4. Environment

The slag leaving the blast furnace contains sulfur, which, on contact with air, transforms into dioxide and sometimes gives off hydrogen sulfide with the water; this release is often mixed with the steam caused by cooling the slag in the pit, and especially by granulation. It is practically impossible to capture these vapors above the pits, gutters or granulation basins; however, the granulation pot can be topped by a chimney that collects the steam, where it is condensed by spraying with water. Water contaminated by granulation can be recovered, cooled and reused.

Pelletizing produces specific nuisances: noise, due to the drum's operation, and the occasional formation of slag wool, which scatters around the plant. The remedy for these nuisances is to install a hood fitted with a mesh that retains the slag wool like a filter. In return, the sulfur is trapped in...