Paul Craddock (1995) mentions the possibility that Roman metallurgists
recovered some zinc and perhaps lead oxides from the stacks of tall
lead-silver smelting furnaces. We are studying the mostly rubbly remains
of lead-silver smelters in Extremadura, Spain. We find many pieces of
roof tile that must have been deliberately placed like little protruding
shelves within an environment of lead-bearing hot gases, for their lower
sides and ends facing away from the wall are coated with 1-3 mm of a
hard glaze of lead oxide. The thickened rim of the roof tile was
generally/always mounted upward and the lower corner on many has little
“icicles” that assure of their original orientation.
Has anyone else observed features like these? In what context? Did the
Romans add any special constructions to the furnaces to help reduce
metal losses from the stack gases as was done in recent centuries?
Robert G. Schmidt
Research Associate, Anthropology Dept, Smithsonian, Washington, D.C.
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