Cast iron-smelting furnace materials in imperial China: Macro-observation and microscopic study

Abstract

Field investigation was carried out to study ancient cast iron smelting furnaces at 15 sites from Imperial China. Petrographic analyses were performed on furnace materials to study the development of metallurgical ceramics used on these furnaces. The results show that furnace materials developed from simple clay material to a composite structure made of stone and clay. During the period from the 4th C. BCE to the 3rd C. CE, rammed clay or stacked clay bricks were used to build the furnaces; from the 7th to the 13th C. CE, furnaces were predominantly made with a durable outer wall constructed from stone, while the refractory material that lined the inner surface of the stone wall was composed of clay, sand and gravel-sized rock fragments. In addition, this paper discusses some aspects of governmental organization, furnace and smelting technology, economics which might influence this development, and examines the relationship between ceramic technology and metallurgy in Imperial China.