In the 1100’s Europeans had mastered a technique for
producing cast iron, some 1,500 after the Chinese. This was by means of a blast
furnace, so called because of the blasts of air required to achieve a high
enough temperature to melt iron. Water and sometimes wind power were used to
operate the bellows and for crushing up the iron ore to increase its surface
area. Blast furnaces gradually grew in capacity to meet the demand for the new
cast iron, which had wider applications than wrought iron, but two distinct
problems arose as a result.
Charcoal began to run short as Europe ’s
trees were increasingly felled, and slag impurities prevented as much as 50
percent of the iron from being run off for casting. The introduction of coke
and lime into the process, solved both of these problems, but not for several
centuries to come.
No comments:
Post a Comment