Abstract Optimum conditions for preparing carbon-containing pellets with a high crushing strength and high reactivity using three kinds of cold-bonded pellets (CPs) prepared by different methods are investigated in this study. The carbon-containing pellets, which have a size fraction suitable for blast furnace are prepared by completely filling the pores in CPs with carbonaceous materials derived from coke oven gas (COG) tar by the vapor deposition (VD) method. A flow-type quartz fixed-bed reactor is used for this method, using a combination of tar pyrolysis at 700 °C and VD at 350 °C. The changing pore size distribution, distribution of the carbonaceous material, and crushing strength of the VD samples are then measured for the prepared composites. The carbonaceous materials derived from COG tar completely fills into the mesopores and macropores of the CPs, which is prepared by using Portland cement (PCB) or Carboxymethyl cellulose (CMC), as the binder, and the aging method in stainless-steel container, with increasing VD treatment time. When PCB is treated by the VD method, the C content and crushing strength tends to increase with increasing VD treatment time, and reached 16 wt%-dry and 45 daN, respectively, until 60 min; these values are comparable to the strength of metallurgical-coke with DI1506 = 87.1. Additionally, carbonaceous materials are uniformly deposited in the particles inside. The changes in the reduction behavior and crushing strength of the prepared VD sample under various heat conditions (simulation-values in experimental-blast furnaces in COURSE50 project). The reduction extent of the VD samples prepared from PCB reaches up to 30–40% at 850 °C. These rates increase above 850 °C and attain a value >95% until 950 °C irrespective of the heating and atmospheric conditions. Fe2O3 and Fe3O4 in the VD samples are reduced to FeO and/or α-Fe until 850 °C under any condition used, while FeO is completely reduced to α-Fe by 950 °C. The cold crushing strength of VD samples is maintained up to 850 °C. Although this value drastically decreases at 900 °C, which is the temperature at which α-Fe formation occurred, there is no decrease in strength for the reduction of Fe2O3 to Fe3O4, which has been observed reduction disintegration occurs in a conventional blast furnace.

中文翻译：

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焦油气相沉积大粒径冷结球团含碳球团模拟试验高炉热处理强度及还原反应性研究

摘要 本研究研究了使用三种不同方法制备的冷粘合球团（CPs）制备高抗碎强度和高反应性含碳球团的最佳条件。通过气相沉积 (VD) 方法，用源自焦炉煤气 (COG) 焦油的含碳材料完全填充 CP 中的孔，制备具有适合高炉的粒度分数的含碳球团。该方法使用流动型石英固定床反应器，结合使用 700 °C 的焦油热解和 350 °C 的 VD。然后测量制备的复合材料的变化的孔径分布、含碳材料的分布和 VD 样品的抗压强度。以硅酸盐水泥（PCB）或羧甲基纤维素（CMC）为结合剂，在不锈钢容器中陈化方法制备的焦炭焦油衍生的碳质材料完全填满了CPs的中孔和大孔中。增加 VD 治疗时间。VD法处理PCB时，C含量和抗压强度随着VD处理时间的增加而增加，分别达到16 wt%-dry和45 daN，直至60 min；这些值与 DI1506 = 87.1 的冶金焦强度相当。此外，碳质材料均匀地沉积在颗粒内部。制备的 VD 样品在各种加热条件下的还原行为和抗碎强度的变化（COURSE50 项目中实验高炉的模拟值）。由 PCB 制备的 VD 样品在 850°C 下的还原程度高达 30-40%。无论加热和大气条件如何，这些速率在 850 °C 以上都会增加，并在 950 °C 之前达到 >95% 的值。在任何使用的条件下，VD 样品中的 Fe2O3 和 Fe3O4 在 850°C 之前都被还原为 FeO 和/或 α-Fe，而 FeO 在 950°C 时被完全还原为 α-Fe。VD 样品的冷抗压强度可保持高达 850 °C。尽管该值在 900 °C（发生 α-Fe 形成的温度）时急剧下降，但将 Fe2O3 还原为 Fe3O4 的强度并没有降低，这在传统高炉中会发生还原分解。95% 直到 950 °C，与加热和大气条件无关。在任何使用的条件下，VD 样品中的 Fe2O3 和 Fe3O4 在 850°C 之前都被还原为 FeO 和/或 α-Fe，而 FeO 在 950°C 时被完全还原为 α-Fe。VD 样品的冷抗压强度可保持高达 850 °C。尽管该值在 900 °C（发生 α-Fe 形成的温度）时急剧下降，但将 Fe2O3 还原为 Fe3O4 的强度并没有降低，这在传统高炉中会发生还原分解。95% 直到 950 °C，与加热和大气条件无关。在任何使用的条件下，VD 样品中的 Fe2O3 和 Fe3O4 在 850°C 之前都被还原为 FeO 和/或 α-Fe，而 FeO 在 950°C 时被完全还原为 α-Fe。VD 样品的冷抗压强度可保持高达 850 °C。尽管该值在 900 °C（发生 α-Fe 形成的温度）时急剧下降，但将 Fe2O3 还原为 Fe3O4 的强度并没有降低，这在传统高炉中会发生还原分解。