THE PURPOSE OF SHAFT-TYPE FURNACES OF THE WEST ASIAN METALLURGICAL PROVINCE

Abstract

The article addresses the problem of the functional purpose of shaft-type furnaces with chimneys found at the Late Bronze Age sites of Northern Eurasia. This category of thermal engineering structures became widespread in the eastern wing of the West Asian (Eurasian) metallurgical province. Thermal sets with flue channels are physical evidence of the implementation of technological algorithms of the pastoral model of metal production based primarily on multistage processing of secondary copper sulfides. Shaft furnaces with flues of the Ural-Kazakhstan region are functionally similar to the more structurally simple fi re pits-furnaces present in the structure of mining and processing complexes of the steppe Cis-Ural region. They were intended for decrepitation, pyrotechnic enrichment, and refining of ore protolith during a long fi re setting using brushwood and wood fuel at relatively low temperatures in the range of 600–800 °C. The degree of complexity of thermal engineering structures was determined by the nature of the raw materials used. Ordinary fi re pits turned out to be acceptable for ore-bearing complexes in the copper shales and sandstones of the steppe Cis-Ural region. The ores of the ultrabasic deposits of the Ural-Mugodzhar region were difficult to be processed and required the use of mine furnaces with flues, which were also characteristic of the metal production centers of the Kazakhstan mining and metallurgical region. Further improvement of thermal engineering structures with flue channels was due to the need to overcome the raw material crisis caused by the exhaustion of available sulfide reserves in secondary enrichment zones within ultrabasic deposits, and copper shale ore occurrences at the end of the Bronze Age. It required the transition to the use of chalcopyrite and greatly contributed to the discovery of iron metallurgy.