The researchers found that using manganese rich slag instead of expensive manganese ore can produce high carbon ferromanganese efficiently. By replacing 50% of the sinter with slag containing 32% manganese, operating under specific conditions, they achieved the highest manganese content, recovery, and metallic yield. Charging 20-25% manganese slag in the blend can reduce production costs by 13% for manganese ores and 6% overall, making the process economically efficient.