Hachinohe Smelting Company Limited operates the largest Imperial Smelting Furnace (ISF) in the world, producing 112,000 t/y of zinc and 45,000 t/y of lead. The slag fuming plant has been operating in the smelter since 1993 for the recovery of zinc and lead from the ISF slag. In November 2001 the second slag fumer was commissioned in series with the existing fumer to improve the quality of slag for use in cement manufacture and to increase zinc and lead recovery in the fume. Along with the increase of zinc production, the on-site power generating capacity was uprated from 7.5MW to 9.6MW in April 2001. As much as 70% of the total power requirement is supplied by the own power plant. In recent years, up to 40% of the feed materials have comprised secondary zinc materials.
