In November 1969, New Zealand Steel Ltd pioneered the commercial use of the SL/RN solid fuel direct reduction process to make sponge iron as a feed material for electric arc furnaces._x000D_
Serious process problems with the use of green balls and coal injection were progressively overcome. The process was developed by New Zealand Steel along a radical route, of feeding the fine grained raw ironsand concentrate and coal directly to the kiln._x000D_
Contemporaneously with this development of direct reduction, steelmaking process innovations were made that enabled the arc furnaces to operate successfully with the high volumes of acid slag._x000D_
The further expansion of New Zealand Steel's primary steelmaking capacity to replace the currently imported hot and cold flat rolled products is under consideration._x000D_
The requirement to produce about 600 000 tonnes of steel slabs will be an opportunity to further modify iron and steel making plant and processes to optimise the economics. The conceptual and preliminary engineering selection of options is described.