Industrial Ecology

Cement manufacturing consumes large quantities of non-renewable raw materials (minerals and fossil fuels). It is also an important source of CO₂ emissions. 

In response to this environmental challenge, Lafarge has been committed to the path of industrial ecology since the mid-70s. This approach is inspired by the cycles of creation, destruction and recycling that occur in nature.

By rethinking industrial processes from start to finish, one industry's waste products can become another industry's resources.

Why find uses for waste? 

The Group is aware of the impact of its activities on the environment. As a result, Lafarge started thinking at a very early stage about ways of reconciling industrial imperatives with the preservation of ecosystems.

Adding value to waste by using it as alternative fuel or materials, makes it possible to:

• limit greenhouse gas emissions by reducing the use of: non-renewable natural raw materials, fossil fuels (oil, coal, etc.),
• diversify energy resources and reduce energy costs by limiting dependence on the market for traditional fuels,
• serve the community by recycling waste that would otherwise have to be processed and eliminated.

Waste-derived fuels

Waste products can be a very appealing alternative to fossil fuels. In general, alternative fuels are derived from waste or byproducts from agriculture (biomass) and industry:

• Chipped used tyres
• Processed Sewage Pellets (PSP)
• Meat and Bone Meal (MBM)
• Solid Recovered Fuel (SRF)

All of these products can be recycled as waste-derived fuels and burned safely in cement kilns.  This approach relieves the community of the need to process this waste and helps to limit CO₂ emissions. The extremely high temperatures found in cement kilns mean that the waste is totally eliminated and does not leave any residue.  At present, alternative fuels account for 10.7% of the Group's fuel use across all businesses.

Waste-derived materials 

The cement manufacturing process generates CO₂ because the limestone needs to be heated to very high temperatures. This physical-chemical process of "decarbonation" produces clinker, which is then ground down.  It is possible to reduce the amount of clinker in cement by using alternatives, called cement additions.  Reducing the amount of clinker in cement offers two advantages:

• a reduction in the consumption of natural, non-renewable raw materials,
• a reduction in the emission of greenhouse gases.

A cement produced with 30% additions uses 230 kg or 27% less CO₂ than a conventional cement produced without additions. Cement additions may be of:

natural origin:

• limestone

industrial origin:

• waste products from other industries, such as slag from steel-industry blast furnaces or pulverised fuel ash from coal-fired power plants.

These waste products have the same hydraulic binding properties as clinker. For example, in the UK, Lafarge blends pulverised fuel ash into a lot of its packed products.

Lafarge expertise results in safe waste solutions 

The use of waste products cannot be improvised. Lafarge has implemented stringent quality control standards as well as a training policy for its engineers, technicians and foremen. In this way, it is reinforcing the use of alternative fuels and materials while controlling industrial processes. The Group's R&D teams are also making an active contribution in this respect.