Alternative raw materials

In 2006 about 5% of the raw materials used in the production of clinker consisted of alternative raw materials, totalling about 14.5Mt/year. Alternative raw materials can be used to replace the traditional raw materials extracted from quarries, such as clay, shale and limestone, which are used in the kiln. Examples of alternative raw materials include contaminated soil, waste from road cleaning and other iron-, aluminium-, and silica-containing wastes, such as coal fly ash and blast furnace slag. The chemical suitability of alternative raw materials is important to ensure that they provide the necessary constituents for the formation of clinker.

The use of alternative raw materials provides numerous benefits, including a reduced need for quarrying and an improved environmental footprint of such activities.