含碳球团低温熔分过程中硫的行为

 根据低配碳比含碳球团还原低温熔分制备粒铁的技术思想,对含碳球团还原熔分过程中硫的分配及硫的行为进行了试验研究。结果表明,影响产品铁粒中硫质量分数的主要因素为碳质垫料、球团原料中硫量以及熔分后铁粒在炉内的停留时间。为了降低铁粒中硫质量分数,应尽量限制煤粉、铁矿带入的硫量。要选择硫量较低的碳质垫料,尽量缩短熔分后铁粒在炉内停留时间。垫料中混和适量的固硫剂有利于降低铁粒中硫质量分数。球团中添加CaO未见有脱硫作用,铁粒中硫质量分数反而稍有增加。球团中配碳比的增加会导致含碳球团中煤粉带入的硫量的增加,因此配碳比的增加会稍微提高铁粒中硫质量分数。     

硼铁精矿含碳球团还原熔分同步脱硫

以硼铁精矿、还原剂和添加剂为原料制成含碳球团,经高温还原熔分得到珠铁。为了实现珠铁降硫,在实验室条件下系统研究了配碳量(C/O摩尔比)、还原剂种类、熔融保持时间、添加剂等因素对脱硫效果的影响。试验结果表明:当C/O从1.0增加至1.4时,珠铁中硫含量变化不大,以烟煤做还原剂时珠铁中的硫含量较用无烟煤时低;随着熔融保持时间的延长,珠铁中硫含量呈降低趋势;CaO可显著降低珠铁中硫含量,5%CaO时珠铁中硫含量降低至0.046%,但随着CaO配比增加,球团熔分逐渐变得困难,熔分渣中残余金属铁含量逐渐增加,造成铁的收得率降低;Na2CO3同样可降低珠铁中硫含量,当配入6%Na2CO3时,球团熔分效果很差,此时珠铁中硫含量为0.084%,随着Na2CO3配比的增加,铁的收得率同样逐渐降低。     

关于含碳球团生产珠铁的硫含量控制试验研究

通过对以铁精粉、煤粉、石灰石及少量添加剂为主要原料的含碳球团进行还原试验,研究了碱度( CaO/SiO2)、反应时间、加热温度、添加剂及配碳比(C/O)等不同因素对于含碳球团还原熔分及珠铁中硫含量的影响,并分析了硫元素的分配情况.试验及分析结果表明:碱度、配碳比和反应时间对于珠铁中硫含量的影响较大,而对于碱度较高的含碳...     

高铝高硫低品位铁矿粉还原熔分制备珠铁

 基于转底炉珠铁工艺,以一种高铝高硫低品位铁矿粉和无烟煤为原料,在实验室条件下进行了还原熔分试验研究,考察了温度、配碳量、碱度和添加剂对高铝铁矿含碳球团还原熔分行为的影响,并分析了碱度和添加剂对珠铁中硫质量分数的影响。试验结果表明,温度为1 350～1 450 ℃时,空白球团熔分效果较差,金属铁渗碳量较低;提高配碳量,金属铁渗碳量略有增加,但熔分效果仍较差;碱度增加会促进球团还原,1 450 ℃时,碱度为0.6、0.8、1.0、1.2的球团可以实现渣铁良好分离,珠铁中硫质量分数逐渐降低,碱度为1.2时降低较明显;Na2CO3配比增加,球团熔分也会逐渐变差,1 450 ℃时球团基本均可以熔分,珠铁中的硫质量分数逐渐降低,但脱硫效果不明显;当碱度为1.2、Na2CO3配加为8%、CaF2配加为4%时,球团可以在1 450 ℃下良好熔分,脱硫效果显著,珠铁中硫质量分数为0.085%,脱硫率达到96.5%,所得珠铁基本满足炼钢要求。     

煤基铁精粉生产低硫珠铁试验研究

对采用铁精粉、煤粉和石灰石为主要原料,配加CaF2所制成的含碳球团,在不同试验方案下进行还原试验研究,分析珠铁的生产过程和渣铁的组织成分,计算硫元素的分配情况.试验结果表明:采用合理的试验方案,能使含碳球团在27 min内还原熔分效果良好,并得到含硫量较低的珠铁;所得珠铁的内部组织结构主要由珠光体和渗碳体组成;渣中以Ca2Mg(Si2O7)和Ca3Mg(SiO4)2为主,其它成分很少;增加CaF2配入量,使得进入珠铁中的硫元素减少,进入渣中的硫元素增多;提高加热温度,使得进入珠铁中的硫元素减少,进入空气中的硫元素增多.     

硫在含碳球团内的转化行为

为了研究含碳球团还原产品中硫含量过高的问题和出路,笔者借鉴高温法定硫的原理,设计了一套分析测定装置,首次系统地研究了铁精矿配加烟煤、无烟煤和生石灰等原料之后的含碳球团在不同温度、时间条件下硫的分解转化行为,得出了煤种、CaO含量、温度和时间等条件对产品硫含量的影响趋势,分析揭示了试验现象与脱硫反应之间的规律,并对含碳球团的工艺选择与环保的关系进行了相应的论述.     

高炉铁水中硫加速炉缸炭砖侵蚀机理及对策

为了延缓炉缸炭砖侵蚀，分析了炉缸铁水硫含量变化趋势，研究了硫元素加速炉缸炭砖侵蚀机理，提出了现代大型高炉脱硫技术措施。结果表明：高炉-铁水预处理联合脱硫、使用高比例球团是炉缸铁水硫含量升高的主要原因；炉缸炭砖与碳含量欠饱和的铁水接触是炭砖侵蚀的直接原因，硫含量升高使铁水表面张力下降、黏度下降，提高了界面反应速率，增大了铁水中碳的传质系数，加速了炭砖侵蚀。在低渣比条件下，控制炉渣碱度在1.12～1.18,MgO含量在9%～12%,Al₂O₃含量在13.5%～15.5%,并提高铁水中碳、硅、磷元素含量，降低锰、钛元素含量，采用控制炉渣成分和铁水成分的协同脱硫技术，是现代大型高炉脱硫的有效措施。     

酸洗污泥含碳球团渣铁浴处理过程中硫的分布

 不锈钢硫酸酸洗过程产生大量的酸洗污泥,其成分中含有高含量的CaSO₄以及铁、铬等有价金属。活性炭经过多次吸附会丧失活性,但仍保持还原性能。由酸泥、活性炭混匀并焙烧制成含碳球团,在高炉过程渣铁混出时将该球团掷入渣铁熔池进行还原处理,酸泥中的Fe、Cr被还原后进入铁水,其他物质进入高炉渣,实现酸洗污泥的去毒、消纳和资源化利用的目标。鉴于硫酸酸洗后的污泥中含有大量硫元素,重点探讨以上工艺技术中球团焙烧温度、配碳量及球团在熔炼过程的添加量等因素对硫在各相中分配行为的影响趋势,主要采取热力学理论计算、实验室试验等研究手段。结果表明,球团C/S物质的量比为2、球团焙烧温度为400 ℃时,向渣铁浴熔池中加入1%占比的球团可控制渣铁浴终点铁水硫质量分数w([S_f])为0.010%左右,此时熔渣固硫率可达到50%;球团C/S物质的量比为0.5、球团焙烧温度为400 ℃或800 ℃时,向渣铁浴熔池中加入3%占比的球团,也可降低渣铁浴终点铁水硫质量分数,w([S_f])为0.01%左右,且酸泥中Fe/Cr回收率达88.27%,但熔渣固硫率较低。本研究说明,利用渣铁浴工艺处理酸洗污泥,通过合理调控试验参数,可有效控制终点铁水硫含量至较低水平,达到深脱硫效果,同时Fe/Cr具有较高的回收效率,渣铁浴前后炉渣成分变化极小,不会影响高炉渣安全性及后续利用,具有较高的环境和经济效益。     

Fastmet工艺评述

介绍了Ｆａｓｔｍｅｔ工艺及发展状况，并对工艺特点和指标进行了分析。使用冷固结含碳球团和转底炉使该工艺可直接采用粉矿和提高生产效率，但因硫含量高、铁品位低而产品质量较差。不过投资和生产成本与传统工艺比较却占有较大优势。     

铁水罐处理尘泥含碳球团技术研究与实践

将钢铁企业的各类尘泥通过合理搭配制成含碳球团,利用铁水罐进行高温铁浴还原加以回收利用。针对处理过程中球团不能充分熔化、渣铁分离困难等问题,在实验室进行了改进性模拟研究,重点分析了配加CaF2、CaO等熔剂对反应后铁中硫含量和铁收得率的影响。在此基础上进行了工业试验,结果表明,改进后的尘泥含碳球团在铁水罐中熔化良好,反应完全,平均铁收得率达到92.5%,实现了尘泥资源的高效回收利用。     

Reduction Behaviour of Iron Ore–Coal Composite Pellets in Rotary Hearth Furnace (RHF): Effect of Pellet Shape,Size, and Bed Packing Material

Reduction of iron ore–coal composite pellets in multi-layers at rotary hearth furnace (RHF) is limited by heat and mass transfer. Effect of various parameters like pellet shape, size, and bed packing material that are supposed to influence the heat and mass transfer in the pellet bed, have been investigated, on the reduction behaviour of iron ore–coal composite pellets at 1250 °C for 20 min in a laboratory scale RHF. Reduced pellets have been characterised through weight loss measurement, estimation of shrinkage, porosity, and qualitative, quantitative phase analysis by XRD. A significant difference in the degree of reduction is observed layer-wise in the pellet bed with the variation in pellet shape and size. Pellet bed without any packing material or packed with coal have demonstrated higher degrees of reduction compared to the pellet bed packed with graphite and sand.     

台车连续炉直接还原法

开发了一种在台车连续炉中实现铁矿直接还原的方法。台车连续炉的炉膛是直条形,炉底由若干个台车组成。含碳球团料层铺在台车上,通过炉膛时进行还原焙烧。为了得到高金属化率,在料层表面覆盖薄焦炭层保护。此方法已经成功地用于唐钢石人沟铁矿。生产线所用的炉子长70 m,宽2 8 m。炉底由26 个台车组成。用这种方法生产的海绵铁产品成分如下:金属化率大于92%,全铁约90%,硫小于0 08%。一座炉子的产量为5 t/h,总煤耗低于700 kg/t。和转底炉比较,台车连续炉的优点是:结构简单,供热点少,台车维修方便,主要缺点是台车运转速度不能太快,焙烧时间较长。     

Effect of CaO on the reduction behaviour of iron ore–coal composite pellets in multi-layer bed rotary hearth furnace

The effect of CaO on the reduction behaviour of iron ore–coal composite pellets has been studied in a laboratory scale multi-layer bed rotary hearth furnace at 1250°C for 20?min. Reduced pellets have been characterised through weight loss, porosity measurement, phase analysis by XRD, and morphology study by SEM. The addition of CaO to the composite pellets showed different effects at different carbon levels. For higher carbon-containing pellets (C/Fe₂O₃ molar ratio at the upper stoichiometric level of 3), the addition of CaO increased the extent of reduction for all three layers significantly up to a certain limit (4?wt-%); and thereafter the degree of reduction is decreased with a further increase in CaO percentage in the pellets. For low carbon-containing pellets (C/Fe₂O₃ molar ratio of 1.66), the addition of CaO to the pellets did not show any beneficial effect.     

A Computational Study on the Reduction Behavior of Iron Ore/Carbon Composite Pellets in Both Single and Multi-layer Bed Rotary Hearth Furnace

Metallurgical and Materials Transactions B - A phenomenological model for the reduction of iron ore/carbon composite pellets in a multi-layer bed rotary hearth furnace has been developed. A single...     

铁矿直接还原用台车连续炉

介绍一种用于铁矿直接还原的台车连续炉，含碳球团料层铺在台车上并通过炉膛进行焙烧和还原。此炉子已经成功地用于铁精矿粉还原焙烧，所得到的海绵铁产品的金属化率大于92％，全铁约90％。和转底炉比较，台车连续炉的优点是结构简单，供热点少，台车维修方便；主要缺点是台车运转速度不能太快，焙烧时间较长。     

高炉低硅铁冶炼技术应用

湖北新冶钢二炼铁厂从降低生铁成本出发，生产低硅生铁。采取了提高原料和烧结矿质量，严格控制并稳定炉缸温度，富氧、喷煤、大风量、大料批（每批14．1t）、正分装、抑制边缘、发展中心的操作方针，使顶压升高，一氧化碳压力增大，一氧化碳利用率提高，燃料比和生铁硅含量降低。生铁含硅量逐步降到0．3％左右，高炉主要技术经济指标明显改善。     

含碳球团的还原熔分行为

通过高温电阻炉对含碳球团还原熔分的行为进行热态模拟研究,考察温度、配碳比、化学成分等因素对球团还原熔分的影响程度.结果表明,温度、配碳比和球团传热方向上的尺寸是控制球团还原熔分的关键;化学成分对还原速率影响不明显,但是通过改变渣的组成可对渣铁熔分起促进或抑制作用.     

Investigation of Reduction and Smelting Mechanism in the Hi‐QIP Process

A new coal‐based reduction and smelting process for production of high quality iron pebbles in a rotary hearth furnace (Hi‐QIP Process) was developed. The reduction, carburization, smelting, and separating mechanism of the Hi‐QIP process were investigated. The experiments were carried out in a graphite heater furnace under rapidly heating up to 1773 K. A mixture of coal and ore produced molten metal and slag, which were held on the coal and did not come into contact with the refractory located under the coal layer. It is confirmed that the reduction of wettability between the iron and slag promotes the separation of them, when the content of FeO slag decreases. High productivity of the process is expected when using iron ore with small particle diameter and low gangue content. Favourable operating results were obtained in a pilot test using a rotary hearth furnace with a diameter of 7 m and a width of 1.5 m. This test demonstrated the possibility of continuous production of iron pebbles with high productivity (15t‐iron/d).     

Smelting Reduction of Iron Ore‐Coal Composite Pellets

Smelting reduction of iron ore‐coal composite pellets has been carried out in an induction furnace. The pellets, tied with tungsten wire, were immersed into the liquid metal bath. The experiments were carried out in the temperature range of 1713 K to 1733 K. For 16‐18 mm diameter pellets, it was observed that (i) the time required for complete dissolution in liquid metal bath is 83‐90 seconds, (ii) the fraction of reduction for 40 seconds of immersion varied from 0.68‐0.87 for Jharia coal pellets and 0.73‐0.92 for Bhilai coal pellets, and (iii) the fraction of reduction increases with decreasing Fe/C ratio and increasing immersion period. X‐ray diffraction (XRD) of reduced pellets showed that the reduction occurred topochemically. Scanning electron microscopic (SEM) examination of partially reduced pellets evinced the structural changes in pellets. The present investigation aims to assess the effect of Fe/C ratio in pellet, volatile matter in coal, and time of pellet immersion into liquid metal bath on reduction of iron ore‐coal composite pellets.