K. Noro et al., NECESSITY OF SCRAP RECLAMATION TECHNOLOGIES AND PRESENT CONDITIONS OFTECHNICAL DEVELOPMENT, ISIJ international, 37(3), 1997, pp. 198-206
''New Steelmaking Process Forum'' was inaugurated in 1991 for the purp
ose of developing an innovative process capable of contributing to glo
bal environmental protection, such as the effective utilization of iro
n resource and the reduction of carbon dioxide generation, by recyclin
g the total volume of scrap. This paper outlines the Forum's activitie
s. The contents of tramp elements, copper and tin, of waste scrap were
predicted to increase to 1.5 times and 1.2 times the present values i
n 2010. Even if the largest possible amount of waste scrap is recycled
within the allowable ranges of steel product composition values, 150-
300 million tons of waste scrap will be heaped up in Japan. Therefore,
copper and tin removal technologies were developed. For the mass impu
rity (copper), the technology to crush scrap at low temperature at the
time of pretreatment and the technology to automatically discriminate
and separate impurity-attached scrap were developed. For the surface
layer impurity (tin), the technology to remove it by oxidation in a hi
gh-temperature oxidizing atmosphere at the time of preheating and melt
ing and the technology to remove it by evaporation in a weakly oxidizi
ng atmosphere were developed. For zinc, the technology to remove it fr
om dust in an externally heated kiln was developed.