The Iron Works
Roasting furnace and blast furnace
Horse carts pulled their loads of iron ore in pieces to the ironworks. But how did they get the iron out of the ore? Well, they had to build large furnaces – roasting furnaces and blast furnaces – which were as high as chimneys.
First, the pieces of iron ore had to be roasted in the roasting furnace to remove impurities. Then the iron ore was transported to the blast furnace, where it was melted using charcoal and a little lime.
A lot of charcoal was needed to make iron. The inside of the furnace was so hot that the pieces of iron ore melted and trickled down to the bottom. Large bellows blew air into the furnace through holes, and made it even hotter. The molten slag from the ore ended up on top of the molten iron in the bottom of the furnace.
So, the molten slag sat on top of the molten iron. The furnace master, who was in charge, would open a hole at the bottom of the furnace, and let the molten slag flow out in one direction. Then he opened a hole on the other side and let the molten iron out, onto the sand which had been brought there. It was so hot that you could burn yourself to death. The iron was bright yellow, like fire, and sputtered and sparkled.
The iron flowed straight into square moulds that had been made in the sand, and was allowed to cool. Now blocks of iron, or pig iron as it was called, had been made. Pig iron was also called cast iron.