Polish coke

Before blast furnace coke was used, smelting the ore was done for many centuries, especially in China. The oldest extant blast furnaces were built in China in the first century before Christ (so called Han Dynasty period). However, weapons and farm tools made of cast iron had been widespread in China about four hundred years before and the iron smelters working in the third century before Christ had an average workforce of more than two hundred men each. All those early furnaces used phosphorus-containing minerals as a flux and had walls made of clay. The effectiveness of the Chinese blast furnaces of this period was enhanced much by the famous engineer Du Shi (he lived in times of Jesus Christ). His invention was applying the power of waterwheels to piston-bellows in forging cast iron.

Furnace bellows operated by waterwheels (Wang Zhen, “Nong Shu”, 1313)

It was long thought that the cast iron and blast furnace were developed by the Chinese. Donald Wagner has proved that the first bloomeries were in use at the beginning of the Chinese Bronze Age of the late Longshan culture (c. 2000 BC) and they migrated to China from the west. Wagner suggests that cast iron production and that early blast furnace evolved from furnaces which were used for bronze melting. One thing we know for sure – the iron weapons were essential to military success and unification of China by the time the State of Qin (221 BC). In the eleventh century after Christ (the Song Dynasty period) Chinese iron industry has changed a fuel used in iron cast and steel cast - from charcoal to bituminous coal. This was next step of evolution leading straightly to using of blast furnace coke.

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