The fair distribution of natural resources to current and future generations is one of the fundamental goals of sustainable development. Increasing economic progress in many countries demands that we deal intelligently with the resources. In order to conserve natural resources, we are making increasing use of by-products or waste materials from other industries. The replacement materials are either used as raw materials or replace fossil energy sources in the burning process.
Alternative fuels
Where possible, we replace fossil fuels with alternative fuels. The materials employed depend, for example, on their availability and their calorific value. We also consider the chemical composition in order to avoid harmful emissions and negative effects on the product's environmental compatibility. When selecting and using alternative fuels, we follow the guideline developed jointly in the World Business Council for Sustainable Development.
Used tyres and waste oil have been used as alternative fuels in cement production for a long time. Our most commonly used alternative fuel is plastic, often mixed with production waste from paper, cardboard or textiles. Biomass is also becoming increasingly interesting. This includes, for example, meat and bone meal, which has been used across Europe since the BSE crisis. In addition, we use wood and, to an increasing degree, sewage sludge, nutshells and rice husks, as well as other locally available materials, for energy.
Alternative raw materials
Alternative raw materials are used both in the production of clinker, the most important intermediate product in cement production, and as an additive in cement grinding, in order to conserve natural raw material resources and reduce the proportion of clinker in the end product cement. We use blast furnace slag from steelmaking or fly ash, a by-product in coal-fired power plants. In recent years, we have further increased the proportion of alternative raw materials. In 2007, the figure was already 12%. We were able to reduce the proportion of clinker in the end product cement to 39%.