1 - Raw Materials

Raw materials are mineral substances containing calcium, silica, alumina, and iron oxide. Since these components are rarely found in the correct proportions within a single source, it is necessary to create a specific blend. This mixture typically consists of 80% high-calcium material (limestone) and 20% low-calcium material with a higher concentration of silica, alumina, and iron oxide (clay or marl).

Limestone and marl – or clay – are extracted from quarries, crushed, and transported to the cement plant, where they are stored for use in production.

Limestone: Calcium Carbonate (CaCO_3)

Limestone is widespread in nature and has a finely granular crystalline structure. Its hardness depends on its geological age: the older the formation, the harder the stone. Its color is influenced by clay mixtures and iron compounds within it, which in turn affects the color of the final product. The purest forms of limestone include calcite, aragonite, and marble.

Marl and Clay

Marl is a specific type of limestone containing inclusions of silica, clay, and iron oxide. From a geological perspective, marls are sedimentary rocks formed by the simultaneous deposition of calcium carbonate and clay. Marl is softer than limestone; the higher the clay content, the lower its structural resistance. Its color varies from yellow to greyish-black, depending on the specific clay substances present.