Comparative Study of Metallic Iron Production from High-Phosphorus Iron Ores: Carbon-Composite Pellet Direct Reduction–Melting vs. Granular Direct Reduction–Magnetic Separation–Melting

High-phosphorus iron ore is an abundant yet refractory resource whose industrial exploitation is severely constrained by its elevated phosphorus content. Guided by the ore’s reduction characteristics, two process routes were designed and compared: carbon-composite pellet direct reduction followed by melting separation (CCP-DR–MS) and direct reduction–magnetic separation–melting separation (DR–MS–MS). Systematic experiments under simulated industrial conditions evaluated the metallization degree, dephosphorization efficiency, and smelting performance while clarifying the key factors that govern the differences in phosphorus removal between the two processes. The results show that both routes raised the ore’s metallization degree to above 95% during direct reduction, but the DR–MS–MS route delivered markedly better dephosphorization, achieving a maximum phosphorus removal rate of 89.20%. Although the slags produced by the two processes showed comparable phosphorus capacities, the difference in overall dephosphorization efficiency stemmed from their distinct reduction mechanisms: in DR–MS–MS, metallic iron is generated mainly via CO-mediated reduction, which suppresses phosphorus reduction, whereas in CCP-DR–MS, phosphorus and iron are simultaneously reduced by carbon. Consequently, DR–MS–MS attains superior phosphorus removal.