烧结矿成分体系对软熔滴落性能的影响

本文通过对不同碱度和SiO2、Al2O3、MgO质量分数的烧结矿进行软熔滴落性能试验,并结合安钢及国内各大型高炉所用烧结矿技术参数和高炉实际运行参数数据进行分析总结,得出当烧结矿的SiO2质量分数为5％左右,碱度为1.95左右,CaO质量分数不超过10％,MgO质量分数不超过2％时,烧结矿的软熔滴落性能较好,滴落温度约...     

太钢适宜的高炉渣型分析

本文通过对高炉渣相图、粘度及熔化遥分析与计算，提出了改善太同炉炉遥建议；提高烧结配料中白云石的配比，使烧结矿ＭｇＯ含量达到２％～２．５５％（高炉烧结矿配经为７４％～８０％），高炉渣于元 碱度保持在１．０５～１．２０，渣中ＭｇＯ含量达到７％～８％，Ａｌ２Ｏ３控制在１４％以下。     

高炉使用高碱度烧结矿冶炼试验总结

1前言高碱度烧结矿具有良好的冶金性能，包括还原粉化率，中、高温还原性能，软烙滴落性能等。随着烧结矿碱度的提高，烧结矿的矿物结构发生了变化：强度好和还原性高的铁酸钙增加；强度差的玻璃质和还原性差的铁橄榄石减少。使其在质量上得以改善。高碱度烧结矿主要有Fe3O4、CaO．Fe2O3、2CaO·SiO2等矿物组成，其中2CaO·SiO2熔点很高（2131℃），在碱度大于1．8的烧结矿中，2CaO·SiO2增加，且因其均匀分布在CaO·Fe2O3的粘结相中使β－2CaO·SiO2比较稳定，不易转变成为γ－2CaO·SiO2。因而高碱度烧结矿具有软熔温度高、强…     

高硅原料烧结特征及对策

对于低品位、高二氧化硅原料的烧结,在烧结矿碱度CaO/SiO_2=1.6左右,FeO<14％的条件下,提高烧结矿MgO含量达5.5％以上,可提高烧结矿强度,消除风化,显著改善烧结矿质量和高炉技术经济指标。     

柳钢烧结矿的化学成分及显微结构分析

对柳钢2~#360 m~2烧结机台车截面烧结矿进行取样分析,研究上、下层烧结矿的化学成分和显微结构的差异。结果表明:在南、中、北3个位置,从上到下各层烧结矿中的FeO质量分数和碱度波动很大,FeO质量分数呈先降低再升高的趋势,碱度(CaO/SiO_2)呈逐渐下降的趋势;上层烧结矿多以赤铁矿连晶为主,铁酸钙相较少,中层烧结矿铁酸钙最多,多呈理想的针状形态,下层烧结矿中的铁酸钙生成量比中部略少;沿着料层高度方向烧结矿FeO质量分数和碱度异常偏析,导致烧结矿的液相生成量不均匀,影响了烧结矿的质量。     

关于承钢高碱度钒钛烧结矿低温还原粉化性的探讨

我国高碱度钒钛烧结矿低温还原粉化(RDI)严重。本文就如何改善高碱度烧结矿RDI进行了探讨并指出:当MgO含量提高到3.5％～4.5％时,RDI可降低约20％;用CaCl_2稀溶液浸润高碱度钒钛烧结矿,其RDI可降低28％～30％。     

日钢低碱度烧结矿生产实践

为降低铁水成本及应对块矿资源不足的问题,日钢使用低碱度烧结矿替代部分酸性炉料。通过优化配料、调整水分、烧结机工艺参数控制及设备改造,使低碱度烧结矿获得了较好的技术指标。低碱度烧结矿粘结相以硅酸盐为主,其强度及低温还原粉化性能均低于高碱度烧结矿,还原性与块矿相差不大。高炉使用低碱度烧结矿（9％～33％）未出现不适应现象,炉况稳定顺行,低碱度烧结矿使用比例为20％时,吨铁降低成本12．65元。     

烧结过程中适宜CaO/Fe_2O_3与CaO/SiO_2的选择

文中阐明Fe_2O_3—SiO_2—CaO系中CaO/Fe_2O_3与CaO/SiO_2(碱度)的关系;把该相图人为地分为四个不同碱度与CaO/Fe_2O_3的特性区,并论述了各区矿相结构特征。建议在生产中应组织低CaO/Fe_2O_3高碱度烧结料进行生产,控制烧结矿中全铁含量≥45.54%,SiO_2含量≤12.17%,CaO含量以CaO/Fe_2O_3≈0.35(或CaO/TFe≈0.5时),可作为较佳比例范围,控制CaO/Fe_2O_3(?)0.7时,可作为CaO的最大极限含量,这样可以获得高产优质低能耗的烧结矿。     

Al2O3质量分数对高碱度烧结矿软熔滴落性能影响

 对Al2O3质量分数不同的高碱度烧结矿进行了荷重软化熔滴试验,并通过对不同温度下烧结矿微观结构和矿物组成的分析,进行了Al2O3质量分数对烧结矿软熔滴落性能影响机制的探讨。试验结果表明：Al2O3质量分数增加促进了还原过程中钙铝黄长石(2CaO·Al2O3·SiO2)和浮士体共晶相(2CaO·SiO2-2CaO·Al2O3·SiO2-FeO)等低熔点富铝相的生成,导致高Al2O3烧结矿在较低温度下出现开气孔孔隙封闭,从而降低了压差陡升温度。在熔融滴落阶段,高Al2O3烧结矿中渣相的Al2O3质量分数较高。存在于金属铁颗粒之间渣相的液相线和黏度随Al2O3质量分数增加而提高,在一定程度上降低金属铁颗粒的聚合,使得烧结矿的滴落温度提高。同时,高Al2O3烧结矿具有较宽的熔滴区间,使得熔融滴落区间的透气性较差。     

高氧化镁自熔性烧结矿的生产、冶炼实践

一九七一年我厂开始生产土烧结矿。其特点是:高 SiO_2、高 MgO、低碱度(自然碱度,R_2=CaO/SiO_2≈0.3)、高强度。因碱度低,氧化亚铁高,还原性差,未能充分体现出熟料的优越性。78年四月份开始,我们试生产较高碱度、高 MgO 的烧结矿。经过几个月的生产实践,终于生产出 R_3=(CaO MgO)/SiO_2=1.6,R=1.05～1.10,MgO≈6.5%的烧结矿,我们称它为高 MgO 自熔性烧结矿,文中简称高 MgO烧结矿。随着高 MgO 烧结矿的应用,高炉各项     

ICP-AES法测定铍铜合金中Be, Ni, Ti, Co, Fe, Al, Si, Mg和Pb

通过操作条件的试验研究，用基体匹配法校正基体干扰，并选择了最佳工作条件。样品加标回收率为96％～110％，方法快速、简便、可靠，适用于铍铜合金的快速检验。     

Regional mapping panels for chromosomes 3, 4, 5, 11, 15, 17, 18, and X

The erm family of 23S rRNA adenine-N6-methyltransferases confers resistance to all macrolide-lincosamide-streptograminB (MLS) antibiotics, but not all MLS antibiotics induce synthesis of Erm methyltransferase with equal efficiency in a given organism. The induction efficiency of a test panel of MLS antibiotics was studied by using two translational attenuator-lac reporter gene fusion constructs, one based on ermSV from Streptomyces viridochromogenes NRRL 2860 and the other based on ermC from Staphylococcus aureus RN2442. Four types of responses which were correlated with the macrolide ring size were seen, as follows: group 1, both ermSV and ermC were induced by the 14-membered-ring macrolides erythromycin, lankamycin, and matromycin, as well as by the lincosamide celesticetin; group 2, neither ermSV nor ermC was induced by the 12-membered-ring macrolide methymycin or by the lincosamide lincomycin or the streptogramin type B antibiotic ostreogrycin B; group 3, ermSV was selectively induced over ermC by the 16-membered-ring macrolides carbomycin, chalcomycin, cirramycin, kitasamycin, maridomycin, and tylosin; and group 4, ermC was selectively induced over ermSV by the 14-membered-ring macrolide megalomicin. These data suggest that the leader peptide determines the specificity of induction by different classes of MLS antibiotics and that for a given attenuator, a major factor which determines whether a given macrolide induces resistance is its size.     

铂饰品中Pt, Pd, Au, Ag, Cu, Ni, Zn, Fe的测定

试验研究建立了同一试料溶液连续、同时测定铂饰品中各成分的分析方法。主体Pt以氯铂酸铵称量法及火焰原子吸收光谱(FAAS)法或电感耦合等离子发射光谱(ICP-AES)法测定滤液中残留Pt进行补差而测定。主成分Pd,Au,Ag,Cu和焊料成分Ni,Zn,Fe以FAAS法或ICP-AES法测定。其方法回收率分别为:Pt99.9%~100%;Pd99.3%~99.7%;Au99.5%~l01.5%;Ag98.0%~100%;Cu97.7%~99.3%;Zn98.0%~99.0%;Ni94.0%~105%;Fe95.0%~99.0%。实际试样分析时,各成分质量分数之和一般在99.12%~l01.2%之间,接近于100%,间接说明方法的可靠性。本法适用于Pt-Pd二元体系和Pt-Pd-Au-Cu多元复杂体系的铂饰品的破坏分析,可用于校正X荧光光谱法无损检测铂饰品的分析结果。     

稀土金属中14种非稀土杂质的ICP-MS法同时测定

本文研究了用 ICP- MS仪器同时测定稀土金属中 Mg、Al、Ti、Cr、Mo、Mn、Co、Ni、Cu、Zn、Pb、W、Nb、Ta等 14种非稀土杂质。研究了各稀土基体对被分析元素的基体效应 ,选择了相匹配的内标元素。比较了标准曲线法与标准加入法的测定结果。确定了用内标元素校正基体效应及仪器漂移 ,以标准曲线法直接测定。进行了加料回收和精密度实验 ,回收率在 94%～ 113%之间 ,RSD<10 %。被分析元素的检出限为 0 .0 1～ 0 .2 0 ng/ m L,测定下限为1～ 2 0 μg/ g。     

Increased-contrast, high-spatial-resolution, diffusion-weighted, spin-echo, echo-planar imaging

An insertable head gradient coil with a maximum gradient amplitude of 45 mT/m and a rise time of 150 musec along all three major axes was used to collect high-spatial-resolution, single-shot, spin-echo, echo-planar, diffusion-weighted magnetic resonance images with b values ranging from 0 to 2,200 sec/mm2. Improvements in spatial resolution allowed better visualization of large white matter tracts and their relation to adjacent anatomic structures. Excellent contrast and anatomic detail were revealed for most structures in the brain when a sufficient number of acquisitions were collected.     

原子荧光光谱法测定土壤中的铅、铬、镉、汞、砷、锌、铜、镍等元素研究

土壤无机污染物铅、铬、镉、汞、砷、锌、铜、镍这八大重金属,是一般土壤检测中的必检项目。金属元素在土壤中积累富集后,有可能通过雨水迁移,造成地下水,地表水污染,或者通过农作物进入食物链,进而影响食品安全和人体健康,因此,对这些元素的检测显得尤为重要。本文采用原子荧光光谱法对土壤中的金属元素进行测量,同时结合微波消解技术对样品进行处理,确保测量数据的准确性。     

Susceptibilities of non-Pseudomonas aeruginosa gram-negative nonfermentative rods to ciprofloxacin, ofloxacin, levofloxacin, D-ofloxacin, sparfloxacin, ceftazidime, piperacillin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, and imipenem

Agar dilution MICs of 10 agents against 410 non-Pseudomonas aeruginosa gram-negative nonfermentative rods were determined. MICs at which 50 and 90% of the isolates were inhibited, respectively, were as follows (in micrograms per milliliter): sparfloxacin, 0.5 and 8.0; levofloxacin, 1.0 and 8.0; ciprofloxacin, 2.0 and 32.0; ofloxacin, 2.0 and 32.0; D-ofloxacin, 32.0 and > 64.0; ceftazidime, 8.0 and 64.0; piperacillin with or without tazobactam, 16.0 and > 64.0; trimethoprim-sulfamethoxazole, 0.5 and > 64.0; imipenem, 2.0 and > 64.0. With the exception of those for Stenotrophomonas maltophilia, Burkholderia cepacia, and Alcaligenes faecalis-A. odorans, agar dilution MICs for all strains tested were within 1 dilution of inhibitory (bacteriostatic) levels as determined by time-kill methodology.