Temperature estimates of historical Pb-Ag smelting slags: A multi-methodological approach. (December 2022)

• Record Type: Journal Article
• Authors: Julia Westner, Katrin; Klein, Sabine; Sergeev, Dmitry; Müller, Michael
• Is Part Of: Journal of archaeological science. Volume 46(2022)
• Publication Date: 2022-12
• Subjects: Slag -- Lead -- Phase diagram -- Geothermometry -- DTA-TG -- Hot stage microscopy; Archaeology -- Periodicals; Archaeology -- Research -- Periodicals; 930.1
• DOI: 10.1016/j.jasrep.2022.103654
• Languages: English
• ISSNs: 2352-409X

Abstract

Highlights: Experimental and theoretical temperature estimates for representative Pb-Ag slags. Detailed mineralogical study of samples essential for all methods. DTA-TG and HSM experiments can greatly contribute to the characterisation of slags and technological reconstructions. Wide range of liquidus temperatures with consequences for archaeometallurgical practice. Abstract: The process temperature is a key parameter for the reconstruction of historic smelting operations since it can provide valuable information on the technological state-of-the-art as well as on intrinsically related aspects such as the type and availability of fuel (e.g. charcoal, wood) and metallurgical know-how. Slag compositions in lead-silver metallurgy can show a wide variation due to the utilisation of variable raw materials and possible addition of fluxes, but also since Pb oxide can be a major component, affecting the thermal behaviour and viscosity of the slag melt. This study presents results for liquidus temperatures determined by a range of different data-based and experimental techniques – phase diagrams, thermometry calculations, differential thermal analysis-thermogravimetry (DTA-TG) and hot stage microscopy (HSM) – applied to a suite of slags broadly representative of the compositional and mineralogical spectrum of metallurgical remains of lead-silver smelting. We propose suitable applications of the different techniques and provide generalised archaeometallurgical implications for the investigated slag types.