Local cementation brass production during 12th–13th century CE, North China: Evidences from a royal summer palace of Jin Dynasty

Brass products in the coronet excavated from an M2-numbered Sui-Tang-dynasty tomb situated in Kun Lun Company in Xi'an, Shaanxi

“…Finally, in the third stage dated back to around the fifteenth century and with the availability of zinc metal, brass could be obtained by smelting pure copper and metallic zinc [17]. Thus, the composition distribution and metallographic structure of the sample were consistent with brass prepared by smelting copper ore [35,36] consisting in melting an appropriate mixture of zinc ore and copper ore over 920 °C [12,22]. Furthermore, it could be inferred that brass in the coronet was obtained by purposeful smelting of zinc ore.…”

“…In the second stage, cementation technology, taking its origin from the west at around 1400 BC, became the standard method of brass production in China in the tenth century. According to this technology, copper sheets were mixed with zinc oxide or carbonate and charcoal in an unsealed crucible [22]. When heated, zinc ore was reduced to metallic zinc vapor and diffused into copper, forming brass then.…”

“…Since there were a few brass products dating back before the fifteenth century AD, a lot of knowledge about brass came from the ancient documents. Moreover, before the tenth century AD, brass was a precious metal in China, being the second after gold and silver only, and was used exclusively by elites [22]. Judging from the shape and structure of the tomb and the unearthed artifacts, the male tomb owner should be an official of rank five or higher.…”

“…However, some scholars considered those utensils as imported brass that was introduced into China from the West along the Silk Road [2,21]. Then, twenty one local brass products originating from the mid-late Jin Dynasty epoch (金1189-1217 AD) were unearthed in Hebei (河 北) Province, which proved that diffusion and localization of brass cementation technology occurred in Northern China during the twelfth-thirteenth centuries AD [22]. Recently, low concentrations of zinc (2-4 wt%) were found in some Southern Song coinages (南宋1127-1279 AD), which reflected the sporadic input of recycled brass Buddha statues into the raw material melts [23].…”