What Is Clinker
Clinker is made of four main raw materials; limestone (78%), sandstone (11%), shale (10%), and iron ore (1%). These materials make up almost 99% percent of clinker.
How Clinker Is Made
Seven steps go into the manufacture of clinker – crushing, mixing, grinding, blending, feeding, burning and cooling. The clinker “burning” process is the most vital step. The raw materials of limestone, shale, sandstone and iron ore are coal-fired at a constant temperature of 1,450 degrees Celsius within a 4m wide, 60m long rotary kiln. Ultimately, the production of quality clinker depends on consistent purity of its raw materials and consistency in the coal-firing process.