Project NeoSmelt represents a major collaborative effort between BlueScope, BHP, Rio Tinto, Woodside Energy, and Mitsui Iron Ore Development to develop Australia’s largest ironmaking Electric Smelting Furnace (ESF) pilot plant. The initiative aims to demonstrate the technical feasibility of a Direct Reduced Iron (DRI)–ESF process using predominantly Pilbara iron ores, offering a potential lower emissions alternative to traditional blast furnace routes. Supported by $19.8 million in Australian Renewable Energy Agency (ARENA) funding for the front-end engineering phase (FEED), the project is progressing through FEED, with a final investment decision anticipated in 2026 and pilot operations targeted for 2028 in Western Australia’s Kwinana Industrial Area. The NeoSmelt pilot plant is designed to produce 30 000–40 000 t of molten iron annually. Early operations will rely on natural gas for ore reduction, transitioning to lower carbon-intensity hydrogen as the process matures. Success would provide a significant pathway to decarbonising steelmaking while continuing to leverage Australia’s substantial Pilbara ore resources, which contribute 38 per cent of global iron ore supply. For BlueScope, NeoSmelt aligns with long-term planning for Port Kembla Steelworks, where the reline of No. 6 blast furnace will maintain sovereign flat steel production while alternative low emissions technologies are developed and piloted. A central technical challenge for ESF viability is slag design, which critically influences heat transfer, feed dissolution, reaction kinetics, refractory interaction, and overall furnace stability. Slag properties including electrical and thermal conductivity, density, viscosity, liquidus temperature, solidification behaviour, interfacial tension, and chemical activity interact in complex and often competing ways. For example, slag resistivity enhances electrical heating but increases viscosity; flux additions reduce viscosity but alter density and settling behaviour; higher operating temperatures improve smelting performance but elevate the risk of refractory wear. Understanding these trade-offs is essential for optimising both furnace performance and campaign life. Systematic technical work from laboratory to pilot scale is required to address both slag fundamentals for the Pilbara system and the realities of industrial slags containing minor elements, entrained solids, gases, and metal droplets.