KOBM Slag

Brief Description

Klöckner Oxygen Blowing Maximillanshuette Slag (KOBM Slag) is a co-product of the steel making process used in New Zealand.

Physical Description

KOBM slag is typically light to medium brown in colour. KOBM slag has a physical appearance of coarse sand, including fine size particles. Based on its chemistry, KOBM Slag is pozzolanic with self-cementing properties. KOBM slag can be used as a feedstock for cement manufacture due to its pre-calcined nature, chemistry and contributions to reducing carbon emissions.

Method of Manufacture

A KOBM Oxygen Steel Converter vessel is used. The vessel is charged with the molten iron from the melter and a small proportion of scrap before refining begins using a top lance and bottom blown tuyeres to produce. The remaining steel making operation follows conventional practices, apart from the chemistry of the slag, which again differs from international equivalents due to irons and source.

Diagram of Manufacture

Applications

KOBM slag is high in fines and cannot be used as an aggregate for road-making or surfacings. KOBM can be used, however, as a lime substitute in stabilising clay sub-bases and as an additive to cement manufacture.