Fundamental Study on New Method of Reducing Iron Ore-Coal Pellet in Cocurrent Shaft Furnace

Based on the laboratory experiment of reducing iron ore-coal pellet in oxidizing atmosphere,a new self-heating reduction method of iron ore-coal pellet in the cocurrent shaft furnace(CSF) has been developed.In this process,the pellets and preheated oxygen-enriched air enter the shaft furnace through its top and descend cocurrently in the furnace.Most of the heat required for rising temperature and endothermic reduction of descending pellets is provided by the way that the descending air burns the volatile from pellets and CO from the reduction of iron oxide in pellets.The reduced pellets and high temperature gas are discharged from the lower part.The sensible heat and chemical energy of the off-gas are used to heat the oxygen-enriched air in stove.This process is applicable to the direct reduction of iron pellets and prereduction of iron pellets in smelting reduction with iron bath.

Application of carbon composite iron ore hot briquette to innovative ironmaking process

As a new type of ironmaking raw materials,carbon composite iron ore hot briquette(CCB) is the product of fine iron ore and fine coal by hot briquetting process.On basis of experimental research on the manufacturing and metallurgical properties of CCB,this study focused on the application of CCB to blast furnace ironmaking and newly-developed shaft furnace smelting reduction processes.Firstly,the metallurgical properties of CCB are experimentally tested and compared with the common iron-bearing burdens.Then,the effects of charging CCB on blast furnace operation are numerically analyzed by means of multi-fluid blast furnace model,and the flowchart and pilot test of CCB-Shaft furnace smelting reduction process are briefly introduced.

微波焙烧赤泥-稻壳压块回收铁

本文提出了一种利用微波体相加热还原焙烧赤泥−稻壳压块并从中回收铁的新方法,研究了进料方式、生物质用量、焙烧温度和时间等主要工艺参数对铁回收的影响。结果表明:在稻壳赤泥比为3、焙烧温度为1000℃、焙烧时间为20 min的优化条件下,得到铁品位为60.1%、回收率为86.3%的铁精矿。利用X射线衍射和X射线荧光光谱分析研究了赤泥中铁氧化物还原过程的机理,赤泥中的含铁矿物被还原成Fe和FeO等磁性物质。

Gas release characteristics during carbonization of iron coke hot briquette and influence of heating rate

The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the release rate of H2 and promote the production of CO and CO_(2).In addition,when the heating rate increases from 3 to 7℃/min,the release rates of CH4 and H2 increase,while the release rates of CO and CO_(2) first increase and then decrease.The carbonization process of ICHB was segmented,and corresponding kinetic analysis was carried out.The results show that the activation energy of StageⅡand StageⅣis higher in the carbonization process of ICHB,and the active pyrolysis of coal and the reduction of iron ore occur in these two stages.In addition,the effect of heating rate on the kinetic parameters of ICHB carbonization process was investigated.It was found that when the heating rate increased,the reaction activation energy of StageⅣdecreased first and then increased,which was consistent with the release law of CO and CO_(2).The analysis showed that the increase in heating rate leads to more reactions at higher temperatures,resulting in an increase in the release rate of some gases.In addition,thermal hysteresis can also cause some processes to fail to fully react at the end of heating.It is also found that the apparent activation energy and preexponential factor have kinetic compensation effect during the car-bonization of ICHB.

Non-isothermal reduction process analysis of iron-bearing burden with charging iron coke hot briquette under simulated blast furnace conditions

Highly reactive iron coke hot briquette(ICHB)prepared by carbonizing the agglomerate of iron-bearing substance and blended coals is regarded as an alternative fuel to mitigate carbon emission and energy consumption of blast furnace.Simultaneously,the reduction process of iron-bearing burden is extremely crucial for blast furnace smelting.The effects of ICHB on the non-isothermal reduction process of iron-bearing burden with different reduction properties were thus experimentally studied under the conditions of simulated blast furnace lump zone(below 1100°C),and the related mechanism was discussed and analyzed.The results showed that the non-isothermal reduction process of iron-bearing burden is promoted by adding ICHB.As the charging ratio of ICHB is increased from 0%to 30%,the reduction degree of pellet is increased from 22.91%to 36.62%,but the increased amplitude is leveled off.Furthermore,the reduction degree of sinter is raised from 35.10%to 93.33%.It is also indicated that the promotion effect of ICHB on the non-isothermal reduction of iron-bearing burden depends on the reduction property of burden.Compared with the burden with poor reduction performance(such as pellet 1),the promotion is more significant for the burden with good reduction property(such as sinter 1)since the reduction reaction of iron oxide in iron-bearing burden and the gasification of carbon in ICHB are remarkably reinforced each other.The practical application of ICHB in blast furnace should be utilized with highly reductive iron-bearing burden.

热压含碳球团自还原过程限制性环节的实验研究

在传热条件一定的前提下,于900～1150℃反应温度范围内进行了热压含碳球团的自还原实验.通过分析热压含碳球团还原失重和产物气体的变化规律,阐述了热压含碳球团的自还原机理.结果表明,热压含碳球团的自还原可用多孔物料反应模型进行描述.整个过程分为两个阶段,第一阶段还原速率明显大于第二阶段.在本研究条件下,热压含碳球团自还原过程两个阶段的限制性环节均为气体通过还原产物层的内扩散.

热压含碳球团冷态强度的实验研究

重点考察了煤种及热压工艺参数对热压含碳球团冷态强度的影响，并探讨了热压含碳球团获得高强度的机理．研究表明，煤种、配煤量、热压温度、配煤粒度及热压压力等热压工艺参数对热压含碳球团强度具有显著影响，其中热压温度是影响冷态强度最重要的因素．热压工艺利用煤的热塑性保证煤矿颗粒充分接触，增大粘结面积，从而使热压含碳球团的强度高于冷固结含碳球团．从冷态强度角度出发，以鹤岗烟煤为原料生产热压含碳球团的适宜工艺参数为配煤量25％～35％，热压温度450℃，配煤粒度〈90μm，热压压力不低于35MPa．

配碳比对热压含碳球团软熔滴落性能的影响

在碱度固定为1.20的条件下,系统研究了配碳比n(FC)/n(O)对热压含碳球团软熔滴落性能的影响,并进行了理论分析.研究表明,配碳比对软化区间、熔化区间、滴落率等软熔滴落性能参数有显著的影响.随着配碳比增加,软化区间t40～t4先变窄后加宽,在配碳比为1.00时最窄,降至348℃;熔化区间tD～tS也先变窄而后加宽,当配碳比为1.00时最窄,降至46℃;滴落率先增加后降低,在配碳比为1.08时滴落率最高,达到24.66%.从软熔滴落性能角度综合考虑,实际生产热压含碳球团时其配碳比宜定在1.00左右.

低品位难选铁矿还原焙烧－磁选生产金属化团块的研究

本文结合我国铁矿资源多为低品位难选铁矿的特点，通过试验研究，提出采用直接还原－细磨磁选生产铁品位高、质量稳定的金属化团块，作为电炉炼钢的生产原料。

工艺参数对热压铁焦抗压强度的影响

热压铁焦是一种新型含碳复合炉料,高炉使用铁焦有助于降低热空区温度、减少CO_2排放.研究了工艺参数对热压铁焦抗压强度的影响,并分析其作用机理.研究结果表明,在一定范围内,铁焦抗压强度随着铁矿粉配比增加先增加后降低,在矿粉配比15%时取得较大值3 490.89 N;随着烟煤配比的增加而提高;随着热压温度的提高而提高,在热压温度350℃时取得较大值4 305.50 N;随着炭化温度的提高先降低后提高;随着炭化时间的增加先提高后降低,在炭化时间4 h时取得较大值3 518.80 N.从抗压强度角度考虑,热压铁焦合适的制备工艺参数为10%~15%铁矿粉,60%~70%烟煤,热压温度300~350℃,炭化温度1 000~1 100℃,炭化时间2~4 h.

热压铁焦对高炉综合炉料熔滴性能的影响

利用荷重还原软化熔融滴落实验研究了热压铁焦添加量对高炉综合炉料滴落性能的影响.研究结果表明,随着热压铁焦配比的增加,综合炉料软化区间逐渐加宽,从206.3℃增加到218.9℃;熔化区间逐渐收窄,从171.1℃降低到124.8℃,软熔带逐渐变窄且位置下移;综合炉料滴落压差下降,滴落率先升高后降低,在热压铁焦配比为30%时达到较高值40.58%;综合炉料熔滴总特征值逐渐降低,料层透气性改善.一定量的热压铁焦有助于改善综合炉料熔滴性能,其适宜添加量在30%左右.

高炉炼铁新技术的数学模拟研究

利用多流体数学模型对革新高炉炼铁技术进行了数学模拟,分析评价了革新操作对炉内现象及高炉生产指标的影响.这些革新炼铁技术包括高炉喷吹含氢物质实现富氢还原,高炉使用热压含碳球团实现低温炼铁,以及高炉炉顶煤气喷吹加强C和H的利用.多流体模型的模拟解析表明,高炉超高效率操作(高产、低能耗和低CO2排放)可通过这些革新技术的实际应用来实现.

铁矿热压含碳球团生产工艺开发

重点考察了煤种及热压工艺参数对热压含碳球团冷态强度的影响,并探讨了热压含碳球团获得高强度的机理。试验研究表明,煤种特性、配煤量、热压温度、煤的粒度及热压压力等热压参数对热压含碳球团强度具有显著影响,合理的热压工艺要充分利用煤的热塑性,保证煤、矿颗粒充分接触,增大粘结面积以提高热压含碳球团强度。通过研究,得出了适宜的热压含碳球团生产工艺参数。

用BSR法将宝钢高锌含铁尘泥资源化的试验研究

介绍了利用转炉红热钢渣处理宝钢高锌含铁尘泥冷团结自还原球团的ＢＳＲ法工业试验研究。试验结果表明，钢渣显热可以有效地将高锌含铁尘泥脱锌并熔融还原成可代替废钢使用的粒铁产品。由于不需要专门的熔炼设备，ＢＳＲ法投资、成本较低，是一种很有竞争力的回收钢铁厂尘泥的新技术。

热压含碳球团高温冶金性能的实验研究

热压含碳球团是一种利用煤热塑性提高强度的新型炼铁原料。在实验室条件下,对碱度1.2和FC/O比1.0的未热处理和热处理热压含碳球团,分别检验其低温还原粉化、还原膨胀、还原冷却后强度等高温特性,并与其他炼铁原料进行合理对比。实验结果表明,热压含碳球团的高温冶金性能优于普通球团矿或烧结矿,适用于炼铁生产。

MgO对Fe_2O_3压团还原过程铁氧化物晶格结构的影响

以纯试剂为原料,采用"压团-焙烧-还原"的方法,研究了MgO对Fe_2O_3压团在还原不同阶段铁氧化物晶格结构的影响,为探索球团矿还原膨胀机理、理解铁氧化物还原反应机制提供理论基础。研究结果表明:在压团焙烧阶段,晶格常数a,b的变化是由于溶质原子周围点阵膨胀所致,而晶格常数c的变化是因为氧的减小;在Fe_2O_3还原到Fe_3O_4阶段,Mg^(2+)能同时固溶在两种铁氧化物中,稳定晶格,阻碍了还原的进行;在Fe_2O_3还原到FexO阶段,随着MgO添加量的增加,FexO晶胞参数随之减小,符合Vegard线性定律;Fe_2O_3还原到Fe阶段,MgO对Fe的晶胞参数无明显影响。最终探明了MgO在Fe_2O_3压团还原过程中的行为规律。

煤的性质对铁矿煤压块反应过程的影响

在升温条件下进行了不同性质的煤制成的铁矿—煤压块反应实验。结果表明 :反应初期主要是挥发分的析出 ,在还原过程中 ,铁矿—无烟煤压块中挥发分先将铁氧化物还原至 Fe O,然后碳将 Fe O还原到 Fe。铁矿—烟煤压块中挥发分和碳能够连续将铁氧化物还原到 Fe,无烟煤和烟煤混合制成的铁矿—混合煤压块中先是烟煤中的碳将铁氧化物部分还原至 Fe,然后无烟煤中的碳将剩余的 Fe O还原到

内配煤团块高温自还原特性研究

通过对内配煤团块高温自还原过程中的直接还原和间接还原反应的研究,定义了内配煤团块自还原反应的间接还原指数(α),并建立了间接还原指数(α)与直接还原度(γd)之间的关系.结果表明,内配煤团块在高温下的自还原反应并不是100%的直接还原反应.内配煤团块自还原反应的直接还原度随团块内脉石(或渣相)含量升高而降低;直接还原度越高,还原产物的残碳含量也就越低.内配煤团块自还原反应氧化铁的还原率随含铁品位升高而增加.内配煤团块自还原过程中的气化脱硫率可达到25%~28%.

鲕状赤铁矿深度还原过程中铁颗粒粒度和形貌特征分析

为研究鲕状赤铁矿和煤粉的混合球团矿经深度还原后铁颗粒的粒度和形貌特征,通过压块的方式模拟球团矿在高温下进行深度还原反应,并采用扫描电子显微镜(SEM)和工艺矿物学参数自动测试系统(BPMA)考察不同温度和时间下煤基球团矿经深度还原后金属铁颗粒的平均粒径、粒度分布和镜下形貌等特征变化。研究结果表明:随着还原温度升高或还原时间延长,铁颗粒粒径不断增大,且还原温度对铁颗粒长大的影响更显著;在不同还原条件下,粒度区间前20%中的铁颗粒数量占总体数量的60%~85%;铁颗粒的长大过程主要包括单个球形铁颗粒的析出与粗化,颗粒之间链接形成堆积铁颗粒集团并逐渐熔合均一化,最终生成稳定的大颗粒。

热压含碳球团制备及性能

采用烟煤加热时产生的胶质体作为黏结剂来压制热压含碳球团。根据胶质体的最高流动度和热稳定性,用单一煤种压制热压球团时,肥煤是最好的黏结煤。相对于同成型条件下的冷压含碳球团,热压含碳球团强度更高,相同还原条件下的反应速度更快。