Slag Identification at Southern African Archaeological Sites

Abstract

nents of southern African Iron Age sites. Their correct identification is crucial to understanding technological processes performed at these sites. This paper presents criteria for distinguishing between iron smelting slags, iron forging slags, copper smelting slags, crucible slags resulting from melting activities, vitrified clay and various biomass materials. Slag identification should entail a combination of morphology, microscopic study, chemical analysis, and assessment of the archaeological context. It is a necessarily specialist activity and superficial classification without materials analysis can be misleading. Archaeologists need to be mindful of both the archaeological opportunities and the potential technical difficulties in the interpretation of slags.

Interrogantes De La Metalurgia Prehispánica Andina: Nuevas Propuestas Desde Los Hornos De Quillay (Catamarca, Argentina)

“…Las escorias son los desechos resultantes de actividades pirometalúrgicas, ya sean estas operaciones de reducción de minerales o de refinación de un metal impuro (Miller y Killick 2004). Sus características composicionales y microestructurales nos brindan información respecto de estos procedimientos, los materiales empleados, Figura 5.…”

The Archaeology and Technology of Metal Production in the Late Iron Age of the Southern Waterberg, Limpopo Province, South Africa

“…Since, production remains for these metals can only be positively separated in a full scale metallurgical analysis and not in hand specimen (Miller and Killick, 2004;Rehren and Pernicka, 2008), it was important to consider all metals that were worked in the area under study.…”

“…This chemistry can then be used to establish the metal which was being produced, and to establish relationships between the ores, slags, technical ceramics and metallic artefacts. These analyses characterise the reductive skills of the smelters (Bachmann, 1982;Joosten, 2004;Miller and Killick, 2004;Chirikure 2005). The main concern with this method is that sample homogenisation, assumes and imposes homogeneity on pre-industrial remains that were rarely homogenous to begin with (Pryce, 2008).…”

“…Both copper and iron smelting produce iron silicate slag because they all involved the same slag formulation to eliminate silica (SiO 2 ) and other rock components of the ores (Rostoker and Bronson, 1990;Miller and Killick, 2004). It is also possible to produce high levels of iron in copper smelting (Craddock and Meeks, 1987).…”

“…The focus is on the identification and characterisation of the metallurgical remains using science-based approaches as opposed to the "archaeology of a metal…free from any scientific input" (Rehren, 2000: 967). Archaeological methods alone cannot positively assign particular production remains to their respective metals or production stages without the use of science-based approaches (Sillar and Tite, 2000;Miller and Killick, 2004;Rehren and Pernicka, 2008). In the present study, the positive identification of metals worked and their associated techniques was important because, as discussed in Chapter 1, this thesis sought to identify all the metals worked pre-colonially and to expose their technology.…”