含氟烧结矿冷强度制约因素分析及改进措施

微气孔率是制约含氟烧结矿强度的关键因素，研究表明，气孔主要发育在硅酸盐粘结相中，是构成烧结矿结构的薄弱环节，裂隙易于在微气孔带上产生；ＳＦＣＡ在粘结相中成交织结构，可阻碍微气孔的产生和发展，从而降低微气孔率，增强烧结矿强度，ＳＦＣＡ同时起增强基体强度作用，ＳＦＣＡ的发育有赖于碱度的提高。     

铁矿粉烧结粘结相自身强度特性

在铁矿粉烧结过程中,熔化的矿粉在冷却过程中起着粘结周围未熔矿粉的作用,因此这一粘结相的自身强度是衡量烧结矿固结状况的重要指标之一.运用这一新概念,以八种常用的铁矿粉为对象,在固定温度、改变碱度的条件下进行了粘结相自身强度特性的实验研究,并对影响铁矿粉粘结相自身强度的因素进行了理论分析.结果表明:不同种类的铁矿粉由于其自身特性的不同,所生成的烧结粘结相的强度以及随二元碱度的变化规律有明显差异.以此可以作为烧结优化配矿的重要技术依据.     

提高包头精矿烧结矿质量的研究

本文对包头精矿烧结矿的宏观结构、微观结构及矿物组成进行了岩相及矿相研究。对其中的稀土矿物等进行电子探针分析、对烧结矿中主要胶结相矿物——枪晶石进行人工合成,测定了它的抗压强度及耐磨性。 试验研究了硅(SiO_2),氟(CaF_2)对包头精矿烧结矿强度的作用机理,测定了随着烧结矿中硅、氟含量变化与其液相性质——粘度及表面张力的关系以及它们对烧结矿结构及强度的影响。 研究表明:氟是影响烧结矿强度的主要因素,氟对烧结矿强度的破坏作用主要由于氟在烧结矿中显著降低其液相的粘度及表面张力,导致了烧结矿宏观结构疏松多孔薄壁、微观结构微孔多,其次由于氟在烧结矿形成抗压强度低、耐磨性差的枪晶石。精矿中含硅低使烧结矿胶结相量少也是降低强度的一种原因。 提高包头精矿烧结矿强度的根本途径在于选矿过程中降低精矿中含氟量到1.5％以下。把烧结矿碱度提高到2.0或配加15％高硅矿粉及3～5％清石灰、或用白云石部分代替烧结料中石灰石都有效的提高烧结矿的强度。生产碱度为2.0的烧结矿的措施已成功的应用于生产中。     

铁酸钙粘结相自身强度的研究

以烧结矿中的铁酸钙粘结相为研究对象,考察了粘结相自身的抗折、抗压强度随粘结相组成的变化规律.实验考察了不同n(CaO)∶n(Fe2O3)(摩尔比)以及MgO,SiO2和Al2O3含量对铁酸钙粘结相的抗折、抗压强度的影响规律.结果表明,n(CaO):n(Fe2O3)=1∶2时,粘结相的抗折、抗压强度最高,添加MgO使粘结相抗折、抗压强度下降,适量的SiO2(w(SiO2)<3%)能提高粘结相的抗折、抗压强度,但随Al2O3含量的增加,粘结相的抗折、抗压强度下降.     

水泥基界面剂粘结抗剪强度研究

研究了在采用不同的界面剂处理下,水泥基砂浆加固混凝土构件的界面粘结抗剪强度,并进行了加固砂浆和基层混凝土的界面处的微观结构观测分析．研究结果表明：界面剂能提高界面粘结抗剪强度．超细水泥是一种很好的界面剂原材料．通过加入膨胀剂、硅灰和高效减水剂改性后的超细水泥界面剂,有很高的粘结抗剪强度．可再分散聚合物胶粉对界面粘结抗剪强度的改善效果很明显．     

Ti(C,N)基金属陶瓷中包覆结构的研究

利用先进的微观分析手段对Ｔｉ（Ｃ,Ｎ）基金属陶瓷中Ｔｉ（Ｃ,Ｎ）的包覆结构进行了较系统的研究,研究结果表明：在硬质相颗粒的周边,Ｔｉ和Ｎｉ元素具有明显的成分梯度,Ｗ和Ｍｏ元素主要集中分布于硬质相颗粒的包覆层中,并且其分布规律相似;Ｔｉ（Ｃ,Ｎ）芯与粘结相Ｎｉ之间存在的包覆层是一种过渡相,它改善了Ｎｉ对碳化物的润湿性,使粘结相与硬质相能较好地结合．     

Ti（C,N）基金属陶瓷中包覆结构的研究

利用先进的微观分析手段对Ｔｉ（Ｃ，Ｎ）基金属陶瓷中Ｔｉ（Ｃ，Ｎ）的包覆结构进行了较系统的研究，研究结果表明；在硬质相颗粒的周边，Ｔｉ和Ｎｉ元素具有的成分梯度，Ｗ和Ｍｏ元素主要集中分布于硬质相颗粒的包覆层中，并且其分布规律相似：Ｔｉ（Ｃ，Ｎ）芯与粘结相Ｎｉ之间存在的包覆层是一种过渡相。它改善了Ｎｉ对碳化物的润湿性，使粘结相与硬质相能较好地结合。     

MgO对高碱度烧结矿强度的影响及机理

研究MgO质量分数的提高对高碱度烧结矿转鼓强度的影响规律并揭示其作用机理。结果表明:当碱度为2.0的烧结矿MgO质量分数从1.15%提高到3.5%时,转鼓强度从71.33%降低到61.13%;随着MgO质量分数的增大,液相生成温度提高,液相量减少,MgO质量分数太高将造成烧结矿液相量不足;Mg2+主要固溶在磁铁矿中,Mg2+进入磁铁矿晶格,提高磁铁矿的稳定性,不利于磁铁矿氧化,使得烧结矿中磁铁矿质量分数增大,且针状铁酸钙黏结相质量分数减少;烧结液相量较少以及具有良好强度的针状铁酸钙质量分数降低是MgO降低烧结矿强度的主要原因;白云石的成矿能力比石灰石的弱,随着白云石用量增大,熔剂与铁矿石之间的反应能力下降,因此,烧结矿转鼓强度降低。     

高配比高铝褐铁矿烧结成矿机理

以某高铝褐铁矿配比为60%~70%,配加其他含铁原料进行烧结,通过调节水碳、优化配矿等措施改善烧结产质量指标,并对烧结成矿机理进行分析。实验结果表明:Fe2O3和Al2O3分别与CaO反应时,2CaO·Fe2O3比3CaO·Al2O3及12CaO·7Al2O3更容易生成;当CaO,Al2O3,SiO2和Fe2O3四元矿物存在时,烧结过程优先生成2CaO·Al2O3·SiO2(钙铝黄长石)和4CaO·Al2O3·Fe2O3,并进一步形成SFCA,这与烧结矿SEM结果相一致;虽然烧结矿具有较多的孔洞和裂纹,但烧结矿具有良好的微观结构和冶金性能,可以满足中、小型高炉冶炼的生产要求。     

钨合金力学行为的计算机数值模拟——宏观力学性能

在微观力学行为分析的基础上，对９０Ｗ合金宏观力学性能及其与微观结构因素（粘结相力学参数）之间的关系进行了计算机数值模拟研究，结果表明：钨合金性能与粘结相力学参数密切相关，随着粘结相弹性模量增加，合金的抗拉强度增加，但延伸率当粘结相屈服强度≤８００ＭＰａ时，合金抗位强度随粘结相屈服强度增加而增大，在粘结相屈服率为８００ＭＰａ时达到最大值，随粘结相抗拉强度增加，合金抗拉强度和延伸率呈近似线性规律增加，     

烧结矿中MgO作用机理

研究了烧结矿中MgO对烧结液相生成、固结成矿的影响机理,以及不同镁质熔剂对固结强度的影响规律,并在此基础上进行了烧结杯实验研究.结果表明:随着烧结矿中MgO含量的增加,烧结液相开始形成温度上升,液相流动性和黏结相强度均降低;使用不同种类的镁质熔剂时,烧结黏结相强度有差异,在1 280℃和1 320℃下,使用蛇纹石时黏结相强度相对最高,其次是使用轻烧白云石的情况,而使用白云石时黏结相强度相对最低;在兼顾烧结矿产量、质量指标及冶金性能的前提下,烧结矿中适宜的MgO质量分数在1.2%左右,镁质熔剂则适宜选用白云石和蛇纹石组合或者单独使用轻烧白云石.     

Basic characteristics of Australian iron ore concentrate and its effects on sinter properties during the high-limonite sintering process

The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results show that the Ore-A exhibits good granulation properties, strong liquid flow capability, high bonding phase strength and crystal strength, but poor assimilability. With increasing Ore-A ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (?T) and the softening start temperature (T_10%) of the sinter exhibit the opposite behavior; the reduction degradation index (RDI_+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. With increasing Ore-A ratio, the distribution and crystallization of the minerals are improved, the main bonding phase first changes from silico-ferrite of calcium and aluminum (SFCA) to kirschsteinite, silicate, and SFCA and then transforms to 2CaO·SiO₂ and SFCA. Given the utilization of Ore-A and the improvement of the sinter properties, the Ore-A ratio in the high-limonite sintering process is suggested to be controlled at approximately 6wt%.     

Infiltration behavior of sintering liquid on nuclei ores during low-titanium ore sintering process

Sinter strength is dependent not only on the self-intensity of the residual rude and bonding phase but also on the bonding degree between them. The infiltration behavior of sintering liquid on nuclei ores influences the bonding degree, which ultimately determines the sinter strength. Infiltration tests were conducted using micro-sinter equipment. The infiltration area index of original liquid (IAO), infiltration volume index of secondary liquid (IVS), and sinter body bonding strength (SBS) were proposed to study the melt infiltration behavior. The results show that the IVS first increases and then decreases with increasing TiO₂ content in adhering fines, whereas the IAO exhibits the opposite behavior. Compared with the original liquid, the secondary liquid shows lower porosity, smaller pores, and more uniform distribution. The SBS increases first and then decreases with increasing IAO and TiO₂ content, and reaches a maximum when the IAO and TiO₂ contents are approximately 0.5 and 2.0wt%, respectively. The SBS first increases and then tends to be stable with increasing IVS. The TiO₂ content is suggested to be controlled to approximately 2.0wt% in low-titanium ore sintering.     

基于工程对象修正的统一测强曲线

当现场数据采集工作严格依照规程进行操作时,回弹法检测结果的可靠性主要取决于回弹测强曲线本身的精度。为了提高回弹测强曲线的精度,提出了一种基于工程对象修正的统一测强曲线。该方法在统一测强曲线基础上基于工程对象构造函数,并对得到的二元非线性方程组采用二分法进行迭代求解,从而得到一种基于工程对象修正的统一测强曲线。该方法原理简练、物理意义明确,是处理测强曲线的优良方法。     

Influence of basicity and temperature on bonding phase strength,microstructure, and mineralogy of high-chromium vanadium–titanium magnetite

To develop a smelting process for the comprehensive utilization of high-chromium vanadium-titanium magnetite (HCVTM), the micro-sinter test was applied to investigate the influence of basicity and temperature on the HCVTM sinters. The bonding phase strength (BS) was tested via an electronic universal testing machine. The phase transformations of the HCVTM sinters were detected via X-ray diffraction (XRD), whereas the structure and mineralogy of the HCVTM sinters under different temperatures and basicities were detected via scanning electron microscopy in combination with energy-dispersive spectroscopy (SEM–EDS). Our results demonstrate that the BS of the HCVTM sinters exhibits a slightly increasing tendency with an increase in temperature when the basicity is 2.4 and within the range of 2.8–4.0. Many cracks, small size crystals, and dependent phase structures are generated by increasing the sinter basicity. The BS is lower than 4000 N when the basicity is 2.2 and 2.8. When the temperature is in the range of 1280–1300℃, the BS exceeds 4000 N with the basicity of 2.0, 2.4, and 3.4–4.0. The pore size of the HCVTM sinters increases with the increase of the temperature. The perovskite decreases, whereas the silicate phase increases with basicity higher than 3.2. This study provides theoretical and technical foundations for the effective production of HCVTM sinters.     

添加剂对烧结矿转鼓强度的影响

针对在采用烧结矿表面喷洒CaCl2溶液进行生产时,改善了烧结矿的低温还原粉化性能,却加快了除尘系统洗涤塔内衬钢板的腐蚀速度这一现象,研究采用含硼添加剂替代部分CaCl2外喷烧结矿,能有效抑制烧结矿的低温还原粉化,很好地改善了腐蚀状况,并阐述了其对转鼓强度这一重要冶金性能的影响。     

Influence of Fabric Geometrical Structure on Bonding of the Fabric Reinforced Cement Composites

Influence of fabric geometrical parameters,including the number of filling yams per 10 cm, yarntwist and fiber type, on bonding of the fabric reinforcedcement composites is studied by fabric pull-out test andSEM microstructure analysis. The results show that thebonding strength increase with the increase of the numberof filling yams per 10 cm in the range of this study. Butthe influence of fabric count on the interfacial bonding isdual and there is a critical value. The twist of yarns hasa little effect on the bending strength and interfacialbonding behaves of nylon fabric reinforced cementcomposites. There is an optimum twist range. Withinthis range, the bonding strength increase slowly with theincrease of yarn twist. Beyond this range, it is versus.The bonding strength is strongly affected by the fabriccharacter. The bonding between the nylon fiber fabricand cement is good; that of between glass fiber fabric andcement is moderate and that of between the carbon fiberfabric and cement is poor.     

铁矿石粉矿成分对烧结强度的影响

在铁矿石烧结过程中,熔体性质决定了烧结矿粘结相的结构.采用小型试验来考察铁矿石粉矿的化学成分(SiO2,Al2O3,MgO和碱度)对烧结强度的影响.并通过化学成分对熔体的黏度和表面张力的影响来对烧结强度的变化加以解释.试验结果表明,随着粉矿中配加CaO与矿石的质量比的变化(0.08~0.15),在CaO与矿石质量比为0.12时获得最大烧结强度;而碱度R=2时获得最大的烧结强度;随着MgO含量的增加其烧结强度逐渐降低;而烧结原料中Al2O3质量分数不宜超过2.5%.     

天钢配加印度粉烧结的实验室研究

印度矿粉由于其高铁低硅,并且价格低廉,因此受到国内多个钢铁厂的青睐,为了充分发挥其优势,从不同品味的印度矿粉出发,得出其各自的烧结特点,找出不同品位印度矿粉对烧结矿的冶金性能的不同影响,并通过对烧结矿的显微结构和矿物组成分析了微观组织结构的变化规律,找出内外部条件的依存关系,有效指导了天钢烧结生产。     

高褐铁矿配比下提高烧结矿产质量指标

为了在高褐铁矿配比下提高烧结矿产质量指标,在把握烧结混匀矿特性的基础上,通过微型烧结试验和烧结杯试验,研究了高褐铁矿配比下烧结矿二元碱度、钙质熔剂种类等因素对烧结黏结相数量、强度和类型,以及烧结矿产质量指标的影响.结果表明:在高褐铁矿配比下,提高烧结矿二元碱度至2.0水平,并采取适当增加生石灰使用比例以及提高烧结抽风负压和烧结料层高度的配合措施能够改善烧结矿产质量指标.