无烟煤配比对烧结矿性能的影响

研究不同无烟煤配比对武钢烧结矿中铁酸钙的生成数量、结晶形态以及发育大小等的影响,实验室试验表明,煤粉配比为5.8%时的烧结指标较好,其铁酸钙含量最高;不同煤粉配比的烧结矿中铁酸钙均为四元复合铁酸钙,且随着煤粉配比的增加,烧结矿中铁酸钙发育变大,由细针状逐渐发育成针杆状及薄片状和板状.     

石灰活性对烧结矿中铁酸钙结晶形态的影响

研究了石灰活性对烧结矿中铁酸钙的结晶形态及数量的影响。用扫描电镜分析了不同活性度石灰的形貌,并对配加不同活性度石灰的烧结矿进行了矿相分析。结果表明：石灰活性影响烧结矿中铁酸钙的结晶形态及铁酸钙数量,活性度高的石灰有利于细针状和针状铁酸钙的形成。     

钒钛烧结矿和普通烧结矿显微力学性能对比

采用维氏压痕法对钒钛烧结矿与普通烧结矿中常见矿物的显微硬度进行测定,对比分析不同矿物的显微硬度值及压痕裂纹的萌生与扩展。研究发现,两种烧结矿中常见矿物的显微硬度从高到低依次为:钙钛矿-钛赤铁矿-铁酸钙-交织熔蚀结构-钛磁铁矿-硅酸盐;赤铁矿-交织熔蚀结构-铁酸钙-磁铁矿-硅酸盐。总体上钒钛烧结矿的显微硬度高于普通烧结矿,但部分矿物压痕裂纹多,且延伸较长,钙钛矿和钛赤铁矿断裂韧性差、易碎。烧结矿中减少板块状赤铁矿,多发展铁酸钙和交织熔蚀结构有利于提高烧结矿的显微硬度,改善烧结矿的质量。     

石灰活性对烧结矿质量的影响

研究了石灰活性对烧结矿中铁酸钙的结晶形态、烧结矿品位、强度和成品率等的影响。用扫描电镜表征了不同活性度石灰的形貌,用矿相分析、化学分析及ISO转鼓等手段表征了烧结矿。结果表明,石灰活性对烧结矿中铁酸钙的结晶形态及铁酸钙数量有影响,活性度高的石灰有利于细针状和针状铁酸钙的形成。增加石灰活性可提高烧结矿品位、烧结机垂直烧结速度和烧结矿成品率。     

碱度对钒钛烧结矿显微结构的影响

采用光学显微镜研究了碱度对钒钛烧结矿显微结构的影响.研究表明:碱度由2.1提高到2.5,烧结矿中钛磁铁矿、铁酸钙与硅酸二钙含量增加,钛赤铁矿与玻璃质含量降低;骸晶状赤铁矿与包边结构减少,显微结构由斑状向交织熔蚀结构过渡;相应的烧结矿强度增加.碱度为2.5时,铁酸钙主要以柱状、针状形态存在,钛磁铁矿主要以他形粒状形态存在,钙钛矿主要呈十字形和他形晶形态存在.     

影响钒钛烧结矿铁酸钙生成因素的研究

针对攀钢高钛型钒钛磁铁精矿烧结的特点,在实验室采用造小球焙烧的方法,进行了配碳、焙烧温度、焙烧时间等因素对钒钛烧结矿铁酸钙生成影响的试验研究.结果表明,烧结温度、气氛、碱度是影响钒钛烧结矿铁酸钙生成的最主要因素,而在化学成分中,TiO2、Al2O3对铁酸钙生成量和形态的影响较大.因此,在攀钢高钛型钒钛磁铁精矿烧结条件下,建立有利于生成细针状铁酸钙适宜的烧结工艺制度,消除TiO2、Al2O3的不利影响,是改善攀钢钒钛烧结矿品质的关键.     

碱度对石钢烧结矿矿相结构及冶金性能的影响

采用偏光显微镜研究了石钢不同碱度烧结矿的矿物组成及显微结构特征,烧结矿矿相结构与冶金性能之间的关系.研究发现:随着碱度的升高,烧结矿矿物组成简单化,粘结相含量升高,其中铁酸钙含量增加明显;显微结构均匀化,由斑状-粒状结构过渡为交织熔蚀结构,气孔率升高,出现骸晶状及菱形定向排列的赤铁矿,铁酸钙由他形晶形态过渡为针状形态....     

低钛烧结矿还原粉化机理研究

国内某厂生产的低钛烧结矿可用于2 500 m3高炉冶炼,强度指标达到普通烧结矿水平,但其低温还原粉化率仍比普通烧结矿高40%以上,还原粉化机理尚不明确。通过分段测试低钛烧结矿的还原粉化率并进行矿相分析,结果发现:低钛烧结矿中的赤铁矿-气孔结构是产生裂纹的源头,铁酸钙熔蚀结构是主要粘结相,但此结构中有许多细小裂纹,裂纹沿程存在许多赤铁矿晶粒,其还原速率较快且易形成交叉网状裂纹,使粘结相结构受到严重破坏,致使烧结矿还原粉化性能差。     

白云石和蛇纹石对烧结矿质量及显微结构的影响

白云石和蛇纹石对烧结矿质量及显微结构影响的研究结果表明:配加白云石提高烧结矿的MgO含量,烧结矿转鼓强度降低,而配加蛇纹石提高烧结矿的MgO含量时,转鼓强度提高.配加白云石后,烧结矿矿物组成主要为铁酸钙与骸晶状赤铁矿,骸晶状赤铁矿周围有大量以玻璃质物相存在的硅酸盐矿物,且有大量微细裂纹;烧结矿孔隙率大,气孔为大孔薄壁结构,所以烧结矿强度低.配加蛇纹石后,烧结矿矿物组成主要为磁铁矿和铁酸钙,钙铁橄榄石矿物增多变大,气孔为中孔厚壁结构,所以烧结矿的质量得以改善.     

WC-Co类硬质合金的低周冲击疲劳性能研究

为研究WC-Co类硬质合金的冲击疲劳断裂机制和微观组织参数对其低周冲击疲劳性能的影响,对6种牌号不同WC晶粒尺寸及Co含量的硬质合金进行了冲击疲劳试验,并用扫描电子显微镜(SEM)观察冲击疲劳断口。结果表明:当硬质合金承受冲击加载时,裂纹从粉末冶金缺陷处萌生,萌生的裂纹与孔洞相互连接形成主裂纹,主裂纹快速扩展导致材料疲劳失效。Co含量越高的硬质合金其疲劳敏感性越强,冲击疲劳寿命越短;WC晶粒尺寸越大的硬质合金其冲击疲劳寿命越长。     

不同厚度和不同部位烧结矿质量指标变化规律

通过对700、850、1 000 mm 3个料层厚度进行相应的石英杯烧结试验,研究得出随着料层厚度增加烧结成 品率逐渐增加,烧结矿转鼓指数逐渐升高,成品烧结矿的粒度组成逐渐变好,烧结固体燃耗降低;但垂直烧结速度 显著变慢,烧结利用系数降低。对3个料层厚度进行上、中、下3层的解剖研究结果表明,对于同一解剖层的烧结 矿,3个料层厚度的烧结成品率和转鼓指数大小顺序均为700 mm<850 mm<1 000 mm,同一料层厚度的烧结矿转 鼓强度指标是上层<下层<中层,平均粒度大小是上层<中层<下层。通过矿相分析得出同一料层厚度赤铁矿和 铁酸钙质量分数是上层<中层<下层,而磁铁矿质量分数是上层>中层>下层,3个料层厚度的赤铁矿和铁酸钙质 量分数依次是700 mm<850 mm<1 000 mm。     

Three-dimensional structure and micro-mechanical properties of iron ore sinter

A new analysis method based on serial sectioning and three-dimensional (3D) reconstruction was developed to characterize the mineral microstructure of iron ore sinter. Through the 3D reconstruction of two types of iron ore sinters, the morphology and distribution of minerals in three-dimensional space were analyzed, and the volume fraction of minerals in a 3D image was calculated based on their pixel points. In addition, the microhardness of minerals was measured with a Vickers hardness tester. Notably, different mineral compositions and distributions are obtained in these two sinters. The calcium ferrite in Sinter 1 is dendritic with many interconnected pores, and these grains are crisscrossed and interwoven; the calcium ferrite in Sinter 2 is strip shaped and interweaves with magnetite, silicate and columnar pores. The calculated mineral contents based on a two-dimensional region are clearly different among various layers. Quantitative analysis shows that Sinter 1 contains a greater amount of calcium ferrite and hematite, whereas Sinter 2 contains more magnetite and silicate. The microhardness of minerals from highest to lowest is hematite, calcium ferrite, magnetite and silicate. Thus, Sinter 1 has a greater tumbler strength than Sinter 2.     

磁铁矿在不同气氛下的烧结行为

采用－红外加热炉在模拟烧结温度制度的条件下，研究了磁铁矿在工业氮气及氧化气氛中的烧结行为。结果表明，在工业氮气中铁酸钙可以由磁铁矿直接生成。以该方式从烧结混合料中形成的铁酸钙含量甚微，所形成的烧结矿则由磁铁矿和硅酸盐组成。氧化气氛下烧结使赤铁矿和铁酸钙成为烧结矿的主要矿物。故磁铁矿烧结的关键在于将磁铁矿氧化，改变成矿过程而生成良好结构的烧结矿。在磁铁矿氧化不能充分发展时，配加赤铁矿是改善磁铁矿烧结     

Effect of Basicity and Alumina-Silica Ratio on Formation of Silico-Ferrite of Calcium and Aluminum

 Abstract： Baivumebo iron ore is special magnetite containing fluorine, kalium and sodium elements, and the main raw material for ironmaking of Baotou Iron and Steel (Group) Co. The effects of basicity and ratio of Al2O3 to SiO2 (A/S) on the formation of silico-ferrite of calcium and aluminium (SFCA) in Baivumebo low silica sinters were studied by means of mini-sintering, XPF-500 optical mineralogical microscope and CSS-88000 electronic universal testing machine. The results show that it is beneficial to the formation of complex calcium ferrite to enhance the basicity of Baivumebo low silica sinters. The acicular SFCA-I was increased with the enhancing basicity and reached the peak at basicity 28, then the columnar or platy SFCA formed and the bonding strength decreased. Alumina is beneficial to the formation of acicular complex calcium ferrite in Baivumebo low silica sinters. But the residual unfused Al2O3 reagent came into being when A/S was 035, while complex calcium ferrite still remained to be acicular. There is a common rule about mineralogy components affected by basicity and ratio of A/S, that is, SFCA is increasing accompanied with hematite and porosity reduced, but the content of glass phase is stable.     

烧结矿显微硬度的研究

本文介绍烧结矿显微硬度的测试方法，并对梅山烧结矿中常见矿物和显微结构的显微硬度进行了测定研究，指出在烧结矿中增加铁酸钙和赤铁矿含量具有重要意义。     

不同厚度和不同部位烧结矿质量指标变化规律

通过对700mm、850 mm、1 000 mm三个料层厚度进行相应的石英杯烧结试验,研究得出:随着料层厚度增加,烧结成品率逐渐增加,烧结矿转鼓指数升高,成品烧结矿的粒度组成逐渐变好,烧结固体燃耗降低;但垂直烧结速度显著变慢,烧结利用系数降低。对三个料层厚度进行上、中、下三层的解剖研究结果表明,对于同一解剖层的烧结矿,三个料层厚度下的烧结成品率和转鼓指数大小顺序均为700mm<850 mm<1 000 mm,同一料层厚度的烧结矿转鼓强度指标是上层<下层<中层,平均粒度大小是上层<中层<下层。通过矿相分析得出:同一料层厚度赤铁矿和铁酸钙含量上层<中层<下层,而磁铁矿含量是上层>中层>下层,三个料层厚度的赤铁矿和铁酸钙含量依次是700 mm<850 mm<1 000 mm。     

鞍钢烧结矿的矿物组成和矿相结构研究

对鞍钢二烧和四烧的烧结矿进行了冶金性能检测和分析,并采用X射线衍射、光学显微镜和扫描电镜对二烧和四烧的高碱度烧结矿进行了矿物组成、矿相结构的分析与研究。结果表明,二烧和四烧烧结矿矿物组成与结构特征的差异分别与其化学成分和冶金性能的差异相吻合,两者矿物都以赤铁矿、磁铁矿或磁赤铁矿、铁酸钙、硅酸二钙和玻璃相为主。建议四烧适当降低配碳量,使其矿相结构更趋合理。     

Preparation of Mono‐, Di‐ and Hemicalcium Ferrite Phases via Melt for Reduction Kinetics Investigations

Iron ore concentrates that are used in the iron production are usually agglomerated into sinter or pellets in order to improve their properties in the blast furnace. The main minerals in the magnetite base sinters are hematite, magnetite and Si and Al containing calcium ferrites of which the latter can exist as either monocalcium ferrite, dicalcium ferrite or hemicalcium ferrite depending on the conditions and on the material's iron/calcium‐ratio. In order to study the reduction behaviour of the sinter in the iron production, samples of monocalcium ferrite, dicalcium ferrite and hemicalcium ferrite were prepared by melting different proportions of pure calcium and iron oxides. After melting the samples were cast and cooled. Samples of hemicalcium ferrite were also heated at a certain temperature before the actual reduction experiments in order to ensure the wanted phase composition of the samples. The mineral compositions of the samples were verified using scanning electron microscopy (SEM‐EDS) as well as X‐ray diffraction (XRD). The verification showed that it was possible to produce the samples of calcium ferrites via melting. The conditions needed to reduce the calcium ferrites were estimated with thermodynamic calculations.     

Effects of Temperature and Atmosphere on Sintering Process of Iron Ores

 The relationship of time to minerals composition in sinters is investigated by mineragraphy are claritied observation and component analysis, and the effects of temperature and atmosphere on mineralization process. Results are obtained as follows. The initial melt forms below the eutectic temperature of CaO·Fe2O3 and CaO·2Fe2O3, which is complex substance containing Ca, Fe, Si and Al, rather than the binary calcium ferrite melt. Minerals composition of binding phase is related to local content of silica in melt, which is influenced by temperature. Appearance of the melt promotes the transition from hematite to magnetite, which then alters the mechanism of calcium ferrite formation. Before the formation of magnetite, the contents of Fe and Ca within the multiple calcium ferrite decrease with temperature, but in the case of magnetite presence, the content of Fe increases solely with increase of temperature and decrease of oxygen potential. Temperature and atmosphere determine minerals composition together, and bring influence on sintering process in different ways. It can be deduced that temperature affects kinetics of the mineralization process, but atmosphere just plays a role in thermodynamics.     

硼镁复合添加剂应用实践与硼镁交互作用机理

以硼酸－高镁石灰作为硼镁复合添加剂，阐述了应用硼镁复合添加剂改善烧结指标及高炉冶炼指标的工业实践；借助能谱分析（EDS）和相关理论，剖析了硼镁对烧结矿各主要矿相如磁铁矿相，铁酸钙和正硅酸钙及玻璃相的交互作用机理，应用硼镁复合添加剂的烧结矿进行冶炼焦比降低，高炉利用系数提高。