Its production process

GGBS is manufactured from blastfurnace slag, a by-product from the blast-furnaces that produce iron.

Production of blastfurnace slag

The blast-furnaces used to make iron, operate at temperatures up to 2000°C and are fed with a carefully controlled mixture of iron ore, coke and limestone. The iron ore converts to iron which sinks to the bottom of the furnace. The remaining materials form a slag that floats on top of the iron. The molten iron and slag are drawn off at regular intervals through tapping holes in the base of the furnace. After being tapped from the furnace, the slag is rapidly quenched in water. This process is known as granulation because it produces glassy granules, similar in appearance to a coarse sand. These granules have excellent cementitious properties.

Processing of the slag

To produce GGBS, this granulated blast furnace slag is dried and ground to a fine white powder.