Development of a low-carbon sintering process technology and its application to a pilot-scale sintering testing

Abstract

The ironmaking process mostly consisting of coke plant, sintering plant and blast furnace accounts for about 80 % of total CO₂ emission from steel plants. Out of the total emission by steelmaking companies, the blast furnace is responsible for more than half (55 %), followed by sintering plant (12 %) and coke plant (10 %). The current study aims to apply a developed laboratory-scale technology to sintering test equipment (STE); a low-carbon sintering process. The technology also encompasses the recycling of by-products added to the sinter mix as calcium ferrites. Several morphological changes in views of pore size and phase constitution were made in the sinter containing calcium ferrite compared with the standard sinter. 1 kg STE was employed to check the viability of such technology. The comparison between standard and low-carbon sinters was made in views of sinter strength (tumbler index) and reducibility. The expected reduction in CO₂ emissions follows the reduction of 33 % in the coke ratio. Two different methods were performed: the first one by adding calcium ferrite without considering the basicity level, and the second one by maintaining the basicity constant, while decreasing the limestone content. In both cases, the sinter strength and reducibility were maintained at the same level as the standard sinter or improved. These obtained results showed that it is possible to maintain or improve the quality of raw materials used in ironmaking processes while significantly reducing the requirement for coke.