Recent collaborative researches between Japanese universities and steel industry on the iron ore agglomeration process

The properties of iron ores used in ironmaking process have been drastically changed in the past couple of decades.Especially,the change has become significant in the last few years because of the considerable increase in the world steel production.The property change of the iron ore is mainly caused by the depletion of the hard and high-grade lump hematite ores.It has led to the increasing use of ores containing a larger amount of goethite/limonite,i.e.,hydro-oxides of iron.Typically,the proportion of pisolitic ores,which are course limonitic ores,has remarkably increased by several times in Japan.Further,large deposits of the fine goethite ores called Marra Mamba have been developed in Australia and exported to Asian countries.Such trends will be continued in future.Since the change of the ore properties affects not only to the productivity and yield of the sinter but also its metallurgical properties in the blast furnace,further improvement in the sintering technology/ process is required including the preliminary treatment process of raw materials.In order to make wide researches concerning the above issues,the research project 'New Sintering Process through Designing of Composite Granulation & Bed Structure' was formed in the ISIJ,which was the collaborative project between Japanese steel companies and several universities.The project was started in 2005 and carried on the wide range of studies for three and half years.Its main objects are the characterization of pisolitic/goethitic ores and the understanding the behavior during the iron ore sintering process.Further,considering the ore characteristics,some basic researches on the optimum designs of raw material blending,granulation,bed structure,and the metallurgical properties of the produced sinter were performed.The project have invented the technical principle of a new sintering process, namely MEBIOS(Mosaic EmBedding Iron Ore Sintering Process),characterized by the composite granulation and bed-structure,aiming to cope with the drastic shift of the ore properties.Another big issue fallen on the steel industry is the global warming.CO,emission from steelmaking industry occupies about 15%of the total value of the artificial emissions in Japan and therefore its reduction is urgently required.In order examine the possibility to minimize or to reduce further the CO_2 emission from the iron ore sintering process,the research project 'Technological Principle for Low-Carbon Sintering' has been formed since 2009 in the ISIJ.In this project,the analyses of the combustion rates of carbonaceous materials and heat transfer in the sintering bed are first examined by referring the previous studies.Further,experimental works will be conducted on the combustion/oxidation characteristics of biomass charcoal,some organic wastes,steel can scraps,mill scale and partially reduced iron ores as alternative agglomeration reagents of coke and anthracite coal.The effect of their use on the sintering process will be evaluated systematically.It is expected that the structural changes of the sintering bed is considerably different between carbonaceous materials,which disappear during combustion leaving a little amount of ash components and metallic iron bearing materials,which increase the mass and volume during its oxidation. Previous studies showed that the use of metallic iron bearing materials such as steel can scrap and mill scale led to significant decreases in the production rate.This project examines the characteristics of such changes of the sintering bed structure and mineral phases and main process parameters,which govern such phenomena.Further, it searches for a new process principle to overcome the demerits and realize the significant reduction of CO_2 emissions from the iron ore sintering process.In the symposium,summary of activities and the major results and progresses of the above two research projects will be introduced.

Influences of seed size and number on agglomeration in synthetic Bayer liquors

By means of Malvern laser particle size analyzer and scanning electron microscopy, the influences of seed size and number on agglomeration in Bayer process were investigated. Agglomeration is almost finished in 8h, seeds, below 5μm, especially below 2μm, gather together rapidly and almost disappear in 8h. In the same supersaturation of aluminate solution and seed size, the smaller the number of seed is, the bigger the degree of agglomeration is. With the same primary number of seed, the agglomeration of larger seed is superior to that of small seed, and the agglomeration does not happen among the coarse seeds. The agglomeration mainly happens among fine particles, and the combinations among the fine particles are unconsolidated.

Effects of temperature and initial molar ratio of Na_2O to Al_2O_3 on agglomeration of fine Al(OH)_3 seed in synthetic Bayer solution

Fine Al（OH）3 crystals were aggregated from supersaturated aluminate solution in the batch reaction tanks. By means of laser particle size analyzer and scanning electron microscopy, the influences of temperature and initial molar ratio of Na2O to Al2O3 （aK） on agglomeration of fine seed in Bayer process were investigated. The results show that agglomeration is almost finished in 8 h, and seeds with size less than 2 μm are easily aggregated together, and almost disappear in 8 h under the optimal process conditions. In the aluminate solution with the same moderate initial aK, when the reaction temperature reaches 75 ℃, the secondary nucleation does not occur, and the effect of agglomeration is better. And at the same reaction temperature, when the initial aK is 1.62, the initial supersaturation of aluminate solution is moderate, the binders on the surfaces of the seed are enough to maintain the agglomeration process, and the agglomeration degree is better. From SEM images, agglomeration mainly occurs in the fine particles, the combinations among the fine particles are loose and the new formed coarse crystal shapes are irregular.

Agglomerate control in the complexing sol-gel process

Nanometer ZrO2 - 8% Y2O3 (mole fraction, % ) powders were prepared by the EDTA (ethylenediaminetetraacetic acid) sol-gel process. Effects of the addition of ethylene glycol on agglomerate control was investigated. The results showed that because of the replacement of hydrogen bonds with ethylene glycol in the polymerized gel, gel stabilization and homogeneity were improved and close approach of gel particles was prevented, which led to reduction of hard agglomerates to some extent. Calcined at 4OO t for 2 h and 700 C for 2 h, the powders had a specific surface area of 35 m2/g, average particle size of 28 nm, and median particle size (d50) of 0. 44um with very sharp distribution, mostly being soft agglomerates.

Mechanisms of composite agglomeration of fluoric iron concentrate

The effect of composite agglomeration process(CAP) on fluoric iron concentrates sintering was investigated.The yield and quality of the sinter are greatly improved when using CAP assisted with heat airflow and enhancing magnesium oxide(MgO) contents.For conventional sintering of fluoric iron concentrate,due to lower viscosity of binding phase and higher fluidity of liquid phase,the sinter is formed with large thin-walled holes and the strength of the sinter is deteriorated consequently.The novel process forms composite agglomerate in which acid pellets are embedded in basic sinter.The pellets are solid with interconnecting crystals of hematite(Fe2O3) and magnetic(Fe3O4).For basic sintering,after adding MgO,the viscosity of the melting phase increases and the fluidity decreases;and calcium and aluminum silico-ferrites and magnesium ferrite are formed with perfect crystals and good sintering microstructure.

AN INVESTIGATION OF THE HYDROPHOBIC AGGLOMERATION CHARACTERISTICS OF EASY DEGRADATION COAL FINES IN WATER

The separation of ultrafine coal from three Chinese coal samples of easy degradation coal fines in water has been investigated by the application of a hydrophobic agglomeration process. In addition to yielding clean coal with high recovery, this process requires significantly less oil concentration for agglomeration (less than 0.4% in oil-water weight ratio) and produces stabler agglomerates than general oil agglomeration process, the cost of the oil would no longer be an important consideration for its commercial application. Neutral diesel oil was used to make oleophilic coal particles agglomerated with good rejection of clay minerals under little oil consumption and certain agitation speed at 2000 r/min. An important advantage of this process compared with other cleaning fine coal methods is that it can extremely reduce or eliminate the effects of coal degradation and some clay minerals on coal preparation.

预造球强化难制粒精矿烧结工艺

随着进口铁矿石价格的增长,充分利用廉价的难处理铁矿资源成为钢铁企业降本增效的关键。本文针对难制粒精矿在烧结中利用率低的问题,在复合造块法的基础上开发了预造球工艺,显著提高了难制粒精矿的配入量,有效改善了制粒效果与烧结产、质量指标。研究表明,在难制粒精矿配比达到36%时,采用预造球制粒可以使准颗粒平均粒径提高1.53 mm,透气性指数提高0.17。在此基础上,垂直烧结速度提高13.97 mm/min,利用系数提高0.815 t/(m^(2)·h),转鼓强度提高3.39%。预造球烧结中,由于难制粒精矿的分离,常规制粒料部分的制粒性能得到优化,局部碱度得到提高,形成大量的针柱状铁酸钙。在常规制粒料与球团料交界处固相固结与液相固结同时存在,铁酸钙与铁氧化物相互交织,形成球团嵌入式分布的成品矿结构,具有良好的成矿效果和强度性能。

基于机器学习的涉海企业类型识别及其空间组织特征的城市比较研究

在推进海洋强国建设的进程中,海洋产业是海洋经济增长的最直接对象,而其空间布局与产业组织特征的研究是最具基础性的工作之一。选取4个代表性城市为研究区,基于海洋企业的工商登记信息,爬取空间坐标构建POI产业信息数据库。使用人工神经网络等机器学习算法识别各企业所属的行业,综合运用GIS空间分析方法,分析海洋产业集群的空间分异性规律。结果表明:1)从空间格局特征看,总体呈“大分散、小集聚”的均衡格局,多类别对比显示企业选址存在行业集聚性,同时具有空间极化特征,陆海关系上体现为海岸带高密度单峰或“海岸带-市中心”双峰分布格局。2)从空间组织模式看,产业集群存在与人口规模、行政等级相对应的多层次等级位序特征;除单核心结构外,多核心结构中一般表现为“主-次双核心”或者“一主多次放射状”,核心区间产生空间联系形成多节点的轴线或网络结构。3)从空间匹配关系看,椭圆面积与城市面积呈正相关,椭圆长轴方向与海岸线延伸方向相近,产业分布与城市行政中心、港口等交通枢纽、海湾地形、海岸线等空间要素存在明确的匹配关系。

保税区与出口加工区对工业绿色转型影响研究

保税区与出口加工区不仅是工业发展政策的空间载体,更是驱动地区工业绿色转型的关键。本文基于2004—2022年省级面板数据,采用双向固定效应模型实证分析了保税区和出口加工区对地区工业绿色转型的影响及其作用机制。结果表明:保税区的产业集聚效应、FDI技术溢出效应和制度溢出效应促进地区工业绿色转型,出口加工区的产业集聚效应促进地区工业绿色转型;保税区对地区工业绿色转型的影响存在明显的地区和时间异质性;长江经济带发展战略联动效应放大了保税区和出口加工区对地区工业绿色转型的影响;保税区和出口加工区对地区工业绿色转型的影响存在明显的协同效应。各地区政府应在保税区和出口加工区内培育产业集群,着力推动产业转型并发挥技术创新引领作用。

黔北某菱锰矿高梯度脉冲磁选及影响因素研究

对贵州北部某典型低品位菱锰矿进行了工艺矿物学分析,结果表明,矿石中锰品位为12.82%,Mn/Fe3.93,P/Mn0.02,S/Mn0.15,Mg/Ca0.32,矿石属于高铁高磷高硫高硅高黏土菱锰矿。菱锰矿多呈泥晶集合体结构,矿石中Mn89.47%赋存于钙菱锰矿中,Mn与Ca类质同象严重,菱锰矿属于不均匀粒度分布。采用“一粗(1.2T)一扫(1.3T)”高梯度脉冲磁选流程,得到回收率85.01%、品位为18.19%的磁选精矿指标。经AMICS产品特征研究结果表明,精矿品位及回收率难以提高的主要原因是菱锰矿中Mn被Ca类质同象,该特征造成菱锰矿无法实现单体解离,使菱锰矿中钙质随磁选进入精矿,方解石及白云石中锰质难以回收,降低精矿品位及回收率。其次该矿石嵌布粒度不均匀,部分白云石及微晶黄铁矿在钙菱锰矿中分布,造成菱锰矿与脉石矿物形成连生体,难以实现磁选分离,恶化精矿指标;最后是菱锰矿精矿锰品位的提升需增加磨矿细度实现单体解离,而矿石中存在大量黏土矿物、颗粒过细加重泥化、团聚现象,造成细粒菱锰矿颗粒与脉石矿物形成异质团聚体,当团聚体的体积比磁化率达到磁选回收界限时,团聚体中脉石矿物也被带入精矿降低质量,当团聚体的体积磁化率未能达到磁选回收界限时,团聚体中菱锰矿随脉石矿物被水流带走,造成跑尾降低精矿回收率。

疏水-亲水分选研究进展

这是一篇矿物加工工程领域的论文。疏水-亲水双液分选相较于泡沫浮选在微细粒(煤30~50μm、非煤矿物10~20μm)回收方面有较大优势。基于油团聚、奥蒂斯卡工艺、驱替脱水、双液浮选和低沸点非极性液体回收等开发的新型疏水-亲水双液分选技术(Hydrophobic-hydrophilic Separation)能够促使超细粒团聚体在双相系统中充分破碎再分配,从而达到驱水除杂的双重目的。从HHS选煤过程、团聚体破碎理论、疏水液体回收可行性、相较于泡沫浮选和油团聚的技术优势以及细粒煤脱水技术等方面对疏水-亲水分选近些年的发展进行梳理比较,以期能够为下一步发展提供参考建议。

Transient flameout process of boron-magnesium agglomerates during combustion in oxygen-rich atmospheres

In this study,boron–magnesium agglomerates with varying mass ratios were prepared by drying a micron-sized boron–magnesium mixed suspension,and the combustion process of these agglomerates under different oxygen-rich concentrations were investigated using a laser ignition system.The test results showed that when the mass fraction of magnesium powder in boron-magnesium agglomerates exceeded a certain threshold(between 2%and 5%),flame extinction and reignition occurred after a significant reduction in the agglomerate volume during combustion.This process is referred to as the transient flameout process,which is affected by the magnesium content of the agglomerate and the oxygen concentration in the ambient atmosphere.An increase in the magnesium content or oxygen concentration makes this phenomenon more pronounced.During weakening of the flame intensity,a dark film gradually covered the particle surfaces.X-ray diffraction and elemental analyses of the cross-section and outer surface of the condensed combustion product suggested that the dark film is primarily composed of Mg-B-O ternary oxides.This film prevents direct contact between boron and oxygen,thereby inhibiting surface and gas-phase reactions and leading to the occurrence of the transient flameout phenomenon.

钢铁冶金流程及节能技术研究

随着中国经济和科学技术的不断发展,钢铁工业已成为中国最重要、发展最快的关键产业之一。然而,该行业属于高耗能行业,是全国六大高耗能行业之一。在冶金钢铁生产中,钢铁企业不仅要注重技术研发和动力支持,还要注重节能环保。针对钢铁冶金生产过程中的节能问题进行分析,深入探讨钢铁生产过程中节能技术的要点,通过应用烧结矿余热回收技术、低温余热回收技术和电机节能技术等节能技术,不断提高钢铁企业的生产效率,降低资源和能源的消耗。

基于AHP的技术创新生态链演进影响因素研究

本文探究影响技术创新生态链发展的关键因素,对于推动技术创新、技术创新生态链乃至技术创新生态系统的演进发展具有重要作用。本文在分析技术创新生态链演进影响因素的基础上,采用层次分析法,构建技术创新生态链演进评价模型,构造判断矩阵,计算各指标所占权重并进行一致性检验。结果发现,资源流转状况、节点创新能力、节点关系和组织管理水平是影响技术创新生态链演进的关键因素,可以通过提升以上四个方面的状况来促进技术创新生态链的演进。

农产品加工业集聚与农业现代化的耦合协调及其影响因素分析

农产品加工业向前连接农业、农村和农民,向后连接工业、城市和市民,横跨农业、工业和服务业,起着牵一连三的作用,在国民经济中占有重要地位。农产品加工业通过促进农村一二三产业融合延长了农业产业链,提升农业价值链,从而带动农业增效、农民增收,并改善农村环境,是解决“三农”问题的根本路径。文章基于2012—2020年面板数据,利用熵权法、区位熵、耦合模型等方法,对中国农业现代化和农产品加工业集聚时空演化进行分析,并探讨背后的影响因素。

高硒碲铜阳极泥协同高铜渣硫酸化焙烧工艺研究

高硒碲铜阳极泥在硫酸化焙烧过程中,产出的焙砂易烧结成大块状,且硒蒸出率较低。针对此问题,本研究利用高铜渣中单质铜含量高的特征,探索了铜阳极泥协同高铜渣硫酸化焙烧工艺,并进行了条件试验。试验结果表明,采用高铜渣协同硫酸化焙烧工艺处理铜阳极泥可行,在铜阳极泥与高铜渣质量比(以干重计)1∶0.1,硫酸与混合物浆化质量比0.85∶1,浆化时间60 min,四段焙烧温度分别为300℃、480℃、570℃、610℃,焙烧时间120 min等较佳工艺条件下,焙砂中硒含量可以降至0.1%以下。工业试验表明,产出的焙砂颗粒小且内部呈蜂窝状,铜阳极泥中硒得到有效蒸出,焙砂中硒平均含量由原来的6.67%降到0.09%,脱除率达98.65%。硫酸化焙烧过程中生成的粗硒纯度大于96%,可用于生产高纯度硒或者直接外售;生成的焙砂可通过球磨水浸分铜,分铜渣氯化分金回收金,分金渣氨浸分银回收银,最后将分银渣火法熔炼进一步回收有价金属。相较常规铜阳极泥硫酸化焙烧方法,本工艺实现了铜阳极泥中硒的深度蒸出,也实现了高铜渣的有效处理,具有推广价值。

珠三角城市群快速陆路交通一体化发展研究

快速陆路交通一体化是区域协调发展的先决条件和重要保障。为进一步构建适应我国城市群发展实践的区域陆路交通一体化评价方法和指标体系,清晰把握珠三角城市群陆路交通一体化发展中的问题,本文以珠三角城市群为研究区域,运用层次分析法、模糊综合评价等方法,分析与讨论珠三角快速陆路交通网络建设和管理服务的一体化水平。结果表明,珠三角城市群陆路交通一体化发展存在着基础设施建设不均衡、网络格局不协调、管理服务和政策协调体制不健全、成本分摊及利益共享机制不完善、协同治理相关机制匮乏等问题。研究成果可以从规划建设、协调保障和组织协同等方面为珠三角城市群快速陆路交通一体化管理和发展提供科学参考与决策支持,为我国区域性交通网络一体化规划、建设和管理等方面提供借鉴与实践经验。

集聚式多锚头钢横梁制造工艺研究

池州长江公路大桥主塔采用花瓶形,塔柱间钢横梁采用集聚式多锚头箱形结构,每个钢横梁上最多有10对锚固点(20个锚头)。通过对集聚式多锚头钢横梁的结构特点分析,确定了合理的横梁块体组装焊接顺序;通过焊接工艺评定试验确定了与母材匹配的焊接材料和焊接参数,保证了焊缝质量;通过对拼装胎架、锚箱精度控制、焊接变形控制等关键项点研究和有效技术措施的应用,确保钢横梁的外形尺寸符合标准和规范要求;先孔法栓接技术的实施,可大幅提高桥位钢横梁拼装效率。

The urbanization process of Bohai Rim in the 1990s by using DMSP/OLS data

This paper firstly derived urban information from Defense Meteorological Satellite Program/Operational Linescan System （DMSP/OLS） data in 1992, 1996 and 1998 with the support of statistical data, and then developed three basic urban models of polygon-urbanization, line-urbanization and point-urbanization in urban agglomerations from viewpoint of spatial analysis. The conclusions are as follows： （1） Urban patch numbers in the Bohai Rim increased from 1659 to 2053 with an annual average increase number of about 66. Meanwhile, the small urban patches accounted for a larger proportion in the region and the patch density increased fast. In addition, the urban barycenter of the region showed a moving trend toward northwest from 1992 to 1998. Urbanization in the Bohai Rim in the 1990s is fast and obvious. （2） Urbanization in the Bohai Rim can be reflected by three basic processes, i.e., the polygon-urbanization around the big cities, the line-urbanization around the transportation lines and the point-urbanization emerging in large areas. Of them, the polygon-urbanization has been in dominance. It is obviously within an effective range of 3-4 km surrounding the urban patches. The line-urbanization and point-urbanization in the region was relatively small, both of which showed an obvious increasing trend.

A Low Cost and Facile Preparation of Hydrophobic Silica Films and Powders by a Solution-based Process

Super-hydrophobic surfaces with water contact angle （WCA） higher than 150~ generated a lot of interests both in academic and in industry because of their self-cleaning functionality. Emphasis was given to the effect of pH value on the hydrophobic behavior of the obtained films or powders. At first, SiC）2 sols were prepared by diluted ammonia. We found that following the increase of pH value of sol from 8 to 9, WCAs of the obtained films increased from 121.8~ to 131.8~. Following the continued increase of the pH value of sol, precipitates began to appear and smooth film could not be obtained. The WCAs of the obtained powders could reach 121.7~, and through modifying by TMCS could further increase to as high as 165~ and the water sliding angle （WSA） was 2~. The results of SEM indicate that the hydrophobic properties of the powders without modifying by TMCS should be originated from the formation of nano/micron binary structure, i e, a micron- scale diameter and a nano-scale surface roughness. In this work we provide a better solution to fabricate super- hydrophobic silica coating surface with a simple method at low cost.