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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 sociotechnological contexts, which are discussed using conceptual frameworks of rational economy and technological traditions.

The Basquesmith project aims to illuminate the cycle of iron production and consumption by early medieval rural farming communities in the Álava province, Basque Country, northern Spain.

The Incas appropriated many local metallurgical technologies throughout the Andes, each of which had its unique peculiarities and was based on local ancestral knowledge. The widespread use of tin-bronze during the Inca expansion, the development of mining and smelting sites, as well as ethno-historical records evidence the Incas’ interest in copper smelting, a key activity in the Andes since ca. 1400 BC. However, little is known about the technical parameters achieved by ancient metallurgists and the changes that occurred during the Inca expansion. In this paper, we address these changes through a case study of Copiapó valley, focusing on the Viña del Cerro site, one of the most famous Inca smelting centres of the southern Andes. Although this place was architectonically restructured by the Incas, its operations began long before the imperial expansion and used wind-powered furnaces. We analysed 19 slag and 11 copper ore samples using OM, SEM–EDS, WD-XRF, and XRD analyses. Results identified heterogeneous and viscous slags, rich in SiO2 (43 wt%) and poor in FeO (13 wt%). Copper retention was high (up to 60 wt%). Microstructural analyses indicate that slags were formed under unstable oxidising conditions, reaching temperatures that ranged between 1000 to 1100 °C. The copper produced was very pure. High-grade copper ores containing up to 69 wt% CuO were reduced at the site, combining carbonates (malachite, azurite), halides (buttgenbachite, clinoatacamite), and some sulphates (brochantite). We propose that even under the relatively unfavourable conditions for slag formation, the smelting conditions generated at Viña del Cerro were competent enough to extract metal, but not necessarily enough to form liquid slag. These conditions were facilitated by the local metallurgists’ thorough knowledge of the wind flow and their ability to select the right ore. This new information contributes to understanding the efficiency of metallurgical technology and the knowledge, skills, and adaptability of the ancient metallurgists from Copiapó valley, a group that was integrated into the economic networks of the Inca Empire.