Search

The blast furnace tuyere is a crucial component for blast furnace production. The frequent damage of the copper tuyere impedes the smooth operation of the blast furnace. Welding a wear‐resistant layer on the tuyere can extend its service life, but it still falls short of the expectation in a large blast furnace. In this article, it is aimed to elucidate the erosion mechanism of the wear‐resistant layer. A scanning electron microscope, an energy dispersive spectrometer, and an optical microscope are employed to examine the morphology, composition, and metallographic structure of the samples obtained from a 5800 m3 blast furnace tuyere in China, as well as to calculate the frequency of daily slag crust shedding from cooling staves. The results indicate that the main cause of the erosion of the wear‐resistant layer is the shedding of slag crust due to the temperature fluctuation of the cooling staves. Finally, the erosion mechanism of the wear‐resistant layer is proposed. It is suggested that the formation and propagation of cracks caused by erosion of slag and hot metal are the primary failure mode of the wear‐resistant layer. [ABSTRACT FROM AUTHOR]

The optimized blast furnace design is the prerequisite for low-carbon smelting. The salamander depth and bosh angle are the key parameters, which determine the blast furnace longevity. In this paper, the physical and mathematical force model of deadman and cooling stave was established. The relationship between operating parameters and the salamander depth, as well as bosh angle, was analysed, and the gas flow scouring curve was proposed. The following results were obtained: first, the reasonable salamander depth/hearth diameter ratio and bosh angle should be 23∼25% and 73°∼75° in China, respectively. Second, the key factors that influence the floatation of deadman and wear of the cooling stave are the deadman voidage and the slag crust thickness, respectively. Lastly, it is necessary to adjust some measures such as coke ratio, blow velocity and tuyere length. This paper is meant for optimizing the design of blast furnace. [ABSTRACT FROM AUTHOR]

The recent progress and development of ironmaking in China as of 2019 was introduced. China has achieved a remarkable progress in eliminating outdated production capacity of steel industry, accomplishing the upper limit target ahead of schedule to reduce production capacity by 150 million tons during the thirteenth Five-Year plan. The blast furnaces are gradually forming a four-element burden structure of "sinter+pellet+lump+scrap", adapting to the increase of scrap supply in society. Large-scale blast furnaces has been the development trend, 25 blast furnaces with inner volume exceeding 4000 m3 are in operation by now. In order to cope with the environmental protection policy and benefit from the sufficient supply of steel, the direct reduction process has gained a booming development opportunity in China. Although the smelting reduction has formed a certain scale in China, it still cannot compete with blast furnace ironmaking process in terms of energy utilization efficiency. [ABSTRACT FROM AUTHOR]

The ironmaking industry in China is developing rapidly. This paper discusses the status, technological progress, issues, and possible development directions of ironmaking in China. Because the standards for waste discharge and energy consumption have become more redundant, the steel production capacity has decreased by ∼145 million tons from 2016 to 2018. New sintering and coking technologies, such as water vapour spray sintering, high-temperature exhaust gas sintering, and semi-coke utilization, have led to distinct energy and efficiency improvements. Moreover, blast furnaces (BFs) are becoming larger and more intensive, due to which labour productivity has increased noticeably. However, some issues still remain, such as high fuel ratios, hot blast temperatures, and BF longevity. Nevertheless, eco-friendly and intelligent ironmaking is gaining importance and could be the development directions of the future. [ABSTRACT FROM AUTHOR]

The article discusses the blast-furnace smelting process in China, Japan, North America, Western Europe and Russia. It is stated that as pig iron production has risen, here has been a change in the composition of the blast-furnace charge in China. The article mentions that thin-walled hearth lining composed of small hot-pressed carbon blocks is part of the overwhelming majority of blast furnaces in North America.