Study on the copper and iron alloy from the Bronze Age unearthed from the Yangtze River area in Anhui Province, China

Abstract

In the 1980s and 1990s, dozens of diamond-shaped ingots were unearthed from the Western Zhou Dynasty to the Warring States Period (1046–256 BC) from the ancient copper mining and metallurgy sites along the Yangtze in Guichi, Tongling, Nanling, and Fanchang in Anhui Province. These rust-colored metal ingots showed significant differences from the copper ingots unearthed in the area and were even designated as iron ingots or copper matte ingots when unearthed. Based on the previous work, the article analyzes these kinds of ingots unearthed in Nanling and Guichi by XRF, XRD, SEM and EDS, and OM (optical microscope). The result shows that the segregation of the copper-iron alloy samples analyzed is obvious, and the copper or iron phase in the supersaturated solid solution with dispersed state distribution can be seen in the samples. Therefore, these are not copper ice copper ingots, but iron supersatured copper-iron mixtures (alloys), which may be the earliest known artificial smelting of copper-iron alloys. It is produced by environmental control when smelting copper oxide ore containing iron by solid reduction.