Scoria brick
Iron slag brick
From Wikipedia, the free encyclopedia
Scoria brick[a] is a type of blue-grey brick made from slag, originally manufactured from the waste of the steelworks of Teesside, common across the North-East of England.[3][4] The bricks were also exported around the world and can be found in Canada, West Indies, Netherlands, Belgium, United States, India and South America.[5]
The word Scoria originally comes from Greek, meaning "Excrement", but came to be used by the Romans for a kind of volcanic rock.[5] The bricks were invented by Darlington industrialist Joseph Woodward, in the 1870s, with him registering a patent in 1873 and forming the "Tees Scoriae Company" the same year.[6][1] At its peak the company was taking 30% of the slag from the South-Tees works.[3]
The bricks were produced by pouring the slag cauldrons, coming on trains from the steel works, into moulds made with hinged bottoms and mounted on a revolving platform allowing the moulds to be filled separately. As the bricks solidified they were removed and placed in a beehive oven, where the residual heat annealed the whole of the brick.[7][2] The bricks were found to be extremely durable against water, frost, chemicals and heavy loads, which led to them being used as a road surface.[4] On the other hand, an early trial of the bricks in Liverpool found the bricks to wear unevenly and become slippery in wet conditions.[8]