From bowl furnaces to small shaft furnaces: new evidence from ancient bloomery iron smelting site at Liuzhuoling in Guangxi, Southern China, ca. 400 to 700 AD

A cultural relics survey conducted in 1987 in Liuchen (Pingnan County, Guangxi Zhuang Autonomous Region, China) revealed the oldest and largest group of iron smelting sites discovered in Guangxi and Lingnan region, one of the most important parts of southern China. While many surveys and studies have been conducted here, there is a lack of scientific excavations and comprehensive analysis of the metallurgical remains. Of the sites, only Liuzhuoling site (LZL) has been scientifically excavated and reported. This study conducted radiocarbon dating of charcoal samples, metallographic observations and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS) of iron block and slag from LZL. The radiocarbon dating results showed that the site dates range between 419 and 769 AD. Analysis of the slag and iron block indicated that it was a bloomery iron smelting site. All identifiable furnaces are small shaft furnaces. In previous studies, many bowl furnaces were found in the Guigang area. Considering the age of the ruins and comparison of furnace types, it appears that the bloomery iron smelting technology in the Guigang area may have transformed from bowl furnaces to small shaft furnaces. Our scientific analysis tentatively reveals the nature of the site and provides important clues about the origin and development of iron smelting technology in the Lingnan region of China. It is also of great significance to discuss the exchange and development of iron smelting technology between China and Southeast Asia.