Abstract: Based on the similarity between high-alumina ladle slag(LF) and calcium aluminate cement,this study proposes its utilization as a rapid-setting admixture for the design and preparation of temporary support materials in mining engineering. A systematic investigation was conducted to examine its influence on the hydration process and macroscopic properties of ordinary Portland cement. The results demonstrate that the incorporation of high-alumina ladle slag(LF) significantly modulates the setting and hardening behavior of the system. As its dosage increases,the setting time of the cement paste is markedly shortened,while the compressive strength of the cement mortar generally shows a declining trend across all tested ages. At lower incorporation levels(≤10%),the hydration process remains dominated by the Portland cement components. The calcium aluminate phases present in the slag are activated by calcium hydroxide and gypsum,accelerating the reaction kinetics and advancing the hydration acceleration period,thereby reducing the setting time to meet the rapid-response requirements for temporary support. At higher dosages(≥15%),the early hydration becomes governed by the calcium aluminate minerals. Gypsum is rapidly consumed,leading to the fast formation of substantial hydration products such as ettringite,which induces flash setting and rapid hardening. Under these conditions,Portland clinker particles become encapsulated,significantly prolonging their hydration induction period and consequently restricting later strength development. This study elucidates the mechanistic role and performance evolution of high-alumina ladle slag(LF) as a functional admixture at varying dosages,providing a theoretical foundation for the development of mining-specific temporary support materials based on industrial solid wastes.