Trace element analysis reveals varied functions of copper processing crucibles from the Shang City at Zhengzhou

The Early Shang (sixteenth to fourteenth century BC) capital at Zhengzhou revealed two large-scale bronze casting foundries and a large amount of metallurgical remains. They have only recently been subjected to detailed chemical and mineralogical characterizations. Three different forms of metallurgical crucibles and a metal droplet were analyzed with SEM-EDS and ICP-MS. A micro-drill was used to sample both slag layer and ceramic body of crucibles. The analytical results demonstrate that three types of crucibles were made with different materials and used for varied metallurgical operations. Type A crucibles were used for refining raw copper or smelting high-purity copper ore, and have strongly elevated Co, Mo, Zn, and Mn contents in their slag layer. Type B crucibles were associated with alloying copper with tin ore since the delta Eu value of its slag layer is considerably higher than its ceramic body. The plant-tempered type C crucibles were bronze pouring vessels and did not develop a pronouncing slag layer. This research demonstrated that trace element analysis of crucible slag is an effective tool for reconstructing varied functions of metallurgical crucibles.

Automated summary

Through trace element analysis of metallurgical remains found in the Early Shang capital at Zhengzhou, different types of crucibles were identified for various metallurgical operations. This research provides important insights into reconstructing ancient metallurgical techniques and production methods.