Importance of Mineralogical Data for Influencing Properties of Coke: a Reference on Si02 Polymorphs

SiO₂ occurs in coking coals as pure quartz and also in complex aluminosilicates. At coking temperatures, pure SiO₂ has several polymorphs (α‐ and β‐quartz and β‐tridymite) and transformations from one to another are accompanied by volume changes in the mineral matter that can lead to the formation of cavities and cracks in a coke matrix. These can weaken the coke physical strength and lead to a higher circulation of gases within the pieces. The grain size of the primary quartz crystals in a coal blend is also important for the estimation of coke strength: the larger the crystals that occur in a coal, the larger the cavities and cracks that will ensue (weaker coke). The occurrence of any given SiO₂ polymorph indicates the temperature of its formation and can be used to correlate other changes in coke‐forming compounds with certain temperatures. A high amount of free quartz in a coal blend can be considered a negative factor for coking. For a better understanding of the influence of bulk SiO₂ on coke quality, mineralogical (phase) analysis and quartz grain size measurements on coking coals can be helpful. Under the blast furnace conditions, SiO₂ polymorphs have no substantial influence on the coke physical strength.     

铁焦制备与高炉应用的研究进展

 钢铁工业长期面临着资源短缺和环境污染的的发展现状,实现节能减排和绿色冶金是钢铁工业实现可持续发展的重点。而高炉炼铁是钢铁工业节能减排的关键,急需研发低碳高炉炼铁新技术。复合铁焦是实现低碳高炉炼铁的一种新型碳铁复合炉料。高炉使用铁焦后可降低热储备区温度,提高冶炼效率,降低焦比,从而实现CO₂减排。综述了国内外铁焦制备与应用的研究进展,主要包括铁焦的制备工艺和高炉应用。归纳了各种铁焦制备工艺的特点。同时提出并研究了矿煤压块-竖炉炭化-高炉应用的冷压型铁焦制备与应用新技术。重点进行了冷压型铁焦的制备及冶金性能优化、高炉应用冷压型铁焦等试验研究。冷压型铁焦制备适宜的工艺条件为,质量分数为30%铁矿粉、45%烟煤1、10%烟煤2、10%烟煤3、5%无烟煤、5%沥青类黏结剂B混合加热至60 ℃,并进行冷压成型;成型压块再经竖炉1 000 ℃炭化4 h;获得抗压强度3 977 N、I型转鼓强度77.7%、反应性69.7%、反应后强(固定气化溶损量20%)42%的优质铁焦。高炉综合炉料中添加质量分数20%~30%冷压型铁焦,综合炉料熔滴性能明显改善。以上研究为铁焦实现工业化生产与低碳高炉炼铁应用提供了参考。     

高炉软熔带形态研究

对高炉软熔带形态进行了三维动态热模拟实验研究。结果表明，采用发展中心和中心加焦的装料制度，有利于形成位置较高的倒Ｖ型软熔带，可提高料柱透气性、降低炉内总压降，是增大喷煤量、疏导炉内煤气流、促进高炉顺行的有效手段。     

CFD Modelling and Analysis of Pulverized Coal Injection in Blast Furnace: An Overview

In order to understand the complicated phenomena of pulverized coal injection (PCI) process in blast furnace (BF), several mathematical models have been developed by the UNSW and BSR cooperation. These models are featuring from coal combustion in a pilot‐scale test rig, to coal combustion in a real BF, and then to coal/coke combustion in a real BF, respectively. This paper reviews these PCI models in aspects of model developments and model applicability. The model development is firstly discussed in terms of model formulation, their new features and geometry/regions considered. The model applicability is then discussed in terms of main findings followed by the model evaluation on their advantages and limitations. It is indicated that the three PCI models are all able to describe PCI operation qualitatively. The model of coal/coke combustion in a real BF is more reliable for simulating in‐furnace phenomena of PCI operation qualitatively and quantitatively. Such model gives a more reliable burnout prediction over the raceway surface, which could better represent the amount of unburnt char entering the coke bed. These models are useful for understanding the flow‐thermo‐chemical behaviours and then optimising the PCI operation in practice.     

宝钢高炉200kg/t以上喷煤比的实践

高炉喷煤能大幅度降低入炉焦比,减少对日益匮乏的焦煤资源的依赖,是炼铁降低成本的最有效手段,已成为高炉炼铁技术进步的重要一项内容。宝钢高炉喷煤始于1992年5月的2号高炉,虽然起步较晚,但经过多年来的不断努力、科学探索和生产实践,从优化喷吹煤种、控制混合煤成分、改善喷煤设备性能和操作参数、制订原燃料质量标准和重新设计高炉操作制度等方面着手,高炉喷煤比一年上一个台阶。1998年以来,高炉喷煤比持续稳定在 200kg／t,1号高炉与此同时还在高产能、低燃料消耗下取得了月均喷煤比260kg／t的好成绩。     

鞍钢高炉喷吹水熄焦粉的生产实践

为探索高炉喷吹水熄焦粉的可行性,开展了5%~15%水平下的水熄焦粉高炉喷吹用配煤优化实验室实验及工业喷吹试验。结果表明,在现有配煤基础上,最适宜的配入量为15%,鞍钢新2#和新3#高炉喷吹水熄焦粉后,煤气利用率分别提高0.24%和0.58%,燃料比下降0.71 kg/t和1.82 kg/t,水熄焦粉可用于高炉喷吹。     

高炉焦炭在铁水中溶解行为研究现状及展望

 在当前及未来大型高炉高冶炼强度的条件下,加快焦炭在铁水中的溶解速率、提高高炉炉缸铁水的碳饱和度是削弱碳不饱和铁水对炉缸炉衬侵蚀、保证炉缸正常工作及延长高炉寿命的重要措施,同时可以为下游的炼钢工序提供部分热量来源。首先对国内外焦炭在铁水中溶解的试验和模拟研究方法进行了概括,然后对焦炭自身结构性能、焦炭中矿物质、铁水的物理性质等影响焦炭溶解速率的因素进行了详细分析。结果表明,碳结构的有序度和铁水温度的升高有利于焦炭的溶解,而焦炭中矿物质及铁水中硫、磷等元素的存在会抑制铁水的进一步渗碳。研究结果为高炉操作者理解焦炭在铁水中的溶解行为提供借鉴,指导钢铁工业的节能减排。     

低质焦炭下高炉炉尘及喷吹煤粉利用率

 为了研究低质焦炭条件下高炉喷吹煤粉的利用率,对安钢高炉两批低质焦炭及炉尘进行取样分析。测定了焦炭的常用质量评价指标及炉顶除尘灰的碳质量分数,并采用岩相测试技术分析了炉尘未消耗煤粉和焦炭的不同结构形态,定量地给出了炉尘中未消耗煤粉和焦炭颗粒的质量分数。结合安钢配煤现状,考察了3种高炉所用喷吹原煤不同粒径的燃烧率,并讨论了不同烟煤配比下挥发分质量分数对不同粒径煤粉燃烧率的影响,为低质焦炭条件下提高煤粉利用率提出合理化建议。结果表明,低质焦炭条件下,炉尘碳质量分数明显偏高并含有较多未消耗煤粉;炉尘中的未消耗煤粉分为热变煤颗粒和残炭颗粒,而未消耗焦炭则以镶嵌结构为主;控制焦炭质量波动、减少焦炭水分质量分数有利于降低炉尘碳质量分数;安钢喷煤首选无烟煤应为B煤,喷吹煤粉的挥发分适宜控制在17%左右。     

高炉富氧喷煤后的焦比变化

通过对高炉富氧喷煤的能量计算，研究了高炉富氧喷煤后的焦比变化，讨论了富氧喷煤对焦比的影响，富氧喷煤后焦比降低量及煤粉燃烧率对及富氧喷煤效果的影响。     

石钢高炉富氧喷煤的工艺特点及冶炼实践

介绍了石钢高炉煤粉制备工艺改造和煤粉喷吹工艺的特点及富氧喷煤的冶炼初中。石钢喷吹煤粉工艺采用多管路浓相输送技术，可实现按风口调节和控制喷煤量，具备喷吹烟析条件；针对富氧喷煤后高炉行程的变化，采取了相应措施，取得增产节焦的效果。     

韶钢750 m3高炉喷煤系统技术进步

韶钢750m^3高炉喷煤系统采用了自动配煤、中速磨制粉、低压长袋收粉器收粉、浓相输送等国内先进技术．喷煤系统投产后，高炉煤比达到了150kg／t以上，入炉焦比降到400kg／t以下，取得了良好的经济效益．     

提高高炉焦炭质量的研究

分析了武钢高炉喷煤的现状和发展规划,以及提高焦炭质量的必要性。根据不同配煤比条件下炼焦试验和改变工艺条件下炼焦试验的结果,探讨了生产中提高焦炭质量的途径和有待进一步研究的问题。还对２０ｋｇ试验焦炉焦炭与６ｍ、４．３ｍ焦炉焦炭热反应性ＣＲＩ和反应后强度ＣＳＲ的相关性进行了研究。     

高炉与KR双流程联动优化脱硫

 基于首钢京唐高炉工序与KR工序脱硫条件,对双流程的脱硫特点及经济性分别进行分析,发现焦炭为高炉硫负荷的主要来源。降低焦比或减少高硫炼焦煤的配比,是降低高炉硫负荷的有效措施,当铁水中[w(S)]由0.01%升高至0.05%时,高炉工序吨铁脱硫成本迅速下降,而当铁水中[w(S)]由0.06%变化至0.10%时,吨铁脱硫成本下降趋势变缓;KR脱硫吨铁成本随铁水中[w(S)]增加而逐渐升高。硫负荷为4 kg时,双流程综合脱硫成本最低时的铁水中[w(S)min]为0.067%,且[w(S)min]随硫负荷的增加而升高。当考虑炼焦配煤的采购成本时,由于硫质量分数高的炼焦配合煤采购成本较低,当采用高硫煤炼焦时,炼焦配煤带来的成本降低,不仅可以抵消由于双流程脱硫任务量增加而带来的成本增加,还可以使综合脱硫成本降低。     

Ratio between Unconsumed Coal and Coke Particle in BF Dust

The particle size distribution in BF dust (gravitational dust and sludge) at Baosleel was measured. 85 % of the particles in the sludge are smaller than 149 μm, while 60 % of the particles in the gravitational dust are in the range 74~297 μm. It was found by microscopic analysis that the structure of unconsumed coal is different from that of the coke particles. Based on the carbon status in BF dust, the proportion of carbon from unconsumed coal and coke particles was determined by microscopic analysis at different PCI rates at Baosteel. The unconsumed coal ratio in the carbonaceous substances (Φ) in BF dust at Baosteel could be determined and then the percentages of unconsumed coal and coke particles in BF dust were obtained.     

CaO对神东烟煤燃烧和熔融性能的影响

为了研究CaO对神东烟煤燃烧和熔融性能的影响,通过试验的方式研究了添加不同含量CaO后神东烟煤燃烧性和熔融性能的变化情况。使用FactSage热力学计算软件研究了添加不同含量的CaO对煤粉熔融性能的影响。结果表明,CaO的添加对两种神东烟煤的燃烧性有非常明显的催化作用。通过观察添加CaO后煤中的矿物变化情况可以发现,随着CaO的添加,CaO与煤灰中原有的矿物发生反应生成新的物相,从而对对煤的熔融性能产生影响。并且随着CaO的添加,煤灰的熔融特性温度显示出了先降低后增加的趋势,煤灰中CaO质量分数为30%~35%时,完全熔化温度达到最低点。     

首钢1号高炉降低焦比实践

首钢1号高炉由于采取了改善原燃料条件、优化高炉操作、提高风温、富氧喷煤等措施，使得煤比大幅度提升、焦比显著下降。2005年11月，1号高炉煤比提高到136kg／t、平均焦比降低到322kg／t。     

关于提高焦炭质量的探讨

随高炉喷煤技术的发展，喷煤量增加，焦比大幅度降低，焦炭在高炉中的负荷加重，焦炭质量面临更为严峻的要求。本文就我国焦炭质量的状况及今后有关提高焦炭质量的问题做些探讨。     

优化配煤结构 降低配煤成本 改善焦炭质量

论述了近年来鞍钢进行的优化配煤结构的科研工作。以焦炭在高炉中劣化过程的研究为依据,转变对焦炭质量指标和配煤技术的认识。在配煤中,多配多价格较低的瘦煤和低灰、低硫的１／３焦煤;减少价格较高的强粘结性焦煤和肥煤的比例,使配煤原料成本大幅度降低,焦炭灰分下降。鞍钢１９９９年焦炭质量达到历史最好水平。同时炼铁高炉主要技术经济指标也达到历史最高水平。     

混喷技术在天铁高炉中的应用

叙述了混喷技术在天铁高炉上的应用过程。通过优化高炉混喷工艺,强化混喷后的冶炼操作等措施,使天铁高炉在入炉品位降低等不利情况下,实现了平均煤比164.6 kg/t,焦比362.9 kg/t,综合焦比493.6 kg/t,提高了煤比,降低了焦比,较大程度地提高了天铁高炉喷煤技术水平。     

High Temperature Properties of BOF Slag and its Behaviour in the Blast Furnace

Slag formation in the bosh and raceway is an important issue in the blast furnace process. SSAB works in Luleå operate with 100 % olivine pellets. A small amount of basic fluxes is added from the top, slag and limestone are used. To improve the control of slag formation, a concept with injection of BOF slag was evaluated and tested in the LKAB experimental blast furnace (EBF). In this paper, the behaviour of BOF slag as a slag former, when it is top‐charged or tuyere‐injected, is evaluated based on the results from a laboratory study including reduction tests, softening and melting tests, XRD analyses and SEM analyses. Samples taken from the EBF during excavation, and with a burden probe during operation, are examined. The evaluations show that the melting point of BOF slag is quite low and will not be increased, because of the partial reduction that occurs in the BF shaft. When carbon is present at high temperatures, reduction proceeds and a high basicity slag with a high melting point, consisting of di‐ and tricalcium silicates, is formed. When pellets with a basicity of B2 ~ 1 are used, a slag with similar properties can be formed as a result of interaction with the BOF slag. BOF slag in combination with olivine pellets with a low basicity generates a slag with intermediate basicity and the reduction of iron oxides in the slag has a small effect on the melting temperature. The BOF slag decreases the melting point of coal and coke ashes.