Influence of gangue existing states in iron ores on the formation and flow of liquid phase during sintering

Gangue existing states largely affect the high-temperature characteristics of iron ores. Using a micro-sintering method and scan- ning electron microscopy, the effects of gangue content, gangue type, and gangue size on the assimilation characteristics and fluidity of liquid phase of five different iron ores were analyzed in this study. Next, the mechanism based on the reaction between gangues and sintering mate- dais was unraveled. The results show that, as the SiO2 levels increase in the iron ores, the lowest assimilation temperature （LAT） decreases, whereas the index of fluidity of liquid phase （IFL） increases. Below 1.5wt%, Al2O3 benefits the assimilation reaction, but higher concentra- tions proved detrimental. Larger quartz particles increase the SiO2 levels at the local reaction interface between the iron ore and CaO, thereby reducing the LAT. Quartz-gibbsite is more conductive to assimilation than kaolin. Quartz-gibbsite and kaolin gangues encourage the forma- tion of liquid-phase low-Al2O3-SFCA with high IFL and high-Al2O3-SFCA with low IFL, respectively.

Thermodynamic Behavior of Manganese and Phosphorus between Liquid Iron and CaO-MgO-SiO_2-Al_2O_3-Fe_tO-MnO-P_2O_5 Slags

The thermodynamic behavior of manganese and phosphorus between liquid iron and CaO-MgO-SiO2-Al2O3-FetO-MnO-P2O5 ladle slag system was addressed by investigating the thermodynamic equilibria between liquid iron containing Mn and P and the ladle slag at 1873 K. The Mn distribution ratio L-Mn increases with increasing FetO content and decreasing the basicity ((%CaO + %MgO)/(%SiO2 + %Al2O3 + %P2O5)) in slag, while the P distribution ratio Lp seems to be increased as FetO content and the basicity increases. The values of L-Mn and L-p decrease by the addition of Al2O3 into slag. The expression of the dependence of L-Mn and L-p on the basicity and FetO content in slag was obtained.

Efficiency of Iron Supported on Porous Material (Prepared from Peanut Shell) for Liquid Phase Aerobic Oxidation of Alcohols

Catalytic activity and selectivity of prepared catalysts (Fe2O3/ and Fe2O3/AC(KOH)) were investigated for liquid phase aerobic oxidation of primary and secondary alcohols, in a batch reactor, using solvent free condition and/or eco-friendly solvents. The catalysts were characterized by SEM, EDX, XRD, FTIR, TGA/DTA, and surface area and pore size analysis. Experimental data revealed that Fe2O3/AC(KOH) was an efficient catalyst for the oxidation (dehydrogenation) of alcohol while was found to show catalytic activity for both dehydration and dehydrogenation of alcohols. The catalysts were recycled by simple filtration, and used several times without any loss of catalytic activity.

STUDY ON THE VARIATION MECHANISM OF CARBON CONTENT OF LIQUID IRON IN MELTING GASIFIER

This paper studied the changing principles of carbon content in direct reduction iron (DRI) and liquid iron in the COREX melting gasifier. Under the normal working conditions of experimental equipment, liquid nitrogen was poured into the melting gasifier from its tuyere to cool down quickly. And then seven cross sections were made to study the carburization reaction and its characteristics of the solid iron and the liquid iron, and also the reaction of carbon between the slag and the metal. According to the results, the influences of the thickness of the semi-coke layer and the temperature on the carbon content of liquid iron in the COREX melting gasifier were confirmed.

Dissolution Equilibrium of Calcium Vapor in Liquid Iron

The dissolution equilibrium of calcium vapor in liquid iron was carried out at 1873 K in a two-temperature zone furnace by using vapor pressure method.A sealed Mo reaction chamber and a self-made CaO crucible were used in this experiment.The thermodynamic parameters obtained are as follows for reaction Ca(g) =[Ca]\nK = 4.27-15040/T△G^0 = 125000-35.5T J/mol The relation between dissolved amount of calcium in liquid iron(1873K) and calcium vapor pressure is expressed as[%Ca]= 0.028 pc.

Dissolution Equilibrium of Bismuth Vapor in Liquid Iron and the Interaction Effect of Third Element

The dissolution equilibrium of Bi vapor in liquid iron and the interaction effect of third element were conducted in a sealed Mo reaction chamber by vapor pressure method. The relationship between the standard solution Gibbs free energy of Bi in liquid iron and temperature obtained can be expressed. The interaction coefficients of third elements on Bismuth in liquid iron at 1 873 K can be deduced.

Effect of operating conditions and potassium content on Fischer-Tropsch liquid products produced by potassium-promoted iron catalysts

The dependencies of Fischer-Tropsch synthesis liquid hydrocarbon product distribution on operating pressure and temperature have been studied over three potassium-promoted iron catalysts with increasing potassium molar content. The study followed an experimental planning and the results were analyzed based on surface response methodology. The effects of different operating conditions and potassium contents on the liquid product distribution were compared based on number average carbon number and dispersion. Results showed that high pressures （25 to 30 arm） favored the production of waxes that could be converted into liquid fuels through hydrocracking, while greater direct selectivity towards diesel was favored by low pressure （20 arm） using catalysts with low potassium to iron molar ratios. The liquid product distribution produced using an iron catalyst with high potassium content presented higher number-average number of carbons when compared to the distribution obtained using an iron catalyst with low potassium content.

Iron Fibers Arrays Prepared by Electrodepositing in Reverse Liquid Crystalline

Ordered iron fiber arrays were electrodeposited on the surface of zinc foils using ＂FeSO4 solution-sodium caprylate-Decanol＂ 3-component reverse hexagonal liquid crystal as soft templates. The structure of the soft templates and the synthesized iron ,fibers were characterized by polarizing microscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy dispersive X-ray microanalysis etc. The experimental results shou that the synthesized iron fibers with a crystal phase grew up in the form of fiber clusters of about 200 nm along the direction perpendicular to the cathode surface. Each cluster was composed of several tens of fibers. The fibers had almost the same length of more than 10μm with a diameter of about 50 nm.

Solubility of Ba in Liquid Iron and Interaction Effect of the Third Elements

Experiments were carried out at 1873 K in a double-temperature zone furnace using vapor pressure method. The equilibriumtests of bedum vapor with liquid iron were conducted in CaO crucibles sealed in a Mo chamber. As a result, the experiments obtainedthe relation between the dissolved content of Ba in liquid iron and the vapor pressure of Ba and the standard Gibbs energies for the re-actions Ba(g)=[Ba] and Ba(l)=[Ba].

Liquid structure of pure iron by X-ray diffraction

The liquid structure of pure iron at 1540, 1560 and 1580 deg C was studied byX-ray diffraction. The results show that near the melting point there is a medium-range orderstructure that fades away with the increasing temperature. The average nearest distance of atoms isalmost independent of the melts temperature, but the average coordination number, the atom clustersize and the atom number in an atom cluster all decrease with the increasing temperature of themelt. Near the melting point there are a lot of atom clusters in the pure iron melt. The atomcluster of pure iron has the body-centered cubic lattices, which are kept from the solid state. Andthe body-centered cubic lattices connect into network by occupying a same edge. The atoms in thesurrounding of the atom clusters are arranged disorderly.

Layer Structure Analysis of Low-Carbon Steel Containing Rare Earth by High-Temperature Carburizing of Liquid Cast-Iron

The layer structure of low-carbon steel containing RE by high-temperature (T>1200 ℃) carburizing of liquid cast-iron was studied and the diffusion activation energy of carbon was calculated by metallographic microscpe, chemical analysis etc. The result shows that the technology of carburizing in liquid cast-iron can expedite caburization distinctly and changes the carburizing layer structure. The carburizing rate is 60～80 times of that of the traditional technology, and there is about 43% decrease in the activation energy compared with gas-carburization. In outer structure layer, cementite is formed simultaneously both on the crystal boundary reticularly and inside the crystal grains stripedly. In inner carburizing layer, there is undissolved blocky ferrite in reticular cementite. Besides, rare earth element can expedite carburization process.

有机酸-硫化零价铁处理高浓度含铬废液及铬铁资源化的研究

针对含铬废液净化污泥杂质含量高、铬含量低导致铬回收难的问题,以有机酸-硫化零价铁为铬废液净化剂,在高效去除废液中铬的同时,可净化污泥并直接制备铬铁合金。通过考察零价铁硫化程度、初始废液pH值、不同有机酸摩尔比、硫化零价铁用量等影响因素对废液铬净化与污泥铬富集的影响,探索铬污泥直接制备铬铁合金工艺。研究显示,采用有机酸-硫化零价铁协同处理后,废液总铬质量浓度可由5 324.1 mg/L降低至4.30 mg/L,与未改性零价铁技术相比,铬净化去除率由65.45%提高至99.92%。净化污泥铬铁元素平均质量分数大于46%,在1 500℃,氩气保护气氛下,添加质量分数为30%碳粉即可成功制备铬铁合金。铬铁合金产物中铬铁元素分布均匀,杂质含量较少。XRD分析显示,硫化零价铁的掺入质量增大可降低合金产品中杂相的生成。研究方法为冶金、化工等行业含铬废液的高效净化及资源化处理提供了一条新路径。

高铁赤泥钙化还原过程液相生成抑制机理

高铁赤泥中赋存大量铁资源难以回收利用,钙化还原—磨选方法可实现赤泥中铁、铝组分的高效分离。针对高铁赤泥钙化还原过程中易形成液相,导致物料熔化和设备黏结的问题,本文提出分段式钙化还原—磨选技术路线,研究不同温度制度下,高铁赤泥钙化还原产物的形态、金属化率、微观结构、金属铁晶粒的生长规律和相关磨选指标。结果表明:采用分段钙化还原焙烧,可在低温阶段完成铁氧化物还原至金属铁和钙铝化合物形成的反应过程,在高温阶段完成金属铁颗粒的聚集长大过程,将低熔点物形成和高温焙烧分离进行,抑制液相生成。采用第一段1 125℃焙烧30 min、第二段1 200℃焙烧40 min的分段焙烧制度,还原过程无明显液相生成,金属铁颗粒的平均粒度达到21.52μm。还原产物经磨选后,所获得的还原铁粉TFe质量分数和Fe回收率分别达到92.84%和78.68%。本文研究成果可为高铁赤泥的资源化利用提供理论依据。

孕康口服液对缺铁性贫血孕鼠产后恢复及子代质量的影响

目的 探究孕康口服液对缺铁性贫血(IDA)孕鼠产后恢复及子代质量的影响。方法 采用饲喂缺铁饲料联合放血法建立缺铁性贫血孕鼠模型,造模成功后,在妊娠第7天同期灌胃给予琥珀酸亚铁片(52 mg/kg)及孕康口服液(9、6、4 mL/kg),每天1次,直至产后6周。结束后,检测小鼠相关体征指标(自主活动、抓力、背温、爪色)、脏器系数(心脏、脾、胸腺系数)、外周血指标(RBC、HGB、HCT、MCH、MCHC)、铁代谢相关血清因子指标(EPO、FEP、SF、sTfR、TFR1),免疫组化法检测肝组织FPN、Tf蛋白表达,免疫荧光法检测肝组织TFR1、Hepcidin蛋白表达,RT-qPCR检测肝组织Hepcidin、FPN、Tf、TFR1 mRNA表达,测定子代相关情况(存活率、自主活动、抓力、爪色、心脏系数、脾脏系数、体长、外周血象指标)。结果 孕康口服液可提高IDA孕鼠产后的自主活动次数、抓力、背温、爪色(P<0.05,P<0.01),降低心脏和脾脏系数(P<0.01),提高全血RBC、HGB、HCT、MCH、MCHC水平(P<0.05,P<0.01),降低血清EPO、FEP、TFR1、sTfR水平(P<0.05,P<0.01),升高SF水平(P<0.05,P<0.01),提高肝组织Hepcidin、FPN mRNA及蛋白表达(P<0.05,P<0.01),降低Tf、TFR1 mRNA及蛋白表达(P<0.05,P<0.01)。与模型组比较,孕康口服液各剂量组子代存活率、自主活动次数、抓力提高(P<0.05,P<0.01),心脏系数、脾脏系数降低(P<0.05,P<0.01),体长增加(P<0.05,P<0.01),全血RBC、HGB、HCT水平升高(P<0.01)。结论 孕康口服液可改善IDA孕鼠的贫血状况,促进其产后恢复,并提高子代质量。

不同w(SiO_(2))铁精矿高温烧结性能研究与优化配矿

本文以新钢4种不同w(SiO_(2))的铁精矿为研究对象,深入探讨同化性能、液相流动性能、烧结体固结强度和铁酸钙生成特性等高温烧结性能,并以此为基础,结合现场生产方案进行优化配矿烧结试验。结果表明:在固定碱度为1.95的条件下,随着铁精矿中w(SiO_(2))提高,液相生成温度降低,液相生成量显著增加,液相流动性改善,但w(SiO_(2))过高会对同化性能和烧结体固结强度产生负面影响;合理调控w(SiO_(2))是优化烧结成矿过程的液相特性以及改善烧结矿质量的关键;通过优化精矿配比使含铁原料的w(SiO_(2))分数由3.90%提高至3.99%,烧结机利用系数提高0.25 t/(m^(2)·h),烧结矿成品率和转鼓强度分别提高5.91%和8.12%,固体燃料消耗则降低5.59 kg/t,烧结矿指标显著改善。

LFP电池热失控液氮冷却惰化理论分析方法研究

传统的商用灭火剂扑救锂离子电池热失控火灾和抑制复燃的效果不佳,液氮作为一种高效的灭火剂,其冷却抑制锂离子电池热失控的效果得到了很多研究机构试验验证,但目前针对液氮灭火用量和灭火效能尚缺乏理论分析方法。笔者通过对液氮灭火机理的理论分析,研究确定了液氮冷却和惰化理论分析计算方法。方法中通过试验和理论分析确定热失控放热热量、液氮吸热热量、液氮惰化用量等,并通过实尺试验验证方法的有效性。以280 Ah磷酸铁锂电池热失控为例,依据理论分析方法,计算得到了惰化抑爆和冷却的最低液氮用量,在有效容积为38.88 m3的爆炸试验箱体内,施加了83.39 kg液氮后,24 h间隔点火48次,均未出现燃爆现象。通过实际案例验证理论分析方法的有效性和合理性,提出的理论分析方法为液氮灭火抑爆的设计和有效性分析提供评价手段和方法,进一步增强磷酸铁锂电池舱式储能系统的安全性。

铁矿粉种类和成分对其烧结基础特性的影响

铁矿粉的同化性能、黏结相强度与液相流动性等基础特性是烧结优化配矿的重要基础。对BX、YLJ和NFJ等多种铁矿粉进行基础特性检测,并将2种及2种以上铁矿粉混合进行拓展研究。分析铁矿粉基础性能的主要影响因素和三大矿种的基础性能特征,提出基于同化性能、液相流动性的互补配矿思路,为增加性价比高的缺陷矿用量、提高生产质量、降低配矿成本提供理论指导。

三钢铁矿石高温基础特性评价与研究

为保证烧结高效稳定生产,针对三钢常用的八种铁矿粉的高温基础性能进行了相关研究。研究结果表明,矿种和铁氧化物赋存形态的不同均会影响到矿粉的高温基础性能,A 1矿粉内部褐铁矿含量较高,高温反应性较好,最低同化温度较低;磁铁矿粉的最低同化温度都达到了1300℃以上,液相生成能力和流动能力都较好,尤其B 1液相流动性指数达到了5.59,各铁矿粉之间存在烧结互补特性。研究铁矿石的高温基础特性为优化烧结配矿提供了技术依据,基于检测结果,确定了矿粉配比为外购富矿粉∶国内精矿粉=8∶2,后续可根据性价比对配比进行微调。

包钢7号高炉停炉放残铁实践

包钢7号高炉死铁层较深,为缩短工期,减少停炉后扒除炉缸残存渣铁工作量,采取降料线放残铁的停炉方式。放残铁是高炉停炉操作中最重要的环节之一,放残铁效果好坏直接影响炉缸清理时间。文章主要介绍了包钢7号高炉停炉放残铁流程。前期的准备工作包括活跃炉缸、确定残铁口位置、残铁量计算、残铁沟的制作等,对高炉停风后炉皮以及冷却壁的切割、残铁口泥套的制作以及整个残铁排放过程做了详细介绍。7号高炉放残铁过程实现了安全、有序,停炉后清理炉缸时发现炉缸内基本未见残铁,表明本次放残铁取得了良好的效果,为今后高炉大中修放残铁积累了经验。

液-固相法合成LiMn_(0.6)Fe_(0.4)PO_(4)的性能

磷酸锰锂(LiMnPO_(4))材料的电导率低且充放电过程易发生Jahn-Teller效应,导致电化学性能不理想。通过液-固相法合成磷酸锰铁锂(LiMn_(0.6)Fe_(0.4)PO_(4))正极材料,并对晶体结构、放电曲线特性、循环性能等进行分析。Fe均匀地掺入Mn位形成固溶体,样品的常温电化学性能得到改善。在2.0~4.3 V循环,0.1 C倍率下的放电比容量为156.5 mAh/g;以1.0 C倍率循环2000次,容量保持率超过80%。容量衰减主要源于循环过程中正极材料颗粒产生裂纹及颗粒粉化。