不同FeO含量的炉渣对焦炭侵蚀作用的研究

模拟了高炉中不同FeO含量的炉渣对焦炭侵蚀作用的影响.结果表明:随着炉渣中FeO含量的增加,焦炭气孔壁的破坏逐渐加剧,焦炭的微观结构受到破坏.利用SEM扫描及能谱分析可知,铁元素已侵蚀到焦炭内部,因此炉渣中FeO含量的变化对焦炭的侵蚀影响不可忽视.     

高炉焦炭石墨化过程中的微观组织和冶金性能演变

当前低碳高炉冶炼条件下使得炉内焦炭层变薄,恶化了料柱的透气透液性,焦炭在炉缸高温区石墨化过程中产生的焦粉是导致该现象出现的主要原因之一.为了研究焦炭在高炉下部的石墨化过程对其在炉缸内的冶金性能影响,研究了1100~1500℃不同温度下焦炭的石墨化度改变;同种焦炭石墨化程度与焦炭反应性及反应后强度之间的关系;不同石墨化度焦炭与碱金属侵蚀之间的关系;观察并分析了试验后不同焦炭试样的微观形貌.结果表明,随着温度的升高,焦炭石墨化程度加深,且温度每升高100℃,焦炭石墨化度约提高1.8倍,层间距d₀₀₂值约降低2%,微晶结构层片直径L_a值约提高3%,层片堆积高度L_c值约提高15%;焦炭的表面气孔减少,特别是大气孔减少,焦炭表面镶嵌组织减少,各向同性组织增多,焦炭的结构有序化程度增强.随着焦炭石墨化程度的加深,焦炭的反应性逐渐减小、反应后强度逐渐提高,焦炭表面的劣化情况减弱,生成的大气孔减少,气孔壁破坏趋势减弱.碱金属对焦炭的反应性有促进作用,使焦炭的反应性提高,反应后强度降低.而焦炭的石墨化对焦炭的碱侵害具有一定的抵抗作用,降低了焦炭表面的劣化程度.      

焦炭气孔结构对热性能指标的影响

通过40kg试验焦炉炼焦试验，研究了焦炭气孔结构对热性能指标的影响。结果表明，随着气孔率及焦炭平均气孔直径的增加，焦炭反应性增加，反应后强度下降，热性质恶化；随着焦炭平均气孔壁厚度的增加，焦炭反应性降低，反应后强度提高，热性质改善。配煤结构、炼焦条件、熄焦方式等是影响焦炭气孔结构的主要因素。     

ZnO和PbO对焦炭热性能的影响研究

采用国标方法对添加不同剂量ZnO、PbO的焦炭进行焦炭热性能检测,并对测试前后的焦炭进行显微气孔大小分布、气孔壁厚度分布的检测、分析和对比,试验表明:ZnO、PbO对焦炭热性能均有正催化作用;通过对焦炭的显微气孔大小分布、气孔壁厚度分布的对比和分析,ZnO、PbO在反应时使焦炭气孔变大、气孔壁变薄,进而使得焦炭反应性升高,反应后强度下降。     

焦炭在白云鄂博矿高炉冶炼中的热态性能变化

 冶金焦炭已经成为现代高炉炼铁技术所需的必备原料之一,被喻为钢铁工业的“基本食粮”,具有重要的战略价值和经济意义。随着低碳时代的来临和大喷煤技术的运用,焦炭的功能逐渐被替代。为了保证炉内的透气性以及透液性,作为高炉软熔带的“百叶窗”,焦炭作为料柱骨架和通道的作用更为突出,因此深入理解焦炭在白云鄂博矿高炉冶炼过程中的热态性能变化对指导白云鄂博矿的高效冶炼至关重要。以从包钢4号高炉中取出的入炉焦与风口焦为研究对象,使用X射线衍射仪、热重立式炉、扫描电镜、能谱仪等分析手段,对比研究了它们的基础特性、灰分的主要物相、反应性(CRI)与反应后强度(CSR)、微观孔隙结构及碱金属的含量及分布,从而得到焦炭在白云鄂博矿冶炼中的热态性能变化。结果表明,高炉中的焦炭在下降过程中发生气化反应,灰分含量提高,挥发分含量降低,SiO₂含量显著降低,但是CaO、K₂O、Na₂O、MgO等碱性氧化物含量有所增加。二次加热前期焦炭发生氮气吸附,质量没有减少反而增加;后期焦炭发生碳气化反应,质量快速下降,风口焦的反应性提高,反应后强度降低。风口焦表面出现了类似蜂窝状的孔隙,且孔隙分布不均匀,特别是被渣铁侵蚀的焦炭基质,其气孔壁变得粗糙,孔隙出现合并。碱金属在风口焦中富集,碱性氧化物含量增加。风口焦石墨碳所对应的(002)衍射峰半峰宽急剧减小,扁平峰消失,峰形尖锐。晶体结构趋向有序,石墨化程度提高。     

超大型高炉风口焦炭取样分析研究

为恢复炉况及探讨超大型高炉冶炼规律,对首钢京唐公司高炉进行了风口焦炭取样分析,研究了其入炉焦炭热强度与焦炭反应性、焦炭冷强度与焦炭耐磨强度之间的关系;探明了风口焦炭的粒度、劣化度及渣铁滞留量;探索了渣铁滞留量与渣铁体积、风口焦炭粒度、煤比及炉渣二元碱度的关系;分析了炉缸径向焦炭粒度分布、风口前高透气性区长度、炉缸透气性等;根据上述研究结果,提出了高炉操作建议并得到应用。实践结果表明:风口焦炭取样分析可以作为高炉操作调整的重要参考。     

焦炭气孔结构对热性能指标的影响

通过40kg试验焦炉炼焦试验，研究了焦炭气孔结构对热性能指标的影响，研究表明，焦炭气孔率、平均气孔直径、平均气孔壁厚度等，对焦炭热性能指标影响很大。配煤结构、炼焦条件、熄焦方式等是影响焦炭气孔结构的主要因素。     

锌对焦炭冶金性能的影响

 为了探究锌对焦炭冶金性能的影响规律和机理,对焦炭进行了不同锌质量分数下的吸附,并依据国标开展了焦炭反应性及反应后强度检测试验。结果表明,锌对焦炭的气化反应有正向催化作用,同时会导致反应后强度下降。通过光学显微镜、X射线衍射及BET比表面积检测,分析了负载锌后焦炭的微观形貌、微晶结构和气孔演变规律,发现锌会侵蚀焦炭基质,具有扩孔作用。最后运用第一性原理计算对锌的催化机理进行了解释。     

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。     

COREX风口焦(半焦)特性解析研究

对COREX风口焦进行EDS、XRD、Raman分析及气孔结构表征,并与入炉燃料性能进行对比。结果表明,入炉焦中碳含量明显高于风口焦中各个粒级的碳含量;风口焦中硫含量低于入炉焦,焦中硫发生了迁移。风口焦XRD和Raman分析表明,20~40 mm粒级焦炭(半焦)石墨化程度较高,而在5~20 mm和5 mm两个粒级范围焦炭(半焦)无序化程度高;风口焦的R值与粒径之间没有明显的关联;20~40 mm粒级风口焦气孔率最大。入炉燃料与风口焦的粒度及灰分分析表明,山西焦在COREX炉内降解速度较宝钢焦快;风口焦的灰分含量明显高于入炉燃料,且随风口焦粒径的降低而增加。     

莱钢高炉风口取样研究

通过风口取样,对莱钢1#1 080 m3高炉风口区域焦炭、碱金属以及炉渣成分的变化情况进行了详细的检测分析。结果表明,在高炉结瘤操作时,高炉风口区焦炭粉化严重,死料柱的透气性与透液性差,风口焦炭碱金属含量增加;高炉炸瘤后,随着喷吹煤比的增加,风口焦平均粒度有减小趋势;风口焦样粒度沿高炉径向向炉缸中心减小;风口边缘渣碱度比靠近中心渣碱度低。     

高炉入炉焦/风口焦微观结构与气化反应性对比

摘要：以同一座高炉2次休风所取的入炉焦和风口焦为研究对象,采用XRD、SEM EDS、N2吸附、热分析等方法比较分析不同样品的碳化学结构、碱金属富集程度、孔隙结构、CO2气化反应性,探究了焦炭在高炉中反应性变化程度和影响因素。结果表明：风口焦炭与入炉焦炭相比,气化反应性显著升高,比表面积增大,碳结构有序化程度升高,碱金属含量提高;金属钾在风口焦炭边部的存在形式以可溶性盐为主,在焦炭内部以钾霞石为主;入炉焦各部位差异较小,而风口焦边部、中部、芯部的气化反应性和结构性质存在显著差异,表明其各部位在高炉中所经历的气化反应过程不同;风口焦中碱金属含量为影响气化反应性的最主要因素,次要影响因素为碳化学结构和孔隙结构。     

鞍钢朝阳钢铁高炉风口内径向取样分析

 为了解炉内渣铁分布以及径向焦炭性能劣化状况,对朝阳钢铁公司1号高炉取样设备组成、现场安装以及风口内部径向取样过程进行了说明。对所取风口焦的成分、粒度组成、热态性能等进行检测,并对所取不同部位风口焦微观结构及石墨化程度进行分析,结果表明,1号高炉风口回旋区长度为1.7 m,风口焦平均粒度为16.12 mm,热态反应后强度为12.30%。对比鞍钢本部其他在产高炉,明显存在着回旋区长度偏短、风口焦粒度较小及热态性能较差等问题,焦炭性能较差是影响高炉稳定顺行的重要原因之一。     

Microstructure characteristics of dead stock coke from blast furnace

In order to reveal the relationship between the macroscopic properties and microstructure of dead stock coke, the differences between dead stock coke samples and feed coke samples were compared by industrial analysis, pore structure analysis, BET detection, XRD detection and SEM observation, etc. Dead stock coke samples and feed coke samples were both sampling from the stop experiment of a schreyerite BF in one factory in Xichang. Experimental results show that comparing with feed coke samples, the dead stock coke has significant differences in microcrystalline structure, stomatal structure, mineral distribution. The content of ash in dead stock coke increases, the number of super- atmospheric pores (pore size greater than 1000??m2) increases, the number of micropores (pore size of 0-50nm) and mesopores (pore size of 50-300nm) increase, and the crystallite size increases by about 4 times. In addition, the outer pores of the dead stock coke also adsorb a large amount of slag iron minerals, and the minerals are mainly magnesite, perovskite and iron carbon compounds. Then after the coke drops to the dead column area and stays for a long time, its porosity increases and the degree of graphitization increases.     

Microstructure of a Variety of Cokes After Alkali Enrichment

 It is difficult to distinguish tamping coke and top charging coke by conventional testing methods, such as cold strength, abrasion resistance, reactivity and strength after reaction. Some of tamping coke′s properties were even better than those of top charging coke, but from practical using effects of blast furnace, tamping coke was not as good as top charging coke. The reaction conditions were featured as high temperature, high alkali condition, intense reaction atmosphere and short time. Distribution of porosity in profile, microstructure and slag forming property of ash were analyzed and following conclusions were obtained. After alkali-rich reaction, there were obvious differences between top charging coke and tamping coke in microstructure. The porosity′s unevenness of tamping coke was greater than those of top charging coke, and tamping coke was with less and big pores in out space and inner part was dense with more throughout pores. After phase diagram and microstructure analysis, it could be obtained that ash forming characteristics of top charging coke were better than those of tamping coke, and top charging coke′s pores were blocked more seriously than those of tamping coke. From analysis of tuyere samples, it could be found that calcium content of ash in coke′s pores was small and it should belong to coke′s inherent ash; kalium (wK=28%) was unusually high in coke, so the situation of high alkali was close to real blast furnace reaction condition.     

熔融气化炉内块煤裂解特性的差异化分析

为了研究块煤在熔融气化炉内高温结构演变和降解机制,采用扫描电镜和光学显微镜观察了COREX熔融气化炉风口焦和实验室自制半焦的形貌和显微结构,并结合不同试样的高温反应特性,确定了不同风口焦试样的来源。结果表明,风口焦中兴隆庄块煤形成试样含有较多的中粒和粗粒镶嵌结构,表面呈孔状结构;大同块煤形成试样中类丝炭较多,表面呈层状结构。根据结果提出应考虑灰分对煤焦高温强度的影响,在测量风口焦试样的反应性及反应后强度时应考虑灰分含量进行折算,并确定了以灰分的基准含量为13%进行折算为最佳条件。     

Mathematical Modelling and Experimental Investigation of Coke Reduction of FeO in Slag

Mathematic model development and experimental investigations were carried out for the reduction of FeO in slag by coke. Rate expressions for the reduction limited by the different steps and through different reaction routes were proposed. In the experimental investigation, the FeO reduction was found to be a first order and irreversible reaction; the reduction rate increased with increasing temperature and the FeO content in slag, and decreased with increasing ash content in the coke. Low CO₂/CO ratio in the product gas and preferential reduction of FeO over SiO₂ in slag were observed in the reaction system. The proposed reaction mechanisms were discussed with the observed kinetic phenomena. The reduction of FeO in slag by coke was found most likely to be jointly dominated by the mass transfer of FeO in slag and the chemical reactions at slag‐coke, slag‐gas or slag‐metal interfaces.