Characterization of semi-coke generated by coal-based direct reduction process of siderite

Solid wastes derived from metallurgical industries pose a significant threat to environment. The utilization and disposal of these solid wastes are the major concern in the world. Semi-coke generated in coal-based direct reduction process of iron ore is a by-product and its suitable utilization is not available so far. In order to handle it properly, the characteristics of this by-product were comprehensively investigated. A series of analysis methods were used to demonstrate its mineral compositions, petrography and physico-chemical properties. The results reveal that the semi-coke has poor washability. The fixed carbon content of semi-coke reaches 76.11% and the gross calorific value is 28.10 MJ/kg, both of which are similar to those of traditional sinter coke breeze. Also, semi-coke ash possesses lower content of SiO2, Al2O3, S and higher content of CaO and MgO, which could improve the strength of sinter ore when partially substituting for coke breeze in sintering. Semi-coke features well-development porous structure and higher reaction activity, which predicts that the sintering speed could be elevated to some extent when employing it as a partial replacement of coke breeze, so the studies further suggest that the potential adverse effect of the high reactivity on sintering process could be weakened by adequately coarsening the semi-coke's particle size.     

威钢钒钛烧结试验研究

针对威钢（四川威远钢铁公司）烧结厂使用的原料结构进行烧结杯试验,研究钒钛精矿配比和焦粉用量对烧结矿产质量的影响。结果表明,钒钛矿配比最合适的比例为15％,焦粉用量为5％。     

雅满苏铁精矿球团烧结工艺研究

试验研究了全精矿球团烧结中焦粉内配比例、焦粉粒度、烧结矿碱度的选取,另外,还进行了配加生矿粉试验.对比试验结果表明,雅满苏铁精矿全精矿球团烧结工艺明显优于普通烧结工艺.     

铝硅比对白云鄂博铁精矿烧结液相流动性的影响

运用红外线微型烧结法对白云鄂博铁精矿烧结液相流动特性进行研究。通过在烧结原料中添加纯化学试剂研究不同Al2O3与SiO2含量之比对烧结液相流动性的影响。结果表明,Al2O3含量的增加虽然促进了烧结液相量的增多,但同时提高了液相的粘度,随着铝硅比的增加烧结试样的液相流动性降低。通过对试样气孔大小的对比,揭示了烧结过程中气孔形成与烧结矿液相流动特性的关系,粘度是控制气孔形成的重要因素。气孔的形成过程伴随着液相在气孔壁上的物理化学反应,气孔直径减小使烧结试样液相流动性变差。     

攀钢西昌钢钒高炉铁水适宜硫含量分析

为了寻求炼铁、炼钢工序经济适宜的铁水硫含量,通过对生产数据的统计,分析了攀钢西昌钢钒1号高炉铁水硫含量与技术经济指标的关系,得到了攀钢西昌钢钒高炉铁水钛含量与铁水硫含量及焦比的回归公式;并依据高炉冶炼过程中实际的矿焦比与铁水钛含量的经验数据,计算分析了不同铁水硫含量与炼铁的原、燃料成本的关系,综合考虑炼钢脱硫成本的变化,得出当前硫负荷条件下铁水适宜的硫含量（质量分数）应控制在0.085％左右．     

内配碳对双层球团还原膨胀率的影响

分别以磁铁矿粉和赤铁矿粉为原料制备双层结构的球团,并在球团内层配加焦粉,研究不同矿种及内层不同的配碳量对球团还原膨胀性能的影响。结果表明:在相同造球工艺和焙烧制度条件下,分别以磁铁矿粉和赤铁矿粉为原料制备的内层配碳双层球团的还原膨胀性能存在明显差异;以磁铁矿粉为原料的双层球团随着内层配碳量的增加,球团的还原膨胀率(RSI)先降低后升高,配碳量1.0%(质量分数,下同)时最低,RSI为7.98%;以赤铁矿粉为原料的双层球团随着内层配碳量的增加,还原膨胀率呈降低趋势,配碳量为1.5%时最低,RSI为9.52%。从球团的显微矿相结构看出:以磁铁矿粉为原料的双层球团内层配碳量超过1.0%,球团内出现磁铁矿晶体;以赤铁矿粉为原料的双层球团内层配碳量超过1.5%,球团内出现磁铁矿晶体,球团强度开始下降且还原膨胀率升高。     

冲击载荷下磁铁矿石破碎的能量耗散特性

针对金属矿山企业破碎磁铁矿石时,存在着耗能巨大且能量利用率较低的工程问题. 利用分离式Hopkinson压杆装置和高速摄影技术,首先,研究了磁铁矿石在冲击载荷下的能量运移转化规律及其机理;其次,采用标准方孔砂石筛与GZS-1高频振筛仪,分析了不同耗散能下磁铁矿石破碎块度的分布规律、平均块度的变化情况、以及矿石冲击破碎模式的转变过程;然后,分析了随应变率提高,矿石能量耗散率与破碎程度的相关性问题;最后,结合影响矿石块度分布的基本因素,推导出了磁铁矿石平均块度的预测模型表达式. 结果表明:随入射能提高,矿石波阻抗的降低,改变了矿石与压杆间的透射系数与反射系数,影响着各能量在入射能中的占比分布,即能量耗散率和能量反射率增大,而能量透射率却减小;耗散能越高,磁铁矿石的破碎程度越重,当耗散能由14.79 J提高到121.18 J时,矿石破碎块度的主要分布区域由粗粒端（26.5 mm,37.5 mm）向细粒端（4 mm,16 mm）移动;耗散能与平均块度（d_s）呈减对数关系,d_s降低了56.04%;d_s存在着一个临界值,当d_s大于该值时,矿石能量耗散率和破碎程度呈正相关;反之,两者呈负相关;在该值处,磁铁矿石可实现最优破碎. 研究成果对于磁铁矿石破碎工序中的能耗控制具有一定参考价值.     

Effect of coal levels during direct reduction roasting of high phosphorus oolitic hematite ore in a tunnel kiln

The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorization agent were mixed and the mixture was then roasted in a tunnel kiln. The roasted products were treated by two stages of grinding followed by magnetic separation. XRD and SEM–EDS examination of the products was used to analyze differences in the roasted products. The results show that coal is one of the most important factors affecting the direct reduction roasting process. When the inner coal levels increased from 0% to 15% the iron grade decreased linearly from 94.94% to 88.81% and the iron recovery increased from 55.94% to 92.94%. At the same time the phosphorus content increased from 0.045% to 0.231%. Increasing the inner coal levels also caused more hematite to be reduced to metallic iron but the oolitic structure of the roasted product was preserved in the presence of high coal loading. The phase of the phosphorus in raw ore was not changed after direct reduction roasting. The effect of coal on the phosphorus content in the H-concentrate arises from changes in the difficulty of mechanically liberating the metallic iron from the phosphorus bearing minerals.     

细粒嵌布贫铜镍矿的特征及其对选矿的影响

为了探明广西融水某铜镍矿矿石的工艺矿物学性质,采用光谱半定量分析、化学多元素分析、物相分析等方法,对矿石的物质组成、铜镍在矿石中的赋存形式及黄铜矿、镍黄铁矿的嵌布特性等进行了系统研究.结果表明：该铜镍矿石铜的品位为0.83％,硫化铜中的铜占96.02％,主要赋存于黄铜矿中;镍的品位为0.52％,硫化镍中的镍占73.08％,主要赋存于镍黄铁矿中,但氧化镍和硅酸镍的存在会影响到镍的回收率,其中氧化镍采用常规的浮选药剂是较难回收的,而硅酸镍是不能回收的,所以实际上25.00％的镍是不能回收的.矿石的结构较复杂,矿石中的镍黄铁矿、黄铜矿的粒度以细粒为主,且镍黄铁矿、黄铜矿、磁黄铁矿、黄铁矿之间共生关系密切,多数以非自形晶结构为主,接触边界不规则,给硫化矿物之间的分离带来困难,从而影响铜镍精矿品位.     

NOx reduction in the sintering process

A new process, NOx reduction with recycling flue gas and modifying coke breeze, was proposed. The effects of modified coke breeze and recycled flue gas on NOx reduction were investigated by sinter pot tests. The results show that the NOx reduction rate is over 10wt% in the sintering of modified coke breeze, the effects of the additives on NOx reduction are: CeO2CaOK2CO3.The NOx reduction rate increases with the amount of recycled flue gas, and is 22.35wt% in the sintering with recycling 30vo1% of the flue gas. When 30vo1% of the flue gas is recycled into the sintering of CeO2, CaO, and K2CO3 modified coke breeze, the NOx reduc-tion rates are 36.10wt%, 32.56wt%, and 32.17wt%, respectively.     

SiO_2对烧结矿矿相组成的影响

采用化学试剂配成不同SiO2含量的原料,高温烧结,制成试样,对其进行观察,分析SiO2成份对烧结矿矿相组成的影响。实验结果表明,随着SiO2含量减少,碱度增加,铁酸钙和氧化亚铁的含量也随着增加,磁铁矿含量相应减少;烧结样的气孔率变小,气孔趋于不均匀分布。当SiO2的含量很高时,相应出现硅酸盐相。     

Effect of the catalyzing combustion of coke breeze on the energy saving in sinter process

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Effect of sintering atmosphere on microstructure and properties of TiC based cermets

The effect of the sintering atmospheres （vacuum, N2, Ar） on the microstructures and properties of the TiC based cermets was studied using XRD, SEM/BSE and energy dispersive spectrometer. Compared with the alloy sintered in vacuum, the carbon content of the specimen sintered in N2 and Ar is lower by 0.5%; and the nitrogen content is higher by 0.3% when sintered in nitrogen. The central part of the ring structure may be carbide with either a high W or Ti content. The ring structures are （Ti, W, Ta, Mo, Co, Ni）C solid solutions with different metallic elements and distributions. The composition of the binder phase is （Co, Ni） solid solution with different Ti, W, Ta, Mo, C contents. The structures are uniform for the cermets sintered in vacuum and the properties are the best. When sintered in Ar or N2, the O2 and N2 in the atmosphere take part in the sintering reaction to break the carbon balance in the cermets to form a shell structure and defects, which results in poor density, microhardness （HV） and transverse rupture strength （TRS）.     

Numerical Modeling of NO Formation during Packed-bed Combustion of Coke Granules

A comprehensive kinetic model of NO formation during coke combustion in packed-bed in presence of noncombustible particles was developed. The detailed homogeneous gas-phase chemistry (including 102 chemical reactions), heterogeneous gas-solid chemistry (including 11 reactions) of coke combustion and NO formation, and the heat and mass transfer were taken into account in the present model. The governing equations which are strongly coupled, non-linear and unsteady with 26 unknowns in total, were dispersed into differential equations with the finite differential method. Meanwhile, all the differential equations were numerically solved to give the time-histories and space-distributions oftemperatures of the bed and gas phase as well as the concentrations of all the gaseous species. By comparison, the experimental data were explained well by the calculated results. Based on the kinetic and mathematical model, the effects of O2 content of inlet gas, the initial chemical analysis of coke, bed-temperature and local reductive atmosphere (CO/O2) on NO formation during packed-bed coke combustion were numerically discussed. It was found that coke samples with a higher initial content of [N] and volatile matters, combusted under a suitable O2-containing atmosphere produced less NO emission. The reactions between CO and NO, catalyzed by high temperature surface of coke particles may be responsible for efficient reduction of NO.     

烧结温度对氧化物法制备Ni-Zn铁氧体的介电性能影响

采用氧化物法制备了Ni0.5Zn0.5Fe2 O4铁氧体;样品的相组成成分、微结构和介电性能分别采用X射线衍射仪(XRD)、扫描电镜(SEM)、阻抗分析仪进行表征,讨论了经不同温度预烧和烧结后的样品微结构和介电性能.结果表明:950℃和1 000℃预烧的样品有Fe2 O3第2相产生,随着烧结温度的升高,微晶尺寸和密度逐渐增大;介电常数呈现先减小后增大的趋势,在1 200℃时有最小值;1 300℃下烧结样品的介电损耗角正切有峰值出现,表现出了异常的介电行为.     

Effect of Moisture on Combustion Characteristics of High-Moisture-Content Coal Slime

水分对高水分煤泥燃烧特性的影响

王永堂1,王辉2,刘松霖2,杨海瑞3,吴江全2

（1. 哈电集团中央研究院,哈尔滨150028;2. 哈尔滨工业大学 能源科学与工程学院,哈尔滨 150001;3清华大学 能源与动力工程系,北京 100084）

摘要：

本文研究了煤泥中水分对其燃烧特性及孔隙结构变化的影响。在实验室规模的流化床反应器上获得了水分对床温变化、燃烧效率及NOx与SO2排放的作用规律,揭示了最低床温会随水分的增加而降低,而最高床温的变化与此不同。而且,随着水分的增加,观测到的烟气黑度增加并生成更多CO,从而导致煤泥燃烧效率降低。然而,水分的存在对降低NOx和SO2有利,随着水分增加,NOx和SO2的生成量趋于降低。水分对煤泥燃烧过程的影响主要体现在燃烧初期水分剧烈蒸发形成了较大的水蒸气通道,有利于水分的蒸发和散失,也有利于水分与煤燃烧产物的反应,例如CO的生成,NOx与SO2的降低等。由水蒸气作用形成的大孔会随着水分减少而减少,纳米级孔主要是蒸发结束后挥发分燃烧与焦炭形成过程所致,并会随着水分的减少而增加。

关键词：水分;燃烧特性;孔隙结构;煤泥

     

Influence of hydrogen-enriched atmosphere under coke oven gas injection on reduction swelling behaviors of oxidized pellet

It is of great importance to elucidate reduction swelling behaviors and reaction mechanism of oxidized pellet in hydrogen-enriched atmosphere under coke oven gas injection. In this work, the effects of hydrogen concentration in N_2-CO-H_2 atmosphere with unchanged CO content on reduction swelling behaviors of oxidized pellet at 1173 K were studied, to clarify the mechanism of hydrogen-enriched reduction and exclude the influences of CO. Then, the reduction swelling behaviors of oxidized pellet at 1173 K in actual atmosphere under coke oven gas(COG) injection, got from the simulation results of multi-fluid blast furnace model, were investigated. The results show that with the concentration of hydrogen increasing in N_2-CO-H_2 gas from 2% to 18%, the reduction swelling index of pellet decreases from 10.12% to 5.57% while the reduction ratio of pellet increases obviously from 39.85% to 69.58%. In addition, with COG injection rate increasing from 0 to 152.34 m~3/t, the reduction swelling index of pellet decreases slightly from 10.71% to 9.54% while the reduction ratio of pellet is increased from 31.57% to 36.39%. The microstructures of pellet are transformed from the platy structure to the flocculent structure.     

磷灰石型La（9.33）（SiO4）6O2电解质的烧结及性能

在燃烧法制得的磷灰石型LSO电解质纳米粉体基础上,研究了预处理、成型压力、烧结温度和保温时间对LSO烧结体致密度的影响.烧结实验结果表明：球磨预处理和合适的成型压力,可以有效消除颗粒间的团聚、降低烧结温度和提高致密度;最佳成型压力为225 MPa;最佳烧结温度为1 400℃下保温3 h,烧结体的致密度高达96%.运用交流阻抗谱法研究了LSO烧结体的电性能,结果表明：烧结体随温度的升高,晶界电阻逐渐减小,晶粒电阻逐渐占据主导;烧结体电导率与温度的关系符合Arrhenius经验公式,700℃时离子电导率达到4.38×10^-3s/cm.     

氧化锆流延基片的烧结温度及其性能研究

比较了3种不同的烧结温度对氧化锆流延基片性能的影响。结果表明,随着烧结温度的升高,基片的收缩率和相对密度增加、硬度增加、气孔率减小、晶粒和气孔的平均尺寸均有所增加。在1500℃保温3h可以获得较高的致密度（相对密度97．8％）和合适的晶粒尺寸,试样在1073K时离子电导率为1．187×10^-2S·cm^-1,烧结体物相主要为四方相。     

扬子板块西缘攀西地区白草矿区黄铁矿标型元素特征及其指示意义

黄铁矿是重要的金属硫化物矿物,在多种矿床中均有产出,其标型特征对矿床成因、矿体空间分布等具有重要的指示意义。以扬子板块西缘攀西地区白草矿区黄铁矿为研究对象,利用矿相学、电子探针等分析方法来对比研究浸染状、致密块状、斑杂状、网脉状矿石中黄铁矿的标型元素特征。结果表明:白草矿区黄铁矿Fe、S平均含量(质量分数,下同)分别为46.030%、52.815%,介于岩浆成因与热液成因之间,根据矿石特征,黄铁矿以岩浆成因为主,并有少量热液作用参与; 将白草矿区黄铁矿δFe-δS特征与金川等典型铜镍硫化物矿床黄铁矿对比,表明白草矿区黄铁矿为典型的岩浆熔离型; 由于存在钒钛磁铁矿,Co/Ni值多小于5,说明钒钛磁铁矿与硫化物存在共生关系; 岩浆内生成因黄铁矿S/Se值小于15 000,白草矿区黄铁矿S/Se值为812～10 466,显示白草矿区黄铁矿为岩浆内生成因; Se/Te值随温度降低而升高,显示上述4类矿石黄铁矿结晶顺序为浸染状矿石→致密块状矿石→斑杂状矿石→网脉状矿石; 原始地幔标准化主量、微量元素蛛网图显示白草矿区黄铁矿兼具岩浆成因与热液成因。综上所述,攀西地区白草矿区黄铁矿成因主要以岩浆熔离作用为主,并含有少量热液作用。