Fundamental Study on Carbon Composite Iron Ore Hot Briquette Used as Blast Furnace Burden

Carbon composite iron ore hot briquette (CCB) is the product of fine iron ore and fine coal by hot briquetting process, which attracts more and more attention as a new type of ironmaking raw materials aiming to improve the operation efficiency and reduce the coke consumption of blast furnace. This paper is devoted to experimental study on metallurgical properties of CCB and numerical simulation of the BF operation with CCB charging. At first, the metallurgical properties of CCB, including cold crushing strength, RDI, RSI, reducibility, high temperature strength, and softening and dripping are experimentally tested and compared with the common burdens, which revealed that the CCB possesses the required metallurgical properties and is suitable to use as the blast furnace burden. Then, the effects of charging CCB on the dripping properties of comprehensive burdens are elucidated based on the experiments under simulated blast furnace conditions. The results showed that the maximum charging ratio of CCB in the iron burdens is 40%–50% for achieving appropriate dripping properties of the mixed burdens. Finally, a multi‐fluid blast furnace model is used to simulate BF operation with CCB charging. According to model simulations, charging CCB will cause the temperature level to decreases in the furnace and the location of the cohesive zone shifts downward. On the other hand, the productivity tends to increase while coke rate and total reducing agent rate decrease, the heat efficiency improves remarkably and the operation performance of BF is effectively enhanced.     

碱度对热压含碳球团软熔滴落性能的影响

热压含碳球团是一种利用煤的热塑性提高冶金性能的新型炼铁原料,具有还原速度快、高温强度高、原料适应性强等优点。在固定碳氧比n(FC)/n(O)为1.00的条件下,通过改变热压含碳球团碱度,系统研究了碱度对热压含碳球团软熔滴落性能的影响。研究表明:碱度对软化区间、熔化区间、滴落率等软熔滴落性能参数有显著的影响。随着碱度的增加,软化区间t40-t4先变窄后加宽,在碱度为1.40时最窄,降至331℃;熔化区间tD-tS先缓慢变窄后急剧加宽,在碱度为1.00时最窄,降至47℃;滴落率先增加后降低,在碱度为1.20时滴落率最高,达到22.22%。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适宜的碱度范围为1.00~1.20。     

高炉炉料配加热压含碳球团软熔滴落性能的试验研究

 以常用的炼铁原料为基础,系统研究了配加不同比例的热压含碳球团对高炉炉料的软熔滴落性能的影响,并进行了理论分析。研究表明,配加热压含碳球团对高炉综合炉料的软化区间、熔化区间、滴落率和透气性等软熔滴落性能参数有显著的影响。随着热压含碳球团配比的增加,软化区间t40-t4逐渐变宽;熔化区间tD-tS逐渐变窄,熔化开始温度tS逐渐升高,滴落温度tD逐渐降低;滴落率先增加后降低,当配比为40%时,滴落率最高,为6710%;最高压差先下降后升高,但在配加热压含碳球团条件下,炉料的最高压差都有所降低。从综合炉料的软熔滴落性能综合考虑,高炉炉料配加热压含碳球团的适宜配比应为40%~50%。     

反应气氛和温度对热压含碳球团还原反应进程的影响

热压含碳球团是利用煤的热塑性而将铁矿粉和煤粉热压成型的一种新型优质炼铁原料.还原性是炉料主要冶金性能之一,而反应气氛和温度对热压含碳球团还原反应进程有重要的影响.通过还原失重试验,重点研究了反应气氛和温度对热压含碳球团还原反应进程的影响.研究表明,热压含碳球团整个还原反应进程可分为两个阶段:第一阶段还原速率明显大于第二...     

Some Studies to Establish the Reaction Mechanism for the Reduction of Iron Ore‐Graphite Composite Pellets in a Packed Bed Reactor

In this article an attempt has been made to propose a reaction mechanism for the reduction of iron ore‐graphite composite pellets in a packed bed reactor through experiments and mathematical models developed by the authors previously, along with some new supportive experimental data. A tailor made thermo‐gravimetric setup with a provision of packed bed has been developed to carry out isothermal experiments at elevated temperature and in controlled atmosphere. A kinetic model that calculates the evolution of various phases of iron oxides and a thermal model that calculates the temperature at the surface and centre of the cylindrical packed bed have been used along with experimental data under different operating conditions to formulate the reaction mechanism. It is proposed that reduction of iron ore‐graphite composite pellets in packed bed is initially heat transfer controlled and become mass transfer controlled at the later stage of reduction. The role of heat and mass transfer has been ascertained by observing the effect of C/Fe₂O₃ molar ratios, size of pellets, and CO gas in reactive atmosphere on the extent of reduction and the predicted temperature gradient, carbon consumption rate within the packed bed during the course of reduction.