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Bureau of Mines / Minerals yearbook: Metals and minerals 1978-79
Year 1978-79, Volume 1 (1978-1979)

Zlobik, Alvin B.
Slag: iron and steel,   pp. 821-833 ff. PDF (824.2 KB)


Page 821

  821Slag-Iron and Steel 
Alvin B. Zlobik1 
 Combined sales and usage of iron and steel slag in 1978 and 1979 totaled
36.9 million tons2 and 35.8 million tons, respectively. Iron slags totaled
28.4 million tons in 1978 and 27.5 million tons in 1979; steel slag totaled
8.5 million tons and 8.3 million tons in these respective years. Total sales
value 
for 1978, $101 million, was 23% higher than in 1977 and increased further
to $111 million in 1979. Average value per ton of iron slag was $3.04 in
1978 and increased 10% to $3.35 in 1979. Average value per ton of steel slag
increased 30% to $2.24 in 1979. 
DOMESTIC PRODUCTION 
Iron slags sold or used in 1978 increased 
10% in tonnage to 28.4 million tons and 
21% in value to $86.4 million. Sales/use of 
expanded iron slag increased significantly, 
30% in quantity and 50% in value over that 
in 1977. Sales of iron slag in 1979 decreased 
3% in quantity but increased 7% in value 
from that in 1978. The average value per 
ton of all iron slags in 1978 was $3.04 while 
the average value in 1979 was $3.35. Steel slags sold or used in 1978 and
1979 
totaled 8.5 million tons and 8.3 million tons and had values of $14.5 million
and $18.5 
million, respectively. 
 Pennsylvania, Ohio, and Indiana, in that order, were the leading producing
States during the 1978-79 period. Steel slags were processed at 39 operations
in 15 States during 1979. 
 In 1978, approximately 75% of iron and steel slag products in the United
States were shipped to market by truck; 82% were shipped by truck in 1979.
Rail and waterway shipments averaged 12% and 4%, respectively, during the
1978-79 period. The remaining material was used onsite. 
CONSUMPTION AND USES 
 There were no known imports or exports of iron or steel slags in the 1978-79
period. As usual, most domestic slags were consumed in the construction industry.
 Most salable iron slag banks in the United States have been exhausted, and
the availability of iron slag is largely dependent on newly produced blast-furnace
iron from iron and steel plants. An undetermined tonnage of steel slag banks
exists. Before it can be utilized, some steel slag requires a natural aging
process in order to minimize expansion, due to the hydration of free lime,
during end use. Some iron and steel slags are high in metallic iron content
and un 
suitable for sale to the construction industry; however, these high iron
slags can be recycled to the blast furnaces. 
 Air-cooled iron blast-furnace slag continued to be the most important slag
product in terms of both tons processed and in the number of different types
of use. Locally, iron slag is competitive with sand and gravel and crushed
stone, principally for use as aggregate. Air-cooled iron slag shows excellent
bonding characteristics when mixed with portland cement to make concrete.
It also shows high stability when used in asphaltic concretes and high skid
resistance when used in bituminous road surfacing. 


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