Copper and bloomery iron smelting in Central China: Technological traditions in the Daye County (Hubei)

This project investigates the copper and iron producing industries of Daye County, a substantial mining and smelting area in the Hubei Province (China) with activities well documented from the early 1st millennium BC. In particular, this study aims to characterise the engineering parameters of the primary smelting of copper and bloomery iron at eight metal production sites located in the proximity of the prominent ancient mine of Tonglushan, in an area of ~1300 km2 . The thesis is focused on the materials science analyses of surface collected technicalmaterial such as slags, furnace remains, and ores of eight archaeological sites located in close proximity of each other in the Daye County. The methods include optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), and wavelength dispersive X-ray fluorescence (WD-XRF), to characterise their microstructure, mineralogy and chemical composition. The copper-smelting technologies reconstructed here – broadly framed in the Western Zhou period by ceramic typology – seemingly correspond to modest size workshops, thus different from the large scale production centres involving numerous workers, resources and infrastructures typically described in the literature. Moreover, and exceptionally for most of Eurasia, extensive evidence of large-scale production of bloomery iron at the core of the Chinese Empire is documented, with radiocarbon dates placing the activity in the 18th century AD, thus in the Qing Dynasty and over 2000 years after the production of copper. This finding challenges traditional generalisations whereby bloomery iron smelting is widely deemed to be a rarity in China, due to the early development of the blast furnaces; when identified, bloomeries are usually presented as isolated examples of limited scale, mostly in marginal areas to the Central Plains. The reconstruction of the various smelting processes in a relatively small region illustrates different technological adaptations to natural resources and socio- technological contexts, which are discussed using conceptual frameworks of technological choices and regionalism

Bullion production in imperial China and its significance for sulphide ore smelting world-wide

Gold and silver production was of major importance for almost all ancient societies but has been rarely studied archaeologically. Here we present a reconstruction of a previously undocumented technology used to recover gold, silver and lead at the site of Baojia in Jiangxi province, China dated between the 7th and 13th centuries AD. Smelting a mixture of sulphidic and gossan ores in a relatively low temperature furnace under mildly reducing conditions, the process involved the use of metallic iron to reduce lead sulphide to lead metal, which acted as the collector of the precious metals. An experimental reconstruction provides essential information, demonstrating both the significant influence of sulphur on the silicate slag system, and that iron reduction smelting of lead can be carried out at a relatively low temperature. These new findings are relevant for further studies of lead and precious metal smelting slags world-wide. The technological choices of ancient smelters at this site are then discussed in their specific geographical and social-economic settings

Bloomery iron smelting in the Daye County (Hubei): Technological traditions in Qing China

China is widely accepted as the birthplace and shrine of the blast furnace, with bloomery iron technology largely believed to be scant before the Han Dynasty, and virtually inexistent afterwards. Challenging this traditional picture, this paper presents the material characterisation and reverse engineering of the primary smelting of bloomery iron at five metal production sites, located in close proximity of each other in the Daye County in Hubei Province, China, and in operation during the middle Qing Dynasty. A combination of materials science analyses–optical microscopy, SEM-EDS and WD-XRF–of surface collected technical material such as slags, furnace remains, and ores has demonstrated the established existence of bloomery iron at the core of the Chinese Empire. The five case studies present robust evidence of an overall broadly shared technical procedure based on the smelting of high grade ores in batteries of embanked furnaces, generating abundant slag but a limited metal output. The reconstruction of the various smelting processes in a relatively small region illustrates different technological adaptations to natural resources and socio-technological contexts, which are discussed using conceptual frameworks of rational economy and technological traditions.This paper is based on the PhD dissertation undertaken by David Larreina-Garcia at the UCL Institute of Archaeology, under the primary supervision of Marcos Martinón-Torres, carried out with the financial support of a UCL Impact Scholarship funded by UCL, the Institute for Archaeo-Metallurgical Studies (IAMS) and the Rio Tinto Group. Radiocarbon dates were obtained through the NERC/AHRC radiocarbon service (grant n° NF/2014/2/12)

Data for: Bloomery iron smelting in the Daye County (Hubei): technological traditions in Qing China

Full results (normalised) of WD-XRF data for bloomery slag samples, and precision and accuracy values of the machines monitored using certified reference materials (CRMs

Data for: Bloomery iron smelting in the Daye County (Hubei): technological traditions in Qing China

Full results (normalised) of WD-XRF data for bloomery slag samples, and precision and accuracy values of the machines monitored using certified reference materials (CRMs)THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV