All about Cement
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Industrial ecology

Cement manufacturing does have an impact on the surrounding environment so Lafarge is committed to reconciling industrial imperatives with the preservation of ecosystems.

Becoming more sustainable is a commitment in all of our operations

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. Nature does not produce waste. In natural ecosystems whatever is waste for an organization becomes raw material for another.

 

Industrial ecology is an established practice and proposes a new organization of the industrial system, minimizing materials lost in the consumption and production processes. This approach requires interdependency and synergy between various industries, in order to recover residues from one industry in the production processes of another, thus becoming a resource.

Almiros quarry

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.

 

Industrial ecology practices are, therefore, beneficial for the community and the environment and also have benefits for Lafarge.

Alternative 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), industries, and urban areas.

 

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 and preserve non renewable fossil fuels.

 

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.

 

In Greece, Heracles uses in its Volos plant biomass comprised of agricultural residues from the area, since 2008. 

 

In 2013, we initiated co-processing of SSW (solid shredded waste) in Milaki plant as we concluded with the licensing procedures after delays of several years. SSW comes from local recycling plants (blue bins and industrial/commercial) and specifically from the recycling residue (mostly paper and wood) that otherwise would be land-filled. So far, the substitution accomplished is ​​at very low levels (4.8%), much lower than the current European practice, but we aim to increase it.    

Biomass used as an alternative fuel at Volos plant

Biomass used as an alternative fuel at Volos plant

Alternative raw materials

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

 

Reducing the amount of clinker in cement offers two advantages. Reduction in the consumption of natural, non-renewable raw materials, and the emissions of greenhouse gases. A cement produced with 30% additives uses 230 kg or 27% less CO2 than a conventional cement produced without additives.

 

Cement additives may be of natural origin like limestone and pozzolane and industrial origin like waste products from other industries, such as pulverized fuel ash from coal fired plants or slag from steel-industry blast furnaces.

 

These waste products have hydraulic binding properties and may substitute clinker under certain conditions. For example, in Greece, Heracles blends pulverised fuel ash and pozzolane into some of its bulk and bagged products.

Clinker

Clinker is the main ingredient in cement. These hardened granules are obtained by firing a mixture of approximately 80% limestone and 20% clay to a high temperature. Cement is obtained by grinding clinker, in some cases supplementing it with additives.

CO2 and cement

Why does the manufacture of cement produce CO2?

Cement manufacturing is the source of 5% of global CO2 emissions. The cement industry is a natural producer of CO2:

60% of emissions are due to the transformation of raw materials at high temperatures (the "decarbonization" of limestone),

40% result from the combustion required to heat the cement kilns to 1500°C.

Pulverised Fuel Ash

Pulversied Fuel Ash (PFA) is hydrophilic and can be used as a cementitious additive. The ash, which is collected from chimney filters in coal-fired power plants, is composed of vitreous silica, alumina, iron oxide and lime.

They can be used as a partial substitute for clinker and thus help to reduce CO2 emissions

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. 

 

Heracles in Greece considers the use of alternatives and the pursuit of industrial ecology to be separate but complementary parts of its core business. The company has developed a highly professional resource recovery business to source potential materials that can meet the stringent quality parameters required for use in cement-making.

 

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Enhanced Cements

Heracles GCCo, pioneer in the differentiation of cement products in the Greek market, offers to the market the new enhanced reactivity cement series HeraclesTM Ενισχυμένο and BasisTM Ενισχυμένο. Driven by innovation for the development of materials and solutions for the construction sector, Heracles has implemented, for the first time in Greece, the innovative technology of separate grinding in the cement production. 

Industrial ecology

How to create value from waste

Large amounts of natural resources, particularly minerals and fossil fuels, are used to manufacture cement. For many years the Group has been working to reduce the environmental impact of its activities by finding ways to obtain value from waste products.

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LafargeHolcim. Cement, aggregates, Concrete.