furnace.Alumina-magnesiacarbon brick has played an important role to substantially increase the service life in the metal zone,from the early lining materials of high alumina and doloma bricks.The permanent lining must assume sufficient responsibility to allow finishing the process of the engaged charge in case of a failure in the working lining.The insulation layer must be as thin as possible in order to maximize the ladle’s capacity,and reduce the shell temperature for saving energy.In this issue,several integrant refractories are reviewed or investigated in order to compile a lining overview,and to contribute a prolonged service life under aggressive working conditions of the ladle furnace.     

一种短时间保温的耐高温隔热涂料

针对产品保温隔热的需要,研制一种耐热温度超过800℃,在短时间内使用的保温隔热涂料,该涂料在850℃左右的环境下使用,3 min内保温隔热温度低于250℃,适用于高温环境下短时间需要保温隔热的产品。     

二氧化硅气凝胶隔热复合材料的高温疏水改性及失效机制

SiO₂气凝胶隔热复合材料已经广泛应用于航空航天、石油化工等隔热保温领域,通过疏水改性可大幅拓展其应用场景。为了使SiO₂气凝胶隔热复合材料在更高温度仍保持良好的疏水性能,采用聚硅氧烷改性硅酸盐涂料对SiO₂气凝胶隔热复合材料进行表面刷涂疏水改性,然后研究了涂层厚度对裂纹扩张的影响以及涂层在高温下疏水性能的失效机制和刷涂改性前后复合材料的耐磨损性能。结果表明,当涂层厚度大约为13 μm时,所制备的涂层表面无裂纹,接触角可达(113±2)°,经450 ℃高温热处理1 800 s后接触角依然可以保持在105°左右,表现出良好的热稳定性,同时涂层显著提高了复合材料的耐磨损性能。