Page 176 - Materials Chemistry, Second Edition

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Recycling Solid Wastes 147
Ore fumes

Coke Sinter Limestone
plant machine
Coke fines Fuel

Sinter
Coke
Blast Iron ore, pellets
furnace
Slag

Hot Iron

Open- Basic Electric Ore, scrap
hearth oxygen arc
steel steel steel
furnace furnace furnace
Molten steel Molten steel

Ingot
pouring

Semifinished
shape rolling
mill

Hot-rolling
mill

Acid
pickling

Cold-rolling
mill

FIGURE 6.5 Schematic of the steelmaking process.

shredding, such appliances must be checked for the removal of potentially useful or hazardous
materials. For example, equipment manufactured prior to 1979 may contain polychlorinated
biphenyls (PCBs) within electrical capacitors; similarly, CFCs may be present in compressor units
in refrigerators or freezers.
Old automobiles are a major source of ferrous scrap. About 75% of an average automobile
can be recycled (Rhyner et al., 1995). Historically, most of the recyclable materials were ferrous;
however, plastics are becoming more common in automobile manufacture. Prior to processing for