The Extractive Metallurgy of Copper From Cabezo Jure, Huelva, Spain: Chemical and Mineralogical Study of Slags Dated to the Third Millenium B.C.

Abstract

The archeological excavations at Cabezo Juré, near Alosno, Huelva Province, in southwestern Spain, have recently revealed the vestiges of an ancient community of workers specialized in the metallurgy of copper (Cu); they were active between 2873 and 2274 B.C. (calibrated radiocarbon age). Evidence of their metallurgical activity has been found in remains of various furnaces, as well as large quantities of slag and copper products, both worked and as raw material. The results of the archeological, geochemical, mineralogical and textural studies performed on slags found in the area show that the recovery of copper was a twostage process. Primary fusion was obtained in furnaces at relatively high temperatures (~1200°C) with the addition of mafic rocks as a flux. Further refinement of the metal in crucibles produced slags with a mineral composition simpler than that at the furnace stage. The abundance of copper oxides in both smelting and refining slags suggests a highly inefficient metallurgical procedure, with only partial liberation of the copper from the ores.

Primary and secondary phases in copper-cobalt smelting slags from the Copperbelt Province, Zambia

“…Quartz corresponds exclusively to unmelted relics of the furnace charge. The presence of unmelted gangue (or flux) grains has been reported in many investigations devoted to historical pyrometallurgical slags (Ettler et al, 2009b;Sáez et al, 2003). When quartz is present in the slag (Figs 2b, 3b), we speculate that: (1) the temperature in the furnace was not high enough to melt completely the furnace charge (Ettler et al, 2009b); (2) the duration of melting was insufficient (kinetics effect) (Ettler et al, 2009b); or (3) the furnace charge was not defined correctly and the SiO 2 flux was overestimated.…”

Microanalytical study of copper ores from the Chalcolithic settlement of São Pedro (Portugal): Copper production in the south‐western Iberian Peninsula

“…There are some questions, however, regarding the production of Chalcolithic arsenical Cu alloys due to the low occurrence of As rich minerals in the supergene oxidized ores exploited during the third millennium bce in the south‐western Iberian Peninsula (Gaspar ; Sáez et al . ; Valério et al . ; Nocete et al .…”

“…A very small number of specimens belonging to settlements in south‐western Iberian Peninsula have been studied, indicating them to be composed of a mixture of Cu carbonates and iron oxyhydroxides without As (Gaspar ; Sáez et al . ; Nocete et al . ).…”

“… South‐western Iberian Peninsula with the location of São Pedro (SP) and other settlements with studied ore samples mentioned in the text: Porto Torrão (PT), Porto Mourão (PM), Cabezo Juré (CJ) and Valencina de la Concepción (VC) (Gaspar ; Sáez et al ; Nocete et al ). …”

The Provenance, Use, and Circulation of Metals in the European Bronze Age: The State of Debate

“…This has revealed many Bronze Age copper production centers throughout Europe, including mines in southwestern Ireland, Wales, England, Spain, France, Switzerland, Austria, Italy, Slovakia, Bulgaria, Romania, Greece, and Cyprus (see Fig. 1 ;Betancourt 2006;Boroffka and Heck 2006;Fontanals et al 2017;Höppner et al 2005;O'Brien 2015;Popov et al 2011;Saez et al 2003;Stos-Gale 1989Timberlake 2009;Weisgerber and Pernicka 1995 and references therein). Already it seems clear, however, that several large copper-mining areas were able at different times to establish dominant positions in metal supply in different regions (cf.…”