高块矿比高炉炉料的冶金性能研究

以宝钢不锈钢事业部炼铁厂的烧结矿、球团矿、PB矿及纽曼矿为原料,采用中温还原和低温还原粉化测定方法及改进的熔滴性能测定法,研究高块矿比(15%~25%,质量分数)炉料的还原性、低温还原粉化性及熔滴性能。结果表明,块矿配比的质量分数由15%增加到25%,炉料的还原度RI降低5%,低温还原粉化率RDI-3.15升高2%,熔融区间滴落温度td与压差陡升温度ts差升高60℃左右,透气性指数的特征值S升高100 kPa·℃。     

低硅烧结矿的冶金性能及其优化配用研究

为保证低硅烧结矿高炉冶炼的稳定顺行,研究了SiO_2含量降低对烧结矿和综合炉料冶金性能的影响,并从烧结配矿、参数优化和高炉炉料结构等多方面优化了配用低硅烧结矿的综合炉料冶金性能。结果表明:SiO_2含量从5.0%降低到4.8%时,烧结矿RDI变化不大,SiO_2含量继续降低时,RDI降低的幅度变大,但可通过喷洒CaCl_2加以改善;RI不是低硅烧结生产应用的限制性环节;SiO_2含量降到4.8%的两组烧结矿软化特性最好,SiO_2含量继续降低后烧结矿熔滴区间略有变宽;通过烧结配矿和水碳、炉料结构优化后高炉综合炉料的熔滴性能明显改善。     

包钢合理炉料的软熔滴落性试验研究

利用RDL-03铁矿石高温还原软熔滴落测定系统分别测定了澳矿、球团矿和烧结矿的软熔滴落性能,并按包钢3号高炉的配料比测定了综合炉料的软熔滴落性能,通过单一炉料和综合炉料软熔滴落性的对比,研究了包钢3号高炉炉料结构的合理性.     

优化鞍钢烧结矿碱度及炉料结构的试验研究

针对目前鞍钢大型高炉炉料结构的实际,在研究了对烧结矿适宜碱度的基础上,进行了炉料结构的试验研究,结果表明,综合考虑碱度对烧结工艺和烧结矿品位及硫含量的影响,鞍钢烧结矿碱度在2.05~2.20之间较好.在维持入炉碱度不变的条件下,碱度为2.05和2.14的烧结矿和球团搭配使用时,综合炉料的软熔性能最好.再加入澳洲块矿后,软熔性能进一步得到改善,尤其当澳洲块矿比例提高到17%时,效果更佳,料柱最大压差与高温软熔时的S值相对最小.在鞍钢现有生产条件下,建议将澳矿比例提高至17%.     

遵化钢铁厂高碱度烧结矿试验研究

对不同碱度，不同钢渣量，不同焦粉量进行了多种搭配的烧结试验。选出四种较优烧结矿，并进行了冶金性能检验。把检验结果进行了对比。最后提出了优质高碱度烧结矿配比及新的炉料结构。     

高碱度烧结矿还原过程中显微结构的变化

在实验室模拟高炉气氛,进行高碱度烧结矿升温还原实验,当炉内温度达到实验温度(500,600,700,800,900,1 000,1 100℃)后立即结束实验,通过光学显微镜观察高碱度烧结矿还原过程中的显微结构,分析不同温度时高碱度烧结矿矿相的变化。结果表明:500~600℃区间内,Fe2O3开始还原为Fe3O4,低温(500℃)还原条件下,Fe3O4直接还原为星点状金属铁的雏晶;700~800℃区间内Fe3O4先还原成FexO,FexO再还原成金属铁;900℃时金属铁大量生成;1 000~1 100℃时,烧结矿内几乎是金属铁。     

改善大通钢铁厂烧结矿质量的研究

本文介绍在大通钢铁厂原料条件下,生产高碱度和高 MgO 自熔性烧结矿的优越性。并对通钢高炉如何组成合理炉料结构提出了建议。     

伊朗粉对烧结矿冶金性能的影响研究

根据重钢现有铁矿石资源配置情况,结合生产实际,针对降低原料成本增加效益的迫切要求,开展了不同比例的伊朗粉烧结实验,观察烧结矿矿相,分析了烧结矿入炉后的高温冶金性能。结果表明,重钢烧结矿中伊朗粉的最优配比为10%时,抗磨指数为5.66%,转鼓指数为69.24%,低温还原粉化率为70.24%,还原度为68.60%,软化区间为115℃,符合高炉冶炼要求。     

氟对烧结矿高温冶金性能的影响

结合饮钢生产实际，通过脱碱和浸碱实验，研究了氟对烧结矿高温冶金性能的影响。结果表明：氟不仅有自身的危害作用，不有促进钾，钠挥发的作用。当钾，钠，氟同时存在时，将严重降低结矿的软熔温度，并造成早软化，晚滴落现象。     

烧结矿／兰炭混装还原试验研究

为了降低炼铁生产成本、优化炉料结构以及充分利用低品质冶金焦资源,在实验室条件下进行兰炭用于高炉炼铁的矿焦混装初步试验研究。采用综合热分析仪研究兰炭的基础特性,并模拟高炉条件下的矿焦混装程序还原过程。结果表明,兰炭与CO2的反应性要好于焦炭,兰炭可明显降低烧结矿直接还原的起始温度并加快还原速率;在高炉还原条件下,兰炭可以降低大块焦的溶损率,提高烧结矿的还原度;增加兰炭加入量,烧结矿的还原度相应提高;在兰炭加入量相同的条件下,兰炭和烧结矿分层混装时烧结矿终点还原度较高;过多增加兰炭加入量和改变矿焦混装方式对抑制大块焦溶损率的作用较小。     

滁县精矿制取冷固球团的研究

研究了精矿粒度、水分、石灰、水泥种类和数量对生球强度和养护强度的影响,並对冷固球团的热爆裂性、还原性、低温还原粉化性和荷重软化性进行测试。根据实验结果提出滁县精矿制取冷固球团的工艺条件,指出冷固球团的热态冶金性能与焙烧球团和烧结矿相当。     

The rheological property and foam morphology of linear polypropylene and long chain branching polypropylene

The rheological behavior, thermal properties and foam morphology of linear polypropylene and long chain branching polypropylene prepared through UV irradiation reactive extrusion were studied by rheological test, melt index test, DSC and supercritical carbon dioxide foaming technology. Rheological test and melt index test confirmed that under UV irradiation and extrusion, adding photo-initiator and crosslinking agent could achieve the purpose of branching, thus improved the melt strength of polypropylene effectively. The DSC results revealed that with the introducing of long chain branching, the melting range of the polypropylene broadened and the crystallization temperature increased. Owing to the introduction of long chain branches, polypropylene exhibited higher melt strength and strain hardening behavior. Compared with linear polypropylene, the foam morphologies of long chain branching polypropylene were more uniform.     

Effect of pouring height on the solidified microstructure of AlSi7Mg alloy

The effect of different pouring heights and evenly soaking process in the liquidus and solidus range on the solidified microstructure of AlSi7Mg alloy has been studied. The results show that if the pouring temperature is 630 or 650℃ and the pouring height is 40 mm, the microstructure of the solidified melt is not homogeneous and there are many rosette-like primary α-Al grains. But if the pouring height is increased to 400 mm, the solidified microstructure becomes more homogeneous and favorable to obtain spherical primary α-Al grains in the solidified melt. With further being evenly soaked in the liquidus and solidus range for some time,the temperature difference between the melt center and the melt periphery can be controlled within ±2℃ and the primary α-Al grains will evolve into more spherical grains. The theoretical analysis indicates that the higher pouring height promotes the melt flow motion and makes the temperature field in the melt more homogeneous and restrains the large rosette primary α-Al grains. This flow motion can also promote the ripening effect and the primary α-Al grains in the melt are gradually changed into spherical grains. It can be concluded from the experiments that pouring at an appropriate superheat and from a proper height is a good new method for preparing the semisolid slurry of AlSi7Mg alloy, its process control is easy and the preparation cost is lower.     

弹塑脆性岩土材料中球形孔大应变扩张分析

在应力跌落模型基础上引进软化阈值,建立弹塑脆性模型,模拟岩土材料的脆性软化特性,采用双剪统一强度理论和不相关联流动法则,考虑软化区的大应变,对球形孔扩张问题进行求解,得出了扩张-压力的解析表达式。通过算例分析,得出软化阈值对扩张变形和塑性区范围影响显著,软化阈值越小,扩张变形和塑性区范围越大,且软化区占整个塑性区的比重越大;考虑中间主应力对屈服的影响与否,对解答也有明显的影响。     

钢包耐火材料对钢中氧含量及钢水温降的影响

利用氧势指数分析了钢包耐火材料组成、配比以及加热温度对耐火材料分解和向钢中传氧的影响,并利用热传导理论计算了钢包包衬耐火材料的绝热性能对钢水温降的影响.结果表明：随着耐火材料材质由碱性向中性和酸性的顺序变化及温度的升高,耐火材料的氧势指数增大,由耐火材料向钢中的传氧能力增加;通过使用绝热性能良好的耐火材料,可以显著降低钢水热损失,减少钢水温降.     

有机化累托石改性沥青的制备及性能研究

采用熔融插层法制备了有机化累托石(OREC)改性沥青,利用X射线衍射(XRD)表征了OREC改性沥青的微观结构,研究了OREC用量对改性沥青物理性能和粘度的影响,并通过薄膜烘箱(TFOT)和压力老化(PAV)对基质沥青和改性沥青老化性能进行了比较。结果表明:OREC可与沥青熔融插层形成剥离型纳米复合结构;OREC与沥青熔融共混后,沥青的软化点和粘度均增大;与普通沥青相比,经TFOT和PAV老化后,OREC改性沥青的软化点增量和粘度增加率显著减小,表明OREC可有效改善沥青耐老化性能。     

瓶片聚酯与纺丝级聚酯流变性能的比较

利用RH7双柱型毛细管流变仪对瓶片聚酯及纺丝级聚酯熔体的流变性能进行了对比研究.讨论剪切速率和温度对表观粘度、非牛顿指数、结构粘度指数及粘流活化能的影响.结果表明:两种熔体都属于非牛顿假塑性流体,表观粘度都随着剪切速率和温度的增加而降低;在相同的温度下,瓶片聚酯熔体的非牛顿指数比纺丝级聚酯熔体的小,而结构粘度指数则比后...     

Preparation and Properties of Phenolic Resin/Montmorillonite Intercalation Nanocomposites

1　IntroductionIntercalationcompoundingisoneoftheeffectivemethodstopreparepolymerbasecompositeswithexcellentproperties .Thepolymercanbeintercalatedintotheinor ganicmaterialswithlayeredstructures ,especiallysilicateclay ,throughintercalationcompoundingtoformthepoly merlayeredinorganicintercalationcomposites[1] .Amongmanylayeredsilicateclays ,montmorillonite (MMT)isof tenusedtopreparetheintercalationcomposites .MMTisasilicateclaymineralabundantinthenaturalworld .Itbe longsto 2∶1layeredsilica…     

Heat-transfer model on the improvement of continuous casting slab temperature

A heat transfer model on the solidification process has been established on the basis of the technical conditions of the slab caster in No.3 steel works of Wuhan Iron & Steel Corporation, and the temperature field in the solidifying slab was calculated which was verified by the measured slab surface temperature. The influences of the main operating factors including casting speed, spray cooling patterns, superheat of melt and slab size on the solidification process were analyzed and the means of enhancing the slab temperature was brought forward. Raising the casting speed to 1.3 m/min, controlling the flowrate of secondary cooling water and improving the cooling pattern at the lower segments of secondary cooling zone could improve the slab temperature effectively. And the increasing the superheat is adverse to the production of high temperature slab.     

Effect of sinter layer porosity distribution on flow and temperature fields in a sinter cooler

When sinters are filled into the sinter cooler from the sintering machine, it is commonly seen that, due to segregation ef-fects, sinters of larger size usually accumulate closer to the inner wall of the sinter cooler, whereas those of smaller size are to the outer wall. This nonuniform distribution of sinters has led to uneven cooling effect throughout the cooler. This causes the sinters leaving the cooler at a large temperature difference. This undesired temperature difference leads to the deformation and even the de-struction of the conveyors. The computational fluid dynamics (CFD) technique was used in the present work to investigate the heat and fluid flow phenomena within the sinter cooler corresponding to the different distribution of sinter layer porosity, which was highly dependent on the arrangement and orientation of sinters within the sinter cooler. It is confirmed that a high mass flow rate within the sinter layer causes a low temperature region and vice versa. The flow fields for vertically reducing porosity distribution and random distribution are almost identical indicating the relative insignificance of convective heat transfer mechanism.