Water quenching and grinding of ladle furnace slag for use as supplementary cementitious material in cemented mine backfills

As a secondary support material, cemented paste backfill (CPB) is widely used in underground mining operations. CPB is a mixture of mine tailings, water, and a small amount of a binder agent. In the Abitibi region of Canada, the standard binder typically contains 20 % general-use Portland cement (GU) and 80 % ground granulated blast-furnace slag (GGBFS). This binder combination reliably ensures that CPB meets the required unconfined compressive strength (UCS) targets. However, the rising cost of binders, the environmental impact of GU, and the limited availability of GGBFS have created a need for alternative materials. Efforts are underway to replace GU and identify substitutes for GGBFS in CPB formulations. This study explores the potential of ground granulated ladle furnace slag (GGLFS) as a partial replacement for both GU and GGBFS in CPB. Raw ladle furnace slag (LFS) was first quenched under pressurized water and ground to produce GGLFS. The GGLFS was then incorporated into various CPB formulations and pure cement pastes for testing. The results demonstrate that GGLFS enhances the reactivity of GU/GGBFS blends in CPB, achieving satisfactory UCS after 7 and 28 days of curing. Additionally, GGLFS accelerates the initial reaction and modifies the hydration products in GU/GGBFS formulations. These findings highlight the promising potential of GGLFS as a supplementary cementitious material in CPB applications.