US EPA

1352172 

Journal Article 

Large scale smelting of speiss and arsenical copper at Early Bronze Age Arisman, Iran 

Rehren, T; Boscher, L; Pernicka, E 

2012 

39 

6 

1717-1727 

10.1016/j.jas.2012.01.009 

WOS:000305041800007 

We report analyses of different slag types found at the Early Bronze Age site of Arisman in North-West Iran. Here, an estimated 20 tons of slag provide evidence of sustained and large-scale production of metal, using both furnaces and crucibles. The results show that both speiss, an iron-arsenic alloy, and arsenical copper were produced, apparently side-by-side at the same site but using different ores and processes. We offer a tentative outline of the metallurgical processes involved in the production of these arsenic alloys and an explanation why speiss needed to be produced from arsenopyrite in a separate step, instead of using the mineral in its native form as a source for arsenic. We suggest that the speiss was then added either to secondary copper ore or to separately smelted copper metal, in order finally to produce arsenical copper in a regular and well-controlled process. 

Arsenic; Copper; Smelting; Alloy; Early Bronze Age; Iran; Arisman