In 2020, U. S. Steel – Fairfield Tubular Steelmaking Operations achieved a significant milestone by transitioning from a blast furnace-QBOP to an electric arc furnace steelmaking process. Central to this transformation was the complete rede-sign of steel ladles, which are pivotal for ensuring a safe, stable and cost-effective operation. This article delves into the innovative features of the newly designed steel ladles, the advanced refractory lining configurations and the cutting-edge operational practices that have collectively propelled performance to new heights, setting a benchmark in the industry.

To improve mixing phenomena during steel refining process in a ladle, it is crucial to study metal-slag interaction. Using an acrylic model, scaled 1:8, two different lances were employed: one with two nozzles (inverted T shape), and the other with a single nozzle (L shape). The effect of gas flowrate and lance position on the mixing time, dye dispersion, and the slag eye opening at the reactor surface were evaluated. Mixing time decreased and the slag eye opening area increased as the gas flow was increased from 5 L/minute to 20 L/minute. The two-nozzle lance in the radial position (2R/3) provided better results.

In this work, the wear of the ladle slidegate plate was modeled and optimized to ensure operational safety, process stability and cost reduction associated with premature plate replacement. Adhering to established standards, such as limiting the maximum center hole size and maintaining crack-free conditions, prevents jamming and ensures steel flow control, thereby protecting both personnel and equipment. Premature replacement increases refractory, maintenance and labor costs while decreasing ladle availability. To address these challenges, a predictive tool was developed using a machine learning ap-proach to estimate and track the wear of the center hole diameter and crack formation in the slidegate plate.

The probability of alumina inclusion is strongly affected by slag chemistry and deoxidation practices. Moreover, the viscosi-ty of the slag should also be carefully controlled to suppress this harmful inclusion in secondary refining. The effect of physicochemical properties of FetO-bearing calcium aluminate–based system RH slag on the removal rate of alumina in-clusions in Al-killed steel has been investigated by considering the interfacial reaction between steel melts and the slag layer. The alumina removal rate is proportional to the physicochemical factor of the slag. The addition of FetO to RH slag with CaO/Al2O3 ≤ 1.3 effectively breaks the aluminate network structure, while the structure is less affected by FetO in the slags with CaO/Al2O3 ≥ 1.6. Consequently, even though FetO in the RH slag enhances the atomic oxygen pickup (i.e., reoxidation) from slag to steel melt, it contributes to inclusion absorption and dissolution by lowering viscosity of the slag in conjunction with depolymerization of the aluminate frame structure. Therefore, relatively basic slag (i.e., CaO/Al2O3 = 1.2–1.4) with appropriate amounts of FetO (T.Fe = 7–9%) would be recommended as an operational window to improve the cleanliness of molten steel in the RH degasser.

Recycled aggregates partially replacing virgin primary raw materials in new refractory brick production is a direct approach for CO2 footprint reduction. However, historic replacement rates tend to be very timid still, given paradigm concerns of prop-erty deterioration and reduced performance. This article presents how adequate concepts of correct utilization of properly sorted and processed recycled material can successfully provide a MgO-C brick grade with 30% reduced carbon emissions with improved properties and similar or superior performance compared to its standard primary raw material baseline con-ception.