No abstract

The quality of raw materials (iron ore, coal, and coke) has a clear impact on the carbon emissions of the hot metal production in steel making. So far, very little work has been done to measure and quantify this impact. Yet for benchmarking, technology choice and general carbon optimization are important elements. The total slag production of a blast furnace gives an accurate and relevant measure of the raw materials quality and is the main variable on which plant operators have no control. To quantify the impact of a varying amount of slag produced together with hot metal, a method is developed based on a differential approach. For a number of different blast furnaces with different operating points and burden compositions, the carbon footprint or carbon cost of slag production is determined using this method and a robust value for the carbon cost of the slag is derived. This value can also be used in the comparison of the carbon cost of different steel making routes or in life cycle assessments for steel and slag applications.