著者

Shota Yokokawa Hideya Nakamura Tomotaka Otsu Shuji Ohsaki Satoru Watano Shohei Fujiwara Takahide Higuchi

出版者

The Iron and Steel Institute of Japan

雑誌

ISIJ International (ISSN:09151559)

巻号頁・発行日

pp.ISIJINT-2022-498, (Released:2023-01-19)

参考文献数

31

被引用文献数

3

---

Wet granulation plays an important role in the processing of fine ore powder. Water content is a critical process parameter that determines the granule properties during wet granulation. However, in the ironmaking industry, various types of iron ore powder imported from different regions are blended, quicklime powder is added as a binder, and used as raw materials. Therefore, the physicochemical properties of the raw powders are not always consistent, which makes it difficult to determine the optimum water content. In this study, we present a method to determine the optimum water content using the agitation torque of wet ore powder blended with quicklime. First, we investigated the agitation torque for blending of various types and ratios of ore powders and quicklime. Two types of torque profiles were observed: a unimodal torque profile (Type I) and a torque profile with a plateau region (Type II). From the agitation torque profile, the characteristic water content (

著者

Tomotaka Otsu Hideya Nakamura Shuji Ohsaki Satoru Watano Shohei Fujiwara Takahide Higuchi

出版者

The Iron and Steel Institute of Japan

雑誌

ISIJ International (ISSN:09151559)

巻号頁・発行日

pp.ISIJINT-2022-009, (Released:2022-03-12)

参考文献数

35

被引用文献数

5

---

Wet granulation of iron ore powders is a key process in ironmaking. In wet granulation, it is important to determine the optimum content of water added to the original ore powders. To determine the optimum water content, it is important to understand the saturation state in wet ore powder, which can be done by measuring the agitation torque of the wet powder. This study proposes a methodology for determining the optimum water content of various iron ore powders using the agitation torque of wet ore powders. First, measurement of the agitation torque and wet granulation of various iron ore powders were conducted. By comparing the results, it was found that the optimum water content, which was defined as the minimum water content required to diminish fine particles in the original powder, corresponded to the water content exhibiting the maximum agitation torque, regardless of the original powder. Using the agitation torque at different water contents, the saturation degree S, which is the volume ratio of water to the interparticle voids, was calculated, resulting in a range of 0.999 ≤ S ≤ 1.173 at the optimum water content. This suggests that the state between the funicular and capillary states is a suitable saturation state for the wet granulation of ore powders. Consequently, it was demonstrated that it is possible to determine the optimum water content for wet granulation of various iron ore powders based on the water content exhibiting the maximum agitation torque of wet ore powders.

著者

Naoyuki Takeuchi Yuji Iwami Takahide Higuchi Koichi Nushiro Nobuyuki Oyama Michitaka Sato

出版者

The Iron and Steel Institute of Japan

雑誌

ISIJ International (ISSN:09151559)

巻号頁・発行日

vol.54, no.4, pp.791-800, 2014-04-15 (Released:2014-06-05)

参考文献数

31

被引用文献数

11 16

---

In the recent operation of blast furnace, it is supposed that high gas permeability of burden is important for low RAR and high PCR operation. In this work, sinter quality for improvement in gas permeability of blast furnace was investigated with reduction degradation and under-load-reduction tests. As the results, the reduction degradation of sinter is deteriorated by increasing H2 concentration in the reduction gas under the condition of below 3.8 vol% H2. However, over 3.8 vol% H2, increase of H2 has no effect on the reduction degradation because the diffusion of reduction gas in the sinter is limited. On the other hand, from the under-load-reduction test, there is possibility that increase in H2 concentration of reduction gas and decrease in slag ratio in sinter are effective to improve gas permeability of lower part of blast furnace rather than reducibility of sinter. Due to adoption of these experimental results to a 2-dimentional mathematical simulation model, the precision of pressure drop calculation of blast furnace was improved. It is considered from the evaluation by this model calculation that the RDI, a slag ratio and the slag viscosity as the sinter properties are greatly influence on the permeability of blast furnace.