The nature and properties of slag and dust generated during the manufacture of pig iron indicate the two possibilities of their utilization: sintering or cold agglomerating with Portland cement. Both sinter and pellets can be recycled in the LD converter. It was introduced the concept of "preformed synthetic slag" to use the recycling of waste. If the material contains components forming the eutectic properties similar to sinter or pellet (obtained outside the converter) it stimulates the creation of slag in the LD converter.The aim of this research is to address the best way to deal with manganese before the molten metal reaches the final stage of temperature and composition for casting. Ideally, the composition of the slag and dust produced by the BOF-LD can be adjusted so that the molten metal that reaches the secondary metallurgy contains over 1.0% manganese.